Artificial Tendons' Responsiveness to Mechanical Stress and Biological Performance Following Cork Extract...

Hand tendon ruptures have increased due to mechanical stress, degeneration, trauma, and repetitive motion. This study proposes an artificial tendon engineered from polymeric braids made of lyocell, biodegradable polyester, and polyethylene terephthalate, functionalized with natural cork extract. Cork extract 2, obtained by cork powder using hydroethanolic solvent in a planetary mixture, exhibited a phenolic content of 508.35 ± 82.26 mg GAE/g, flavonoid content of 607.32 ± 63.96 mg EQ/g, strong antioxidant activity (EC₅₀ = 0.21 ± 0.02 mg/mL), and antimicrobial efficacy, with minimum bactericidal concentrations of 0.16 mg/mL against Staphylococcus aureus and 0.64 mg/mL against Pseudomonas aeruginosa. Single-polymer braids were processed with a core-shell structure, in which the core was formed of loose strands. The mechanical characterization of the braids showed the three polymers to exhibit an elongation at break of 8.72 ± 2.05-18.72 ± 6.58% and tensile strength of 44.22 ± 12.02-53.15 ± 12.62 MPa, all within desirable ranges for hand tendon repair/substitution. Braids were functionalized via physical adsorption of cork extract 2 (1.60 mg/mL), achieving loading values between 0.33 ± 0.16 and 0.55 ± 0.14 mg/mL. The presence of extract in the braids was confirmed via infrared spectroscopy and through thermal characterization, thermogravimetry, and differential scanning calorimetry. Functionalized braids exhibited controlled release of the cork extract 2, ranging from 1.57 ± 4.14 to 13.90 ± 2.02% within 24 h, ensuring sustained bioactivity, demonstrating as well strong antioxidant activity (87.42 ± 1.18 reduced 2,2-diphenyl-1-picrylhydrazyl), antimicrobial activity (achieving up to 99% reduction in S. aureus and 80% reduction in P. aeruginosa), and low cytotoxicity (>70% metabolic activity); with the functionalized lyocell presenting the best overall performance. In general, the proposed strategy demonstrated promise for hand tendon repair, offering a potential innovative solution to improve patients' quality of life.