Rapid and sensitive detection of lysophosphatidylcholine using zwitterionic polydiacetylene vesicles and a microfluidic gradient sensor

Abstract

Lysophosphatidylcholine (LPC), a major phospholipid component of atherogenic lipoproteins, induces apoptosis of vascular smooth muscle cells and promotes arteriosclerosis. We developed both a solution-type colorimetric sensor and a fluorescence-based microfluidic gradient sensor that rapidly analyzes LPC in solution at the level of a few tens of micromolar. Zwitterionic polydiacetylene (PDZ) vesicles displayed a blue to purple-red color change and a fluorescence turn-on feature upon interaction with LPC as a result of the electrostatic and hydrophobic interaction between LPC and PDZ vesicles. The zwitterionic PDZ sensor system also displayed a remarkable substrate selectivity for LPC among various structural analogues. Significantly, we developed a multichannel microfluidic gradient sensor and on-chip fluorescence detection technique that can be utilized to simultaneously measure the LPC concentrations of seven solution gradients under flowing conditions within 10 min. The analytical system developed in this study is expected to be useful as a rapid in vitro diagnostic sensor for LPC, a biomarker for assessing the risk of developing arteriosclerosis.