A biosensor for the selective capture and detection of prostate cancer cells in urine
Prostate cancer is the most commonly diagnosed cancer in men and, while a range of invasive and non-invasive diagnostic tests exist, identifying aggressive and life-threatening cases is a real challenge.
For example, the poor specificity of PSA blood tests (prostate specific antigen) leads to overdiagnosis and overtreatment. More than 600,000 PSA tests are performed in Australia each year. The results of the PSA test prescribe in excess of 25,000 invasive and painful prostate biopsies (trans-rectal or trans-perineal), each of them costing around $2,000 to Medicare ($50M p.a) while in 70% of cases, no cancer is found.
The spontaneous shedding of prostate cancer cells into urine provides non-invasive potential for the establishment of more accurate prostate cancer routine diagnostics.
We have developed a technology for the capture and detection of prostate cancer cells from urine samples that is non-invasive, easy to use, and, based on pilot in-vitro results, is highly specific.
Antibodies to Prostate Specific Membrane Antigen (PSMA), a membrane marker over-expressed in prostate cancer, were irreversibly bound to plasma-coated biomaterial sensors. The biofunctionalisation step occurs in physiological buffer without additional reagents. On these bioengineered substrates, we have achieved the selective immunocapture of prostate cancer cell lines spiked in healthy urine samples with 94% sensitivity and 97% specificity. A distinctive detection method based on the specific porphyrin fluorescence of cancer cells is incorporated into the prototype point-of-care device to allow for automated cell detection. The diagnostic device is now used to screen voided urine samples collected from patients in clinical trials.
This technology is relevant for the biomedical point of care diagnostic market.