Research Assistant , University of Connecticut
Development of less expensive more sensitive ELISA using 3D printing
Protein assays are a corner stone in any clinical diagnosis and blood work. Current techniques are highly costly and time consuming mainly due to drawbacks in the automation process. Although fully automated devices are available, it is still difficult to commercialize them due to very complex engineering and reagents control which lead to huge instruments that are very expensive. Using 3D printers we develop an easily controlled protein assay containers as a next generation tool. Integration of this technique in fully automated devices would eliminate the need for complex engineering and fluid control with anticipated tremendous reduction in device size and cost. We applied this new technique in detection of four different proteins that are cancer specific and got better sensitivities compared to current commercial technique.
Abstract: Ultrasensitive mediator-free electrochemical detection for biomarker proteins was achieved at low cost using a novel composite of Fe3O4 nanoparticles loaded onto graphene oxide (GO) nano-sheets (Fe3O4@GO). This paramagnetic Fe3O4@GO composite (1µm size range) was decorated with antibodies against prostate specific antigen (PSA) and prostate specific membrane antigen (PSMA), and then used to first capture these biomarkers and then deliver them to an 8-sensor detection chamber of a microfluidic immunoarray. Screen-printed carbon sensors coated with electrochemically reduced graphene oxide (ERGO) and a second set of antibodies selectively capture the biomarker-laden Fe3O4@GO particles, which subsequently catalyze hydrogen peroxide reduction to detect PSA and PSMA. Accuracy was confirmed by good correlation between patient serum assays and enzyme-linked immuno-sorbent assays (ELISA). Excellent detection limits (LOD) of 15 fg/mL for PSA and 4.8 fg/mL for PSMA were achieved in serum. The LOD for PSA was 1000-fold better than the only previous report of PSA detection using Fe3O4. Dynamic ranges were easily tunable for concentration ranges encountered in serum samples by adjusting the Fe3O4@GO Concentration. Reagent cost was only $0.85 for a single 2-protein assay.
Pub.: 06 Jan '17, Pinned: 10 Aug '17