In situ FTIR spectroscopy study on biomolecular etching by atmospheric pressure plasma jets

The evaluation of biomolecular etching by non-thermal plasmas is of great significance for surface decontamination but remains a big challenge. In this work, the atmospheric pressure plasma jets etching profiles of over 40 kinds of biological materials were systematically probed by in situ Fourier transform infrared spectroscopy. The infrared spectra were recorded in real time during the plasma exposure processes with the sensitivity of ∼μg. Etching rather than chemical modifications dominated the spectral variations. Results showed that short-carbon-chain or hydroxyl-containing amino acids had much higher etching rates (ERs). Almost all tested proteins shared close ERs, which were higher than those of nucleic acids, peptidoglycan, phospholipid, and serum. Difficultly etched component significantly hindered the overall etching of mixtures. This investigation provides new hints for bacterial or organic contamination removal by plasmas.