Boronate sol–gel method for one-step fabrication of polyvinyl alcohol hydrogel coatings by simple cast- and dip-coating techniques

Abstract

The self-assembly of polyvinyl alcohol (PVA) and benzene-1,4-diboronic acid (DBA) is employed as a solgel method for one-step fabrication of hydrogel coatings with versatile functionalities. A mixture of PVA and DBA in aqueous ethanol is prepared as a coating agent. The long pot life of the mixture allows for the coating of a wide range of materials with hydrogel films by simple cast-and dip-coating techniques. The resultant films show negligible dissolution in water and the intrinsic hydrophilicity of PVA provides the films with functional properties, such as improved antifogging property and resistance to protein and cell fouling. The self-assembling process shows adaptive inclusion properties toward nanoscale materials, such as metal-organic coordination polymers and inorganic nanoparticles, affording composite films.Furthermore, the coating film exhibits a unique secondary functionalization reactivity toward boronic acid-appended fluorescent dyes, through which a variety of materials are converted into fluorescent materials.

In Situ-Forming Protein-Polymer Hydrogel for Glucose-Responsive Insulin Release

“…They are often considered for smart drug delivery applications. − For instance, dynamic covalent phenylboronic acid (PBA)–diol ester bond-based HGs have demonstrated glucose-responsive behavior and promise to be smart insulin delivery systems for maintaining blood glucose levels in insulin-dependent diabetes patients. − PBA–diol ester bonds are susceptible to break in the presence of d -glucose, the most abundant carbohydrate in the human body. The advantages of using PBA-based glucose-responsive HGs are their chemical stability and minimum toxicity, which enables long-term use in preclinical studies. , In current practice, PBA-containing synthetic polymers are derived from radical polymerization reactions. − Therefore, these materials are exclusively used for external use as catheters and microneedle patches due to their nonbiodegradability. ,− Recently, diol-containing synthetic polymers, such as polyvinyl alcohol (PVA), are crosslinked with bis-PBA-based molecules to produce injectable glucose-responsive insulin-releasing HGs. − Noticeably, for most glucose-responsive HGs, the correlation between bulk rheological properties and glucose-responsive insulin release profile remains elusive. Further, the use of biomacromolecules in the HG composition is desired to improve biocompatibility, biodegradability, and, most importantly, sustainability for future biomedical applications .…”

Glucose-Responsive Chitosan Nanoparticle/Poly(vinyl alcohol) Hydrogels for Sustained Insulin Release In Vivo

“…Therefore, PBA and its derivatives are regularly employed in glucose sensors. − Bulk and nanosized HGs cross-linked with boronate ester bonds have been developed for glucose-responsive drug delivery applications. PBA-functionalized synthetic polymers have been predominately used to realize glucose-responsive insulin delivery in vitro and in vivo . − There are few reports of using biocompatible poly­(vinyl alcohol) (PVA) cross-linked with benzene diboronic acids. − However, the fabrication of such materials requires rigorous synthesis, and the materials suffer from non-biodegradability issues. Therefore, these materials are amenable to external use, such as catheters and microneedles.…”

“…PVA, a hydrophilic polymer, is widely used in HG structures for biomedical applications due to its remarkable biocompatibility and vascular grafting capabilities. Recently, by cross-linking PVA with bis-boronic acids, glucose-responsive HGs for macromolecular drug releases have been developed. − , A CPHG network was formed by the imine bond (between the aldehyde group of cross-linkers and the pendant amine group of CNPs) and boronate ester bond (between boronic acid with the 1,3-diol moiety of PVA) as shown in Figure a. We are inspired by several HG systems that employ imine and boronate ester-based cross-links in their network. ,, These FPBA cross-links show significant binding affinity to saccharides under various pH conditions, leading to glucose-responsive characteristics .…”

Repurposing pinacol esters of boronic acids for tuning viscoelastic properties of glucose-responsive polymer hydrogels: effects on insulin release kinetics

“…Recently, glucose-responsive HGs with poly(vinyl alcohol) (PVA) crosslinked with bis-boronic acid crosslinkers have been developed. 42,43 This strategy offers a relatively straightforward crosslinking of a biocompatible polymer, PVA, with crosslinkers containing two boronic acid moieties. Nonetheless, the insulin release properties of all these hydrogels are not predictable.…”