Preparation and characterization of a biocompatible glucose-sensitive electrospun nanofibers scaffolds containing dexamethasone with enhanced osteogenic propertiesin vitrohigh glucose environment.

Diabetes has made it challenging to repair alveolar bone defects. A successful method for bone repair utilizes a glucose-sensitive osteogenic drug delivery. This study created a new glucose-sensitive nanofiber scaffold with controlled dexamethasone (DEX) release. DEX-loaded polycaprolactone/chitosan nanofibers scaffolds were created using electrospinning. The nanofibers had high porosity (>90%) and proper drug loading efficiency (85.51 ± 1.21%). Then, glucose oxidase (GOD) was immobilized on the obtained scaffolds by a natural biological cross-linking agent, genipin (GnP), after soaking in the mixture solution containing GOD and GnP. The enzyme properties and glucose sensitivity of the nanofibers were investigated. The results showed that GOD was immobilized on the nanofibers and exhibited good enzyme activity and stability. Meanwhile, the nanofibers expanded gradually in response to the increase in glucose concentration, followed by the release of DEX increased. The phenomena indicated that the nanofibers could sense glucose fluctuation and possess favorable glucose sensitivity. In addition, the GnP nanofibers group showed lower cytotoxicity in the biocompatibility test compared with a traditional chemical cross-linking agent. Lastly, the associated osteogenesis evaluation found that the scaffolds effectively promoted MC3T3-E1 cells' osteogenic differentiation in high-glucose environments. As a result, the glucose-sensitive nanofibers scaffolds offer a viable treatment option for people with diabetes with alveolar bone defects.

Glucose-sensitive delivery of tannic acid by a photo-crosslinked chitosan hydrogel film for antibacterial and anti-inflammatory therapy.

A glucose-sensitive antibacterial and anti-inflammatory hydrogel film with controlled release of tannic acid (TA) was synthesized using chitosan (CS). Specifically, the photo-crosslinked CS hydrogel was first obtained and then immersed in TA solution to generate composite hydrogel film with enhanced mechanical properties. Subsequently, N-hydroxysuccinimide/1-ethyl-3-(3-dimethylaminopropyl) carbodiimide based coupling chemistry was used to covalently crosslink glucose oxidase (GOx) to CS to obtain glucose sensitivity. The physicochemical properties, including chemical composition, enzyme-related characteristics, glucose responsiveness, and mechanical strength, were thoroughly investigated, followed by the cytotoxicity, antibacterial and anti-inflammatory tests. The results showed that the GOx immobilized on the film surface by covalent bonding gave better stability than those that were physically adsorbed. In addition, it could quickly and correspondingly modify its inner pore structure in response to the glucose stimulus and then control the loaded TA release. Meanwhile, the TA addition could enhance the film's mechanical properties. The composite hydrogel film demonstrated adequate biocompatibility and can inhibit NO, IL-6, and TNF-α production in stimulated macrophages, as well as Porphyromonas gingivalis growth, demonstrating effective antibacterial and anti-inflammatory activity.