Chapter 15 Lab-on-a-Chip (LOC) Immunoassays Sandeep K. Vashist1, John H.T. Luong 1IDS Immunodiagnostic Systems Deutschland GmbH, Frankfurt am Main, Germany;2 University College Cork, Cork, Ireland 1. INTRODUCTION The outreach of healthcare has been obstructed by the lack of resources, insufficient healthcare professionals, and unaffordable costs of clinical diagnostics. Therefore, there are increasing efforts toward the development of low-cost and easy-to-use in vitro diagnostic (IVD) platforms for the diagnosis of diseases in the developing countries and remote settings. To date, there are numerous developments in the field of lab-on-a-chip (LOC) technologies in the last two decades. Cost-effective LOC platforms are diversified based on immunobiosensing concepts, microfluidic (MF) protocols, materials, reagent storage and release mechanisms, and low-cost readout devices. The current generation of LOC platforms and the rapid improvements in immunoassays (IAs) and complementary technologies are paving the way to highly advanced LOC IAs to target point-of-care testing (POCT). The evolving trend is strongly inclined to the development of LOC IAs for personalized healthcare moni- toring and management. The innovative advances made in cellphone (CP) detection-based bioanalytical technologies have further started a new era of mobile healthcare. Considering over 7 billion CP users with 70% in the developing countries, the interface of LOC IA with CPs is indeed revolu- tionary, enabling personalized POCT and better healthcare management [1,2]. CPs would provide spatiotemporal tagged data to offer real-time healthcare monitoring and management. The mobile health solutions market is growing at a rapid pace and is expected to reach USD 90.5 billion by 2022 [3]. During the recent years, several LOC IAs and devices have been successfully imple- mented in central laboratories and physician office laboratories for POCT. Apparently, LOC IAs play a critical role in centralized and decentralized, remote, and personalized settings. Their deployment would be immensely useful in epidemics and emergencies that require immediate detection of analytes at the point of need. Handbook of Immunoassay Technologies. https://doi.org/10.1016/B978-0-12-811762-0.00015-3 Copyright @ 2018 Elsevier Inc. All rights reserved. 415
416 Handbook of Immunoassay Technologies LOC-based POCT would enable rapid and cost-effective clinical diagnosis using minimal sample volumes [4] at the bedside of a patient, in a physician's office, at home, or in paramedical support vehicles, as well as secondary and tertiary care settings. It would provide the results just within a few minutes using a highly simplified protocol with one or two process steps to process whole blood, serum, plasma, urine, or other samples. The point-of-care (POC) diagnostics' global market will reach USD 37 billion by 2021 [5]. India and China would account for the most predominant market share due to enormous populations with increased prevalence of chronic and infectious diseases. Consequently, LOC IAs and POCT devices must be affordable for those at risk of infection or chronic diseases. They must also be robust and unrefrigerated in addition to providing the desired sensitivity and specificity, minimal steps, and short turnaround time. This chapter provides an overview of various LOC IAs along with the global trend toward next-generation POCT, the challenges, and outlook. Table 15.1 summarizes