Modified Sol–Gel Synthesis of Mesoporous Borate Bioactive Glasses for Potential Use in Wound Healing

Abstract

In this study, we successfully utilized nitrate precursors for the synthesis of silver (Ag)-doped borate-based mesoporous bioactive glass (MBGs) based on the 1393B3 glass formulation in the presence of a polymeric substrate (polyvinyl alcohol (PVA)) as a stabilizer of boric acid. The X-ray diffraction (XRD) analysis confirmed the glassy state of all the MBGs. The incorporation of 7.5 mol% Ag into the glass composition led to a decrease in the glass transition temperature (Tg). Improvements in the particle size, zeta potential, surface roughness, and surface area values were observed in the Ag-doped MBGs. The MBGs (1 mg/mL) had no adverse effect on the viability of fibroblasts. In addition, Ag-doped MBGs exhibited potent antibacterial activity against gram-positive and gram-negative species. In summary, a modified sol–gel method was confirmed for producing the Ag-doped 1393B3 glasses, and the primary in vitro outcomes hold promise for conducting in vivo studies for managing burns.

Zinc- and Copper-Doped Mesoporous Borate Bioactive Glasses: Promising Additives for Potential Use in Skin Wound Healing Applications

“…The reason behind this observation was attributed to the formation of highly crystalline HAp onto the MBGs (HAp is formed in alkaline pH, and its formation decreases the pH) [ 39 , 40 ]. Furthermore, the re-entering of the doped ions into the structure of newly mineralized HAp could reduce their concentrations in SBF, as also reported previously [ 16 ]. As displayed in Figure 9 , Figure 10 and Figure 11 , the Cu-doped MBGs were more active than their Zn-doped counterparts as regards their behaviors in the biological solutions (faster/higher pH changes and higher ion release).…”

“…This data clustering was in line with previous reports [ 31 , 32 ], which indicated the role of dopants on the particle size, surface charge, and surface area of the MBGs. Based on the obtained results, adding and increasing the concentration of the dopants led to the following: (I) a decrease in the particle size (from 378 to 64 nm), due to the role of the dopants in the prevention of particle growth and agglomeration; (II) decrease in the zeta potential value (from −12 to −26 mV), as a result of the gradient distribution of dopants from bulk to the surface, as also observed in [ 16 , 33 ]; (III) and enhancement of the S BET (from 54 to 131 m 2 /g), because of the important role of dopants on particle size of MBGs (the lower the particle size, the higher the S BET ). For clarification of the mentioned results, we used TEM analysis.…”

“…A minor shift of the diffraction peak, corresponding to the (211) plane of Hap, and an increase of lattice constants of Hap, were observed with increasing of the dopant concentration ( Table 2 ). This observation might be associated with the doping process of Zn 2+ , Cu 2+ , and B 3+ ions into the HAp structure during the adsorption/desorption process of ions in SBF, as reported elsewhere [ 16 ]. Changes in the dynamic surface tension (SFT) of SBF-immersed glasses, including Zn-doped ( Figure 6 ), Cu-doped ( Figure 7 ), and Zn/Cu-doped MBGs ( Figure 8 ), were evaluated for up to 21 days.…”

“…Traditionally, borate BGs are synthesized using the melt-quenching method, due to the inherent easiness of the process, but, on the other hand, the process needs specific equipment, such as high-temperature furnaces. Accordingly, the sol–gel method was gradually applied for the production of borate glasses with specific features, such as a porous texture, that makes them suitable candidates for drug delivery strategies [ 16 , 17 , 18 ]. However, expensive reagents (i.e., methoxy precursors) are generally required for producing sol–gel-derived borate glasses.…”

“…However, expensive reagents (i.e., methoxy precursors) are generally required for producing sol–gel-derived borate glasses. On this matter, Kermani et al successfully developed a modified sol–gel synthesis method for obtaining borate-based MBGs with a high cost–benefit ratio, in which a polymeric substrate (polyvinyl alcohol (PVA)) was used to stabilize boric acid in the reaction and to prepare nano-sized glass particles with a porous texture [ 16 ].…”