Biocompatible carbon dots derived from κ-carrageenan and phenyl boronic acid for dual modality sensing platform of sugar and its anti-diabetic drug release behavior.

Detection of sugar by enzymatic assay has been suffering from costly, time-taking, instable and denaturation of glucose oxidase. Recently, chemosensors that have affinity towards boronate became the hot topic in the domain of monosaccharide detection. In this work, a novel strategy was addressed to fabricate carbon dots (C-dots) from linear sulfated polysaccharides κ- carrageenan and phenyl boronic acid for nonenzymatic monosaccharide (glucose) detection. The boronic acid group anchored C-dots surface can form assembly by covalently bonded with the cis-diol moiety of the glucose which caused fluorescence quenching of the C-dots. The inert surface nature of the luminescent C-dots enables them to sense as low as 1.7 µM glucose without the interference of other biomolecules. The proposed sensing system was successfully applied for assay of glucose in blood serum. Interestingly, these C-dots were used as a nano vehicle for delivery of anti-diabetic drug Metformin. Good biocompatibility results were found with MTT and hemolysis assay. Owing to its simplicity and effectiveness, the as-prepared C-dots offered great promise for blood sugar diagnosis and treatment.