Abstract:
We have designed and synthesized novel tetraphenylethylene (TPE) appended organic fluorogens and unfold
their unique Raman fingerprinting reflected by surface-enhanced Raman scattering (SERS) upon adsorption on nanoroughened
gold surface as a new insight in addition to their prevalent aggregation-induced emission (AIE) and aggregation-caused
quenching (ACQ) phenomena. A series of five TPE analogues has been synthesized consisting of different electron donors such
as (1) indoline with propyl (TPE-In), (2) indoline with lipoic acid (TPE-In-L), (3) indoline with Boc-protected propyl amine
(TPE-In-Boc), (4) benzothaizole (TPE-B), and (5) quinaldine (TPE-Q). Interestingly, all five TPE analogues produced
multiplexing Raman signal pattern, out of which TPE-In-Boc showed a significant increase in signal intensity in the fingerprint
region. An efficient SERS nanoprobe has been constructed using gold nanoparticles as SERS substrate, and the TPE-In as the
Raman reporter, which conjugated with a specific peptide substrate, Cys-Ser-Lys-Leu-Gln-OH, well-known for the recognition of
prostate-specific antigen (PSA). The designated nanoprobe TPE-In-PSA@Au acted as SERS “ON/OFF” probe in peace with the
vicinity of PSA protease, which distinctly recognizes PSA expression with a limit of detection of 0.5 ng in SERS platform.
Furthermore, TPE-In-PSA@Au nanoprobe was efficiently recognized the overexpressed PSA in human LNCaP cells, which can
be visualized through SERS spectral analysis and SERS mapping
