18 research outputs found
Automated 4-sample protein immunoassays using 3D-printed microfluidics
© The Royal Society of Chemistry. Low cost, miniaturized assay platforms that work with small sample volumes, high sensitivity and rapid detection will have high value in future biomolecular diagnostics. Herein we report an automated, 3D printed electrochemiluminescent (ECL) immunoarray integrated with a nanostructured pyrolytic graphite sheet (PGS) microwell chip configured to detect 2 proteins simultaneously from complex liquid samples with high sensitivity and selectivity. Assays are done in 18 min at cost o
Electrochemistry-based approaches to low cost, high sensitivity, automated, multiplexed protein immunoassays for cancer diagnostics
Early detection and reliable diagnostics are keys to effectively design cancer therapies with better prognoses. The simultaneous detection of panels of biomarker proteins holds great promise as a general tool for reliable cancer diagnostics. A major challenge in designing such a panel is to decide upon a coherent group of biomarkers which have higher specificity for a given type of cancer. The second big challenge is to develop test devices to measure these biomarkers quantitatively with high sensitivity and specificity, such that there are no interferences from the complex serum or tissue matrices. Lastly, integrating all these tests into a technology that does not require exclusive training to operate, and can be used at point-of-care (POC) is another potential bottleneck in futuristic cancer diagnostics. In this article, we review electrochemistry-based tools and technologies developed and/or used in our laboratories to construct low-cost microfluidic protein arrays for the highly sensitive detection of a panel of cancer-specific biomarkers with high specificity which at the same time has the potential to be translated into POC applications
Electrochemistry-based approaches to low cost, high sensitivity, automated, multiplexed protein immunoassays for cancer diagnostics
Early detection and reliable diagnostics are keys to effectively design cancer therapies with better prognoses. The simultaneous detection of panels of biomarker proteins holds great promise as a general tool for reliable cancer diagnostics. A major challenge in designing such a panel is to decide upon a coherent group of biomarkers which have higher specificity for a given type of cancer. The second big challenge is to develop test devices to measure these biomarkers quantitatively with high sensitivity and specificity, such that there are no interferences from the complex serum or tissue matrices. Lastly, integrating all these tests into a technology that does not require exclusive training to operate, and can be used at point-of-care (POC) is another potential bottleneck in futuristic cancer diagnostics. In this article, we review electrochemistry-based tools and technologies developed and/or used in our laboratories to construct low-cost microfluidic protein arrays for the highly sensitive detection of a panel of cancer-specific biomarkers with high specificity which at the same time has the potential to be translated into POC applications
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Ultrathin Graphene–Protein Supercapacitors for Miniaturized Bioelectronics
Nearly all implantable bioelectronics are powered by bulky batteries which limit device miniaturization and lifespan. Moreover, batteries contain toxic materials and electrolytes that can be dangerous if leakage occurs. Herein, an approach to fabricate implantable protein-based bioelectrochemical capacitors (bECs) employing new nanocomposite heterostructures in which 2D reduced graphene oxide sheets are interlayered with chemically modified mammalian proteins, while utilizing biological fluids as electrolytes is described. This protein-modified reduced graphene oxide nanocomposite material shows no toxicity to mouse embryo fibroblasts and COS-7 cell cultures at a high concentration of 1600 μg mL-1 which is 160 times higher than those used in bECs, unlike the unmodified graphene oxide which caused toxic cell damage even at low doses of 10 μg mL-1. The bEC devices are 1 μm thick, fully flexible, and have high energy density comparable to that of lithium thin film batteries. COS-7 cell culture is not affected by long-term exposure to encapsulated bECs over 4 d of continuous charge/discharge cycles. These bECs are unique, protein-based devices, use serum as electrolyte, and have the potential to power a new generation of long-life, miniaturized implantable devices
Automated Multiplexed ECL Immunoarrays for Cancer Biomarker Proteins
Point-of-care
diagnostics based on multiplexed protein measurements
face challenges of simple, automated, low-cost, and high-throughput
operation with high sensitivity. Herein, we describe an automated,
microprocessor-controlled microfluidic immunoarray for simultaneous
multiplexed detection of small protein panels in complex samples.
A microfluidic sample/reagent delivery cassette was coupled to a 30-microwell
detection array to achieve sensitive detection of four prostate cancer
biomarker proteins in serum. The proteins are prostate specific antigen
(PSA), prostate specific membrane antigen (PSMA), platelet factor-4
(PF-4), and interlukin-6 (IL-6). The six channel system is driven
by integrated micropumps controlled by an inexpensive programmable
microprocessor. The reagent delivery cassette and detection array
feature channels made by precision-cut 0.8 mm silicone gaskets. Single-wall
carbon nanotube forests were grown in printed microwells on a pyrolytic
graphite detection chip and decorated with capture antibodies. The
detection chip is housed in a machined microfluidic chamber with a
steel metal shim counter electrode and Ag/AgCl reference electrode
for electrochemiluminescent (ECL) measurements. The preloaded sample/reagent
cassette automatically delivers samples, wash buffers, and ECL RuBPY-silica–antibody
detection nanoparticles sequentially. An onboard microcontroller controls
micropumps and reagent flow to the detection chamber according to
a preset program. Detection employs tripropylamine, a sacrificial
reductant, while applying 0.95 V vs Ag/AgCl. Resulting ECL light was
measured by a CCD camera. Ultralow detection limits of 10–100
fg mL<sup>–1</sup> were achieved in simultaneous detection
of the four protein in 36 min assays. Results for the four proteins
in prostate cancer patient serum gave excellent correlation with those
from single-protein ELISA