Synthesis & Characterization of GQDs as a Potential Sensing Material for Detection of Cystic Fibrosis

Abstract

Cystic Fibrosis is a rare hereditary disorder that causes dysfunctionality of chloride channels in the membrane of cells. Hallmark of cystic fibrosis is an increased amount of chloride in sweat. Conventionally, a sweat test requires a large volume of sweat. The collection of sweat samples takes a long time and causes inconvenience to the patient and delays in diagnosis. Developing economical and sensitive chloride detectors using graphene nanoparticles is an emerging research field in nanobiotechnology. Chloride ion concentration in sweat samples is a determinant of cystic fibrosis. The objective of this project was the optimized synthesis of graphene quantum dots (GQDs) and characterization to evaluate its potential for being used in chloride detection. GQDs were synthesized by the carbonization of citric acid. Fluorescence was tested using a 365 nm UV lamp. Samples giving strong fluorescence were selected for characterization through UV- vis spectroscopy and FTIR (Fourier-transform infrared spectroscopy). GQDs were fused onto the glass electrodes using BSA (Bovine serum albumin). Blue fluorescence of the sample under UV light confirmed the carbonization of citric acid into GQDs. UV-vis spectrum and FTIR peaks revealed surface functionalization and quantum size of particles. UV-vis spectrum indicated a characteristic peak of blue GQDs. FTIR spectrum indicated carboxylic groups anchored to the GQDs surface. It was concluded that surface functionalization of GQDs allow easy adsorption onto electrodes and can serve as a potential nanomaterial for electrochemical chloride sensor.