Rapid Diagnostic Testing 2022 - SARS-CoV-2 & Beyond Agenda

One Size Does Not Fit All: COVID-19 Testing Strategies
Joanna Sickler, Head of Healthcare Systems Policy, Roche Diagnostics, United States of America

Effective implementation of diagnostic tests requires an understanding of strengths and weaknesses of each technology platform.  Molecular, antigen, point-of-care, home testing and central lab solutions are all needed to meet the challenge of the COVID-19 pandemic.  This presentation will focus on the product characteristics of the rapid point-of-care technologies that are available today, strategies for effective use in testing programs and gaps in the current testing landscape.

Affinity Selection and Enumeration of SARS-CoV-2 Viral Particles from Saliva Samples using Integrated and Modular Microfluidic Systems for COVID-19 Diagnostics
Steve Soper, Foundation Distinguished Professor, Director, Center of BioModular Multi-Scale System for Precision Medicine, The University of Kansas, United States of America

Coronavirus disease 2019 (COVID-19) arises from the SARS-CoV-2 virus and has been found to be highly contagious. To mitigate spreading, testing has been deemed an important asset. Testing has predominately utilized RT-qPCR as well as serological-based tests. However, while new machines are rolling out for point-of-care testing (POCT), issues are present with these common testing systems, for example the need for reagents (e.g. enzymes, fluorescent reporters, antibodies), workflows that sometimes require specialized operators, and the inability to distinguish between infectious and non-infectious individuals, which is important in determining the need for quarantining. We report an innovative COVID-19 diagnostic test that directly addresses the aforementioned issues. The assay accepts a clinical sample and specifically selects SARS-CoV-2 particles from the sample using surface-immobilized DNA aptamers targeting the spike protein, releases photolytically the selected viral particles (VPs), and then counts the number of SARS-CoV-2 particles using a label-free approach. The workflow is simple and fully automated and also, no reagents are required once the assay is deployed for testing. The entire assay was carried out using microfluidic chips made from a plastic that were injection molded to allow for high scale production at low cost. The VP selection chip consisted of 1.5 million pillars that allowed for affinity loading up to 1010 SARS-CoV-2 particles at a recovery ~90%. Following selection, the VPs were released from the capture surface using a photocleavable linker by a blue-light LED (79% release efficiency) and subsequently counted using a nano-Coulter Counter (nCC). For high throughput single VP counting, 5 nCCs were placed in parallel and offered 100% detection efficiency for VPs travelling through a 200 nm pore. These two chips were interconnected through the use of a fluidic motherboard, also made from a plastic; the integrated system allowed for complete sample processing automation. The system’s valving employed plastic membranes made from an elastomeric COC. The entire assay could be completed in <20 min. In a 20 patient blinded study, the test correctly identified 10 non-infected individuals (clinical specificity = 100%) and in 5 COVID-19 patients, VPs were detected indicative of “active” disease, while 4/5 others were deemed infected by RT-qPCR, but those individuals had no VPs suggesting these patients were not contagious (clinical sensitivity = 95%).

Developing Novel Point of Care Diagnostics to Detect SARS-CoV-2
Danilo Tagle, Director, Office of Special Initiatives, National Center for Advancing Translational Sciences at the NIH (NCATS), United States of America

The National Institutes of Health (NIH) launched the Rapid Acceleration of Diagnostics (RADx) initiative to meet the needs for COVID-19 diagnostic and surveillance testing, and also to speed its innovation in the development, commercialization, and implementation of new technologies and approaches. The RADx Radical (RADx-rad) initiative is one component of the RADx program which focuses on the development of new, or non-traditional applications of existing approaches, to enhance their usability, accessibility, and/or accuracy for the detection of SARS-CoV-2.  This presentation will elaborate on two RADx rad programs led by the National Center for Advancing Translational Sciences on 1) pivoting technologies being developed for the isolation of exosomes towards screening and detection for SARS-CoV-2 viral infection due to the similar physical and chemical properties between exosomes and SARS-CoV-2 virus; and 2) developing novel biosensing capabilities using electronic nose technologies to detect unique signatures of volatile organic compounds (VOCs) of those with COVID-19 (Screening for COVID-19 by Electronic-Nose Technology (SCENT)).

Managing COVID Pandemic Using Rapid Testing Systems: An Austrian Perspective
Peter Ertl, Professor of Lab-on-a-Chip Systems, Vienna University of Technology, Austria

The incidence of viral distribution and infection has soared over the past decades due to population growth and increased travel, resulting in a global pandemic caused by SARS-CoV-2 viral outbreak. As a consequence, rapid detection and identification of viral infections is a pressing human health issue. Faster, more accurate diagnosis will benefit health care systems, in particular by significantly reducing time-to-result and providing better more reliable epidemiological data that can be used for infectious disease control. In course of the present presentation current Covid-19 test kits are reviewed and evaluated for point-of-care and on-site applications. Additionally, our efforts to develop a self-powered sensing solution combining liquid handling, microbatteries, optical read out unit microsensor arrays on a fully integrated and stand-alone lab-on-a-chip system will be discussed.

Microfluidic Diagnostic Technologies for Home-based Healthcare
Paul Yager, Professor, Department of Bioengineering, University of Washington and CSO, UbiDX, Inc., United States of America

For over a century, testing of human samples for acute and chronic diseases has been performed in centralized laboratories by trained technicians or now by large robotic instruments capable of batch processing hundreds of tests.  Since 2008 the Yager lab at UW has, under support of NIH, NSF, DARPA, the US Army and DTRA, focused on low-cost point-of-care biomedical diagnostics using two-dimensional porous networks (“paper microfluidics") for ultra-low-cost point-of-care pathogen identification.  Novel approaches to both on-device nucleic acid amplification and sensitive protein detection were developed and reduced to practice.  In the last decade there has been increasing interest in wearable sensors, and continuous monitoring. The COVID-19 pandemic opened up markets for rapid home testing for viruses, and exposed many people to the long-term possibilities for medical testing at home.  Like many of our colleagues, for the last 2 years (under support of WRF and an Emergent Ventures Rapid Grant), our lab has pivoted to address the pandemic by focusing on a respiratory pathogen panel that incudes SARS-CoV-2. The goal is a rapid semiquantitative validated highly-sensitive multiplexed nucleic acid test using isothermal amplification that can be stored for months at room temperature, but deliver results to an untrained home user (and perhaps also to public health authorities) from a nasal swab within 30 minutes.  We will show our latest results. The ability to detect and quantify a wide range of pathogens within an hour of sample acquisition opens up a range of health monitoring opportunities.  By coupling low-cost disposables with an optical reader, it is possible to have a home-based system to detect a wide of range of conditions beyond acute infections, allowing putting an integrated system for health maintenance in the home (or any POC setting) at low cost.  This approach is being commercialized by a new company, UbiDX.

Why Some Diagnostics Technologies Succeed While Others Fail: 28 Case Studies
Mickey Urdea, Founding Partner & Principal, Halteres Associates, United States of America

Over the last 20 years, Halteres has had the opportunity to work with many diagnostic technology companies (over 200 startups, many large multinational manufacturers) and their investors (angels, venture capitalists, granting agencies, NGOs). In that period, several diagnostics companies that initially appeared to be on a path to success ultimately failed. In 2015, the Bill and Melinda Gates Foundation asked Halteres to conduct a study to help them understand why some diagnostics companies fail and others succeed. For that purpose, we identified 28 diagnostics companies to include in a systematic study. We sought out and interviewed a number of experts from the investment community, company management teams from successful and failed companies and our Halteres Associates, most of whom have worked in diagnostics companies in various capacities. There were many insights shared and recorded.

The 28 diagnostics companies were classified into one of three groups: 1) “Successes” were defined as those companies that had reached commercial sustainability; 2) “Failures” were either out of business entirely or had their assets sold for small sums at the time of the study; and, 3) “Zombies” indicated companies that we felt were likely to eventually fail. Since the initial study was completed, 7 of the 8 Zombies identified were out of the business by the 4th quarter of 2021.  

The 28 companies were assessed based upon 5 phases of growth and the key objectives required to be successful in each phase. Successes tended to check all of the boxes, while Failures tended to fall short at more than one point, but typically one item appeared to be the most significant problem. Most Failures made early mistakes that resulted in company closure, but in other cases Failures managed to stay in business for many years. Most Zombies were rather long lived (~5-10 years).

We identified a number of best practices used by Successes that our interviewees and we felt could have saved the companies that failed. These factors will be presented and discussed.