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Drug-coated balloon (DCB) is a therapeutic method that can effectively deliver antiproliferative drugs such as paclitaxel and rapamycin (RAPA) with no permanent implants left behind. However, delayed reendothelialization due to the toxicity of the delivered drugs leads to poor therapeutic effects. Here, we propose a new design of DCB coating, which incorporates both vascular endothelial growth factor (VEGF)-encoding plasmid DNA (pDNA) that can promote endothelial repair and RAPA into protamine sulfate (PrS). We demonstrate that the PrS/pDNA/RAPA coating had stability and good anticoagulation properties in vitro. We further show that the coating exhibited excellent transfer capacity from balloon substrates to vessel walls both in vitro and in vivo. Furthermore, the PrS/pDNA/RAPA coating effectively inhibited neointimal hyperplasia after balloon-induced vascular injuries through the down-regulation of the mammalian target of Rapamycin (mTOR) and promoted endothelium regeneration through increased expression of VEGF in vivo. These data indicate that our nanocomposite coating has great potential for use as a novel coating of DCB to treat neointimal hyperplasia after vascular injuries. [ABSTRACT FROM AUTHOR]

Medical devices are becoming more and more significant in our daily life. For implantable medical devices, good biocompatibility is required for further use in vivo. Thus, surface modification of medical devices is really important, which gives a wide application scene for a silane coupling agent. The silane coupling agent is able to form a durable bond between organic and inorganic materials. The dehydration process provides linking sites to achieve condensation of two hydroxyl groups. The forming covalent bond brings excellent mechanical properties among different surfaces. Indeed, the silane coupling agent is a popular component in surface modification. Metals, proteins, and hydrogels are using silane coupling agent to link parts commonly. The mild reaction environment also brings advantages for the spread of the silane coupling agent. In this review, we summarize two main methods of using the silane coupling agent. One is acting as a crosslinker mixed in the whole system, and the other is to provide a bridge between different surfaces. Moreover, we introduce their applications in biomedical devices. [ABSTRACT FROM AUTHOR]

The development of broad-spectrum anti-bacterial tough hydrogels without antibiotics remains a challenge in biomedical applications. In this study, we have synthesized a novel tough anti-bacterial complex hydrogel based on Cu2+ coordination. A swollen and weak poly(acrylamide-co-4-vinylbenzyl-(trihydroxymethyl-phosphonium)chloride) (P(AAm-co-VBzTHPC)) hydrogel was prepared by the radical copolymerization of AAm and VBzTHPC monomer solutions, followed by immersion in CuSO4 solution to coordinate with Cu2+ to form a strong and tough hydrogel. Fourier transform infrared (FTIR) spectra and X-ray photoelectron spectra (XPS) were used to characterize the coordination structure between phosphorus and oxygen atoms in the VBzTHPC monomer and copper ions. The water content and mechanical properties of the obtained hydrogel varied with gel composition. The prepared toughened hydrogel exhibited excellent anti-bacterial performance because of the introduction of copper ion coordination and the slow release of copper ions, with bacterial viability of 5.1% when the mole fraction of VBzTHPC was 10 mol%. Cell viability when cocultured with the toughened hydrogel was above 85% using the Cell Counting Kit-8 (CCK-8) method, indicating the good biocompatibility of the hydrogel. Compared with the control group experiment in vivo, this tough hydrogel can also promote wound healing, making it a promising candidate for wound dressing. [ABSTRACT FROM AUTHOR]