Abstract
Point-of-care (POC) diagnostics are tests which can be performed at or near the site of a patient to produce results in a timely manner, improving on conventional tests which are mostly confined to a central laboratory. They are used in many different applications including diagnosing highly infectious diseases [1], providing routine daily monitoring of diseases such as diabetes [2], to assess the impact of treatments which includes oral anticoagulants [3] and for at home-testing to determine pregnancy [4].There are many different types of POC devices and platforms. Due to the COVID-19 pandemic, paper-based lateral flows have become one of the most well known [5]. Microfluidic devices are also routinely used to provide on-the-spot answers [6]. The test also does not necessarily have to use a device and could be as simple as mixing of reagents and samples to produce a solution-based platform. It is usually designed to detect the presence of a biomarker using different chemistries such as the polymerase chain reaction (PCR), immunoassays or enzymatic tests. Labeling molecules are also used which can then be detected visually or with a read-out instrument, to give either a simple yes/no answer or provide a quantitative result.
To be seen as a viable POC diagnostic, the World Health Organization (WHO) has set a list of objectives to which the test should adhere. By following the WHO ASSURED criteria, the test must be ‘Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment-free and Deliverable’ [7]. The hardest criteria to achieve is ‘equipment-free’ as many POC tests depend on a read-out instrument to quantify the concentration of analyte present. Although the read-out instrument is usually unavoidable, when selecting it, it should be portable, provide decision support, connect to other information systems and have a simple interface between the POC test and the instrument to retain a straightforward, easy-to-use POC diagnostic test [8]. A variety of read-out instruments are used to detect the labeling entity including fluorescence readers [9], ultraviolet-visible spectrometers [10] and potentiostats [11]. If nanoparticles are used to label, Raman spectrometers can be used as the read-out instrument to provide sensitive detection of biomarkers by assessing the surface-enhanced Raman scattering (SERS) signal from the device [12]. This chapter will review how SERS has been combined with POC diagnostic tests, the efforts being made to change the opinion of SERS being a lab-based technique and how it can become one of the gold standard methods used in POC testing.
To be seen as a viable POC diagnostic, the World Health Organization (WHO) has set a list of objectives to which the test should adhere. By following the WHO ASSURED criteria, the test must be ‘Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment-free and Deliverable’ [7]. The hardest criteria to achieve is ‘equipment-free’ as many POC tests depend on a read-out instrument to quantify the concentration of analyte present. Although the read-out instrument is usually unavoidable, when selecting it, it should be portable, provide decision support, connect to other information systems and have a simple interface between the POC test and the instrument to retain a straightforward, easy-to-use POC diagnostic test [8]. A variety of read-out instruments are used to detect the labeling entity including fluorescence readers [9], ultraviolet-visible spectrometers [10] and potentiostats [11]. If nanoparticles are used to label, Raman spectrometers can be used as the read-out instrument to provide sensitive detection of biomarkers by assessing the surface-enhanced Raman scattering (SERS) signal from the device [12]. This chapter will review how SERS has been combined with POC diagnostic tests, the efforts being made to change the opinion of SERS being a lab-based technique and how it can become one of the gold standard methods used in POC testing.
Original language | English |
---|---|
Title of host publication | Raman Spectroscopy in Human Health and Biomedicine |
Editors | Hidetoshi Sato , Jürgen Popp , Bayden R Wood, Yukihiro Ozaki |
Place of Publication | Singapore |
Chapter | 7 |
Pages | 221-270 |
Number of pages | 50 |
DOIs | |
Publication status | Published - 31 Oct 2023 |
Keywords
- Raman spectroscopy
- point-of-care diagnostics
- surface-enhanced Raman scattering