A cost-effective and rapid quantitative test of polymyxin B sulphate with a simple and portable pressure meter readout†
Any signals, if their intensities have a simple functional relationship with analyte concentration, can be applied for analytical purposes. Among them, pressure measurement as a signalling technique has been extensively utilized to develop portable and quantitative bioanalysis, with the advantages of highly sensitive detection of a variety of biomedical targets. In this contribution, it was found that polymyxin B sulphate (PMB) could significantly inhibit the catalytic ability of platinum nanoparticles (PtNPs) prepared in different protocols in the H2O2 breakdown reaction. By employing sodium citrate as the reducing agent to prepare the platinum nanoparticles (C-PtNPs) as an example and monitoring the pressure signal changes of the C-PtNP catalyzed H2O2 breakdown against the reaction time, a sensitive, cost-effective, rapid and reliable analysis method for PMB is established on the basis of the pressure signal readout. The proposed method has a detection limit of 28.6 nM and can selectively detect PMB in both POLY-MxB powder injection and human urine samples, demonstrating its potential in bioanalysis, which would be significant to address biological, clinical and medicinal requirements.