Resist Protein Adsorption Research Articles

Glycopolymeric Nanoparticles Enrich Less Immunogenic Protein Coronas, Reduce Mononuclear Phagocyte Clearance, and Improve Tumor Delivery Compared to PEGylated Nanoparticles.

Nanoparticles (NPs) offer significant promise as drug delivery vehicles; however, their in vivo efficacy is often hindered by the formation of a protein corona (PC), which influences key physiological responses such as blood circulation time, biodistribution, cellular uptake, and intracellular localization. Understanding NP-PC interactions is crucial for optimizing NP design for biomedical applications. Traditional approaches have utilized hydrophilic polymer coatings like polyethylene glycol (PEG) to resist protein adsorption, but glycopolymer-coated nanoparticles have emerged as potential alternatives due to their biocompatibility and ability to reduce the adsorption of highly immunogenic proteins. In this study, we synthesized and characterized glycopolymer-based poly[2-(diisopropylamino)ethyl methacrylate-b-poly(methacrylamidoglucopyranose) (PDPA-b-PMAG) NPs as an alternative to PEGylated NPs. We characterized the polymers using a range of techniques to establish their molecular weight and chemical composition. PMAG and PEG-based NPs showed equivalent physicochemical properties with sizes of ∼100 nm, spherical morphology, and neutral surface charges. We next assessed the magnitude of protein adsorption on both NPs and catalogued the identity of the adsorbed proteins using mass spectrometry-based techniques. The PMAG NPs were found to adsorb fewer proteins in vitro as well as fewer immunogenic proteins such as Immunoglobulins and Complement proteins. Flow cytometry and confocal microscopy were employed to examine cellular uptake in RAW 264.7 macrophages and MDA-MB-231 tumor cells, where PMAG NPs showed higher uptake into tumor cells over macrophages. In vivo studies in BALB/c mice with orthotopic 4T1 breast cancer xenografts showed that PMAG NPs exhibited prolonged circulation times and enhanced tumor accumulation compared to PEGylated NPs. The biodistribution analysis also revealed greater selectivity for tumor tissue over the liver for PMAG NPs. These findings highlight the potential of glycopolymeric NPs to improve tumor targeting and reduce macrophage uptake compared to PEGylated NPs, offering significant advancements in cancer nanomedicine and immunotherapy.

Effect of protein adsorption on hyaluronic acid/curcumin/multi-walled carbon nanotube based electrochemical sensor for detection of dopamine

Resisting protein adsorption on electrode surfaces is one of pivotal challenges in the electrochemical analysis of small bioactive molecules. In this work, we constructed a novel electrochemical sensing electrode modified with hydrophilic hyaluronic acid (HA) and curcumin/multi-walled carbon nanotube (CM/MWCNTs). The modified electrodes were comprehensively characterized for dopamine detection including the sensing sensitivity, selectivity and stability. The constructed electrochemical sensor for dopamine detection exhibited remarkable resistance to protein adsorption because of the inherent hydrophilicity of HA, and synergistically, the superior electrochemical behavior of the CM/MWCNTs composite (quinone/hydroquinone redox couples enabled superior electrochemical behavior). The HA/CM/MWCNTs/GCE performed about 5.0 folds, 3.5 folds and 2.4 folds higher electrocatalytic current for dopamine than that revealed at bare GCE, MWCNTs/GCE, and CM/MWCNTs/GCE, respectively. In addition, the HA/CM/MWCNTs-based sensor demonstrated excellent sensing performance with a low detection limit of 0.009 μM (S/N = 3) within the concentration range from 50 to 200 μM. The constructed HA/CM/MWCNTs-modified glassy carbon electrodes offered a reliable platform for the real-time monitoring of dopamine with no protein absorption.

An antifouling membrane-fusogenic liposome for effective intracellular delivery in vivo

The membrane-fusion-based internalization without lysosomal entrapment is advantageous for intracellular delivery over endocytosis. However, protein corona formed on the membrane-fusogenic liposome surface converts its membrane-fusion performance to lysosome-dependent endocytosis, causing poorer delivery efficiency in biological conditions. Herein, we develop an antifouling membrane-fusogenic liposome for effective intracellular delivery in vivo. Leveraging specific lipid composition at an optimized ratio, such antifouling membrane-fusogenic liposome facilitates fusion capacity even in protein-rich conditions, attributed to the copious zwitterionic phosphorylcholine groups for protein-adsorption resistance. Consequently, the antifouling membrane-fusogenic liposome demonstrates robust membrane-fusion-mediated delivery in the medium with up to 38% fetal bovine serum, outclassing two traditional membrane-fusogenic liposomes effective at 4% and 6% concentrations. When injected into mice, antifouling membrane-fusogenic liposomes can keep their membrane-fusion-transportation behaviors, thereby achieving efficient luciferase transfection and enhancing gene-editing-mediated viral inhibition. This study provides a promising tool for effective intracellular delivery under complex physiological environments, enlightening future nanomedicine design.

Antifouling and antimicrobial 3D printed small household appliances with incorporation of zwitterions and quaternary ammonium compounds

Nowadays, small household appliances had revolutionized the way we live and work with unparalleled innovation and performance, but the bacterial colonization of the appliance surfaces was a widespread phenomenon with consequences on human health and well-being. In this work, a spectrum of composite resins with addition of different ratios of sulfobetaine methacrylate (SBMA) and 12-methacryloyloxydodecylpyridinium bromide (MDPB) were prepared by photocuring 3D printing technology for improving their antifouling and antimicrobial properties. A remarkable improvement in mechanical property was observed as a result of the electrostatic attraction between SBMA, MDPB and polyurethane. The composite resins exhibited a relatively hydrophilic surface because of the high hydration capacity of zwitterionic SBMA, which enabled effective suppression of protein adsorption and bacterial adhesion, resulting in excellent antifouling property. Meanwhile, the antimicrobial property of the composite resins against both S. aureus (Gram-positive bacteria) and E. coli (Gram-negative bacteria) was significantly improved in the presence of MDPB, and the resins with 20% MDPB showed the best antimicrobial property, with a reduction rate of 98.3% and 97.1% against S. aureus and E. coli, respectively. Not only that, all composite resins persevered low cytotoxicity and good biocompatibility. More importantly, a series of children's nebulizers with enhanced protein adsorption resistance, reduced bacterial fouling and sustained biocompatibility were fabricated by photocuring 3D printing technology using the composite resins, confirming the success of antifouling and antimicrobial composite resin strategy in small household appliances.

Microfluidic nanoprecipitation of PEGylated PLGA nanoparticles with rapamycin and performance evaluation

Rapamycin (RAP) is currently being developed as potential antibreast cancer drug. However, its poor solubility completely limits its use. The aim of this study was to develop polyethylene glycol-poly(lactide-co-glycolide) (PEG-PLGA)-based nanoparticles (NPs) to load RAP via microfluidics with an appropriate polyethylene glycol (PEG) content to enhance the bioavailability of RAP. Polydimethylsiloxane (PDMS) chips with a Y-shaped channel were designed to obtain RAP-loaded PEG-PLGA NPs (RAP-PEG-PLGA). The entrapment efficiency (EE) and drug loading (DL) as well as release profile of RAP-PEG-PLGA were evaluated, and their resistance to plasma albumin adsorption of NPs with different PEG contents was evaluated and compared. RAW264.7 and 4T1 cells were used to assess the antiphagocytic and anticancer cells effect of NPs, respectively. RAP-PEG-PLGA of around 124 nm in size were successfully prepared with the EE of 82.0% and DL of 12.3%, and sustained release for around 40 d. A PEG relative content of 10% within the PEG-PLGA molecule was shown superior in resisting protein adsorption. RAP-PEG-PLGA inhibited the growth of breast cancer cells when the concentration was over 10 μg/mL, and the inhibition efficiency was significantly higher than free RAP. Hence, the current RAP-PEG-PLGA could be a potential therapeutic system for breast cancer treatment.

One-step prepared of e-Gelatin-CNTs nano-composite fiber modified carbon fiber microelectrode for continuous dopamine monitoring: Characterization, biocompatibility evaluation and in vivo experiment

Fabricating electrochemical sensor capable of stable sensing in complex organism's environment will undoubtedly underpin key in the development of implanted electrochemical sensor. However, nonspecific protein adsorption can greatly reduce sensing sensitivity of electrode due to the abundance of protein in vivo. Herein, we aim to fabricating a modified layer of good protein adsorption resistance. The nano-composite fibers from gelatin with good hydrophily and multiwall carbon nanotubes (CNTs) for constructing on the surface of carbon fiber microelectrode using one-step electrospinning technology (e-Gelatin-CNTs/CFME). A comprehensive discussing on the protein adsorption resistance of e-Gelatin-CNTs/CFME that are, through the use of SEM, AFM, water contact angle, UV–vis, cyclic voltammetry and I-T. The resulting electrochemical sensor revealed stable sensing sensitivity in protein solution, a slightly decrease (0.02nA/μM). Furthermore, the sensor was successfully used for the detection of DA in human blood. More remarkable, e-Gelatin-CNTs nano-composite fibers presented excellent biocompatibility, which could meet the biosafety as implantation materials in vivo. This work provided a platform for the development of implantable electrochemical sensor.

Current paradigms in employing self-assembled structures: Drug delivery implications with improved therapeutic potential

Recent efforts have focused on developing improved drug delivery systems with enhanced therapeutic efficacy and minimal side effects. Micelles, self-assembled from amphiphilic block copolymers in aqueous solutions, have gained considerable attention for drug delivery. However, there is a need to further enhance their efficiency. These micelles offer benefits like biodegradability, biocompatibility, sustained drug release, and improved patient compliance. Yet, researchers must address stability issues and reduce toxicity. Nanoscale self-assembled structures have shown promise as efficient drug carriers, offering an alternative to conventional methods. Fine-tuning at the monomeric and molecular levels, along with structural modifications, is crucial for optimal drug release profiles. Various strategies, such as entrapping hydrophobic drugs and using polyethylene oxide diblock copolymer micelles to resist protein adsorption and cellular adhesion, protect the hydrophobic core from degradation. The polyethylene oxide corona also provides stealth properties, prolonging blood circulation for extended drug administration. Amphiphilic copolymers are attractive for drug delivery due to their adjustable properties, allowing control over micelle size and morphology. Emerging tools promise complex and multifunctional platforms. This article summarizes about the challenges as far as the use of micelles is concerned, including optimizing performance, rigorous pre-clinical and clinical research, and suggests further improvement for drug delivery efficacy.

Hydrophobic fouling-resistant electrospun nanofiber membranes from poly(vinylidene fluoride)/polyampholyte blends.

This study reports the fabrication of non-woven fibrous membranes from electrospinning blended solutions of PVDF with polyampholytes in N,N-dimethylformamide and methanol. Polyampholytes are macromolecules that have both positive and negative charged units in different side groups attached to the backbone. In this study, we used a random polyampholyte amphiphilic copolymer (r-PAC) synthesized by co-polymerizing a hydrophobic monomer in addition to the positive and negative charged monomer units, to reduce the fouling propensity of PVDF electrospun membranes while preserving its inherent hydrophobicity. Blends of PVDF/r-PAC were electrospun across the full range of compositions from 0/100 to 100/0. Scanning electron microscopic analysis showed formation of beaded fibers with average fibril diameters from 0.09-0.18 μm. The variation in the fiber diameters is caused by the change in surface charge density, dynamic viscosity of the solution, and the instability of the Taylor cone. Bead formation was observed in the mats electrospun from less viscous solutions. Wide angle X-ray scattering showed that electrospun fibers of PVDF crystallized into the electro-active β and γ crystal phases, whereas polyampholytes were amorphous. Thermogravimetry showed that the PVDF/r-PAC blends have a multi-step thermal degradation mechanism while PVDF homopolymer showed single-step thermal degradation. Sessile drop contact angle measurements confirmed that fibers possess high hydrophobicity and super-oleophilicity. Adsorptive fouling experiments with a fluorescently labeled protein confirmed that the fiber mats obtained from the PVDF/r-PAC blends resist protein adsorption, exhibiting highly enhanced fouling resistance compared to the fibers obtained from homopolymer PVDF.

Achieving superior anticoagulation of endothelial membrane mimetic coating by heparin grafting at zwitterionic biocompatible interfaces

Thrombosis and bleeding are common complications of blood-contacting medical device therapies. In this work, an endothelium membrane mimetic coating (PMPCC/Hep) has been created to address these challenges. The coating is fabricated by multi-point anchoring of a phosphorylcholine copolymer (poly-MPC-co-MSA, PMPCC) with carboxylic side chains and end-group grafting of unfractionated heparin (Hep) onto polydopamine precoated blood-contacting material surfaces. The PMPCC coating forms an ultrathin cell outer membrane mimetic layer to resist protein adsorption and platelet adhesion. The tiny defects/pores of the PMPCC layer provide entrances for heparin end-group to be inserted and grafted onto the sub-layer amino groups. The combination of the PMPCC cell membrane mimetic anti-fouling nature with the grafted heparin bioactivity further enhances the anticoagulation performance of the formed endothelium membrane mimetic PMPCC/Hep coating. Compared to conventional Hep coating, the PMPCC/Hep coating further decreases protein adsorption and platelet adhesion by 50 % and 90 %, respectively. More significantly, the PMPCC/Hep coating shows a superior anticoagulation activity, even significantly higher than that of an end-point-attached heparin coating. Furthermore, the blood coagulation function is well preserved in the PMPCC/Hep coating anticoagulation strategy. All the results support that the PMPCC/Hep coating strategy has great potential in developing more efficient and safer blood-contacting medical devices.

Cocontinuous Nanostructures by Microphase Separation of Statistically Cross-Linked Polystyrene/Poly(2-vinylpyridine) Networks.

Cocontinuous polymeric nanostructures have drawn considerable attention due to their ability to combine distinct, percolation-dependent properties of two different polymer domains. Randomly end-linked copolymer networks (RECNs) have previously been shown to support the formation of disordered cocontinuous nanostructures across wide composition windows in a robust way. However, achieving highly efficient linking of telechelic polymers with excellent end-group fidelity often requires complex synthetic routes. As an alternative, we study here statistically cross-linked copolymer networks (SCCNs) composed of polystyrene and poly(2-vinylpyridine) (PS and P2VP) with cross-linkable allyl pendent groups that are conveniently synthesized by controlled radical copolymerization. Via selective extraction of P2VP, coupled with gravimetry, small-angle X-ray scattering, and electron microscopy, we find disordered cocontinuous phases across wide composition ranges (up to ≈ 35 wt %), approaching values previously determined for RECNs. Remarkably, even for samples that appear to exhibit full percolation, a substantial fraction of P2VP (≈ 20-30 wt %) cannot be removed, which we ascribe to short strands between nearby cross-linkers that are physically embedded within PS domains. The resulting PS porous monoliths with residual surface P2VP layers enable facile surface modification to resist protein adsorption and templating of porous gold nanostructures.

Discrete polyethylene glycol derivatives as a potent impetus for next-generation biomedicines

PEGylation, which covalently modifies small-molecule drugs, peptides and proteins with polyethylene glycol (PEG) to improve their pharmacokinetics and efficacy, has become one of the most widely used drug modification techniques. However, PEG and its derivatives have been verified to be immunogenic and antigenic, which directly lead to side effects such as accelerated blood clearance (ABC) phenomenon and allergic reactions to PEGylated drugs or PEG excipients. Recent development of single molecular weight discrete PEG synthesis methodology have led to continuous and extensive focus on the difference in biological activity between conventional polydisperse PEG and single molecular weight precise PEG. Discrete PEG has demonstrated obvious advantages in resisting protein adsorption, cell adhesion and enhancing drug efficacy. These preliminary results not only confirm the significant impact of PEG chain polydispersity on its biological effect, but also reveal the possibility and potential advantages of using discrete PEG to reduce the immunogenicity and antigenicity. Hopefully, single chemical structure and molecular weight ensure the batch repeatability of newly developed discrete PEG products, and facilitate the understanding of their physicochemical properties and biological effects that promoting the clinical conversion of precise PEG drugs.

Unexpectedly resisting protein adsorption on self-assembled monolayers terminated with two hydrophilic hydroxyl groups.

OH-terminated self-assembled monolayers, as protein-resistant surfaces, have significant potential in biocompatible implant devices, which can avoid or reduce adverse reactions caused by protein adhesion to biomaterial surfaces, such as thrombosis, immune response and inflammation. Here, molecular dynamics simulations were performed to evaluate the degree of protein adsorption on the self-assembled monolayer terminated with two hydrophilic OH groups ((OH)2-SAM) at packing densities (Σ) of 4.5 nm-2 and 6.5 nm-2, respectively. The results show that the structure of the (OH)2-SAM itself, i.e., a nearly perfect hexagonal-ice-like hydrogen bond structure in the OH matrix of the (OH)2-SAM at Σ = 4.5 nm-2 sharply reduces the number of hydrogen bonds (i.e., 0.7 ± 0.27) formed between the hydrophobic (OH)2-SAM surface and protein. While for Σ = 6.5 nm-2, the hydrophilic (OH)2-SAM surface can provide more hydrogen bonding sites to form hydrogen bonds (i.e., 6.2 ± 1.07) with protein. The number of hydrogen bonds formed between the (OH)2-SAM and protein at Σ = 6.5 nm-2 is ∼8 times higher than that at Σ = 4.5 nm-2, reflecting the excellent resistance to protein adsorption exhibited by the structure of the (OH)2-SAM itself at Σ = 4.5 nm-2. Compared with a traditional physical barrier effect formed by a large number of hydrogen bonds between the (OH)2-SAM and water at Σ = 6.5 nm-2, the structure of the (OH)2-SAM itself at Σ = 4.5 nm-2 proposed in this study significantly improves the performance of the (OH)2-SAM resistance to protein adsorption, which provides new insights into the mechanism of resistance to protein adsorption on the (OH)2-SAM.

High durability of food due to the flow cytometry proved antibacterial and antifouling properties of TiO2 decorated nanocomposite films.

Although polymeric membrane has superior properties, its applications in biomedical and food industrial fields are minimal. Biofouling is a significant concern in the membrane, created from particular interactions between the membrane and untreated water content. This research showed that a careful superhydrophilic modification of polyethersulfone membrane could address those drawbacks that have hindered their utility. Hence, a combination of chemical and physical modification showed far-reaching effects on surface behavior, affecting manifold aspects of its bacterial attachment, protein adsorption resistance, and hydrophilicity. The contact angle measurement results decreased from 30° to 0° in 26s, and surface free energy increased by 33%, demonstrating the shifting surface wettability behavior toward the Superhydrophilicity. Besides, increasing the average surface roughness on the nanoscale and forming 70-110nm jagged structures results in a marked reduction in protein adsorption, bacterial adhesion, and biofouling formation, confirmed by the results of Flow cytometry analysis and microtiter plate assay. An improved understanding of antifouling and antibacterial properties will greatly assist in food industries since it can be applied to enhance the durability of food and chemical materials. This is important as it gives us a simple way of improving packing reliability, reducing costs and amounts of undesirable waste products.

Synthesis of water-compatible noncovalent imprinted microspheres for acidic or basic biomolecules designed based on molecular dynamics

Molecularly imprinted polymers (MIPs), as selective adsorbents, have shown great potential in the selective separation and enrichment of trace targets from complex components. However, the preparation of MIPs with specific recognition in aqueous solution is facing great challenges, thus largely limiting their application scope in selective separation and analysis of water samples. Aiming at the challenges and problems in the above-mentioned molecularly imprinting technology, a new rational method of water-compatible noncovalent imprinted microspheres was proposed. In the method, functional monomers were screened based on molecular dynamics (MD) and then water-compatible spherical MIPs were prepared with a modified suspension polymerization method. To verify this method, a basic molecule (spiramycin) and an acidic molecule (chenodeoxycholic acid) were selected as templates. After the characterization of the synthesized polymers, the adsorption capacities of SPM-MIP and CDCA-MIP were tested in an aqueous environment. In adsorption experiments, CDCA-MIP and SPM-MIP showed higher adsorption capacities and the imprinting factors of CDCA-MIP and SPM-MIP reached 3.96 and 2.51, respectively. Due to the imprinting effect, the prepared SPM-MIP and CDCA-MIP had selectivity. Moreover, SPM-MIP and CDCA-MIP showed the strong protein adsorption resistance in an aqueous medium. These results confirmed that the reasonable design was feasible and significant in designing water-compatible non-covalent imprinted polymers. In addition, the screening strategy of imprinting systems proposed in this study has certain universality and can be widely used to screen various imprinting systems. • 1、Theoretical investigation on the noncovalent MIPs used in aqueous environment. • 2、A modified suspension polymerization was proposed to synthesize CDCA-MIP and. • SPM-MIP. • 3、CDCA-MIP and SPM-MIP had high adsorption capacity, selectivity and reusability. • 4、CDCA-MIP and SPM-MIP showed strong anti-protein adsorption in aqueous environment. .

Hydration and antibiofouling of TMAO-derived zwitterionic polymers surfaces studied with atomistic molecular dynamics simulations

Zwitterionic polymers have emerged as a class of highly effective ultralow fouling materials for critical marine coating and biomedical applications. The recently developed trimethylamine N-oxide (TMAO)-derived zwitterionic polymers have demonstrated excellent antibiofouling capability in various chemical environments; however, it remains unclear how they interact with proteins at the microscopic level. To further investigate the antifouling mechanisms, we performed atomistic molecular dynamics (MD) simulations in combination with free-energy computations to provide an in-depth molecular understanding of the interactions of TMAO polymer brush (pTMAO) surfaces with proteins of opposite charges (positively charged lysozyme and negatively charged barnacle cement protein) in aqueous environments (pure water and saline solution). Our simulations revealed ordered structures of a condensed hydration water layer on the pTMAO surfaces in pure and saline water. The quantitative free energy analyses showed that the pTMAO surface has small protein desorption energy, but with a strong hydration energy barrier near the polymer surfaces to resist protein adsorption compared to other biofouling surfaces. The addition of salts only has a slight effect on the pTMAO surface’s exclusion of proteins due to the small interference of the structure of interfacial water. This study provides detailed knowledge of the strong surface hydration of zwitterionic polymers and its relation to salt impact, protein adsorption, and antibiofouling behavior of these important materials.

RGD Nanoarrays with Nanospacing Gradient Selectively Induce Orientation and Directed Migration of Endothelial and Smooth Muscle Cells.

Directed migration of cells through cell-surface interactions is a paramount prerequisite in biomaterial-induced tissue regeneration. However, whether and how the nanoscale spatial gradient of adhesion molecules on a material surface can induce directed migration of cells is not sufficiently known. Herein, we employed block copolymer micelle nanolithography to prepare gold nanoarrays with a nanospacing gradient, which were prepared by continuously changing the dipping velocity. Then, a self-assembly monolayer technique was applied to graft arginine-glycine-aspartate (RGD) peptides on the nanodots and poly(ethylene glycol) (PEG) on the glass background. Since RGD can trigger specific cell adhesion via conjugating with integrin (its receptor in the cell membrane) and PEG can resist protein adsorption and nonspecific cell adhesion, a nanopattern with cell-adhesion contrast and a gradient of RGD nanospacing was eventually prepared. In vitro cell behaviors were examined using endothelial cells (ECs) and smooth muscle cells (SMCs) as a demonstration. We found that SMCs exhibited significant orientation and directed migration along the nanospacing gradient, while ECs exhibited only a weak spontaneously anisotropic migration. The gradient response was also dependent upon the RGD nanospacing ranges, namely, the start and end nanospacings under a given distance and gradient. The different responses of these two cell types to the RGD nanospacing gradient provide new insights for designing cell-selective nanomaterials potentially used in cell screening, wound healing, etc.

Development and post-functionalization of a colorless universal coating using Bis(vinyl sulfonyl)methane

Herein we reported a colorless universal and stable coating through Bis(vinyl sulfonyl)methane (BVS) polymerization that occurs on a broad range of inorganic and organic material surfaces. A set of organic bases were screened, and 1-methylimidazole was selected as the initiator. Michael addition, polymerization and crosslinking were proposed as the major stages for the coating growth. Hydrophobicity, roughness, film thickness, elemental composition, and post-reaction sites of the coating were characterized by complementary surface analysis techniques. Several functionalized coatings were demonstrated after treatments of the post-reaction sites, including nucleic acid detection, protein adsorption resistance, and biocompatible cell adhesion. Due to the covalent bond between coatings and surfaces, the surface was stable even under ultrasound, in strong acid, or after moist-heat sterilization. Rather than the oily darkness of the polydopamine (PDA) coating, our coatings are transparent to white which is much more visually comfortable for patients and medical personnel. Polybis(vinyl sulfonyl)methane (PBVS) coating provides remarkable visual appealingness, universality, mechanic stability, and easiness in preparation and functionalization for multiple end-users.

Antifouling zwitterionic poly-β-peptides

Zwitterionic polypeptides with homogenous alternating charges draw a great deal of attentions for their antifouling property and biocompatibility. Antifouling zwitterionic polypeptides are synthesized from α-amino acid in previous studies, but with application limitation due to their susceptibility to proteolysis. In this study, we report zwitterionic poly-β-peptides as promising antifouling materials owning to their resistance to proteolysis and easy synthesis. We develop a series of poly-β-peptides, DbaYKY-poly(β-diaminobutyric acid-glutamic acid) (PβDab-E), bearing zwitterionic amino acid in the side chain, combining with a surface-grafting tripeptide motif at the end of the polymer for easily surface functionalization. The PβDab-E can be easily modified to surface to resist protein adsorption, cell adhesion and microbial adhesion to a great extent owning to its strong hydration ability. The convenient surface modification strategy and promising antifouling performance imply PβDab-E great potential for application in the biomedical filed.

Polylactic acid film surface functionalized by zwitterionic poly[2-(methacryloyloxy)ethyl choline phosphate] with improved biocompatibility

Polylactic acid (PLA) is a non-toxic, biodegradable biological material that is widely used in tissue engineering and regenerative medicine. PLA is easy to adsorb non-specific proteins and lacks cell adhesion after implantation. Choline phosphate (CP) is a novel zwitterion with a reverse structure of phosphate choline (PC) on the cell membrane that can form a specific "CP-PC" interaction to promote cell adhesion. In our previous work, modification of choline phosphate polymers (PMCP) onto the PLA film surface improved the hydrophilicity and degradation properties. In this study, we further investigated the biocompatibility of PLA-PMCP films from protein adsorption, cell adhesion and proliferation, bacterial adhesion, blood compatibility, and inflammation in vivo. The PLA-PMCP surface can resist protein adsorption and bacterial adhesion due to the anti-fouling properties of the zwitterion PMCP. Meanwhile, the PLA-PMCP surface promotes the adhesion and proliferation of BMSCs due to the specific "CP-PC" effect. In addition, the PLA-PMCP film has good blood compatibility as well as the PLA film. During in vivo experiments, biocompatibility was improved and the inflammatory response and immune rejection of PLA-PMCP films were reduced compared to those of the original PLA film. Therefore, the PMCP-modified PLA film resists protein adsorption and bacterial adhesion, promotes cell adhesion and proliferation, and has good hemocompatibility and histocompatibility. This brings a significant potential for application in the fields of tissue engineering and regenerative medicine.

Bioinspired antifouling Fe-based amorphous coating via killing-resisting dual surface modifications

Fe-based amorphous coatings with outstanding corrosion resistance are promise for marine applications. However, these coatings encounter a great challenge of biofouling in marine environments. Inspired by the unique micro-nano hierarchical structure of shark skin with excellent antifouling properties, in this paper, we construct a bioinspired Fe-based amorphous coating with killing-resisting dual-effect via proper surface modifications, i.e., the modification with micro-patterned nanostructured Cu2O fibers (killing effect), followed by the modification with superhydrophobic surface (resisting effect). As a result, the modified amorphous coating exhibits impressive antifouling properties, achieving 98.6% resistance to Nitzschia closterium f. minutissima, 87% resistance to Bovine serum albumin protein and 99.8% resistance to Pseudomonas aeruginosa, respectively. The remarkable antifouling performance is attributed to a synergistic antifouling mechanism from both resisting effect and killing effect, wherein the superhydrophobic surface provides a barrier to resist protein adsorption, while the patterned nanostructured Cu2O fibers supply Cu+ ions to kill bacterial cells. In addition, the modified amorphous coating also exhibits excellent mechanical robustness, which ensures the durability of the Fe-based amorphous coating in practical services. This work may promote the development of new durable metal-based coatings integrated with anti-fouling and anti-corrosion properties.