An in-situ plasmonic spectroscopy based biosensor for detection of copper (II) ions highlighting analytical specifications

Whether the copper ion (Cu2+) exposed to us functions as a necessary part of metabolism or toxicant for organs depends on subtle concentration difference of trace-level. Although miniature sensors have combined various recognition probes and signal transducer moieties to form novel sensing scheme, haunting limits on practicality or analytical specifications like sensitivity and selectivity remain thwarting high Cu2+ detection performance with excellent cost-effectiveness. In this work, we report a Cu2+ -specific biosensor integrating Deoxyribozyme (DNAzyme) and single-particle plasmon. The basic principle here is that severity of cleavage corresponding to various Cu2+ concentration determines these elements' aggregation capacity. The evaluation criteria is set up on the shift of dark-field Localized Surface Plasmon Resonance (LSPR) wavelengths caused by the binding with free AuNPs. Not only excellent analytical specifications like limit of detection (LOD) of 0.082 nM, broad dynamic range from 0.1 nM-5 mu M, ultra-specificity are demonstrated but recovery rate with real sample and term of validity is also investigated to be 101.25 +/- 9.15 % at 3 nM and longer than 9 days corroborating its potential for practical scenario. Therefore, the sensor is introduced as an attract alternative to remove hindrances for high sensing performance and to generalize on-chip cleavage-inducing spectral shift to heavy metal ions concentration measurement.

Automated summary

This study introduces a Cu2+-specific biosensor combining DNAzyme and single-particle plasmon, demonstrating excellent analytical specifications and performance. By measuring the cleavage severity corresponding to Cu2+ concentration and evaluating the shift in dark-field LSPR wavelengths caused by binding with free AuNPs, the sensor shows great potential for a wide range of applications.