Point-of-care Testing Devices Research Articles

Improvement of point of care testing device for accurate whole blood glucose measurement in early neonates.

It is important that blood glucose concentrations be accurately and conveniently measured in infants. However, especially in the early neonatal period, point-of-care testing devices used for adults may not accurately measure blood glucose concentrations in neonates. In Study 1, the accuracy of neonatal whole-blood glucose measurements was evaluated for the existing glucose analyser Glutest Mint® (hereinafter MINT1; Sanwa Kagaku Kenkyusho, Nagoya, Japan) by comparing the data with reference blood glucose concentrations. In Study 2, we used MINT2, which was modified based on the findings from Study 1, to measure whole-blood glucose concentrations in newborns, and the accuracy of the measurements was compared with that of MINT1. Blood glucose concentrations were measured in 100 infants each in Study 1 and 2. In Study 1, the whole-blood glucose concentrations measured using MINT1 were found to be significantly lower than the reference blood glucose concentrations in early neonates. The results of Study 1 suggested that characteristics of erythrocyte membranes in early neonates affected the measurements. Therefore, we conducted Study 2 using MINT2, which was modified to be less susceptible. MINT2 was found to accurately measure whole-blood glucose concentrations in the early neonatal period. The study showed that the point-of-care testing device could be improved to allow for accurate whole-blood glucose measurements in the early neonatal period.

The Classification of VOCs Based on Sensor Images Using a Lightweight Neural Network for Lung Cancer Diagnosis

The application of artificial intelligence to point-of-care testing (POCT) disease detection has become a hot research field, in which breath detection, which detects the patient’s exhaled VOCs, combined with sensor arrays of convolutional neural network (CNN) algorithms as a new lung cancer detection is attracting more researchers’ attention. However, the low accuracy, high-complexity computation and large number of parameters make the CNN algorithms difficult to transplant to the embedded system of POCT devices. A lightweight neural network (LTNet) in this work is proposed to deal with this problem, and meanwhile, achieve high-precision classification of acetone and ethanol gases, which are respiratory markers for lung cancer patients. Compared to currently popular lightweight CNN models, such as EfficientNet, LTNet has fewer parameters (32 K) and its training weight size is only 0.155 MB. LTNet achieved an overall classification accuracy of 99.06% and 99.14% in the own mixed gas dataset and the University of California (UCI) dataset, which are both higher than the scores of the six existing models, and it also offers the shortest training (844.38 s and 584.67 s) and inference times (23 s and 14 s) in the same validation sets. Compared to the existing CNN models, LTNet is more suitable for resource-limited POCT devices.

Integrated Sandwich-Paper 3D Cell Sensing Device to In Situ Wirelessly Monitor H2O2 Released from Living Cells.

Point-of-care testing (POCT) has attracted great interest because of its prominent advantages of rapidness, precision, portability, and real-time monitoring, thus becoming a powerful biomedical device in early clinical diagnosis and convenient medical treatments. However, its complicated manufacturing process and high expense severely impede mass production and broad applications. Herein, an innovative but inexpensive integrated sandwich-paper three-dimensional (3D) cell sensing device is fabricated to in situ wirelessly detect H2O2 released from living cells. The paper-based electrochemical sensing device was constructed by a sealed sandwiched bottom plastic film/fiber paper/top hole-centered plastic film that was printed with patterned electrodes. A new (Fe, Mn)3(PO4)2/N-doped carbon nanorod was developed and immobilized on the sensing carbon electrode while cell culture solution filled the exposed fiber paper, allowing living cells to grow on the fiber paper surrounding the electrode. Due to the significantly shortening diffusion distance to access the sensing sites by such a unique device and a rationally tuned ratio of Fe2+/Mn2+, the device exhibits a fast response time (0.2 s), a low detection limit (0.4 μM), and a wide detection range (2-3200 μM). This work offers great promise for a low-cost and highly sensitive POCT device for practical clinic diagnosis and broad POCT biomedical applications.

Paper-based uric acid assay in whole blood samples by Zn2+ protein precipitation and enzyme-free colorimetric detection.

Uric acid (UA) is an important biomarker, as a high concentration in blood can lead to gout and further renal syndrome. Although several point-of-caretesting (POCT) devices have been reported to detect UA, there are some limitations such as the requirement for uricase and the complicated pretreatment of serum/plasma samples, which restricts their use at home or in undeveloped areas. In this work, we developed an approach by applying Zn2+ to precipitate proteins and cells in whole blood to avoid interference with the chromogenic reaction. We used carboxymethylcellulose (CMC) to immobilize tetramethylbenzidine (TMB) on a nitrocellulose membrane for colorimetric detection. Using the oxidization properties of H2O2, which turns TMB into oxidized tetramethylbenzidine (TMBox) in the presence of catalyst gold nanoparticles (AuNPs), we successfully constructed an enzyme-free paper-based POCT device using the reduction reaction of UA and TMBox for simple, speedy, and cheap colorimetric detection of UA, achieving a detection time of 8min, a linear range of 0-150μg/mL, and an LOD of 25.79μg/mL. The UA concentration in whole blood samples was further measured and correlated well with the clinical value (R2 = 0.8212). Thus, the proposed assay has the potential for POCT diagnosis, monitoring, and prognosis of diseases related to UA.

Validation of the blood glucose testing method on the Accu-chek Inform II

Blood glucose testing, including capillary blood glucose, is the recommended test for the diagnosis and monitoring of diabetes treatment. Currently, capillary blood glucose testing is performed on point-of-care testing (POCT) with reasonable cost, fast time, convenience, supporting timely diagnosis and treatment. However, in order to select POCT devices that meet quality standards, it is necessary to strictly control the laboratory. Object and method: Confirmation of the capillary blood sugar testing method on the Accu-chek Inform II (Acc-II) machine including the following indicators: accuracy, precision, linear range, comparison of test results according to the recommendations of the Clinical & Laboratory Standards Institute (CLSI) (EP15A3, EP06A, EP09A3). The authors compared results on the testing machine in the central laboratory (Cobas 8000) of blood glucose testing on the POCT machine with the results of whole capillary blood, whole venous blood, and plasma venous samples. Results: Precision, accuracy, and linearity were confirmed as published. The linear range of the method is from 1.6 to 31 mmol/l. The difference between capillary blood glucose pairs and plasma venous glucose, whole blood venous glucose on Accu-chek Inform II and plasma venous blood glucose on Cobas 8000 machine are 6.89, -8.62, and -10.97%, respectively.

A smartphone-based electrochemical POCT for CEA based on signal amplification of Zr6MOFs.

Carcinoembryonic antigen (CEA) is a biomarker of high expression in cancer cells. Highly sensitive and selective detection of CEA holds significant clinical value in the diagnosis, monitoring and efficacy evaluation of malignant tumors. In this work, a smartphone-based electrochemical point-of-care testing (POCT) platform for the detection of CEA was developed based on a Zr6MOF signal amplification strategy. Ferrocene labeled DNA strands (Fc-DNA) were immobilized on Zr6MOFs to form a Fc-DNA/Zr6MOF signal probe. Double-stranded DNA (dsDNA) formed by complementary DNA (cDNA) and CEA aptamer was assembled on a screen-printed electrode via an Au-S bond. When CEA was added, the aptamer specifically bound with CEA, resulting in the exposure of cDNA. Then, Fc-DNA/Zr6MOF signal probes were introduced on the electrode surface through hybridization between Fc-DNA and cDNA. The detection of CEA was realized by measuring the electrochemical response of Fc. The POCT device was made by connecting a modified electrode with a smartphone through a Sensit Smart USB flash disk. Due to the signal amplification of Zr6MOFs, this POCT platform exhibited high sensitivity, wide linear range, and low detection limit for CEA detection. The developed POCT platform has been used for the detection of CEA in actual human serum samples with satisfactory results.

Diagnostic performance of a point-of-care test device for periodontitis using human saliva: a single-center, single-blinded, confirmatory study.

Recently, matrix metalloproteinase-8 (MMP-8) has been used to diagnose periodontal disease in a point-of-care (POC) test in order to save time and cost relative to the traditional diagnostic workflow. This study aimed to investigate the diagnostic performance of INCLIX TRF MMP-8, a POC testing device for periodontitis using the area under the receiver operating characteristic curve, sensitivity, specificity, and predictive values. Full-mouth periodontal examination and radiographic analysis were used for evaluating periodontal condition based on the 2018 classification of periodontal disease. A dichotomous diagnosis of clinical periodontal condition was performed using the POC device. The relationships among periodontal condition and the concentration of MMP-8, tooth loss (TL), gingival index (GI), plaque index (PI), and alveolar bone loss (ABL) were assessed by the Spearman rank correlations (rs). In all, 108 cases of non-periodontitis (NP) and 191 cases of periodontitis (P), including 38 cases of periodontitis stage I, 42 cases of periodontitis stage II, 99 cases of periodontitis stage III, and 11 cases of periodontitis stage IV, were enrolled in this study. Diagnostic accuracy in assessing periodontal condition with the POC device improved when it was used with participants aged ≥ 40 years. There were weak positive correlations between periodontal condition and MMP-8 and between periodontal condition and GI (rs2 = 0.1124 and rs2 = 0.0906, respectively), whereas a strong positive correlation between periodontal condition and alveolar bone loss (rs2 = 0.6877) was observed. The POC device investigated in this study is a potential tool to distinguish between NP and P in individuals ≥ 40 years of age.

Point of care testing in Croatia: a survey of the Working group for point of care testing of the Croatian society of medical biochemistry and laboratory medicine.

The aim of this study was to investigate attitudes and routine procedures in point of care testing (POCT) among non-laboratory and laboratory healthcare professionals in Croatia. The Working Group (WG) for POCT of the Croatian society of medical biochemistry and laboratory medicine has designed two anonymous surveys for laboratory staff and non-laboratory staff with a total of 44 questions/statements on POCT (27 questions for non-laboratory staff and 17 for laboratory staff). Surveys were sent to 184 medical biochemistry laboratory (MBL) managers, the Croatian medical chamber and the Croatian chamber of nurses. The survey was disseminated using the online survey platform SurveyMonkey. A total of 112 non-laboratory healthcare professionals and 50 laboratories participated in the survey, which represents a response rate of 0.25% for non-laboratory professionals and 27% for MBLs. The majority of non-laboratory staff stated that POCT enables better medical care for the patient (90/112) and that the implementation of new POCT devices should be the responsibility of a POCT team comprising laboratory and clinical healthcare professionals. The great majority of responding MBLs (42/50) acknowledge that POCT is necessary for better patient care, and also realize that validation of POCT devices and comparison to the central laboratory is necessary before implementation (49/50). The majority of participants consider POCT as a medical tool that enables better patient care but there is still a lack of communication between laboratory and clinical staff. The study identified some critical spots that will help to create national guidelines to ensure high patient safety when using POCT devices.

An Alternating Current Electroosmotic Flow-Based Ultrasensitive Electrochemiluminescence Microfluidic System for Ultrafast Monitoring, Detection of Proteins/miRNAsin Unprocessed Samples.

Early diagnosis of acute diseases is restricted by the sensitivity and complex process of sample treatment. Here, an ultrasensitive, rapid, and portable electrochemiluminescence-microfluidic (ECL-M) system is described via sandwich-type immunoassay and surface plasmonic resonance (SPR) assay. Using a sandwich immunoreaction approach, the ECL-M system employs cardiac troponin-I antigen (cTnI) as a detection model with a Ru@SiO2 NPs labeled antibody as the signal probe. For miR-499-5p detection, gold nanoparticles generate SPR effects to enhance Ru(bpy)3 2+ ECL signals. The system based on alternating current (AC) electroosmotic flow achieves an LOD of 2 fg mL-1 for cTnI in 5 min and 10 aM for miRNAs in 10 min at room temperature. The point-of-care testing (POCT) device demonstrated 100% sensitivity and 98% specificity for cTnI detection in 123 clinical serum samples. For miR-499-5p, it exhibited 100% sensitivity and 97% specificity in 55 clinical serum samples. Continuous monitoring of these biomarkers in rats' saliva, urine, and interstitial fluid samples for 48 hours revealed observations rarely documented in biotic fluids. The ECL-M POCT device stands as a top-performing system for ECL analysis, offering immense potential for ultrasensitive, rapid, highly accurate, and facile detection and monitoring of acute diseases in POC settings.

Mobile Point-of-Care Device Using Molecularly Imprinted Polymer-Based Chemosensors Targeting Interleukin-1β Biomarker.

Molecularly imprinted polymers (MIPs) have garnered significant attention as a promising material for engineering specific biological receptors with superior chemical complementarity to target molecules. In this study, we present an electrochemical biosensing platform incorporating MIP films for the selective detection of the interleukin-1β (IL-1β) biomarker, particularly suitable for mobile point-of-care testing (POCT) applications. The IL-1β-imprinted biosensors were composed of poly(eriochrome black T (EBT)), including an interlayer of poly(3,4-ethylene dioxythiophene) and a 4-aminothiophenol monolayer, which were electrochemically polymerized simultaneously with template proteins (i.e., IL-1β) on custom flexible screen-printed carbon electrodes (SPCEs). The architecture of the MIP films was designed to enhance the sensor sensitivity and signal stability. This approach involved a straightforward sequential-electropolymerization process and extraction for leaving behind cavities (i.e., rebinding sites), resulting in the efficient production of MIP-based biosensors capable of molecular recognition for selective IL-1β detection. The electrochemical behaviors were comprehensively investigated using cyclic voltammograms and electrochemical impedance spectroscopy responses to assess the imprinting effect on the MIP films formed on the SPCEs. In line with the current trend in in vitro diagnostic medical devices, our simple and effective MIP-based analytical system integrated with mobile POCT devices offers a promising route to the rapid detection of biomarkers, with particular potential for periodontitis screening.

Ambulatory human chorionic gonadotrophin (hCG) testing: a verification of two hCG point of care devices.

Quantitative human chorionic gonadotropin (hCG) measurements are used to manage women classified with a pregnancy of unknown location (PUL). Two point of care testing (POCT) devices that quantify hCG are commercially available. We verified the i-STAT 1 (Abbott) and the AQT 90 FLEX (Radiometer) prior to use in PUL triage. Tests for precision, external quality assurance (EQA), correlation, hook effect and recovery were undertaken alongside a POCT usability assessment during this prospective multi-center verification. Coefficients of variation ranged between 4.0 and 5.1 % for the three i-STAT 1 internal quality control (IQC) solutions and between 6.8 and 7.3 % for the two AQT IQC solutions. Symmetric differences in POCT EQA results when compared with laboratory and EQA stock values ranged between 3.2 and 24.5 % for the i-STAT 1 and between 3.3 and 36.9 % for the AQT. Correlation coefficients (i-STAT 1: 0.96, AQT: 0.99) and goodness of fit curves (i-STAT 1: 0.92, AQT: 0.99) were excellent when using suitable whole blood samples. An hCG hook effect was noted with the i-STAT 1 between 572,194 and 799,089 IU/L, lower than the hook effect noted with the AQT, which was between 799,089 and 1,619,309 IU/L. When hematocrit concentration was considered in sample types validated for use with each device, hCG recovery was 108 % with the i-STAT 1 and 98 % with the AQT. The i-STAT 1 scored lower on usability overall (90/130) than the AQT (121/130, p<0.001, Mann-Whitney). Both hCG POCT devices were verified for use in clinical practice. Practical factors must also be considered when choosing which device to use in each unit.

A point-of-care solid-phase colorimetric sensor based on the enzyme-induced metallization for ALP detection

Alkaline phosphatase (ALP) is a crucial biomarker for clinical diagnosis, which is closely related to the physiological homeostasis regulation process of human body. And the abnormal level of ALP is associated with numerous diseases, such as liver dysfunction, bone diseases, diabetes, and so on. In order to meet the demand of personalized healthcare, it is particularly important to develop a miniaturized point-of-care testing (POCT) device for ALP detection. Herein, a portable solid-phase colorimetric sensor based on enzyme-induced metallization signal amplification strategy was constructed for ALP detection. The AuNPs modified on the glass slides acted as crystal seeds, allowing Ag+ in the solution to be reduced and deposited on the surface of AuNPs, which further formed the gold core and silver shell (Au@Ag) complex and generated visual signals. The visual signals were recorded by a smartphone and quantified using open-source ImageJ software. Under the optimal conditions, the proposed method exhibited a good linear relationship from 2.0 to 16.0 pM, and the detection limit was as low as 0.9 pM. In addition, it was further successfully applied for ALP detection in non-transparent and complex samples (milk, different types of cells). A sensitive, low cost, rapid and convenient solid-phase sensor was developed for ALP detection, which was expected to provide a promising strategy for POCT devices.

Smartphone-based polydiacetylene colorimetric sensor for point-of-care diagnosis of bacterial infections

The rapid progress in point-of-care testing (POCT) has become a promising decentralized patient-centered approach for the control of infectious diseases, especially in resource-limited settings. POCT devices should be inexpensive, rapid, simple operation and preferably require no power supply. Here, we developed a simple bacterial sensing platform that can be operated by a smartphone for bacteria identification and antimicrobial susceptibility testing (AST) based on using a polydiacetylene (PDA) arrayed membrane chip. Each PDA array produced a unique color ‘fingerprint’ pattern for each bacteria based on different modes of action of toxins from bacteria on biomimetic lipid bilayers within PDA-lipid assemblies. We show that the PDA-based device can detect viable cells of bacteria as low as 104 ​CFU/mL within 1.5 ​h compared with several days of conventional bacterial identification, with the aid of a smartphone app. The device can also be used for an antimicrobial susceptibility test (AST) for at least two broad-spectrum antimicrobials within 4 ​h and provide identification of antimicrobial susceptibility and resistance, enabling the selection of appropriate therapies. This PDA-based sensing platform provides an alternative way for bacterial detection and could be used as a portable and inexpensive POCT device for the rapid detection of bacterial infection in limited-resource settings.

A-374 Analytical Performance Assessment and Comparison of Point of Care Testing (POCT) Devices for Blood Lipids Measurements

Abstract Background Cardiovascular diseases (CVDs) are the leading cause of death in the U.S. and worldwide. According to the World Health Organization (WHO), worldwide, 85% of CVD deaths are due to heart disease and strokes, and over 75% occur in low- and middle-income countries (LMICs). Early detection and treatment are key to preventing the consequences of CVD. Point-of-care testing (POCT) devices offer alternatives to screening large populations for CVD risk. Although POCT are increasingly used for screening, only few information is available about their accuracy and reliability. Methods Eight POCT devices for blood lipids that previously successfully participated in the CDC CVD Biomarker Standardization Programs were used in this preliminary study. The analytical performance for all eight devices was assessed using split sample comparisons to the CDC reference measurement procedures for measurements performed in whole blood (WB) and serum. Specifically, the accuracy of total cholesterol (TC) was determined in WB and serum. The accuracy of high-density lipoprotein-cholesterol (HDL-c), and low-density lipoprotein-cholesterol (LDL-c) was determined in serum. The precision of TC, HDL-c, LDL-c, and triglycerides (TG) was determined in WB and serum. Results The reference values of the specimens from 20 donors ranged between 154–279 mg/dL, 36.9–109 mg/dL, and 71.1–182 mg/dL for TC, HDL-c, and LDL-c in serum, and between 145–210 mg/dL for TC in WB. Preliminary assessments found that the mean bias for each instrument ranged from -7.86%–13.82% and from -11.90%–3.24% for TC in WB and serum, respectively. For serum HDL-c samples, the mean bias ranged from −6.81%–15.43%. The mean bias for serum LDL-c samples ranged from −22.40% to 3.08%. For three devices, approximately 30% of the WB measurements and approximately 50% of the serum measurements were reported as outside of the measurement range. The mean imprecision for each instrument ranged from 2.2%–13.75% and from 1.88%–11.76% for TC in WB and serum, respectively. For HDL-c, the mean imprecision ranged from 5.36%–23.21% and from 2.30% to 26.69% in WB and serum, respectively. The mean imprecision ranged from 4.82%–20.34% and from 3.06%–20.54% for LDL-c in WB and serum, respectively. For TG, the mean imprecision ranged from 5.78%–23.91% and from 1.71%–11.02% in WB and serum, respectively. Conclusion These preliminary findings about the analytical performance of POCT devices indicate notable differences in accuracy and precision for lipids measured in WB and serum, with serum measurements being more likely within performance requirements than WB measurements. Some devices appear to be more likely to report values outside the measurement range even though reference values are within the measurement range of the device. Further studies to verify these preliminary findings with more individual donor samples are underway.

A-371 Comparative Evaluation of POCT Based Lysophosphatidylcholine Measurement

Abstract Background Lysophosphatidylcholine (LPC), also referred to as lysolecithin, is a phospholipid intermediate whose concentrations have been correlated with such diseases as cancer, artherosclerosis and diabetes. Recently, serum LPC concentrations have been reported to be candidate biomarker for bacterial infection and sepsis. In this study, we evaluated the comparative performance of the point-of-care test (POCT) measurement of LPC using CareBuddy Multi Analyzer. Methods A total of 120 serum samples were analyzed for LPC by enzymatic spectrophotometry (CareBuddy Multi analyzer, CareBuddy catridge) and mass spectrometry based method (TSQ Altis LC/MS/MS) as the reference method. Additionally, subset of samples with enough remnant volumes were assessed for PCT and CRP using electrochemiluminescence immunoassay (Roche Cobas e801, Roche Elecsys BRAHMS PCT) and immunoturbidimetric assay (Roche Cobas c702, Sekisui Nanopia CRP), respectively. The equivalence and correlation among the methods were evaluated using linear regression analysis. Results The LPC measurement by POCT analyzer showed high correlations with the LC-MS based reference method (y = 1.02x + 1.26). The LPC measurement by POCT showed correlation coefficient for PCT (Pearson's r = −0.316) and CRP (Pearson's r = −0.618). Upon applying clinical cutoffs for qualitative result, LPC POCT measurement showed good agreements to each reference methods. Conclusion In summary, our results suggest that the quantitative measurement for LPC via POCT device in human serum samples possess possible clinical feasibility as a novel sepsis biomarker.

Point-of-Care Testing for the Detection of MicroRNAs: Towards Liquid Biopsy on a Chip.

Point-of-care (PoC) testing is revolutionizing the healthcare sector improving patient care in daily hospital practice and allowing reaching even remote geographical areas. In the frame of cancer management, the design and validation of PoC enabling the non-invasive, rapid detection of cancer markers is urgently required to implement liquid biopsy in clinical practice. Therefore, focusing on stable blood-based markers with high-specificity, such as microRNAs, is of crucial importance. In this work, we highlight the potential impact of circulating microRNAs detection on cancer management and the crucial role of PoC testing devices, especially for low-income countries. A detailed discussion about the challenges that should be faced to promote the technological transfer and clinical use of these tools has been added, to provide the readers with a complete overview of potentialities and current limitations.

Establishing a community pharmacist‐led vitamin D point‐of‐care testing service

AbstractIntroductionGrowing recognition of the role of vitamin D augmented the demand for a point‐of‐care testing (POCT) framework, unveiling a niche for development of a novel service.ObjectivesReview available vitamin D POCT devices and validate vitamin D POCT; Develop and validate framework for vitamin D POCT; Conduct pilot study for pharmacist‐led vitamin D POCT framework in community pharmacy.MethodsVitamin D POCT devices were appraised by considering specifications and the identified vitamin D POCT kit was validated by comparing results with gold standard method in 20 participants, employing Cohen's Kappa coefficient. A framework consisting of a Data Collection Sheet, a standard operating procedure and Action Plan record for pharmacist‐led vitamin D POCT was developed and validated. The framework was piloted in a community pharmacy with 80 participants and patient data was correlated with POCT result. Data was analyzed using the chi‐square test.ResultsThe appraisal identified a semi‐quantitative POCT which conforms with European Union (EU) regulations. Concordance between POCT and gold standard was observed (κ = 0.84, p &lt; 0.001). Of the 80 participants, 49 had insufficient; 8 had deficient vitamin D levels. The framework developed was practical to be applied in the community pharmacy setting. Participants suffering from chronic conditions are more likely to have their vitamin D levels tested (p = 0.042), those suffering from metabolic disorders being more likely to have deficient/insufficient vitamin D levels (p = 0.026).ConclusionThe study identified a POCT device for use within a framework for community pharmacist‐led assessment of vitamin D in the context of collaborative care. A high incidence of vitamin D insufficiency was observed, indicating the value of providing access to this service at primary care level. An accessible vitamin D testing service to participants, supported by community pharmacist professional advice, facilitates early detection of vitamin D insufficiency and management.

Manipulating Physicochemical Properties of Biosensor Platform with Polysuccinimide-Silica Nanocomposite for Enhanced Protein Detection.

As point-of-care testing (POCT) is becoming the new paradigm of medical diagnostics, there is a growing need to develop reliable POCT devices that can be conveniently operated in a minimally invasive manner. However, the clinical potential of POCT diagnostics is yet to be realized, mainly due to the limited and inconsistent amount of collected samples on these devices, undermining their accuracy. This study proposes a new biosensing platform modified with a functional polysuccinimide (PSI)-silica nanoparticle (SNP) composite system that can substantially increase the protein conjugation efficiency by modulating physicochemical interaction with proteins by several hundred percent from an unmodified device. The efficacy of this PSI-SNP system is further validated by applying it on the surface of a microneedle array (MN), which has emerged as a promising POCT device capable of accessing interstitial fluid through minimal penetration of the skin. This PSI-SNP MN is demonstrated to detect a wide array of proteins with high sensitivity on par with conventional whole serum analysis, validated by in vivo animal testing, effectively displaying broad applicability in biomedical engineering.

Efficient Nanozyme-Triggered Pressure Sensor for Point-of-Care Immunoassay: Visual Sensing and Time Readout Device.

Point-of-care testing (POCT), with its portability and high sensitivity, is an analytical device for rapid on-site sensing and detection. In this study, a POCT device was designed for the portable detection of illegal additives by integrating a coil device that can visually sense color distance and a two-electrode electrochemical system. Real-time monitoring of pressure changes was achieved by driving CeO2@Pt/Au nanoparticle (NP)-labeled antibodies into a competitive immunoreaction, in which CeO2 and Pt/Au synergistically catalyzed the production of large amounts of O2 from H2O2, leading to a significant increase in gas within the closed chamber. Attractively, the coil device converted the pressure stimulus into visually readable change in distance for semi-quantitative detection of the target substance, while the electrical signal output caused by the changes of the solution around the electrodes achieved accurate and reliable quantification of the target. In addition, the proposed dual-mode pressure immunoassay device has acceptable selectivity, stability, and reproducibility. Herein, this portable device, which enables target concentration readings by converting pressure into multiple signals, provides an effective way to visualize POCT assays in resource-limited areas.

Application of Shear Horizontal Surface Acoustic Wave (SH-SAW) Immunosensor in Point-of-Care Diagnosis.

Point-of-care testing (POCT), also known as on-site or near-patient testing, has been exploding in the last 20 years. A favorable POCT device requires minimal sample handling (e.g., finger-prick samples, but plasma for analysis), minimal sample volume (e.g., one drop of blood), and very fast results. Shear horizontal surface acoustic wave (SH-SAW) biosensors have attracted a lot of attention as one of the effective solutions to complete whole blood measurements in less than 3 min, while providing a low-cost and small-sized device. This review provides an overview of the SH-SAW biosensor system that has been successfully commercialized for medical use. Three unique features of the system are a disposable test cartridge with an SH-SAW sensor chip, a mass-produced bio-coating, and a palm-sized reader. This paper first discusses the characteristics and performance of the SH-SAW sensor system. Subsequently, the method of cross-linking biomaterials and the analysis of SH-SAW real-time signals are investigated, and the detection range and detection limit are presented.