To evaluate the efficacy of delivering antibiotics in response to tensile strain-induced mechano-activation, 5% (w/v) CIF is encapsulated in inner core of the microcapsules. After stretching to strains of 20% or 50%, 50 μL of fresh PBS solution is dropped onto the microcapsules-laden gauze to collect the released CIF. The amount of released CIF is quantified by measuring the absorbance at 277 nm using the UV-Vis spectrometer (n ≥ 500 microcapsules/loading regimen/type, 4 specimens/loading regimen/type).
The impact of CIF delivery from mechano-activated PDA-MAMCs is also assessed by analyzing antibacterial performances of the microcapsule-loaded gauzes against E. coli JM109 strain using the Kirby-Bauer method.47 (link) Gauze specimens of 8 mm diameter are placed on Luria-Bertani (LB) agar plates (Sigma-Aldrich) seeded with 100 μL of log-phase bacterial cells, and are incubated at 37 °C for 24 h. The area of inhibition zone is measured using Image J (n ≥ 3 specimens/type). The colony forming units (CFU) are also counted after incubation of the microcapsule-loaded gauzes at 37 °C for 24 h in 500 μL of LB medium seeded with bacterial cells in a log-phase at 1:100 (v/v) in a tissue culture plate. Relative bacterial cell viability is determined by dividing the CFU count in culture broth with the gauze specimens or soluble CIF by the CFU count without the gauze (n ≥ 3 specimens/type).
The impact of CIF delivery from mechano-activated PDA-MAMCs is also assessed by analyzing antibacterial performances of the microcapsule-loaded gauzes against E. coli JM109 strain using the Kirby-Bauer method.47 (link) Gauze specimens of 8 mm diameter are placed on Luria-Bertani (LB) agar plates (Sigma-Aldrich) seeded with 100 μL of log-phase bacterial cells, and are incubated at 37 °C for 24 h. The area of inhibition zone is measured using Image J (n ≥ 3 specimens/type). The colony forming units (CFU) are also counted after incubation of the microcapsule-loaded gauzes at 37 °C for 24 h in 500 μL of LB medium seeded with bacterial cells in a log-phase at 1:100 (v/v) in a tissue culture plate. Relative bacterial cell viability is determined by dividing the CFU count in culture broth with the gauze specimens or soluble CIF by the CFU count without the gauze (n ≥ 3 specimens/type).