Zwitterionic-Based Surface via the Coelectrodeposition of Colloid Particles and Tannic Acid with Bacterial Resistance but Cell Adhesion Properties

Facile fabrication of biodegradable endothelium-mimicking coatings on bioabsorbable zinc-alloy stents by one-step electrophoretic deposition

The zinc-alloy stent is one of the best potential candidates for bioabsorbable metal stents because of its appropriate corrosion rate aligned to the duration of the healing process of the surrounding vessel tissues. However, excessive release of zinc ions, causing cytotoxicity of endothelial cells, and insufficient surface bio-functions of Zn-alloy stents lead to considerable challenge in their application. Herein, one-step electrophoretic deposition was employed to apply a hybrid coating of polycarbonate, tannic acid, and copper ions with tailored functions on Zn-alloy stents to enhance their corrosion resistance and provide an endothelium-mimicking surface. Specifically, the synthesized amino-functionalized aliphatic polycarbonates endowed the hybrid coating with specific surface-erosion properties, resulting in superior corrosion resistance and long-term stability in degradation tests both in vitro and in vivo. The immobilized copper ions enabled the catalytic generation of nitric oxide and promoted the adhesion and proliferation of endothelial cells on zinc alloy. The added tannic acid firmly chelated the copper ions and formed durable phenolic-copper-amine crosslinked networks by electrostatic interaction, resulting in long-term stability of the hybrid coating during the 21 day dynamic immersion test. Tannic acid exerted a synergistic antibacterial effect with copper ions as well as a reduction in the inflammatory response to the zinc substrate. In addition, the hybrid coating improved the in vitro hemocompatibility of zinc alloys. By adjusting the amount of chelated copper in the coating system, the biological function of the corresponding coatings can be controlled, providing a facile surface treatment strategy to promote the progress of zinc-alloy stents in clinical applications.

Recent progress in Tannic Acid-driven antimicrobial/antifouling surface coating strategies

Medical devices and surgical implants are a necessary part of tissue engineering and regenerative medicines. However, the biofouling and microbial colonization on the implant surface continues to be a major...

Surface modification strategies to improve titanium hemocompatibility: a comprehensive review

Titanium and its alloys are widely used in different biomaterial applications due to their remarkable mechanical properties and bio-inertness. However, titanium-based materials still face some challenges, with an emphasis on hemocompatibility. Blood-contacting devices such as stents, heart valves, and circulatory devices are prone to thrombus formation, restenosis, and inflammation due to inappropriate blood-implant surface interactions. After implantation, when blood encounters these implant surfaces, a series of reactions takes place, such as protein adsorption, platelet adhesion and activation, and white blood cell complex formation as a defense mechanism. Currently, patients are prescribed anticoagulant drugs to prevent blood clotting, but these drugs can weaken their immune system and cause profound bleeding during injury. Extensive research has been done to modify the surface properties of titanium to enhance its hemocompatibility. Results have shown that the modification of surface morphology, roughness, and chemistry has been effective in reducing thrombus formation. The main focus of this review is to analyze and understand the different modification techniques on titanium-based surfaces to enhance hemocompatibility and, consequently, recognize the unresolved challenges and propose scopes for future research.

Thermally Stable Bioinert Zwitterionic Sulfobetaine Interfaces Tolerated in the Medical Sterilization Process

This work introduces a thermally stable zwitterionic structure able to withstand steam sterilization as a general antifouling medical device interface. The sulfobetaine methacrylate (SBMA) monomer and its polymer form are among the most widely used zwitterionic materials. They are easy to synthesize and have good antifouling properties. However, they partially lose their properties after steam sterilization, a common procedure used to sterilize biomedical interfaces. In this study, ultrahigh-performance liquid chromatography/mass spectrometry (UHPLC-MS) was used to analyze and discuss the molecular structure of SBMA before and after a steam sterilization procedure, and a strategy to address the thermal stability issue proposed, using sulfobetaine methacrylamide (SBAA) instead of SBMA. Interestingly, it was found that the chemical structure of SBAA material can withstand the medical sterilization process at 121 °C while maintaining good antifouling properties, tested with proteins (fibrinogen), bacteria (Escherichia coli), and whole blood. On the other hand, SBMA gels failed at maintaining their excellent antifouling properties after sterilization. This study suggests that the SBAA structure can be used to replace SBMA in the bioinert interface of sterilizable medical devices, such as rayon fiber membranes used for disease control.

Development of superhydrophillic tannic acid-crosslinked graphene oxide membranes for efficient treatment of oil contaminated water with enhanced stability

In the present age of industrialization, oil contamination in the waste water has become a huge global concern due to its several negative impacts on human health and aquatic ecosystem. In order to address this problem, a novel oleophobic and super-hydrophilic graphene-based membrane has been developed using simple and cost-effective vacuum filtration methodology. Prior developing the membranes, the graphene oxide (GO) sheets were crosslinked with tannic acid (TA) molecules in order to improve their mechanical and surface properties. To obtain the structural and morphological information of the membranes and their constituents, Field Emission Scanning Electron (FE-SEM) microscopy, X-Ray Diffraction (XRD), FTIR spectroscopy and Raman spectroscopy was used. When tested with simulated oilfield effluent samples, these membranes exhibited significant reduction in the values of chemical oxygen demand (COD), total dissolved solids (TDS), total suspended solids (TSS) and turbidity demonstrating low-oil adhesion and preferable oil rejection rates. Moreover, such crosslinked membranes are highly stable which can withstand the pressure of water filtration. In such a way, TA crosslinked GO membranes present a robust and efficient way to treat oil contaminated water released from various industries which can be reused for numerous further applications.

Monoterpenes and Their Derivatives-Recent Development in Biological and Medical Applications

Monoterpenes, comprising hydrocarbons, are the largest class of plant secondary metabolites and are commonly found in essential oils. Monoterpenes and their derivatives are key ingredients in the design and production of new biologically active compounds. This review focuses on selected aliphatic, monocyclic, and bicyclic monoterpenes like geraniol, thymol, myrtenal, pinene, camphor, borneol, and their modified structures. The compounds in question play a pivotal role in biological and medical applications. The review also discusses anti-inflammatory, antimicrobial, anticonvulsant, analgesic, antiviral, anticancer, antituberculosis, and antioxidant biological activities exhibited by monoterpenes and their derivatives. Particular attention is paid to the link between biological activity and the effect of structural modification of monoterpenes and monoterpenoids, as well as the introduction of various functionalized moieties into the molecules in question.

Zwitterionic Polymer-Grafted Polylactic Acid Vascular Patches Based on a Decellularized Scaffold for Tissue Engineering

More than 10 million people suffer from cardiovascular diseases, and diseased blood vessels need to be treated with vascular patches. For a vascular patch, good affinity for endothelial progenitor cells is a key factor in promoting the formation of endothelial tissue-endothelialization. To construct such a vascular patch with good cell affnity, in this work, we first synthesized a reactive zwitterionic organophosphate containing a phosphorylcholine headgroup: 6-(acryloyloxy)hexyl-2-(N-isopropyl-N,N-dimethylammonio)ethyl phosphate (AHEP). We then grafted AHEP onto a polylactic acid (PLA)-coated decellularized scaffold to obtain a vascular patch. Its hydrophilicity and biocompatibility were investigated. Its in vivo performance was also examined in a pig model with B-ultrasonography, Doppler spectra, and computed tomography angiography. The vascular patch demonstrated a nonhemolytic property, noncytotoxicity, long in vitro coagulation times, the strong ability to resist platelet adhesion, and a good affinity for endothelial progenitor cells. The vascular patch was able to maintain the long-term patency (5 months) of surgical arteries. Hence, the zwitterionic polymer-grafted PLA vascular patch may be a promising candidate for vascular tissue engineering.