Sensing performance of fibronectin-functionalized Au-EGFET on the detection of S. epidermidis biofilm and 16S rRNA of infection-related bacteria in peritoneal dialysis

This study proposed novel methods for Staphylococcus epidermidis biofilm and 16S rRNA of infection-related bacteria detection. S. epidermidis biofilm was attached onto self assembled monolayers (SAMs) coated Au substrate of an extended-gate field-effect-transistor (EGFET) sensor with immobilized extracellular matrix protein, fibronectin. Biofilm mostly composed of positively charged polysaccharide intercellular adhesin (PIA) significantly contributed threshold voltage (V_TH) shift from -6.67 to -94 mV for biofilm yielded by 3.8 × 10⁶ to 3.8 × 10⁸ CFU/ml S. epidermidis and obtained limit of detection (LOD) of 9 × 10⁵ CFU/ml S. epidermidis. SAMs-Au surface functionalization and its properties after fibronectin immobilization showed an optimal surface roughness from atomic force microscope (AFM) view. The presence of biofilm on the surface was validated by (scanning electron microscope) SEM screening after 1 h incubation at 37°C. Cellular response to antibiotic treatment against biofilm achieved as contaminated dialysate was treated with and without Vancomycin. The hybridization of a highly conserved gene, 16S rRNA of S. epidermidis and Staphylococcus aureus, the most leading pathogenic bacteria in peritoneal dialysis patients, was also successfully recorded. Findings suggested that Au-EGFET is a promising sensing biochip for detection of bacterial biofilm and determination of species involved in the infection.