High-Speed Interferometric Detection of Label-Free Immunoassays on the Biological Compact Disc

Abstract Background: We describe a direct-detection immunoassay that uses high-speed optical interferometry on a biological compact disc (BioCD). Methods: We fabricated phase-contrast BioCDs from 100-mm diameter 1.1-mm thick borosilicate glass disks coated with a 10-layer dielectric stack of Ta2O5/SiO2 that serves as a mirror with a center wavelength at 635 nm. The final layer is a λ/4 layer of SiO2 onto which protein patterns are immobilized through several different chemical approaches. Protein on the disc is scanned by a focused laser spot as the disc spins. Interaction of the light with the protein provides both a phase-modulated signal and a local reference that are combined interferometrically to convert phase into intensity. A periodic pattern of protein on the spinning disc produces an intensity modulation as a function of time that is proportional to the surface-bound mass. The binding of antigen or antibodies is detected directly, without labels, by a change in the interferometric intensity. The technique is demonstrated with a reverse assay of immobilized rabbit and mouse IgG antigen incubated against anti-IgG antibody in a casein buffer. Results: The signal increased with increased concentration of analyte. The current embodiment detected a concentration of 100 ng/L when averaged over ∼3000 100-micron-diameter protein spots. Conclusions: High-speed interferometric detection of label-free protein assays on a rapidly spinning BioCD is a high-sensitivity approach that is amenable to scaling up to many analytes.

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Testing and performance of high-speed high-sensitivity direct-detection receivers

10.1117/12.135405 ◽

1992 ◽

Author(s):

David R. Patterson

Keyword(s):

High Speed ◽

Direct Detection ◽

High Sensitivity ◽

And Performance

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Rapid Label-free Protein Detection Arrays on Coated Silicon Wafers

MRS Proceedings ◽

10.1557/proc-0951-e09-07 ◽

2006 ◽

Vol 951 ◽

Author(s):

Christopher C. Striemer ◽

Charles R. Mace ◽

Benjamin L. Miller

Keyword(s):

Dynamic Range ◽

Direct Detection ◽

Protein Detection ◽

Ccd Camera ◽

High Sensitivity ◽

High Dynamic Range ◽

Solution Concentration ◽

Label Free ◽

Probe Molecules ◽

Target Binding

ABSTRACTWe are developing label-free Arrayed Imaging Reflectometry (AIR) for rapid and multiplexed protein detection. AIR is based on the high dynamic range in reflected optical intensity near a point of zero reflectance on an antireflection coated substrate. The reflectance is therefore highly sensitive to changes in film thickness, allowing direct detection of molecular binding when appropriate probe molecules are immobilized on the surface. The simplest implementation of AIR uses a 633 nm HeNe laser and a silicon wafer substrate coated with ∼1400 Å of SiO2. This system has a reflectance zero for s-polarized HeNe light incident at ∼70°. This interference film is then functionalized with probe molecules designed to bind to a specific target, and this binding can be detected with high sensitivity in the reflectance signal. By expanding the laser beam and collecting the reflected signal with a CCD camera, large arrays of detection spots can be imaged simultaneously. Spot intensity increases relative to the amount of target binding and the target solution concentration can then be calculated. We have demonstrated the detection of the Enteropathogenic E Coli membrane protein Intimin at levels below 10 pM using receptor molecule Tir as a probe, and are currently evaluating various clinical targets using more common antibody probes.

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Photonic Time-Stretch Spectroscopy for Multiplex Stimulated Raman Scattering

EPJ Web of Conferences ◽

10.1051/epjconf/201920503003 ◽

2019 ◽

Vol 205 ◽

pp. 03003

Author(s):

Francesco Saltarelli ◽

Vikas Kumar ◽

Daniele Viola ◽

Francesco Crisafi ◽

Fabrizio Preda ◽

...

Keyword(s):

Raman Scattering ◽

High Speed ◽

Materials Science ◽

Stimulated Raman Scattering ◽

High Sensitivity ◽

Single Shot ◽

Label Free ◽

Raman Scattering Spectroscopy ◽

Novel Approach ◽

Stimulated Raman

Stimulated Raman scattering spectroscopy enables label-free molecular identification, but its broadband implementation is technically challenging. We experimentally demonstrate a novel approach to multiplex stimulated Raman scattering based on photonic time stretch. A telecom fiber stretches the broadband femtosecond Stokes pulse after the sample to ∼15ns, mapping its spectrum in time. The signal is sampled through a fast oscilloscope, providing single-shot spectra at 80-kHz rate. We demonstrate high sensitivity in detecting the Raman vibrational modes of various samples over the entire high-frequency C-H stretching region. Our results pave the way to high-speed broadband vibrational imaging for materials science and biophotonics.

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Simple Label-Free Electrochemical Immunosensor in a Microchamber for Detecting Newcastle Disease Virus

Journal of Nanomaterials ◽

10.1155/2019/3835609 ◽

2019 ◽

Vol 2019 ◽

pp. 1-9 ◽

Cited By ~ 2

Author(s):

Luyen Thi Tran ◽

Thinh Quang Tran ◽

Ha Phu Ho ◽

Xuan Thi Chu ◽

Tuan Anh Mai

Keyword(s):

Newcastle Disease Virus ◽

Disease Virus ◽

Newcastle Disease ◽

Direct Detection ◽

High Sensitivity ◽

Field Measurements ◽

Egg Yolk ◽

Extraction Process ◽

Electrochemical Immunosensor ◽

Label Free

In this study, a simple, label-free, electrochemical immunosensor system, including a three-electrode transducer and a microchamber, was designed, fabricated, and integrated with focus toward the detection of Newcastle disease virus (NDV). The chicken egg yolk antibodies (IgY) against NDV were used as the biological recognition element, replacing purified IgG antibodies that require a complex extraction process and time-consuming. The IgY against NDV was immobilized on the sensor surface using PrA/GA and SAM/NHS approaches. The immunosensor showed high sensitivity with NDV concentrations ranging from 106 to 102 EID50/mL with good specificity, repeatability, and small standard deviations. Compared to traditional methods, the immunosensor with advantages such as simple fabrication, quick response, direct detection, and possibility for miniaturization by integrating the immunosensor with the microchamber is potential for applications in contamination studies and field measurements.

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A microfluidic device with integrated impedance detection for λ-DNA

MRS Proceedings ◽

10.1557/proc-773-n6.5 ◽

2003 ◽

Vol 773 ◽

Cited By ~ 1

Author(s):

Myung-Il Park ◽

Jonging Hong ◽

Dae Sung Yoon ◽

Chong-Ook Park ◽

Geunbae Im

Keyword(s):

Microfluidic Device ◽

Electrochemical Impedance ◽

Direct Detection ◽

Full Potential ◽

Label Free ◽

Buffer Solution ◽

Detection Systems ◽

Significant Difference ◽

Detection Of Biomolecules ◽

Impedance Magnitude

AbstractThe large optical detection systems that are typically utilized at present may not be able to reach their full potential as portable analysis tools. Accurate, early, and fast diagnosis for many diseases requires the direct detection of biomolecules such as DNA, proteins, and cells. In this research, a glass microchip with integrated microelectrodes has been fabricated, and the performance of electrochemical impedance detection was investigated for the biomolecules. We have used label-free λ-DNA as a sample biomolecule. By changing the distance between microelectrodes, the significant difference between DW and the TE buffer solution is obtained from the impedance-frequency measurements. In addition, the comparison for the impedance magnitude of DW, the TE buffer, and λ-DNA at the same distance was analyzed.

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Rapid Online Buffer Exchange: A Method for Screening of Proteins, Protein Complexes, and Cell Lysates by Native Mass Spectrometry

10.26434/chemrxiv.8792177 ◽

2019 ◽

Author(s):

Zachary VanAernum ◽

Florian Busch ◽

Benjamin J. Jones ◽

Mengxuan Jia ◽

Zibo Chen ◽

...

Keyword(s):

Mass Spectrometry ◽

High Speed ◽

Structural Information ◽

Protein Complexes ◽

High Sensitivity ◽

Native Mass Spectrometry ◽

Structural Features ◽

Consumer Products ◽

Cell Lysates ◽

Protein Expression And Purification

It is important to assess the identity and purity of proteins and protein complexes during and after protein purification to ensure that samples are of sufficient quality for further biochemical and structural characterization, as well as for use in consumer products, chemical processes, and therapeutics. Native mass spectrometry (nMS) has become an important tool in protein analysis due to its ability to retain non-covalent interactions during measurements, making it possible to obtain protein structural information with high sensitivity and at high speed. Interferences from the presence of non-volatiles are typically alleviated by offline buffer exchange, which is timeconsuming and difficult to automate. We provide a protocol for rapid online buffer exchange (OBE) nMS to directly screen structural features of pre-purified proteins, protein complexes, or clarified cell lysates. Information obtained by OBE nMS can be used for fast (<5 min) quality control and can further guide protein expression and purification optimization.

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The impact of inelastic self-interacting dark matter on the dark matter structure of a Milky Way halo

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa3315 ◽

2020 ◽

Author(s):

Kun Ting Eddie Chua ◽

Karia Dibert ◽

Mark Vogelsberger ◽

Jesús Zavala

Keyword(s):

Dark Matter ◽

High Speed ◽

Cold Dark Matter ◽

Milky Way ◽

Direct Detection ◽

Major Axis ◽

Inelastic Collisions ◽

Axis Ratio ◽

Lower Velocity ◽

The Impact

Abstract We study the effects of inelastic dark matter self-interactions on the internal structure of a simulated Milky Way (MW)-size halo. Self-interacting dark matter (SIDM) is an alternative to collisionless cold dark matter (CDM) which offers a unique solution to the problems encountered with CDM on sub-galactic scales. Although previous SIDM simulations have mainly considered elastic collisions, theoretical considerations motivate the existence of multi-state dark matter where transitions from the excited to the ground state are exothermic. In this work, we consider a self-interacting, two-state dark matter model with inelastic collisions, implemented in the Arepo code. We find that energy injection from inelastic self-interactions reduces the central density of the MW halo in a shorter timescale relative to the elastic scale, resulting in a larger core size. Inelastic collisions also isotropize the orbits, resulting in an overall lower velocity anisotropy for the inelastic MW halo. In the inner halo, the inelastic SIDM case (minor-to-major axis ratio s ≡ c/a ≈ 0.65) is more spherical than the CDM (s ≈ 0.4), but less spherical than the elastic SIDM case (s ≈ 0.75). The speed distribution f(v) of dark matter particles at the location of the Sun in the inelastic SIDM model shows a significant departure from the CDM model, with f(v) falling more steeply at high speeds. In addition, the velocity kicks imparted during inelastic collisions produce unbound high-speed particles with velocities up to 500 km s−1 throughout the halo. This implies that inelastic SIDM can potentially leave distinct signatures in direct detection experiments, relative to elastic SIDM and CDM.

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40 Gb/s High-speed mode-division multiplexing transmission employing NRZ modulation format

Journal of Optical Communications ◽

10.1515/joc-2019-0251 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Rabiu Imam Sabitu ◽

Nafizah Goriman Khan ◽

Amin Malekmohammadi

Keyword(s):

System Performance ◽

High Speed ◽

Direct Detection ◽

Signal To Noise Ratio ◽

Optical Signal ◽

Threshold Power ◽

Modulation Format ◽

Transmission Distance ◽

Mode Division Multiplexing ◽

Speed Mode

AbstractThis report examines the performance of a high-speed MDM transmission system supporting four nondegenerate spatial modes at 10 Gb/s. The analysis adopts the NRZ modulation format to evaluate the system performance in terms of a minimum power required (PN) and the nonlinear threshold power (PTH) at a BER of 10−9. The receiver sensitivity, optical signal-to-noise ratio, and the maximum transmission distance were investigated using the direct detection by employing a multimode erbium-doped amplifier (MM-EDFA). It was found that by properly optimizing the MM-EDFA, the system performance can significantly be improved.

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Integrating high-performing electrochemical transducers in lateral flow assay

Analytical and Bioanalytical Chemistry ◽

10.1007/s00216-021-03301-y ◽

2021 ◽

Author(s):

Antonia Perju ◽

Nongnoot Wongkaew

Keyword(s):

High Performance ◽

Point Of Care ◽

Low Cost ◽

High Sensitivity ◽

Lateral Flow ◽

Analytical Performance ◽

Label Free ◽

High Performing ◽

Lateral Flow Assays ◽

Electrochemical Transducers

AbstractLateral flow assays (LFAs) are the best-performing and best-known point-of-care tests worldwide. Over the last decade, they have experienced an increasing interest by researchers towards improving their analytical performance while maintaining their robust assay platform. Commercially, visual and optical detection strategies dominate, but it is especially the research on integrating electrochemical (EC) approaches that may have a chance to significantly improve an LFA’s performance that is needed in order to detect analytes reliably at lower concentrations than currently possible. In fact, EC-LFAs offer advantages in terms of quantitative determination, low-cost, high sensitivity, and even simple, label-free strategies. Here, the various configurations of EC-LFAs published are summarized and critically evaluated. In short, most of them rely on applying conventional transducers, e.g., screen-printed electrode, to ensure reliability of the assay, and additional advances are afforded by the beneficial features of nanomaterials. It is predicted that these will be further implemented in EC-LFAs as high-performance transducers. Considering the low cost of point-of-care devices, it becomes even more important to also identify strategies that efficiently integrate nanomaterials into EC-LFAs in a high-throughput manner while maintaining their favorable analytical performance.

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