An Overview on the Adhesion Mechanisms of Typical Aquatic Organisms and the Applications of Biomimetic Adhesives in Aquatic Environments

Water molecules pose a significant obstacle to conventional adhesive materials. Nevertheless, some marine organisms can secrete bioadhesives with remarkable adhesion properties. For instance, mussels resist sea waves using byssal threads, sandcastle worms secrete sandcastle glue to construct shelters, and barnacles adhere to various surfaces using their barnacle cement. This work initially elucidates the process of underwater adhesion and the microstructure of bioadhesives in these three exemplary marine organisms. The formation of bioadhesive microstructures is intimately related to the aquatic environment. Subsequently, the adhesion mechanisms employed by mussel byssal threads, sandcastle glue, and barnacle cement are demonstrated at the molecular level. The comprehension of adhesion mechanisms has promoted various biomimetic adhesive systems: DOPA-based biomimetic adhesives inspired by the chemical composition of mussel byssal proteins; polyelectrolyte hydrogels enlightened by sandcastle glue and phase transitions; and novel biomimetic adhesives derived from the multiple interactions and nanofiber-like structures within barnacle cement. Underwater biomimetic adhesion continues to encounter multifaceted challenges despite notable advancements. Hence, this work examines the current challenges confronting underwater biomimetic adhesion in the last part, which provides novel perspectives and directions for future research.

Genetically Programmed Temperature-Responsive Barnacle-Derived Protein with an Enhanced Adhesion Ability

There is an emerging strong demand for smart environmentally responsive protein-based biomaterials with improved adhesion properties, especially underwater adhesion for potential environmental and medical applications. Based on the fusion of elastin-like polypeptides (ELPs), SpyCatcher and SpyTag modules, biosynthetic barnacle-derived protein was genetically engineered and self-assembled with an enhanced adhesion ability and temperature response. The water resistance ability of the synthetic protein biopolymer with a network structure increased to 98.8 from 58.5% of the original Cp19k, and the nonaqueous adhesion strength enhanced to 1.26 from 0.68 MPa of Cp19k. The biopolymer showed an improved adhesion ability toward hydrophilic and hydrophobic surfaces as well as diatomite powders. The combination of functional module ELPs and SpyTag/SpyCatcher could endow the biosynthetic protein with temperature response, an insoluble form above 42 °C and a soluble form at 4 °C. The combinational advantages including temperature response and adhesion performance make the self-assembled protein an excellent candidate in surgical adhesion, underwater repair, and surface modification of various coatings. Distinct from the traditional approach of utilizing solely ELPs, the integration of short ELPs with Spy partners exhibited a synergistic enhancement in the temperature response. The synergistic effects of two functional modules provide a technical method and insight for designing smart self-assembled protein-based biopolymers.

Mussel-inspired protein-based nanoparticles for curcumin encapsulation and promoting antitumor efficiency

Curcumin demonstrated therapeutic potential for cancer. However, its medical application is limited due to low solubility, poor stability and low absorption rate. Here, we used the mussel-inspired functional protein (MPKE) to fabricate the curcumin-carrying nanoparticle (Cur-MPKE) for encapsulating and delivering curcumin. The protein MPKE is composed of the mussel module and zwitterionic peptide. The Dopa group bonding characteristic of the mussel module was leveraged for the self-assembly of nanoparticles, while the superhydrophilic property of the zwitterionic peptide was utilized to enhance the stability of nanoparticles. As expected, MPKE and Cur are tightly bound through hydrogen bonds and dynamic imide bonds to form nanoparticles. Cur-MPKE showed improved solubility and stability in aqueous solutions as well as excellent biocompatibility. Besides, Cur-MPKE also exhibited pH-triggered release and enhanced uptake of curcumin by tumor cells, promoting the antioxidant activity and antitumor effect of curcumin. Moreover, systemic experiments of Cur-MPKE to rats demonstrated that Cur-MPKE significantly inhibited tumor tissue growth and proliferation without causing obvious systemic toxicity. This work provides a new strategy for fabricating the delivery system of curcumin with improved stability, sustainability and bioavailability.

Alternative strategies for the recombinant synthesis, DOPA modification and analysis of mussel foot proteins - A case study for Mefp-3 from Mytilus edulis

Mussel foot proteins (Mfps) possess unique binding properties to various surfaces due to the presence of L-3,4-dihydroxyphenylalanine (DOPA). Mytilus edulis foot protein-3 (Mefp-3) is one of several proteins in the byssal adhesive plaque. Its localization at the plaque-substrate interface approved that Mefp-3 plays a key role in adhesion. Therefore, the protein is suitable for the development of innovative bio-based binders. However, recombinant Mfp-3s are mainly purified from inclusion bodies under denaturing conditions. Here, we describe a robust and reproducible protocol for obtaining soluble and tag-free Mefp-3 using the SUMO-fusion technology. Additionally, a microbial tyrosinase from Verrucomicrobium spinosum was used for the in vitro hydroxylation of peptide-bound tyrosines in Mefp-3 for the first time. The highly hydroxylated Mefp-3, confirmed by MALDI-TOF-MS, exhibited excellent adhesive properties comparable to a commercial glue. These results demonstrate a concerted and simplified high yield production process for recombinant soluble and tag-free Mfp3-based proteins with on demand DOPA modification.

Artificial structural proteins: Synthesis, assembly and material applications

Structural proteins have evolved over billions of years and offer outstanding mechanical properties, such as resilience, toughness and stiffness. Advances in modular protein engineering, polypeptide modification, and synthetic biology have led to the development of novel biomimetic structural proteins to perform in biomedical and military fields. However, the development of customized structural proteins and assemblies with superior performance remains a major challenge, due to the inherent limitations of biosynthesis, difficulty in mimicking the complexed macroscale assembly, etc. This review summarizes the approaches for the design and production of biomimetic structural proteins, and their chemical modifications for multiscale assembly. Furthermore, we discuss the function tailoring and current applications of biomimetic structural protein assemblies. A perspective of future research is to reveal how the mechanical properties are encoded in the sequences and conformations. This review, therefore, provides an important reference for the development of structural proteins-mimetics from replication of nature to even outperforming nature.

Nature-Inspired Wet Drug Delivery Platforms

Nature has created various organisms with unique chemical components and multi-scale structures (e.g., foot proteins, toe pads, suckers, setose gill lamellae) to achieve wet adhesion functions to adapt to their complex living environments. These organisms can provide inspirations for designing wet adhesives with mediated drug release behaviors in target locations of biological surfaces. They exhibit conformal and enhanced wet adhesion, addressing the bottleneck of weaker tissue interface adhesion in the presence of body fluids. Herein, it is focused on the research progress of different wet adhesion and bioinspired fabrications, including adhesive protein-based adhesion and inspired adhesives (e.g., mussel adhesion); capillarity and Stefan adhesion and inspired adhesive surfaces (e.g., tree frog adhesion); suction-based adhesion and inspired suckers (e.g., octopus' adhesion); interlocking and friction-based adhesion and potential inspirations (e.g., mayfly larva and teleost adhesion). Other secreted protein-induced wet adhesion is also reviewed and various suckers for other organisms and their inspirations. Notably, one representative application scenario of these bioinspired wet adhesives is highlighted, where they function as efficient drug delivery platforms on target tissues and/or organs with requirements of both controllable wet adhesion and optimized drug release. Finally, the challenges of these bioinspired wet drug delivery platforms in the future is presented.

A Customizable Proteinic Bioadhesive Patch with Water-Switchable Underwater Adhesiveness, Adjustable Biodegradability, and Modifiable Stretchability for Healing Diverse Internal Wounds

Customizable bioadhesives for individual organ requirements, including tissue type and motion, are essential, especially given the rise in implantable medical device applications demanding adequate underwater adhesion. While synthetic bioadhesives are widely used, their toxicity upon degradation shifts focus to biocompatible natural biomaterials. However, enhancing the adhesive strengths of these biomaterials presents ongoing challenges while accommodating the unique properties of specific organs. To address these issues, three types of customized underwater bioadhesive patches (CUBAPs) with strong, water-responsive adhesion and controllable biodegradability and stretchability based on bioengineered mussel adhesive proteins conjugated with acrylic acid and/or methacrylic acid are proposed. The CUBAP system, although initially nonadhesive, shows strong underwater adhesion upon hydration, adjustable biodegradation, and adequate physical properties by adjusting the ratio of poly(acrylic acid) and poly(methacrylic acid). Through ex vivo and in vivo evaluations using defective organs and the implantation of electronic devices, the suitability of using CUBAPs for effective wound healing in diverse internal organs is demonstrated. Thus, this innovative CUBAP system offers strong underwater adhesiveness with tailored biodegradation timing and physical properties, giving it great potential in various biomedical applications.

Efficient secretion of mussel adhesion proteins using a chaperone protein Spy as fusion tag in Bacillus subtilis

BACKGROUND

Mussel foot proteins (Mfps) are considered as remarkable materials due to their extraordinary adhesive capability. Recombinant expression is an ideal way to synthesis these proteins at large scale. However, secretory expression of Mfps into culture medium has not been achieved in a heterologous host.

METHODS AND RESULTS

Here, to realize the secretion of Mfp3 and Mfp5 in Bacillus subtilis, signal peptide screening was first performed. Minimal Mfp3-6×His was targeted into the growth medium with AmyE signal peptide. We found that a small chaperone protein Spy was secreted efficiently in B. subtilis, and the fusion proteins Spy-Mfp3-6×His and Spy-Mfp5-6×His could also be delivered into growth medium well. The yield of Spy-Mfp3-6×His and Spy-Mfp5-6×His reached 255 and 119 mg L-1 at shake flask conditions, respectively. Mfp3-6×His and Mfp5-6×His were finally purified via TEV protease cleavage and NTA affinity chromatography.

CONCLUSION

Mfp3-6×His and Mfp5-6×His could be efficiently secreted using a chaperone protein Spy as fusion tag in B. subtilis.

Protein-Based Biological Materials: Molecular Design and Artificial Production

Polymeric materials produced from fossil fuels have been intimately linked to the development of industrial activities in the 20th century and, consequently, to the transformation of our way of living. While this has brought many benefits, the fabrication and disposal of these materials is bringing enormous sustainable challenges. Thus, materials that are produced in a more sustainable fashion and whose degradation products are harmless to the environment are urgently needed. Natural biopolymers─which can compete with and sometimes surpass the performance of synthetic polymers─provide a great source of inspiration. They are made of natural chemicals, under benign environmental conditions, and their degradation products are harmless. Before these materials can be synthetically replicated, it is essential to elucidate their chemical design and biofabrication. For protein-based materials, this means obtaining the complete sequences of the proteinaceous building blocks, a task that historically took decades of research. Thus, we start this review with a historical perspective on early efforts to obtain the primary sequences of load-bearing proteins, followed by the latest developments in sequencing and proteomic technologies that have greatly accelerated sequencing of extracellular proteins. Next, four main classes of protein materials are presented, namely fibrous materials, bioelastomers exhibiting high reversible deformability, hard bulk materials, and biological adhesives. In each class, we focus on the design at the primary and secondary structure levels and discuss their interplays with the mechanical response. We finally discuss earlier and the latest research to artificially produce protein-based materials using biotechnology and synthetic biology, including current developments by start-up companies to scale-up the production of proteinaceous materials in an economically viable manner.

Building biomaterials through genetic code expansion

Genetic code expansion (GCE) enables directed incorporation of noncoded amino acids (NCAAs) and unnatural amino acids (UNAAs) into the active core that confers dedicated structure and function to engineered proteins. Many protein biomaterials are tandem repeats that intrinsically include NCAAs generated through post-translational modifications (PTMs) to execute assigned functions. Conventional genetic engineering approaches using prokaryotic systems have limited ability to biosynthesize functionally active biomaterials with NCAAs/UNAAs. Codon suppression and reassignment introduce NCAAs/UNAAs globally, allowing engineered proteins to be redesigned to mimic natural matrix-cell interactions for tissue engineering. Expanding the genetic code enables the engineering of biomaterials with catechols - growth factor mimetics that modulate cell-matrix interactions - thereby facilitating tissue-specific expression of genes and proteins. This method of protein engineering shows promise in achieving tissue-informed, tissue-compliant tunable biomaterials.

Mussel-Based Biomimetic Strategies in Musculoskeletal Disorder Treatment: From Synthesis Principles to Diverse Applications

Musculoskeletal disorders are the second leading cause of disability worldwide, posing a huge global burden to the public sanitation system. Currently, tissue engineering-based approaches act as effective strategies, which are, however, challenging in limited application scenarios. Mussel-based biomimetic materials, exhibit numerous unique properties such as intense adhesion, biocompatibility, moisture resistance, and injectability, to name only a few, and have attracted extensive research interest. In particular, featuring state-of-the-art properties, mussel-inspired biomaterials have been widely explored in innumerable musculoskeletal disorder treatments including osteochondral defects, osteosarcoma, osteoarthritis, ligament rupture, and osteoporosis. Nevertheless, a comprehensive and timely discussion of their applications in musculoskeletal disorders is insufficient. In this review, we emphasize on (1) the main categories and characteristics of mussel foot proteins and their fundamental mechanisms for the spectacular adhesion in mussels; (2) the diverse synthetic methods and modification of various polymers; and (3) the emerging applications of mussel-biomimetic materials, the future perspectives, and challenges, especially in the area of musculoskeletal disorder. We envision that this review will provide a unique and insightful perspective to improve the development of a new generation of mussel biomimetic strategies.

Engineering microbial cells with metal chelating hydroxylated unnatural amino acids for removable of synthetic pollutants from water

Lead (Pb²⁺) is a well-known heavy metal and toxic synthetic industrial pollutant in the ecosystem and causes severe threats to living organisms. It is paramount to develop a sustainable microbial engineering approach to remove synthetic pollutants from the environment. Genetic code engineering is emerging as an important microbial engineering tool in biosciences to biosynthesis congener protein production beyond the canonical set of natural molecules and expand the chemistries of living cells. Here, we prepare cells expressing unnatural amino acid encoded congener proteins for effectively removable toxic synthetic industrial pollutants (Pb²⁺) with high binding efficiency. Native and the developed congener proteins expressing cells adapted the Langmuir and Sips adsorption model that recommends uniform adsorption with Pb²⁺ ions. This could be due to a more significant number of functional groups on the protein surface. Fluorescence spectroscopic, field emission scanning electron microscope, X-ray photoelectron spectroscopic analysis, and protein-metal molecular stimulation coordination allowed us to explore the role of hydroxylation on Pb²⁺ adsorption. The bioreactor filled with immobilized protein-containing active granules showed >90% of lead removal in the contaminated water samples. The desorption of bound Pb2+ from GFP and its variants were studied by varying the pH to reuse the proteins for subsequent usage. We observed that about 70% of the GFP and its variants could be recycled and >75% of fluorescence efficiency could be recovered. Among all the variants, GFPHPDP exhibits high affinity and maintains the reusability efficiency in 7 consecutive cycles. These results suggest that genetic code engineering of cells encoding unnatural amino acids could be a next-generation microbial engineering tool for manipulating and developing the microbial strain's selective and effective removal of synthetic pollutants from the environment.

Expanding the chemical repertoire of protein-based polymers for drug-delivery applications

Expanding the chemical repertoire of natural and artificial protein-based polymers (PBPs) can enable the production of sequence-defined, yet chemically diverse, biopolymers with customized or new properties that cannot be accessed in PBPs composed of only natural amino acids. Various approaches can enable the expansion of the chemical repertoire of PBPs, including chemical and enzymatic treatments or the incorporation of unnatural amino acids. These techniques are employed to install a wide variety of chemical groups-such as bio-orthogonally reactive, cross-linkable, post-translation modifications, and environmentally responsive groups-which, in turn, can facilitate the design of customized PBP-based drug-delivery systems with modified, fine-tuned, or entirely new properties and functions. Here, we detail the existing and emerging technologies for expanding the chemical repertoire of PBPs and review several chemical groups that either demonstrate or are anticipated to show potential in the design of PBP-based drug delivery systems. Finally, we provide our perspective on the remaining challenges and future directions in this field.

Rational design of adhesives for effective underwater bonding

Underwater adhesives hold great promises in our daily life, biomedical fields and industrial engineering. Appropriate underwater bonding can reduce the huge cost from removing the target substance from water, and greatly lift working efficiency. However, different from bonding in air, underwater bonding is quite challenging. The existence of interfacial water prevents the intimate contact between the adhesives and the submerged surfaces, and water environment makes it difficult to achieve high cohesiveness. Even so, in recent years, various underwater adhesives with macroscopic adhesion abilities were emerged. These smart adhesives can ingeniously remove the interfacial water, and enhance cohesion by utilizing their special physicochemical properties or functional groups. In this mini review, we first give a detail introduction of the difficulties in underwater bonding. Further, we overview the recent strategies that are used to construct underwater adhesives, with the emphasis on how to overcome the difficulties of interfacial water and achieve high cohesiveness underwater. In addition, future perspectives of underwater adhesives from the view of practical applications are also discussed. We believe the review will provide inspirations for the discovery of new strategies to overcome the obstacles in underwater bonding, and therefore may contribute to designing effective underwater adhesives.

Establishing the Interface Layer on the Pentaerythritol Tetranitrate Surface via In Situ Reaction

Pentaerythritol tetranitrate (PETN) was coated by tannic acid (TA), polydopamine (PDA), and melamine-formaldehyde (MF) resins via in situ reaction to prepare PETN@TA, PETN@PDA, and PETN@MF microcapsules for reducing sensitivity and enhancing thermal stability of PETN. The coating effects of TA, PDA, and MF shells on PETN surfaces are characterized by scanning electron microscopy and atomic force microscopy. The structures of PETN@TA, PETN@PDA, and PETN@MF microcapsules are characterized by X-ray photoelectron spectroscopy, X-ray diffraction, and Fourier-transform infrared spectra. The performances of PETN@TA, PETN@PDA, and PETN@MF microcapsules are characterized by differential scanning calorimetry, accelerating rate calorimetry, explosion point, vacuum deflation volume, and mechanical sensitivity. The study results show that TA, PDA, and MF shells can coat the PETN surface well. Compared with pure PETN, the explosion point has an increase while the vacuum deflation volume and mechanical sensitivity have a decrease for PETN@TA, PETN@PDA, and PETN@MF microcapsules, illustrating that the safeties of PETN@TA, PETN@PDA, and PETN@MF microcapsules are enhanced. In addition, the initial decomposition temperature (T₀) and peak decomposition temperature (T_p) of PETN@TA, PETN@PDA, and PETN@MF microcapsules have a slight increase, demonstrating that the thermal stabilities of PETN@TA, PETN@PDA, and PETN@MF microcapsules are better than that of pure PETN. The obtained method can provide some guidance for the desensitizing of other energetic materials with high sensitivities.

Smart Internal Bio-Glues

Although smart bio-glues have been well documented, the development of internal bio-glues for non-invasive or minimally invasive surgery is still met with profound challenges such as safety risk and the lack of deep tissue penetration stimuli for internal usage. Herein, a series of smart internal bio-glues are developed via the integration of o-nitrobenzene modified biopolymers with up-conversion nanoparticles (UCNPs). Upon irradiation by near-infrared (NIR) light, the prepared smart bio-glues can undergo a gelation process, which may further induce strong adhesion between tissues under both dry and wet conditions based on multi-interactions. Moreover, those NIR light-responsive bio-glues with deeper tissue penetration ability demonstrate good biocompatibility, excellent hemostatic performance, and the potent ability to accelerate wound healing for both external and internal wounds. This work provides new opportunities for minimally invasive surgery, especially in internal wound healing using smart and robust bio-glues.

Oligonucleotide Discrimination Enabled by Tannic Acid-Coordinated Film-Coated Solid-State Nanopores

Discrimination of nucleotides serves as the basis for DNA sequencing using solid-state nanopores. However, the translocation of DNA is usually too fast to be detected, not to mention nucleotide discrimination. Here, we utilized polyphenolic TA and Fe³⁺, an attractive metal-organic thin film, and achieved a fast and robust surface coating for silicon nitride nanopores. The hydrophilic coating layer can greatly reduce the low-frequency noise of an original unstable nanopore, and the nanopore size can be finely tuned in situ at the nanoscale by simply adjusting the relative ratio of Fe³⁺ and TA monomers. Moreover, the hydrogen bonding interaction formed between the hydroxyl groups provided by TA and the phosphate groups of DNAs significantly increases the residence time of a short double-strand (100 bp) DNA. More importantly, we take advantage of the different strengths of hydrogen bonding interactions between the hydroxyl groups provided by TA and the analytes to discriminate between two oligonucleotide samples (oligodeoxycytidine and oligodeoxyadenosine) with similar sizes and lengths, of which the current signal patterns are significantly different using the coated nanopore. The results shed light on expanding the biochemical functionality of surface coatings on solid-state nanopores for future biomedical applications.

Ascidian-inspired aciduric hydrogels with high stretchability and adhesiveness promote gastric hemostasis and wound healing

Adhesives for gastric hemorrhage are of great clinical significance. However, it remains a major challenge in clinics due to its poor stability under acidic environments and low adhesion to wet tissues. Herein, inspired by the high adhesiveness of the ascidian secretory protein, we designed a series of aciduric bionic hydrogel adhesives (PDTAs) based on poly(γ-glutamic acid) (γ-PGA) and tannic acid (TA). The formation of hydrogel adhesives was attributed to the abundant hydrogen bonds between amide groups of PGA-DA and polyphenol groups of TA. These hydrogel adhesives exhibited enhanced wet tissue adhesion (400%), higher stretchability (800% elongation), and aciduric stability (7 days) compared with commercial fibrin glue. Rodent wound models indicated that the hydrogel adhesives demonstrated significant healing promotion due to ameliorating collagen deposition and angiogenesis. These hydrogel adhesives show great potential in treating gastric hemorrhages and promoting wound healing.

Adhesive Materials Inspired by Barnacle Underwater Adhesion: Biological Principles and Biomimetic Designs

Wet adhesion technology has potential applications in various fields, especially in the biomedical field, yet it has not been completely mastered by humans. Many aquatic organisms (e.g., mussels, sandcastle worms, and barnacles) have evolved into wet adhesion specialists with excellent underwater adhesion abilities, and mimicking their adhesion principles to engineer artificial adhesive materials offers an important avenue to address the wet adhesion issue. The crustacean barnacle secretes a proteinaceous adhesive called barnacle cement, with which they firmly attach their bodies to almost any substrate underwater. Owing to the unique chemical composition, structural property, and adhesion mechanism, barnacle cement has attracted widespread research interest as a novel model for designing biomimetic adhesive materials, with significant progress being made. To further boost the development of barnacle cement–inspired adhesive materials (BCIAMs), it is necessary to systematically summarize their design strategies and research advances. However, no relevant reviews have been published yet. In this context, we presented a systematic review for the first time. First, we introduced the underwater adhesion principles of natural barnacle cement, which lay the basis for the design of BCIAMs. Subsequently, we classified the BCIAMs into three major categories according to the different design strategies and summarized their research advances in great detail. Finally, we discussed the research challenge and future trends of this field. We believe that this review can not only improve our understanding of the molecular mechanism of barnacle underwater adhesion but also accelerate the development of barnacle-inspired wet adhesion technology.

Reagentless electrochemical biosensors through incorporation of unnatural amino acids on the protein structure

Typical protein biosensors employ chemical or genetic labeling of the protein, thus introducing an extraneous molecule to the wild-type parent protein, often changing the overall structure and properties of the protein. While these labeling methods have proven successful in many cases, they also have a series of disadvantages associated with their preparation and function. An alternative route for labeling proteins is the incorporation of unnatural amino acid (UAA) analogues, capable of acting as a label, into the structure of a protein. Such an approach, while changing the local microenvironment, poses less of a burden on the overall structure of the protein. L-DOPA is an analog of phenylalanine and contains a catechol moiety that participates in a quasi-reversible, two-electron redox process, thus making it suitable as an electrochemical label/reporter. The periplasmic glucose/galactose binding protein (GBP) was chosen to demonstrate this detection principle. Upon glucose binding, GBP undergoes a significant conformational change that is manifested as a change in the electrochemistry of L-DOPA. The electroactive GBP was immobilized onto gold nanoparticle-modified, polymerized caffeic acid, screen-printed carbon electrodes (GBP-LDOPA/AuNP/PCA/SPCE) for the purpose of direct measurement of glucose levels and serves as a proof-of-concept of the use of electrochemically-active unnatural amino acids as the label. The resulting reagentless GBP biosensors exhibited a highly selective and sensitive binding affinity for glucose in the micromolar range, laying the foundation for a new biosensing methodology based on global incorporation of an electroactive amino acid into the protein's primary sequence for highly selective electrochemical detection of compounds of interest.

Comparative analysis of mussel foot protein 3B co-expressed with tyrosinases provides a potential adhesive biomaterial

Mussel foot proteins (Mfps), which help mussels attach to various surfaces, are considered to be promising biomaterials due to their outstanding adhesive properties. However, limited production and lack of post-translational modifications of tyrosine residues into 3,4-dihydroxyphenylalanine (Dopa) in bacterial expression systems have hampered their applications. In the present study, for the first time we established the expression of recombinant Mytilus galloprovincialis foot protein type 3 variant B (fp-3B) in Escherichia coli; and achieved its viable production (~51 mg/L). Additionally, the Dopa content and adhesive properties of fp-3B co-expressed using various types of tyrosinases were compared. Consequently, the co-expression of fp-3B construct together with tyrosinase from Verrucomicrobium spinosum (TyrVs) yielded up to 87 mg/L of modified fp-3B; hydroxylation of tyrosine residues accounted for 57.18% by acid-borate difference spectroscopy. The modified fp-3B also showed significant coating and adhesive ability, and its bulk-scale adhesive strength was 2.9-fold higher than that of unmodified fp-3B. Compared with other type 3 mussel foot proteins, the high-yield expression and extensive hydroxylation level of the recombinant protein indicate that fp-3B co-expressed with TyrVs (3B-Vs) has the potential to be widely used as bioglues.

Beetle and mussel-inspired chimeric protein for fabricating anti-icing coating

Ice accretion on surfaces can cause serious damages and economic losses in industries and civilian facilities. Antifreeze proteins (AFPs) as evolutionary adaptation products of organisms to cold climates, provide solutions for alleviating icing problems. In this work, a chimeric protein Mfp-AFP was rationally designed combining mussel-inspired adhesive domain with Tenebrio molitor-derived antifreeze protein domain. Expectedly, the multifunctional Mfp-AFP can lower the freezing point of water and inhibit ice recrystallization. The chimeric protein could also readily modify diverse solid surfaces due to the adhesive domain containing Dopa, and resist frosting and delay ice formation due to the beetle-derived antifreeze fragment. Moreover, Mfp-AFP coatings display excellent biocompatibility proved by cytocompatibility and hemolysis assays. Here, the designed multifunctional protein coatings provide an alternative strategy for fabricating anti-icing surfaces.

Bioengineered Protein-based Adhesives for Biomedical Applications

Protein-based adhesives with their robust adhesion performance and excellent biocompatibility have been extensively explored over years. In particular, the unique adhesion behaviours of mussel and sandcastle worm inspired the development of synthetic adhesives. However, the chemical synthesized adhesives often demonstrate weak underwater adhesion performance and poor biocompatibility/biodegradability, limiting their further biomedical applications. In sharp contrast, genetically engineering endows the protein-based adhesives the ability to maintain underwater adhesion property as well as biocompatibility/biodegradability. Herein, we outline recent advances in the design and development of protein-based adhesives by genetic engineering. We summarize the fabrication and adhesion performance of elastin-like polypeptide-based adhesives, followed by mussel foot protein (mfp) based adhesives and other sources protein-based adhesives, such as, spider silk spidroin and suckerin. In addition, the biomedical applications of these bioengineered protein-based adhesives are presented. Finally, we give a brief summary and perspective on the future development of bioengineered protein-based adhesives.

Chemo-Biological Upcycling of Poly(ethylene terephthalate) to Multifunctional Coating Materials

Chemo-biological upcycling of poly(ethylene terephthalate) (PET) developed in this study includes the following key steps: chemo-enzymatic PET depolymerization, biotransformation of terephthalic acid (TPA) into catechol, and its application as a coating agent. Monomeric units were first produced through PET glycolysis into bis(2-hydroxyethyl) terephthalate (BHET), mono(2-hydroxyethyl) terephthalate (MHET), and PET oligomers, and enzymatic hydrolysis of these glycolyzed products using Bacillus subtilis esterase (Bs2Est). Bs2Est efficiently hydrolyzed glycolyzed products into TPA as a key enzyme for chemo-enzymatic depolymerization. Furthermore, catechol solution produced from TPA via a whole-cell biotransformation (Escherichia coli) could be directly used for functional coating on various substrates after simple cell removal from the culture medium without further purification and water-evaporation. This work demonstrates a proof-of-concept of a PET upcycling strategy via a combination of chemo-biological conversion of PET waste into multifunctional coating materials.

Strong, Multifaceted Guanidinium-Based Adhesion of Bioorganic Nanoparticles to Wet Biological Tissue

Gluing dynamic, wet biological tissue is important in injury treatment yet difficult to achieve. Polymeric adhesives are inconvenient to handle due to rapid cross-linking and can raise biocompatibility concerns. Inorganic nanoparticles adhere weakly to wet surfaces. Herein, an aqueous suspension of guanidinium-functionalized chitin nanoparticles as a biomedical adhesive with biocompatible, hemostatic, and antibacterial properties is developed. It glues porcine skin up to 3000-fold more strongly (30 kPa) than inorganic nanoparticles at the same concentration and adheres at neutral pH, which is unachievable with mussel-inspired adhesives alone. The glue exhibits an instant adhesion (2 min) to fully wet surfaces, and the glued assembly endures one-week underwater immersion. The suspension is lowly viscous and stable, hence sprayable and convenient to store. A nanomechanic study reveals that guanidinium moieties are chaotropic, creating strong, multifaceted noncovalent bonds with proteins: salt bridges comprising ionic attraction and bidentate hydrogen bonding with acidic moieties, cation-π interactions with aromatic moieties, and hydrophobic interactions. The adhesion mechanism provides a blueprint for advanced tissue adhesives.

Directed Evolution of an Improved Aminoacyl-tRNA Synthetase for Incorporation of L-3,4-Dihydroxyphenylalanine (L-DOPA)

The catechol group of 3,4-dihydroxyphenylalanine (L-DOPA) derived from L-tyrosine oxidation is a key post-translational modification (PTM) in many protein biomaterials and has potential as a bioorthogonal handle for precision protein conjugation applications such as antibody-drug conjugates. Despite this potential, indiscriminate enzymatic modification of exposed tyrosine residues or complete replacement of tyrosine using auxotrophic hosts remains the preferred method of introducing the catechol moiety into proteins, which precludes many protein engineering applications. We have developed new orthogonal translation machinery to site-specifically incorporate L-DOPA into recombinant proteins and a new fluorescent biosensor to selectively monitor L-DOPA incorporation in vivo. We show simultaneous biosynthesis and incorporation of L-DOPA and apply this translation machinery to engineer a novel metalloprotein containing a DOPA-Fe chromophore.

Ultra-strong bio-glue from genetically engineered polypeptides

The development of biomedical glues is an important, yet challenging task as seemingly mutually exclusive properties need to be combined in one material, i.e. strong adhesion and adaption to remodeling processes in healing tissue. Here, we report a biocompatible and biodegradable protein-based adhesive with high adhesion strengths. The maximum strength reaches 16.5 ± 2.2 MPa on hard substrates, which is comparable to that of commercial cyanoacrylate superglue and higher than other protein-based adhesives by at least one order of magnitude. Moreover, the strong adhesion on soft tissues qualifies the adhesive as biomedical glue outperforming some commercial products. Robust mechanical properties are realized without covalent bond formation during the adhesion process. A complex consisting of cationic supercharged polypeptides and anionic aromatic surfactants with lysine to surfactant molar ratio of 1:0.9 is driven by multiple supramolecular interactions enabling such strong adhesion. We demonstrate the glue's robust performance in vitro and in vivo for cosmetic and hemostasis applications and accelerated wound healing by comparison to surgical wound closures.

Electrochemical immunosensor based on mussel inspired coating for simultaneous detection and elimination of Staphylococcus aureus in drinks

Staphylococcus aureus (S. aureus) is one of the most commonly isolated foodborne pathogens, and is considered as a major cause of foodborne illnesses worldwide. However, the development of smart and accurate analytical methods for the simultaneous detection and elimination of S. aureus in matrices of food or drinks remains challenging. In the present work, a mussel-inspired material, ε-poly-l-lysine-3,4-dihydroxy benzaldehyde (EPD), was designed and fabricated based on its Schiff base structure. Owing to the robust ability of the material to adhere onto wet electrode surfaces and the pH-responsive properties of EPD, the prepared immunosensor exhibited an excellent detection limit and linear range with on-demand antibacterial activity. In real milk samples, the average values obtained from the immunosensor were approximate to the standard results obtained from the plate count method, and the relative standard deviation was 3.16–6.54%, suggesting the good accuracy of the developed method. Moreover, it exhibited good selectivity, reproducibility, and stability, thus demonstrating the potential significant applications of the electrochemical immunosensor in drinks safety monitoring.

A smart electrochemical immunosensor for the detection and elimination of Staphylococcus aureus in food with on-demand antibacterial activity.

Full incorporation of the noncanonical amino acid hydroxylysine as a surrogate for lysine in green fluorescent protein

The canonical set of amino acids leads to an exceptionally wide range of protein functionality, nevertheless, this set still exhibits limitations. The incorporation of noncanonical amino acids into proteins can enlarge its functional scope. Although proofreading will counteract the charging of tRNAs with other amino acids than the canonical ones, the translation machinery may still accept noncanonical amino acids as surrogates and incorporate them at the canonically prescribed locations within the protein sequence. Here, we use a cell-free expression system to demonstrate the full replacement of l-lysine by l-hydroxylysine at all lysine sites of recombinantly produced GFP. In vivo, as a main component of collagen, post-translational l-hydroxylysine generation enables the formation of cross-links. Our work represents a first step towards in vitro production of (modified) collagens, more generally of proteins that can easily be crosslinked.

Influence of Fluorination on Single-Molecule Unfolding and Rupture Pathways of a Mechanostable Protein Adhesion Complex

We investigated the influence of fluorination on unfolding and unbinding reaction pathways of a mechanostable protein complex comprising the tandem dyad XModule-Dockerin bound to Cohesin. Using single-molecule atomic force spectroscopy, we mapped the energy landscapes governing the unfolding and unbinding reactions. We then used sense codon suppression to substitute trifluoroleucine in place of canonical leucine globally in XMod-Doc. Although TFL substitution thermally destabilized XMod-Doc, it had little effect on XMod-Doc:Coh binding affinity at equilibrium. When we mechanically dissociated global TFL-substituted XMod-Doc from Coh, we observed the emergence of a new unbinding pathway with a lower energy barrier. Counterintuitively, when fluorination was restricted to Doc, we observed mechano-stabilization of the non-fluorinated neighboring XMod domain. This suggests that intramolecular deformation is modulated by fluorination and highlights the differences between equilibrium thermostability and non-equilibrium mechanostability. Future work is poised to investigate fluorination as a means to modulate mechanical properties of synthetic proteins and hydrogels.

Enhanced production of Dopa-incorporated mussel adhesive protein using engineered translational machineries

Mussel adhesive proteins (MAPs) have great potential as bioglues, particularly in wet conditions. Although in vivo residue-specific incorporation of 3,4-dihydroxyphenylalanine (Dopa) in tyrosine-auxotrophic Escherichia coli cells allows for production of Dopa-incorporated bioengineered MAPs (dMAPs), the low production yield hinders the practical application of dMAPs. This low production yield of dMAPs is due to low translational activity of a noncanonical amino acid, Dopa, in E. coli cells. Herein, to enhance the production yield of dMAPs, we investigated the coexpression of Dopa-recognizing tyrosyl-tRNA synthetases (TyrRSs). To use the Dopa-specific Methanococcus jannaschii TyrRS (MjTyrRS-Dopa), we altered the anticodon of tyrosyl-tRNA amber suppressor into AUA (MjtRNA^Tyr _AUA ) to recognize a tyrosine codon (AUA). Co-overexpression of MjTyrRS-Dopa and MjtRNA^Tyr _AUA increased the production yield of Dopa-incorporated MAP foot protein type 3 (dfp-3) by 57%. Similarly, overexpression of E. coli TyrRS (EcTyrRS) led to a 72% higher production yield of dfp-3. Even with coexpression of Dopa-recognizing TyrRSs, dfp-3 has a high Dopa incorporation yield (over 90%) compared to ones prepared without TyrRS coexpression.

Recent Advances in the Quantification and Modulation of Hydrophobic Interactions for Interfacial Applications

Hydrophobic interaction is responsible for a variety of colloidal phenomena, which also plays a key role in achieving the desired characteristics and functionalities for a wide range of interfacial applications. In this feature article, our recent advances in the quantification and modulation of hydrophobic interactions at both solid/water and air/water interfaces in different material systems have been reviewed. On the basis of surface forces apparatus (SFA) measurements of hydrophobic polymers (e.g., polystyrene), a three-regime hydrophobic interaction model that could satisfactorily encompass the hydrophobic interaction with different ranges was proposed. In addition, the atomic force microscope (AFM) coupled with various techniques such as the colloidal probe, the electrochemical process, and force mapping were employed to quantify the hydrophobic interaction from different perspectives. For the hydrophobic interactions involving deformable bubbles, the bubble probe AFM combined with reflection interference contrast microscopy (RICM) was used to simultaneously measure the interaction force and spatiotemporal evolution of the thin film drainage process between air bubbles and hydrophobized mica surfaces in an aqueous medium. The studies on the interactions of air bubbles with self-assembled monolayers (SAMs) demonstrated that the range of hydrophobic interactions does not always increase monotonically with the hydrophobicity of interacting surfaces as characterized by the static water contact angle; viz., surfaces with similar hydrophobicity can exhibit different ranges of hydrophobic interaction, while surfaces with different hydrophobicities can exhibit a similar range of hydrophobic interactions. It is found that the hydrophobic interaction can be modulated by tuning the surface nanoscale structure and chemistry. Moreover, the long-range "hydrophilic" attraction that resembles the hydrophobic interaction was discovered between water droplets and polyelectrolyte surfaces in an oil medium, on the basis of which polyelectrolyte coating materials were designed for oil cleaning, oil/water separation, and demulsification. The interfacial applications, remaining challenges, and future perspectives of hydrophobic interactions are discussed.

Fabrication and Mechanical Properties of Engineered Protein-Based Adhesives and Fibers

Protein-based structural biomaterials are of great interest for various applications because the sequence flexibility within the proteins may result in their improved mechanical and structural integrity and tunability. As the two representative examples, protein-based adhesives and fibers have attracted tremendous attention. The typical protein adhesives, which are secreted by mussels, sandcastle worms, barnacles, and caddisfly larvae, exhibit robust underwater adhesion performance. In order to mimic the adhesion performance of these marine organisms, two main biological adhesives are presented, including genetically engineered protein-based adhesives and biomimetic chemically synthetized adhesives. Moreover, various protein-based fibers inspired by spider and silkworm proteins, collagen, elastin, and resilin are studied extensively. The achievements in synthesis and fabrication of structural biomaterials by DNA recombinant technology and chemical regeneration certainly will accelerate the explorations and applications of protein-based adhesives and fibers in wound healing, tissue regeneration, drug delivery, biosensors, and other high-tech applications. However, the mechanical properties of the biological structural materials still do not match those of natural systems. More efforts need to be devoted to the study of the interplay of the protein structure, cohesion and adhesion effects, fiber processing, and mechanical performance.

Recent progress in synthesis and application of mussel-inspired adhesives

The rapid and robust adhesion of marine mussels to diverse solid surfaces in wet environments is mediated by the secreted mussel adhesive proteins which are abundant in a catecholic amino acid, l-3,4-dihydroxyphenylalanine (Dopa). Over the last two decades, enormous efforts have been devoted to the development of synthetic mussel-inspired adhesives with water-resistant adhesion and cohesion properties by modifying polymer systems with Dopa and its analogues. In the present review, an overview of the unique features of various mussel foot proteins is provided in combination with an up-to-date understanding of catechol chemistry, which contributes to the strong interfacial binding via balancing a variety of covalent and noncovalent interactions including oxidative cross-linking, electrostatic interaction, metal-catechol coordination, hydrogen bonding, hydrophobic interactions and π-π/cation-π interactions. The recent developments of novel Dopa-containing adhesives with on-demand mechanical properties and other functionalities are then summarized under four broad categories: viscous coacervated adhesives, soft adhesive hydrogels, smart adhesives, and stiff adhesive polyesters, where their emerging applications in engineering, biological and biomedical fields are discussed. Limitations of the developed adhesives are identified and future research perspectives in this field are proposed.

Mussel-inspired hydrogels: from design principles to promising applications

This review presents the recent progress of mussel-inspired hydrogels from fundamental interaction mechanisms and design principles to promising applications.

Adhesive Properties of Adsorbed Layers of Two Recombinant Mussel Foot Proteins with Different Levels of DOPA and Tyrosine

Using a surface forces apparatus and an atomic force microscope, we characterized the adhesive properties of adsorbed layers of two recombinant variants of Perna viridis foot protein 5 (PVFP-5), the main surface-binding protein in the adhesive plaque of the Asian green mussel. In one variant, all tyrosine residues were modified into 3,4-dihydroxy-l-phenylalanine (DOPA) during expression using a residue-specific incorporation strategy. DOPA is a key molecular moiety underlying underwater mussel adhesion. In the other variant, all tyrosine residues were preserved. The layer was adsorbed on a mica substrate and pressed against an uncoated surface. While DOPA produced a stronger adhesion than tyrosine in contact with the nanoscopic Si₃N₄ probe of the atomic force microscope, the two variants produced comparable adhesion on the curved macroscopic mica surfaces of the surface forces apparatus. These findings show that the presence of DOPA is not a sufficient condition to generate strong underwater adhesion. Surface chemistry and contact geometry affect the strength and abundance of protein-surface bonds created during adsorption and surface contact. Importantly, the adsorbed protein layer has a random and dynamic polymer-network structure that should be optimized to transmit the tensile stress generated during surface separation to DOPA surface bonds rather than other weaker bonds.

Metal-crosslinked ɛ-poly-L-lysine tissue adhesives with high adhesive performance: Inspiration from mussel adhesive environment

Strong glue of mussels has long been considered as an ideal model to design synthetic bio-adhesives but the adhesive strength of metal-crosslinked mussel-inspired glues is not often satisfactory. Herein, inspired by the adhesive environment of mussels, we obtained metal-crosslinked ε-poly-L-lysine adhesives with high adhesive performance by introducing the elements of suitable adhesive environment (SAE) into the adhesives. The elements of SAE were clarified as weak alkaline conditions (pH ∼ 7.4) and low Fe³⁺ contents. The adhesive strength (∼105 kPa) of the metal-crosslinked adhesives endowed with the elements of SAE (PL-Cat/Fe-SAE) was about 8 times higher than that of fibrin glues. The high adhesive strength was found to originate from distinctive interfacial adhesion and cohesion strength of PL-Cat/Fe-SAE. PL-Cat/Fe-SAE showed strong interfacial adhesion capacity and nearly comparable cohesion strength to those PL-Cat/Fe adhesives with higher Fe³⁺ contents. The nearly comparable cohesion strength of PL-Cat/Fe-SAE was then found to be due to more amount of stable tris-complex existed in PL-Cat/Fe-SAE. In addition, PL-Cat/Fe-SAE was able to efficiently close the full thickness skin incisions. The study highlighted the importance of introducing SAE elements into the design of tissue adhesives and provided a facile and efficient strategy for constructing tissue adhesives with high adhesive performance.

Stabilization of the triple helix in collagen mimicking peptides

Collagen mimics are peptides designed to reproduce structural features of natural collagen. A triple helix is the first element in the hierarchy of collagen folding. It is an assembly of three parallel peptide chains stabilized by packing and interchain hydrogen bonds. In this review we summarize the existing chemical approaches towards stabilization of this structure including the most recent developments. Currently proposed methods include manipulation of the amino acid composition, application of unnatural amino acid analogues, stimuli-responsive modifications, chain tethering approaches, peptide amphiphiles, modifications that target interchain interactions and more. This ability to manipulate the triple helix as a supramolecular self-assembly contributes to our understanding of the collagen folding. It also provides essential information needed to design collagen-based biomaterials of the future.

Bioinspired Multifunctional Protein Coating for Antifogging, Self-Cleaning, and Antimicrobial Properties

A multifunctional coating with antifogging, self-cleaning, and antimicrobial properties has been prepared based on a mussel-inspired chimeric protein MP-KE, which is the first example that these proteins were successfully applied to fabricate antifogging surfaces. The coating exhibits super hydrophilic properties, as indicated by contact angles less than 5° and high light transmittance similar to bare glass substrates about 90%. The zwitterionic peptides of MP-KE empower water molecules to expand into thin hydrated films rapidly, providing the protein coating with diverse surface functions. Moreover, the coatings have excellent stability and a convenient preparation process because of the mussel adhesive motif of MP-KE which makes the coating anchor onto the surface strongly. As a protein material, this multifunctional coating possesses remarkable biocompatibility and has a potential application prospects in the biomedical and pharmaceutical fields.

Multi-dimensional bioinspired tactics using an engineered mussel protein glue-based nanofiber conduit for accelerated functional nerve regeneration

Limited regenerative capacity of the nervous system makes treating traumatic nerve injuries with conventional polymer-based nerve grafting a challenging task. Consequently, utilizing natural polymers and biomimetic topologies became obvious strategies for nerve conduit designs. As a bioinspired natural polymer from a marine organism, mussel adhesive proteins (MAPs) fused with biofunctional peptides from extracellular matrix (ECM) were engineered for accelerated nerve regeneration by enhancing cell adhesion, proliferation, neural differentiation, and neurite formation. To physically promote contact guidance of neural and Schwann cells and to achieve guided nerve regeneration, MAP was fabricated into an electrospun aligned nanofiber conduit by introducing synthetic polymer poly(lactic-co-glycolic acid) (PLGA) to control solubility and mechanical property. In vitro and in vivo experiments demonstrated that the multi-dimensional tactics of combining adhesiveness from MAP, integrin-mediated interaction from ECM peptides (in particular, IKVAV derived from laminin α1 chain), and contact guidance from aligned nanofibers synergistically accelerated functional nerve regeneration. Thus, MAP-based multi-dimensional approach provides new opportunities for neural regenerative applications including nerve grafting. STATEMENT OF SIGNIFICANCE: Findings in neural regeneration indicate that a bioinspired polymer-based nerve conduit design should harmoniously constitute various factors, such as biocompatibility, neurotrophic molecule, biodegradability, and contact guidance. Here, we engineered three fusion proteins of mussel-derived adhesive protein with ECM-derived biofunctional peptides to simultaneously provide biocompatibility and integrin-based interactions. In addition, a fabrication of robust aligned nanofiber conduits containing the fusion proteins realized suitable biodegradability and contact guidance. Thus, our multi-dimensional strategy on conduit design provided outstanding biocompatibility, biodegradability, integrin-interaction, and contact guidance to achieve an accelerated functional nerve regeneration. We believe that our bioengineered mussel adhesive protein-based multi-dimensional strategy would offer new insights into the design of nerve tissue engineering biomaterials.

Coacervation of Interfacial Adhesive Proteins for Initial Mussel Adhesion to a Wet Surface

Coacervation of mussel adhesive proteins (MAPs) is proposed as a potential strategy that mussels may use during secretion due to their high concentration density, lack of dispersion into seawater, and low interfacial tension. Particularly, coacervations of interfacial MAPs, foot protein type-3 fast variant (fp-3F) and type-5 (fp-5), are important in the initial mussel adhesion process due to the relationship between the easy secretion/surface wetting properties of the coacervate and primer-like surface adhesive role of interfacial MAPs, which directly contact the marine surface. To the best of the authors' knowledge, this is the first report on coacervate formation of major recombinant interfacial MAPs with high charge densities and the highest 3,4-dihydroxyphenylalanine (Dopa) contents. Specifically, salt-induced coacervation of fp-3F is observed at low pH values corresponding to the acidified environment of the distal depression during mussel secretion. In addition, it shows enthalpy driven upper critical solution temperature behavior, possibly relying on bridging interactions between like-charged cationic fp-3Fs including salt-bridge and cation-π/π-π interactions in the presence of specific counterions, supported by Raman spectroscopy. It is believed that this study has broadened the scope of the understanding of coacervation of MAPs and may provide new insight for responsive biomaterial design.

Mussel-inspired in situ forming adhesive hydrogels with anti-microbial and hemostatic capacities for wound healing

All kinds of commercially available wound dressings are clinically used as fleshly obstacles and therapeutic materials in opposition to microbial incursion. Few researches focused on effective-bleeding and anti-bacteria at the same time. In order to better solve this problem, two hydrogels were synthetized in this study. One is phosphate buffer solution-activated dopamine-modified-γ-poly glutamic acid (PBS-PD) hydrogel, the other one is cirsium setosum extracts-activated dopamine-modified-γ-poly glutamic acid (CSE-PD) hydrogel. The two hydrogels are prepared by applying an enzyme-catalyzed crosslinking means in the presence of horseradish peroxidase (HRP) and hydrogen peroxide (H2O2). The chemical structures were characterized through 1H-NMR and FT-IR. In conclusion, both PBS-PD and CSE-PD hydrogels exhibit superior tissue adhesion properties, and remarkable anti-infection quality. In addition, these two hydrogels manifest prominent hemostatic efficiency. The bio adhesion performance can achieve 30 kPa, meanwhile the CSE-PD hydrogels show good germicidal properties, and the antibacterial rate can reach 98%. The hydrogels could reduce blood loss without any obvious side effect, and present a new prospect in the field of hemostasis rapidly.