Fabricating a UV-Vis and Raman Spectroscopy Immunoassay Platform

Hanson, Cynthia; Israelsen, Nathan D.; Sieverts, Michael; Vargis, Elizabeth

doi:10.3791/54795

Cited by 4 publications

(3 citation statements)

References 11 publications

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“…Raman spectra of trapped bacteria were collected using an in‐house‐built Raman microscope unit as described previously . The unit consisted of an inverted Nikon Eclipse TE2000‐S microscope (Melville, NY, USA), 785 nm single‐mode laser (Innovative Photonic Solutions, Monmouth, NJ, USA), and IsoPlane 160 spectrometer (Princeton Instruments, Trenton, NJ, USA) equipped with a 1200 g/mm grating, 750 nm blaze, and a Pixis‐400 CCD (Princeton Instruments).…”

Section: Methodsmentioning

confidence: 99%

Simultaneous isolation and label‐free identification of bacteria using contactless dielectrophoresis and Raman spectroscopy

et al. 2019

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The traditional bacterial identification method of growing colonies on agar plates can take several days to weeks to complete depending on the growth rate of the bacteria. Successfully decreasing this analysis time requires cell isolation followed by identification. One way to decrease analysis time is by combining dielectrophoresis (DEP), a common technique used for cell sorting and isolation, and Raman spectroscopy for cell identification. DEP‐Raman devices have been used for bacterial analysis, however, these devices have a number of drawbacks including sample heating, cell‐to‐electrode proximity that limits throughput and separation efficiency, electrode fouling, or inability to address sample debris. Presented here is a contactless DEP‐Raman device to simultaneously isolate and identify particles from a mixed sample while avoiding common drawbacks associated with other DEP designs. Using the device, a mixed sample of bacteria and 3 μm polystyrene spheres were isolated from each other and a Raman spectrum of the trapped bacteria was acquired, indicating the potential for cDEP‐Raman devices to decrease the analysis time of bacteria.

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Section: Methodsmentioning

confidence: 99%

Simultaneous isolation and label‐free identification of bacteria using contactless dielectrophoresis and Raman spectroscopy

et al. 2019

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“…Raman spectra were collected using an in-house built Raman microscope unit as described and used previously [ 18 , 19 ]. The unit consists of an inverted Nikon Eclipse TE2000-S (Melville, NY, USA), a 785 nm single-mode laser (Innovative Photonic Solutions, Monmouth, NJ, USA), an IsoPlane 160 spectrometer equipped with a 1200 g/mm grating (Princeton Instruments, Trenton, NJ, USA), and a Pixis-400 CCD (Princeton Instruments).…”

Section: Methodsmentioning

confidence: 99%

Alternative cDEP Design to Facilitate Cell Isolation for Identification by Raman Spectroscopy

Hanson

Vargis

2017

Sensors

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Dielectrophoresis (DEP) uses non-uniform electric fields to cause motion in particles due to the particles' intrinsic properties. As such, DEP is a well-suited label-free means for cell sorting. Of the various methods of implementing DEP, contactless dielectrophoresis (cDEP) is advantageous as it avoids common problems associated with DEP, such as electrode fouling and electrolysis. Unfortunately, cDEP devices can be difficult to fabricate, replicate, and reuse. In addition, the operating parameters are limited by the dielectric breakdown of polydimethylsiloxane (PDMS). This study presents an alternative way to fabricate a cDEP device allowing for higher operating voltages, improved replication, and the opportunity for analysis using Raman spectroscopy. In this device, channels were formed in fused silica rather than PDMS. The device successfully trapped 3.3 µm polystyrene spheres for analysis by Raman spectroscopy. The successful implementation indicates the potential to use cDEP to isolate and identify biological samples on a single device.

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“…Raman spectra of trapped bacteria were collected using an in-house-built Raman microscope unit as described and used previously [137,138]. The unit consists of an inverted Nikon Eclipse TE2000-S (Melville, NY, USA), a 785 nm single-mode laser (Innovative Photonic Solutions, Monmouth, NJ, USA), an IsoPlane 160 spectrometer equipped with a 1200 g/mm grating (Princeton Instruments, Trenton, NJ, USA), and a Pixis-400 CCD (Princeton Instruments).…”

Section: Methodsmentioning

confidence: 99%

The use of microfluidics and dielectrophoresis for separation, concentration, and identification of bacteria

et al. 2016

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Traditional bacterial analyses take one to two days under favorable conditions where the bulk of the time is spent waiting for bacteria to divide and grow until visual colonies can be observed for identification. In the case of bacteria with slow doubling times, this process can take weeks. This delay in analysis is unacceptable, especially in cases of life threatening diseases or emergencies. It is clear that in order to decrease the analysis time of the bacteria, the culturing and growth step must be circumvented. The goal of this research is to design, build, and test a device that could decrease the analysis time of bacteria using label-free methods of dielectrophoresis and Raman spectroscopy.Testing for device design was performed with clinical samples in mind, which consist of bacteria grown in a variety of environmental conditions (i.e. available food sources, growth stage, temperature, etc.) and accompanied by sample debris. Raman spectra of bacteria grown in varying media and metabolic stages were collected and analyzed. Results indicate that growth phase and media have an impact on Raman spectra iv and is distinguishable by linear discriminant analysis (LDA). Despite these spectral differences, it was found that LDA classification of closely related bacteria remains fairly high (90%) regardless of growth phase. Sample debris were also considered in device design and accommodated for by dielectrophoresis. Devices were built with the goal to isolate bacteria from a mixed sample and simultaneously acquire Raman spectra for identification.For this dissertation, a device was designed, built, and tested that incorporates dielectrophoresis for particle isolation and Raman spectroscopy for identification. The device was modeled in COMSOL to ensure that an appropriate electrical field gradient could be obtained to isolate bacteria from 5 µm diameter polystyrene spheres. The device was built and successfully trapped bacteria away from polystyrene spheres and Raman spectra of the bacteria were collected while trapped. These results indicate a clear potential for contactless dielectrophoresis-Raman devices to isolate and identify bacteria from sample debris, and thereby decrease the analysis time of bacteria. Typical bacterial analysis involves culturing and visualizing colonies on an array of agar plates. The growth patterns and colors among the array are used to identify the bacteria. For fast growing bacteria such as Escherichia coli, analysis will take one to two days. However, slow growing bacteria such as mycobacteria can take weeks to identify.In addition, there are some species of bacteria that are viable but nonculturable. This lengthy analysis time is unacceptable for life-threatening infections and emergency situations. It is clear that to decrease the analysis of the bacteria, the culturing and growth steps must be avoided. The goal of this research is to design, build, and test a device that could decrease the analysis time of bacteria.

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Fabricating a UV-Vis and Raman Spectroscopy Immunoassay Platform

Cited by 4 publications

References 11 publications

Simultaneous isolation and label‐free identification of bacteria using contactless dielectrophoresis and Raman spectroscopy

Simultaneous isolation and label‐free identification of bacteria using contactless dielectrophoresis and Raman spectroscopy

Alternative cDEP Design to Facilitate Cell Isolation for Identification by Raman Spectroscopy

The use of microfluidics and dielectrophoresis for separation, concentration, and identification of bacteria

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