Pathogenic detection and phenotype using magnetic nanoparticle-urease nanosensor

The diagnoses of bacterial infections remain a challenge in environment safety and human health area. Nanomaterial-based ‘enzyme nose’ sensor is a useful analytical technique for the detection of toxicologically important targets in biological samples. In this paper, we used three quaternized magnetic nanoparticles–urease sensors to detect bacteria with excellent sensitivity for several gram-positive or gram-negative bacteria. The response intensity of the nanoarray sensor is dependent on the level of displacement determined by three quaternized magnetic nanoparticles–urease binding strength and pathogenic cells–nanoparticles interaction. Based on the ability of urease to hydrolyze urea and increase the pH value of the system, the detection of pathogen is translated into a pH increase, which can be readily detected using a litmus dye. These characteristic responses of color show repeatable pathogenic cells and can be differentiated by principle component analysis (PCA). Our approach has been used to measure bacteria with an accuracy of 90.7% for 102 cfu mL−1 within 30 min. The measurement system has a potential for further applications and provides a facile and simple method for the rapid analysis of pathogens.