Structure of Self-assembled Peptide Determines the Activity of Aggregation-Induced Emission Luminogen-Peptide Conjugate for Detecting Alkaline Phosphatase

Anal Chem. 2022 Feb 1;94(4):2236-2243. doi: 10.1021/acs.analchem.1c04936. Epub 2022 Jan 18.

Abstract

The unique property of turning on their fluorescence after aggregation or assembly makes aggregation-induced emission luminogens (AIEgens) ideal luminescent molecules for the construction of self-assembled peptide-based nanoprobes. However, the characteristic highly twisted or propeller-shaped molecular conformation of AIEgens tends to prevent the assembly of AIEgen-peptides. Here, we show that (i) the distance between tetraphenylethene (TPE) and assembled peptides should not be too far (less than five glycines), otherwise the self-assembly of peptides cannot limit the intramolecular rotation of conjugated TPE and the luminous efficiency of TPE-peptide to alkaline phosphatase (ALP) will decrease; (ii) properly increasing the number of amino acids with self-assembly ability (three phenylalanines) can improve their ALP-responsive self-assembly and luminescence ability; (iii) the strategy of co-assembly with a non-AIEgen-capped self-assembled peptide is a simple and effective way to realize the efficient assembly and luminescence of AIEgen-peptides; and (iv) the hydrophilic and hydrophobic balance of the probe should always be considered in the construction of an efficient AIEgen-peptide probe. In addition, AIEgen-peptide probes show good selectivity and sensitivity for ALP detection both in vitro and in live bacteria. These insights illustrated here are crucial for guiding the design of AIEgen-conjugated supramolecular materials, especially for the construction of AIEgen-peptides, for enzymes detection, biomarker imaging, diseases therapy, and other biomedical fields.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaline Phosphatase*
  • Fluorescence
  • Fluorescent Dyes* / chemistry
  • Luminescence
  • Peptides / chemistry

Substances

  • Fluorescent Dyes
  • Peptides
  • Alkaline Phosphatase