Phthalocyanine‐Sensitized Graphene–CdS Nanocomposites: An Enhanced Photoelectrochemical Immunosensing Platform

Abstract

A novel strategy is developed for the fabrication of graphene-CdS (G-CdS) nanocomposites by in situ growth of CdS nanoparticles onto simultaneously reduced graphite oxide, which is noncovalently functionalized by sodium 1-pyrene sulfonate through strong π-π stacking interactions. Subsequently, cobalt 2,9,16,23-tetraaminophthalocyanine (CoTAPc) is self-assembled on the G-CdS nanocomposites through electrostatic interactions to produce phthalocyanine-sensitized G-CdS nanocomposites. The photoactive superstructure enhances the photocurrent generation capability, and presents an efficient photoelectrochemical immunosensing platform for the ultrasensitive detection of the prostate-specific antigen (PSA). The quantitative measurement of PSA is based on the decrease in the photocurrent intensity of the phthalocyanine-sensitized G-CdS nanocomposites, which results from an increase in the steric hindrance due to the formation of the immunocomplex. A linear relationship between the photocurrent decrease and the PSA concentration is obtained in the wide range from 1 pgmL(-1) to 5 μgmL(-1) with a detection limit of 0.63 pgmL(-1). The proposed sensor shows high sensitivity, stability, reproducibility, and can become a promising platform for other biomolecular detection.

A versatile immobilization-free photoelectrochemical biosensor for ultrasensitive detection of cancer biomarker based on enzyme-free cascaded quadratic amplification strategy

“…To date, many approaches have been successfully developed for pursuing the exploration of extreme detection sensitivity toward cancer biomarkers (Chikkaveeraiah et al, 2012;Ding et al, 2015;Wu et al, 2007). Among these approaches, photoelectrochemical (PEC) biosensor is a newly emerged approach for the rapid and sensitive detection of cancer biomarkers (Fan et al, 2014;Hu et al, 2013;Li et al, 2013Li et al, , 2015Wang et al, 2009;Zeng et al, 2014aZeng et al, , 2014bZhang et al, 2014;Zhao et al, 2012a) and has drawn more and more concerns (Yang et al, 2015a(Yang et al, , 2015bZhao et al, 2014). Coupling photo-excitation with a current readout, PEC biosensors have inherited the advantages from both optical and electrochemical methods Ma et al, 2015) and offered a promising analytical platform for cancer biomarkers detection with greatly reduced background signals and strikingly improved sensitivity.…”

Quantum dot-based photoelectric conversion for biosensing applications

“…The formation of the immunocomplex led to the decrease of photocurrent, then the signal changed before and after the formation of the immunocomplex could be used to construct a simple label-free PEC immunosensor with. [75]. Then, cobalt 2,9,16,23-tetraaminophthalocyanine (CoTAPc) was self-assembled on the hybrid nanomaterial through electrostatic interactions and formed a phthalocyanine-sensitized GR-CdS probe.…”

An enhanced photoelectrochemical immunosensing platform: Supramolecular donor–acceptor arrays by assembly of porphyrin and C 60

“…In the case of PEC detection process, light is used to excite active species on the electrode, and current is used as the detection signal, which is just the reverse process of electrochemiluminescence (Li et al, 2013;Zhao et al, 2014). Benefiting from the different forms of energy for excitation and detection, the sensitivity and specificity of PEC could potentially match that of the electrochemiluminescence.…”