Plasma treatment and chitosan coating: a combination for improving PET surface properties

There are growing advantages of using electrospun poly(ethylene terephthalate) (PET) mats for tissue engineering purposes. However, because of poor surface physicochemical properties, using PET as a biomaterial may have some serious problems, such as poor wettability, inappropriate surface roughness and consequently weak cell attachment. To avoid such complications, in the present study, a combination of nanosecond pulsed plasma surface modification and chitosan coating was used as a versatile solution for tackling the mentioned problems. The effects of plasma treatment and chitosan coating were characterized by scanning electron microscopy, goniometry, weight loss study and X-ray photoelectron spectroscopy. The results showed that plasma modification resulted in the introduction of active polar oxygen (O)-containing functional groups onto the PET surface. The PET mat exhibited over 30 and 25% enhancement of hydroxyl and carboxyl groups after plasma treatment, respectively. Consequently, the oxygen/carbon (C) ratio increased from 0·36 to 0·73. These modifications led to improvement of physical properties, such as a significant increase in wettability and chitosan deposition. Chitosan coating introduced new nitrogen (N)-containing functional groups, which were absent in the uncoated PET. Plasma treatment increased the nitrogen/carbon ratio of chitosan-coated samples by a factor of 2. The obtained results suggest an enhancement in surface physicochemical properties with noteworthy potential applications in tissue engineering scaffolds.