Figure 1:
Figure 2:
![Sample preparation of nucleic acids in POCT. (A) Schematic diagram of the operation process of nucleic acid extraction and purification using MBs in one assay unit and the image of the chip [20]. (B) 3D Helmholtz coil active magnetic capture nucleic acid chip and device explosion diagram [24]. (C) A centrifugal microfluidic chip and its supporting automation platform [30]. (D) Chitosan and polydopamine modified magnetic beads and corresponding chip [31]. LAMP, Loop mediated adiabatic amplification; POCT, point-of-care testing.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/678caf4e082aa65dea3d247b/j_ijssis-2025-0014_fig_002.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251021%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251021T180156Z&X-Amz-Expires=3600&X-Amz-Signature=d4ddcbab36181513032eba92c9da575f8a8ea432ee7f1c00f0a39eed22c03bc2&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 3:
![Microfluidic chips and temperature control devices for ultrafast PCR. (A) Ultrafast PCR design and hardware device [56]. (B) Ultrafast PCR chip with 35 cycles in 1 min and fast rising and cooling device [57]. (C) Microfluidic chip to improve RTDs performance and the temperature control device [62]. PCR, polymerase chain reaction; RTDs, resistance temperature detectors.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/678caf4e082aa65dea3d247b/j_ijssis-2025-0014_fig_003.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251021%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251021T180156Z&X-Amz-Expires=3600&X-Amz-Signature=538e0dabe876c4e2a3ff55ce767d59ca8f610e2800040bf3992845547110b44f&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 4:
![Microfluidic chips and temperature control devices for LAMP. (A) Portable device for multichannel real-time nucleic acid detection [72]. (B) Schematic diagram of the principle of the microfluidic chip (a quarter of the disk chip) for the whole process detection and schematic diagram of the matching automatic detection platform [73]. (C) Schematic diagram of disk microfluidic chip based on LAMP and its supporting automatic detection platform [74]. LAMP, loop-mediated adiabatic amplification; LED, light-emitting diode.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/678caf4e082aa65dea3d247b/j_ijssis-2025-0014_fig_004.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251021%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251021T180156Z&X-Amz-Expires=3600&X-Amz-Signature=cca989638a18832991374dd3f97103a20eb7a64434f528ef7cf0cd00a4f9197f&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
Figure 5:
![(A) Schematic diagram of optical path of single channel fluorescent module: schematic diagram of optical path blue indicates excitation, and green indicates the fluorescence emitted by the sample [94]. (B) Schematic diagram of optical path of dual channel fluorescent module: two excitation lights (blue and yellow) and two emission lights (green and orange) form a confocal optical path with the help of four dichroic mirrors [93]. (C) The three-dimensional (3D) illustration of the fluorescence module in an exploded view, which includes metal shell, PCB, optical path cover, optical structure, and focus lens [93]. (D) Schematic diagram of single channel current-optical double negative feedback led drive circuit, including three parts: current feedback, light intensity feedback, and LED selection signal [94]. (E) Schematic diagram of single channel photoelectric processing circuit, including: TIA, filter, and A/D conversion [94]. (F) The schematic diagram of dual channel circuit can be divided into three parts: current feedback, light intensity feedback, and led selection [93]. A/D, analog-to-digital; LED, light-emitting diode; PD, photodiode; TIA, transimpedance amplifier.](https://sciendo-parsed.s3.eu-central-1.amazonaws.com/678caf4e082aa65dea3d247b/j_ijssis-2025-0014_fig_005.jpg?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Content-Sha256=UNSIGNED-PAYLOAD&X-Amz-Credential=AKIA6AP2G7AKOUXAVR44%2F20251021%2Feu-central-1%2Fs3%2Faws4_request&X-Amz-Date=20251021T180156Z&X-Amz-Expires=3600&X-Amz-Signature=280f31084afb198e5658a0e88839f615c03c257e7b45be6932d3911c64cbb614&X-Amz-SignedHeaders=host&x-amz-checksum-mode=ENABLED&x-id=GetObject)
PCR techniques applied in POCT devices
| Method | Advantage | Disadvantage |
|---|---|---|
| PCR | Low cost; complete standards; and the product is recyclable | The operation is cumbersome; low specificity and sensitivity; easy to be contaminated; and cannot perform quantitative analysis |
| qPCR | High specificity and sensitivity; quantitative analysis | High cost, nonrecyclable product; fluorescent probe or dye required |
| RT-PCR and RT-qPCR | Widely applicable and can be used for all types of RNA | RNA is easily degraded; additional reverse transcription steps are required |
| dPCR | Absolute quantification; extremely high sensitivity and specificity | Expensive cost; complex operation; and long-time consuming |
LAMP and PCR techniques in POCT devices
| LAMP | PCR | |
|---|---|---|
| Equipment | Constant temperature equipment | PCR amplifier, thermal cycler |
| Reaction process | One-step amplification | Cyclic amplification |
| Amplification temperature | Constant temperature (60–65°C) | Denaturation (95°C), annealing (50–60°C), polymerization (72°C) |
| Reaction time | 15–40 min | Depends on the temperature control rate of the thermal cycler |
| Primer design | 4–6 primers, high design difficulty | 2 primers, easy to design |
| Sensitivity | Higher sensitivity, but prone to false positives and more expensive | High sensitivity and strong specificity |
| Reagent prices | Higher sensitivity, but prone to false positives and more expensive | Cheap |