Conjugated Polythiophene for Rapid, Simple, and High-Throughput Screening of Antimicrobial Photosensitizers.

The cationic conjugated poly[3-(3'-N,N,N-triethylamino-1'-propyloxy)-4-methyl-2,5-thiophene hydrochloride] (PMNT) has been developed for high-throughput screening of photodynamic antimicrobial chemotherapy photosensitizers (PSs). The bacterial number can be detected quantitatively by PMNT via various fluorescence quenching efficiencies. The photosensitized inactivation of bacteria is not efficient with ineffective PSs, and thus the bacteria grow exponentially and can be coated tightly by PMNT through electrostatic and hydrophobic interactions, resulting in aggregates and fluorescence quenching of PMNT, whereas, conversely, effective PSs lead to original and strong fluorescence of PMNT. This new platform of high-throughput screening is promising for discovering new PSs.