Abstract (english) | Physico-chemical characterisation: DSC, FTIR, Mechanical testing, SEM - PDO filaments loaded with amounts of curcumin ranging from 0.001% to 10% were successfully prepared by electrospinning. Results indicated that at low doses (≤ 0.1%), the addition of curcumin had no influence on the spinning process or on the mechanics properties of the filaments, while higher doses (≥ 1%) led to smaller fibre diameters and improved strengths and stains. In terms of chemistry (FTIR), the effect of adding curcumin in the PDO matrix was mostly seen in the region 1500-1600 cm-1 but this was difficult to detect below 10%. The thermal properties of the samples (DSC analysis) indicated that the polymer matrix in samples containing 10% of curcumin (C10) was more amorphous than in the others, as reflected by the crystallinity value of around 26% for C10 compared to 40% for the others. Physico-chemical characterisation: Release study - The amounts of curcumin released in culture medium from the different filaments were measured by LC-MS after a period of incubation of 24h. Results indicated that while C0.001 led to concentrations below the limit of detection (0.005μM), C0.01 and C0.1 released curcumin at concentrations around 0.01 μM and 0.1 μM, respectively. Interestingly, C1 released curcumin at around 9 μM and C10 led to concentrations of around 32 μM. Biological characterisation: BrdU, MTT - NHDFs were incubated with the filaments and the effect of released curcumin on their metabolic activity (MTT) and proliferation (BrdU) were studied. The results indicated that NHDFs cells do not survive in presence of C10, as values were close to zero at both days 1 and 7. Moreover, C1 seemed to inhibit proliferation although it did not induce cell death. This was shown by a metabolic activity similar to C0 at both day 1 and 7 (no significant difference), despite the low BrdU values. Interestingly, C0.001 and C0.01 filaments stimulated proliferation of NHDFs compared to the no-filament control. However, this effect was not significant when compared to the filament control C0, meaning that the polymer itself might contribute to improve the cell metabolic activity and proliferation, such as by reacting with the H2O2 present in the medium (added to simulate oxidative stress conditions). Biological characterisation: catalase, GSH, ROS - To assess the antioxidant effect of the curcumin released from the filaments on NHDFs, the activity of catalase and GSH were assessed and the amount of internal ROS was measured. Results indicated that there was no significant change in catalase activity and GSH content between the no-filament control and the filaments C0 to C1. However, both tests showed significantly higher values for C10 compared to the control and compared to the other filaments. Furthermore, a significant reduction in ROS production was observed for C1 and C10 compared to the other samples. Biological characterisation: Scratch test - Scratches were created in cell monolayers and filaments were placed in the ‘wound area’. The wound closure area was assessed over a period of 3 days. Results showed that with filaments C0 to C0.1, cells had filled the wound area by day 3. With C1, although the scratch test results indicated that the average gap area was still of about 50% at day 3, this was not significantly different from the other filaments. The C10 filaments clearly prevented cell proliferation and migration in the vicinity of the filament (placed in the wound area) compared to the controls and to other filaments, as shown by a gap area remaining near 100%. |