Platform Technologies for In vitro Point-of- Care Diagnostics
Abstract
In vitro diagnostic (IVD) tests are critical for making informed clinical decisions. These
tests are performed outside the body using specimens such as blood, sputum, saliva, and
urine. IVD tests are usually performed at centralized labs with complex and expensive
instrumentation, and associated protocols. There are only a few commercially available
point-of-care (POC) devices for performing IVD Tests. This thesis presents platform
technologies for POC testing of three categories of IVDs: Clinical Biochemistry,
Immunodiagnostics, and Molecular diagnostics. Additionally, a Biosafety Level 2+ (BSL-
2+) Mobile Laboratory was designed & developed for testing of infectious diseases at the
point-of-need.
Clinical biochemistry tests are quantitative tests that measure the concentration of
biochemicals in body fluids. Most clinical biochemistry tests involve the testing of serum.
A POC serum separation device from micro-volumes of blood using an air-displacement
pipette and a chemical-preloaded disposable pipette-tip cartridge is introduced in Chapter-
2. To address the issue of reagent stabilization and room-temperature storage, trehalosebased
enzyme reagent matrix (TERM) cartridge with dried reagents was developed. The
cartridge was tested for triglycerides measurement in blood and found to offer good shelflife.
In addition, the development of reagent kits for conducting sickle-cell disease
confirmatory test at point-of-need was reported. Finally, as an alternative to conventional
biochemical analyzers, a portable multi-spectral absorbance reader capable of detecting
the results at POC of a wide range of clinical biochemical assays was developed and
validated.
Immunodiagnostics includes tests that can detect and quantify antigens and
antibodies in a sample. Chapter-3 of the thesis proposes the development of platform
technologies in this category based on introducing innovative (i) protocols and (ii)
processes: (i) Counting target CD4+ T-Cells in blood was demonstrated using anti-CD4
antibodies conjugated to superparamagnetic iron oxide nanoparticles (SPIONs) and a
commercially available haematology analyser. (ii) A bare fibre Bragg grating (bFBG)
sensor-based technique is developed for pathogen detection, and demonstrated its ability in
detecting E. coli in water by coating anti-E. Coli antibodies onto the bFBG sensor.
Molecular diagnostics comprises of techniques that can detect the presence or
modification of nucleic acid (DNA/RNA). These tests usually require sophisticated and
iv
expensive instruments. To address this issue, Chapter-4 reports the development of
Portable PCR System: i) Isothermal Amplification Device (LAMP assays), ii) Handheld
Thermal Cycler (tested for HCV & Dengue), and iii) Fluorescence Reader (tested for
CoViD-19). In Chapter-5, a mobile laboratory for infectious diseases testing and reporting
(MITR Lab) was conceptualized, designed, fabricated, and found to offer 100% match
with static lab results in testing CoViD-19. The MITR lab is the first ICMR approved
Mobile BSL2+ lab for COVID-19 testing and aided in conducting few lakh tests during the
past one year.
All the technologies developed as part of the thesis are validated with clinical
samples and showed sensitivity and specificity above 90%. These innovative, affordable
platform technologies are expected to create huge social impact by providing timely
diagnoses at the point-of-need.