Spectroscopic and structural characterization of human amniotic membrane after washing with plasma-activated water

The human amniotic membrane (AM) is widely used in regenerative medicine; however, tissue processing and sterilization procedures may compromise its structural integrity. Plasma-activated water (PAW) has emerged as a potential alternative for tissue decontamination. This study evaluated the effects of PAW washing on the structural and molecular characteristics of human AM using histological and Fourier-transform infrared (FTIR) spectroscopy analyses. AM fragments were divided into two groups: a PAW group, washed with plasma-activated water, and an antibiotic group (ATB), washed with penicillin, streptomycin, and amphotericin B. Following treatment, the fragments were cryopreserved and subsequently evaluated by histology and FTIR spectroscopy. Histological analysis revealed no apparent differences between the groups. FTIR analysis showed differences in band intensity in the amide III region on both membrane surfaces, while an additional difference at 1743 cm^-1 was observed on the mesenchymal layer. Hierarchical cluster analysis (HCA) of the 1400-1700 cm^-1 spectral region showed high similarity between the PAW and ATB groups. Principal component analysis (PCA) primarily separated samples according to membrane surface rather than treatment. Overall, PAW washing did not induce detectable histological or molecular alterations in human AM compared with conventional antibiotic washing.