Optoelectronic tweezers for medical diagnostics

Kremer, Clemens; Neale, Steven L.; Menachery, Anoop; Barrett, Mike; Cooper, Jonathan M.

doi:10.1117/12.903944

Cited by 4 publications

(8 citation statements)

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“…Figure 4A represent the average (n = 3) attachment percentage of T. brucei to the electrode at a given frequency. A theoretical DEP response of T. brucei, shown as the smooth red curve, was previously reported by Kremer et al [17] and overlaid over our results for comparison and discussed next. It can be clearly observed that the percentage of attachment in the experiments performed here was at least 50% and that a polarizing frequency of 750 kHz leads to the strongest positive DEP force and highest percent attachment, thereby providing the most potential to rapidly enrich the parasites in a specific location.…”

Section: Characterizing the Dielectrophoretic Response Of T Bruceimentioning

confidence: 52%

“…In fact, different DEP signatures have been reported for blood cells and parasites [12,15,16]. Of most relevance to the work presented here is the separation of T. brucei from RBCs demonstrated by Kremer et al using a light-induced DEP (LiDEP) setup [17], and the localization of T. brucei reported by Menachery et al using spiral gold electrodes and traveling-wave DEP (twDEP) [18]. As previously detailed by one of us, there are different techniques to implement the field gradient required for DEP [19].…”

Section: Introductionmentioning

confidence: 80%

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Highly Localized Enrichment of Trypanosoma brucei Parasites Using Dielectrophoresis

et al. 2020

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Human African trypanosomiasis (HAT), also known as sleeping sickness, is a vector-borne neglected tropical disease endemic to rural sub-Saharan Africa. Current methods of early detection in the affected rural communities generally begin with general screening using the card agglutination test for trypanosomiasis (CATT), a serological test. However, the gold standard for confirmation of trypanosomiasis remains the direct observation of the causative parasite, Trypanosoma brucei. Here, we present the use of dielectrophoresis (DEP) to enrich T. brucei parasites in specific locations to facilitate their identification in a future diagnostic assay. DEP refers to physical movement that can be selectively induced on the parasites when exposing them to electric field gradients of specific magnitude, phase and frequency. The long-term goal of our work is to use DEP to selectively trap and enrich T. brucei in specific locations while eluting all other cells in a sample. This would allow for a diagnostic test that enables the user to characterize the presence of parasites in specific locations determined a priori instead of relying on scanning a sample. In the work presented here, we report the characterization of the conditions that lead to high enrichment, 780% in 50 s, of the parasite in specific locations using an array of titanium microelectrodes.

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Section: Characterizing the Dielectrophoretic Response Of T Bruceimentioning

confidence: 52%

Section: Introductionmentioning

confidence: 80%

Highly Localized Enrichment of Trypanosoma brucei Parasites Using Dielectrophoresis

et al. 2020

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“…As such, we propose to integrate the detection platform described here with a number of microfluidic techniques currently being developed in our labs, such as droplet-based immunoassays 20 , detection of parasites/medical diagnostics 21 , and microdroplet sorting based on the SERRS spectra obtained from the microdroplets. As well as improving our ability to detect multiple species simultaneously by SERRS spectroscopy, we also aim to match the current state of the art in microdroplet detection, which will involve a much higher rate of droplet generation (and hence much lower acquisition times, and thus lower quality spectra/signal to noise ratios) and extremely high efficiency of droplet sorting 22 .…”

Section: Future Developmentsmentioning

confidence: 99%

Characterization of individual microdroplets by SERRS spectroscopy

et al. 2012

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Raman spectroscopy and its various derivatives continue to offer the analyst fast, powerful, non-invasive and nondestructive means by which to identify multiple analytes simultaneously and in real time. By virtue of the huge enhancements possible in Raman scattering, generated by both surface enhancement and the resonance Raman effect, or when coupled with other techniques such as confocal microscopy, Raman spectroscopy is becoming more and more applicable to the types of assay being conducted in lab-on-a-chip applications, such as flow cytometry, cell patterning and trapping, and microarrays, all of which often involve the detection of extremely low quantities of analyte. Surface enhanced Raman scattering (SERS, or when coupled with the resonance Raman phenomenon, SERRS) spectroscopy has proven to be of particular use as a robust optical detection method in microfluidic environments. In this paper, we demonstrate the use of SERRS multiplex detection to quantitatively characterize individual microdroplets in a continuous stream whose contents are gradually varied using a bespoke pump control algorithm.

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“…Captured particles, like solid silica spheres, hollow polymer spheres and single cells, can then be manipulated and moved as though held by remarkably fine tweezers. Optical tweezers have been used on trypanosomes for multiple purposes [ 11 , 28 , 29 , 30 , 31 , 32 ]. For example, optical tweezers were employed to separate and distinguish trypanosomes from other cells [ 30 , 31 ], to analyse their chemotactic behaviour [ 28 ] and to measure the forces created by their flagellar motors [ 11 ].…”

Section: Separation Of Trypanosomes Using Optical Tweezers and Drumentioning

confidence: 99%

“…Optical tweezers have been used on trypanosomes for multiple purposes [ 11 , 28 , 29 , 30 , 31 , 32 ]. For example, optical tweezers were employed to separate and distinguish trypanosomes from other cells [ 30 , 31 ], to analyse their chemotactic behaviour [ 28 ] and to measure the forces created by their flagellar motors [ 11 ]. Whilst it is possible to estimate the forces and energy consumption of freely swimming cells [ 33 ], optically confined cells can be studied at higher magnification in greater detail.…”

Section: Separation Of Trypanosomes Using Optical Tweezers and Drumentioning

confidence: 99%

Microfluidics-Based Approaches to the Isolation of African Trypanosomes

et al. 2017

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African trypanosomes are responsible for significant levels of disease in both humans and animals. The protozoan parasites are free-living flagellates, usually transmitted by arthropod vectors, including the tsetse fly. In the mammalian host they live in the bloodstream and, in the case of human-infectious species, later invade the central nervous system. Diagnosis of the disease requires the positive identification of parasites in the bloodstream. This can be particularly challenging where parasite numbers are low, as is often the case in peripheral blood. Enriching parasites from body fluids is an important part of the diagnostic pathway. As more is learned about the physicochemical properties of trypanosomes, this information can be exploited through use of different microfluidic-based approaches to isolate the parasites from blood or other fluids. Here, we discuss recent advances in the use of microfluidics to separate trypanosomes from blood and to isolate single trypanosomes for analyses including drug screening.

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Optoelectronic tweezers for medical diagnostics

Cited by 4 publications

References 0 publications

Highly Localized Enrichment of Trypanosoma brucei Parasites Using Dielectrophoresis

Highly Localized Enrichment of Trypanosoma brucei Parasites Using Dielectrophoresis

Characterization of individual microdroplets by SERRS spectroscopy

Microfluidics-Based Approaches to the Isolation of African Trypanosomes

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