Patterning Surfaces for Controlled Platelet Adhesion and Detection of Dysfunctional Platelets

Modulation of Platelet-Surface Activation: Current State and Future Perspectives

Modulation of platelet-surface activation is important for many biomedical applications such as in vivo performance, platelet storage, and acceptance of an implant. Reducing platelet-surface activation is challenging because they become activated immediately after short contact with nonphysiological surfaces. To date, controversies and open questions in the field of platelet-surface activation still remain. Here, we review state-of-the-art approaches in inhibiting platelet-surface activation, mainly focusing on modification, patterning, and methodologies for characterization of the surfaces. As a future perspective, we discuss how the combination of biochemical and physiochemical strategies together with the topographical modulations would assist in the search for an ideal nonthrombogenic surface.

Surface modification of polyisobutylene via grafting amino acid-based poly (acryloyl-6-aminocaproic acid) as multifunctional material

Amino acid-based P(acryloyl-6-aminocaproic acid) (PAACA) brushes were fabricated on polyisobutylene (PIB) surface combined with plasma pre-treatment and UV-induced grafting polymerization to construct an antifouling and functional material. The hydrophilicity and hemocompatibility of PIB were largely improved by surface modification of AACA, which were confirmed by water contact angle and platelet adhesion, respectively. PAACA brushes were precisely located onto the surface of PIB to create a patterned PIB-g-PAACA structure, and then the carboxyl groups on PAACA was activated to immobilize functional protein-Concanavalin A (Con A). The obtained Con A-coupled microdomains could further capture erythrocytes. This method developed a platform on commercial PIB surface via amino acid-based polymer brushes which had a promising application in drug delivery and disease diagnosis.

Preparation of an Arg-Glu-Asp-Val Peptide Density Gradient on Hyaluronic Acid-Coated Poly(ε-caprolactone) Film and Its Influence on the Selective Adhesion and Directional Migration of Endothelial Cells

Selective adhesion and migration of endothelial cells (ECs) over smooth muscle cells (SMCs) is very important in the rapid endothelialization of blood-contacting implants to prevent vascular restenosis. In this study, a uniform cell-resistant layer of methacrylate-functionalized hyaluronic acid (HA) was first immobilized on a poly(ε-caprolactone) (PCL) film via polydopamine coupling. Then, a density gradient of thiol-functionalized Arg-Glu-Asp-Val (REDV) peptide was prepared on the HA layer via thiol-ene click chemistry and the continuous injection method. The REDV gradient selectively enhanced EC adhesion and preferential directional migration toward the region of higher REDV density, reaching 86% directionality in the middle of the gradient. The migration rate of ECs was also significantly enhanced twofold compared with that on tissue culture polystyrene (TCPS). In contrast, the gradient significantly weakened the adhesion of SMCs to 25% of that on TCPS but had no obvious impact on the migration rate and directionality. Successful modulation of the selective adhesion and directional migration of ECs over SMCs on biodegradable polymers serves as an important step toward practical applications for guided tissue regeneration.

A Novel Platelet-Repellent Polyphenolic Surface and Its Micropattern for Platelet Adhesion Detection

Surface patterning provides a powerful tool to the diagnosis of platelet adhesion. However, the current methodologies of constructing platelet-patterned surfaces require laborious and complicated steps. Herein, a novel and simple platelet-repellent surface was reported by metal (Fe³⁺ ions)-polyphenol (tannic acid, TA) coordination interaction. The platelet-repellent effect was significantly better than that of poly(ethylene glycol) (PEG) in a long-term. Moreover, the platelet-repellent behavior could extend to other polyphenols-functionalized surfaces. On the basis of these observations, a TA-based micropattern was fabricated in situ by one-step microcontact printing for well-defined platelet adhesion, which can effectively avoid the traditional introduction of inert hydrophilic polymers and bioactive ligands. Afterward, the TA-based micropattern was applied to monitor the adhesion of defective platelets treated with an antiplatelet drug (tirofiban). This work provided a facile, versatile, and environmentally friendly strategy to construct platelet-repellent polyphenolic surfaces and their micropattern. We expect that this simple micropattern could act as a low-cost and label-free platform for biomaterials and biosensors, and could be widely used in the clinical diagnoses of platelet adhesive functions and the evaluation of antiplatelet therapies.

Capturing red blood cells from the blood by lectin recognition on a glycopolymer-patterned surface

A glycopolymer-patterned surface selectively captures red blood cells from the blood by lectin recognition in a harmless manner.

Construction of d-α-tocopheryl polyethylene glycol succinate/PEO core–shell nanofibers on a blood-contacting surface to reduce the hemolysis of preserved erythrocytes

The TPGS released from the electrospun SEBS protected the preserved red blood cells from oxidative damage, resulting in low hemolysis and mechanical fragility.

A novel hydrophilic polymer-brush pattern for site-specific capture of blood cells from whole blood

A novel hydrophilic PAMPS–PAAm brush pattern is fabricated to selectively capture blood cells from whole blood.

Biomimetic honeycomb-patterned surface as the tunable cell adhesion scaffold

PS honeycomb structured surfaces were modified into both cell-philic and cell-phobic by dip-coating and casting polySBMA, respectively, which was inspired by two typically adhesive behaviours of fish skin and Parthenocissus tricuspidata.

Construction of 3D micropatterned surfaces with wormlike and superhydrophilic PEG brushes to detect dysfunctional cells

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.

Controlled lecithin release from a hierarchical architecture on blood-contacting surface to reduce hemolysis of stored red blood cells

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.

Superhydrophobic coating of elastomer on different substrates using a liquid template to construct a biocompatible and antibacterial surface

Elastomers were cast with a liquid template to create superhydrophobic, biocompatible, antifouling and antibacterial surfaces on virtually any substrate.

Precise patterning of the SEBS surface by UV lithography to evaluate the platelet function through single platelet adhesion

The micropatterned surface which was createdviaUV lithography with a photomask, was demonstrated to control single platelet adhesion, render platelets sensitive to proteins and enable assessment of the platelet function in the presence of antiplatelet agents through single platelet adhesion.