Nanomaterial-based ‘chemical nose’ sensor with sufficient sensing specificity is a useful analytical tool
for the detection of toxicologically important substances in complicated biological systems. A sensor
array containing three quaternized magnetic nanoparticles (q-MNPs)–fluorescent polymer systems has
been designed to identify and quantify bacteria. The bacterial cell membranes disrupt the q-MNP–
fluorescent polymer, generating unique fluorescence response array. The response intensity of the array
is dependent on the level of displacement determined by the relative q-MNP–fluorescent polymer
binding strength and bacteria cells–MNP interaction. These characteristic responses show a highly
repeatable bacteria cells and can be differentiated by linear discriminant analysis (LDA). Based on the
array response matrix from LDA, our approach has been used to measure bacteria with an accuracy of
87.5% for 107 cfu mL1 within 20 min. Combined with UV–vis measurement, the method can be
successfully performed to identify and detect eight different pathogen samples with an accuracy of
96.8%. The measurement system has a potential for further applications and provides a facile and simple
method for the rapid analysis of protein, DNA, and pathogens