Search Results (47)

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common enzymopathy with significant clinical implications, particularly in malaria-endemic regions and in the management of neonatal hyperbilirubinemia. Timely and accurate detection of G6PD deficiency is critical to prevent life-threatening hemolytic events following oxidative drug administration. This study evaluated the MyG6PD device, a quantitative point-of-care (PoC) tool, for the assessment of hemoglobin concentration and G6PD enzyme activity. Analytical performance was benchmarked against laboratory spectrophotometry and the STANDARD G6PD Analyzer™ (SD Biosensor; Suwon-si, Republic of Korea). MyG6PD demonstrated excellent linearity (R² ≥ 0.99), accuracy (bias < ±15%), and precision (CV < 15%) across normal, intermediate, and deficient activity ranges, including heterozygous females with intermediate phenotypes. The device’s compact, battery-operated design, rapid turnaround, and minimal training requirements support its use in decentralized and resource-limited settings. Furthermore, cost-effective consumables and robust detection of intermediate activity highlight its potential for large-scale deployment. Overall, MyG6PD provides a reliable, accessible, and clinically actionable solution for urgent G6PD deficiency screening, enabling safer administration of oxidative therapies and improving patient outcomes in high-risk populations. Full article

Early and accurate detection of plant diseases is critical for ensuring global food security and agricultural resilience. Ratoon stunting disease (RSD), caused by the bacterium Leifsonia xyli subsp. xyli (Lxx), is among the most economically significant diseases of sugarcane worldwide. Its cryptic nature—characterized by an absence of visible symptoms—renders timely diagnosis particularly difficult, contributing to substantial undetected yield losses across major sugar-producing regions. Here, we report the development of a potential-induced electrochemical (EC) nanobiosensor platform for the rapid, low-cost, and field-deployable detection of Lxx DNA directly from crude sugarcane sap. This method eliminates the need for conventional nucleic acid extraction and thermal cycling by integrating the following: (i) a boiling lysis-based DNA release from xylem sap; (ii) sequence-specific magnetic bead-based purification of Lxx DNA using immobilized capture probes; and (iii) label-free electrochemical detection using a potential-driven DNA adsorption sensing platform. The biosensor shows exceptional analytical performance, achieving a detection limit of 10 cells/µL with a broad dynamic range spanning from 10⁵ to 1 copy/µL (r = 0.99) and high reproducibility (SD < 5%, n = 3). Field validation using genetically diverse sugarcane cultivars from an inoculated trial demonstrated a strong correlation between biosensor signals and known disease resistance ratings. Quantitative results from the EC biosensor also showed a robust correlation with qPCR data (r = 0.84, n = 10, p < 0.001), confirming diagnostic accuracy. This first-in-class EC nanobiosensor for RSD represents a major technological advance over existing methods by offering a cost-effective, equipment-free, and scalable solution suitable for on-site deployment by non-specialist users. Beyond sugarcane, the modular nature of this detection platform opens up opportunities for multiplexed detection of plant pathogens, making it a transformative tool for early disease surveillance, precision agriculture, and biosecurity monitoring. This work lays the foundation for the development of a universal point-of-care platform for managing plant and crop diseases, supporting sustainable agriculture and global food resilience in the face of climate and pathogen threats. Full article

Interferon-gamma release assays (IGRAs) have gained attention for the diagnosis of latent tuberculosis infection (LTBI) due to their higher specificity compared to the tuberculin skin test (TST). However, the IGRA’s performance varies across different populations. This study evaluated the diagnostic performance of three IGRAs (TBF-FIA, TBF-ELISA, and QFT-Plus) in Ghana, comparing them among individuals exposed and unexposed to MTB infection. Conducted in TB clinics across three regions, this prospective and cross-sectional study included healthy individuals with no known TB exposure (unexposed group) and patients with confirmed active TB (exposed group). Blood samples were tested using all three assays as per the manufacturers’ guidelines. The TBF-ELISA showed 3.4% higher sensitivity but 4.6% lower specificity compared to QFT-Plus. The TBF-FIA had sensitivity of 78.5–87.3% and specificity of 82.9–90.0%. These findings indicate that while the three IGRAs offer similar diagnostic accuracy, the variations in specificity and limited data on assays like TBF-FIA require further investigation. Full article

Clostridioides difficile infection (CDI) has evolved to be the most significant cause of healthcare-associated diarrhoea and one of the leading representatives of healthcare-associated infections, with a high associated mortality. The aim of this retrospective study was to record the incidence rates and the epidemiological and clinical features of CDI in a large tertiary hospital of northern Greece in the years 2022-2023. All patients with CDI-compatible symptomatology and a positive CDI diagnostic test (GDH—glutamate dehydrogenase and toxin-positive FIA—Fluorescent Immuno-chromatography—SD Biosensor, and/or film array) were included (104 from a total of 4560 admitted patients). Their demographic, laboratory, and clinical data were recorded and analysed. The incidence of CDI in admitted patients was found to be higher than previous reports in the geographical area, reaching 54.6/10,000 patient days and following a rising trend over the course of the study. Thirty-day mortality was high (39.4%), potentially related to new emerging hypervirulent C. difficile strains. In view of the high prevalence of multidrug-resistant organisms in the region, and the significant mortality associated with this infection, these findings particularly point to the need for the implementation of organized surveillance and infection prevention protocols. Full article

This study presents and compares two methods for identifying the types of extracellular vesicles (EVs) from different cell lines. Through SDS-PAGE analysis, we discovered that the ratio of CD63 to CD81 in different EVs is consistent and distinct, making it a reliable characteristic for recognizing EVs secreted by cancer cells. However, the electrophoresis and imaging processes may introduce errors in the concentration values, especially at lower concentrations, rendering this method potentially less effective. An alternative approach involves the use of quartz crystal microbalance (QCM) and electroanalytical interdigitated electrode (IDT) biosensors for EV type identification and quantification. The QCM frequency shift caused by EVs is directly proportional to their concentration, while electroanalysis relies on measuring the curvature of the I−V curve as a distinguishing feature, which is also proportional to EV concentration. Linear regression lines for the QCM frequency shift and the electroanalysis curvature of various EV types are plotted separately, enabling the estimation of the corresponding concentration for an unknown EV type on the graphs. By intersecting the results from both biosensors, the unknown EV type can be identified. The biosensor analysis method proves to be an effective means of analyzing both the type and concentration of EVs from different cell lines. Full article

In 2022–23, the human monkeypox virus (MPXV) caused a global outbreak in several non-endemic countries. Here, we evaluated the diagnostic performance of four real-time qualitative PCR assays for the laboratory diagnosis of mpox (monkeypox) monkeypox disease. From July to August 2022, 27 positive and 10 negative specimens (lesion, crust and exudate swabs) were tested in the laboratory of the Hygiene Unit of the San Martino Hospital (Genoa, Italy) by using home-made real-time PCR to detect MPXV generic G2R_G DNA. According to the manufacturer’s instructions, we also retrospectively analyzed these specimens using RealCycler MONK-UX/-GX (Progenie Molecular), STANDARD M10 MPX/OPX (SD Biosensor), Novaplex MPXV (Seegene Inc.) and RealStar Orthopoxvirus PCR Kit 1.0 (Altona Diagnostics) assays, recognized as research-use-only tests. The diagnostic accuracy and sensitivity of these assays ranged from 97.3% (95% CI: 86.2–99.5%) to 100% (95% CI: 90.6–100%) and 96.3% (95% CI: 81.72–99.34%) to 100% (95% CI: 72.2–100%), respectively. The RealCycler MONK-UX and STANDARD M10 MPX/OPX did not detect one positive sample with a cycle threshold of 36. The overall specificity was 100% (95% CI: 72.2–100%), and Cohen’s Kappa values ranged from 1 (95% CI: 0.67–1) to 0.93 (95% CI: 0.61–1). As they are highly accurate, reliable and user-friendly, these tests should be recommended for the routine or rapid laboratory discrimination of mpox from other rash illnesses. Full article

Atherosclerosis is an inflammatory disease of the arteries associated with alterations in lipid and other metabolism and is a major cause of cardiovascular disease (CVD). LDL consists of several subclasses with different sizes, densities, and physicochemical compositions. Small dense LDL (sd-LDL) is a subclass of LDL. There is growing evidence that sd-LDL-C is associated with CVD risk, metabolic dysregulation, and several pathophysiological processes. In this study, we present a straightforward membrane device filtration method that can be performed with simple laboratory methods to directly determine sd-LDL in serum without the need for specialized equipment. The method consists of three steps: first, the precipitation of lipoproteins with magnesium harpin; second, the collection of effluent from a 100 nm filter; and third, the quantification of sd-LDL-ApoB in the effluent with an SH-SAW biosensor. There was a good correlation between ApoB values obtained using the centrifugation (y = 1.0411x + 12.96, r = 0.82, n = 20) and filtration (y = 1.0633x + 15.13, r = 0.88, n = 20) methods and commercially available sd-LDL-C assay values. In addition to the filtrate method, there was also a close correlation between sd-LDL-C and ELISA assay values (y = 1.0483x − 4489, r = 0.88, n = 20). The filtration treatment method also showed a high correlation with LDL subfractions and NMR spectra ApoB measurements (y = 2.4846x + 4.637, r = 0.89, n = 20). The presence of sd-LDL-ApoB in the effluent was also confirmed by ELISA assay. These results suggest that this filtration method is a simple and promising pretreatment for use with the SH-SAW biosensor as a rapid in vitro diagnostic (IVD) method for predicting sd-LDL concentrations. Overall, we propose a very sensitive and specific SH-SAW biosensor with the ApoB antibody in its sensitive region to monitor sd-LDL levels by employing a simple delay-time phase shifted SH-SAW device. In conclusion, based on the demonstration of our study, the SH-SAW biosensor could be a strong candidate for the future measurement of sd-LDL. Full article

SARS-CoV-2, influenza A/B virus (IAV/IBV), and respiratory syncytial virus (RSV) are among the common viruses causing acute respiratory infections. Clinical diagnosis to differentiate these viruses is challenging due to similar clinical presentations; thus, laboratory-based real-time RT PCR is the gold standard for diagnosis. This retrospective study aimed to evaluate the diagnostic performance of STANDARD M10 Flu/RSV/SARS-CoV-2 (SD Biosensor Inc., Seoul, Korea) using archived positive and negative respiratory samples for SARS-CoV-2, IAV, IBV, and RSV. A total of 322 respiratory samples were tested, comprising 215 positive samples (49 SARS-CoV-2, 48 IAV, 53 IBV, 65 RSV) and 107 negative samples. All samples were tested with both STANDARD M10 and compared to either Xpert Xpress SARS-CoV-2 or Xpert Xpress Flu/RSV (Cepheid, Sunnyvale, CA, USA). The sensitivity, specificity, positive predictive value, and negative predictive value rates of STANDARD M10 were very similar to Xpert Xpress SARS-CoV-2 or Xpert Xpress Flu/RSV ranges for each virus (98–100%). The duration of testing and workflows were similar. The overall agreement was 99.4%, including 99.1% agreement for positive samples and 100% agreement for negative samples. In conclusion, the STANDARD M10 point-of-care test is suitable for rapid simultaneous detection of SARS-CoV-2, IAV, IBV, and RSV. Full article

Background: Currently, assessing the diagnostic performance of new laboratory tests assumes a perfect reference standard, which is rarely the case. Wrong classifications of the true disease status will inevitably lead to biased estimates of sensitivity and specificity. Objectives: Using Bayesian’ latent class models (BLCMs), an approach that does not assume a perfect reference standard, we re-analyzed data of a large prospective observational study assessing the diagnostic accuracy of an antigen test for the diagnosis of SARS-CoV-2 infection in clinical practice. Methods: A cohort of consecutive patients presenting to a COVID-19 testing facility affiliated with a Swiss University Hospital were recruited (n = 1465). Two real-time PCR tests were conducted in parallel with the Roche/SD Biosensor rapid antigen test on nasopharyngeal swabs. A two-test (PCR and antigen test), three-population BLCM was fitted to the frequencies of paired test results. Results: Based on the BLCM, the sensitivities of the RT-PCR and the Roche/SD Biosensor rapid antigen test were 98.5% [95% CRI 94.8;100] and 82.7% [95% CRI 66.8;100]. The specificities were 97.7% [96.1;99.7] and 99.9% [95% CRI 99.6;100]. Conclusions: Applying the BLCM, the diagnostic accuracy of RT-PCR was high but not perfect. In contrast to previous results, the sensitivity of the antigen test was higher. Our results suggest that BLCMs are valuable tools for investigating the diagnostic performance of laboratory tests in the absence of perfect reference standard. Full article

(1) Background: With an advanced technique, third-generation sequencing (TGS) provides services with long deoxyribonucleic acid (DNA) reads and super short sequencing time. It enables onsite mobile DNA sequencing solutions for enabling ubiquitous healthcare (U-healthcare) services with modern mobile technology and smart entities in the internet of living things (IoLT). Due to some strict requirements, 6G technology can efficiently facilitate communications in a truly intelligent U-healthcare IoLT system. (2) Research problems: conventional single user–server architecture is not able to enable group conversations where “multiple patients–server” communication or “patient–patient” communication in the group is required. The communications are carried out via the open Internet, which is not a trusted channel. Since heath data and medical information are very sensitive, security and privacy concerns in the communication systems have become extremely important. (3) Purpose: the author aims to propose a dynamic group-based patient-authenticated key distribution protocol for 6G-aided U-healthcare services enabled by mobile DNA sequencing. In the protocol, an authenticated common session key is distributed by the server to the patients. Using the key, patients in a healthcare group are allowed to securely connect with the service provider or with each other for specific purposes of communication. (4) Results: the group key distribution process is protected by a secure three-factor authentication mechanism along with an efficient sequencing-device-based single sign-on (SD-SSO) solution. Based on traceable information stored in the server database, the proposed approach can provide patient-centered services which are available on multiple mobile devices. Security robustness of the proposed protocol is proven by well-known verification tools and a detailed semantic discussion. Performance evaluation shows that the protocol provides more functionality and incurs a reasonable overhead in comparison with the existing works. Full article

In the Amazon, the treatment for Plasmodium vivax is chloroquine plus primaquine. However, this regimen is limited due to the risk of acute hemolytic anemia in glucose-6-phosphate dehydrogenase deficiency. Primaquine is a prodrug that requires conversion by the CYP2D6 enzyme to be effective against malaria. A series of cases were performed at an infectious diseases reference hospital in the Western Brazilian Amazon. The STANDARD G6PD (SD Biosensor^®) assay was used to infer G6PD status and real-time PCR to genotype G6PD, CYP2C19, CYP2D6 and CYP3A4. Eighteen patients were included, of which 55.6% had African A− variant (G202A/A376G), 11.1% African A+ variant (A376G), 5.6% Mediterranean variant (C563T) and 27.8% were wild type. CYP2C19, CYP2D6 and CYP3A4 genotyping showed no statistically significant differences in the frequency of star alleles between the groups G6PD deficient and G6PD normal. Elevated levels of liver and kidney markers in the G6PDd patients were observed in gNM, gRM and gUM of CYP2C19 and CYP2D6 (p < 0.05). Furthermore, in this study there was no influence of CYPs on hemolysis. These findings reinforce the importance of studies on the mapping of G6PD deficiency and genetic variations of CYP2C19, CYP2D6 and CYP3A4. This mapping will allow us to validate the prevalence of CYPs and determine their influence on hemolysis in patients with malaria, helping to decide on the treatment regimen. Full article

We selected a novel biotin-binding peptide for sensing biotin, biotinylated proteins, and nucleotides. From a 15-mer library displayed on the RNA coliphage Qβ, a 15-amino acid long peptide (HGHGWQIPVWPWGQG) hereby referred to as a nanotag was identified to selectively bind biotin. The target selection was achieved through panning with elution by infection. The selected peptide was tested as a transducer for an immunogenic epitope of the foot-and-mouth disease virus (FMDV) on Qβ phage platform separated by a linker. The biotin-tag showed no significant influence on the affinity of the epitope to its cognate antibody (SD6). The nanotag-bound biotin selectively fused either to the C- or N-terminus of the epitope. The epitope would not bind or recognize SD6 while positioned at the N-terminus of the nanotag. Additionally, the biotin competed linearly with the SD6 antibody in a competitive ELISA. Competition assays using the selected recombinant phage itself as a probe or transducer enable the operationalization of this technology as a biosensor toolkit to sense and quantify SD6 analyte. Herein, the published Strep II nanotag (DVEWLDERVPLVET) was used as a control and has similar functionalities to our proposed novel biotin-tag thereby providing a new platform for developing devices for diagnostic purposes. Full article

Electrochemical impedance spectroscopy (EIS) is a sensitive analytical method for surface and bulk properties. Classical EIS and derived electrochemical capacitance spectroscopy (ECS) with a redox couple are label-free approaches for biosensor development, but doubts arise regarding interpretability when a redox couple is employed (redox EIS) due to interactions between electroactive probes and interfacial charges or forced potential. Here, we demonstrated redoxless ECS for directly determining surfactant adsorption on screen-printed carbon electrodes (SPCEs), validated through a simulation of equivalent circuits and the electrochemistry of electronic dummy cells. Redoxless ECS provides excellent capacitance plot loci for quantifying the interfacial permittivity of di-electric layers on electrode surfaces. Redoxless ECS was compared with redox EIS/ECS, revealing a favorable discrimination of interfacial capacitances under both low and high SDS coverage on SPCEs and demonstrating potential for probeless (reagentless) sensing. Furthermore, the proposed method was applied in an electrolyte without a redox couple and bare electrodes, obtaining a high performance for the adsorption of surfactants Tween-20, Triton-X100, sodium dodecyl sulfate, and tetrapropylammonium bromide. This approach offers a simple and straightforward means for a semi-quantitative evaluation of small molecule interactions with electrode surfaces. Our proposed approach may serve as a starting point for future probeless (reagentless) and label-free biosensors based on electrochemistry, eliminating disturbance with surface charge properties and minimizing forced potential bias by avoiding redox couples. An unambiguous and quantitative determination of physicochemical properties of biochemically recognizable layers will be relevant for biosensor development. Full article

Plasmodium vivax cases represent more than 50% of a diminishing malaria case load in Vietnam. Safe and effective radical cure strategies could support malaria elimination by 2030. This study investigated the operational feasibility of introducing point-of-care quantitative glucose-6-phosphate dehydrogenase (G6PD) testing into malaria case management practices. A prospective interventional study was conducted at nine district hospitals and commune health stations in Binh Phuoc and Gia Lai provinces in Vietnam over the period of October 2020 to October 2021. The STANDARD™ G6PD Test (SD Biosensor, Seoul, Republic of Korea) was incorporated to inform P. vivax case management. Case management data and patient and health care provider (HCP) perspectives, as well as detailed cost data were collected. The G6PD test results were interpreted correctly by HCP and the treatment algorithm was adhered to for the majority of patients. One HCP consistently ran the test incorrectly, which was identified during the monitoring and resulted in provision of refresher training and updating of training materials and patient retesting. There was wide acceptability of the intervention among patients and HCP albeit with opportunities to improve the counseling materials. Increasing the number of facilities to which the test was deployed and decreases in the malaria cases resulted in higher per patient cost for incorporating G6PD testing into the system. Commodity costs can be reduced by using the 10-unit kits compared to the 25 unit kits, particularly when the case loads are low. These results demonstrate intervention feasibility while also highlighting specific challenges for a country approaching malaria elimination. Full article

Surfactant-based nanostructures are promising materials for designing novel colorimetric biosensors based on aggregation/disaggregation phenomena. In this work, a colorimetric sensor based on the plasmonic shift of surfactant-capped gold nanoparticles via the disaggregation mechanism was developed. To perform this, the optimum SDS concentration was firstly determined in order to form Au@16-s-16/SDS complex aggregates with a well-defined SPR band in the blue region. Once the optimal SDS concentration for Au@16-s-16 aggregation was established, the sensing method depended on the nature of the electrostatic charge of the biopolymer studied where both the strength of the biopolymer/SDS and biopolymer/Au@16-s-16 interactions and the cationic gold nanoparticles play a key role in the disaggregation processes. As a result, an instantaneous color change from blue to red was gradually observed with increasing biopolymer concentrations. The response of the sensor was immediate, avoiding problems derived from time lapse, and highly dependent on the order of addition of the reagents, with a detection limit in the nanomolar and picomolar range for DNA and Lysozyme sensing, respectively. This behavior can be correlated with the formation of different highly stabilized Au@16-s-16/biopolymer/SDS complexes, in which the particular biopolymer conformation enhances the distance between Au@16-s-16 nanoparticles among the complexes. Full article