Electrospun silver nanoparticles/curcumin-loaded nanohybrids for Photodynamic Therapy

Chronic wounds are considered a worldwide public health problem, affecting millions yearly. The application of nanofibers associated with drugs and photopharmaceuticals is a promising alternative to meet the clinical needs of sterilization and tissue repair. Thus, aiming at the development of a smart dressing to improve the treatment and healing of these wounds, in the present work, the production of nanofibers containing the mixture of polymers F-127 and PCL with silver nanoparticles (AgNPs) and curcumin (CUR) was proposed and successfully performed, through a design of a photoactive nanoscaffold. A careful study on the optimization of conductivity and viscosity parameters of complex electrospinning nanosuspensions was carried out to obtain homogeneous nanofibrous (NM) matrices with controlled size also incorporated with photodrugs. Several analysis techniques were employed such as Scanning and Transmission Electron Microscopy, indicating diameters of approximately 900 nm and providing images of the AgNPs formed and distributed along the nanofibers with diameters around 12 ± 4 nm. Micro-Raman demonstrates the presence of the SERS effect, also evidencing the interaction of photodrug CUR with AgNPs within the nanofibers. Thermogravimetric analyses indicate the samples’ thermal stability. In addition to the contact angle measurements, proved the hydrophilization of the nanofibers with angle zero, and mechanical properties indicate the elasticity suitable for topical application. Furthermore, swelling studies were performed in simulated wound fluid (FSF), which quantification of CUR incorporated in NM was performed. Subsequently, the in vitro drug release in FSF was also studied, as well as their release kinetics, to evaluate the release of CUR from the nanofiber and determine its first-order kinetics process. The experiment involving photoacoustic spectroscopy was also carried out, evaluating the permeation of drugs in human biomimetic skin system from pig ears, therefor corroborating the results obtained in the in vitro drug release studies, in which CUR delivery from the NM and assisted in permeation is majority modulated by the AgNPs. Finally, the Candida albicans inhibition study showed that the nanosuspensions used in electrospinning as well as the NM were effective in controlling fungal growth, with emphasis on the nanofiber with the AgNPs/CUR combination at pH 8, considered wound pH.