Novel dual-emissive fluorescent silicon nanoparticles for detection of enzyme activity in supplements associated with lactose intolerance

Abstract

A novel kind of dual-emissive Rhodamine 6G modified silicon nanoparticles (SiNPs-Rho6G) was synthesized through a facial one-pot hydrothermal method. This dual-emissive SiNPs-Rho6G with emission wavelength at 415/550 nm under 320 nm excitation possessed the advantages of strong fluorescence and photostability. SiNPs-Rho6G was developed to set up a ratiometric fluorescence sensor toward β-Galactosidase (β-Gal) activity with p-Nitrophenol (PNP) involved. PNP was the hydrolysis product of p-Nitrophenyl-β-d-Galactopyranoside. It quenched the fluorescence of SiNPs-Rho6G at 415 nm with a red shift in the company of β-Gal due to inner filter effect, and the fluorescence at 550 nm changed slightly under the maximum excitation wavelength of 320 nm. The activity of β-Gal was determined in a range of 1–25 U·L−1 with a limit of detection of 0.72 U·L−1. The proposed method was further utilized to determine the β-Gal activity in enzyme formulations for alleviating lactose intolerance with high sensitivity and selectivity. Moreover, this method was proved to have the potential of being an analysis platform for various target molecules in the field of medicine, food and drug.