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Ganjalizadeh V, Meena GG, Wall TA, Stott MA, Hawkins AR, Schmidt H. Fast custom wavelet analysis technique for single molecule detection and identification. Nat Commun 2022; 13:1035. [PMID: 35210454 DOI: 10.1038/s41467-022-28703-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 01/20/2022] [Indexed: 02/01/2023] Open
Abstract
Many sensors operate by detecting and identifying individual events in a time-dependent signal which is challenging if signals are weak and background noise is present. We introduce a powerful, fast, and robust signal analysis technique based on a massively parallel continuous wavelet transform (CWT) algorithm. The superiority of this approach is demonstrated with fluorescence signals from a chip-based, optofluidic single particle sensor. The technique is more accurate than simple peak-finding algorithms and several orders of magnitude faster than existing CWT methods, allowing for real-time data analysis during sensing for the first time. Performance is further increased by applying a custom wavelet to multi-peak signals as demonstrated using amplification-free detection of single bacterial DNAs. A 4x increase in detection rate, a 6x improved error rate, and the ability for extraction of experimental parameters are demonstrated. This cluster-based CWT analysis will enable high-performance, real-time sensing when signal-to-noise is hardware limited, for instance with low-cost sensors in point of care environments. The authors introduce an accurate, fast and efficient technique to analyze sensory data. They use a continuous wavelet transform concept to look for certain patterns in noisy raw data. The superiority of this approach is demonstrated with fluorescence signals from a chip-based, optofluidic single particle sensor.
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Meena GG, Wright JG, Hawkins AR, Schmidt H. Greatly Enhanced Single Particle Fluorescence Detection Using High Refractive Index Liquid-Core Waveguides. IEEE J Sel Top Quantum Electron 2021; 27:6900407. [PMID: 33994767 PMCID: PMC8117828 DOI: 10.1109/jstqe.2021.3055078] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
High sensitivity and easy integration with microfabrication techniques has made silicon photonics one of the leading technologies used to build biosensors for diagnostic applications. Here we introduce a new silicon dioxide based optofluidic platform having a planar solid-core (SC) waveguide orthogonally intersecting a liquid-core (LC) waveguide with high refractive index ZnI2 salt solution as core. This enables both more uniform collection of particle fluorescence by the core mode and its propagation to an off-chip detector. This approach results in ultra-high sensitivity performance, demonstrated by achieving 8X enhancement in signal-to-noise ratio, a 45x increase in detection efficiency, and a 100x lower detection limit of 80 aM of fluorescent nanobeads. This represents a key step towards an ultrasensitive biosensor system for analyzing pathogens at clinical concentrations.
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Affiliation(s)
| | - Joel G Wright
- Electrical and Computer Engineering Department, Brigham Young University, Provo, UT 84602 USA
| | - Aaron R Hawkins
- Electrical and Computer Engineering Department, Brigham Young University, Provo, UT 84602 USA
| | - Holger Schmidt
- School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064 USA
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Amin MN, Ganjalizadeh V, Hamblin M, Hawkins AR, Schmidt H. Free-Space Excitation of Optofluidic Devices for Pattern-Based Single Particle Detection. IEEE Photonics Technol Lett 2021; 33:884-887. [PMID: 34744399 PMCID: PMC8570589 DOI: 10.1109/lpt.2021.3069673] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Optofluidic sensors have enabled single molecule sensing using planar, waveguide dependent multi-spot fluorescence excitation. Here, we demonstrate a new approach to single-particle fluorescence sensing using free-space, top-down illumination of liquid-core antiresonant reflecting optical waveguide (ARROW) devices using two different multi-spot excitation techniques. First, the liquid core ARROW waveguide is excited with a focused beam through a slit pattern milled into an opaque aluminum film, showing comparable performance for single bead fluorescence detection as in-plane, multi-mode interference waveguide based excitation. The second top-down illumination technique images the spot pattern from a Y-splitter SiO2 waveguide chip directly onto the detection device for efficient power utilization and circumventing the need for an opaque cover, producing a further 2.7x improvement in signal-to-noise ratio. The two top-down approaches open up new possibilities for chip-based optical particle sensing with relaxed alignment tolerances.
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Affiliation(s)
- Md Nafiz Amin
- School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064 USA
| | - Vahid Ganjalizadeh
- School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064 USA
| | - Matt Hamblin
- ECEn Department, Brigham Young University, Provo, UT 84602 USA
| | - Aaron R Hawkins
- ECEn Department, Brigham Young University, Provo, UT 84602 USA
| | - Holger Schmidt
- School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064 USA
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Meena GG, Stambaugh AM, Ganjalizadeh V, Stott MA, Hawkins AR, Schmidt H. Ultrasensitive detection of SARS-CoV-2 RNA and antigen using single-molecule optofluidic chip. APL Photonics 2021; 6:066101. [PMID: 35693725 PMCID: PMC9186413 DOI: 10.1063/5.0049735] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Nucleic acids and proteins are the two most important target types used in molecular diagnostics. In many instances, simultaneous sensitive and accurate detection of both biomarkers from the same sample would be desirable, but standard detection methods are highly optimized for one type and not cross-compatible. Here, we report the simultaneous multiplexed detection of SARS-CoV-2 RNAs and antigens with single molecule sensitivity. Both analytes are isolated and labeled using a single bead-based solid-phase extraction protocol, followed by fluorescence detection on a multi-channel optofluidic waveguide chip. Direct amplification-free detection of both biomarkers from nasopharyngeal swab samples is demonstrated with single molecule detection sensitivity, opening the door for ultrasensitive dual-target analysis in infectious disease diagnosis, oncology, and other applications.
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Affiliation(s)
- G. G. Meena
- School of Engineering, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA
| | - A. M. Stambaugh
- School of Engineering, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA
| | - V. Ganjalizadeh
- School of Engineering, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA
| | - M. A. Stott
- Electrical and Computer Engineering Department, Brigham Young University, Provo, Utah 84602, USA
| | - A. R. Hawkins
- Electrical and Computer Engineering Department, Brigham Young University, Provo, Utah 84602, USA
| | - H. Schmidt
- School of Engineering, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA
- Author to whom correspondence should be addressed:. Telephone: 831-459-1482
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Wright JG, Amin MN, Meena GG, Schmidt H, Hawkins AR. Optofluidic Flow-Through Biosensor Sensitivity - Model and Experiment. J Lightwave Technol 2021; 39:3330-3340. [PMID: 34177078 PMCID: PMC8224397 DOI: 10.1109/jlt.2021.3061872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We present a model and simulation for predicting the detected signal of a fluorescence-based optical biosensor built from optofluidic waveguides. Typical applications include flow experiments to determine pathogen concentrations in a biological sample after tagging relevant DNA or RNA sequences. An overview of the biosensor geometry and fabrication processes is presented. The basis for the predictive model is also outlined. The model is then compared to experimental results for three different biosensor designs. The model is shown to have similar signal statistics as physical tests, illustrating utility as a pre-fabrication design tool and as a predictor of detection sensitivity.
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Affiliation(s)
- Joel G Wright
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT, 84602, USA
| | - Md Nafiz Amin
- School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Gopikrishnan G Meena
- School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Holger Schmidt
- School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Aaron R Hawkins
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT, 84602, USA
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Wright JG, Schmidt H, Hawkins AR. Effects of Post-Etch Microstructures on the Optical Transmittance of Silica Ridge Waveguides. J Lightwave Technol 2020; 38:6280-6285. [PMID: 33776196 PMCID: PMC7996403 DOI: 10.1109/jlt.2020.3012899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Silica waveguides are often etched by reactive ion etch (RIE) processes. These processes can leave residual topography that can increase optical loss. We investigated the relation between optical loss and various RIE etch. A wet etch step meant to remove microstructures was also considered and compared. Ridge waveguides were fabricated in plasma enhanced chemical vapor deposited films by three different RIE processes, each with a different gas composition, pressure setting, and applied power setting. Half of each set of waveguides were also subjected to a hydrofluoric acid (HF) solution. The waveguides were tested for optical transmission via the cutback method. The transmission vs waveguide length measurements were plotted to fit an exponential curve and the optical loss and measurement uncertainty for each waveguide set was calculated. Clear distinctions in optical loss were found between the different RIE processes. The HF treatment also has an effect, significantly reducing optical loss for two processes and increasing it for the third. Of the tested RIE processes, one can be suggested for silica waveguides. It results in the lowest optical loss and coincidently has the fastest etch rate.
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Affiliation(s)
- Joel G Wright
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT, 84602, USA
| | - Holger Schmidt
- School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064, USA
| | - Aaron R Hawkins
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT, 84602, USA
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Meena GG, Wall TA, Stott MA, Brown O, Robison R, Hawkins AR, Schmidt H. 7X multiplexed, optofluidic detection of nucleic acids for antibiotic-resistance bacterial screening. Opt Express 2020; 28:33019-33027. [PMID: 33114971 PMCID: PMC7679188 DOI: 10.1364/oe.402311] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Rapid and accurate diagnosis of bacterial infections resistant to multiple antibiotics requires development of new bio-sensors for differentiated detection of multiple targets. This work demonstrates 7x multiplexed detection for antibiotic-resistance bacterial screening on an optofluidic platform. We utilize spectrally multiplexed multi-spot excitation for simultaneous detection of nucleic acid strands corresponding to bacterial targets and resistance genes. This is enabled by multi-mode interference (MMI) waveguides integrated in an optofluidic device. We employ a combinatorial three-color labeling scheme for the nucleic acid assays to scale up their multiplexing capability to seven different nucleic acids, representing three species and four resistance genes.
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Affiliation(s)
- G. G. Meena
- School of Engineering, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA
| | - T. A. Wall
- Electrical and Computer Engineering Department, Brigham Young University, Provo, Utah 84602, USA
| | - M. A. Stott
- Electrical and Computer Engineering Department, Brigham Young University, Provo, Utah 84602, USA
| | - O. Brown
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah 84602, USA
| | - R. Robison
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, Utah 84602, USA
| | - A. R. Hawkins
- Electrical and Computer Engineering Department, Brigham Young University, Provo, Utah 84602, USA
| | - H. Schmidt
- School of Engineering, University of California, Santa Cruz, 1156 High Street, Santa Cruz, California 95064, USA
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Stott MA, Ganjalizadeh V, Meena G, McMurray J, Olsen M, Orfila M, Schmidt H, Hawkins AR. Buried Rib SiO 2 Multimode Interference Waveguides for Optofluidic Multiplexing. IEEE Photonics Technol Lett 2018; 30:1487-1490. [PMID: 30618484 PMCID: PMC6319872 DOI: 10.1109/lpt.2018.2858258] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Multimode interference (MMI) waveguides can be used to create wavelength-dependent spot patterns which enables simultaneous analyte detection on a single optofluidic chip, useful for disease diagnostics. The fidelity of such multi-spot patterns is important for high sensitivity and accurate target identification. Buried rib structures have been incorporated into these SiO2-based waveguides to improve environmental stability. Through experiments and simulation, this letter explores design parameters for a buried MMI rib waveguide based on anti-resonant reflecting optical waveguides in order to produce high-fidelity spot patterns. Optimal rib heights and widths are reported in the context of available microfabrication etch technology and performance for an optimized biosensor is shown.
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Affiliation(s)
- Matthew A Stott
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602 USA
| | - Vahid Ganjalizadeh
- School of Engineering, University of California at Santa Cruz, Santa Cruz, CA 95064 USA
| | - Gopikrishnan Meena
- School of Engineering, University of California at Santa Cruz, Santa Cruz, CA 95064 USA
| | - Johnny McMurray
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602 USA
| | - Maclain Olsen
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602 USA
| | - Marcos Orfila
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602 USA
| | - Holger Schmidt
- School of Engineering, University of California at Santa Cruz, Santa Cruz, CA 95064 USA
| | - Aaron R Hawkins
- Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT 84602 USA
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Knob R, Hanson RL, Tateoka OB, Wood RL, Guerrero-Arguero I, Robison RA, Pitt WG, Woolley AT. Sequence-specific sepsis-related DNA capture and fluorescent labeling in monoliths prepared by single-step photopolymerization in microfluidic devices. J Chromatogr A 2018; 1562:12-18. [PMID: 29859687 DOI: 10.1016/j.chroma.2018.05.042] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 05/16/2018] [Accepted: 05/20/2018] [Indexed: 02/08/2023]
Abstract
Fast determination of antibiotic resistance is crucial in selecting appropriate treatment for sepsis patients, but current methods based on culture are time consuming. We are developing a microfluidic platform with a monolithic column modified with oligonucleotides designed for sequence-specific capture of target DNA related to the Klebsiella pneumoniae carbapenemase (KPC) gene. We developed a novel single-step monolith fabrication method with an acrydite-modified capture oligonucleotide in the polymerization mixture, enabling fast monolith preparation in a microfluidic channel using UV photopolymerization. These prepared columns had a threefold higher capacity compared to monoliths prepared in a multistep process involving Schiff-base DNA attachment. Conditions for denaturing, capture and fluorescence labeling using hybridization probes were optimized with synthetic 90-mer oligonucleotides. These procedures were applied for extraction of a PCR amplicon from the KPC antibiotic resistance gene in bacterial lysate obtained from a blood sample spiked with E. coli. The results showed similar eluted peak areas for KPC amplicon extracted from either hybridization buffer or bacterial lysate. Selective extraction of the KPC DNA was verified by real time PCR on eluted fractions. These results show great promise for application in an integrated microfluidic diagnostic system that combines upstream blood sample preparation and downstream single-molecule counting detection.
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Affiliation(s)
- Radim Knob
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, United States
| | - Robert L Hanson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, United States
| | - Olivia B Tateoka
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602, United States
| | - Ryan L Wood
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, United States
| | - Israel Guerrero-Arguero
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602, United States
| | - Richard A Robison
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT 84602, United States
| | - William G Pitt
- Department of Chemical Engineering, Brigham Young University, Provo, UT 84602, United States
| | - Adam T Woolley
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, United States.
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