A disposable aptasensor based on a gold-plated coplanar electrode array for on-site and real-time determination of Cu2+

Copper ion (Cu 2+ ) is an important cofactor for many enzymes in human body. Either excessive or deficient Cu 2+ in the body may cause serious dysfunctions and diseases. So sensitive determination of Cu 2+ in environmental samples is of more significance for evaluation and control of Cu 2+ intake. Based on a low-cost gold-plated coplanar electrode array, a disposable aptasensor is developed with an ultra-sensitive indicator of interfacial capacitance. Modified with a specially isolated DNA aptamer for Cu 2+ , this sensor achieves a high selectivity of 1207: 1 against non-target ions. To realize real-time response, alternating-current electrothermal effect is integrated into the capacitance measuring process to efficiently enrich the trace Cu 2+ . This sensor reaches a limit of detection of 2.97 fM, with a linear range from 5.0 fM to 50 pM. The response time is only 15 s, which can meet the real-time detection requirement. On-site test of practical samples is also realized using the disposable sensor combined with a handheld inductance/capacitance/resistance meter. This sensor with its portable test system provides a cost-efficient solution for on-site, real-time and sensitive detection of Cu 2+ , showing great application value in environment monitoring.