20 Dec 2023

Bioinspired Squid Peptides─ A Tale of Curiosity-Driven Research Leading to Unforeseen Biomedical Applications

Publications

Every technological and biomedical breakthrough started with fundamental, blue-sky research. Such research often leads to unexpected path with unforeseen applications and that’s what makes it intellectually so rewarding. Such a journey on the fundamental discovery of squid proteins and peptides discovered in the squid beak and sucker ring teeth is described in our paper “Bioinspired Squid Peptides─ A Tale of Curiosity-Driven Research Leading to Unforeseen Biomedical Applications” published in “Accounts of Chemical Research”.

19 Dec 2023

Fluid protein condensates for bioinspired applications

Publications

Our review article “Fluid protein condensates for bioinspired applications” written in collaboration with Matt Harrington (McGill University) and Raffaele Mezzenga (ETH Zürich) is published in “Nature Reviews Bioengineering”. We describe how protein coacervates (condensates) have emerged as key building blocks during the biofabrication of biological materials and present latest bioinspired applications of these protein- and peptide-based condensates.

15 October 2023

Biomineralization of mantis shrimp dactyl club following molting: Apatite formation and brominated organic components

Publications

The paper by former BBML PhD student Isaiah Chua “Biomineralization of mantis shrimp dactyl club following molting: Apatite formation and brominated organic components”, in collaboration with the team of Henrik Birkedal at Aarhus University in Denmark, is published in Acta Biomaterialia. Mantis shrimp hunt using club-like appendages that contain apatite, chitin, amorphous calcium carbonate, and amorphous calcium phosphate ordered in a highly hierarchical structure. To understand the formation process of the club we have analyed clubs harvested at specific times since molting, so that we could “reconstruct” a club formation map. By combining several methods ranging from position resolved synchrotron X-ray diffraction to proteomics, we reveal that clubs form from an organic membrane with brominated protein and that crystalline apatite phases are present from the very onset of club formation and grow in relative importance over time. This reveals a complex biomineralization process leading to these fascinating biomineralized tools.

26 September 2023

Renewable Energy from Livestock Waste Valorization: Amyloid-Based Feather Keratin Fuel Cells

Publications

Our paper “Renewable Energy from Livestock Waste Valorization: Amyloid-Based Feather Keratin Fuel Cells” in collaboration with the lab of Raffele Mezzenga at ETH Zürich on using chicken feather to produce proton-conducting membranes is published in ACS Applied Materials & Interfaces. 40 million tons of chicken feathers are produced annually and then largely burnt, producing toxic sulfur dioxide. How about repurposing this massive waste into something useful, in particular clean energy applications? That’s exactly what BBML PhD student Wei Long Soon did: he extracted keratin proteins from chicken feathers, converted it into protein nanofibrils and then produced membranes that can conduct protons. These membranes can then be used in fuel cells. This research addresses multiple sustainable challenges: 1. It recycles a material that is not used for anything else into a useful product. 2. Along the way, it prevents emission of a toxic byproduct (sulfur dioxide). 3. Unlike other fuel cell membranes currently in use (such as Nafion), the membranes are much cleaner to produce and they are completely biodegradable after use. In contrast, Nafion is a fluorinated synthetic polymer that not only requires toxic chemicals during production, but it is also not biodegradable. 4. In a fuel cell, only water is produced. In that sense this technology has a negative carbon footprint. 5. Chicken feathers are abundantly available and cheap, enabling scaling up.

16 August 2023

Redox-Responsive Phase-Separating Peptide as a Universal Delivery Vehicle for CRISPR/Cas9 Genome Editing Machinery

Publications

Our publication “Redox-Responsive Phase-Separating Peptide as a Universal Delivery Vehicle for CRISPR/Cas9 Genome Editing Machinery” is published in ACS Nano. Following our 2022 publication in Nature Chemistry on a new type of peptide coacervates (HBpep-SP) that can cross the cell membrane and deliver large macromolecular therapeutics, first author Dr. Yue Sun has now demonstrated that HBpep-SP can readily deliver in cells the 3 forms of CRISPR-Cas9 editing machinery, namely pDNA Cas9 mRNA/sgRNA, and the ribonucleoprotein (RNP) complex. Compared to other non-viral delivery vectors for CRISPR/Cas9 9, our coacervates benefit from the following advantages: (1) a very simple composition and preparation, (2) facile and instantaneous cargo recruitment, (3) high uptake rate, (4) low cytotoxicity, and (5) most importantly, higher efficiency compared to commercially available reagents highly customized for CRISPR/Cas9 transfection.

13 July 2023

Monitoring Disassembly and Cargo Release of Phase-Separated Peptide Coacervates with Native Mass Spectrometry

Publications

Our publication “Monitoring Disassembly and Cargo Release of Phase-Separated Peptide Coacervates with Native Mass Spectrometry”, in collaboration with the group of Michael Landreh and Marie Arsenian-Hneriksson at Karolinksa Institutet in Sweden, is published in Analytical Chemistry. The paper described how mass spectrometry can be used to monitor peptide coacervates disassembly without labelling the peptides.

16 June 2023

Phase-Separating Peptides Recruiting Aggregation-Induced Emission Fluorogen for Rapid E. coli Detection

Publications

Our article “Phase-Separating Peptides Recruiting Aggregation-Induced Emission Fluorogen for Rapid E. coli Detection” is published in Analytical Chemistry. In this study, BBML’s PhD student Syed Maricar and Senior Research Fellow Sushanth Gudlur developed phase-separating peptides (PSPs) that can be used to rapidly detect the pathogen E. coli. The design consisted in incorporating a sequence motif within PSPs that is recognized and cleaved by proteases present in E. coli’s outer membrane and to recruit an aggregation-induced emission fluorogen during phase separation of PSPs. Depending on the presence or absence of E. coli, coacervates microdroplets with a strong fluorescence intensity are formed, enabling to detect E. coli with the naked yet under ultra-violet light.

20 April 2023

Biomineralization in Barnacle Base Plate in Association with Adhesive Cement Protein

Publications

Our article “Biomineralization in Barnacle Base Plate in Association with Adhesive Cement Protein” is published in the Journal of the American”, in collaboration with Prof. Souhir Boujday from Sorbonne University, is published in ACS Applied BioMaterials. In this article, using advanced surface spectroscopy techniques, first author Sunyoung Hur investigated how the barnacle cement protein MrCP20 regulates the biomineralization of the barnacle base plate. MrCP20 was shown to stabilize vaterite, the metastable polymorph of calcium carbonate and to self-assemble into b-rich rich fibrils that contributes to the strong adhesive behavior of barnacles to immersed substrates.

2 February 2023

Modulation of Mechanical Properties of Short Bioinspired Peptide Materials by Single Amino-Acid Mutations

Publications

Our article “Modulation of Mechanical Properties of Short Bioinspired Peptide Materials by Single Amino-Acid Mutations” is published in the Journal of the American Chemical Society (JACS). In this paper, first author Shu Hui Hiew has identified a family of short 8 amino acid peptide (“GX8”) in extra-cellular tissues of a wide range of organisms, suggesting that the occurrence of this short peptide sequence may be the result of convergent evolution. By single mutation of the last “X”, we also show that GX8 can be self-assembled into various supramolecular structures, exhibiting vastly different physicochemical and viscoelastic properties, from liquid-like coacervate microdroplets to hydrogels to stiff solid materials.

24 January 2023

Protein-Based Biological Materials: Molecular Design and Artificial Production

Publications

Our review “Protein-Based Biological Materials: Molecular Design and Artificial Production”, written in collaboration with Pezhman Mohammadi from the VTT Research Center in Finland and our MSE/NTU colleague, Prof. Jing Yu, is published in Chemical Reviews. Starting with a historical perspective on efforts over many decades to obtain the sequences of load-bearing protein materials, such as silk or mussel adhesive proteins, this comprehensive review then describes latest developments in sequencing and proteomic technologies that have allow to elucidate the sequence of intriguing protein-based biological materials. Artificial production of these proteins and their applications are also reviewed. The review is part of the “Sustainable Materials” special issue of Chemical Reviews.

9 January 2023

Peptide-based liquid droplets as emerging delivery vehicles

Publications

Our short review “Peptide-based liquid droplets as emerging delivery vehicles”, in collaboration with Dr. Jianhui Lui, Prof. Evan Spruijt from Radboud University, and Prof. Robert Langer from MIT, is published in “Nature Reviews Materials. The review explores recent drug delivery vehicles made of peptide-based microdroplets (coacervates).

1 October 2022

Plant-Based Amyloids from Food Waste for Removal of Heavy Metals from Contaminated Water

Publications

Our paper “Plant-Based Amyloids from Food Waste for Removal of Heavy Metals from Contaminated Water”, in collaboration with the lab of Prof. Raffaele Mezzenga at ETH Zürich, is published in “Chemical Engineering Journal”. In this paper, BBML PhD student Wei Long Soon has used protein-rich sunflower and peanut meals as low-cost raw materials, from which he extracted, isolated, and self-assembled proteins into functional amyloid fibrils. These fibrils were then used to fabricate membranes that can efficiently remove toxic heavy metal pollutants to drinkable standards with negligible energy consumption. This process could be easily scaled up due to its simplicity and minimal use of chemical reagents, and represents a low-cost yet efficient water treatment technology.

30 September 2022

Squid Suckerin‐spider Silk Fusion Protein Hydrogel for Delivery of Mesenchymal Stem Cell Secretome to Chronic Wounds

Publications

The article from BBML PhD student Kenrick Koh “Squid Suckerin‐spider Silk Fusion Protein Hydrogel for Delivery of Mesenchymal Stem Cell Secretome to Chronic Wounds” is published in “Advanced Healthcare Materials”. In this study conducted in collaboration with the teams of Prof. Dalton Tay (MSE) and Prof. Andrew Tan (LKC and SBS), Kenrick has developed a recombinant squid suckerin-spider silk fusion protein with cell-adhesion motifs capable of thermal gelation at physiological temperatures without using any chemical cross-linking. Stem cell secretome therapy is a treatment used to modulate the microenvironment of chronic wounds via supplementation with anti-inflammatory/growth factors. However, there is a need to develop better secretome delivery systems that are fully biocompatible and that can encapsulate and release the secretome in a sustained manner. The protein hydrogels developed in this study fulfill all these criteria, forming hydrogels by simple thermal gelation with concomitant encapsulation and subsequent controlled release of the stem cell secretome. Studies on diabetic mice with chronic wounds with the secretome-laden hydrogel demostrated increased wound closure, presence of endothelial cells, granulation wound tissue thickness, and reduced inflammation with no fibrotic scar formation.

22 June 2022

Interplay Between Interfacial Energy, Contact Mechanics, and Capillary Forces in EGaIn Droplets

Publications

Our paper “Interplay Between Interfacial Energy, Contact Mechanics, and Capillary Forces in EGaIn Droplets” is published in “ACS Applied Materials & Interfaces”. In this work in collaboration with Prof. Christian Nijhuis from the University of Twente, former BBML member Shahrouz Amini has investigated the adhesive and contact mechanics behavior of Eutectic gallium−indium (EGaIn), a material extensively used as an interfacial conductor in molecular electronics and wearable healthcare. The study focused on the use of depth-sensing nano-indentation to uncover howe changes in EGaIn/substrate interfacial energies regulate the adhesive and contact mechanic behaviors of EGaIn. Varying the interfacial energy by subjecting EGaIn to different chemical environments and by functionalizing the tip with chemically distinct self-assembled monolayers, we have shown that the adhesion forces between EGaIn and the solid substrate can be increased by up to 2 orders of magnitude. The study also reveals that charge transport rates, the resistance of monolayers, and the contact interactions between EGaIn and monolayers from electrical characterizations are governed by the interfacial energies between substrates and EGaIn.

18 May 2022

Complete Sequences of the Velvet Worm Slime Proteins Reveal that Slime Formation is Enabled by Disulfide Bonds and Intrinsically Disordered Regions

Publications

Our paper “Complete Sequences of the Velvet Worm Slime Proteins Reveal that Slime Formation is Enabled by Disulfide Bonds and Intrinsically Disordered Regions” is published in “Advanced Science”. In this paper, co-first authors and BBML research fellows Lu Yang and Bhargy Sharma have unveiled for the first time the complete sequence of the main velvet worm slime proteins. The slime of velvet worm is a strong and fully biodegradable protein material that undergoes a fast liquid-to-solid transition to ensnare prey. Combining transcriptomic and proteomic studies, we have sequenced the main slime proteins and identified key features for slime self-assembly. The high molecular weight slime proteins contain cysteine residues at the N- and C-termini that mediate the formation of multi-protein complexes via disulfide bonding. We have also identified low complexity domains in the N-termini of the slime and demonstrated their propensity for liquid-liquid phase separation, which may play a key role in slime biofabrication. The work is an important step toward sustainable fabrication of polymers inspired by the velvet worm slime.

27 April 2022

Cephalopod-Mimetic Tunable Photonic Coatings Assembled from Quasi-Monodispersed Reflectin Nanoparticles

Publications

The paper by BBML PhD student Jun Jie Loke, “Cephalopod-Mimetic Tunable Photonic Coatings Assembled from Quasi-Monodispersed Reflectin Nanoparticles”, is published in “ACS Applied Materials & Interfaces”. In this study, Jun Jie has first sequenced, recombinantly expressed, and purified a new reflectin protein from the green eye reef squid. In squids’ dermis, reflectins self-assemble inside iridophore cells to control camouflage of the animal via a complex structural coloration mechanism. By conjugating the recombinant reflectin with a click chemistry ligand, he was able to produce nanoparticles with tunable size from 170 to 1000 nm with near monodisperse size distribution. The click-chemistry ready reflectin nanoparticles were then immobilized onto substrate, producing photonic structures with tunable structural colors regulated by the average particle size. This work paves the way for the fabrication of bioinspired color-changing coatings that mimic cephalopods’ dynamic camouflage.

9 April 2022

In vivo Liquid-Liquid Protects Amyloidogenic Aggregation-Prone During Overexpression in Escherichia coli

Publications

The study by former BBML Research Fellow Dr. Bartosz Gabryelczyk, “In vivo Liquid-Liquid Protects Amyloidogenic Aggregation-Prone During Overexpression in Escherichia coli”, is published in Protein Science. In this study, Bartosz has shown that fusing an amyloid peptide to a phase-separating region from beak proteins leads to the formation of condensates in E. coli cells, thereby preventing premature amyloid formation. The implications are two-fold: first, liquid-like condensates create a protective environment that prevents or delays amyloid formation inside bacterial cells, and second the method can be used to efficiently produce homogenous amyloid peptides by bacterial expression in E. coli, which is traditionally challenging.

3 February 2022

Phase-Separating Peptides for Direct Cytosolic Delivery and Redox-Activated Release of Macromolecular Therapeutics

Publications

Our paper “Phase-Separating Peptides for Direct Cytosolic Delivery and Redox-Activated Release of Macromolecular Therapeutics” is published in Nature Chemistry. In this study, first author and PhD student Yue Sun has developed a new type of peptides (mimicked after squid beak proteins) that phase-separate to form micro-scale coacervate microdroplets. During the phase-separation process, the droplets can recruit large macromolecules under physiological conditions. The coacervate microdroplets readily cross the cell membrane to enter the cytosol. Owing to the side-chain chemistry of the peptide harboring a di-sulfide bond as well as a self-immolative moiety, the droplets disassemble triggered by endogenic glutathione (GSH). As a result, the cargos are readily delivered in the cytosol and the platform allows to deliver large protein therapeutics, anti-cancer peptides that cannot cross the cell membrane on their own, or mRNAs, opening exciting opportunities for a wide range of intracellular therapies for cancer, neurodegenerative, or immune diseases. The study was conducted in collaboration with the team of Dr. Farid Ghadessy (p53, A*STAR) and Dr. Anthony Partridge from MSD International. Check out also our blog on the genesis of this discovery.

18 January 2022

Cephalopod-Mimetic Tunable Photonic Coatings Assembled from Quasi-Monodispersed Reflectin Nanoparticles

Publications

A new review from BBML “Protein-Based Encapsulation Strategies: Towards Micro- and Nanoscale Carriers with Increases Functionality”, written in collaboration with Dr. Ricardo Ramons, Dr. Julien Bernard and Dr. François Ganachaud from INSA Lyon (France), is published in the open access journal “Small Science. The review highlights protein- and peptide-based carriers used for encapsulation and release of active compounds, such as food and therapeutics.

14 December 2021

Self-assembly of a barnacle cement protein (MrCP20) into adhesive nanofibrils

Publications

Our paper “Self-Assembly of a Barnacle Cement Protein (MrCP20) into Adhesive Nanofibrils with Concomitant Regulation of CaCO3 Polymorphism” is published in “Chemistry of Materials”. In this study in collaboration with Prof. Thierry Azaïs from Sorbonne University in Paris, first author Dr. Harini Mohanram has explored the CaCO3 mineralization pathway regulated by the barnacle cement protein MrCP20. Harini has shown that MrCP20 stabilizes the metastable vaterite polymorphism of CaCO3. At the same time, during the mineralization process MrCP20 self-assembles into adhesive amyloid-like nanofibrils.

1 December 2021

Bioinspired short peptide hydrogel for versatile encapsulation and controlled release of growth factor therapeutics

Publications

Our article “Bioinspired short peptide hydrogel for versatile encapsulation and controlled release of growth factor therapeutics” is published in Acta Biomaterialia. In this study conducted in collaboration with the teams of Prof. Dalton Tay (MSE) and Prof. Andrew Tan (LKC and SBS), first author and Senior Research Fellow Shu Hui Hiew has shown that the short GV8 peptide (only 8 amino acid long) can be used as a simple hydrogel system for controlled release of growth factor and stem cell sectrome mixtures for wound healing applications. GV8 hydrogel benefits from many advantages over other hydrogel systems used for similar wound healing and topical applications, including a simple on-pot gelation procedure and versatility to encapsulate and deliver macromolecular therapeutics. This peptide thus represents a promising biomaterial for regenerative medicine applications.

1 September 2021

Bioinspired functionally graded composite assembled using cellulose nanocrystals and genetically engineered proteins

Publications

The manuscript “Bioinspired Functionally Graded Composite Assembled Using Cellulose Nanocrystals and Genetically Engineered Proteins with Controlled Biomineralization” led by our collaborator Dr. Pezhman Mohammadi from VTT Research Center in Finland is published in “Advanced Materials”. Inspired by the impact-resistant dactyl club of the stomatopod, Pezhman has rationally designed and synthesized a mineralized biocomposite exhibiting high strength, stiffness, and fracture toughness. This material is made of an expanded helicoidal organization of cellulose nanocrystals (CNCs) mixed with genetically engineered proteins that regulate both binding to CNCs and in situ growth of reinforcing apatite crystals.

26 August 2021

Liquid–liquid phase separation of the green mussel adhesive protein Pvfp-5

Publications

Our paper, in collaboration with the labs of Prof. Yu Jing and Prof. Konstantin Pervushin, “Liquid–Liquid Phase Separation of the Green Mussel Adhesive Protein Pvfp-5 is Regulated by the Post-Translated Dopa Amino Acid” is published in Advanced Materials. The study, with Dr. Deepankumar from BBML and PhD student Guo Qi from Prof. Yu Jing’s lab as co-first authors, demonstrates that in the green mussel adhesive protein Pvfp-5, modifying tyrosine amino acid residues into its post-translated version Dopa, enables self-coacervation (liquid-liquid phase separation, LLPS) of the protein. The main conclusion of this study is the suggestion that Dopa plays an important role in regulating LLPS of mussel adhesive proteins, which may be critical to concentrate the adhesive proteins at the plaque/substrate interface.

9 June 2021

Liquid–liquid phase separation of short histidine-and tyrosine-rich peptides

Publications

Our manuscript in collaboration with Prof. Konstantin Pervushin’s lab “Liquid–Liquid Phase Separation of Short Histidine-and Tyrosine-Rich Peptides: Sequence Specificity and Molecular Topology” is published in a special issue of “The Journal of Physical Chemistry B” on Liquid-Liquid Phase Separation (LLPS)”. In this paper, first author and PhD student Jessica Lim has used short histidine and tyrosine-rich model peptides to precisely assess the roles of peptide motifs and single residues on the phase behavior of microdroplets obtained by LLPS. We have found that His and Tyr residues located near the sequence termini drive phase separation, forming interaction nodes that stabilize microdroplets. Combining quantum chemistry simulations with NMR studies, we also predict atomic-level bond geometries and uncover inter-residue supramolecular interactions governing LLPS. These results suggest that these phase-separating peptides are arranged into topological networks, which upon expansion form mesoscopic three-dimensional networks of microdroplets.

1 June 2021

Structure of a consensus chitin-binding domain revealed by solution NMR

Publications

Our paper “Structure of a consensus chitin-binding domain revealed by solution NMR” is published in The Journal of Structural Biology. In this study, PhD student Dario Heyman and Dr. Harini Heyman have revealed the 3D structure of a chitin-binding domain (CBD-γ) located in a chitin-binding protein (CBP) from the beak of the jumbo squid Dosidicus gigas. This protein is one of four CBPs identified in the beak mouthpart of D. gigas and interacts with chitin to form a scaffold network that is infiltrated with a second set of structural proteins during beak maturation. We used solution state NMR spectroscopy to elucidate the molecular interactions between CBD-γ and the soluble chitin derivative pentaacetyl-chitopentaose (PCP) and found that folding of CBD-γ is triggered by its interaction with PCP.

3 May 2021

Nanocapsules produced by nanoprecipitation of designed suckerin-silk fusion proteins

Publications

In collaboration with Dr. Julien Bernard and Dr. François Ganachaud from INSA Lyon (France), we have developed a new type of protein-based nanocapsules by the nanoprecipitation method. The paper “Nanocapsules produced by nanoprecipitation of designed suckerin-silk fusion proteins” is published in ACS MacroLetters and reports the first example of a recombinant protein specifically designed for the nanoprecipitation process.

1 May 2021

Fracture toughness of the stomatopod dactyl club

Publications

Our paper “Fracture toughness of the stomatopod dactyl club is enhanced by plastic dissipation: A fracture micromechanics study” is published in Acta Biomaterialia. In this study, PhD student Isaiah Chua has conducted a micromechanics study of the dactyl club of mantis shrimps. He has used Focus Ion Beam (FIB) to machine microcantilever specimens with chevron-notched crack geometry to assess the fracture toughness. Adopting linear elastic and elastic-plastic fracture mechanics protocols, this study quantitatively demonstrates for the first time that plastic dissipation is the major contribution to the fracture response of the hypermineralized impact region of the dactyl club.

13 October 2020

Mimicking mineralization and adhesion dynamics in barnacle cement protein

Publications

Our new paper on barnacle cement protein, “Disorder–Order Interplay of a Barnacle Cement Protein Triggered by Interactions with Calcium and Carbonate Ions: A Molecular Dynamics Study”, is published in the ACS journal “Chemistry of Materials”. In this work, first author Akshita Kumar has conducted highly-detailed Molecular Dynamics (MD) simulations to unveil the molecular-level interactions between the barnacle cement protein MrCP20 and calcium carbonate, both in ionic form and on solid surfaces. MrCP20 is one of the key protein in the barnacle cement that secures firm attachment of the animal to solid immersed surfaces, including minerals such as calcite. It has also previously been suggested to be involved in the biomineralization (calcification) of the protective barnacle shells but molecular details were previously unknown. Exploiting the 3D structure of MrCP20 previously elucidated in our lab, Akshita was able to precisely identify how MrCP20 captures calcium and carbonate ions around its surface, which is the first critical step towards protein-regulated biomineralization. She also identified the intermolecular interactions allowing MrCP20 to strongly and irreversibly adhere to calcified surfaces as calcite or hydroxyapatite. MrCP20 turns out to be a multifunctional protein of the barnacle cement that regulates biomineralization and contributes to the strong water-resistant adhesion of barnacles.

6 October 2020

Next-gen biocide-free, fouling resistant coatings

Publications

A few years ago, in a paper published in, “Science”, we demonstrated that Slippery-Liquid Infused Surfaces (SLIPS) are remarkably efficient to prevent marine biofouling and unveiled the mechanisms by which marine mussels were deterred from attaching to such surfaces. Since then, we have established a collaboration with “Adaptive Surface Technology”, a spin-off company who has been developing SLIPS coatings for various applications, including to combat marine biofouling. In our new publication “Laboratory and Field Testing Assessment of Next Generation Biocide-Free, Fouling-Resistant Slippery Coatings”, published in the journal ACS Applied Polymer Materials , first-author Snehasish Basu from BBML has conducted a comprehensive study to assess the performance of AST coatings both in the lab and in the field. Using our in-house developed testing protocols, we have found that these coatings can perform at least as well as the lab-scale SLIPS versions. We also tested these coatings in the field in the highly aggressive fouling waters of Singapore. Fouling species, both soft biofilms as well as hard macrofoulers, could be easily detached from the surfaces, which has useful practical implications because it means much less labor-intensive procedures to clean up fouled surfaces. The work has also confirmed our previous fundamental findings established in lab-scale studies: the thickness of the lubricant overlayer is a critical design criterion that largely controls the fouling-release performance of SLIPPERY coatings.

15 July 2020

Barnacle cement protein induces corrosion

Publications

Fouling organisms not only stick to immersed structures but can also cause serious corrosion damage. Barnacles in particular are well-known to corrode marine-grade steels, but so far the corrosion mechanism has remained elusive. In a joint collaboration with the lab of Prof. Matteo Seita at MAE/NTU, we have demonstrated that one of the main cement protein in the cement complex of barnacles (MrCP20) is redox-active and can directly oxidize iron. In our paper “Accelerated corrosion of marine-grade steel by a redox-active, cysteine-rich barnacle cement protein”, published in "npj Materials Degradation", we have shown that di-sulfide bonds stabilizing MrCP20 are reduced upon adsorbing onto steel surfaces, thereby oxidizing metallic Fe into Fe ions. This mechanism, identified for the first time in a protein/metal interface, may have also be involved in protein-induced degradation of other metallic surfaces such as biomedical implants.

15 May 2020

Magnetically responsive peptide coacervates for intracellular drug release

Publications

Our publication “Magnetically responsive peptide coacervates for dual hyperthermia and chemotherapy treatments of liver cancer” has been published in “Acta Biomaterialia”. Peptide coacervates derived from squid beak proteins (previously discovered in our lab) hold great potential to efficiently package various therapeutics and release them “on-demand” using an external stimulus or an internally-encoded trigger. In this work, Zhi Wei from BBML, in collaboration with the research team of Prof. Raju Ramanujan at NTU/MSE, has managed to recruit both the anti-cancer drug doxorubicin (Dox) and iron oxide magnetic nanoparticles (MNPs) within the peptide coacervates. Using an external magnetic field, the MNPs induced localized heating within the droplets, in turn leading to their disassembly and to the release of the drugs. The concept was demonstrated in vitro on liver cancer cell lines: nearly 100% cell death could be induced by applying an external magnetic field. An exciting development was that the coacervates microdroplets could penetrate the cell membrane through an endocytosis-free pathway, opening the door to a wide range of intracellular drug release. Stay tuned for future developments in this direction!

24 February 2020

Suckerin adhesives and anti-fouling coatings

Publications

Two new publications from the BBML were recently published. The article “Supramolecular β-Sheet Suckerin–Based Underwater Adhesives” appeared in “Advanced Functional Materials" and is the result of a collaboration with the labs of Dr. Bruno Zappone (Italian National Research Center and the University of Calabria) and Prof. Dong-Soo Hwang (POSTECH, South Korea). In this work, Deepankumar Kanagavel from BBML has developed artificial protein adhesives from squid sucker teeth proteins (SRTs) exhibiting outstanding water-resistant adhesive properties, and demonstrated that strong adhesion was due to supramolecular cross β-sheet motifs. The other paper, "Green biolubricant infused slippery surfaces to combat marine biofouling", by Snehasish Basu is in the area of marine biofouling and was published in the “Journal of Colloids and Interface”. In this study, which is a follow-up study of our previous article that appeared in “Science” two years ago, we have modified anti-fouling slippery coatings by replacing the silicon lubricant phase with the eco-friendly biolubricants oleic acid and methyl oleate that are harmless for the marine environment. In the lab, we have obtained a fouling-resistance performance nearly as equivalent as silicon-oil infused SLIPS coatings.

29 November 2019

LLPS of Squid Beak Peptides

Publications

A new paper by BBML, in collaboration with the lab of Prof. Konstantin Pervushin at SBS/NTU, just appeared in “Nature Communications”. In the article “Hydrogen bond guidance and aromatic stacking drive liquid-liquid phase separation of intrinsically disordered histidine-rich peptides” first author Bartosz Gabryelczyk (now back at Aalto University in Finland) has revealed the key molecular mechanisms driving the Liquid-Liquid Phase Separation (LLPS) of a family of Histidine-rich and Tyrosine-rich peptides from squid beak proteins. Using in particular mutagenesis and protein NMR, we have identified tandem repeats governing LLPS in this family of intrinsically-disordered peptides, and demonstrated that hydrogen bonding between Histidine and Tyrosine side-chains plays a critical role in the cascade leading to LLPS. In addition to fundamental understanding of molecular interactions driving LLPS, the work provides guidelines to rationally design pH-responsive microdroplets for smart drug delivery applications.

28 October 2019

3D structure of barnacle cement protein using solution NMR

Publications

Our article “Three-dimensional structure of Megabalanus rosa Cement Protein 20 revealed by multi-dimensional NMR and molecular dynamics simulations” is published in a theme issue of the Philosophical Transactions B entitled: “Transdisciplinary approaches to the study of adhesion and adhesives in biological systems”. In this study, first author Harini Mohanram unveiled the 3D structure of the cement protein from the M. rosa barnacle CP20 using solution NMR. Barnacles secrete a strong wet-resistant adhesive and CP20 is a major component of this proteinaceous-cement. The work is significant because it has largely been assumed that such functional adhesive proteins are fully disordered, an assumption challenged by the structural determination of CP20. Indeed, this is the first report describing the tertiary structure of an extracellular biological adhesive protein at the molecular level.

10 September 2019

Suckerin Peptide Hydrogel Induced by 3₁₀-Helices to β-Sheet Transition in Water

Publications

Our paper “A Short Peptide Hydrogel with High Stiffness Induced by 3₁₀-Helices to β-Sheet Transition in Water” is published in “Advanced Science”, with Shui Hui Hiew and Harini Mohanram as main contributors from BBML. Other collaborators include Profs. Konstantin Pervushin and Yugang Mu from SBS and Prof. Raffaele Mezzenga from ETH Zürich. In this study, we have discovered that a short, 8 amino-acid long peptide abundantly present in sucker ring teeth proteins can form stiff hydrogels by simple gelation in water without using any chemical modification or organic solvent. Using solution and solid-state NMR, we have shown that the peptide initially forms unusual right-handed 3₁₀ helices (which have never been reported before for a short peptide). Gelation occurs by a 3₁₀ helices to β-sheet conformation transition. The biocompatibility, low immunogenicity as well as ease of gelation in water makes this peptide hydrogel a promising candidate for various biomedical applications.

15 April 2019

Time-Resolved Observations of LLPS at the Nanoscale Using in Situ Liquid TEM

Publications

Our paper on the use of liquid-cell Transmission Electron Microscopy (liquid TEM) to study liquid-liquid phase separation (LLPS) is published in the “Journal of the American Chemical Society” (JACS). In this study entitled “Time-Resolved Observations of Liquid−Liquid Phase Separation at the Nanoscale Using in Situ Liquid Transmission Electron Microscopy”, Dr. Hortense Le Ferrand in close collaboration with our collaborator Prof. Martial Duchamp has used liquid cell TEM to observe for the first time nucleation events of protein-based LLPS at the nanoscale with millisecond time resolution. The work opens a wide range of opportunities in the rapidly growing area of LLPS, including membraneless organelles or pathological diseases triggered by LLPS.

11 April 2019

Mineralization Process of the Tough Mantis Shrimp Dactyl Club

Publications

A new paper by BBML is published in the Proceedings of the National Academy of Science of the United States of America (PNAS). In this paper entitled “A diecast mineralization process forms the tough mantis shrimp dactyl club”, first author Dr. Shahrouz Amini (currently at the Max-Planck Institute for Colloids and Interfaces in Potsdam, Germany) and colleagues have unveiled the growth of the entire ultra-tough dactyl club of the mantis shrimp, a model system which we have been investigating since 2010. The study exploits the fact that mantis shrimps, as crustaceans, regularly molt their entire exoskeletons (including the dactyl club), providing a unique opportunity to monitor the growth of entire complex hard tissues. Thus, by maintaining live specimens in our aquaria mantis shrimps represent an ideal model organism to study biomineralization. In the study, we also identified the main protein regulating apatite formation in the dactyl club by assembling a transcriptome of the dactyl club tissue and probing it with proteomic data of the macromolecular template that controls the club biomineralization. Congrats to Shahrouz and all other BBML members for this excellent achievement!

12 February 2019

Double-Layer Mechanochromic Hydrogel with Multidirectional Force Sensing and Encryption Capability

Publications

A new paper by BBML, “A Double-Layer Mechanochromic Hydrogel with Multidirectional Force Sensing and Encryption Capability” is published in Advanced Functional Materials. The work by Dr. Qingi Zhu was in close collaboration with Profs. Prof. Niels Holten-Andersen and Krystyn Van Vliet from the Department of Materials Science at MIT. Qingdi developed robust double-layer hydrogels that display remarkable mechanochromic ability over a wide range of strain up to 300% deformation. The hydrogel is based on a double-layer concept, with each layer containing luminescent species (lanthanide ions and carbon dots) exhibiting overlapped absorption spectra but distinct emission spectra. The work also demonstrates proof-of-concept applications of the hydrogel as pressure and contact force sensors as well as its potential to be used for encryption devices

26 October 2018

Biomechanical design of the saddle-shaped spring of the stomatopod dactyl club

Publications

Our paper on the biomechanical design of the saddle-shaped spring of the stomatopod dactyl club just got published in iScience from Cell Press and gathered multiple media coverage. In this work, first author Maryam Tadayon from our lab has demonstrated how the saddle of the mantis shrimp dactyl club can store a high density of elastic energy in order to power the ultra-fast strike of the dactyl club. The saddle is a bi-layer structure, with one layer ceramic-based to store a high density of elastic energy and the other layer containing a higher content of biopolymers to prevent brittle fracture of the saddle. The paper was featured, among others, in Wired Magazine, iflscience; and Chemistry World. Check out also the didactic video on the iScience youtube channel.

15 July 2018

Suckerin protein NMR and Squid Beak Protein Coacervates

Publications

Two publications from BBML were recently published. In their paper Supramolecular propensity of suckerin proteins is driven by β-sheets and aromatic interactions published in “Biomaterials Science”, Dr. Akshita Kumar and Dr. Harini Mohanram have precisely demonstrated using protein NMR which domains of suckerin proteins (previously discovered and sequenced in our lab) adopt anti-parallel beta-sheets. They have also shown that suckerins are further stabilized by pi-pi stacking of aromatic residues, providing design guidelines to artificially produce suckerin-like proteins exhibiting similar mechanical properties. And in his paper Glucose-Responsive Peptide Coacervates with High Encapsulation Efficiency for Controlled Release of Insulin published in “Bioconjugate Chemistry”, Zhi Wei Lim has exploited modular peptides from squid beak proteins (previously discovered and sequenced in our lab) to produce coacervate micro-droplets that can encapsulate both insulin and glucose oxidase with extreme high efficiency, with a very simple coacervation process. The micro-droplets are pH sensitive: upon exposure to glucose, glucose oxidase transforms glucose into gluconic acid, thereby locally decreasing pH and triggering the disassembly of micro-droplets and the release of insulin. Therefore, the micro-droplets mimic this glucose responsiveness function of pancreatic β-cell by releasing insulin according to glucose levels. Congrats all for these great publications.

26 February 2018

White Light-Emitting Multistimuli-Responsive Hydrogels

Publications

Our paper “White Light-Emitting Multistimuli-Responsive Hydrogels with Lanthanides and Carbon Dots” in collaboration with the labs of Prof. Niels Holten-Andersen and Prof. Krstyn Van Vliet from the Department of Materials Science at MIT is published in "ACS Applied Materials & Interfaces". In this work, supported by a seed grant from the BioSym program of the Singapore-MIT Research Alliance for Research and Technology (SMART), first author Dr. Qingdi Zhu from BBML developed a new type of luminescent hydrogel with white-light emission and responsiveness against multiple stimuli, allowing to sense temperature, pH, organic solvents, or metal ions with one single material and under hydrated conditions. Congrats to Qingdi for this excellent achievement.

18 August 2017

Preventing Mussel Adhesion using Lubricant-Infused Materials

Publications

Our paper "Preventing Mussel Adhesion using Lubricant-Infused Materials" is published in "Science". The work was a close collaboration with the lab of Joanna Aizenberg from the Wyss Institute for Biologically-Inspired Engeering at Harvard University and demonstrates that lubricant-infused materials developed by the Aizenberg’s lab are extremely efficient both at deterring mussel adhesion and at minimising the adhesion strength of mussel threads. Authors from BBML were Shahrouz Amini, Luigi Petrone (both co-first authors) Clarinda Sutanto, and Ali Miserez (co-corresponding author).

09 November 2015

The Mantis Shrimp Saddle: A Biological Spring Combining Stiffness and Flexibility

Publications

Our paper "The Mantis Shrimp Saddle: A Biological Spring Combining Stiffness and Flexibility" is on the front cover of “Advanced Functional Materials”. Congratulations to Maryam Tadayon, first author of the paper and Shahrouz Amini, co-author on this work.

28 October 2015

Mussel adhesion is dictated by time-regulated secretion and molecular conformation of mussel adhesive proteins

Publications

Our paper entitled “Mussel adhesion is dictated by time-regulated secretion and molecular conformation of mussel adhesive proteins” appeared today in “Nature Communications”. In this work, we have shown that adhesive proteins secreted by the green mussel to stick to solid substrates is precisely orchestrated, with the the protein Pvfp-5 always secreted first and playing the role as a primer that removes surface water for subsequent tight adhesion. We have also obtained for the first time the tertiary structure of mussel adhesive proteins by homology modelling and molecular dynamics simulations. Members of BBML on this work were first-author Luigi Petrone, co-authors Akshita Kumar, Clarinda Sutanto, Shahrouz Amini, and corresponding author Ali Miserez. This work was a close collaboration with the groups of Chandra Verma at the Bioinformatics Institute at A*Star and Dr. Bruno Zappone from the Italian National Research Council.

21 September 2015

Multi-scale thermal stability of a hard thermoplastic protein-based material

Publications

A manuscript entitled "Multi-scale thermal stability of a hard thermoplastic protein-based material" co-led by the BBML and by Dr. Admir Masic from the Max Planck Institute for Colloids and Interfaces appeared today in “Nature Communications”. In this work, we have demonstrated for the first time the potential of the “Squid Sucker Ring Teeth (SRT)” –previously discovered in our lab– to be used as a thermoplastic biopolymer for 3D printing applications. A unique property of SRT is their fully thermo-plastic behaviour, a characteristic which is very uncommon in biopolymers. In collaboration with our colleagues from the Wyss Institute for Bioinspired Engineering at Harvard (James Weaver) and the MIT media lab (Steven Keating and Neri Oxman), we have demonstrated that SRT can be used a recylable biopolymer that can be re-used multiple times during additive manufacturing. We have also elucidated the fundamental structural features, across multiple length scales, responsible for the thermoplastic behaviour of SRT using temperature resolved Small Angle X-ray Scattering, Wide-Angle X-ray Scattering, and Fourier Transform Infrared Spectroscopy. The work opens up many interesting possibilities to develop SRT-based biopolymers as eco-friendly materials in additive manufacturing applications.

08 June 2015

Contact damage tolerance of the stomatopod dactyl club and Infiltration of chitin by protein coacervates in squid beak

Publications

Two papers from the BBML are appearing on-line today, one in "Nature Materials" and one in Nature Chemical Biology. In the paper appearing in "Nature Materials", entitled “The role of quasi-plasticity in the extreme contact damage tolerance of the stomatopod dactyl club", authored by Shahrouz Amini, Maryam Tadayon, and Ali Miserez from the BBML and Prof. Sridhar Idapalapati from MAE, we have unveiled key mechanisms that endow mantis shrimps’ dactyl clubs with their remarkable impact damage tolerance. Using comprehensive nano- and micro-contact mechanics studies, combined with Raman spectroscopy, we have shown that the impact surface of dactyl clubs exhibit a quasi-plastic contact mechanics response, which is key in absorbing impact energy. We have also shown that the inner layers of the dactyl club strain-harden under contact load, which further enhances the damage tolerance against impact.

The second paper appearing today in "Nature Chemical Biology", entitled “Infiltration of chitin by protein coacervates defines the squid beak mechanical gradient" is the result from a close collaboration with the group of Prof. Herb Waite at UCSB (Dr. YerPeng Tan and Dr. Wei Wei) and the Molecular Engineering Lab/A*Star (MEL, Dr. Shawn Hoon), with Paul Guerette, Cai Hao, Ali Ghadban, and Ali Miserez as contributors from the BBML. In this work, we have first sequenced all major beak proteins that make up the robust squid beak. We have shown that the beak is comprised of 2 major protein families, namely Dosidicus gigas Chitin-Binding Proteins (DgCBPs) and D. gigas His-rich Proteins (DgHBPs). Next, we have demonstrated that DgHBPs form so-called “coacervates”, which is key in the bioprocessing of this remarkable graded structure. This study demonstrates for the first time that protein coacervates play a central role during the processing of chitin/protein bulk biocomposites. According to our study, this phenomenon could be more widely spread in Biology than currently recognised, for instance during the formation of insect exoskeletons (cuticles) or in arthropod fangs (spider and scorpion fangs for instance). Congrats to all for these very thorough studies that spanned over a few years before they finally got published!"

26 May 2015

From Soft Self-Healing Gels to Stiff Films in Suckerin-Based Materials Through Modulation of Crosslink Density and β-Sheet Content

Publications

Congratulations to Dawei Ding and other BBML group members (Paul Guerette, Fu Jing, Lihong Zhang) for the publication of his paper entitled “From Soft Self-Healing Gels to Stiff Films in Suckerin-Based Materials Through Modulation of Crosslink Density and β-Sheet Content” in "Advanced Materials". In this work, we have used our recently discovered “suckerin” proteins to prepare biomaterials spanning 7-orders of magnitude of elasticity, from soft hydrogels to very stiff films. We have exploited the unique di-block, co-polymer-like primary structure and Di-Tyrosine cross-linking chemistry to vary the stiffness of suckerin-based materials. We have also shown the excellent biocompatibility of suckerin materials, and this work opens a wide range of possibilities to use suckerins in biomedical applications.

09 June 2014

Nanoconfined β‐Sheets Mechanically Reinforce the Supra-Biomolecular Network of Robust Squid Sucker Ring Teeth

Publications

Our paper “Nanoconfined β‐Sheets Mechanically Reinforce the Supra-Biomolecular Network of Robust Squid Sucker Ring Teeth” is published in "ACS Nano".

This work is the culmination of our recent efforts to understand the intriguing sucker ring teeth (SRT), located on the tentacles and arms of cephalopods (squids and cuttlefish). SRT exhibit hard tissues-like mechanical properties, yet are completely non-mineralised and do not contain metal ions either. Instead, they are completely protein-based, and perhaps even more fascinating covalent cross-links between the protein chains are also absent. Thus, SRT are essentially giant supramolecular networks that are thermoplastic-like, a property which is unprecedented in other biological hard tissues and very useful in order to reshape the material at will by simple thermal activation.

The paper main conclusion are three fold. First, we have demonstrated that SRT are made of a protein family –called “suckerins"– with extreme modular design: the entire teeth is a protein complex made of 10 to 20 (depending on the species) highly related proteins, with most of them containing silk-like domains. Second, using a phylogenetic analysis of the modular proteins, we have shown that suckerin are encoded by an ancient gene family which is ~ 350 Millions years old. Third, the work shows that the major contribution to mechanical reinforcement are nanoconfined β-sheets of precise nano-scale dimensions that are optimised for mechanical strengthening. The size of the nanoconfined β-sheets is precisely encoded by the regular placement of Proline residues in suckerin proteins, which act as precise β-sheet breakers.

The work provides an extensive molecular toolbox for molecular biomimcry, using either the full-length suckerin sequences we have discovered or their smaller modular peptidic building blocks that could be exploited in various self-assembly strategies. Collaborators on this work include colleagues at MEL lab/A*STAR (Dr. Shawn Hoon), the Max Planck Institute for Colloids and Interfaces (Dr. Admir Masic), the Wyss Institute for Bioinspired Engineering at Harvard (Dr. James Weaver), and the Institute of Molecular and Cell Biology at A*STAR (Dr. Byrappa Venkatesh and Dr. Vydianathan Ravi).

30 Jan 2014

Textured fluorapatite bonded to calcium sulphate strengthen stomatopod raptorial appendages

Publications

Our paper “Textured fluorapatite bonded to calcium sulphate strengthen stomatopod raptorial appendages” has been published in “Nature Communications” and is being highlighted as a featured paper on the website of Nature Communications. The work was carried out in collaboration with our colleagues Dr. Admir Masic and Dr. Luca Bertinetti from the Max Planck Institute for Colloids and Interfaces, and with the group of Prof. Haibin Su at MSE. Congrats to Shahrouz, first author of this paper, for his excellent work!

09 October 2013

Cover of Nature Biotechnology

Publications

Our paper "Accelerating the Design of Biomimetic Materials by Integrating RNA-seq with Proteomics and Materials Science is on the cover of "Nature Biotechnology"!

09 September 2013

Accelerating the Design of Biomimetic Materials by Integrating RNA-seq, Proteomics, and Materials Science

Publications

Our paper "Accelerating the Design of Biomimetic Materials by Integrating RNA-seq, Proteomics, and Materials Science" has just been published in "Nature Biotechnology", with Paul Guerette, Shahrouz Amini, Gavin Tay, Dawei Ding, and Ali Miserez as authors from the BBML. This work, in close collaboration with the Molecular Engineering Lab (MEL) at A*Star, explores for the first time the usage of high throughput RNA-sequencing for biological materials. By fully integrating RNA-seq with protemics and materials characterization, we have demonstrated that protein sequences of any model system of interest can be obtained in just a few weeks or months.

05 March 2013

Phase transition-induced elasticity of alpha-helical bioelastomeric fibres and networks

Publications

A paper from the BBML is on the inside cover of "Chemical Society Review (7th March 2013)". The paper by Ali Miserez and Paul Guerette is entitled "Phase transition-induced elasticity of alpha-helical bioelastomeric fibres and networks".

08 June 2012

The Stomatopod Dactyl Club: A Formidable Damage-Tolerant Biological Hammer

Publications

A paper entitled "The Stomatopod Dactyl Club: A Formidable Damage-Tolerant Biological Hammer" with BBML as a main collaborator has been published in"Science". Asst. Prof. Ali Miserez is one of the Co-First Authors of the paper led by our collaborator Dr. James Weaver from Harvard University, with other partnerships from UC Riverside, Purdue University, and Brookhaven National Laboratory. The paper is also highlighted in "Perspectives".

03 December 2010

Cross-linking Chemistry of Squid Beak

Publications

A paper from the BBML is on the cover of the December 3, 2010 issue of "The Journal of Biological Chemistry". The paper, entitled "Cross-linking Chemistry of Squid Beak" was written in collaboration with Prof. Herbert Waite at UC Santa Barbara and with Mr. Daniel Rubin, a graduate student at Harvard University.