Eight biomarkers on a novel strip for early diagnosis of acute myocardial infarction

An integrated electronic tag-based vertical flow assay (e-VFA) with micro-sieve and AlGaN/GaN HEMT sensors for multi-target detection in actual saliva

Vertical flow assay (VFA) is an effective point-of-care (POC) diagnostic tool for widespread application. Nevertheless, the lack of multi-target detection and multi-signal readout capability still remains a challenge. Herein, a brand new VFA scheme for multi-target saliva detection based on electronic tags was proposed, where AlGaN/GaN HEMT sensors modified with different bio-receptors as electronic tags endowed the VFA with multi-target detection capability. In addition, the use of electronic tags instead of optical tags allowed the VFA to simultaneously carry out direct multi-target readouts, which ensure effective POC diagnostics for saliva analysis. Moreover, by integrating a hydrophilically optimized micro-sieve, impurities like sticky filaments, epidermal cells and other large-scale charged particles in saliva were effectively screened, which enabled the direct detection of saliva using AlGaN/GaN HEMT sensors. Glucose, urea, and cortisol were selected to verify the feasibility of the multi-target e-VFA scheme, and the results showed that the limit of detection (LOD) was as low as 100 aM. The linear response was demonstrated in the dynamic range of 100 aM to 100 μM, and the specificity, long-term stability and validity of the actual saliva test were also verified. These results demonstrated that the as-proposed e-VFA has potential for application in saliva detection for simultaneous multi-target detection, and it is expected to achieve the real-time detection of more biological targets in saliva.

Biosensing Platforms for Cardiac Biomarker Detection

Myocardial infarction (MI) is a cardiovascular disease that occurs when there is an elevated demand for myocardial oxygen as a result of the rupture or erosion of atherosclerotic plaques. Globally, the mortality rates associated with MI are steadily on the rise. Traditional diagnostic biomarkers employed in clinical settings for MI diagnosis have various drawbacks, prompting researchers to investigate fast, precise, and highly sensitive biosensor platforms and technologies. Biosensors are analytical devices that combine biological elements with physicochemical transducers to detect and quantify specific compounds or analytes. These devices play a crucial role in various fields including healthcare, environmental monitoring, food safety, and biotechnology. Biosensors developed for the detection of cardiac biomarkers are typically electrochemical, mass, and optical biosensors. Nanomaterials have emerged as revolutionary components in the field of biosensing, offering unique properties that significantly enhance the sensitivity and specificity of the detection systems. This review provides a comprehensive overview of the advancements and applications of nanomaterial-based biosensing systems. Beginning with an exploration of the fundamental principles governing nanomaterials, we delve into their diverse properties, including but not limited to electrical, optical, magnetic, and thermal characteristics. The integration of these nanomaterials as transducers in biosensors has paved the way for unprecedented developments in analytical techniques. Moreover, the principles and types of biosensors and their applications in cardiovascular disease diagnosis are explained in detail. The current biosensors for cardiac biomarker detection are also discussed, with an elaboration of the pros and cons of existing platforms and concluding with future perspectives.

Deep Learning-Enabled Multiplexed Point-of-Care Sensor using a Paper-Based Fluorescence Vertical Flow Assay

Multiplexed computational sensing with a point-of-care serodiagnosis assay to simultaneously quantify three biomarkers of acute cardiac injury is demonstrated. This point-of-care sensor includes a paper-based fluorescence vertical flow assay (fxVFA) processed by a low-cost mobile reader, which quantifies the target biomarkers through trained neural networks, all within <15 min of test time using 50 µL of serum sample per patient. This fxVFA platform is validated using human serum samples to quantify three cardiac biomarkers, i.e., myoglobin, creatine kinase-MB, and heart-type fatty acid binding protein, achieving less than 0.52 ng mL-1 limit-of-detection for all three biomarkers with minimal cross-reactivity. Biomarker concentration quantification using the fxVFA that is coupled to neural network-based inference is blindly tested using 46 individually activated cartridges, which shows a high correlation with the ground truth concentrations for all three biomarkers achieving >0.9 linearity and <15% coefficient of variation. The competitive performance of this multiplexed computational fxVFA along with its inexpensive paper-based design and handheld footprint makes it a promising point-of-care sensor platform that can expand access to diagnostics in resource-limited settings.

Progress in the Optical Sensing of Cardiac Biomarkers

Biomarkers play key roles in the diagnosis, risk assessment, treatment and supervision of cardiovascular diseases (CVD). Optical biosensors and assays are valuable analytical tools answering the need for fast and reliable measurements of biomarker levels. This review presents a survey of recent literature with a focus on the past 5 years. The data indicate continuing trends towards multiplexed, simpler, cheaper, faster and innovative sensing while newer tendencies concern minimizing the sample volume or using alternative sampling matrices such as saliva for less invasive assays. Utilizing the enzyme-mimicking activity of nanomaterials gained ground in comparison to their more traditional roles as signaling probes, immobilization supports for biomolecules and for signal amplification. The growing use of aptamers as replacements for antibodies prompted emerging applications of DNA amplification and editing techniques. Optical biosensors and assays were tested with larger sets of clinical samples and compared with the current standard methods. The ambitious goals on the horizon for CVD testing include the discovery and determination of relevant biomarkers with the help of artificial intelligence, more stable specific recognition elements for biomarkers and fast, cheap readers and disposable tests to facilitate rapid testing at home. As the field is progressing at an impressive pace, the opportunities for biosensors in the optical sensing of CVD biomarkers remain significant.

Effect of miRNA-223-3p Targeting Stromal Interaction Molecule 1 on Proliferation and Apoptosis of Hypoxia/Reoxygenation-Applied H9c2 Cardiomyocytes

This study was established to determine the effect of miRNA-223-3p on the proliferation and apoptosis of hypoxia/reoxygenation-applied H9c2 cardiomyocytes and the associated mechanisms. A hypoxia/reoxygenation (H/R) model was established, with normal cells also used as a control. miRNA-NC, miRNA-223-3p, anti-miRNA-NC, and anti-miRNA-223-3p plasmids were transfected into normally cultured cardiomyocytes, defined as the miRNA-NC, miRNA-223-3p, anti-miRNA-NC, and anti-miRNA-223-3p groups. In addition, miRNA-223-3p was co-transfected into normally cultured cardiomyocytes with pcDNA3.1 and pcDNA3.1-STIM1 plasmids, followed by treatment with H/R for cells in the miR-NC and miR-223-3p groups, defined as the H/R+miRNA-NC, H/R+miRNA-223-3p, H/R+miRNA-223-3p+pcDNA3.1, and H/R+miRNA-223-3p+pcDNA3.1-STIM1 groups. A liposome method was adopted for assessing transfection. qRT-PCR was used to detect miRNA-223-3p expression, while western blotting was used to detect protein expression. MTT assay was used to detect cell viability, flow cytometry to detect apoptosis, and dual luciferase reporter gene assay to detect fluorescence activity. After H/R treatment, miR-223-3p, cyclin D1, and Bcl-2 expression of cardiomyocytes decreased, p21 and Bax expression significantly increased, cell activity decreased, and the apoptosis rate increased. miRNA-223-3p achieved the targeted regulation of STIM1 expression. miRNA-223-3p overexpression promoted the H/R-induced cardiomyocyte proliferation and inhibited cardiomyocyte apoptosis. STIM1 overexpression reversed the proliferation-promoting and apoptosis-inhibiting effects of miRNA-223-3p on cardiomyocytes treated with H/R. The findings show that miRNA-223-3p overexpression promotes H/R-induced cell proliferation, inhibits apoptosis, and protects H/R-induced cardiomyocytes from injury, via a mechanism probably associated with STIM1 expression. miRNA-223-3p thus provides a new target for treating cardiomyocyte injury.

Development of Antibody-Conjugated Gold and Magnetic Nanocomposites for the Colorimetric Detection of Influenza A Virus

A novel approach for the detection of influenza virus is of paramount importance for quick diagnosis and therapy. In this study monoclonal antibody (mAb)-conjugated MNPs/AuNPs were developed to detect the H1N1 virus. MNPs and AuNPs were synthesized and loaded with mAbs. The UV-vis spectra exhibited absorbance at 528 nm. XRD revealed the presence of crystalline particles with various diffraction peaks. FTIR confirmed the occurrence of capping molecules in the synthesized NPs. NP stability was evidenced by zeta measurements. The shape and size (mean size 15 nm) of the NPs were determined using SEM and transmission electron microscopy (TEM). In this study the mAb–AuNPs produced a redshift in the absorption spectrum due to plasmon coupling. The absorption increased when H1N1 concentration increased from 0 to 5.0 ng/mL, with the detection limit being 0.05 ng/mL. The sensitivity of mAb–AuNPs was greater than that of ELISA. Since the mAb-AuNP-based colorimetric immunosensor is simple, cost-effective, and rapidly detects H1N1, it has good prospects in pharmaceuticals and clinical diagnosis.

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

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.

Ultrasensitive chemiluminescence immunoassay with enhanced precision for the detection of cTnI amplified by acridinium ester-loaded microspheres and internally calibrated by magnetic fluorescent nanoparticles

A novel enhanced chemiluminescent immunoassay (CLIA) for ultrasensitive and excellent precisive determination of cardiac troponin I (cTnI) was reported. The method made full use of poly[(N-isopropyl acrylamide)-co-(methacrylic acid)] (P(NIPAM-co-MAA)) microspheres as new potential signal enhancers and magnetic fluorescent nanoparticles as internal standards for better precision. This protocol involved a sandwich format, in which the antigen in the sample was captured by the immobilized antibodies on the surface of magnetic fluorescent beads and recognized by the other antibodies labeled with acridinium ester (AE)-loaded P(NIPAM-co-MAA) microspheres. The combination of the remarkable sensitivity of the enhanced CLIA method and the use of P(NIPAM-co-MAA) microspheres as anti-cTnI carriers for acridinium ester signal amplification provided an extremely sensitive limit of blank (LoB) at 0.097 pg mL^-1, a limit of detection (LoD) at 0.116 pg mL^-1, and a limit of quantitation (LoQ) at 0.606 pg mL^-1, much greater than those achieved by the classical chemiluminescence immunoassay (CLIA, Getein). Moreover, the intra-day variable coefficient can be improved to 1.21-2.12%, and inter-day variability was 2.01-3.49% under the application of magnetic fluorescent beads as an internal standard. The sensitivity and precision have reached a high level, comparable with the current commercial detection kits. The results showed a good correlation with a commercial chemiluminescence assay (CLIA, Abbott), with a correlation coefficient of 0.9883. This proposed method has been successfully applied to the clinical determination of cTnI in the human serum.