45 research outputs found
Microfluidic particle tracking technique towards white blood cell subtype counting and serum protein quantification
No full textMicrofluidic technologies have gained wide acceptance in the past decade as diagnostics tools in clinical setting world-wide. This is primarily due to the fact that microfluidic technologies enable rapid, quantitative assays from small amount of physiological sample in an easy-to-use, portable platform. In this work, we will describe a microfluidic technique that can be built upon to count white blood cell subtypes or serum protein from a drop of blood. Traditionally, researchers have counted white blood cell subtypes by capturing them. However, an elegant and more accurate way to do the same is by exploiting the transitory interactions between the antigen on the surface of the cell and a cognate antibody. Cells expressing the antigen of interest will take longer to traverse a microchannel which has been coated with a cognate antibody compared to the cells which don't express that antigen. To our knowledge, no microfluidic assay exists which can rapidly count cells using this principle. Towards this end, we have developed a repeatable experimental technique to control the transit time and the order of particles in a microchannel. To least affect the uniformity of transit time, we have also optimized the geometry of pillars in the microchannel on which antibodies are functionalized.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2018-08-01The student, Tanmay Ghonge, accepted the attached license on 2016-07-20 at 20:20.The student, Tanmay Ghonge, submitted this Thesis for approval on 2016-07-20 at 20:22.This Thesis was approved for publication on 2016-07-22 at 15:07.DSpace SAF Submission Ingestion Package generated from Vireo submission #10043 on 2016-11-10 at 12:21:02Made available in DSpace on 2016-11-10T18:27:09Z (GMT). No. of bitstreams: 2
GHONGE-THESIS-2016.pdf: 2007682 bytes, checksum: 2e84b6da47c9ce69ad66e0b45f92a31f (MD5)
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Previous issue date: 2016-07-22Embargo set by: Seth Robbins for item 95295
Lift date: 2018-11-10T18:28:02Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 95295 on 2018-11-11T10:15:11Z
Point-of-care microfluidic assays for measuring expression level of antigen on blood cells
No full textElevated expression of a membrane protein CD64 on neutrophils is linked with the onset of sepsis, a life-threatening syndrome that contributes to millions of deaths annually worldwide. The survival rate of septic patients falls rapidly every hour the appropriate medication is delayed. Therefore, automated and periodic measurements of CD64 expression (nCD64) at the patient’s bedside could lead to timely medical intervention, thereby saving lives and billions of dollars. Gold standard assays for measuring nCD64, such as flow cytometry, require manual sample preparation and long incubation times. For point-of-care applications, however, an assay should be able to measure nCD64 with little to no sample preparation.
This dissertation addresses the need by investigating portable, point-of-care platforms for measuring nCD64 from whole blood without any off-chip sample preparation. Our first platform is an electrical biosensor that measures nCD64 by measuring the fraction of immunologically captured cells expressing CD64. It consists of a capture chamber, for immunologically capturing cells and microfluidic coulter counters at its entrance and exit. In our study, we found that the fraction of cells expressing CD64 correlates linearly with nCD64. For our study, we optimized the geometry of the capture chamber and the coulter counters from the first principles of fluid mechanics and electrostatics respectively. This biosensor can produce a readout of nCD64 starting from just 10 μL of blood in 10 mins. Although this technique does not require off-chip sample preparation, red blood cells have to be lysed on-chip so that white blood cells can be counted by the electrical counters.
Lysing red blood cells on-chip adds a step which requires multiple pumps running in parallel. Ideally, the technique should be able to measure nCD64 without red blood cell lysis. Towards that, we have developed an optical, microfluidic cell capture assay that works from whole blood. We demonstrate the proof-of-concept of this assay by measuring the density of biotin molecules on beads. We injected beads in a capture chamber that is functionalized with neutravidin. Beads that have a higher density of travel, on average, shorter distances in the chamber before they get captured compared to the beads with a lower density of biotin. We developed a statistical model to extract the probability of capture (ε) per interaction with a pillar from the spatial distribution of beads in the channel. ε is found to be linearly proportional to the surface density of biotin.
We expanded this optical technique to measure the nCD64 on neutrophils. One μL blood whole blood is injected in a microfluidic channel consisting of a capture chamber functionalized with anti-CD64 antibodies. As was the case with beads, the immunologically captured have a distinct spatial signature of capture depending on the CD64 expression level. Samples with higher CD64 expression travel, on average, a shorter distance in the channel. Using the same statistical model used to quantify biotin density on beads, we quantified CD64 expression on neutrophils. To make this technique easily translatable to a point-of-care device, we assembled a smartphone-imaging set-up to replace bulky microscopes. Our smartphone microscope can measure CD64 from whole blood without the need for any sample preparation in about 20 mins. We believe that deploying this technology in hospitals could save millions of lives worldwide.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-05-01The student, Tanmay Ghonge, accepted the attached license on 2019-02-19 at 21:50.The student, Tanmay Ghonge, submitted this Dissertation for approval on 2019-02-19 at 21:56.This Dissertation was approved for publication on 2019-02-28 at 09:39.DSpace SAF Submission Ingestion Package generated from Vireo submission #13396 on 2019-08-22 at 16:19:57Made available in DSpace on 2019-08-23T20:44:32Z (GMT). No. of bitstreams: 4
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Previous issue date: 2019-02-28Embargo set by: Seth Robbins for item 112254
Lift date: 2021-08-23T20:44:50Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112254
Lift date: 2021-08-23T20:46:41Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112254
Lift date: 2021-08-23T20:47:38Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 112254
Lift date: 2021-08-23T20:48:32Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 112254 on 2021-08-24T09:15:20Z
The Waterfall
No full textMillions of people die every year of treatable diseases for the want of diagnosis in lesser privileged parts of the world. Traditional techniques to quantify proteins in blood serum, which are biomarkers for many
of these treatable diseases, either have huge installation cost and/or require a trained personnel, both of which are absent in resource-limited regions. We have developed an inexpensive technique to quantify
proteins in blood serum. First, we transfer the protein from blood serum onto the surface of tiny beads. Then, these beads are then made to flow through an obstacle course of pillars. As the beads trickle down the obstacle course, a sticky molecule present on the pillars captures the protein bearing beads. The image shows captured beads in one such obstacle course. The average distance traveled by the beads is a measure of how much protein was present in the blood serum. Thus, this technique provides a simple and automated way of quantifying protein in blood serum. This image bears an uncanny resemblance to a waterfall not far from my home in India. Thousands of miles away from my home, I am thrilled to have stumbled upon a 'waterfall' in my lab.Ope
The Waterfall
No full textMillions of people die every year of treatable diseases for the want of diagnosis in lesser privileged parts of the world. Traditional techniques to quantify proteins in blood serum, which are biomarkers for many
of these treatable diseases, either have huge installation cost and/or require a trained personnel, both of which are absent in resource-limited regions. We have developed an inexpensive technique to quantify
proteins in blood serum. First, we transfer the protein from blood serum onto the surface of tiny beads. Then, these beads are then made to flow through an obstacle course of pillars. As the beads trickle down the obstacle course, a sticky molecule present on the pillars captures the protein bearing beads. The image shows captured beads in one such obstacle course. The average distance traveled by the beads is a measure of how much protein was present in the blood serum. Thus, this technique provides a simple and automated way of quantifying protein in blood serum. This image bears an uncanny resemblance to a waterfall not far from my home in India. Thousands of miles away from my home, I am thrilled to have stumbled upon a 'waterfall' in my lab.Open Restriction set for Item 99079 on 2017-04-21T15:06:47Z with date null by [email protected] by Ian Harmon ([email protected]) on 2017-04-21T15:08:37Z
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Previous issue date: 2017Ope
Point-of-care microfluidic assays for measuring expression level of antigen on blood cells
No full textElevated expression of a membrane protein CD64 on neutrophils is linked with the onset of sepsis, a life-threatening syndrome that contributes to millions of deaths annually worldwide. The survival rate of septic patients falls rapidly every hour the appropriate medication is delayed. Therefore, automated and periodic measurements of CD64 expression (nCD64) at the patient’s bedside could lead to timely medical intervention, thereby saving lives and billions of dollars. Gold standard assays for measuring nCD64, such as flow cytometry, require manual sample preparation and long incubation times. For point-of-care applications, however, an assay should be able to measure nCD64 with little to no sample preparation.
This dissertation addresses the need by investigating portable, point-of-care platforms for measuring nCD64 from whole blood without any off-chip sample preparation. Our first platform is an electrical biosensor that measures nCD64 by measuring the fraction of immunologically captured cells expressing CD64. It consists of a capture chamber, for immunologically capturing cells and microfluidic coulter counters at its entrance and exit. In our study, we found that the fraction of cells expressing CD64 correlates linearly with nCD64. For our study, we optimized the geometry of the capture chamber and the coulter counters from the first principles of fluid mechanics and electrostatics respectively. This biosensor can produce a readout of nCD64 starting from just 10 μL of blood in 10 mins. Although this technique does not require off-chip sample preparation, red blood cells have to be lysed on-chip so that white blood cells can be counted by the electrical counters.
Lysing red blood cells on-chip adds a step which requires multiple pumps running in parallel. Ideally, the technique should be able to measure nCD64 without red blood cell lysis. Towards that, we have developed an optical, microfluidic cell capture assay that works from whole blood. We demonstrate the proof-of-concept of this assay by measuring the density of biotin molecules on beads. We injected beads in a capture chamber that is functionalized with neutravidin. Beads that have a higher density of travel, on average, shorter distances in the chamber before they get captured compared to the beads with a lower density of biotin. We developed a statistical model to extract the probability of capture (ε) per interaction with a pillar from the spatial distribution of beads in the channel. ε is found to be linearly proportional to the surface density of biotin.
We expanded this optical technique to measure the nCD64 on neutrophils. One μL blood whole blood is injected in a microfluidic channel consisting of a capture chamber functionalized with anti-CD64 antibodies. As was the case with beads, the immunologically captured have a distinct spatial signature of capture depending on the CD64 expression level. Samples with higher CD64 expression travel, on average, a shorter distance in the channel. Using the same statistical model used to quantify biotin density on beads, we quantified CD64 expression on neutrophils. To make this technique easily translatable to a point-of-care device, we assembled a smartphone-imaging set-up to replace bulky microscopes. Our smartphone microscope can measure CD64 from whole blood without the need for any sample preparation in about 20 mins. We believe that deploying this technology in hospitals could save millions of lives worldwide.LimitedAuthor requested closed access (OA after 2yrs) in Vireo ETD syste
Steric-effect-induced alteration of thermal transport phenomenon for mixed electroosmotic and pressure driven flows through narrow confinements
No full textThe present paper addresses, for the first time, the thermal transport process for mixed electroosmotic and pressure-drive flows of electrolyte solutions, through nanoscopic confinements with step-change in the wall temperature, by going beyond the prevalent simplifying assumption of non-interacting, point charge behaviour of the ions in the electrolyte solution. An attempt is made here to delineate the alterations in the heat transfer characteristics induced by the inclusion of the finite ionic size effect or the ‘steric effect’, in the electrokinetic framework, which becomes very significant for electro-hydrodynamic flows through narrow-confinements with high surface charge density. Under such situations the finite size of the ions cannot be trivially precluded from the analysis, thereby rendering the point charge assumption erroneous. The distinctive influence of the ‘steric’ effect of ions on the heat transfer characteristics is numerically investigated by delineating the variations in the local liquid temperature, local Nusselt number and the thermal entrance length for the thermally developing regime. The observed significant influences of the bulk volume fraction of ions, as represented by the steric factor, on the thermal transport phenomenon are physically explained by simultaneously highlighting their intrinsic differences with the effects of other existing parameters, like Joule heating and viscous dissipation. The utilitarian scope of the work lies in the fact that it proposes a more comprehensive methodology for analyzing the heat transfer characteristics in state-of-the-art nanoscale electromechanical devices
Temporal Synchronization of Sensors
No full textAdvanced automotive vehicles are based on the real-time fusion of an increasing number of automotive sensors. For precise fusion of different sensors, measurements need to be synchronized both temporally and spatially. This thesis aims to design a hardware temporal synchronization block as part of the PRISTINE systolic array accelerator project for multi-sensor data fusion. In this process, we study and address several temporal sensor synchronization issues that are characteristic of the considered system as well as any other typical sensor fusion system. First and foremost, we handle the problem of estimating the actual time of sensor measurement by exploring well-known filtering techniques such as Kalman, mean and median filters. A suitable filter is selected for implementation based on the statistical characteristics of the observed sensor cycle times, the complexity of the filters and the quality of obtained estimates. Next, we address the issue of reconstructing incoming sensor data streams according to the estimated sensor measurement times while maintaining minimal latency and synchronization error by employing an adaptive stream buffering technique utilized in distributed multimedia systems. An analysis of the effects of the stream synchronization algorithm's parameters on buffering latency and synchronization error was presented. Finally, the above synchronization solution was efficiently implemented on hardware by making certain modifications and design decisions to the algorithm. A method to evaluate the whole temporal synchronization process is proposed and the obtained results on real sensor data are presented.PRYSTINEElectrical Engineering | Circuits and System
Multi-disciplinary Optimization of Rotor Nacelle Assemblies for Offshore Wind Farms: An Agile Systems Engineering Approach
No full textThe models with different fidelities for the siloed application of niche wind farm disciplines - rotor aerodynamics, aeroelasticity or wake aerodynamics - are prevalent in literature. These models are often used sequentially while designing a wind farm that may lead to a sub-optimal design due to their agnosticism towards the inter-disciplinary influences. This paper demonstrates the multi-disciplinary optimization of rotor nacelle assemblies for offshore wind farms. The designs of three aspects of rotor nacelle assembly are addressed - rotor blade, power density and drive train configuration - that support the development of an open-source agile systems engineering framework and allow flexibility in their utility to various stakeholders of offshore wind farms.Electrical Engineering | Sustainable Energy Technolog
Electrohydrodynamics within the electrical double layer in the presence of finite temperature gradients
No full textA wide spectrum of electrokinetic studies is modeled as isothermal ones to expedite analysis even when such conditions may be extremely difficult to realize in practice. Going beyond the isothermal paradigm, we address here the case of flow induced electrohydrodynamics, commonly streaming potential flows, in a situation where finite temperature gradients do exist. By way of analyzing a model problem of flow through a narrow parallel-plate channel, we show that the temperature gradients applied at the channel walls may have a significant effect on the streaming potential, and, consequently, on the flow itself. Our model takes into consideration all the pertinent phenomenological aspects stemming from the imposed thermal gradients, such as the Soret effect, the thermoelectric effect, and the electrothermal effect, by a full-fledged coupling among the electric potential, the ionic species distribution, the fluid velocity and the local fluid temperature fields, without resorting to ad hoc simplifications. We expect this expository study to contribute significantly towards more sophisticated future endeavors in actual development of micro- and nano-devices for applications simultaneously involving thermal management and electrokinetic effects
An Ultrasonically-Powered System for 1.06mm<sup>3</sup> Implantable Optogenetics and Drug Delivery Dust
No full textThis brief presents an ultrasonically powered micro-system for deep tissue optogenetic stimulation. The developed system is composed of a Base for Powering and Controlling (BPC) and an implantable Dust for optogenetics and drug delivery. The Dust consists of a piezoelectric crystal, a rectifier chip, and a micro-scale custom-designed light-emitting-diode (μ LED) integrated, miniaturized, and envisioned to be used for freely moving animal studies. The proposed Dust operates in frequencies up to 5 MHz, power levels in the 0-10 mW range, achieves start-up within 1.8~μ s at 2.9 MHz operating frequency at 14.4 mW/mm2 ultrasound power density, and 98.1% chip efficiency at 2 mW input power. With the BPC implemented and attached to ( 500~μ m )3 PZT4 crystals, set to 60 V at 2.8 MHz operating frequency at 3 mm distance in demineralized water, the dust delivered up to 6 mW to its load (μ LED for optogenetics), which translates to 0.11% total system efficiency.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Bio-Electronic
