Microengineered Multicomponent Hydrogel Fibers: Combining Polyelectrolyte Complexation and Microfluidics

Fiber-based techniques hold great potential toward the development of structures that mimic the architecture of fibrous tissues, such as tendon. Microfluidics and polyelectrolyte complexation are among the most widely used techniques for the fabrication of fibrous structures. In this work, we combined both techniques to generate hydrogel fibers with a fibrillar-like structure. For this, either methacrylated hyaluronic acid (MA-HA) or chondroitin sulfate (MA-CS) were mixed with alginate (ALG), being all negatively charged polysaccharides, combined with chitosan (CHT), which is positively charged, and separately injected into a microfluidic device. Through a continuous injection into a coagulation bath and subsequent photo-cross-linking, we could obtain multicomponent hydrogel fibers, which exhibited smaller fibrils aligned in parallel, whenever CHT was present. The biological performance was assessed upon encapsulation and further culture of tendon cells. Overall, the reported process did not affect cell viability and cells were also able to maintain their main function of producing extracellular matrix up to 21 days in culture. In summary, we developed a novel class of photo-cross-linkable multicomponent hydrogel fibers than can act as bioactive modulators of cell behavior

Pharmaceutical Formulations Containing Graphene and 5‑Fluorouracil for Light-Emitting Diode-Based Photochemotherapy of Skin Cancer

Nonmelanoma skin cancer (NMSC) is the most common cancer worldwide, among which 80% is basal cell carcinoma (BCC). Current therapies’ low efficacy, side effects, and high recurrence highlight the need for alternative treatments. In this work, a partially reduced nanographene oxide (p-rGOn) developed in our laboratory was used. It has been achieved through a controlled reduction of nanographene oxide via UV–C irradiation that yields small nanometric particles (below 200 nm) that preserve the original water stability while acquiring high light-to-heat conversion efficiency. The latter is explained by a loss of carbon–oxygen single bonds (C–O) and the re-establishment of sp2 carbon bonds. p-rGOn was incorporated into a Carbopol hydrogel together with the anticancer drug 5-fluorouracil (5-FU) to evaluate a possible combined PTT and chemotherapeutic effect. Carbopol/p-rGOn/5-FU hydrogels were considered noncytotoxic toward normal skin cells (HFF-1). However, when A-431 skin cancer cells were exposed to NIR irradiation for 30 min in the presence of Carbopol/p-rGOn/5-FU hydrogels, almost complete eradication was achieved after 72 h, with a 90% reduction in cell number and 80% cell death of the remaining cells after a single treatment. NIR irradiation was performed with a light-emitting diode (LED) system, developed in our laboratory, which allows adjustment of applied light doses to achieve a safe and selective treatment, instead of the standard laser systems that are associated with damages in the healthy tissues in the tumor surroundings. Those are the first graphene-based materials containing pharmaceutical formulations developed for BCC phototherapy