Aptamer-functionalized graphene-gold nanocomposites for label-free detection of dielectrophoretic-enriched neuropeptide Y

Fernandez, Renny Edwin; Sanghavi, Bankim J.; Farmehini, Vahid; Chávez, Jorge L.; Hagen, Joshua A.; Kelley‐Loughnane, Nancy; Chou, Chia-Fu; Swami, Nathan S.

doi:10.1016/j.elecom.2016.09.017

Cited by 37 publications

(23 citation statements)

References 26 publications

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“…However, a number of methodologies have recently emerged 199 , including those using conducting polymers 200 , silver-PDMS 201 , liquid metals 202 , screen printing 203 and vapor deposition, constructed by techniques of micromolding 204 , semiconductor fabrication 205,206,207,208,209 , and low-cost bonding methods on hybrid platforms 210,203 . The reduced dead volumes of such 3D electrode platforms have been applied to enhance the spatial extents of the field non-uniformity 211,212 to enable high throughput separations 213,214 , cytometry 215,216 , sample enrichment for biomolecular determination 217,218 , sample transport by traveling-wave dielectrophoresis 219,220,221 , and dielectric characterization of cells by electro-rotation 222,223,224 .…”

Section: Challenges and Emerging Needsmentioning

confidence: 99%

Review: Microbial analysis in dielectrophoretic microfluidic systems

Fernandez

Rohani

Farmehini

et al. 2017

Analytica Chimica Acta

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125

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Infections caused by various known and emerging pathogenic microorganisms, including antibiotic-resistant strains, are a major threat to global health and well-being. This highlights the urgent need for detection systems for microbial identification, quantification and characterization towards assessing infections, prescribing therapies and understanding the dynamic cellular modifications. Current state-of-the-art microbial detection systems exhibit a trade-off between sensitivity and assay time, which could be alleviated by selective and label-free microbial capture onto the sensor surface from dilute samples. AC electrokinetic methods, such as dielectrophoresis, enable frequency-selective capture of viable microbial cells and spores due to polarization based on their distinguishing size, shape and sub-cellular compositional characteristics, for downstream coupling to various detection modalities. Following elucidation of the polarization mechanisms that distinguish bacterial cells from each other, as well as from mammalian cells, this review compares the microfluidic platforms for dielectrophoretic manipulation of microbials and their coupling to various detection modalities, including immuno-capture, impedance measurement, Raman spectroscopy and nucleic acid amplification methods, as well as for phenotypic assessment of microbial viability and antibiotic susceptibility. Based on the urgent need within point-of-care diagnostics towards reducing assay times and enhancing capture of the target organism, as well as the emerging interest in isolating intact microbials based on their phenotype and subcellular features, we envision widespread adoption of these label-free and selective electrokinetic techniques.

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Section: Challenges and Emerging Needsmentioning

confidence: 99%

Review: Microbial analysis in dielectrophoretic microfluidic systems

Fernandez

Rohani

Farmehini

et al. 2017

Analytica Chimica Acta

Self Cite

125

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“…Details of the device geometry and operation are available in prior work 22,26,35 and in Supporting Information †. Briefly, four reservoirs lead to a microchannel of 5 µm depth and several nanoslits of 200 nm depth, 30 µm width and 300 µm length.…”

Section: Experimental Methodsmentioning

confidence: 99%

Frequency-selective electrokinetic enrichment of biomolecules in physiological media based on electrical double-layer polarization

et al. 2017

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Proteomic biomarkers of interest to the early diagnosis of diseases and infections are present at trace levels versus interfering species. Hence, their selective enrichment is needed within bio-assays for speeding binding kinetics with receptors and for reducing signal interferences. While DC fields can separate biomolecules based on their electrokinetic mobilities, they are unable to selectively enrich biomarkers versus interfering species, which may possess like-charges. We present the utilization of AC electrokinetics to enable frequency-selective enrichment of nanocolloidal biomolecules, based on the characteristic time constant for polarization of their electrical double-layer, since surface conduction in their ion cloud depends on colloidal size, shape and surface charge. In this manner, using DC-offset AC fields, differences in frequency dispersion for negative dielectrophoresis are balanced against electrophoresis in a nanoslit channel to enable the selective enrichment of prostate specific antigen (PSA) versus anti-mouse immunoglobulin antibodies that cause signal interferences to immunoassays. Through coupling enrichment to capture by receptors on graphene-modified surfaces, we demonstrate the elimination of false positives caused by anti-mouse immunoglobulin antibodies to the PSA immunoassay.

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“…DEP has been proven as an adaptable mechanism to transportation, accumulation, separation and characterization of submicron bio-particles in microfluidic systems. The integration of DEP systems into the microfluidics provides the inexpensive, fast, highly sensitive, selective and label-free detection of bio-species [15][16][17][18][19][20][21][22][23].…”

Section: Dielectrophoresismentioning

confidence: 99%