Portable point-of-care diagnostic devices: an updated review

Fluorophore and nanozyme-functionalized DNA walking: A dual-mode DNA logic biocomputing platform for microRNA sensing in clinical samples

Inspired by the programmability and modifiability of nucleic acids, point-of-care (POC) diagnostics for nucleic acid target detection is evolving to become more diversified and intelligent. In this study, we introduce a fluorescent and photothermal dual-mode logic biosensing platform that integrates catalytic hairpin assembly (CHA), toehold-mediated stand displacement reaction (SDR) and a DNA walking machine. Dual identification and signal reporting modules are incorporated into DNA circuits, orchestrated by an AND Boolean logic gate operator and magnetic beads (MBs). In the presence of bispecific microRNAs (miRNAs), the AND logic gate activates, driving the DNA walking machine, and facilitating the collection of hairpin DNA stands modified with FAM fluorescent group and CeO2@Au nanoparticles. The CeO2@Au nanoparticles, served as a nanozyme, can oxidize TMB into oxidation TMB (TMBox), enabling a near-infrared (NIR) laser-driven photothermal effect following the magnetic separation of MBs. This versatile platform was employed to differentiate between plasma samples from breast cancer patients, lung cancer patients, and healthy donors. The thermometer-readout transducers, derived from the CeO2@Au@DNA complexes, provided reliable results, further corroborated by fluorescence assays, enhancing the confidence in the diagnostics compared to singular detection method. The dual-mode logic biosensor can be easily customized to various nucleic acid biomarkers and other POC signal readout modalities by adjusting recognition sequences and modification strategies, heralding a promising future in the development of intelligent, flexible diagnostics for POC testing.

Validation of non-invasive point of care blood content analysis using the TensorTip™ MTX device: a method comparison study

OBJECTIVES

The TensorTip™ MTX is a non-invasive device designed to determine several physiological parameters with additional analysis of haemoglobin, haematocrit and blood gas analysis by interpreting blood diffusion colour of the finger skin based on spectral analysis. The aim of our study was to investigate the accuracy and precision of the TensorTip MTX in a clinical setting in comparison with routine analysis of blood samples.

METHODS

Forty-six patients, scheduled for elective surgery, were enrolled in this study. Placement of an arterial catheter had to be part of the standard of care. Measurements were performed during the perioperative period. The measurements obtained with the TensorTip MTX were compared with the results of routine analysis of the blood samples as a reference using correlation, Bland-Altman analysis and mountain plots.

RESULTS

No significant correlation was present in the measurements. Measurement of haemoglobin with the TensorTip MTX had a mean bias of 0.4 mmol/L, haematocrit's bias was 3.0 %. Bias of partial pressure of carbon dioxide and oxygen was 3.6 and 66.6 mmHg, respectively. Calculated percentage errors were 48.2 , 48.9, 39.9 and 109.0 %. Proportional bias was present in all Bland-Altman analyses. Less than 95 % of the differences fell within the pre-set limits of allowable error.

CONCLUSIONS

Non-invasive blood content analysis with the TensorTip MTX device is not equivalent to and did not correlate sufficiently with conventional laboratory analysis. None of the parameters measured showed results within the limits of allowable error. Therefore, the use of the TensorTip MTX is not recommended for perioperative care.

Portable biosensor-based oral pathogenic bacteria detection for community and family applications

Detection of oral pathogens is essential in the management of oral diseases, as their occurrence and progression are closely linked to an imbalance in these microorganisms. Detection techniques such as microbial cultures, enzyme-linked immunosorbent assays and polymerase chain reactions are highly dependent on complex testing procedures and specialized laboratory equipment, making prevention and early diagnosis of oral diseases difficult. To comprehensively implement oral disease prevention and early diagnosis in social groups, there is an urgent need for portable testing methods for oral pathogenic bacteria that can be applied in community and home settings. In this review, several common portable biosensors for pathogenic bacteria are first described. Based on the goal of achieving primary prevention and diagnosis of oral diseases, we elaborate and summarize portable biosensors for common oral pathogenic bacteria in terms of how to achieve portability of the technique. This review aims to reflect the current status of portable biosensors for common oral pathogens and to lay the foundation for the further realization of portable detection of oral pathogens.

REASSURED diagnostics at point-of-care in sub-Saharan Africa: A scoping review

Point-of-care (POC) diagnostics that meet the REASSURED criteria are essential in combating the rapid increase and severity of global health emergencies caused by infectious diseases. However, little is known about whether the REASSURED criteria are implemented in regions known to have a high burden of infectious diseases such as sub-Saharan Africa (SSA). This scoping review maps evidence of the use of REASSURED POC diagnostic tests in SSA. The scoping review was guided by the advanced methodological framework of Arksey and O'Malley, and Levac et al. We searched the following electronic databases for relevant literature: Scopus, Dimensions, ProQuest Central, Google Scholar, and EBSCOhost (MEDLINE, CINAHL, as well as AFRICA-WIDE). Two reviewers independently screened abstracts and full-text articles using the inclusion criteria as reference. We appraised the quality of the included studies using the mixed-method appraisal tool (MMAT) version 2018. We retrieved 138 publications, comprising 134 articles and four grey literature articles. Of these, only five articles were included following abstract and full-text screening. The five included studies were all conducted in SSA. The following themes emerged from the eligible articles: quality assurance on accuracy of REASSURED POC diagnostic tests, sustainability of REASSURED POC diagnostic tests, and local infrastructure capability for delivering REASSURED POC diagnostic tests to end users. All five articles had MMAT scores between 90% and 100%. In conclusion, our scoping review revealed limited published research on REASSURED diagnostics at POC in SSA. We recommend primary studies aimed at investigating the implementation of REASSURED POC diagnostic tests in SSA.

Ultrafast PCR Detection of COVID-19 by Using a Microfluidic Chip-Based System

With the evolution of the pandemic caused by the Coronavirus disease of 2019 (COVID-19), reverse transcriptase-polymerase chain reactions (RT-PCR) have invariably been a golden standard in clinical diagnosis. Nevertheless, the traditional polymerase chain reaction (PCR) is not feasible for field application due to its drawbacks, such as time-consuming and laboratory-based dependence. To overcome these challenges, a microchip-based ultrafast PCR system called SWM-02 was proposed to make PCR assay in a rapid, portable, and low-cost strategy. This novel platform can perform 6-sample detection per run using multiple fluorescent channels and complete an ultrafast COVID-19 RT-PCR test within 40 min. Here, we evaluated the performance of the microdevice using the gradient-diluted COVID-19 reference samples and commercial PCR kit and determined its limit-of-detection (LoD) as 500 copies/mL, whose variation coefficients for the nucleocapsid (N) gene and open reading frame 1 ab region (ORF1ab) gene are 1.427% and 0.7872%, respectively. The system also revealed an excellent linear correlation between cycle threshold (Ct) values and dilution factors (R2 > 0.99). Additionally, we successfully detected the target RNAs and internal gene in the clinical samples by fast PCR, which shows strong consistency with conventional PCR protocol. Hence, with compact dimension, user-friendly design, and fast processing time, SWM-02 has the capability of offering timely and sensitive on-site molecular diagnosis for prevention and control of pathogen transmission.

Recent Progress in Spectroscopic Methods for the Detection of Foodborne Pathogenic Bacteria

Detection of foodborne pathogens at an early stage is very important to control food quality and improve medical response. Rapid detection of foodborne pathogens with high sensitivity and specificity is becoming an urgent requirement in health safety, medical diagnostics, environmental safety, and controlling food quality. Despite the existing bacterial detection methods being reliable and widely used, these methods are time-consuming, expensive, and cumbersome. Therefore, researchers are trying to find new methods by integrating spectroscopy techniques with artificial intelligence and advanced materials. Within this progress report, advances in the detection of foodborne pathogens using spectroscopy techniques are discussed. This paper presents an overview of the progress and application of spectroscopy techniques for the detection of foodborne pathogens, particularly new trends in the past few years, including surface-enhanced Raman spectroscopy, surface plasmon resonance, fluorescence spectroscopy, multiangle laser light scattering, and imaging analysis. In addition, the applications of artificial intelligence, microfluidics, smartphone-based techniques, and advanced materials related to spectroscopy for the detection of bacterial pathogens are discussed. Finally, we conclude and discuss possible research prospects in aspects of spectroscopy techniques for the identification and classification of pathogens.

Photoluminescent inorganic nanoprobe-based pathogen detection

Pathogens are serious threats to human health, and traditional detection techniques suffer from various limitations. The unique optical properties of photoluminescent inorganic nanomaterials, such as high photoluminescence quantum yields, good photostability, and tunable spectrum, make them ideal tools for the detection of pathogens with high specificity and sensitivity. In this review, the design strategies, working mechanisms, and applications of photoluminescent inorganic nanomaterial-based probes in pathogen detection are introduced. In particular, the design and construction of stimuli-responsive nanoprobes and their potential in these fields are highlighted.

Single bacteria detection by droplet DNAzyme-coupled rolling circle amplification

We described a new system termed droplet DNAzyme-coupled rolling circle amplification (dDRCA) that can selectively detect bacteria from clinical urine samples with single-cell sensitivity within 1.5 h compared with the several hours needed for traditionally used culture-based methods.

Toward Next-Generation Mobile Diagnostics: Near-Field Communication-Powered Electrochemiluminescent Detection

Mobile phones have been used in combination with point of care (PoC) devices for over a decade now. However, their use seems restricted to the detection of sensing events using the video and camera functions. In contrast, the complementary ability to use mobile phones to power such PoC devices has been largely unexplored. This work demonstrates the proof-of-principle that a smartphone can be used to both power and analyze an electrochemiluminescence (ECL) detection system. A printed device is presented featuring an electrochemical cell connected in series to a rectenna that is able to use the Near Field Communication (NFC, 13.56 MHz) signal to provide the energy needed to generate ECL from Ru(bpy)₃²⁺/tri-n-propylamine. The emitted light, the intensity of which is directly proportional to the concentration of the ruthenium complex, can then be captured by the mobile phone camera and analyzed. This work presents the fabrication and the electrical and electrochemical characterization of the device. Effective voltages ranging from 0.90 to 4.50 V have been recorded, depending on the coupling between emitter and receiver, which translate into working electrode potentials ranging from 0.76 up to 1.79 V vs Ag. Detection and quantification limits of 0.64 and 1.52 μM, respectively, have been achieved for Ru(bpy)₃²⁺, and linear ranges up to 0.1 mM (red channel) and no less than 1.0 mM (green channel) have been found.