A review: Aptamer-based analytical strategies using the nanomaterials for environmental and human monitoring of toxic heavy metals

Recent developments in biotechnology offer the new methods for the sensitive detection of heavy metals based on the affinity and specificity of aptamers, as nucleic acid ligands selected from random sequence pools in vitro. Heavy metals have received considerable importance as the most toxic metallic pollutants which may cause serious environmental damages. They are classified as trace elements because of their presence in trace concentrations in various environmental matrices. Thus, the precise and sensitive methods to detect heavy metals are important to ensure human and environment safety. Aptamers as the biological probes, show high binding affinity which can often be directly translated into high detection sensitivity. On the other hand, high selectivity and stability make them possible to detect a wide range of targets, especially metallic ions. This review provides current progress of aptamers for environmental and biological monitoring of heavy metals using the nanomaterials mainly in two groups: (i) aptamer based biosensors (aptasensors) and (ii) aptamer based biosorbents (aptasorbents). The introduction of nanomaterials can efficiently increase the immobilization quantity of aptamers. Furthermore, they play an important role in the orientation and assembly density controlling of aptamers for the optimized recognition ability.