Stripping metalloprotein with bismuth nanomaterials tethered on carbon surface

An increasing number of metalloproteins has shown to play essential roles in physiological processes. The Zn(II)-dependent metalloprotein, carbonic anhydrase (CA), is a hallmark of metabolic change in cancer cells. Being able to evaluate CA expression is crucial for the early detection of malignant tissues. The fabrication of sensor based on bismuth nanomaterials tethered on mesoporous carbon through a conductive spacer arm is reported. By coupling this hybrid material with stripping analysis, its functionality in measuring CA levels in body fluids is validated. Notably, the zinc finger metalloprotein biosensor system successfully and reliably tunnels zinc within the protein shell allowing the detection of increased concentrations of metalloproteins in saliva. The sensor displays high specificity, sensitivity, repeatability, and most of all a limit of detection of 4.8 ng.ml(-1) for zinc ions and 11 ng.ml(-1) for CA metalloprotein. Given the clinical significance of carbonic anhydrase in tumour development, these findings are the first step towards fast, low cost and stable sensor technology and will revolutionize the field of cancer diagnosis.