Development of luminescence materials as chemo-sensor for the detection of anionic, cationic or neutral molecules in environmental/biological samples attracts a great attention and is a growing research field. Among novel materials, supra-molecules are being considered for specific binding of analytes, since these compounds can exhibit distinct spectral behavior after binding to guest molecules to perform as chemo-sensors. Since most of organic molecules have low solubility in water, its conversion to Organic Nanoparticles represents a simple way to disperse them in water: although organic nano-particles (ONPs) are easily biodegradable in most cases, they are generally unstable, involve quick aggregation, and loose unique spectral features. To overcome these drawbacks, some capping/complexing agents are considered in order to avoid the aggregation as well as to increase the stability. In the present work, thiophene containing Schiff’s base N,N'-bis(thiophene-2-ylmethylene)thiophenemethane was synthesized and later applied as fluorescent probe for recognition of specific biomolecules in aqueous media (cysteine and cytosine), showing no interference from close related molecules such as guanine, uracyl, NADH, NAD, ATP and adenine. Size and morphology of prepared particles was determined by Transmission Electron Microscope (TEM) and Dynamic Light Scattering. Results show AuNPs embedded within a low-density matrix of organic matter (ONPs) that increases stability of ONPs and its fluorescent emission in a wide pH range. Limit of Detection (LOD) for cysteine and cytosine was determined to be 2.12 nM and 258.36 nM respectively. In the interaction of cells with Au-ONPs, cysteine does not exhibit fluorescence upon excitation at 405 nm in con-focal microscope in contrast to cytosine which yields to strong fluorescence images. Moreover, <i>Saccharomyces cerevisiae</i> culture in presence of Au-ONPs showed internalization of nanoparticles and obtained cells were used as biomarker recognize cysteine and cytosine.

Fluorescent biomarker: Detection of cysteine and cytosine in aqueous medium using thiophene based organic nanoparticles decorated with Au NPs

2019 Spring National Meeting

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