A simple approach for preparing bicomponent polymer patterns was developed by coating polydopamine (PDA) on superhydrophilic poly(2-acryl-amido-2-methylpropane sulfonic acid) (PAMPS) brushes. Well-defined and versatile arrays of proteins and cells were achieved without harm to proteins and cells.

Styrenic thermoplastic elastomers (STPEs), particularly for poly(styrene-b-isobutylene-b-styrene) (SIBS), have aroused great interest in the indwelling and implant applications. However, the biomaterial-associated infection is a great challenge for these hydrophobic elastomers. Here, benzyl chloride (BnCl) groups are initially introduced into the SIBS backbone via Friedel–Crafts chemistry, followed by reaction with methyl 3-(dimethylamino) propionate (MAP) to obtain a cationic carboxybetaine ester-modified elastomer. The as-prepared elastomer is able to kill bacteria efficiently, while upon the hydrolysis of carboxybetaine esters into zwitterionic groups, the resultant surface has antifouling performances against proteins, platelets, erythrocytes, and bacteria. This STPE that switches from bactericidal efficacy during storage to the antifouling property in service has great potential in biomedical applications, and is generally applicable to the other styrene-based polymers.

Bacteria-responsive surfaces popularly exert their smart antibacterial activities by bacteria-triggered delivery of antibacterial agents; however, the antibacterial agents should be additionally reloaded for the renewal of these surfaces. Herein, a reversible, nonleaching bacteria-responsive antibacterial surface is prepared by taking advantage of a hierarchical polymer brush architecture. In this hierarchical surface, a pH-responsive poly(methacrylic acid) (PMAA) outer layer serves as an actuator modulating the surface behavior on demand, while antimicrobial peptides (AMP) are covalently immobilized on the inner layer. The PMAA hydration layer renders the hierarchical surface resistant to initial bacterial attachment and biocompatible under physiological conditions. When bacteria colonize the surface, the bacteria-triggered acidification allows the outermost PMAA chains to collapse, therefore exposing the underlying bactericidal AMP to on-demand kill bacteria. In addition, the dead bacteria can be released once the PMAA chains resume their hydrophilicity because of the environmental pH increase. The functionality of the nonleaching surface is reversible without additional reloading of the antibacterial agents. This approach provides a new methodology for the development of smart surfaces in a variety of practical biomedical applications.Keywords: bacteria-responsive; cationic antimicrobial peptides; hierarchical architecture; pH-responsive polymer; smart surfaces

Infection and thrombosis associated with medical implants cause significant morbidity and mortality worldwide. As we know, current technologies to prevent infection and thrombosis may cause severe side effects. To overcome these complications without using antimicrobial and anticoagulant drugs, we attempt to prepare a liquid-infused poly(styrene-b-isobutylene-b-styrene) (SIBS) microfiber coating, which can be directly coated onto medical devices. Notably, the SIBS microfiber was fabricated through solution blow spinning. Compared to electrospinning, the solution blow spinning method is faster and less expensive, and it is easy to spray fibers onto different targets. The lubricating liquids then wick into and strongly adhere the microfiber coating. These slippery coatings can effectively suppress blood cell adhesion, reduce hemolysis, and inhibit blood coagulation in vitro. In addition, Pseudomonas aeruginosa (P. aeruginosa) on the lubricant infused coatings slides readily, and no visible residue is left after tilting. We furthermore confirm that the lubricants have no effects on bacterial growth. The slippery coatings are also not cytotoxic to L929 cells. This liquid-infused SIBS microfiber coating could reduce the infection and thrombosis of medical devices, thus benefiting human health.Keywords: antibacterial; hemocompatibility; microfiber; slippery coating; solution blow spinning; thermoplastic elastomer

A facile, low-cost and time-saving method was proposed to prepare antibacterial polyurethane-g-polyethylene glycol (TPU-g-PEG) nanofiber composite by anchoring silver nanoparticles (AgNP) onto nanofibers via ultrasonication assistance. Firstly, antifouling PEG as bacteria-repelling component was chemically grafted onto TPU nanofibers through UV photo-graft polymerization to obtain TPU-g-PEG nanofibers; then AgNP as bactericidal component were immobilized onto the TPU-g-PEG nanofibers under the assistance of ultrasonication. Even if the nanofibers were immersed into PBS solution and incubated for 7 days, the released content of AgNP characterized by ICP-MS was 2.688 μg which was much lower than that of reference reported method. The TPU-g-PEG/Ag nanofiber composites exhibited excellent hemocompatibility, including suppression of platelet and red blood cell adhesion, the lower hemolysis ratios, and the higher blood clotting index. Importantly, the as-prepared nanofiber composites performed better antibacterial properties in vitro assays employing gram negative and positive strains, because of the bacterial resistance of the grafted PEG and the bactericidal effect of silver. Our approach has significant potential for the development of infection-resistant wound dressing.

The discovery of antibacterial functions for carbon nanotubes (CNT) has triggered great interest because of the excellent antibacterial properties of CNT. However, there are two obstacles, i.e., cell toxicity and CNT aggregation in a polymer matrix, which greatly limit the antibacterial application of CNT in medical devices. In this study, a facile, cost-effective, time-saving and environmentally friendly approach was proposed to impart the antibacterial property to thermoplastic polyurethane (TPU) electrospun nanofibers with CNT. The ultrasonication technique was explored to in situ anchor the CNT onto the TPU electrospun nanofibers to achieve the bactericidal property. This effectively circumvented the aggregation of CNT when the TPU/CNT electrospun nanofibers were prepared. In addition, the anchor preparation was efficient taking only 10 min to complete and it was also non-toxic because the green solvent ethanol was used as the dispersion solvent. PEG was chemically grafted onto the TPU (TPU-g-PEG) electrospun nanofibers through UV photo-graft polymerization. Although CNT exhibit a good bactericidal property, they could be toxic to human cells. Incorporation of PEG could not only effectively reduce the toxicity of CNT to the human cells but also decrease bacterial attachment. The TPU-g-PEG/CNT nanofibers exhibited excellent hemocompatibility, including suppression of red blood cell adhesion, and lower hemolysis ratios. Importantly, the as-prepared nanofibers had better antibacterial properties due to the bacterial resistance of the grafted PEG and the bactericidal effect of CNT. Our facile approach has significant potential for the infection-resistant wound dressing.

Although polycationic surfaces have high antimicrobial efficacies, they suffer from high toxicity to mammalian cells and severe surface accumulation of dead bacteria. For the first time, we propose a surface-initiated photoiniferter-mediated polymerization (SI-PIMP) strategy of constructing a “cleaning” zwitterionic outer layer on a polycationic bactericidal background layer to physically hinder the availability of polycationic moieties for mammalian cells in aqueous service. In dry conditions, the polycationic layer exerts the contact-active bactericidal property toward the adherent bacteria, as the zwitterionic layer collapses. In aqueous environment, the zwitterionic layer forms a hydration layer to significantly inhibit the attachment of planktonic bacteria and the accumulation of dead bacteria, while the polycationic layer kills bacteria occasionally deposited on the surface, thus preserving the antibacterial capability for a long period. More importantly, the zwitterionic hydrated layer protects the mammalian cells from toxicity induced by the bactericidal background layer, and therefore hierarchical antibacterial surfaces present much better biocompatibility than that of the naked cationic references. The dominant antibacterial mechanism of the hierarchical surfaces can switch from the bactericidal efficacy in dry storage to the bacteria repellent capability in aqueous service, showing great advantages in the infection-resistant applications.

Infections associated with medical devices cause significant costs, morbidity, and mortality. Medical devices with hemocompatibility, antioxidative stress, and antibacterial properties are difficult to fabricate. In this study, silver nanoparticles (Ag NPs) were synthesized for the first time in the presence of carboxylic D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) as antibacterial agents. The Ag NPs were characterized by UV-visible spectroscopy, transmission electron microscopy, and zeta potential measurements. The results showed that Ag NPs had a good dispersion stability and uniform size distribution. The introduction of TPGS dispersed the Ag NPs in solution and provided active protection against Ag NP-induced free radical damage. N-Isopropylacrylamide (NIPAAm) and N-(3-aminopropyl) methacrylamide hydrochloride (APMA) were then co-grafted onto polypropylene (PP) membranes by ultraviolet grafting, which can provide antifouling properties. The modified PP surface can be used as a platform to load the Ag NPs capped with TPGS. The loading efficiency of Ag NPs was mediated by electrostatic interactions between the positively charged APMA and the negatively charged Ag NPs. The loaded TPGS can slow the lipid peroxidation of erythrocytes and fill the lipid bilayer of erythrocytes to prevent antioxidative stress and hemolysis. The bacteria adhesion, bacterial activity, and biofilm formation proved that the modified PP surfaces loaded with Ag NPs had excellent antibacterial and bactericidal properties. Therefore, our approach can serve as a basis for developing medical devices with excellent hemocompatibility, as well as simultaneous antioxidative and antibacterial properties, thereby providing a potential prevention measure of medical-device-associated infections.

The hemolysis of erythrocytes is a big obstacle to the development of new non-plasticizer polymer containers for erythrocyte preservation. To construct a long-term anti-hemolytic surface of a plasticizer-free polymer, we coaxially electrospin core–shell structured D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS)/poly(ethylene oxide) nanofibers on the surface of a styrene-b-(ethylene-co-butylene)-b-styrene (SEBS) elastomer that is covered with grafted poly(ethylene glycol) (PEG) chains. Our strategy is based on the fact that the grafted layers of PEG reduce mechanical damage to red blood cells (RBCs) while the TPGS released from the nanofibers on a blood-contacting surface can act as an antioxidant to protect RBCs from oxidative damage. We demonstrate that TPGS/PEO core–shell structured nanofibers have been well prepared on the surface of PEG modified SEBS; the controlled release of TPGS in distilled water is obtained and the release can last for almost 4 days at 4 °C; during RBC preservation, TPGS acts as the antioxidant to decrease the membrane oxidation and hemolysis of RBCs. Our work paves a new way for the development of non-plasticizer polymers for RBC preservation, which may be helpful for the fabrication of long-term anti-hemolytic biomaterials in vivo.

A platform for capture and release of drug-loaded red blood cells (RBCs) is demonstrated by utilizing polymer grafted superhydrophobic polypropylene (PP). Combined with micro/nanobinary structures, thermoresponsive polymers, and lectin–saccharides recognition, this platform enables highly efficient capture and release of RBCs loaded with nattokinase, which endows PP with potent fibrinolytic ability.

We propose a facile UV strategy to construct a hierarchically three-dimensional (3D) substrate that comprises a polystyrene (PS) microsphere layer on the cycloolefin polymer (COP) substrate and densely packed hydrophilic polymer brushes grafting from this 3D backbone. This hierarchical substrate gives a high antibody loading capacity and 3D manner of analyte capture, therefore enhancing detection signal while reducing background noise.

Despite the advanced modern biotechniques, thrombosis and bacterial infection of biomedical devices remain common complications that are associated with morbidity and mortality. Most antifouling surfaces are in solid form and cannot simultaneously fulfill the requirements for antithrombosis and antibacterial efficacy. In this work, we present a facile strategy to fabricate a slippery surface. This surface is created by combining photografting polymerization with osmotically driven wrinkling that can generate a coarse morphology, and followed by infusing with fluorocarbon liquid. The lubricant-infused wrinkling slippery surface can greatly prevent protein attachment, reduce platelet adhesion, and suppress thrombus formation in vitro. Furthermore, E. coli and S. aureus attachment on the slippery surfaces is reduced by ∼98.8% and ∼96.9% after 24 h incubation, relative to poly(styrene-b-isobutylene-b-styrene) (SIBS) references. This slippery surface is biocompatible and has no toxicity to L929 cells. This surface-coating strategy that effectively reduces thrombosis and the incidence of infection will greatly decrease healthcare costs.Keywords: antibacterial; antifouling; photografting polymerization; poly(styrene-b-isobutylene-b-styrene) (SIBS); slippery surface

A novel hydrophilic PAMPS–PAAm brush pattern is fabricated to selectively capture blood cells from whole blood. PAMPS brushes provide antifouling surfaces to resist protein and cell adhesion while PAAm brushes effectively entrap targeted proteins for site-specific and cell-type dependent capture of blood cells.

•The blood-contacting surface was constructed by coaxial electrospinnig of (ascorbic acid and lecithin)/PEO core–shell nanofibers onto the surface of PEG-grafted SEBS.•Ascorbic acid and lecithin could release from the nanofibers and interact with erythrocyte to reduce oxidation and lipid loss of the stored erythrocyte, resulting in low mechanical fragility and hemolysis of stored erythrocyte.•Our work paved new way to fabricate biomaterials with the capability of long-term anti-hemolysis.There is an urgent need to develop blood-contacting biomaterials with long-term anti-hemolytic capability. To obtain such biomaterials, we coaxially electrospin [ascorbic acid (AA) and lecithin]/poly (ethylene oxide) (PEO) core–shell nanofibers onto the surface of styrene-b-(ethylene-co-butylene)-b-styrene elastomer (SEBS) that has been grafted with poly (ethylene glycol) (PEG) chains. Our strategy is based on that the grafted layers of PEG render the surface hydrophilic to reduce the mechanical injure to red blood cells (RBCs) while the AA and lecithin released from nanofibers on blood-contacting surface can actively interact with RBCs to decrease the oxidative damage to RBCs. We demonstrate that (AA and lecithin)/PEO core–shell structured nanofibers have been fabricated on the PEG grafted surface. The binary release of AA and lecithin in the distilled water is in a controlled manner and lasts for almost 5 days; during RBCs preservation, AA acts as an antioxidant and lecithin as a lipid supplier to the membrane of erythrocytes, resulting in low mechanical fragility and hemolysis of RBCs, as well as high deformability of stored RBCs. Our work thus makes a new approach to fabricate blood-contacting biomaterials with the capability of long-term anti-hemolysis.

•Chitosan was modified with carboxybetaine ester brush via a ‘click’-type azlactone reaction.•The as-prepared CS switched from bactericidal during storage to antifouling before service.•The as-modified wound dressing has great potential in biomedical applications.A facile approach to functionalize chitosan (CS) non-woven surface with the bactericidal and antifouling switchable moieties is presented. Azlactone-cationic carboxybetaine ester copolymer was firstly prepared, then chemically attached onto CS non-woven surface through the fast and efficient ‘click’-type interfacial reaction between CS primary amines and azlactone moieties. The CS non-woven surface functionalized with cationic carboxybetaine esters is able to kill bacteria effectively. Upon the hydrolysis of carboxybetaine esters into zwitterionic groups, the resulting zwitterionic surface can further prevent the attachment of proteins, platelets, erythrocytes and bacteria. This CS non-woven that switches from bactericidal performance during storage to antifouling property before its service has great potential in wound dressing applications.

The construction of biocompatible and antibacterial surfaces is becoming increasingly important. However, most of the existing techniques require multi-step procedures, stringent conditions and specific substrates. We present here a facile method to create a biocompatible and antibacterial surface on virtually any substrate under ambient conditions. The strategy is based on casting a highly adherent elastomer, styrene-b-(ethylene-co-butylene)-b-styrene, from a solvent mixture of xylene and decanol, in which decanol acts as both a polymer precipitator to induce phase separation and a liquid template to stabilize the superhydrophobic structure. The stable and durable superhydrophobic surface shows good biocompatibility and antibacterial properties.

Contrary to a prevailing concept on protein adsorption and cell adhesion, novel micropatterned polyacrylamide (PAAm) brushes that can resist cell adhesion but promote protein retention are created through patterning of ATRP initiators and surface-initiated ATRP on a polymer substrate.

Detection of dysfunctional and apoptotic cells plays an important role in clinical diagnosis and therapy. To develop a portable and user-friendly platform for dysfunctional and aging cell detection, we present a facile method to construct 3D patterns on the surface of styrene-b-(ethylene-co-butylene)-b-styrene elastomer (SEBS) with poly(ethylene glycol) brushes. Normal red blood cells (RBCs) and lysed RBCs (dysfunctional cells) are used as model cells. The strategy is based on the fact that poly(ethylene glycol) brushes tend to interact with phosphatidylserine, which is in the inner leaflet of normal cell membranes but becomes exposed in abnormal or apoptotic cell membranes. We demonstrate that varied patterned surfaces can be obtained by selectively patterning atom transfer radical polymerization (ATRP) initiators on the SEBS surface via an aqueous-based method and growing PEG brushes through surface-initiated atom transfer radical polymerization. The relatively high initiator density and polymerization temperature facilitate formation of PEG brushes in high density, which gives brushes worm-like morphology and superhydrophilic property; the tendency of dysfunctional cells adhered on the patterned surfaces is completely different from well-defined arrays of normal cells on the patterned surfaces, providing a facile method to detect dysfunctional cells effectively. The PEG-patterned surfaces are also applicable to detect apoptotic HeLa cells. The simplicity and easy handling of the described technique shows the potential application in microdiagnostic devices.Keywords: 3D patterned surface; dysfunctional cell detection; phosphatidylserine; poly(ethylene glycol) brushes; superhydrophilicity

Hydrophobic thermoplastic elastomers, e.g., poly(styrene-b-isobutylene-b-styrene) (SIBS), have found various in vivo biomedical applications. It has long been recognized that biomaterials can be adversely affected by bacterial contamination and clinical infection. However, inhibiting bacterial colonization while simultaneously preserving or enhancing tissue-cell/material interactions is a great challenge. Herein, SIBS substrates were functionalized with nucleases under mild conditions, through polycarboxylate grafts as intermediate. It was demonstrated that the nuclease-modified SIBS could effectively prevent bacterial adhesion and biofilm formation. Cell adhesion assays confirmed that nuclease coatings generally had no negative effects on L929 cell adhesion, compared with the virgin SIBS reference. Therefore, the as-reported nuclease coating may present a promising approach to inhibit bacterial infection, while preserving tissue-cell integration on polymeric biomaterials.Keywords: antibacterial; cell adhesion; deoxyribonuclease (DNase); poly(styrene-b-isobutylene-b-styrene) (SIBS); ribonuclease (RNase)

Hemocompatibility and oxidative stress are significant for blood-contacting devices. In this study, N-isopropylacrylamide (NIPAAm) and N-(3-aminopropyl)methacrylamide hydrochloride (APMA) were cografted on polypropylene (PP) membrane using ultraviolet grafting to load antioxidative d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) and control the release of TPGS. The immobilization of NIPAAm and APMA onto PP membrane was confirmed by attenuated total reflectance Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy. Combined with data from platelet adhesion, red blood cell (RBC) attachment, and hemolysis rate, the hemocompatibility of PP was significantly improved. An in-depth characterization using hemolysis rate test, scanning electron microscopy, atomic force microscopy, and confocal laser scanning microscopy was conducted to confirm that the mechanism of the release of TPGS interacted with RBCs was different at different stages. The release of TPGS from the loading PP membranes affected hemolysis at different stages. At the early stage of release, TPGS maintained the tiny (nanometer-sized) tubers on the membrane surface and enhanced the membrane permeabilization by generating nanosized pores on the cell membranes. Afterward, the incorporated TPGS slowed the lipid peroxidation of erythrocytes and filled in the lipid bilayer of erythrocyte to prevent hemolysis. Thus, the approach implemented to graft NIPAAm and APMA and load TPGS was suitable to develop medical device with excellent hemocompatibility and antioxidative property.Keywords: antioxidative; controlled release; d-α-tocopheryl polyethylene glycol 1000 succinate; polypropylene nonwoven fabric membrane; responsive polymer brush

The development of technologies for a biomedical detection platform is critical to meet the global challenges of various disease diagnoses. In this study, an inert cycloolefin polymer (COP) support was modified with two-layer polymer brushes possessing dual functions, i.e., a low fouling poly[poly(ethylene glycol) methacrylate] [p(PEGMA)] bottom layer and a poly(acrylic acid) (PAA) upper layer for antibody loading, via a surface-initiated photoiniferter-mediated polymerization strategy for fluorescence-based immunoassay. It was demonstrated through a confocal laser scanner that, for the as-prepared COP-g-PEG-b-PAA-IgG supports, nonspecific protein adsorption was suppressed, and the resistance to nonspecific protein interference on antigen recognition was significantly improved, relative to the COP-g-PAA-IgG references. This strategy for surface modification of a polymeric platform is also applicable to the fabrication of other biosensors.Keywords: antibody immobilization; cycloolefin polymer (COP); hierarchical architecture; immunoassay; surface-initiated photoiniferter-mediated polymerization (SI-PIMP);

Hemolysis of red blood cells (RBCs) caused by implant devices in vivo and nonpolyvinyl chloride containers for RBC preservation in vitro has recently gained much attention. To develop blood-contacting biomaterials with long-term antihemolysis capability, we present a facile method to construct a hydrophilic, 3D hierarchical architecture on the surface of styrene-b-(ethylene-co-butylene)-b-styrene elastomer (SEBS) with poly(ethylene oxide) (PEO)/lecithin nano/microfibers. The strategy is based on electrospinning of PEO/lecithin fibers onto the surface of poly [poly(ethylene glycol) methyl ether methacrylate] [P(PEGMEMA)]-modified SEBS, which renders SEBS suitable for RBC storage in vitro. We demonstrate that the constructed 3D architecture is composed of hydrophilic micro- and nanofibers, which transforms to hydrogel networks immediately in blood; the controlled release of lecithin is achieved by gradual dissolution of PEO/lecithin hydrogels, and the interaction of lecithin with RBCs maintains the membrane flexibility and normal RBC shape. Thus, the blood-contacting surface reduces both mechanical and oxidative damage to RBC membranes, resulting in low hemolysis of preserved RBCs. This work not only paves new way to fabricate high hemocompatible biomaterials for RBC storage in vitro, but provides basic principles to design and develop antihemolysis biomaterials for implantation in vivo.Keywords: blood-contacting surface; controlled release; electrospinning; hemolysis; lecithin;

Platelets have exhibited capabilities beyond clotting in recent years. Most of their functions are related to the nature of platelet adhesion. Establishing a facile method to understand the platelet adhesion and assess the platelet function through the mechanism and mechanics of adhesion is highly desired. Here, we report a generally applicable UV lithography technique with a photomask, which performs selective surface functionalization on large substrate areas, for creating stable, physical adhesive sites in the range of 12 μm to 3 μm. Our study demonstrated that the patterned surface facilitated probing of single platelet adhesion in a quantitative manner, and rendered platelets sensitive to adhesive proteins even at a low protein concentration. In addition, the platelet function in the presence of antiplatelet (anticancer) agents on platelets could be accurately estimated based on single platelet adhesion (SPA). This work paves a new way to understand and assess the blood platelet function. The SPA assay methodology has the potential to enable a rapid, accurate point-of-care platform suitable for evaluation of platelet function, detection of dysfunctional platelets, and assay of drug effects on platelets in cancer patients.

Bovine serum albumin (BSA) modified polypropylene (PP) was fabricated via surface-initiated atom transfer radical polymerization (SI-ATRP) of poly(ethylene glycol) methacrylate (PEGMA) and glycidyl methacrylate (GMA). Kinetics study revealed an approximately linear increase in graft density of the functional brushes with polymerization time. Attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy confirmed that comonomers and BSA were successfully immobilized onto PP film. The hydrophilicity of PP was improved by modification with PEGMA and GMA. The balance between the inhibition of BSA adsorption by PEGMA and the covalent immobilization of BSA by GMA through the ring-opening reaction of the epoxy group resulted in the moderate fluorescence intensity of FITC–BSA immobilized PP-g-P (PEGMA-co-GMA). The hemolysis test showed that BSA could decrease the hemolysis rate. Red blood cell membrane maximal stress can be reduced by the inertness of BSA as well as the repulsion caused by its electrostatic interactions. Whole blood cell attachment tests showed that BSA molecules weakened the interaction between blood cells and the PP surface. Therefore, the immobilization of BSA on PP film is an effective approach for improving the hemocompatibility of PP.

Inert cycloolefin polymers (COPs), which possess excellent optical properties, are a series of ideal materials for fabricating cheap disposable biosensor platforms. However, their antibioadhesion properties are expected to be improved prior to their application as biosensor supports. In this study, for the first time the COP supports were modified with well-controlled neutral, anionic and cationic polymer brushes via surface-initiated photoiniferter-mediated polymerization. This graft polymerization was confirmed by infrared spectroscopy, and X-ray photoelectron spectroscopy. The antibioadhesion properties of the modified supports were evaluated through a series of biological experiments. It was found that among these modified samples, the anionic poly(2-carboxyethyl acrylate)-modified COP supports presented the best antibioadhesion performances, i.e., suppressing protein adsorption, platelet adhesion and red blood cell attachment.

The biostable poly(styrene-b-isobutylene-b-styrene) (SIBS) elastomers are well-known for their large-scale in vivo application as drug-eluting coatings in coronary stents. In this study, the SIBS elastomers were modified with a poly(dopamine) (PDA) adherent layer, followed by integrating both chitosan (CS) and hyaluronic acid (HA) onto their surfaces. The as-prepared samples (SIBS-CS-g-HA) presented excellent cytocompatibility because CS facilitates cell attachment and HA enhances cell proliferation. The initial adhesion test of E. coli on SIBS-CS-g-HA showed effective antiadhesive properties. The in vitro antibacterial test confirmed that SIBS-CS-g-HA has good antibacterial activity.

•Graphene/SEBS-g-MAH nanocomposites were prepared by solution mixing.•Good interfacial interaction was obtained by the “grafting to” method in the nanocomposite.•Enhanced electrical, mechanical properties were observed for the nanocomposite.Graphene was first surface modified with octadecylamine to prevent the aggregation of graphene itself and also improve the compatibility between the graphene and polymer matrix. Then it was solution mixed with SEBS grafted with maleic anhydride (SEBS-g-MAH) to prepare graphene/SEBS-g-MAH nanocomposites. FTIR results show that esterification reaction took place by a “grafting to” method between maleic anhydride group of SEBS-g-MAH and the residual hydroxyl of graphene. Rheological data indicated that storage modulus increased sharply with 0.5 wt% addition content of graphene, due to forming the network of graphene in SEBS-g-MAH. The tensile strength was enhanced by 69%, ranging from 1.94 to 3.28 MPa. The alternating current conductivity at 1 Hz of nanocomposites increased from 2.5 ×10−16 to 1.2×10−11 S/cm, compared with that of SEBS-g-MAH. The above results were attributed to the good dispersion of graphene in SEBS-g-MAH matrix and interfacial chemical interaction between graphene and SEBS-g-MAH.

•Poly(cyclooctene)-g-poly(ethylene glycol) graft copolymers are synthesized.•Both the PEG side chain length and content are tunable.•Surface roughness affects the protein resistant property of the copolymer film.•Copolymer with 60 wt.% PEG (750 g/mol) has the best protein resistant property.In our previous work [H. Shi, D. Shi et al., Polymer Chemistry 2(2011)679–684], polycyclooctene-g-PEG (PCOE-g-PEG) copolymers were synthesized via ring opening metathesis polymerization (ROMP) from PEG functionalized cyclic olefin macromonomers and cyclooctene. The grafting degree and the grafting site were easily controlled through the “grafting through” approach. The PCOE-g-PEG film surface was imparted excellent anti-protein adsorption properties. In that work, the molecular weight of PEG side chain was fixed at 750 g/mol and the neat PEG content in the copolymer was lower than 50 wt.%. In this work, both the effects of PEG side chain lengths (350 to 1000 g/mol) at a fixed PEG content (50 wt.%) and the neat PEG content (30 wt.% to 70 wt.%) at a fixed PEG molecular weight (750 g/mol) on the anti-protein adsorption and anti-platelet adhesion properties are studied. It is shown that the copolymer with 60 wt.% PEG side chains of 750 g/mol, where both PEG and PCOE form continuous morphology, is optimal to reduce the adsorption of both the bovine serum albumin (BSA) and platelet. When the PEG content reaches 70 wt.%, phase inversion happens. PEG is the continuous phase but PCOE becomes the dispersed phase. The surface roughness of the casting PCOE-g-PEG film increases. In this case, both BSA adsorption and platelet adhesion will slightly increase comparing to the sample with 60 wt.% PEG.

Despite the importance of adhesion between electrospun meshes and substrates, the knowledge on adhesion mechanism and the method to improve the adhesion remain limited. Here, we precisely design the model system based on electrospun poly(ethylene oxide) (PEO) meshes and the substrate of styrene-b-(ethylene-co-butylene)-b-styrene elastomer (SEBS), and quantitatively measure the adhesion with a weight method. The surfaces of SEBS with different roughness are obtained by casting SEBS solution on the smooth and rough glass slides, respectively. Then, the surfaces of casted SEBS are respectively grafted with PEG oligomers and long PEG chains much larger than the entanglement molecular weight by surface-initiated atom transfer radical polymerization (SI-ATRP) of poly(ethylene glycol) methyl ether methacrylate (PEGMA). The detached surfaces of SEBS and electrospun fibers after adhesion measurements are analyzed by scanning electron microscopy (SEM). The adhesive force and adhesion energy are found to lie in the range from 68 to 220 mN and from 12 to 46 mJ/m2, respectively, which are slightly affected by surface roughness of substrate but mainly determined by surface interactions. Just as the chemical cross-linking induces the strong adhesion, the chain entanglements on the interface lead to the higher adhesion than those generated by hydrophilic–hydrophobic interactions and hydrophilic interactions. The long grafted chains and the enhanced temperature facilitate the chain entanglements, resulting in the strong adhesive force. This work sheds new light on the adhesion mechanism at molecular level, which may be helpful to improve the adhesion between the electrospun fibers and substrates in an environmentally friendly manner.

Development of technologies for biomedical detection platform is critical to meet the global challenges of various disease diagnoses, especially for point-of-use applications. Because of its natural simplicity, effectiveness, and easy repeatability, random covalent-binding technique is widely adopted in antibody immobilization. However, its antigen-binding capacity is relatively low when compared to site-specific immobilization of antibody. Herein, we report that a detection platform modified with boronic acid (BA)-containing sulfobetaine-based polymer brush. Mainly because of the advantage of oriented immobilization of antibody endowed with BA-containing three-dimensional polymer brush architecture, the platform had a high antigen-binding capacity. Notably, nonspecific protein adsorption was also suppressed by the zwitterionic pendants, thus greatly enhanced signal-to-noise (S/N) values for antigen recognition. Furthermore, antibodies captured by BA pendants could be released in dissociation media. This new platform is promising for potential applications in immunoassays.Keywords: antibody immobilization; atom transfer radical polymerization (ATRP); boronic acid (BA); immunoassay; zwitterionic-based materilals;

A simple approach for preparing bicomponent polymer patterns was developed by coating polydopamine (PDA) on superhydrophilic poly(2-acryl-amido-2-methylpropane sulfonic acid) (PAMPS) brushes. Well-defined and versatile arrays of proteins and cells were achieved without harm to proteins and cells.

Platelets have exhibited capabilities beyond clotting in recent years. Most of their functions are related to the nature of platelet adhesion. Establishing a facile method to understand the platelet adhesion and assess the platelet function through the mechanism and mechanics of adhesion is highly desired. Here, we report a generally applicable UV lithography technique with a photomask, which performs selective surface functionalization on large substrate areas, for creating stable, physical adhesive sites in the range of 12 μm to 3 μm. Our study demonstrated that the patterned surface facilitated probing of single platelet adhesion in a quantitative manner, and rendered platelets sensitive to adhesive proteins even at a low protein concentration. In addition, the platelet function in the presence of antiplatelet (anticancer) agents on platelets could be accurately estimated based on single platelet adhesion (SPA). This work paves a new way to understand and assess the blood platelet function. The SPA assay methodology has the potential to enable a rapid, accurate point-of-care platform suitable for evaluation of platelet function, detection of dysfunctional platelets, and assay of drug effects on platelets in cancer patients.

A novel hydrophilic PAMPS–PAAm brush pattern is fabricated to selectively capture blood cells from whole blood. PAMPS brushes provide antifouling surfaces to resist protein and cell adhesion while PAAm brushes effectively entrap targeted proteins for site-specific and cell-type dependent capture of blood cells.

We propose a facile UV strategy to construct a hierarchically three-dimensional (3D) substrate that comprises a polystyrene (PS) microsphere layer on the cycloolefin polymer (COP) substrate and densely packed hydrophilic polymer brushes grafting from this 3D backbone. This hierarchical substrate gives a high antibody loading capacity and 3D manner of analyte capture, therefore enhancing detection signal while reducing background noise.

Styrenic thermoplastic elastomers (STPEs), particularly for poly(styrene-b-isobutylene-b-styrene) (SIBS), have aroused great interest in the indwelling and implant applications. However, the biomaterial-associated infection is a great challenge for these hydrophobic elastomers. Here, benzyl chloride (BnCl) groups are initially introduced into the SIBS backbone via Friedel–Crafts chemistry, followed by reaction with methyl 3-(dimethylamino) propionate (MAP) to obtain a cationic carboxybetaine ester-modified elastomer. The as-prepared elastomer is able to kill bacteria efficiently, while upon the hydrolysis of carboxybetaine esters into zwitterionic groups, the resultant surface has antifouling performances against proteins, platelets, erythrocytes, and bacteria. This STPE that switches from bactericidal efficacy during storage to the antifouling property in service has great potential in biomedical applications, and is generally applicable to the other styrene-based polymers.

The hemolysis of erythrocytes is a big obstacle to the development of new non-plasticizer polymer containers for erythrocyte preservation. To construct a long-term anti-hemolytic surface of a plasticizer-free polymer, we coaxially electrospin core–shell structured D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS)/poly(ethylene oxide) nanofibers on the surface of a styrene-b-(ethylene-co-butylene)-b-styrene (SEBS) elastomer that is covered with grafted poly(ethylene glycol) (PEG) chains. Our strategy is based on the fact that the grafted layers of PEG reduce mechanical damage to red blood cells (RBCs) while the TPGS released from the nanofibers on a blood-contacting surface can act as an antioxidant to protect RBCs from oxidative damage. We demonstrate that TPGS/PEO core–shell structured nanofibers have been well prepared on the surface of PEG modified SEBS; the controlled release of TPGS in distilled water is obtained and the release can last for almost 4 days at 4 °C; during RBC preservation, TPGS acts as the antioxidant to decrease the membrane oxidation and hemolysis of RBCs. Our work paves a new way for the development of non-plasticizer polymers for RBC preservation, which may be helpful for the fabrication of long-term anti-hemolytic biomaterials in vivo.

The construction of biocompatible and antibacterial surfaces is becoming increasingly important. However, most of the existing techniques require multi-step procedures, stringent conditions and specific substrates. We present here a facile method to create a biocompatible and antibacterial surface on virtually any substrate under ambient conditions. The strategy is based on casting a highly adherent elastomer, styrene-b-(ethylene-co-butylene)-b-styrene, from a solvent mixture of xylene and decanol, in which decanol acts as both a polymer precipitator to induce phase separation and a liquid template to stabilize the superhydrophobic structure. The stable and durable superhydrophobic surface shows good biocompatibility and antibacterial properties.

A platform for capture and release of drug-loaded red blood cells (RBCs) is demonstrated by utilizing polymer grafted superhydrophobic polypropylene (PP). Combined with micro/nanobinary structures, thermoresponsive polymers, and lectin–saccharides recognition, this platform enables highly efficient capture and release of RBCs loaded with nattokinase, which endows PP with potent fibrinolytic ability.

Infections associated with medical devices cause significant costs, morbidity, and mortality. Medical devices with hemocompatibility, antioxidative stress, and antibacterial properties are difficult to fabricate. In this study, silver nanoparticles (Ag NPs) were synthesized for the first time in the presence of carboxylic D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) as antibacterial agents. The Ag NPs were characterized by UV-visible spectroscopy, transmission electron microscopy, and zeta potential measurements. The results showed that Ag NPs had a good dispersion stability and uniform size distribution. The introduction of TPGS dispersed the Ag NPs in solution and provided active protection against Ag NP-induced free radical damage. N-Isopropylacrylamide (NIPAAm) and N-(3-aminopropyl) methacrylamide hydrochloride (APMA) were then co-grafted onto polypropylene (PP) membranes by ultraviolet grafting, which can provide antifouling properties. The modified PP surface can be used as a platform to load the Ag NPs capped with TPGS. The loading efficiency of Ag NPs was mediated by electrostatic interactions between the positively charged APMA and the negatively charged Ag NPs. The loaded TPGS can slow the lipid peroxidation of erythrocytes and fill the lipid bilayer of erythrocytes to prevent antioxidative stress and hemolysis. The bacteria adhesion, bacterial activity, and biofilm formation proved that the modified PP surfaces loaded with Ag NPs had excellent antibacterial and bactericidal properties. Therefore, our approach can serve as a basis for developing medical devices with excellent hemocompatibility, as well as simultaneous antioxidative and antibacterial properties, thereby providing a potential prevention measure of medical-device-associated infections.

Contrary to a prevailing concept on protein adsorption and cell adhesion, novel micropatterned polyacrylamide (PAAm) brushes that can resist cell adhesion but promote protein retention are created through patterning of ATRP initiators and surface-initiated ATRP on a polymer substrate.