Self-assembled diphenylalanine-zinc oxide hybrid nanostructures as a highly selective luminescent biosensor for trypsin detection

The ability of Diphenylalanine (FF) dipeptide, to form nanotubes of different aspect ratios in varying solutions can be manipulated in presence of inorganic nanomaterials. In this regard, the self-assembly of FF nanostructures in the presence of Zinc oxide (ZnO) nanoparticles, suspended in ethanol, deionized (D.I) water and phosphate buffer saline (PBS) are investigated for the first time. A comparative study of pristine and hybrid nanostructures dispersed in respective solutions reveal the variation in morphological and electrochemical properties. These as-prepared nanostructures display unique structural transitions with distinctive luminescent properties; FF-ZnO hybrid nanostructures in ethanol and D.I water display orange emission, while in PBS displays blue emission as a result of defect and near band-edge emission (NBE) of ZnO, respectively. Furthermore, this luminescent characteristic of the hybrid material is found to have promising application for biosensing, as a cutting-edge probe for sensitive detection of trypsin. The contrivance of the system is based on the trypsin digestion on the surface of FF-ZnO nanostructures exhibiting an enhanced emission (550 nm) with 0-160 ng mL(-1) detection range and limit of detection of 0.1 ng mL(-1). Finally, these results suggest that the optical and electronic properties of FF can be tuned by incorporation of metal oxide-based nanomaterials for biomedical applications.

Automated summary

By manipulating the self-assembly of Diphenylalanine (FF) dipeptide in the presence of Zinc oxide (ZnO) nanoparticles in different solutions, a hybrid nanostructure with unique luminescent properties was obtained, showing potential for sensitive detection of trypsin for biomedical applications.