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The increasing presence of contaminants in food or drinking water that are capable of causing intoxication, diseases or chronic illness, has stressed the need for analytical systems capable of sensitivity and specificity, especially are analytical systems capable of rapid multi-analyte measurements of complex samples. Metal nanoparticles, especially gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) were widely used in biological sensor strategy, based on their bio-tolerance, unique optical property and other important characteristics. Aptamers are artificial nucleic acid ligands, specifically generated against certain targets, such as amino acids,drugs, proteins or other molecules. In nature they exist as a nucleic acid based genetic regulatory element called a riboswitch. For generation of artificial ligands, they are isolated from combinatorial libraries of synthetic nucleic acid by exponential enrichment, via an in vitro iterative process of adsorption, recovery and re-amplification known as systematic evolution of ligands by exponential enrichment (SELEX). Comparing with antibody, aptamer has many advantages. They are chemically stable, conveniently available via chemical synthesis, and less vulnerable to denaturation, that make them very promising for analytical applications.