Morphological Analysis of Antibiotic-Resistant KPC Cells

Untreated KPC cells (negative control), those treated with imipenem (positive control), and those treated with ZnO-NPs (tested sample) were characterized by SEM to study the morphological cell alterations. The concentration of imipenem for positive control was 500 mg/ml, while for the tested bacteria, the MIC concentration was 0.5 mg/ml. The treated KPC cells were fixed with 2.5% glutaraldehyde in a phosphate buffer with pH 7.2. The samples were post-fixed in 1% osmium tetroxide, followed by dehydration through an ascending ethanol series to critical point drying and coating with Au–Pd (80:20) using a Polaron E5000 sputter coater (Quorum Technologies, Laughton, UK). The samples were analyzed by SEM (FEI Quanta 250) at an accelerating voltage of 25 kV using an SE detector (Kim et al., 2014 (link); Kelly et al., 2017 (link)).