Surface Deformation of Biocompatible Materials: Recent Advances in Biological Applications

The surface topography of substrates is a crucial factor that determines the interaction with biological materials in bioengineering research. Therefore, it is important to appropriately modify the surface topography according to the research purpose. Surface topography can be fabricated in various forms, such as wrinkles, creases, and ridges using surface deformation techniques, which can contribute to the performance enhancement of cell chips, organ chips, and biosensors. This review provides a comprehensive overview of the characteristics of soft, hard, and hybrid substrates used in the bioengineering field and the surface deformation techniques applied to the substrates. Furthermore, this review summarizes the cases of cell-based research and other applications, such as biosensor research, that utilize surface deformation techniques. In cell-based research, various studies have reported optimized cell behavior and differentiation through surface deformation, while, in the biosensor and biofilm fields, performance improvement cases due to surface deformation have been reported. Through these studies, we confirm the contribution of surface deformation techniques to the advancement of the bioengineering field. In the future, it is expected that the application of surface deformation techniques to the real-time interaction analysis between biological materials and dynamically deformable substrates will increase the utilization and importance of these techniques in various fields, including cell research and biosensors.

Hierarchical Surface Architecture of Hemodialysis Membranes for Eliminating Homocysteine Based on the Multifunctional Role of Pyridoxal 5'-phosphate

Patients with end-stage renal disease are prone to developing a complication of hyperhomocysteinemia, manifesting as an elevation of the homocysteine (Hcy) concentration in human plasma. However, Hcy as a protein-bound toxin is barely removed by conventional hemodialysis membranes. Here, we report a novel hemodialysis membrane by preparing a bioactive coating of pyridoxal 5'-phosphate (PLP) and adding biocompatible hyperbranched polyglycerol (HPG) brushes to achieve Hcy removal. The dip-applied PLP coating, a coenzyme with a role in Hcy metabolism, dramatically promoted a decrease in the Hcy concentration in human plasma. Moreover, the aldehyde group of PLP had an intrinsic chemical reactivity toward the terminal amino group to immobilize the HPG brushes on the hemodialysis membrane surface. The hierarchical PLP-HPG layer-functionalized membranes had a high efficacy for eliminating Hcy, with a concentration from the initial stage of 150 μmol/L reduced to a nearly normal level of 20 μmol/L in simulated dialysis. By analyzing the impact of HPG brushes with various chain lengths, we found that HPG brushes with a medium length enabled the PLP coating with the bioactive function of Hcy conversion to additionally protect Hcy-attacked target cells by providing excellent hydrophilicity and a dense enough chain volume overlap of the hyperbranched architecture. Simultaneously, the densely packed HPG brushes generated a maximal steric and hydration barrier that significantly improved biofouling resistance against blood proteins. The optimally functionalized membranes showed a clearance of 83.1% urea and 49.6% lysozyme and a rejection of 96.0% bovine serum albumin. The diversely functionalized PLP-HPG layers demonstrate a potential route for a more integrated hemodialysis membrane that can cope with the urgent issue of hyperhomocysteinemia in clinical hemodialysis therapy.

Amides and Heparin-Like Polymer Co-Functionalized Graphene Oxide Based Core @ Polyethersulfone Based Shell Beads for Bilirubin Adsorption

Excessive bilirubin in the body of patient with liver dysfunction or metabolic obstruction may cause jaundice with irreversible brain damage, and new type of adsorbent for bilirubin is under frequent investigation. Herein, graphene oxide based core @ polyethersulfone-based shell beads are fabricated by phase inversion method, amides and heparin-like polymer are introduced to functionalize the core-shell beads. The beads are successfully prepared with obvious core-shell structure, adequate thermostability and porous shell. Clotting times and protein adsorption are investigated to inspect the hemocompatibility property of the beads. The adsorption of bilirubin is systematically investigated by evaluating the effects of contacting time, initial concentration and temperature on the adsorption, which exhibits improved bilirubin adsorption amount for the beads with amides contained cores or/and shells. It is worth believing that the amides and heparin-like polymer co-functionalized core-shell beads may be utilized in the field of hemoperfusion for bilirubin adsorption.

Interfacial Coating Method for Amine-Rich Surfaces using Poly(ethylene glycol) Diacrylate Applied to Bioprosthetic Valve Tissue Models

Bioprosthetic heart valve implants are beset by calcification and failure due to the interactions between the body and the transplant. Hydrogels can be used as biological blank slates that may help to shield implants from these interactions; however, traditional light-based hydrogel polymerization is impeded by tissue opacity and topography. Therefore, new methods must be created to bind hydrogel to implant tissues. To address these complications, a two-step surface-coating method for bioprosthetic valves was developed. A previously developed bioprosthetic valve model (VM) was used to investigate and optimize the coating method. Generally, this coating is achieved by first reacting surface amine groups with an NHS-PEG-acrylate while also allowing glucose to absorb into the bulk. Then, glucose oxidase, poly(ethylene glycol) diacrylate (PEGDA), and iron ions are added to the system to initiate free-radical polymerization that bonds the PEGDA hydrogel to the acrylates sites on the surface. Results showed a thin (∼8 μm), continuous coating on VM samples that is capable of repelling protein adhesion (2% surface fouling versus 20% on uncoated samples) and does not significantly affect the surface mechanical properties. Based on this success, the coating method was translated to glutaraldehyde-fixed valve tissue samples. Results showed noncontinuous but evident coating on the surface, which was further improved by adjusting the coating solution. These results demonstrate the feasibility of the proposed two-step surface coating method for modifying the surface of bioprosthetic valve replacements.

Graphene-based advanced nanoplatforms and biocomposites from environmentally friendly and biomimetic approaches

Environmentally friendly and biomimetic approaches to fabricate graphene-based advanced nanoplatforms and biocomposites for biomedical applications are summarized in this review.

A substrate-independent ultrathin hydrogel film as an antifouling and antibacterial layer for a microfiltration membrane anchored via a layer-by-layer thiol-ene click reaction

Herein, a substrate-independent ultrathin hydrogel film was constructed on a microfiltration membrane through layer-by-layer (LbL) thiol-ene click chemistry to improve the antifouling and antibacterial properties. In our strategy, ene-functionalized dopamine was synthesized and coated onto a model substrate (polyethersulfone membrane) to introduce double bonds as anchoring sites for the hydrogel film; thiol-functionalized poly[oligo(ethylene glycol)mercaptosuccinate] (POEGMS) and ene-functionalized P(SBMA-co-AA) were synthesized as hydrogel precursors. The membrane was alternately immersed in the precursor solutions to form the ultrathin hydrogel film. Finally, Ag nanoparticles (AgNPs) were loaded into the hydrogel layer by adsorption and reduction procedures. By coating the hydrogel films, the loaded AgNPs could kill almost all the contacting bacteria and the bacteria in the surroundings, and the enhanced hydrophilicity of the modified membrane could effectively prevent the attachment of the bacteria. The membrane flux showed no significant decrease, the rejection ratio of BSA increased from 51% to 89%, and the F_RR increased from 36% to 90%. Moreover, the improvement of the hemocompatibility was confirmed by the decline in the plasma protein adsorption, prolonged clotting times, low hemolysis ratio, and prevention of platelet adhesion. Compared with that of other techniques for attaching hydrogel films, the main advantage of the current technique is that the hydrogel film thickness could be well controlled within the nanometer range; thus, it could significantly improve the antifouling and antibacterial properties of the membrane, but without compromising its permeability. Another advantage is that it is versatile for various substrates such as PVDF, PAN, and CA. This study opens up a facile and versatile route for anchoring ultrathin hydrogel film onto polymeric membranes to achieve excellent antifouling, antibacterial and hemocompatible properties.

A microscopic view of graphene-oxide/poly(acrylic acid) physical hydrogels: effects of polymer charge and graphene oxide loading

In this work we have examined in detail by means of fully atomistic molecular dynamics simulations, physical hydrogels formed by a polymer electrolyte, poly(acrylic acid), and graphene oxide, at two different charging states of the polymer and two different graphene oxide concentrations. It was found that variations of these parameters incurred drastic changes in general morphological characteristics of the composite materials, the degree of physical adsorption of polyelectrolyte chains onto the graphene oxide surface, the polymer dynamic response at local and global length scales, in the charge distributions around the components, and in the mobility of the counterions. All these microscopic features are expected to significantly affect macroscopic physical properties of the hydrogels, such as their mechanical responses and their electrical behaviors.

Mussel-Inspired Synthesis of NIR-Responsive and Biocompatible Ag-Graphene 2D Nanoagents for Versatile Bacterial Disinfections

Pathogenic bacterial infection has been becoming a global threat toward people's health, especially the massive usage of antibiotics due to the lack of antibacterial agents with less side effects. Developing new nanoagents to fight pathogenic bacteria has provided enormous new possibilities in the treatment of bacterial infections, such as graphene-based two-dimensional (2D) antibacterial nanoagents with different bacterial inhibition capabilities; however, mussel-inspired design of near-infrared (NIR)-responsive and biocompatible Ag-graphene nanoagents possessing efficient and versatile bacterial disinfection activities have rarely been reported. In this study, we developed a new kind of antibacterial nanoagent, dopamine-conjugated polysaccharide sulfate-anchored and -protected Ag-graphene (Ag@G-sodium alginate sulfate ((SAS)) nanocomposite, to combat bacterial infection and contamination in different application fields. Ag@G-SAS exhibited robust antibacterial activity toward both Escherichia coli and Staphylococcus aureus; notably, the nanoagent can significantly inhibit S. aureus infection on wounded pig skin without or with NIR laser. Besides wound disinfection, the 2D Ag@G-SAS can also serve as a good layer-by-layer (LbL) building block for the construction of self-sterilizing coatings on biomedical devices. All of the results verified that the LbL-assembled Ag@G-SAS coating exhibited favorable bactericidal activity, extraordinary blood compatibilities, and good promotion ability for cell proliferation. Owing to the shielding effects of heparin-like polysaccharide sulfates, the Ag@G-SAS nanoagent showed limited cytotoxicity toward mammalian cells. Combining all of the advantages mentioned above, it is believed that the proposed Ag@G-SAS nanoagent and its LbL-assembled coatings may have versatile application potentials to avoid bacterial contaminations in different fields, such as wounded skin, disinfection of biomedical implants and devices, and food packaging sterilization.

Design of Antibacterial Poly(ether sulfone) Membranes via Covalently Attaching Hydrogel Thin Layers Loaded with Ag Nanoparticles

To inhibit bacteria attachment and the subsequent formation of biofilms on poly(ether sulfone) (PES) membranes, poly(sulfobetaine methacrylate)/poly(sodium acrylate) antibacterial hydrogel thin layers were covalently attached onto the membranes, followed by loading with Ag nanoparticles. In our strategy, double bonds were firstly introduced onto the PES membrane surfaces to provide anchoring sites, and then the hydrogel layers were synthesized on the membrane surfaces via UV light-initiated crosslinking copolymerization. Then, Ag ions were adsorbed into the hydrogel layers and reduced to Ag nanoparticles by sodium borohydride. The amounts of the adsorbed Ag ions were controlled by the mole ratios of carboxylate groups in the hydrogel layers. After attaching the hydrogel layers, a typical 3D porous structure was observed by scanning electron microscopy, and the surface chemical composition variations were characterized by attenuated total reflection-Fourier transform infrared spectroscopy. The live/dead staining, inhibition zone, and the optical degree of co-culture solution demonstrated that the designed surfaces could not only effectively resist bacteria attachment but also kill the surrounding bacteria Escherichia coli and Staphylococcus aureus. It was noteworthy that the strong antibacterial ability could be maintained for more than 5 weeks. Additionally, the excellent hemocompatibility of the modified membranes was confirmed by undetectable plasma protein adsorption, suppressed platelet adhesion, prolonged clotting time, low hemolysis ratio, and suppressed blood-related complement activation. Cell culture tests indicated that the membranes showed no cytotoxicity, but strong anti-cell adhesion properties. The proposed method to fabricate antibacterial hydrogel thin layers has great potential to be widely used to inhibit the formation of biofilms on various biomedical devices.

Functional Graphene Nanomaterials Based Architectures: Biointeractions, Fabrications, and Emerging Biological Applications

Functional graphene nanomaterials (FGNs) are fast emerging materials with extremely unique physical and chemical properties and physiological ability to interfere and/or interact with bioorganisms; as a result, FGNs present manifold possibilities for diverse biological applications. Beyond their use in drug/gene delivery, phototherapy, and bioimaging, recent studies have revealed that FGNs can significantly promote interfacial biointeractions, in particular, with proteins, mammalian cells/stem cells, and microbials. FGNs can adsorb and concentrate nutrition factors including proteins from physiological media. This accelerates the formation of extracellular matrix, which eventually promotes cell colonization by providing a more beneficial microenvironment for cell adhesion and growth. Furthermore, FGNs can also interact with cocultured cells by physical or chemical stimulation, which significantly mediate their cellular signaling and biological performance. In this review, we elucidate FGNs-bioorganism interactions and summarize recent advancements on designing FGN-based two-dimensional and three-dimensional architectures as multifunctional biological platforms. We have also discussed the representative biological applications regarding these FGN-based bioactive architectures. Furthermore, the future perspectives and emerging challenges will also be highlighted. Due to the lack of comprehensive reviews in this emerging field, this review may catch great interest and inspire many new opportunities across a broad range of disciplines.

Direct catechol conjugation of mussel-inspired biomacromolecule coatings to polymeric membranes with antifouling properties, anticoagulant activity and cytocompatibility

TheO-sulfated chitosan andN,O-sulfated chitosan coatings were prepared by direct catechol conjugation to enrich the biological applications of polymeric membranes.

Comprehensive Review on the Use of Graphene-Based Substrates for Regenerative Medicine and Biomedical Devices

Recent research suggests that graphene holds great potential in the biomedical field because of its extraordinary properties. Whereas initial attempts focused on the use of suspended graphene for drug delivery and bioimaging, more recent work has demonstrated its advantages for preparing substrates for tissue engineering and biomedical devices and products. Cells are known to interact with and respond to nanoparticles differently when presented in the form of a substrate than in the form of a suspension. In tissue engineering, a stable and supportive substrate or scaffold is needed to provide mechanical support, chemical stimuli, and biological signals to cells. This review compiles recent advances of the impact of both graphene and graphene-derived particles to prepare supporting substrates for tissue regeneration and devices as well as the associated cell response to multifunctional graphene substrates. We discuss the interaction of cells with pristine graphene, graphene oxide, functionalized graphene, and hybrid graphene particles in the form of coatings and composites. Such materials show excellent biological outcomes in vitro, in particular, for orthopedic and neural tissue engineering applications. Preliminary evaluation of these graphene-based materials in vivo reinforces their promise for tissue regeneration and implants. Although the reported findings of studies on graphene-based substrates are promising, several questions and concerns associated with their in vivo use persist. Possible strategies to examine these issues are presented.

Diffusion-Weighted Magnetic Resonance Imaging for Therapy Response Monitoring and Early Treatment Prediction of Photothermal Therapy

Photothermal therapy (PTT) as a relatively new cancer treatment method has attracted worldwide attention. Previous research on PTT has focused on its therapy efficiency and selectivity. The early prognosis of PTT, which is pivotal for the assessment of the treatment and the therapy stratification, however, has been rarely studied. In the present study, we investigated diffusion-weighted magnetic resonance imaging (DW-MRI) as a tool for therapy monitoring and early prognosis of PTT. To this end, we injected PEGylated graphene oxide (GO-PEG) or iron oxide deposited graphene oxide (GO-IONP-PEG) to 4T1 tumor models and irradiated the tumors at different drug-light intervals to induce PTT. For GO-IONP-PEG injected animals, we also included therapy arms where an external magnetic field was applied to the tumors to improve the delivery of the nanoparticle transducers. DW-MRI was performed at different time points after PTT and the tumor apparent diffusion coefficients (ADCs) were analyzed and compared. Our studies show that photothermal agents, magnetic guidance, and drug-light intervals can all affect PTT treatment efficacy. Impressively, ADC value changes at early time points after PTT (less than 48 h) were found to be well-correlated with tumor growth suppression that was apparent days or weeks later. The changes were most sensitive to conditions that can extend the survival for more than 4 weeks, in which cases the 48 h ADC values were increased by more than 80%. These studies demonstrate for the first time that DW-MRI can be an accurate prognosis tool for PTT, suggesting an important role it can play in the future PTT evaluation and clinical translation of the modality.

Graphene oxide and sulfonated polyanion co-doped hydrogel films for dual-layered membranes with superior hemocompatibility and antibacterial activity

GO based dual-layered membranes with superior hemocompatibility and antibacterial activity have potential application for clinical hemodialysis and many other biomedical therapies.

Highly hemo-compatible, mechanically strong, and conductive dual cross-linked polymer hydrogels

Novel hydrogels with highly hemo-compatible, mechanically strong and conductive properties are developed as promising candidates for a wide range of biomedical applications.

Highly swellable and biocompatible graphene/heparin-analogue hydrogels for implantable drug and protein delivery

The GO/heparin-analogue hydrogels with hemo- and cyto-compatibility could be used in various biomedical fields, such as drug and protein delivery, tissue regeneration scaffold, and other biomedical systems.

Graphene oxide linked sulfonate-based polyanionic nanogels as biocompatible, robust and versatile modifiers of ultrafiltration membranes

A GO linked sulfonate-based polyanionic nanogel as a membrane modifier has application potential in clinical hemodialysis and other biomedical therapies.

In situ cross-linking of stimuli-responsive hemicellulose microgels during spray drying

Chemical cross-linking during spray drying offers the potential for green fabrication of microgels with a rapid stimuli response and good blood compatibility and provides a platform for stimuli-responsive hemicellulose microgels (SRHMGs). The cross-linking reaction occurs rapidly in situ at elevated temperature during spray drying, enabling the production of microgels in a large scale within a few minutes. The SRHMGs with an average size range of ∼ 1-4 μm contain O-acetyl-galactoglucomannan as a matrix and poly(acrylic acid), aniline pentamer (AP), and iron as functional additives, which are responsive to external changes in pH, electrochemical stimuli, magnetic field, or dual-stimuli. The surface morphologies, chemical compositions, charge, pH, and mechanical properties of these smart microgels were evaluated using scanning electron microscopy, IR, zeta potential measurements, pH evaluation, and quantitative nanomechanical mapping, respectively. Different oxidation states were observed when AP was introduced, as confirmed by UV spectroscopy and cyclic voltammetry. Systematic blood compatibility evaluations revealed that the SRHMGs have good blood compatibility. This bottom-up strategy to synthesize SRHMGs enables a new route to the production of smart microgels for biomedical applications.

Nanofibrous heparin and heparin-mimicking multilayers as highly effective endothelialization and antithrombogenic coatings

Combining the advantages of the fibrous nanostructure of carbon nanotubes (CNTs) and the bioactivities of heparin/heparin-mimicking polyanions, functional nanofibrous heparin or heparin-mimicking multilayers were constructed on PVDF membrane with highly promoted endothelialization and antithrombogenic activities. Oxidized CNT (oCNT) was first functionalized with water-soluble chitosan (polycation), then enwrapped with heparin or a typical sulfonated heparin-mimicking polymers (poly(sodium 4-styrenesulfonate-co-sodium methacrylate)) to construct the multilayers. Then, the surface-deposited multilayers were constructed via electrostatic layer-by-layer assembly of the functionalized oCNTs. The scanning electron microscope and atom force microscope images confirmed that the coated multilayers exhibited nanofibrous and porous structure. The live/dead cell staining and cell viability assay results indicated that the coated nanofibrous multilayers had excellent compatibility with endothelial cells. The cell morphology observation further confirmed the promotion ability of surface endothelialization due to the coated heparin/heparin-mimicking multilayers. Further systematical evaluation on blood compatibility revealed that the surface heparin/heparin-mimicking multilayer-coated membranes also had significantly improved blood compatibility including restrained platelet adhesion and activation, prolonged blood clotting times, and inhibited activation of coagulation and complement factors. In summary, the proposed nanofibrous multilayers integrated endothelialization and antithrombogenic properties; meanwhile, the heparin-mimicking coating validated comparable performances as heparin coating. Herein, it is expected that the surface coating of nanofibrous multilayers, especially the facilely constructed heparin-mimicking coating, may have great application potential in biomedical fields.

Characterization and antifouling properties of polyethylene glycol doped PAN–CAP blend membrane

The effects of polyethylene glycol (PEG) as an additive to a cellulose acetate phthalate–polyacrylonitrile blend membrane in the ultrafiltration range were investigated.

Graphene oxide based heparin-mimicking and hemocompatible polymeric hydrogels for versatile biomedical applications

Inspired from the chemical and biological benefits of heparinized hydrogels, this study presented the substituted hemocompatible design of graphene oxide based heparin-mimicking polymeric hydrogels for versatile biomedical applications.

Robust, highly elastic and bioactive heparin-mimetic hydrogels

We construct robust, highly elastic, and bioactive graphene oxide doped heparin-mimetic hydrogels for use in drug delivery and other potential biomedical applications.

Layer by layer assembly of sulfonic poly(ether sulfone) as heparin-mimicking coatings: scalable fabrication of super-hemocompatible and antibacterial membranes

In this study, super-hemocompatible and antibacterial polymeric membranes with surface coated nanofilms were fabricated by LBL assembly of water-soluble heparin-mimicking polymer and quaternized chitosan.

Biodegradable and conductive chitosan–graphene quantum dot nanocomposite microneedles for delivery of both small and large molecular weight therapeutics

Chitosan–graphene quantum dot nanocomposites are used in microneedle arrays for transdermal delivery of small and large molecular weight drugs.

An introduction to the chemistry of graphene

This perspective outlines the chemistry of graphene, including functionalization, doping, photochemistry, catalytic chemistry and supramolecular chemistry.

One-pot cross-linked copolymerization for the construction of robust antifouling and antibacterial composite membranes

This study reports a highly efficient, convenient and universal protocol for the fabrication of robust antifouling and antibacterial polymeric membranes via one-pot cross-linked copolymerization of functional monomers.

A hierarchical rippled and crumpled PLA microstructure generated through double emulsion: the interesting roles of Pickering nanoparticles

The delicate roles of Pickering nanoparticles for the in situ creation of hierarchical rippled and crumpled textures upon biomedical polymers were uncovered and demonstrated.

Catechol chemistry inspired approach to construct self-cross-linked polymer nanolayers as versatile biointerfaces

In this study, we proposed a catechol chemistry inspired approach to construct surface self-cross-linked polymer nanolayers for the design of versatile biointerfaces. Several representative biofunctional polymers, P(SS-co-AA), P(SBMA-co-AA), P(EGMA-co-AA), P(VP-co-AA), and P(MTAC-co-AA), were first synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization, and then the catecholic molecules (dopamine, DA) were conjugated to the acrylic acid (AA) units by the facile carbodiimide chemistry. Then, the catechol (Cat) group conjugated biofunctional polymers, named PSS-Cat, PSBMA-Cat, PEGMA-Cat, PVP-Cat, and PMTAC-Cat, were applied for the construction of self-cross-linked nanolayers on polymeric substrates via the pH induced catechol cross-linking and immobilization. The XPS spectra, surface morphology, and wettability gave robust evidence that the catechol conjugated polymers were successfully coated, and the coated substrates possessed increased surface roughness and hydrophilicity. Furthermore, the systematic in vitro investigation of protein adsorption, platelet adhesion, activated partial thromboplastin time (APTT), thrombin time (TT), cell viability, and antibacterial ability confirmed that the coated nanolayers conferred the substrates with versatile biological performances. The PSS-Cat coated substrate had low blood component activation and excellent anticoagulant activity; while the PEGMA-Cat and PSBMA-Cat showed ideal resistance to protein fouling and inhibition of platelet activation. The PSS-Cat and PVP-Cat coated substrates exhibited promoted endothelial cell proliferation and viability. The PMTAC-Cat coated substrate showed an outstanding activity on bacterial inhibition. In conclusion, the catechol chemistry inspired approach allows the self-cross-linked nanolayers to be easily immobilized on polymeric substrates with the stable conformation and multiple biofunctionalities. It is expected that this low-cost and facile bioinspired coating system will present great potential in creating novel and versatile biointerfaces.

Heparin-mimicking multilayer coating on polymeric membrane via LbL assembly of cyclodextrin-based supramolecules

In this study, multifunctional and heparin-mimicking star-shaped supramolecules-deposited 3D porous multilayer films with improved biocompatibility were fabricated via a layer-by-layer (LbL) self-assembly method on polymeric membrane substrates. Star-shaped heparin-mimicking polyanions (including poly(styrenesulfonate-co-sodium acrylate; Star-PSS-AANa) and poly(styrenesulfonate-co-poly(ethylene glycol)methyl ether methacrylate; Star-PSS-EGMA)) and polycations (poly(methyl chloride-quaternized 2-(dimethylamino)ethyl methacrylate; Star-PMeDMA) were first synthesized by atom transfer radical polymerization (ATRP) from β-cyclodextrin (β-CD) based cores. Then assembly of 3D porous multilayers onto polymeric membrane surfaces was carried out by alternating deposition of the polyanions and polycations via electrostatic interaction. The surface morphology and composition, water contact angle, blood activation, and thrombotic potential as well as cell viability for the coated heparin-mimicking films were systematically investigated. The results of surface ATR-FTIR spectra and XPS spectra verified successful deposition of the star-shaped supramolecules onto the biomedical membrane surfaces; scanning electron microscopy (SEM) and atomic force microscopy (AFM) observations revealed that the modified substrate had 3D porous surface morphology, which might have a great biological influence on the biointerface. Furthermore, systematic in vitro investigation of protein adsorption, platelet adhesion, human platelet factor 4 (PF4, indicates platelet activation), activate partial thromboplastin time (APTT), thrombin time (TT), coagulation activation (thrombin-antithrombin III complex (TAT, indicates blood coagulant)), and blood-related complement activation (C3a and C5a, indicates inflammation potential) confirmed that the heparin-mimicking multilayer coated membranes exhibited ultralow blood component activations and excellent hemocompatibility. Meanwhile, after surface coating, endothelial cell viability was also promoted, which indicated that the heparin-mimicking multilayer coating might extend the application fields of polymeric membranes in biomedical fields.

Light-Triggered Switching of Reversible and Alterable Biofunctionality via β-Cyclodextrin/Azobenzene-Based Host-Guest Interaction

Most of the recent reports focused on using cyclodextrin/azobenzene/polymer for reversible immobilization of biomolecules, the reversible photoswitching of biofunctions via universal and low-cost strategy, were barely investigated. Herein, we report light-triggered switching of reversible and alterable biofunctionality on silicon interface via β-cyclodextrin/azobenzene based host-guest interaction. Biofunctional azobenzene-grafted polymers were synthesized and assembled onto β-cyclodextrin anchored interfaces to form "smart" monolayers of light-triggered switchable brushes. The photoresponsive interfaces exhibit reversible and alterable biofunctionality switching from antibacterial/hemostatic to bioadhesion/anticoagulant upon ultraviolet and visible (UV-vis) light cycles.

Graphene oxide interpenetrated polymeric composite hydrogels as highly effective adsorbents for water treatment

In this study, synthetic GO interpenetrated PAA composite hydrogels were prepared and systematically studied as 3D high-efficient adsorbents for water treatment.

Surface-engineered nanogel assemblies with integrated blood compatibility, cell proliferation and antibacterial property: towards multifunctional biomedical membranes

This study presents the fabrication of multifunctional nanolayers on biomedical membrane surfaces by using LBL self-assembly of nanogels and heparin-like polymers.

Blood activation and compatibility on single-molecular-layer biointerfaces

Research on the interactions between living systems and materials is fuelled by diverse biomedical needs, for example, drug encapsulation and stimulated release, stem cell proliferation and differentiation, cell and tissue cultures, as well as artificial organs.