Point-of-care diagnostics for infectious diseases: From methods to devices

Abstract

The current widespread of COVID-19 all over the world, which is caused by SARS-CoV-2 virus, has again emphasized the importance of development of point-of-care (POC) diagnostics for timely prevention and control of the pandemic. Compared with labor- and time-consuming traditional diagnostic methods, POC diagnostics exhibit several advantages such as faster diagnostic speed, better sensitivity and specificity, lower cost, higher efficiency and ability of on-site detection. To achieve POC diagnostics, developing POC detection methods and correlated POC devices is the key and should be given top priority. The fast development of microfluidics, micro electro-mechanical systems (MEMS) technology, nanotechnology and materials science, have benefited the production of a series of portable, miniaturized, low cost and highly integrated POC devices for POC diagnostics of various infectious diseases. In this review, various POC detection methods for the diagnosis of infectious diseases, including electrochemical biosensors, fluorescence biosensors, surface-enhanced Raman scattering (SERS)-based biosensors, colorimetric biosensors, chemiluminiscence biosensors, surface plasmon resonance (SPR)-based biosensors, and magnetic biosensors, were first summarized. Then, recent progresses in the development of POC devices including lab-on-a-chip (LOC) devices, lab-on-a-disc (LOAD) devices, microfluidic paper-based analytical devices (μPADs), lateral flow devices, miniaturized PCR devices, and isothermal nucleic acid amplification (INAA) devices, were systematically discussed. Finally, the challenges and future perspectives for the design and development of POC detection methods and correlated devices were presented. The ultimate goal of this review is to provide new insights and directions for the future development of POC diagnostics for the management of infectious diseases and contribute to the prevention and control of infectious pandemics like COVID-19.

Keywords: Biosensor; COVID-19; Device; Infectious disease; Point-of-care.

Graphical abstract

Scheme 1

Schematic illustration of point-of-care diagnostics for infectious diseases.

Fig. 1

(A) Schematic illustration of MoS₂ NSs based biosensor for the POC diagnosis of chikungunya virus (a) Screen printed gold electrode (SPGE). (b) Stepwise representation of the fabrication of SPGE with MoS₂ nanosheets, probe DNA and target DNA. (c) Interaction of working electrode (Au) of SPGE and MoS₂ shows strong affinity between Au (SPGE) and S (MoS₂). (d) MoS₂ interacts with probe DNA via Vander Waals forces. (e) Principle for the detection of hybridization of target DNA via redox hybridization indicator, i.e., methylene blue. Reproduced with permission from Ref. Copyright 2018, Springer Nature. (B) Schematic construction representation of the impedimetric label-free immunosensor based on an anti-NS1 modified gold electrode for POC dengue diagnosis. Reproduced with permission from Ref. Copyright 2015, Elsevier. (C) Schematic of the potentiometric sensing device, consisting of two parts: a sensor part for signal generation and a transducer part for signal amplification and readout. Reproduced with permission from Ref. Copyright 2016, Elsevier. (D) Schematic of graphene field-effect transistors (GFETs) nano-biosensor conjugated with single-chain variable fragment (scFv) antibodies for Lyme disease diagnosis. (a) Photograph of a sensor array with 100 GFET devices. (b) Optical micrograph of a GFET channel with dimension of 100 μm × 10 μm, connected to source and drain electrodes highlighted in yellow. The light purple region is the 285 nm thick SiO₂ substrate, while the darker purple region is the graphene channel. (c) Schematic of a GFET functionalized with Lyme disease scFv through a 1-pyrenebutyric acid N-hydroxysuccinimide ester linker, with the bound antigen. Reproduced with permission from Ref. Copyright 2020, IOP Publishing.

Fig. 2

(A) Schematic illustration of “Signal-on” fluorescence detection principle based on Qdot-aptamer conjugates and 3D nanoporous photonic crystal. (a) Loading the prepared quenched Qdot-aptamer conjugates (i.e., “OFF” state) for H1N1 virus detection in aerosol spray. (b) Capturing airborne H1N1 virus by aerosol spray and recovering Qdot signals by releasing G-DNA and preferred aptamer-virus binding (i.e., “ON” state). (c) Visualization of virus detection by enhanced Qdot signal owing to the emission light guide in 3D photonic crystals. Reproduced with permission from Ref. Copyright 2018, the Royal Society of Chemistry. (B) Schematic illustration of “Signal-off” fluorescence immunoassay for the detection of AIV. Reproduced with permission from Ref. Copyright 2012, Elsevier.

Fig. 3

(A) Schematic illustration of (a) the synthesis of Au-Van SERS tags, (b) the synthesis of aptamer-modified Fe₃O₄@Au MNPs, and (c) the operating procedure for S. aureus detection via the dual-recognition SERS biosensor. Reproduced with permission from Ref. Copyright 2019, Elsevier. (B) Schematic illustrations of diagnostic process for respiratory bacterial DNA using paper-based SERS substrate. In the presence of target, EvaGreen dye intercalation is dominant in DNA structure while in the presence of non-target or no-target, majority of EvaGreen is adhered on the hot-spots area of the AgNWs. The diagnosis can be made by comparing the Raman intensity between the test line and the control lines. Reproduced with permission from Ref. Copyright 2021, Elsevier.

Fig. 4

(A) The principle of the proposed colorimetric biosensor for rapid detection of E. coli O157:H7 based on gold nanoparticle aggregation and smart phone imaging. Reproduced with permission from Ref. Copyright 2019, Elsevier. (B) Schematic illustration of stochastic DNA dual-walkers for colorimetric detection of bacteria. Reproduced with permission from Ref. Copyright 2020, American Chemical Society.

Fig. 5

Schematic illustration of one step multiplex RT-PCR and chemiluminescence detection of multiple viruses. Reproduced with permission from Ref. Copyright 2017, the Royal Society of Chemistry.

Fig. 6

(A) Schematic representation of SPR biosensor for POC detection of HIV. (a) Schematic illustration of the preparation of DDTs nanostructure; (b) Schematic representation of SPR biosensing strategy for HIV-related DNA detection based on ESDRs and DDTs nanostructure. Reproduced with permission from Ref. Copyright 2018, Elsevier. (B) Schematic representation of the detection mechanism of dengue virus serotypes by AuNPs and hairpin ssDNA-CdSeTeS quantum dots. (a) Probe design for DProbe 1 and 2 and functionalized AuNPs. (b) Identification and fluorometric enhancement for dengue virus 1/3 serotype and quenching for dengue virus 2/4 serotype depending on the distance between the nanocomposite of AuNP-dsDNA-CdSeTeS. Reproduced with permission from Ref. Copyright 2020, the Royal Society of Chemistry. (C) Schematic of Portable plasmonic platform for pathogen detection and quantification. Reproduced with permission from Ref. Copyright 2015, Springer Nature.

Fig. 7

(A) Schematic of Z-Lab diagnosis platform and magnetic sandwich assay mechanism. (a) Real-time data can be collected and transmitted to a smartphone, a tablet, a laptop and a desktop computer. (b) The Z-Lab platform consists of a plastic cartridge, an electrical interface connecting the electrodes from GMR chip to the circuit board, and a handheld device. (c) Schematic of the GMR chip. (d) Schematic of the magnetic sandwich assay. (e) Real-time binding curves of targeted binding. Reproduced with permission from Ref. Copyright 2017, American Chemical Society. (B) Schematic of a wash-free magnetic bioassay based handheld GMR biosensors for POC detection (a) One-step wash-free magnetic bioassay based on a sandwich assay structure. (b) Photograph of one Z-Lab diagnosis platform. (i) disposable plastic cartridge; (ii) cartridge shell; (iii) Helmholtz coil with ferrite core; (iv) card edge connector; (v) microcontroller; (vi) UART to Bluetooth and USB; (vii) power supply; (viii) current source Helmholtz coil driver. (c) The circuit schematic of Z-Lab. Reproduced with permission from Ref. Copyright 2019, Frontiers. (C) Schematic of the MPS biosensor for POC diagnostics (a) Schematic view of MPS system setups. (b) and (c) are the third and the fifth harmonics along varying driving field frequencies (only samples I, VIII, and IX are plotted) collected by the MPS system. (d) Boxplots of the harmonic ratios (R35) collected from samples I, VIII, and IX. Reproduced with permission from Ref. Copyright 2020, American Chemical Society.

Fig. 8

(A) Schematic illustration of assembly of multifunctional 3D printed reactor array for rapid POC detection of Plasmodium falciparum gDNA. Reproduced with permission from Ref. Copyright 2018, Elsevier. (B) Schematic of the metal-oxide-semiconductor LOC platform integrated ISFETs to facilitate direct chemical-to-electronic sensing and LAMP for malaria detection. (a) Cross-section of an ISFET fabricated in unmodified CMOS technology and equivalent circuit macromodel. (b) Schematic of the pixel circuit implemented as a source follower configuration where changes in V_out reflect changes in pH. (c) Setup showing the LOC platform including a motherboard printed circuit-board that facilitates data readout, a cartridge PCB hosting the microchip and microfluidic chamber, the microchip including an array of 4096 ISFET sensors and an external thermal controller. (d) Cross-section illustration of the LOC platform showing the reaction interface. Reproduced with permission from Ref. Copyright 2019, Elsevier. (C) Schematic illustration of film-based immunochromatographic microfluidic device for malaria diagnosis. (a) An exploded view of the immunochromatographic microfluidic device. (b) Schematic illustration of the malaria parasite capture antibody immobilization procedure on the polycarbonate film. (c) The structure of the immunochromatographic microfluidic device. (d) Photograph of the IMD with a paper case. Reproduced with permission from Ref. Copyright 2019, Springer Nature.

Fig. 9

(A) Schematic of the handheld smartphone-coupled LOC device for the detection of HRP-II antigen. (a) Isometric view of a rendering of the handheld device, less the case. (b) Top view of the handheld device. (c) Exploded view of the entire device. (d) Photograph of actual device with an iPhone 4 installed. Reproduced with permission from Ref. Copyright 2014, SAGE Publishing. (B) Overview of the smartphone-based POC testing analyzer. (a) Functional concept of the MCFA lab chip with on-chip reservoirs in operation sequence to implement chemiluminescence based sandwich ELISA, (b) Schematic of the designed MCFA chip with detailed labeling of the microfluidic components and (c) Schematic of the developed smartphone-based POC testing analyzer. Reproduced with permission from Ref. Copyright 2020, Springer Nature.

Fig. 10

(A) Schematic illustration of the Lab-on-a-Film disposable device for the POC detection of MDR-TB from sputum extracts. Reproduced with permission from Ref. Copyright 2019, the Royal Society of Chemistry. (B) Schematic illustration of the benchtop automated sputum-to-genotype system using the LFA for the detection of MDR-TB. (a) Photograph of the interior of the analyzer depicting the MagVor for lysis and homogenization, the TruTip for purification, the deepwell plate so that all liquids are part of the consumable, pipetting station, the LFA, the thermal cycler, and the imager. (b) Layout of the consumable for six samples in which the following steps occur. (c) Illustration of the LFA on the system with the thermal cycler in the (1) “up” (disengaged) position, (2) in the “down” (engaged) position, and (3) with the imager capable of individually imaging and analyzing each array of gel elements. Reproduced with permission from Ref. Copyright 2020, American Chemical Society.

Fig. 11

(A) Schematic of a COC based LOC device using a ZFP array for POC detection of E. coli O157:H7. (a) An image of the COC array spot chip. (b) A schematic diagram of the ZFP array on the COC chip. Reproduced with permission from Ref. Copyright 2018, the Royal Society of Chemistry. (B) Schematic illustration of the SIMPLE chip for low cost, quantitative, and portable nucleic acid testing. (a) Samples can be simply dropped into the inlet for automatic sample preparation with minimal handling and no external pumps or power sources. (b) The end-point isothermal digital amplification of nucleic acid was done (RPA) by incubating the chip on a reusable heat pack. Scale bar, 2 mm. (c) Dye-loaded chip for visualization of microchannels. (d) Digital microfluidic patterning enables reagent patterning with common laboratory equipment. (e) Side view of the digital plasma separation design. (f) The vacuum battery system frees the chip from external pumps or power sources for pumping. Reproduced with permission from Ref. Copyright 2017, AAAS.

Fig. 12

(A) Schematic of an automated microfluidic sample preparation multiplexer (SPM) device combined with a sensitive liquid-core antiresonant reflecting optical waveguide biosensor chip for Ebola detection. (a) Design of the SPM with six incubation reservoirs for target preparation. (b) Photograph of the SPM. (c) Schematic of the solid-phase extraction process and assay. Reproduced with permission from Ref. Copyright 2017, Elsevier. (B) Schematic of (a) Design of the SPM for on-chip solid-phase extraction with 80 incubation reservoirs. (b) Photograph of the SPM. (c) Schematic of the on-chip solid phase extraction experiment. Reproduced with permission from Ref. Copyright 2017, American Chemical Society. (C) Schematic of automated CRISPR microfluidic chip for Ebola virus detection. (a) Design of the automated CRISPR microfluidic chip. (b) Blow up of design of the fluidic layer. (c) Open (left) and closed (right) states of a microvalve. (d) Design of a benchtop fluorometer system integrated with a microfluidic device for in situ virus sensing. (e) Photograph of chip and detection system. Reproduced with permission from Ref. Copyright 2019, American Chemical Society. (D) LOC design for the RT-PCR: (a) design of the polymer RT-PCR LOC; (b) photograph of fabricated RT-PCR LOC including 5 different chambers; and (c) embedded micro pinch valves using silicone tubes. Reproduced with permission from Ref. Copyright 2008, the Royal Society of Chemistry. (E) Schematic illustration of the assembled nucleic acid cassette. Reproduced with permission from Ref. Copyright 2010, Springer. (F) Self-digitization chip for HIV detection. (a) Schematic of the self-digitization chip. 16 × 64 array of 6.5 nL microwells connected by channels is embedded in PDMS and covered with a PDMS-coated glass slide. (b) Photograph of the self-digitization chip. Reproduced with permission from Ref. Copyright 2018, the Royal Society of Chemistry.

Fig. 13

Schematic illustration of the smartphone-coupled LOC device utilizing quantum dot barcodes. (A) Assay involves the addition of patient samples to a chip coated with microbeads, which are optically barcoded by quantum dots and are coated with molecules that recognize a target analyte. (B) Typical microwell chip containing different barcodes in each well. (C) Smartphone camera captures the image of four different quantum dot barcodes arrayed on the surface of the chip. (D) Two excitation sources excite the quantum dot barcoded chip independently. (E) Image of the smartphone device. Reproduced with permission from Ref. Copyright 2015, American Chemical Society.

Fig. 14

Schematic illustration of real-time fluorescence LOAD nucleic acid testing device for malaria detection. (A) Exploded view of the device, showing the assembly of various components. (B) Schematic of the assembled device and the quadplex microfluidic reagent compact disc. The form factor of the analyzer is palm-sized. The reagent compact disc is secured to the spindle platter. A real-time fluorescence sensing scheme is integrated on the analyzer. (C) Workflow of the device. Reproduced with permission from Ref. Copyright 2018, Elsevier.

Fig. 15

(A) Schematic illustration of the LOAD device for POC detection of Salmonella. (a) Expanded view of the LOAD showing top and bottom plates made of polycarbonate, strip sensors, adhesive layer, and the metal heater. (b) Top view of a section of the disc featuring the chambers for cell lysis, isothermal amplification, metering, dilution, and detection. (c) Schematic illustration of the experimental setup. Reproduced with permission from Ref. Copyright 2014, American Chemical Society. (B) Schematic illustration of the LOAD device. (a) The function components of the LOAD. (b) Assembly of the LOAD. (c) Photograph of the assembled LOAD. Reproduced with permission from Ref. Copyright 2016, the Royal Society of Chemistry. (C) Schematic illustration of the integrated centrifugal disc. (a) The function components of the integrated centrifugal disc. (b) A digital image of the disc. (c) Components of the centrifugal microdevice. Reproduced with permission from Ref. Copyright 2019, Elsevier.

Fig. 16

The Dx-FS as a POCT device for low-resource settings. (A) Fidget spinner (left) and Dx-FS (right). (B) Sample enrichment (urine sample preparation) and UTI diagnostics performed by a Dx-FS. (C) Design of the Dx-FS with labeled parts. (D) Images from a high-speed video showing the operation of a Dx-FS: the device was (i) hand-spun, (ii) spun for 1 min and (iii) stopped. The areas colored in red denote the liquid flow during the process. (E) Angular rotational frequency of the Dx-FS versus time. Reproduced with permission from Ref. Copyright 2020, Springer Nature.

Fig. 17

(A) Schematic illustration of the sample-to-result LOAD platform. (a) Image of the platform appearance. (b) Photograph of the internal modules. (c) Schematic diagram of the main modules in the platform. (d) Schematic diagram of the non-contact heating and the optical module with the dichroic beam splitter. (e) Photograph of the assembled disc mounted on the rotary axis. (f) Assembly of the disc. (g) Design of the diagnostic disc. Reproduced with permission from Ref. Copyright 2018, Elsevier. (B) Schematic illustration of the DRA-CMP for HBV detection. (a) Exploded view of the chip contains four layers. (b) Schematic illustration of the flow control module consisting of a DRA-CMP and a disc. (c) Schematic illustration of the waste chamber of the disc. (d) Picture of the disc. (e) Schematic of the microfluidic layout for sample-to-result HBV DNA detection from whole blood. Reproduced with permission from Ref. Copyright 2019, American Chemical Society.

Fig. 18

(A) Schematic of paper-based multiplexed LAMP detection of malaria in blood. (a) Foldable paper devices: dark areas are printed with hydrophobic wax. The device consists of five panels (1–5) folding onto each other, and a plastic cover for LAMP processing to avoid evaporation. (b) The design incorporates alignment marks on two corners to assign the results. (c) Illustration of the extraction process. (d) By folding the device, the sample is transferred to the LAMP spots where the reaction is carried out. (e) The signal is read out using a UV flashlight (365 nm). Reproduced with permission from Ref. Copyright 2016, Wiley. (B) Illustration of the main microfluidic technologies. The complexity/cost decreases from left to right. Reproduced with permission from Ref. Copyright 2014, IOP Publishing. (C) Schematic illustration of laser-patterned paper-based device. (a) Schematic of the laser-based direct-write setup. (b) Schematic of the laser direct-write fabricated three-layer paper device for bacteria identification and antibiotic-resistance testing. Reproduced with permission from Ref. Copyright 2020, Elsevier.

Fig. 19

Schematic of the integrated lateral flow device on a rotary microfluidic system for POC colorimetric detection of Salmonella Typhimurium and Vibrio parahaemolyticus. (A) A digital image of the integrated rotary microdevice (B) Schematic illustration of the integrated rotary microdevice for the DNA extraction, the LAMP reaction, and the lateral flow strip detection. (C) Schematic illustration of the solid phase DNA extraction unit and the fluorescence images of the FAM-labeled DNA adsorbed glass microbeads (a), the LAMP amplification of target DNA (b), and (c) the lateral flow strip detection. Reproduced with permission from Ref. Copyright 2017, Elsevier.

Fig. 20

Schematic of a disposable and integrated lateral flow device for nucleic acid extraction, amplification and detection. (A) The different functional modules of the device, including nucleic acid extraction, amplification by the battery heat blocker and lateral flow detection. (B) The substrate and a bridge that was used to separate the upper layer copper sheet from the bottom layer to prevent the lysis buffer and washing buffer from flowing to the dry powder paper. (C) The top cover of the integrated lateral flow device. (D) The integration platform of the different functional modules and the substrate. (E) The model of this device. Reproduced with permission from Ref. Copyright 2017, the Royal Society of Chemistry.

Fig. 21

(A) Schematic illustration of the configuration and (B) the measurement principle of the SERS-based lateral flow device for quantification of HIV-1 DNA. (C is the control line and T is the test line). Reproduced with permission from Ref. Copyright 2016, Elsevier.

Fig. 22

(A) Schematic of smartphone-coupled fluorescent lateral flow immunoassay device. (a) Schematic description of a smartphone-based fluorescence detector with a reflective light concentrator module. (b) Schematic of a fluorescence detector flow strip for the detection of AIVs, whose fluorescence signal is measured by the smartphone-based diagnostic device. (c) The detection processes of this device. Reproduced with permission from Ref. Copyright 2016, Ivyspring International Publisher. (B) Overview of the smartphone-coupled rapid dual fluorescent lateral flow immunoassay based diagnostic system. (a) Schematic presentation of the multiplexed lateral flow strip with two simultaneous conjugates. (b) Schematic representation of the smartphone-based fluorescence detector with a reflective light concentrator module and two emission filters. Reproduced with permission from Ref. Copyright 2018, Ivyspring International Publisher.

Fig. 23

The schematic for the (A) integrated CF-PCR-electrophoresis microfluidic chip and the all-in-one device. The photos of the (B) microfluidic chip, (C) prototype system, and (D) all-in-one device. Reproduced with permission from Ref. Copyright 2019, the Royal Society of Chemistry.

Fig. 24

(A) Schematic illustration of the handheld DMF LAMP device for the DNA detection of blood parasite Trypanosoma brucei. (a) 3D schematic of the components of the device. DC: direct current. (b) Schematic of the LAMP reaction and endpoint SYBR Green I denotation of positive LAMP products. (c) Side view of the DMF chip. (d) Droplet actuation and heating control electronics. (e) Schematic of the naked-eyed visualization of the LAMP results. Reproduced with permission from Ref. Copyright 2019, Springer Nature. (B) Schematic illustration of the water-activated, self-heating, non-instrumented cartridge based LAMP device. (a) Exploded view and a photograph (b) of the water-activated, self-heating, non-instrumented cartridge for isothermal amplification of nucleic acids. Reproduced with permission from Ref. Copyright 2011, the Royal Society of Chemistry.

Fig. 25

(A) Exploded view of the self-driven microfluidic chip consisting of a PDMS microfluidic structure layer, a hydrophilic film, a PDMS hydrophobic layer, and a glass substrate. (B) A photograph of the chip. (C) Schematic illustration of the chip design. The area enclosed by the red dotted line represents the LAMP reaction module (module B), with the other area being used for sample treatment (module A). (D) Illustration of the portable system composed of two stepping motors, two sets of gears, two photo-interrupters, a punching-press mechanism, an Arduino-based microcontroller circuit, a thermal control module, a color sensor, and a microfluidic chip. (E) Experimental workflow of a sample-to-answer, potable platform for rapid pathogen detection. Reproduced with permission from Ref. Copyright 2019, the Royal Society of Chemistry.

Fig. 26

Schematic illustration of the portable LAMP based device called TINY for isothermal nucleic acid quantification with power from electricity, sunlight or a flame. (A) TINY is portable and easily carried in one hand, which is far smaller than the GeneXpert IV by Cepheid (footprint outlined by the dark purple box), or the ViiA 7 Real-Time PCR System by Thermo Fisher Scientific (light purple box) (B). (C) TINY heated by a Bunsen burner through an opening in the bottom of the system. (D) TINY heated via electricity, using an integrated cartridge heater. (E) TINY heated via concentrated sunlight at the infectious diseases institute in Uganda. (F) A photograph of the measurement unit separated from the temperature-regulation unit. (G) A cross-section of the measurement unit. (H) LEDs are placed on the bottom side of the top PCB. (I) Looking down into the TINY system with the solar absorption plate removed. (J) A cross-section of the temperature-regulation unit. Reproduced with permission from Ref. Copyright 2018, Springer Nature.