Two cationic conjugated polyelectrolytes (CPEs) based on poly(phenylene ethynylene) are found to exhibit efficient 2-photon excited fluorescence. In particular, the CPE aggregates display enhanced 2-photon absorption compared to the nonaggregated states. The CPEs are used as 2-photon absorption sensitizers to harvest light and amplify the fluorescence from green fluorescent protein (GFP) through Förster resonance energy transfer. Considerably enhanced GFP fluorescence under near-infrared 2-photon excitation is demonstrated both in solution and in HeLa cells. The results suggest applications in 2-photon fluorescence imaging of cells, tissues, and organs of living animals expressing GFP.
All Science Journal Classification (ASJC) codes
- General Chemistry
- General Chemical Engineering
- Materials Chemistry