Bacterial attachment on poly[acrylonitrile-co-(2-methyl-2-propene-1-sulfonic acid)] surfaces

Abstract

The influence of material properties on bacterial attachment to surfaces needs to be understood when applying polymer-based biomaterials. Positively charged materials can kill adhered bacteria when the charge density is sufficiently high [1] but such materials initially increase the adherence of some bacteria such asEscherichia coli [2]. On the other hand, negatively charged materials have been shown to inhibit initial bacterial adhesion [3], but this effect has only been demonstrated in relatively few biomaterial classes and needs to be evaluated using additional systems. Gradients in surface charge can impact bacterial adhesion and this was tested in our experimental setup.

Moreover, the evaluation of bacterial adhesion to biomaterials is required to assess their potential for biological applications. Here, we studied the bacterial adhesion ofE. coli andBacillus subtilis on the surfaces of acrylonitrile-based copolymer samples with different amounts of 2-methyl-2-propene-1-sulfonic acid sodium salt (NaMAS) comonomer. The content related to NaMAS based repeating units n_NaMAS varied in the range from 0.9 to 1.5 mol%.

We found a reduced colonized area ofE. coli for NaMAS containing copolymers in comparison to pure PAN materials, whereby the bacterial colonization was similar for copolymers with different n_NaMAS amounts. A different adhesion behavior was obtained for the second tested organismB. subtilis, where the implementation of negative charges into PAN did not change the overall adhesion pattern. Furthermore, it was observed thatB. subtilis adhesion was significantly increased on copolymer samples that exhibited a more irregular surface roughness.