Multiregulation of Aggregation-Induced Emission (AIE) via a Competitive Host-Guest Recognition and α-Amylase Hydrolyzing

The multiregulation of aggregation-induced emission (AIE) that responds to external stimuli to finish multifunctions has become a focus of interest in biodiagnosis. Host-guest-recognition is an efficient strategy to introduce switchable, reversible, and other functional properties into AIE molecules. Herein, an amphiphilic tetraphenylethylene (TPE) derivative TPE-PEG is prepared via the simple amidation reaction and chosen as an AIE-based guest polymer. The aggregated state of TPE-PEG is altered and the fluorescence of TPE-PEG can be turned off in the presence of gamma-cyclodextrins (gamma-CDs) due to the formation of host-guest complex between TPE units and gamma-CDs. TPE units in the cavities of gamma-CDs are released free and an aggregated state of TPE-PEG is restored via the guest competition epistasis of bile acid. Meanwhile, alpha-amylase can hydrolyze the host molecules of gamma-CDs, resulting in an aggregated state of TPE-PEG again and turning the fluorescence on subtly. This reversible multiregulation of fluorescence may meet the multirequirements for the diagnosis in vivo due to the biological nature of alpha-amylase and bile acid.