Investigating the use of curcumin-loaded electrospun filaments for soft tissue repair applications

Electrospun filaments represent a new generation of medical textiles with promising applications in soft tissue repair. A potential strategy to improve their design is to combine them with bioactive molecules. Curcumin, a natural compound found in turmeric, is particularly attractive for its antioxidant, anti-inflammatory and antimicrobial properties. However, investigating the range of relevant doses of curcumin in materials designed for tissue regeneration has remained limited. In this paper, we explore a wide range of curcumin concentrations and assess the potential of the resulting materials for soft tissue repair applications. Polydioxanone (PDO) filaments were prepared with various amounts of curcumin: 0%, 0.001%, 0.01%, 0.1%, 1% and 10% (w/w ratio). Our results show that, at low doses (≤ 0.1%), the addition of curcumin has no influence on the spinning process or on the physicochemical properties of the filaments, while higher doses lead to smaller fibre diameters and improved mechanical properties. Moreover, filaments with 0.001% and 0.01% curcumin stimulate the metabolic activity and proliferation of normal human dermal fibroblasts (NHDFs) compared to the no-filament control. However, this stimulation is not significant when compared to the control filaments (0%). Highly dosed filaments induce either inhibition of proliferation (with 1%) or cell apoptosis (with 10%) as a result of the concentrations of curcumin found in the medium (9 µM and 32 µM, respectively), which are near or above the known toxicity threshold of curcumin (around 10 µM). Moreover, filaments with 10% curcumin increase the catalase activity and GSH content in NHFDs, indicating an increased production of ROS resulting from the large concentration of curcumin. Overall, this study suggests that PDO electrospun filaments loaded with low amounts of curcumin are more promising than higher concentrations for stimulating tissue repair. It also highlights the need to explore lower concentrations when using polymers similar to PDO, such as with polycaprolactone and other degradable polyesters