Biofilm inhibiting nanocomposite coatings on stainless steel surgical instruments: a possible strategy to prevent TASS

Toxic anterior segment syndrome (TASS) is an inflammation that occurs after anterior segment surgeries, and is widely seen in the patients after cataract surgery. The main cause of TASS is postulated to be the bio-residue and heat stable endotoxins which persist on the used forceps even after autoclave sterilization, some of which are known to cause inflammation. In this work, initially, a detailed characterization of bio-residue composition before and after autoclave sterilization of the forceps used in ophthalmic surgeries was carried out by Fourier-transform infrared spectroscopy (FTIR) and gas chromatography mass spectrometry (GCMS) techniques. The morphological features of biofilm before and after autoclave were also examined using a field emission scanning electron microscope (FESEM). Subsequently, two biofilm inhibiting nanocomposite coating formulations which were earlier developed by us were deposited on stainless steel 420 coupons to mimic surgical instruments. Biofilm inhibition was studied for bare and coated substrates after autoclaving using crystal violet staining as well as by FESEM analysis. It was observed that the coated substrates prevented biofilm formation even after autoclaving. The results of this study demonstrate that the biofilm inhibiting coatings prevent formation of biofilm and hence, prevent deposition of bioresidues on stainless steel surgical instruments. Due to this, the coated surgical instruments are safe to use even after autoclaving and cannot be expected to cause any inflammatory responses after surgeries, thereby preventing TASS.