Two-dimensional array of ZnSe-ferritin nanodots as a sensor media for gamma-aminobutyric acid

Quantum dots have been attractive especially in the area of biosensors due to their peculiar optical properties. In this context, less toxic Zinc selenide (ZnSe) quantum dots were synthesized in the cavity of the apoferritin from horse spleen (HsAFr), and the two-dimensional ZnSe-ferritin nanodots were prepared on modified silicon surface. For utilizing the array as a biosensor, the photoluminescence (PL) spectrum change was investigated by accompanying its conjugation reaction with gamma-aminobutyric acid (GABA) and glutamic acid, where GABA is a major inhibitory neurotransmitter in the central nervous system and glutamic acid is its physiological precursor. The results revealed that the fluorescence intensity of ZnSe quantum dots in ferritin core is dependent on the concentration of GABA and the enhancement factor was a linear function of the GABA concentration in the range of 0.03 to 0.18μM despite the presence of glutamic acid. Accordingly, the ZnSe-ferritin nanodot arrays can be employed as a useful sensing media for even very tiny concentration of neurotransmitter GABA.