Point-of-Care Diagnostics & Global Health 2018 Agenda

Wearable Microfluidic and Microtubular Sensors For Biomedical Applications
Chwee Teck Lim, NUS Society Chair Professor, Department of Biomedical Engineering, Institute for Health Innovation & Technology (iHealthtech), Mechanobiology Institute, National University of Singapore, Singapore

The future of healthcare wearables lies in continual sensing in an unobtrusive manner. Tactile sensing is especially important to capture mechanotransduced signals arising from the body, or as a result of interactions with the external environment. However, conventional sensors are rigid, stiff and obstrusive. Therefore, one of the key objectives is to confer flexibility and stretchability to our sensing elements, while maintaining its sensitivity and robustness. Here, we develop a novel liquid-based microfluidic and microtubular sensors that possess high flexibility, durability, and sensitivity. The sensors comprise a soft elastomer-based microfluidic template encapsulating a conductive liquid which serves as the active sensing element of the device. This sensor is capable of distinguishing and quantifying the various user-applied mechanical forces it is subjected to. We demonstrated biomedical applications of our sensors in rehabilitation monitoring, artificial sensing and disease tracking such as that for diabetic patients. Overall, our work highlights the potential of the liquid-based microfluidic sensing platform in a wide range of biomedical applications and further facilitates the exploration and realization of functional liquid-state device technology.

Wearable Microfluidics For Real-Time Personal Monitoring
Martyn Boutelle, Professor of Biomedical Sensors Engineering, Imperial College London, United Kingdom

Tissue functions at a cellular level by exchange of molecules either between cells and blood or between the cells themselves. This produces patterns of molecular change that are diagnostic of cellular processes whose origin can be physiological (exhaustion, pregnancy) or pathological (ischemia, renal failure, cancer). Our technologies have now developed to a point where we can aspire to do more than this, to measure from patients in real-time. The has the great benefit that it is them possible to understand the evolution of disease, the effectiveness of treatments, and ultimately to guide treatment. In this presentation I will describe the development of microfluidic devices connected to wireless electronics for transplant organ, patient and athlete monitoring. Tissue sampling is via an integrated microfluidic device, a microdialysis probe. Molecular biomarkers are measured using microscale integrated amperometric biosensors and solid-contact ion-selective electrodes (ISE) for tissue ionic balance. For detailed patterns of ionic responses we have developed  high density Field Effect Transistor (FET) array which function as ISEs within the flow stream. We have also edevelodp multiphase  flow microfluidic systems for highest time resolution.The presentation with describe the design and optimization challenges and include clinical examples from our recent work.

Advancing the Performance of Low Cost Diagnostics For Global Health
Bernhard Weigl, Director, Center for In-Vitro Diagnostics, Intellectual Ventures/Global Good-Bill Gates Venture Fund, United States of America

We will present lab and field results with recently developed lateral flow and similar assays for global health. Our group’s mission is to develop assays for use in global health applications that are as sensitive as the best conventional diagnostic assays (in some cases even better) while retaining cost, simplicity, and usability advantages. For our lateral flow assay work we have developed a 3D modeling platform for paper-based assays and are using it to determine the theoretical limit of a particular assay variant, as well as a rapid array-based empirical optimization system for lateral flow assays. Together, these approaches allow the development of more sensitive assays with shortened development time. We will describe the assay optimization methods we employ, as well the use of these methods in the development of several assays under development, including ones for malaria, and TB.

Absolute Quantification of Molecular Biomarkers
Hsueh-Chia Chang, Bayer Professor of Chemical and Biomolecular Engineering, University of Notre Dame, Interim Chief Technology Officer, Aopia Biosciences, United States of America

We report several micro/nanofluidic technologies we invented that can overcome the sensitivity obstacles for liquid biopsy:  (1) A chip electrophoresis module for high-yield exosome extraction without centrifugation;  (2) A Surface Acoustic Wave exosome lysing module that replaces chemical lysing and eliminates the need for low-yield solid/liquid miRNA extraction;  (3) A solid-state  polymer nanopore fM assay that can delay translocation of short 20-nt miRNAs and differentiate the duplexes that have hybridized with inserted oligos and the wild-type miRNAs; (4) A Carbon-Nanotube Protein Sensor with fM sensitivity, three orders of magnitude below KD. Integrated into a biochip, these technologies allow us to quantify protein biomarkers for breast cancer and miRNAs for pancreatic cancer, from patient blood samples, at sensitivities far better than CTC and current molecular biomarker assays, with dramatically improved AUC and p values.  We have eliminated low-yield extraction steps and employed irreversible kinetics to achieve such high performances and have allowed absolute quantification without the need for house-keeping reference molecules.

Nanosensors for Single-molecule Sequencing
Steve Soper, Foundation Distinguished Professor, Director, Center of BioModular Multi-Scale System for Precision Medicine, The University of Kansas, United States of America

We are generating a single-molecule DNA sequencing platform that can acquire sequencing information with high accuracy. The technology employs arrays of nanosensors that read the identity of individual mononucleotides from their characteristic electrophoretic mobility and current transient amplitudes through a 2-dimensional (2D) nanochannel (~20 nm in width and depth; <10 µm in length) fabricated in a thermoplastic via nano-imprinting (NIL). The mononucleotides are generated from an intact DNA fragment using a highly processive exonuclease, which is covalently anchored to a plastic solid support contained within a bioreactor that sequentially feeds mononucleotides into the 2D nanochannel. We will discuss the operation of this nanosensor in this presentation as well as its production.

Quantum Diagnostics: From Single Cells to Single Molecules
Dino Di Carlo, Armond and Elena Hairapetian Chair in Engineering and Medicine, Professor and Vice Chair of Bioengineering, University of California-Los Angeles, United States of America

The ultimate limits of sensitivity in measuring biological systems occurs at the level of single-cells and single-molecules. I will discuss our approaches leveraging microfluidic and microfabrication technologies to interface at the scale of these single entities. In particular, we make use of the ability to compartmentalize fluid volumes to a sub-nanoliter scale and manipulate cells using unique microscale physics. I will discuss progress in using these quantized or digital measurements towards single-molecule infectious disease diagnostics, characterizing the immune evasion state of circulating tumor cells, and screening for drugs that modulate the contractile forces that single muscle cells apply.

Integrated Isolation, Detection and Analysis of cf-DNA and Exosome Biomarkers from Cancer Patient Blood Samples - The Road to POC Liquid Biopsy Diagnostics
Michael Heller, Professor, Dept Bioengineering, University of California-San Diego, United States of America

New AC electrokinetic (ACE) microarray/chip device allows 15-20-minute isolation of cancer related cf-DNA, exosomal RNA and protein biomarkers directly from 20-50ul of patient blood, plasma or serum. Cf-DNA levels can be immediately determined directly on the chip (in-situ) using DNA specific dyes and then immunofluorescent analysis can be carried out to identify exosomal protein biomarkers. Presently, cf-DNA and exosomal RNA are then eluted from the ACE chip, and PCR and sequencing analysis carried out to identify the cancer-related point mutations. New procedures are now being developed to carry out on-chip PCR for DNA/RNA analysis. On-chip integration of proteomic and genomic analysis is a major step forward in the quest for seamless sample to answer POC liquid biopsy diagnostics.

Cost-effective and Globally Deployable Mobile Diagnostics Using Paper-Based Nanobiosensors
Arben Merkoçi, ICREA Professor and Director of the Nanobioelectronics & Biosensors Group, Institut Català de Nanociencia i Nanotecnologia (ICN2), Barcelona Institute of Science and Technology (BIST), Spain

Point of care devices are progressing rapidly and the demand for cost efficient globally deployable mobile diagnostics platforms is the key factor for their success. Physical, chemical and mechanical properties of cellulose in both micro and nanofiber-based networks combined with their abundance in nature or easy to prepare and control procedures are making these materials of great interest while looking for cost-efficient and green alternatives for device production technologies. Both paper and nanopaper-based biosensors are emerging as a new class of devices with the objective to fulfil the “World Health Organization” requisites to be ASSURED: affordable, sensitive, specific, user-friendly, rapid and robust, equipment free and deliverable to end-users. How to design simple paper-based biosensor architectures? How to tune their analytical performance upon demand? How one can ‘marriage’ nanomaterials such as metallic nanoparticles, quantum dots and even graphene with paper and what is the benefit?  How we can make these devices more robust, sensitive and with multiplexing capabilities? Can we bring these low cost and efficient devices to places with low resources, extreme conditions or even at our homes? Which are the perspectives to link these simple platforms and detection technologies with mobile phone communication? I will try to give responses to these questions through various interesting applications related to protein, DNA and even contaminants detection all of extreme importance for diagnostics, environment control, safety and security.

Integrating Aptamer Technology with Paper-Based Point-of-Care Devices for Biomedical Monitoring
John Brennan, Professor and Director, Biointerfaces Institute, McMaster University, Canada

DNA aptamers and DNA enzymes (denoted as functional nucleic acids or FNA) are an emerging platform for development of point-of-care (POC) diagnostic devices.  In this presentation, I will first focus on the development of new aptamers and DNA enzymes for a range of key biomarkers and their integration into colorimetric and fluorimetric assays for a variety of targets, mainly in the area of infectious disease.  Methods to couple target binding to FNAs to produce a DNA strand as an output, and to then use the output DNA to initiate isothermal amplification (ITA), will then be described.  Finally, the printing of specific “modules” for recognition (FNA), amplification (via ITA) and detection onto paper devices will be described as a way to generate a range of new POC devices that allow facile detection of a range of clinical analytes.  Examples will be provided to demonstrate multi-step reactions on paper for ultra-sensitive detection of E. coli, C. difficile, MRSA and H. pylori.