PIs: Dr. Reza Sadr, Dr. Arum Han, Dr. Ali Adibi, Dr Anoop Baby and Dr. Abdulrahman Arabi

Consultant: Dr. Jean-Charles Grivel (Sidra Medical and Research Centre)

Cardiovascular diseases (CVD) are the leading cause of death world-wide that needs to be treated with immediate hospitalization and revascularization. Based on data released for 2013, 12.9 percent of registered deaths in Qatar were related to CVD. Among the Qatari population, the share of mortality related to CVD was 12.2 percent. Diagnosis of acute coronary syndrome (ACS) and assessment of the underlying risk factors of CVD at the point-of-care (PoC) will likely play a crucial role in enabling rapid diagnosis and treatment, and thus reducing morbidity, mortality, and healthcare costs. The main goal of this proposal is to develop a low-cost, compact, rapid, reliable, sensitive, and easy-to-use PoC CVD diagnostic tool that determines concentrations of several cardiac biomarkers (in blood). This information can then be processed to provide immediate information regarding cardiovascular risk factors. Such comprehensive biomarker analysis can potentially provide additional immediately actionable information, not available by current standard methodologies that are expensive and subject to delays. Our approach aims for establishing a rapid and reliable diagnostic method that can detect CVD risk factors and ACS.

 To achieve the envisioned goal, we will develop a high throughput and highly sensitive multiplexed sensing platform based on a simple single-step assay enabled by integration of 1) a compact and high-throughput continuous flow sample preparation module for blood plasma extraction and filtering, 2) a continuous-flow electrokinetic analyte pre-concentrator that can provide 100 to 1000 fold enhancement of target biomarker concentrations, 3) a compact multiplexed sensing platform based on resonance wavelength shift measurement in a densely-integrated array of high-quality factor (Q) photonic resonators, 4) a panel of high-quality biomarker-specific capture antibodies with a non-fouling surface coating to minimize the nonspecific binding to the sensor surface, and 5) an array of on-chip reference elements to calibrate the sensor measurement and compensate for the effect of nonspecific binding and drift errors caused by sensing device drifts or other environmental effects. The resulting sensing platform enables the rapid detection of multiple cardiac biomarkers at the point-of-care with reasonable sensitivity.

 The outcome of this project will be a prototype system for PoC detection of cardiac biomarkers with the ability to simultaneously screen up to 10 biomarkers using a single drop of blood. To reduce the overall costs, the proposed solution will be designed in such a way that it can be miniaturized in the form of a compact reader system working with disposable sensor cartridges. The experimental demonstrations in this program will be performed using a bench-top reader system with the possibility of being miniaturized into a hand-held reader system in a follow-on program. As such, the focus of this program (with the requested budget) is to address the fundamental challenges for the development of such a transformative sensing approach with a practical (manufacturable) solution.

The envisioned commercial target system will be composed of a disposable sensor cartridge and a hand-held reader system in which the collected blood sample is directly applied to the sensor cartridge, and the sensor is plugged into the reader system. The reader system provides the control signal for the assay process, reads the sensor measurement data, and performs the required data processing steps to provide the information on different biomarkers circulating concentration in blood We will demonstrate the performance of the different subsystems individually initially (the performance of the microfluidic subsystem with commercially available human whole blood sample and that of the optical sensing module with a plasma-based fluid that mimics the output of the microfluidic subsystem).

The blood sample will be applied to the cartridge and continuously flow through a flow meter to measure the input blood flow rate, as the biomarker concentration in the whole blood needs to be measured, not just the absolute quantity. The input sample then flows through a set of microfluidic filter structures at three stages to remove all blood cell components, followed by flowing through a pre-concentrator unit to pre-concentrate protein components in the blood. The concentrated sample then flows through an array of compact photonic resonators, each coated with a different antibody that binds to one of the target biomarkers in the panel, enabling multiplexed sensing of a panel of cardiac biomarkers.

  The final developed system is expected to have the potential to concurrently screen up to 20 biomarkers (although only up to 10 will be demonstrated in this project, still a significant improvement over the current 1-3 commonly tested in PoC devices) in a small blood sample (~ 20 μL) in less than 10-20 minutes and to provide a limit of detection (LOD) down to pg/mL and a dynamic range better than 5-6 orders of magnitude for most biomarkers.

Upcoming Project: Lab-on-Chip system for point-of-care cardiac biomarker screening

Microfluidic platforms for high throughput screening of microbes utilizing wastewater

PIs: Dr. Reza Sadr, Dr. Arum Han, Dr. Choongho Yu and Dr. Paul de Figueiredo

Biogas such as bio-hydrogen generated from biomass is of great interest as renewable “green” energy sources. Microbes in nature commonly break down organic compounds into hydrogen and methane through anaerobic digestion, and have been utilized in industry for biogas generation through fermentation processes. Unfortunately, current microbe mediated bioenergy generation technologies are in their early stages of development with low efficiency due to the lack of (i) known electrochemically active microbes with high efficiency or conversion capabilities; (ii) knowledge of best cultivating/operating conditions; and (iii) understanding of the metabolic mechanisms of the few currently known electrochemically active microbes. Extensive research is required to identify and characterize appropriate microbes as well as to test diverse cultivation/operating conditions, which will significantly enhance the bioenergy generation capabilities and efficiencies of these systems.

 Here we propose to develop a sensing platform that consists of microfluidic microbial culture arrays and multiplexed nanowire gas sensor arrays to overcome the technological barriers in investigating various microbe-mediated bioenergy generation systems. This novel microfluidic platform will be capable of continuously quantifying microbe-mediated bio-hydrogen generation in a high-throughput parallel fashion. This platform will enable us to identify the most desirable microbes for these applications and to optimize cultivation/operating conditions for biogas generation. This research will dramatically improve the performance of microbial biogas generation as well as set the stage for gaining a basic understanding of metabolic mechanisms that mediate microbial biogas biosynthesis. The proposed sensing platform can also be applied as an experimental simulation device or portable sensing system for biogas generation in medium to large-scale bioreactors. Therefore, this work will also enable translating basic science findings into large-scale bioenergy production and next-generation bioreactor designs. This project work investigates on different aspects of how to improve energy harvesting from organic waste utilizing bio-electrochemically active microorganisms in microbial electrolysis cell (MEC) and microbial fuel cell (MFC) format.

The study was undertaken both numerically and experimentally with the specific objectives to each sub-topic as detailed below:

Microbial Electrochemical Cell Flow Chamber Analysis and Design

This study was conducted in order to investigate how different lengths, packing densities, and surface conditions of CNTs used as anodes affect MFC power output, as well as propose a CNT-decorated anode configuration that maximizes electron transfer. It is expected that this systematic study will result in design principles for developing next-generation nanomaterial electrodes.

Based on the simulation results above, the optimal chamber geometry that has the longest distance between the inlet and outlet port should perform the best in terms of retaining the fresh incoming substrate fluid.

Three-Dimensional Porous Carbon Nanotube Sponge Anode and Cathode

The objective of this study is to develop a one-step process for synthesizing porous and flexible 3D CNT sponges by using a simple and facile one-step process without the need for any substrates or base/sacrificial materials.  We also developed a two-stage process for fabricating three-dimensional (3D) nitrogen-enriched iron-coordinated CNT (N/Fe-CNT) sponges as high-performance cathodes using simple and low-cost fabrication processes.

ZnO Nanowires Based Compact Gas Sensor for Monitoring Hydrogen Production from Microbial Electrolysis Cells (MECs)

The main objective of this study was to develop a low cost and compact ZnO nanowire-based compact gas sensor that can detect both hydrogen and methane gases.

Biofilm Analysis using a Laminar Flow Microbial Fuel Cell

In this part, the correlation between biofilm thickness and power production is investigated as it is known at biofilm growth on anode affect the power production in MFC/MECs.

Fresh substrate retention

The objective of this work is to investigate the flow field and mixing rates for some commonly used MFC/MEC chamber designs, assuming no chemical reactions inside the anode chamber. A commercial CFD solver is used to model the flow in a micro-scale Y-junction.

Mixing Characteristic of Parallel Flow in a Y-junction

This work presents overall characteristics of the mixing layer in a multi-channel continuous-flow BES system under different flow conditions and different geometries in the presence of growing biofilm.  It serves as guidance for designing experiments to study how biofilm influences BES system performances.

Droplet Breakup in Microchannel

The main objective of this study is to examine the breakup mechanism of a droplet at an asymmetric T-junctions with different lengths to the outlet branches was examined.  While it is known that the viscosity ratio between the phases would affect the breakup process, the effects of the viscosity ratio is not entirely clear.

 

Biofluidics