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Reddy NN, Panda DK. Nanowire gate all around-TFET-based biosensor by considering ambipolar transport. APPLIED PHYSICS. A, MATERIALS SCIENCE & PROCESSING 2021; 127:682. [PMID: 34429569 PMCID: PMC8376115 DOI: 10.1007/s00339-021-04840-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
This work investigated the performance of overlapped gate-on-drain of a gate all around-tunnel field-effect transistor (GAA-TFET) biosensors by considering the dielectric modulated technique by immobilizing the targeted biomolecules in the cavity region curved under the overlapped gate-on-drain. The nanowire GAA-TFET device shows excellent controllability over the channel and reduces leakage current to a greater extent. Here, we tried to make the ambipolar nature of the TFET, an advantage for the biosensor by detecting the biomolecule using variation of ambipolar current of TFET. Due to structural arrangement, the nanocavity under the overlapped gate region suppresses the ambipolar drain current by increasing the dielectric constant of the targeted biomolecules. The device can show a variation of 102 and 103 amount of sensitivity for the variation of dielectric constant from 1 to 5 and, compared with the other TFET structure, the proposed overlapped gate-on-drain GAA-TFET biosensor shows higher sensitivity and low leakage with a highly controlled channel.
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Affiliation(s)
- N. Nagendra Reddy
- Microelectronics and VLSI Design Group, School of Electronics, VIT-AP University, Amaravati, Andhra Pradesh 522237 India
| | - Deepak Kumar Panda
- Microelectronics and VLSI Design Group, School of Electronics, VIT-AP University, Amaravati, Andhra Pradesh 522237 India
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2
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Solis-Marcano NE, Morales-Cruz M, Vega-Hernández G, Gómez-Moreno R, Binder C, Baerga-Ortiz A, Priest C, Cabrera CR. PCR-assisted impedimetric biosensor for colibactin-encoding pks genomic island detection in E. coli samples. Anal Bioanal Chem 2021; 413:4673-4680. [PMID: 34046698 PMCID: PMC8159250 DOI: 10.1007/s00216-021-03404-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 05/03/2021] [Accepted: 05/10/2021] [Indexed: 11/30/2022]
Abstract
A fast PCR-assisted impedimetric biosensor was developed for the selective detection of the clbN gene from the polyketide synthase (pks) genomic island in real Escherichia coli samples. This genomic island is responsible for the production of colibactin, a harmful genotoxin that has been associated with colorectal cancer. The experimental protocol consisted of immobilizing the designated forward primer onto an Au electrode surface to create the sensing probe, followed by PCR temperature cycling in blank, positive, and negative DNA controls. Target DNA identification was possible by monitoring changes in the system’s charge transfer resistance values (Rct) before and after PCR treatment through electrochemical impedance spectroscopy (EIS) analysis. Custom-made, flexible gold electrodes were fabricated using chemical etching optical lithography. A PCR cycle study determined the optimum conditions to be at 6 cycles providing fast results while maintaining a good sensitivity. EIS data for the DNA recognition process demonstrated the successful distinction between target interaction resulting in an increase in resistance to charge transfer (Rct) percentage change of 176% for the positive DNA control vs. 21% and 20% for the negative and non-DNA-containing controls, respectively. Results showed effective fabrication of a fast, PCR-based electrochemical biosensor for the detection of pks genomic island with a calculated limit of detection of 17 ng/μL.
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Affiliation(s)
- Nadja E Solis-Marcano
- Department of Chemistry, Molecular Sciences Research Center, University of Puerto Rico, Río Piedras Campus, San Juan, 00925-2537, Puerto Rico
| | - Myreisa Morales-Cruz
- Department of Chemistry, Molecular Sciences Research Center, University of Puerto Rico, Río Piedras Campus, San Juan, 00925-2537, Puerto Rico
| | - Gabriela Vega-Hernández
- Department of Chemistry, Molecular Sciences Research Center, University of Puerto Rico, Río Piedras Campus, San Juan, 00925-2537, Puerto Rico
| | - Ramón Gómez-Moreno
- Department of Biochemistry, Molecular Sciences Research Center, University of Puerto Rico, Medical Sciences Campus, San Juan, 00936-5067, Puerto Rico
| | - Claudia Binder
- Future Industries Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, Adelaide, South Australia, 5095, Australia
| | - Abel Baerga-Ortiz
- Department of Biochemistry, Molecular Sciences Research Center, University of Puerto Rico, Medical Sciences Campus, San Juan, 00936-5067, Puerto Rico
| | - Craig Priest
- Future Industries Institute, University of South Australia, Mawson Lakes Campus, Mawson Lakes, Adelaide, South Australia, 5095, Australia
| | - Carlos R Cabrera
- Department of Chemistry, Molecular Sciences Research Center, University of Puerto Rico, Río Piedras Campus, San Juan, 00925-2537, Puerto Rico.
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3
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Park S, Nguyen DV, Kang L. Immobilized nanoneedle-like structures for intracellular delivery, biosensing and cellular surgery. Nanomedicine (Lond) 2021; 16:335-349. [PMID: 33533658 DOI: 10.2217/nnm-2020-0337] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The rapid advancements of nanotechnology over the recent years have reformed the methods used for treating human diseases. Nanostructures including nanoneedles, nanorods, nanowires, nanofibers and nanotubes have exhibited their potential roles in drug delivery, biosensing, cancer therapy, regenerative medicine and intracellular surgery. These high aspect ratio structures enhance targeted drug delivery with spatiotemporal control while also demonstrating their role as an efficient intracellular biosensor with minimal invasiveness. This review discusses the history and emergence of these nanostructures and their fabrication methods. This review also provides an overview of the different applications of nanoneedle systems, further highlighting the importance of greater investigation into these nanostructures for future medicine.
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Affiliation(s)
- Sol Park
- School of Pharmacy, Faculty of Medicine & Health, University of Sydney, NSW 2006, Australia
| | - Duc-Viet Nguyen
- Nusmetics Pte. Ltd, i4 building, 3 Research Link, Singapore 117602, Republic of Singapore
| | - Lifeng Kang
- School of Pharmacy, Faculty of Medicine & Health, University of Sydney, NSW 2006, Australia
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4
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Joshi K, Velasco V, Esfandyarpour R. A Low-Cost, Disposable and Portable Inkjet-Printed Biochip for the Developing World. SENSORS 2020; 20:s20123593. [PMID: 32630509 PMCID: PMC7348740 DOI: 10.3390/s20123593] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/15/2020] [Accepted: 06/19/2020] [Indexed: 12/31/2022]
Abstract
Electrowetting on dielectric-based digital microfluidic platforms (EWOD-DMF) have a potential to impact point-of-care diagnostics. Conventionally, EWOD-DMF platforms are manufactured in cleanrooms by expert technicians using costly and time consuming micro-nanofabrication processes such as optical lithography, depositions and etching. However, such high-end microfabrication facilities are extremely challenging to establish in resource-poor and low-income countries, due to their high capital investment and operating costs. This makes the fabrication of EWOD-DMF platforms extremely challenging in low-income countries, where such platforms are most needed for many applications such as point-of-care testing applications. To address this challenge, we present a low-cost and simple fabrication procedure for EWOD-DMF electrode arrays, which can be performed anywhere with a commercial office inkjet printer without the need of expensive cleanroom facilities. We demonstrate the utility of our platform to move and mix droplets of different reagents and physiologically conductive buffers, thereby showing its capability to potentially perform a variety of biochemical assays. By combining our low-cost, inkjet-printed EWOD-DMF platform with smartphone imaging technology and a compact control system for droplet manipulation, we also demonstrate a portable and hand-held device which can be programmed to potentially perform a variety of biochemical assays.
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Affiliation(s)
- Kushal Joshi
- Department of Biomedical Engineering, University of California, Irvine, CA 92697, USA;
| | - Vanessa Velasco
- Biochemistry Department, Stanford University, Palo Alto, CA 92697, USA;
| | - Rahim Esfandyarpour
- Department of Biomedical Engineering, University of California, Irvine, CA 92697, USA;
- Department of Electrical Engineering, University of California, Irvine, CA 92697, USA
- Henry Samueli School of Engineering, University of California, Irvine, CA 92697, USA
- Correspondence:
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5
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Esfandyarpour R, Kashi A, Nemat-Gorgani M, Wilhelmy J, Davis RW. A nanoelectronics-blood-based diagnostic biomarker for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Proc Natl Acad Sci U S A 2019; 116:10250-10257. [PMID: 31036648 PMCID: PMC6535016 DOI: 10.1073/pnas.1901274116] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
There is not currently a well-established, if any, biological test to diagnose myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). The molecular aberrations observed in numerous studies of ME/CFS blood cells offer the opportunity to develop a diagnostic assay from blood samples. Here we developed a nanoelectronics assay designed as an ultrasensitive assay capable of directly measuring biomolecular interactions in real time, at low cost, and in a multiplex format. To pursue the goal of developing a reliable biomarker for ME/CFS and to demonstrate the utility of our platform for point-of-care diagnostics, we validated the array by testing patients with moderate to severe ME/CFS patients and healthy controls. The ME/CFS samples' response to the hyperosmotic stressor observed as a unique characteristic of the impedance pattern and dramatically different from the response observed among the control samples. We believe the observed robust impedance modulation difference of the samples in response to hyperosmotic stress can potentially provide us with a unique indicator of ME/CFS. Moreover, using supervised machine learning algorithms, we developed a classifier for ME/CFS patients capable of identifying new patients, required for a robust diagnostic tool.
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Affiliation(s)
- R Esfandyarpour
- Department of Electrical Engineering and Computer Science, University of California, Irvine, CA 92697;
| | - A Kashi
- Stanford Genome Technology Center, Stanford University, Stanford, CA 94304
| | - M Nemat-Gorgani
- Stanford Genome Technology Center, Stanford University, Stanford, CA 94304
- Department of Biochemistry, School of Medicine, Stanford University, Stanford, CA 94304
| | - J Wilhelmy
- Department of Biochemistry, School of Medicine, Stanford University, Stanford, CA 94304
| | - R W Davis
- Stanford Genome Technology Center, Stanford University, Stanford, CA 94304;
- Department of Biochemistry, School of Medicine, Stanford University, Stanford, CA 94304
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Alkayal NS, Hussein MA. Photocatalytic Degradation of Atrazine under Visible Light Using Novel Ag@Mg 4Ta 2O 9 Nanocomposites. Sci Rep 2019; 9:7470. [PMID: 31097751 PMCID: PMC6522532 DOI: 10.1038/s41598-019-43915-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 04/30/2019] [Indexed: 11/23/2022] Open
Abstract
In this work, a novel as well as an efficient photocatalyst based Ag@Mg4Ta2O9 nanoparticles have been prepared for the photocatalytic degradation of atrazine using the hydrothermal technique. In order to measure the chemical composition as well as the phase of the novel nanoparticles, different characterization techniques were applied to confirm their structures. Furthermore, the percent of Ag in the Ag@Mg4Ta2O9 nanoparticles has been investigated on the properties of Mg4Ta2O9 (physical and chemical). The phase of new Ag@Mg4Ta2O9 was confirmed via XRD data comparing with pure Mg4Ta2O9 phase. The images of the morphologies for all samples were studied using TEM with pore size distribution around 24 nm for 2.0 wt.% Ag@Mg4Ta2O9 nanocomposite. The new Ag@Mg4Ta2O9 nanoparticles have been applied for atrazine degradation using photocatalytic method. Due to the high BET surface area and low band gap, the nanoparticles with 2.0 wt.% of Ag@Mg4Ta2O9 display the best photocatalyst efficiency for atrazine degradation. Moreover, the application and the limitation of the photodegradation process were estimated. Different conditions effect on atrazine degradation such as dosages of photocatalyst and concentration of atrazine were investigated. The ability of 2.0 wt.% Ag@Mg4Ta2O9 for atrazine degradation was reused for many times with the same efficiency.
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Affiliation(s)
- Nazeeha S Alkayal
- Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia
| | - Mahmoud A Hussein
- Chemistry Department, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah, 21589, Saudi Arabia.
- Chemistry Department, Faculty of Science, Assiut University, Assiut, 71516, Egypt.
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7
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Novel Pd/ZnWO4 nanocomposite materials for photocatalytic degradation of atrazine. APPLIED NANOSCIENCE 2018. [DOI: 10.1007/s13204-018-0694-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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8
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Nanostructured Tip-Shaped Biosensors: Application of Six Sigma Approach for Enhanced Manufacturing. SENSORS 2016; 17:s17010017. [PMID: 28025540 PMCID: PMC5298590 DOI: 10.3390/s17010017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 12/10/2016] [Accepted: 12/20/2016] [Indexed: 11/16/2022]
Abstract
Nanostructured tip-shaped biosensors have drawn attention for biomolecule detection as they are promising for highly sensitive and specific detection of a target analyte. Using a nanostructured tip, the sensitivity is increased to identify individual molecules because of the high aspect ratio structure. Various detection methods, such as electrochemistry, fluorescence microcopy, and Raman spectroscopy, have been attempted to enhance the sensitivity and the specificity. Due to the confined path of electrons, electrochemical measurement using a nanotip enables the detection of single molecules. When an electric field is combined with capillary action and fluid flow, target molecules can be effectively concentrated onto a nanotip surface for detection. To enhance the concentration efficacy, a dendritic nanotip rather than a single tip could be used to detect target analytes, such as nanoparticles, cells, and DNA. However, reproducible fabrication with relation to specific detection remains a challenge due to the instability of a manufacturing method, resulting in inconsistent shape. In this paper, nanostructured biosensors are reviewed with our experimental results using dendritic nanotips for sequence specific detection of DNA. By the aid of the Six Sigma approach, the fabrication yield of dendritic nanotips increases from 20.0% to 86.6%. Using the nanotips, DNA is concentrated and detected in a sequence specific way with the detection limit equivalent to 1000 CFU/mL. The pros and cons of a nanotip biosensor are evaluated in conjunction with future prospects.
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9
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Modeling of Integrated Nanoneedle-Microfluidic System for Single Cell Temperature Measurement. APPLIED SCIENCES-BASEL 2016. [DOI: 10.3390/app6120339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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10
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Horizontally Aligned Carbon Nanotube Based Biosensors for Protein Detection. Bioengineering (Basel) 2016; 3:bioengineering3040023. [PMID: 28952585 PMCID: PMC5597266 DOI: 10.3390/bioengineering3040023] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/20/2016] [Accepted: 09/25/2016] [Indexed: 12/17/2022] Open
Abstract
A novel horizontally aligned single-walled carbon nanotube (CNT) Field Effect Transistor (FET)-based biosensing platform for real-time and sensitive protein detections is proposed. Aligned nanotubes were synthesized on quartz substrate using catalyst contact stamping, surface-guided morphological growth and chemical vapor deposition gas-guided growth methods. Real-time detection of prostate-specific antigen (PSA) using as-prepared FET biosensors was demonstrated. The kinetic measurements of the biosensor revealed that the drain current (Id) decreased exponentially as the concentration of PSA increased, indicating that the proposed FET sensor is capable of quantitative protein detection within a detection window of up to 1 µM. The limit of detection (LOD) achieved by the proposed platform was demonstrated to be 84 pM, which is lower than the clinically relevant level (133 pM) of PSA in blood. Additionally, the reported aligned CNT biosensor is a uniform sensing platform that could be extended to real-time detections of various biomarkers.
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11
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Emaminejad S, Paik KH, Tabard-Cossa V, Javanmard M. Portable Cytometry Using Microscale Electronic Sensing. SENSORS AND ACTUATORS. B, CHEMICAL 2016; 224:275-281. [PMID: 27647950 PMCID: PMC5026313 DOI: 10.1016/j.snb.2015.08.118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In this manuscript, we present three different micro-impedance sensing architectures for electronic counting of cells and beads. The first method of sensing is based on using an open circuit sensing electrode integrated in a micro-pore, which measures the shift in potential as a micron-sized particle passes through. Our micro-pore, based on a funnel shaped microchannel, was fabricated in PDMS and was bound covalently to a glass substrate patterned with a gold open circuit electrode. The amplification circuitry was integrated onto a battery-powered custom printed circuit board. The second method is based on a three electrode differential measurement, which opens up the potential of using signal processing techniques to increase signal to noise ratio post measurement. The third architecture uses a contactless sensing approach, which significantly minimizes the cost of the consumable component of the impedance cytometer. We demonstrated proof of concept for the three sensing architectures by measuring the detected signal due to the passage of micron sized beads through the pore.
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Affiliation(s)
- Sam Emaminejad
- Electrical Engineering and Computer Science Department, University of California Berkeley, Berkeley, CA, USA; School of Medicine, Stanford University, Stanford, CA, USA
| | - Kee-Hyun Paik
- School of Medicine, Stanford University, Stanford, CA, USA
| | | | - Mehdi Javanmard
- Electrical and Computer Engineering Department, Rutgers University, Piscataway, NJ, USA
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12
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Lead-Free Piezoelectric Diaphragm Biosensors Based on Micro-Machining Technology and Chemical Solution Deposition. SENSORS 2016; 16:s16010069. [PMID: 26771617 PMCID: PMC4732102 DOI: 10.3390/s16010069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2015] [Revised: 12/22/2015] [Accepted: 12/31/2015] [Indexed: 12/04/2022]
Abstract
In this paper, we present a new approach to the fabrication of integrated silicon-based piezoelectric diaphragm-type biosensors by using sodium potassium niobate-silver niobate (0.82KNN-0.18AN) composite lead-free thin film as the piezoelectric layer. The piezoelectric diaphragms were designed and fabricated by micro-machining technology and chemical solution deposition. The fabricated device was very sensitive to the mass changes caused by various targets attached on the surface of diaphragm. The measured mass sensitivity value was about 931 Hz/μg. Its good performance shows that the piezoelectric diaphragm biosensor can be used as a cost-effective platform for nucleic acid testing.
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13
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Label and Label-Free Detection Techniques for Protein Microarrays. MICROARRAYS 2015; 4:228-44. [PMID: 27600222 PMCID: PMC4996399 DOI: 10.3390/microarrays4020228] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 04/10/2015] [Accepted: 04/17/2015] [Indexed: 02/02/2023]
Abstract
Protein microarray technology has gone through numerous innovative developments in recent decades. In this review, we focus on the development of protein detection methods embedded in the technology. Early microarrays utilized useful chromophores and versatile biochemical techniques dominated by high-throughput illumination. Recently, the realization of label-free techniques has been greatly advanced by the combination of knowledge in material sciences, computational design and nanofabrication. These rapidly advancing techniques aim to provide data without the intervention of label molecules. Here, we present a brief overview of this remarkable innovation from the perspectives of label and label-free techniques in transducing nano-biological events.
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Rohani A, Varhue W, Su YH, Swami NS. Quantifying spatio-temporal dynamics of biomarker pre-concentration and depletion in microfluidic systems by intensity threshold analysis. BIOMICROFLUIDICS 2014; 8:052009. [PMID: 25538800 PMCID: PMC4222295 DOI: 10.1063/1.4897283] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/25/2014] [Indexed: 05/05/2023]
Abstract
Microfluidic systems are commonly applied towards pre-concentration of biomarkers for enhancing detection sensitivity. Quantitative information on the spatial and temporal dynamics of pre-concentration, such as its position, extent, and time evolution are essential towards sensor design for coupling pre-concentration to detection. Current quantification methodologies are based on the time evolution of fluorescence signals from biomarkers within a statically defined region of interest, which does not offer information on the spatial dynamics of pre-concentration and leads to significant errors when the pre-concentration zone is delocalized or exhibits wide variations in size, shape, and position over time under the force field. We present a dynamic methodology for quantifying the region of interest by using a statistical description of particle distribution across the device geometry to determine the intensity thresholds for particle pre-concentration. This method is applied to study the delocalized pre-concentration dynamics under an electrokinetic force balance driven by negative dielectrophoresis, for aligning the pre-concentration and detection regions of neuropeptide Y, and for quantifying the polarizability dispersion of silica nano-colloids with frequency of the force field. We envision the application of this automated methodology on data from 2D images and 3D Z-stacks for quantifying pre-concentration dynamics over delocalized regions as a function of the force field.
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Affiliation(s)
- Ali Rohani
- Electrical and Computer Engineering, University of Virginia , Charlottesville, Virginia 22904, USA
| | - Walter Varhue
- Electrical and Computer Engineering, University of Virginia , Charlottesville, Virginia 22904, USA
| | - Yi-Hsuan Su
- Electrical and Computer Engineering, University of Virginia , Charlottesville, Virginia 22904, USA
| | - Nathan S Swami
- Electrical and Computer Engineering, University of Virginia , Charlottesville, Virginia 22904, USA
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15
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Emaminejad S, Dutton RW, Davis RW, Javanmard M. Multiplexed actuation using ultra dielectrophoresis for proteomics applications: a comprehensive electrical and electrothermal design methodology. LAB ON A CHIP 2014; 14:2105-14. [PMID: 24801800 PMCID: PMC4097078 DOI: 10.1039/c4lc00036f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
In this work, we present a methodological approach to analyze an enhanced dielectrophoresis (DEP) system from both a circuit analysis and electrothermal view points. In our developed model, we have taken into account various phenomena and constraints such as voltage degradation (due to the presence of the protecting oxide layer), oxide breakdown, instrumentation limitations, and thermal effects. The results from this analysis are applicable generally to a wide variety of geometries and high voltage microsystems. Here, these design guidelines were applied to develop a robust electronic actuation system to perform a multiplexed bead-based protein assay. To carry out the multiplexed functionality, along a single microfluidic channel, an array of proteins is patterned, where each element is targeting a specific secondary protein coated on micron-sized beads in the subsequently introduced sample solution. Below each element of the array, we have a pair of addressable interdigitated electrodes. By selectively applying voltage at the terminals of each interdigitated electrode pair, the enhanced DEP, or equivalently 'ultra'-DEP (uDEP) force detaches protein-bound beads from each element of the array, one by one, without disturbing the bound beads in the neighboring regions. The detached beads can be quantified optically or electrically downstream. For proof of concept, we illustrated 16-plex actuation capability of our device to elute micron-sized beads that are bound to the surface through anti-IgG and IgG interaction which is on the same order of magnitude in strength as typical antibody-antigen interactions. In addition to its application in multiplexed protein analysis, our platform can be potentially utilized to statistically characterize the strength profile of biological bonds, since the multiplexed format allows for high throughput force spectroscopy using the array of uDEP devices, under the same buffer and assay preparation conditions.
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Affiliation(s)
- Sam Emaminejad
- Dept. of Electrical Engineering, Stanford University, Stanford, CA
- School of Medicine, Stanford University, Stanford, CA, USA
- Stanford Genome Technology Center, Palo Alto, CA
| | - Robert W. Dutton
- Dept. of Electrical Engineering, Stanford University, Stanford, CA
| | - Ronald W. Davis
- School of Medicine, Stanford University, Stanford, CA, USA
- Stanford Genome Technology Center, Palo Alto, CA
| | - Mehdi Javanmard
- School of Medicine, Stanford University, Stanford, CA, USA
- Stanford Genome Technology Center, Palo Alto, CA
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16
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Javanmard M, Emaminejad S, Gupta C, Provine J, Davis R, Howe R. Depletion of cells and abundant proteins from biological samples by enhanced dielectrophoresis. SENSORS AND ACTUATORS. B, CHEMICAL 2014; 193:918-924. [PMID: 26924893 PMCID: PMC4765371 DOI: 10.1016/j.snb.2013.11.100] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Platforms that are sensitive and specific enough to assay low-abundance protein biomarkers, in a high throughput multiplex format, within a complex biological fluid specimen, are necessary to enable protein biomarker based diagnostics for diseases such as cancer. The signal from an assay for a low-abundance protein biomarker in a biological fluid sample like blood is typically buried in a background that arises from the presence of blood cells and from high-abundance proteins that make up 90% of the assayed protein mass. We present an automated on-chip platform for the depletion of cells and highly abundant serum proteins in blood. Our platform consists of two components, the first of which is a microfluidic mixer that mixes beads containing antibodies against the highly abundant proteins in the whole blood. This complex mixture (consisting of beads, cells, and serum proteins) is then injected into the second component of our microfluidic platform, which comprises a filter trench to capture all the cells and the beads. The size-based trapping of the cells and beads into the filter trench is significantly enhanced by leveraging additional negative dielectrophoretic forces to push the micron sized particles (cells and beads which have captured the highly abundant proteins) down into the trench, allowing the serum proteins of lower abundance to flow through. In general, dielectrophoresis using bare electrodes is incapable of producing forces beyond the low piconewton range that tend to be insufficient for separation applications. However, by using electrodes passivated with atomic layer deposition, we demonstrate the application of enhanced negative DEP electrodes together with size-based flltration induced by the filter trench, to deplete 100% of the micron sized particles in the mixture.
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Affiliation(s)
- M. Javanmard
- Stanford Genome Technology Center, Stanford University, Stanford, CA, USA
| | - S. Emaminejad
- Stanford Genome Technology Center, Stanford University, Stanford, CA, USA
- Electrical Engineering Department, Stanford University, Stanford, CA, USA
| | - C. Gupta
- Electrical Engineering Department, Stanford University, Stanford, CA, USA
| | - J. Provine
- Electrical Engineering Department, Stanford University, Stanford, CA, USA
| | - R.W. Davis
- Stanford Genome Technology Center, Stanford University, Stanford, CA, USA
| | - R.T. Howe
- Electrical Engineering Department, Stanford University, Stanford, CA, USA
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17
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Mok J, Mindrinos MN, Davis RW, Javanmard M. Digital microfluidic assay for protein detection. Proc Natl Acad Sci U S A 2014; 111:2110-5. [PMID: 24449893 PMCID: PMC3926080 DOI: 10.1073/pnas.1323998111] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Global studies of the human proteome have revealed a plethora of putative protein biomarkers. However, their application for early disease detection remains at a standstill without suitable methods to realize their utility in the clinical setting. There thus continues to be tremendous interest in developing new technology for sensitive protein detection that is both low in cost and carries a small footprint to be able to be used at the point of care. The current gold standard method for protein biomarker detection is the ELISA, which measures protein abundance using bulky fluorescent scanners that lack portability. Here, we present a digital microfluidic platform for protein biomarker detection that is low in cost compared with standard optical detection methods, without any compromise in sensitivity. This platform furthermore makes use of simple electronics, enabling its translation into a portable handheld device, and has been developed in a manner that can easily be adapted to assay different types of proteomic biomarkers. We demonstrate its utility in quantifying not only protein abundance, but also activity. Interleukin-6 abundance could be assayed from concentrations as low as 50 pM (an order of magnitude lower than that detectable by a comparable laboratory designed ELISA) using less than 5 μL of sample, and Abelson tyrosine kinase activity was detectable in samples containing 100 pM of kinase.
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Affiliation(s)
- Janine Mok
- Stanford Genome Technology Center, Department of Biochemistry, Stanford University, Palo Alto, CA 94304
| | - Michael N. Mindrinos
- Stanford Genome Technology Center, Department of Biochemistry, Stanford University, Palo Alto, CA 94304
| | - Ronald W. Davis
- Stanford Genome Technology Center, Department of Biochemistry, Stanford University, Palo Alto, CA 94304
| | - Mehdi Javanmard
- Stanford Genome Technology Center, Department of Biochemistry, Stanford University, Palo Alto, CA 94304
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Esfandyarpour R, Javanmard M, Koochak Z, Harris JS, Davis RW. Nanoelectronic impedance detection of target cells. Biotechnol Bioeng 2013; 111:1161-9. [PMID: 24338648 DOI: 10.1002/bit.25171] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 12/02/2013] [Accepted: 12/05/2013] [Indexed: 11/07/2022]
Abstract
Detection of cells is typically performed using optical fluorescence based techniques such as flow cytometry. Here we present the impedance detection of target cells using a nanoelectronic probe we have developed, which we refer to as the nanoneedle biosensor. The nanoneedle consists of a thin film conducting electrode layer at the bottom, an insulative oxide layer above, another conductive electrode layer above, and a protective oxide above. The electrical impedance is measured between the two electrode layers. Cells captured on the surface of the nanoneedle tip results in a decrease in the impedance across the sensing electrodes. The basic mechanisms behind the electrical response of cells in solution under an applied alternating electrical field stems from modulation of the relative permittivity at the interface. In this paper we discuss, the circuit model, the nanofabrication, and the testing and characterization of the sensor. We demonstrate proof of concept for detection of yeast cells with specificity. We envision the sensor presented in this paper to be combined with microfluidic pre-concentration technologies to develop low cost point-of-care diagnostic assays for the clinical setting.
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Affiliation(s)
- Rahim Esfandyarpour
- Center for Integrated Systems, Department of Electrical Engineering, Stanford University, Stanford, California; Stanford Genome Technology Center, 855 California Ave., Palo Alto, California, 94304.
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