امكان‌سنجي سنتز كامپوزيت لوان-ويولاسئين ميكروبي و بررسي خواص آن

Feasibility of Microbial Levan-Violacein Composite Synthesis an‎d Investigation of Its Properties

زيست شناسي سلولي مولكولي و ميكروبيولوژي

Presently, the usage of microbial metabolites in the production of advanced biomaterials, such as nanofibers, has been put into perspective as a green an‎d sustainable approach in nanobiotechnology. In the current study, the feasibility of synthesis of nanofibers containing two microbial metabolites, violacein an‎d levan, via electrospinning method was investigated. Levan was cultivated, isolated, an‎d purified from Zymomonas mobilis ATCC 31821 an‎d violacein with Janthinobacterium lividum DSM 1522. A concentration of 5% polyvinyl alcohol as the base polymer was mixed with various concentrations of violacein (1, 2, 3, 4, 6, an‎d 10%) an‎d levan (3, 5, an‎d 7%), an‎d electrospinning was set up. Morphology of the resulting fibers was examined by light an‎d field emission electron microscopies. Violacein an‎d levan release was investigated. Antioxidant activity was assayed using the 2,2-diphenyl-1-picrylhydrazyl reagent, antimicrobial activity against Staphylococcus aureus ATCC 25922 an‎d Alcaligenes faecalis was assayed with the colony count technique, an‎d cytotoxicity activity against normal L-929 an‎d tumor A-375 cells was assayed with methylthiazolyldiphenyl-tetrazolium bromide. Similarly, flow cytometry was also performed to analyze the effect of the fibers on A-375 cancer cell viability using propidium iodide reagent. Results of light microscopy revealed PV1L7 fiber exhibited most homogenous fiber structure with least bead formation. Confirmation of presence of beads in the fiber structure was established by further investigation of fiber structure through field emission electron microscopy. The average nanofiber diameter was determined to be 0.379 ± 0.092 µm. Release of violacein from the fiber matrix was biphasic an‎d consisted of an initial high-rate release in the first 24 hours followed by a slow an‎d sustained release. In total, around 80% of violacein content was released from the fibers within 72 hours. The PL1V4 fiber sample released the highest amount of violacein. The PV1L7 fibers showed an initial rapid reduction in the number of Staphylococcus aureus an‎d Alcaligenes faecalis cells followed by a slower rate of reduction. Staphylococcus aureus was more susceptible to the fibers compared to Alcaligenes faecalis. The antioxidant activity assay also showed that the PL3V6 fibers showed the highest radical scavenging capacity an‎d up to 79% antioxidant capacity. Cytotoxicity against normal L-929 cells during 24 hours, the PV1L7 fibers showed the best performance. However, when it comes to the anticancer effect of the fibers against A-375 cancer cells, the PL3V6 fibers showed the maximum inhibitory capacity with a viability of 17.17%. PV1L7 sample with uniform fiber formation, low cytotoxicity in normal cells, anticancer activity, an‎d proper antioxidant function was subjected to flow cytometry analysis. Flow cytometry analysis after 24 hours indicated that treatment of A-375 cancer cells with this sample, resulted in 45.36% membrane damage an‎d cell viability loss. These findings suggest the potential future use of violacein-levan fibers in biomedical an‎d therapeutic applications.

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