Expanded nanofibrous polymeric dressings containing tetracycline-loaded nanoparticles for wound healing

C. BUSATTO; S. BONGIOVANNI; F. FOOKES; D. ESTENOZ; GUSTAVO ABRAHAM

Congreso; XII Congreso Latinoamericano de Órganos Artificiales y Biomateriales; 2023

The treatment of skin lesions requires the application of temporary barriers that protect the wound from harmful agents and improve the healing process. Electrospun polymeric nanofibers have shown great potential as wound healing dressings because they can mimic the extracellular environment of tissues [1]. In addition, therapeutic and antibacterial agents can be easily incorporated during the electrospinning process to obtain multifunctional materials.The aim of this work is to study novel nanofibrous polymeric dressings with an expanded structure in combination with mesoporous silica nanoparticles (MSN) as carriers of tetracycline for their potential application in skin tissue engineering. MSN were synthesized by the sol-gel process [2]. The morphology, particle size and the specific surface area of MSN were determined by SEM, TEM and BET analysis. Tetracycline was loaded into MSN by immersion of MSN in a concentrated drug solution. The drug content was determined by TGA analysis and UV-Vis spectroscopy.The experimental conditions for the electrospinning of PVA solutions were optimized, and MSN were incorporated in variable concentrations. The electrospun matrices were placed in an ethanol solution of NaBH4 for the expansion procedure. The nanocomposite materials were characterized in terms of their physicochemical, superficial, thermal and morphological properties.The average size of MSN was 304 ± 35 nm and TEM micrographs showed a highly ordered periodic porous microstructure. The nanoparticles show a Type IV BET adsorption isotherm, typically for samples with mesoporosity. The TGA analysis showed that silica nanoparticles exhibited excellent thermal stability and the TGA profile of tetracycline-loaded MSN mimicked the one of tetracycline, albeit with a much lower percentage of weight loss. Tetracycline loading into the MSN was calculated to be around 9% (w/w). The tetracycline release profiles from MSN showed a sustained release for about 15 h.Homogeneous fiber mats with randomly orientated and defect-free fibers were obtained for the hybrid scaffolds. A thermal crosslinking process was performed to avoid the dissolution of PVA fibers in aqueous media. The SEM micrographs reveal a homogeneous distribution of MSN in the fibrous mats with a mean fiber diameter of 202 ± 60 and 185 ± 42 nm for PVA and PVA-MSN (3 wt.%), respectively. In addition, the thermal properties of the mats were improved with the MSN content. The expanded materials exhibited an increase in the dressing’s thickness due to the larger size and interconnection between the pores of the matrix.Tetracycline was loaded into MSN at a considerably high load and electrospun PVA fibers containing MSN were fabricated with different nanoparticle contents. Nanoparticles were homogeneously embedded in the polymeric matrix along the composite fibers. The nanofibrous polymeric dressings were crosslinked and expanded in order to improve their mechanical properties and increase their pore size and interconnection. In future works, the antimicrobial properties of the expanded nanofibrous materials will be evaluated.