Paper microfluidic device for early diagnosis and prognosis of acute myocardial infarction via quantitative multiplex cardiac biomarker detection

Quantitative measurement of acute myocardial infarction cardiac biomarkers by "All-in-One" immune microfluidic chip for early diagnosis of myocardial infarction

Acute myocardial infarction (AMI) is a life-threatening condition with a narrow treatment window, necessitating rapid and accurate diagnostic methods. We present an "all-in-one" convenient and rapid immunoassay system that combines microfluidic technology with a colloidal gold immunoassay. A degassing-driven chip replaces a bulky external pump, resulting in a user-friendly and easy-to-operate immunoassay system. The chip comprises four units: an inlet reservoir, an immunoreaction channel, a waste pool, and an immunocomplex collection chamber, allowing single-channel flow for rapid and accurate AMI biomarker detection. In this study, we focused on cardiac troponin I (cTnI). With a minimal sample of just 4 μL and a total detection time of under 3 min, the chip enabled a quantitative visual analysis of cTnI concentration within a range of 0.5 ∼ 60.0 ng mL-1. This all-in-one integrated microfluidic chip with colloidal gold immunoassay offers a promising solution for rapid AMI diagnosis. The system's portability, small sample requirement, and quantitative visual detection capabilities make it a valuable tool for AMI diagnostics.

Rapid diagnosis of acute myocardial infarction through integrated microfluidic chips for detection of characteristic targets

Myoglobin (Myo), creatine kinase-MB (CKMB), and cardiac troponin I (cTnI) are crucial biomarkers for diagnosing acute myocardial infarction (AMI) The accurate and rapid detection of these three targets can greatly improve the prognosis of AMI patients. Herein, this study developed a microfluidic immunofluorescence method that can detect all three targets in 10-15 min. Ultrasonic atomization and spray technology are used to modify the surface of the injection-molded microfluidic chip (MFC), which effectively solves the problem of biological cross-linking and antibody immobilization on the MFC surface. In addition, it improves the hydrophilicity of the chip surface, thus enhancing fluid self-driving effect. The linear response towards Myo, CKMB and cTnI range from 5 ng/mL to 500 ng/mL, 1 ng/mL to 70 ng/mL, and 0.05 ng/mL to 30 ng/mL, respectively. The intra-batch precision is ≤ 10%, and the inter-batch precision is ≤ 15%. Furthermore, this method shows good consistency compared with the BECKMAN ACCESS2 chemiluminescent immunoanalyzer. The present work provides an AMI diagnostic method with high sensitivity, good repeatability, high accuracy and simple operation, which can satisfy the needs of clinical diagnosis, and shows promising application prospects.

Nanotechnology: The Future for Diagnostic and Therapeutic Intervention in Cardiovascular Diseases is Here

With advances in technology and medicine over the last 3 decades, cardiovascular medicine has evolved tremendously. Nanotechnology provides a promising future in personalized precision medicine. In this review, we delve into the current and prospective applications of nanotechnology and nanoparticles in cardiology. Nanotechnology has allowed for point-of-care testing such as high-sensitivity troponins, as well as more precise cardiac imaging. This review is focused on 3 diseases within cardiology: coronary artery disease, heart failure, and valvular heart disease. The use of nanoparticles in coronary stents has shown success in preventing in-stent thrombosis, as well as using nanosized drug delivery medications to prevent neointimal proliferation in a way that spares systemic toxicity. In addition, by using nanoparticles as drug delivery systems, nanotechnology can be utilized in the delivery of goal-directed medical therapy in heart failure patients. It has also been shown to improve cell therapy in this patient population by helping in cell retention of grafts. Finally, the use of nanoparticles in the manufacturing of bioprosthetic valves provides a promising future for the longevity and success of cardiac valve repair and replacement.

A Microenvironment-responsive small-molecule probe and application in quick acute myocardial infarction imaging

Acute myocardial infarction (AMI) patients are at an elevated risk for life-threatening myocardial ischemia/reperfusion injury. Early-stage nonradioactive and noninvasive diagnosis of AMI is imperative for the subsequent disease treatment, yet it presents substantial challenges. After AMI, the myocardium typically exhibits elevated levels of peroxynitrite (ONOO-), constituting a distinct microenvironmental feature. In this context, the near-infrared imaging probe (BBEB) is employed to precisely delineate the boundaries of AMI lesions with a high level of sensitivity and specificity by monitoring endogenous ONOO-. This probe allows for the early detection of myocardial damage at cellular and animal levels, providing exceptional temporal and spatial resolution. Notably, BBEB enables visualization of ONOO- level alterations during AMI treatment incorporating antioxidant drugs. Overall, BBEB can rapidly and accurately visualize myocardial injury, particularly in the early stages, and can further facilitate antioxidant drug screening.

Telehealth of cardiac devices for CVD treatment

This review covers currently available cardiac implantable electronic devices (CIEDs) as well as updated progress in real-time monitoring techniques for CIEDs. A variety of implantable and wearable devices that can diagnose and monitor patients with cardiovascular diseases are summarized, and various working mechanisms and principles of monitoring techniques for Telehealth and mHealth are discussed. In addition, future research directions are presented based on the rapidly evolving research landscape including Artificial Intelligence (AI).

Smartphone-Aided Fluorescence Detection of Cardiac Biomarker Myoglobin by a Ratiometric Fluorescent AuNCs-QDs Nanohybrids Probe with High Sensitivity

Simple and sensitive detection of cardiac biomarkers is of great significance for early diagnosis and prevention of acute myocardial infarction (AMI). Here, a ratiometric fluorescent nanohybrids probe (AuNCs-QDs) was synthesized through the coupling of bovine serum albumin-functionalized gold nanoclusters (AuNCs) with CdSe/ZnS quantum dots (QDs) to realize simple and sensitive detection of cardiac biomarker myoglobin (Mb). The AuNCs-QDs probe shows pink fluorescence under UV light, with two emission peaks at 468 nm and 630 nm belonging to QDs and AuNCs, respectively. Importantly, the presence of Mb caused fluorescence quenching of the blue-emitting QDs, thereby inhibiting the fluorescence resonance energy transfer (FRET) process between QDs and AuNCs, and reducing the fluorescence intensity ratio (F468/F630) of AuNCs-QDs probe effectively. As the concentration of Mb increases, the ratiometric fluorescent probe also exhibits a visible fluorescence color change. The detection limit was as low as 4.99 μg/mL, and the response of the probe to Mb showed a good linear relationship up to 0.52 mg/mL. Moreover, the probe has excellent specificity for Mb. Besides, the AuNCs-QDs has been applied to detect Mb of urine samples. More importantly, we also developed an AuNCs-QDs probe modified smartphone-aided paper-based strip for on-site monitoring of Mb. As far as we know, this is the first report of a smartphone-aided paper-based strip for on-site quick monitoring of Mb, which provides a useful approach for AMI biomarker monitoring and may can be extended to other medical diagnostics.

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.

Study on myocardial toxicity induced by lead halide perovskites nanoparticles

Lead halide perovskites (LHPs) are outstanding candidates for next-generation optoelectronic materials, with considerable prospects of use and commercial value. However, knowledge about their toxicity is scarce, which may limit their commercialization. Here, for the first time, we studied the cardiotoxicity and molecular mechanisms of representative CsPbBr3 nanoparticles in LHPs. After their intranasal administration to Institute of Cancer Research (ICR) mice, using advanced synchrotron radiation, mass spectrometry, and ultrasound imaging, we revealed that CsPbBr3 nanoparticles can severely affect cardiac systolic function by accumulating in the myocardial tissue. RNA sequencing and Western blotting demonstrated that CsPbBr3 nanoparticles induced excessive oxidative stress in cardiomyocytes, thereby provoking endoplasmic reticulum stress, disturbing calcium homeostasis, and ultimately leading to apoptosis. Our findings highlight the cardiotoxic effects of LHPs and provide crucial toxicological data for the product.

Paper-based multiplex biosensors for inexpensive healthcare diagnostics: a comprehensive review

Multiplex detection is a smart and an emerging approach in point-of-care testing as it reduces analysis time and testing cost by detecting multiple analytes or biomarkers simultaneously which are crucial for disease detection at an early stage. Application of inexpensive substrate such as paper has immense potential and matter of research interest in the area of point of care testing for multiplexed analysis as it possesses several unique advantages. This study presents the use of paper, strategies adopted to refine the design created on paper and lateral flow strips to enhance the signal, increase the sensitivity and specificity of multiplexed biosensors. An overview of different multiplexed detection studies performed using biological samples has also been reviewed along with the challenges and advantages offered by multiplexed analysis.

Recent Advances in Cardiovascular Disease Biosensors and Monitoring Technologies

Cardiovascular disease (CVD) causes significant mortality and remains the leading cause of death globally. Thus, to reduce mortality, early diagnosis by measurement of cardiac biomarkers and heartbeat signals presents fundamental importance. Traditional CVD examination requires bulky hospital instruments to conduct electrocardiography recording and immunoassay analysis, which are both time-consuming and inconvenient. Recently, development of biosensing technologies for rapid CVD marker screening attracted great attention. Thanks to the advancement in nanotechnology and bioelectronics, novel biosensor platforms are developed to achieve rapid detection, accurate quantification, and continuous monitoring throughout disease progression. A variety of sensing methodologies using chemical, electrochemical, optical, and electromechanical means are explored. This review first discusses the prevalence and common categories of CVD. Then, heartbeat signals and cardiac blood-based biomarkers that are widely employed in clinic, as well as their utilizations for disease prognosis, are summarized. Emerging CVD wearable and implantable biosensors and monitoring bioelectronics, allowing these cardiac markers to be continuously measured are introduced. Finally, comparisons of the pros and cons of these biosensing devices along with perspectives on future CVD biosensor research are presented.

SERS spectroscopy with machine learning to analyze human plasma derived sEVs for coronary artery disease diagnosis and prognosis

Coronary artery disease (CAD) is one of the major cardiovascular diseases and represents the leading causes of global mortality. Developing new diagnostic and therapeutic approaches for CAD treatment are critically needed, especially for an early accurate CAD detection and further timely intervention. In this study, we successfully isolated human plasma small extracellular vesicles (sEVs) from four stages of CAD patients, that is, healthy control, stable plaque, non-ST-elevation myocardial infarction, and ST-elevation myocardial infarction. Surface-enhanced Raman scattering (SERS) measurement in conjunction with five machine learning approaches, including Quadratic Discriminant Analysis, Support Vector Machine (SVM), K-Nearest Neighbor, Artificial Neural network, were then applied for the classification and prediction of the sEV samples. Among these five approaches, the overall accuracy of SVM shows the best predication results on both early CAD detection (86.4%) and overall prediction (92.3%). SVM also possesses the highest sensitivity (97.69%) and specificity (95.7%). Thus, our study demonstrates a promising strategy for noninvasive, safe, and high accurate diagnosis for CAD early detection.

Smartphone-based colorimetric detection of cardiac troponin T via label-free aptasensing

We report an aptasensing platform for the detection of cardiac troponin T (cTnT) in the immediate and early phases of acute myocardial infarction (AMI). High-flow filter paper was used to fabricate a microfluidic paper-based analytical device (μ-PAD), which was further modified with gold-decorated polystyrene microparticles functionalized with a highly specific cTnT aptamer. Herein, cTnT detection is presented in two linear ranges (0.01-0.8 μg/ml and 6.25-50 μg/ml) with an LoD of 3.9X10^-4 μg/ml, which is in agreement with reference values determined by the American Heart Association. The proposed platform showed remarkable selectivity against AMI-associated cardiac biomarkers such as TNF-alpha, interleukin-6, cardiac troponin I, and reactive protein-C. This aptasensor is a label-free assay that relies only on smartphone-based image analysis and takes less processing time in comparison with traditional methods like ELISA. Furthermore, it exhibits outstanding stability over 23 days when devices are stored at 4 °C. The reported platform is a stable and cost-effective method for the on-site and user-friendly detection of cTnT in normal saline buffer and diluted human serum.

Rapid simultaneous SERS detection of dual myocardial biomarkers on single-track finger-pump microfluidic chip

Acute myocardial infarction (AMI) is a serious disease with high mortality that afflicts many people around the world. The main cause of death from AMI was the inaccurate early diagnosis, which resulted from the medical treatment might be a delay. Therefore, it is crucial to achieve the rapid detection of AMI. The cardiac troponin I (cTnI) level in human serum may significantly increase as the myocardial membrane ruptured, and the creatine kinase-MB (CK-MB) was also associated with the AMI recurrence and the infarct size of myocardial infarction. Both of them are regarded as important cardiac biomarkers for the early diagnosis of AMI. Therefore, we chose these two cardiac biomarkers as indicators for simultaneous detection. We proposed a single-track finger-pump microfluidic chip for simultaneous surface-enhanced Raman scattering (SERS) detection of cTnI and CK-MB. The entire detection process takes only 5 min without the cumbersome syringe pump. Meanwhile, it enables multiple reagent additions and removals of the unbonded reactants. This microfluidic sensor employed "sandwich" immunoassays based on SERS nanoprobes, AMI biomarkers, and magnetic beads. It is possible to detect two cardiac biomarkers simultaneously in a single measurement, greatly simplifying the detection process and reducing the detection time. Magnetic beads with SERS nanoprobes were separated and captured in the microchamber by a round magnet integrated into the chip. Our results showed that the detection limits of cTnI and CK-MB could reach to 0.01 ng mL^-1, respectively. The limit of detections (LODs) match with the clinical threshold values for AMI biomarkers. It is believed that the proposed single-track finger-pump microfluidic chip can be used as an effective tool for determining early AMI.

Microfluidics for diagnosis and treatment of cardiovascular disease

Cardiovascular disease (CVD), a type of circulatory system disease related to the lesions of the cardiovascular system, has become one of the main diseases that endanger human health. Currently, the clinical diagnosis of most CVDs relies on a combination of imaging technology and blood biochemical test. However, the existing technologies for diagnosis of CVDs still have limitations in terms of specificity, detection range, and cost. In order to break through the current bottleneck, microfluidic with the advantages of low cost, simple instruments and easy integration, has been developed to play an important role in the early prevention, diagnosis and treatment of CVDs. Here, we have reviewed the recent various applications of microfluidic in the clinical diagnosis and treatment of CVDs, including microfluidic devices for detecting CVD markers, the cardiovascular models based on microfluidic, and the microfluidic used for CVDs drug screening and delivery. In addition, we have briefly looked forward to the prospects and challenges of microfluidics in diagnosis and treatment of CVDs.

The association between marathon running and high-sensitivity cardiac troponin: A systematic review and meta-analysis

BACKGROUND

Marathon running is an extreme sport with a distance of about 42 kilometers. Its relationship to high-sensitivity cardiac troponin (hs-cTn) remains controversial.

OBJECTIVE

As the gold standard for detecting myocardial injury, the trends of hs-cTn before and after a marathon were investigated and analyzed.

METHODS

A literature search was conducted in PubMed, EMBASE, and Cochrane Library databases by combing the keywords marathon and troponin, and studies regarding high-sensitivity cardiac troponin I (hs-cTnI) and high-sensitivity cardiac troponin T (hs-cTnT) concentrations before and after marathon running (not for half-marathon and ultra-marathon) were included. "Quality Assessment Tool for Before-After (Pre-Post) Studies With No Control Group" were used to assess the risk of bias. Statistical analysis was performed using Review Manager, presenting data as mean values and 95% confidence intervals (CIs). Sensitivity analysis and subgroup analysis were performed if there was high heterogeneity among studies based on I2 statistic.

RESULTS

A total of 13 studies involving 824 marathoners were included in this systematic review and meta-analysis. Both hs-cTnI (MD 68.79 ng/L, [95% CI 53.22, 84.37], p< 0.001) and hs-cTnT (MD 42.91 ng/L, [95% CI 30.39, 55.43], p< 0.001) were elevated after running a marathon, but the concentration of hs-cTnT returned to baseline after 72 to 96 h post-race (MD 0.11 ng/L, [95% CI -1.30, 1.52], p= 0.88). The results of subgroup analysis demonstrated that the 99th percentile upper reference limit of hs-cTnT might be the source of heterogeneity.

CONCLUSION

The concentrations of hs-cTnI and hs-cTnT were increased after marathon running, but the change of hs-cTnT is usually not seen as irreversible myocardial injury.

Patchouli alcohol protects against myocardial ischaemia-reperfusion injury by regulating the Notch1/Hes1 pathway

CONTEXT

Patchouli alcohol (PA) has protective effects on cerebral ischaemia/reperfusion (I/R) injury, but its efficacy on myocardial ischaemia-reperfusion (MI/R) has yet to be addressed.

OBJECTIVE

To examine the therapeutic effect of PA on myocardial ischaemia-reperfusion (I/R) injury.

MATERIALS AND METHODS

C57BL/6 male mice were randomly divided into sham, MI/R, MI/R + PA-10, MI/R + PA-20 and MI/R + PA-40 groups. In vivo MI/R model was established by ligating the anterior descending coronary artery of the heart. In vitro stimulated IR cell model was constructed by using the rat cardiomyocyte H9C2 cell line. Mice in the treatment groups were intraperitoneally injected with PA (10, 20, 40 mg/kg) for 30 days then subjected to surgery, and cells in the experimental group were pre-treated with PA (1, 10 or 100 μmol/L). After treatment, mouse heart function, myocardial injury markers, myocardial infarction and Notch1/Hes1 expression, endoplasmic reticulum stress markers, and apoptosis-related proteins were determined.

RESULTS

In vivo, PA treatment improved hemodynamic parameter changes and myocardial enzymes, increased the left ventricular ejection fraction and left ventricular fractional shortening, reduced the left ventricular end-systolic diameter and inhibited CK-MB, cTnI and cTnT levels. In addition, PA attenuated myocardial tissue damage and apoptosis. PA treatment elevated Notch1, NICD and Hes1 levels and suppressed the levels of ATF4, p-PERK/PERK, and cleaved caspase-3/caspase-3 in vitro and in vivo.

DISCUSSION AND CONCLUSION

PA protects against MI/R, possibly by modulating ER stress, apoptosis and the Notch1/Hes1 signalling pathways. These findings indicate that PA may be a promising candidate for treating ischaemic heart diseases.

Biosensors for the Rapid Detection of Cardiovascular Biomarkers of Vital Interest: Needs, Analysis and Perspectives

We have previously surveyed a panel of 508 physicians from around the world about which biomarkers would be relevant if obtained in a very short time frame, corresponding to emergency situations (life-threatening or not). The biomarkers that emerged from this study were markers of cardiovascular disease: troponin, D-dimers, and brain natriuretic peptide (BNP). Cardiovascular disease is a group of disorders affecting the heart and blood vessels. At the intersection of medicine, basic research and engineering, biosensors that address the need for rapid biological analysis could find a place of choice in the hospital or primary care ecosystem. Rapid, reliable, and inexpensive analysis with a multi-marker approach, including machine learning analysis for patient risk analysis, could meet the demand of medical teams. The objective of this opinion review, proposed by a multidisciplinary team of experts (physicians, biologists, market access experts, and engineers), is to present cases where a rapid biological response is indeed valuable, to provide a short overview of current biosensor technologies for cardiac biomarkers designed for a short result time, and to discuss existing market access issues.

Biomedical Applications of Microfluidic Devices: A Review

Both passive and active microfluidic chips are used in many biomedical and chemical applications to support fluid mixing, particle manipulations, and signal detection. Passive microfluidic devices are geometry-dependent, and their uses are rather limited. Active microfluidic devices include sensors or detectors that transduce chemical, biological, and physical changes into electrical or optical signals. Also, they are transduction devices that detect biological and chemical changes in biomedical applications, and they are highly versatile microfluidic tools for disease diagnosis and organ modeling. This review provides a comprehensive overview of the significant advances that have been made in the development of microfluidics devices. We will discuss the function of microfluidic devices as micromixers or as sorters of cells and substances (e.g., microfiltration, flow or displacement, and trapping). Microfluidic devices are fabricated using a range of techniques, including molding, etching, three-dimensional printing, and nanofabrication. Their broad utility lies in the detection of diagnostic biomarkers and organ-on-chip approaches that permit disease modeling in cancer, as well as uses in neurological, cardiovascular, hepatic, and pulmonary diseases. Biosensor applications allow for point-of-care testing, using assays based on enzymes, nanozymes, antibodies, or nucleic acids (DNA or RNA). An anticipated development in the field includes the optimization of techniques for the fabrication of microfluidic devices using biocompatible materials. These developments will increase biomedical versatility, reduce diagnostic costs, and accelerate diagnosis time of microfluidics technology.

Flexible biochemical sensors for point-of-care management of diseases: a review

Health problems have been widely concerned by all mankind. Real-time monitoring of disease-related biomarkers can feedback the physiological status of human body in time, which is very helpful to the diseases management of healthcare. However, conventional non-flexible/rigid biochemical sensors possess low fit and comfort with the human body, hence hindering the accurate and comfortable long-time health monitoring. Flexible and stretchable materials make it possible for sensors to be continuously attached to the human body with good fit, and more precise and higher quality results can be obtained. Thus, tremendous attention has been paid to flexible biochemical sensors in point-of-care (POC) for real-time monitoring the entire disease process. Here, recent progress on flexible biochemical sensors for management of various diseases, focusing on chronic and communicable diseases, is reviewed, and the detection principle and performance of these flexible biochemical sensors are discussed. Finally, some directions and challenges are proposed for further development of flexible biochemical sensors.

Fluid biomarkers in stroke: From animal models to clinical care

Stroke is a leading cause of death and disability worldwide. Stroke prevention, early diagnosis, and efficient acute treatment are priorities to successfully impact stroke death and disability. Fluid biomarkers may improve stroke differential diagnostic, patient stratification for acute treatment, and post-stroke individualized rehabilitation. In the present work, we characterized the use of stroke animal models in fluid biomarker research through a systematic review of PubMed and Scopus databases, followed by a literature review on the translation to the human stroke care setting and future perspectives in the field. We found increasing numbers of publications but with limited translation to the clinic. Animal studies are very heterogeneous, do not account for several human features present in stroke, and, importantly, only a minority of such studies used human cohorts to validate biomarker findings. Clinical studies have found appealing candidates, both protein and circulating nucleic acids, to contribute to a more personalized stroke care pathway. Still, brain tissue complexity and the fact that different brain pathologies share lesion biomarkers make this task challenging due to biomarker low specificity. Moreover, the study design and lack of validation cohorts may have precluded a formal integration of biomarkers in different steps of stroke diagnosis and treatment. To overcome such issues, recent pivotal studies on biomarker dynamics in individual patients are providing added value to diagnosis and anticipating patients' early prognosis. Presently, the most consistent protein biomarkers for stroke diagnosis and short- and long-term prognosis are associated with tissue damage at neuronal (TAU), axonal (NFL), or astroglial (GFAP and S100β) levels. Most promising nucleic acids are microRNAs (miR), due to their stability in plasma and ease of access. Still, clinical validation and standardized quantitation place them a step behind compared protein as stroke biomarkers. Ultimately, the definition of clinically relevant biomarker panels and optimization of fast and sensitive biomarker measurements in the blood, together with their combination with clinical and neuroimaging data, will pave the way toward personalized stroke care.

Cardiac Troponin Biosensor Designs: Current Developments and Remaining Challenges

Acute myocardial infarction (AMI) is considered as one of the main causes of death, threating human lives for decades. Currently, its diagnosis relies on electrocardiography (ECG), which has been proven to be insufficient. In this context, the efficient detection of cardiac biomarkers was proposed to overcome the limitations of ECG. In particular, the measurement of troponins, specifically cardiac troponin I (cTnI) and cardiac troponin T (cTnT), has proven to be superior in terms of sensitivity and specificity in the diagnosis of myocardial damage. As one of the most life-threatening conditions, specific and sensitive investigation methods that are fast, universally available, and cost-efficient to allow for early initiation of evidence-based, living-saving treatment are desired. In this review, we aim to present and discuss the major breakthroughs made in the development of cTnI and cTnT specific biosensor designs and analytical tools, highlighting the achieved progress as well as the remaining challenges to reach the technological goal of simple, specific, cheap, and portable testing chips for the rapid and efficient on-site detection of cardiac cTnI/cTnT biomarkers in order to diagnose and treat cardiovascular diseases at an incipient stage.

Photoelectrochemical sandwich immunoassay of brain glycogen phosphorylase based on methyl orange-sensitized TiO2 nanorods

The photoelectrochemical immunoassay of glycogen phosphorylase BB (GPBB) was studied. A methyl orange/TiO₂ nanorod heterojunction was constructed on a fluorine-doped tin oxide electrode by hydrothermal synthesis, calcination, and chemical adsorption. A sandwich immune structure consisting of GPBB as the first antibody, GPBB, and a CdS@mesoporous silica-ascorbic acid (AA)-GPBB as secondary antibody composite was constructed on each of the selected well surfaces of a 96-well microplate. By adding mercaptoethylamine to structurally destroy the secondary antibody composite and release the electron donor AA, the amplification of photocurrent, and thus the "off-on" photoelectrochemical biosensing of GPBB were realized. The use of the 96-well microplate provides good reproducibility of the assembled immune structures and eliminates the possible effect of the photogenerated hole-induced protein oxidation on the photocurrent. The relevant electrodes and materials were characterized by electrochemistry, UV-vis diffuse reflectance spectra, Fourier transform infrared spectroscopy, X-ray diffractometer, scanning electron microscopy/energy dispersive spectroscopy, transmission electron microscopy and BET method. Under the optimal conditions, the photocurrent was linear with the logarithm of GPBB concentration from 0.005 to 200 ng mL^-1 and with a limit of detection of 1.7 pg mL^-1 (S/N = 3). Satisfactory results were obtained in the analysis of real serum samples. A sandwich immune structure consisting of GPBB first antibody, GPBB, and a CdS@mesoporous silica-ascorbic acid (AA)-GPBB secondary antibody composite was constructed on each of the selected well surfaces of a 96-well microplate. By adding mercaptoethylamine to structurally destroy the secondary antibody composite and release the electron donor AA, the amplification of photocurrent, and thus the "off-on" photoelectrochemical biosensing of GPBB were realized.

Diagnostic accuracy of glycogen phosphorylase BB for myocardial infarction: A systematic review and meta-analysis

PURPOSE

We tried to investigate the diagnostic accuracy of glycogen phosphorylase BB as a cardiac marker for myocardial infarction.

METHODS

We searched through different electronic databases (PubMed, Google-scholar, Embase, and Cochrane Library) to locate relevant articles. Studies, with sufficient data to reconstruct a 2 × 2 contingency table, met our inclusion criteria were included. Three reviewers independently screened the articles. Discrepancies were resolved by other reviewers. Unpublished data were requested from the authors of the study via email. Subsequently, data extraction was done using a standardized form and quality assessment of studies using the QUADAS-2 tool. Meta-analysis was done using a bivariate model using R software.

RESULTS

Fourteen studies were selected for the final evaluation, which yielded the summary points: pooled sensitivity 87.77% (77.52%-93.72%, I2  = 86%), pooled specificity 88.45% (75.59%-94.99%, I2  = 88%), pooled DOR 49.37(14.53-167.72, I2  = 89%), and AUC of SROC was 0.923. The lambda value of the HSROC curve was 3.670. The Fagan plot showed that GPBB increases the pretest probability of myocardial infarction from 46% to 81% when positive, and it lowers the same probability to 12% when negative.

CONCLUSION

With these results, we can conclude that GPBB has modest accuracy in screening myocardial infarction, but the limitations of the study warrant further high-quality studies to confirm its usefulness in predicting myocardial infarction (MI).

Microfluidic Point-of-Care (POC) Devices in Early Diagnosis: A Review of Opportunities and Challenges

The early diagnosis of infectious diseases is critical because it can greatly increase recovery rates and prevent the spread of diseases such as COVID-19; however, in many areas with insufficient medical facilities, the timely detection of diseases is challenging. Conventional medical testing methods require specialized laboratory equipment and well-trained operators, limiting the applicability of these tests. Microfluidic point-of-care (POC) equipment can rapidly detect diseases at low cost. This technology could be used to detect diseases in underdeveloped areas to reduce the effects of disease and improve quality of life in these areas. This review details microfluidic POC equipment and its applications. First, the concept of microfluidic POC devices is discussed. We then describe applications of microfluidic POC devices for infectious diseases, cardiovascular diseases, tumors (cancer), and chronic diseases, and discuss the future incorporation of microfluidic POC devices into applications such as wearable devices and telemedicine. Finally, the review concludes by analyzing the present state of the microfluidic field, and suggestions are made. This review is intended to call attention to the status of disease treatment in underdeveloped areas and to encourage the researchers of microfluidics to develop standards for these devices.

Nanotechnology for Cardiovascular Diseases

Cardiovascular diseases have become the major killers in today's world, among which coronary artery diseases (CADs) make the greatest contributions to morbidity and mortality. Although state-of-the-art technologies have increased our knowledge of the cardiovascular system, the current diagnosis and treatment modalities for CADs still have limitations. As an emerging cross-disciplinary approach, nanotechnology has shown great potential for clinical use. In this review, recent advances in nanotechnology in the diagnosis of CADs will first be elucidated. Both the sensitivity and specificity of biosensors for biomarker detection and molecular imaging strategies, such as magnetic resonance imaging, optical imaging, nuclear scintigraphy, and multimodal imaging strategies, have been greatly increased with the assistance of nanomaterials. Second, various nanomaterials, such as liposomes, polymers (PLGA), inorganic nanoparticles (AuNPs, MnO₂, etc.), natural nanoparticles (HDL, HA), and biomimetic nanoparticles (cell-membrane coating) will be discussed as engineered as drug (chemicals, proteins, peptides, and nucleic acids) carriers targeting pathological sites based on their optimal physicochemical properties and surface modification potential. Finally, some of these nanomaterials themselves are regarded as pharmaceuticals for the treatment of atherosclerosis because of their intrinsic antioxidative/anti-inflammatory and photoelectric/photothermal characteristics in a complex plaque microenvironment. In summary, novel nanotechnology-based research in the process of clinical transformation could continue to expand the horizon of nanoscale technologies in the diagnosis and therapy of CADs in the foreseeable future.

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Nanotechnology represents new viable approaches for diagnosis and treatment of cardiovascular diseases, the leading cause of morbidity and mortality worldwide

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Nanotechnology-assisted biosensing and molecular imaging can improve the sensitivity and specificity in the diagnosis of cardiovascular diseases

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Nanomaterials enable targeted drug delivery or directly exert therapeutic action for cardiovascular system, based on their physicochemical properties and surface modification

Advances in multiplex electrical and optical detection of biomarkers using microfluidic devices

Microfluidic devices can provide a versatile, cost-effective platform for disease diagnostics and risk assessment by quantifying biomarkers. In particular, simultaneous testing of several biomarkers can be powerful. Here, we critically review work from the previous 4 years up to February 2021 on developing microfluidic devices for multiplexed detection of biomarkers from samples. We focus on two principal approaches: electrical and optical detection methods that can distinguish and quantify biomarkers. Both electrical and spectroscopic multiplexed detection strategies are being employed to reach limits of detection below clinical sample levels. Some of the most promising strategies for point-of-care assays involve inexpensive materials such as paper-based microfluidic devices, or portable and accessible detectors such as smartphones. This review does not comprehensively cover all multiplexed microfluidic biomarker studies, but rather provides a critical evaluation of key work and suggests promising prospects for future advancement in this field. Electrical and optical multiplexing are powerful approaches for microfluidic biomarker analysis.

Regenerative strategies for the consequences of myocardial infarction: Chronological indication and upcoming visions

Heart muscle injury and an elevated troponin level signify myocardial infarction (MI), which may result in defective and uncoordinated segments, reduced cardiac output, and ultimately, death. Physicians apply thrombolytic therapy, coronary artery bypass graft (CABG) surgery, or percutaneous coronary intervention (PCI) to recanalize and restore blood flow to the coronary arteries, albeit they were not convincingly able to solve the heart problems. Thus, researchers aim to introduce novel substitutional therapies for regenerating and functionalizing damaged cardiac tissue based on engineering concepts. Cell-based engineering approaches, utilizing biomaterials, gene, drug, growth factor delivery systems, and tissue engineering are the most leading studies in the field of heart regeneration. Also, understanding the primary cause of MI and thus selecting the most efficient treatment method can be enhanced by preparing microdevices so-called heart-on-a-chip. In this regard, microfluidic approaches can be used as diagnostic platforms or drug screening in cardiac disease treatment. Additionally, bioprinting technique with whole organ 3D printing of human heart with major vessels, cardiomyocytes and endothelial cells can be an ideal goal for cardiac tissue engineering and remarkable achievement in near future. Consequently, this review discusses the different aspects, advancements, and challenges of the mentioned methods with presenting the advantages and disadvantages, chronological indications, and application prospects of various novel therapeutic approaches.

Recent Advances in Cardiac Tissue Engineering for the Management of Myocardium Infarction

Myocardium Infarction (MI) is one of the foremost cardiovascular diseases (CVDs) causing death worldwide, and its case numbers are expected to continuously increase in the coming years. Pharmacological interventions have not been at the forefront in ameliorating MI-related morbidity and mortality. Stem cell-based tissue engineering approaches have been extensively explored for their regenerative potential in the infarcted myocardium. Recent studies on microfluidic devices employing stem cells under laboratory set-up have revealed meticulous events pertaining to the pathophysiology of MI occurring at the infarcted site. This discovery also underpins the appropriate conditions in the niche for differentiating stem cells into mature cardiomyocyte-like cells and leads to engineering of the scaffold via mimicking of native cardiac physiological conditions. However, the mode of stem cell-loaded engineered scaffolds delivered to the site of infarction is still a challenging mission, and yet to be translated to the clinical setting. In this review, we have elucidated the various strategies developed using a hydrogel-based system both as encapsulated stem cells and as biocompatible patches loaded with cells and applied at the site of infarction.

Electrochemical strategies for the detection of cTnI

Acute myocardial infarction (AMI) is the main cause of death from cardiovascular diseases. Thus, early diagnosis of AMI is essential for the treatment of irreversible damage from myocardial infarction. Traditional electrocardiograms (ECG) cannot meet the specific detection of AMI. Cardiac troponin I (cTnI) is the main biomarker for the diagnosis of myocardial infarction, and the detection of cTnI content has become particularly important. In this review, we introduced and compared the advantages and disadvantages of various cTnI detection methods. We focused on the analysis and comparison of the main indicators and limitations of various cTnI biosensors, including the detection range, detection limit, specificity, repeatability, and stability. In particular, we pay more attention to the application and development of electrochemical biosensors in the diagnosis of cardiovascular diseases based on different biological components. The application of electrochemical microfluidic chips for cTnI was also briefly introduced in this review. Finally, this review also briefly discusses the unresolved challenges of electrochemical detection and the expectations for improvement in the detection of cTnI biosensing in the future.

A review of risk prediction models in cardiovascular disease: conventional approach vs. artificial intelligent approach

Cardiovascular disease (CVD) is the leading cause of death worldwide and is a global health issue. Traditionally, statistical models are used commonly in the risk prediction and assessment of CVD. However, the adoption of artificial intelligent (AI) approach is rapidly taking hold in the current era of technology to evaluate patient risks and predict the outcome of CVD. In this review, we outline various conventional risk scores and prediction models and do a comparison with the AI approach. The strengths and limitations of both conventional and AI approaches are discussed. Besides that, biomarker discovery related to CVD are also elucidated as the biomarkers can be used in the risk stratification as well as early detection of the disease. Moreover, problems and challenges involved in current CVD studies are explored. Lastly, future prospects of CVD risk prediction and assessment in the multi-modality of big data integrative approaches are proposed.

Vitamin D Deficiency as a Risk Factor for Myocardial Ischemia

Background and Objectives: Vitamin D (Vit D) deficiency has been implicated in various conditions, including cardiovascular disease. The purpose of this retrospective study was to investigate the incidence of patients with myocardial ischemia in relation to their serum levels of vitamin D. Materials and Methods: A 64-month search (January 2016 to April 2021) in our database of the Nuclear Medicine Laboratory revealed 113 patients who had both myocardial perfusion imaging with single photon emission computed tomography (MPI SPECT) and Vit D measurements. MPI SPECT obtained myocardial images during both stress (summed stress score, SSS) and rest (summed rest score, SRS). Abnormal MPI SPECT was when the SSS was ≥4. Vit D was determined by radioimmunoassay (RIA). Patients with Vit D values <10 ng/mL, 10-29 ng/mL and ≥30 ng/mL were defined as having a deficiency, insufficiency and sufficiency, respectively. Results: Among patients, 46/113 (40.7%) were male and 67/113 (59.3%) were female. Abnormal MPI was found in 58/113 (51.3%) patients. Vit D deficiency was noted in 20/113 (17.7%) patients, insufficiency in 86/113 (76.1%) patients, and normal Vit D was noted in only 7/113 (6.2%) patients. Sixteen of the 20 patients (80%) with Vit D deficiency, and 38/86 (44.2%) with insufficiency had an abnormal MPI SPECT. In contrast, only 1/7 (14.3%) patients with sufficient Vit D levels had an abnormal MPI SPECT. The Mann-Whitney U-test showed that ischemia reduced the values of Vit D. Correlation analysis showed a negative association of Vit D levels with SSS (rho = -0.232, p = 0.014) and SRS (rho = -0.250, p = 0.008). Further evaluation with a Vit D cut off 20 ng/mL retrieved no statistical significance. Finally, Vit D and gender were independently associated with myocardial ischemia. Conclusions: Low Vit D levels may represent a risk factor for myocardial ischemia.

Magnetic nanochains-based dynamic ELISA for rapid and ultrasensitive detection of acute myocardial infarction biomarkers

Acute myocardial infarction (AMI) is the leading cause of morbidity and mortality globally. The serum levels of a group of cardiac biomarkers have been regarded as important indicators in the routine diagnosis of AMI. The development of rapid, sensitive, and accurate detection methods of AMI biomarkers is urgently needed for the early diagnosis of AMI. Here, a dynamic and pseudo-homogeneous enzyme-linked immunosorbent assay (ELISA) was reported based on the combined use of bioconjugated magnetic nanochains (MNCs) and gold nanoparticles (AuNPs) probes. The capture antibodies-conjugated MNCs served as dynamic nano-mixers to facilitate liquid mixing and as homogeneously dispersed capturing agents to capture and separate specific targets. The AuNPs probes were prepared by co-immobilization of detection antibodies and horseradish peroxidase (HRP) for signals amplification. The design of bioconjugated MNCs and AuNPs probes significantly increased the assay kinetics and improves the assay sensitivity. This novel ELISA strategy realized accurate detection of a panel of AMI biomarkers within 35 min, leading to considerably improved sensitivities compared to that of conventional ELISA method.

Recent advances in lab-on-paper diagnostic devices using blood samples

Lab-on-paper, or microfluidic paper-based analytical devices (μPADs), use paper as a substrate material, and are patterned with a system of microchannels, reaction zones and sensing elements to perform analysis and detection. The sample transfer in such devices is performed by capillary action. As a result, external driving forces are not required, and hence the size and cost of the device are significantly reduced. Lab-on-paper devices have thus attracted significant attention for point-of-care medical diagnostic purposes in recent years, particularly in less-developed regions of the world lacking medical resources and infrastructures. This review discusses the major advances in lab-on-paper technology for blood analysis and diagnosis in the past five years. The review focuses particularly on the many clinical applications of lab-on-paper devices, including diabetes diagnosis, acute myocardial infarction (AMI) detection, kidney function diagnosis, liver function diagnosis, cholesterol and triglyceride (TG) analysis, sickle-cell disease (SCD) and phenylketonuria (PKU) analysis, virus analysis, C-reactive protein (CRP) analysis, blood ion analysis, cancer factor analysis, and drug analysis. The review commences by introducing the basic transmission principles, fabrication methods, structural characteristics, detection techniques, and sample pretreatment process of modern lab-on-paper devices. A comprehensive review of the most recent applications of lab-on-paper devices to the diagnosis of common human diseases using blood samples is then presented. The review concludes with a brief summary of the main challenges and opportunities facing the lab-on-paper technology field in the coming years.

Rapid, sensitive universal paper-based device enhances competitive immunoassays of small molecules

Competitive immunoassays comprise the standard means of detecting small molecules. However, conventional methods using microwells are difficult to apply during point-of-care tests (POCT) because they require complicated handling and are time consuming. Although paper-based analytical devices (PAD) have received considerable focus because of their rapid and straightforward operation, only a few devices have been proposed for competitive immunoassays. Herein, we describe a novel universal PAD format with a 3-dimensional configuration for competitive immunoassays that rapidly and sensitively detects small molecules. The proposed device comprised a layered structure with uniform color formation and high capture efficiency between antigen and antibody that results in rapid and reproducible results. The device rapidly (90 s) assayed biotin as a model target, with a limit of detection (LOD) of 5.08 ng mL^-1, and detected progesterone with an LOD of 84 pg mL^-1 within 5 min. Moreover, sample volumes and reagent consumption rates were minimized. Thus, our device could be applied to competitive immunoassays of various small molecules in POCT.

Emerging point-of-care biosensors for rapid diagnosis of COVID-19: current progress, challenges, and future prospects

Coronavirus disease 2019 (COVID-19) pandemic is currently a serious global health threat. While conventional laboratory tests such as quantitative real-time polymerase chain reaction (qPCR), serology tests, and chest computerized tomography (CT) scan allow diagnosis of COVID-19, these tests are time-consuming and laborious, and are limited in resource-limited settings or developing countries. Point-of-care (POC) biosensors such as chip-based and paper-based biosensors are typically rapid, portable, cost-effective, and user-friendly, which can be used for COVID-19 in remote settings. The escalating demand for rapid diagnosis of COVID-19 presents a strong need for a timely and comprehensive review on the POC biosensors for COVID-19 that meet ASSURED criteria: Affordable, Sensitive, Specific, User-friendly, Rapid and Robust, Equipment-free, and Deliverable to end users. In the present review, we discuss the importance of rapid and early diagnosis of COVID-19 and pathogenesis of COVID-19 along with the key diagnostic biomarkers. We critically review the most recent advances in POC biosensors which show great promise for the detection of COVID-19 based on three main categories: chip-based biosensors, paper-based biosensors, and other biosensors. We subsequently discuss the key benefits of these biosensors and their use for the detection of antigen, antibody, and viral nucleic acids. The commercial POC biosensors for COVID-19 are critically compared. Finally, we discuss the key challenges and future perspectives of developing emerging POC biosensors for COVID-19. This review would be very useful for guiding strategies for developing and commercializing rapid POC tests to manage the spread of infections.Graphical abstract.

Increasing the packing density of assays in paper-based microfluidic devices

Paper-based devices have a wide range of applications in point-of-care diagnostics, environmental analysis, and food monitoring. Paper-based devices can be deployed to resource-limited countries and remote settings in developed countries. Paper-based point-of-care devices can provide access to diagnostic assays without significant user training to perform the tests accurately and timely. The market penetration of paper-based assays requires decreased device fabrication costs, including larger packing density of assays (i.e., closely packed features) and minimization of assay reagents. In this review, we discuss fabrication methods that allow for increasing packing density and generating closely packed features in paper-based devices. To ensure that the paper-based device is low-cost, advanced fabrication methods have been developed for the mass production of closely packed assays. These emerging methods will enable minimizing the volume of required samples (e.g., liquid biopsies) and reagents in paper-based microfluidic devices.

Recent advances in cardiac biomarkers detection: From commercial devices to emerging technologies

Although cardiac pathologies are the major cause of death in the world, it remains difficult to provide a reliable diagnosis to prevent heart attacks. Rapid patient care and management in emergencies are critical to prevent dramatic consequences. Thus, relevant biomarkers such as cardiac troponin and natriuretic peptides are currently targeted by commercialized Point-Of-Care immunoassays. Key points still to be addressed concern cost, lack of standardization, and poor specificity, which could limit the reliability of the assays. Consequently, alternatives are emerging to address these issues. New probe molecules such as aptamers or molecularly imprinted polymers should allow a reduction in cost of the assays and an increase in reproducibility. In addition, the assay specificity and reliability could be improved by enabling multiplexing through the detection of several molecular targets in a single device.

Gold Nanoparticle-Based Platforms for Diagnosis and Treatment of Myocardial Infarction

In recent years, an increasing rate of mortality due to myocardial infarction (MI) has led to the development of nanobased platforms, especially gold nanoparticles (AuNPs), as promising nanomaterials for diagnosis and treatment of MI. These promising NPs have been used to develop different nanobiosensors, mainly optical sensors for early detection of biomarkers as well as biomimetic/bioinspired platforms for cardiac tissue engineering (CTE). Therefore, in this Review, we presented an overview on the potential application of AuNPs as optical (surface plasmon resonance, colorimetric, fluorescence, and chemiluminescence) nanobiosensors for early diagnosis and prognosis of MI. On the other hand, we discussed the potential application of AuNPs either alone or with other NPs/polymers as promising three-dimensional (3D) scaffolds to regulate the microenvironment and mimic the morphological and electrical features of cardiac cells for potential application in CTE. Furthermore, we presented the challenges and ongoing efforts associated with the application of AuNPs in the diagnosis and treatment of MI. In conclusion, this Review may provide outstanding information regarding the development of AuNP-based technology as a promising platform for current MI treatment approaches.

Acute Myocardial Infarction Biosensor: A Review From Bottom Up

Acute myocardial infarction (AMI) is a cardiovascular disease that is produced due to a deficiency of oxygen generating irreversible damage in the heart muscle. In diagnosis, electrocardiogram (ECG) investigation has been the main method but is insufficient, so approaches like the measurement of biomarkers levels in plasma or saliva have become one of the most commonly applied strategies for prognosis of AMI, as some of them are specifically related to a heart attack. Many tests are carrying on to determine biological markers changes, but usually, they present disadvantages related to time consumption and laborious work. To overcome the issues, researchers around the world have been developing different ways to enhance detection through the use of biosensors. These diagnostic devices have a biological sensing element associated to a physicochemical transducer that can be made from different materials and configurations giving place to different kinds of detection: Electrical/Electrochemical, Optical and Mechanical. In this review, the authors presents relevant investigations related to the most important biomarkers and biosensors used for their detection having in mind the nanotechnology participation in the process through the application of nanostructures as a good choice for device configuration.

Nanodiamonds and hydrogen-substituted graphdiyne heteronanostructure for the sensitive impedimetric aptasensing of myocardial infarction and cardiac troponin I

A novel heteronanostructure of nanodiamonds (NDs) and hydrogen-substituted graphdiyne (HsGDY) (denoted as HsGDY@NDs) was prepared for the impedimetric aptasensing of biomarkers such as myoglobin (Myo) and cardiac troponin I (cTnI). Basic characterizations revealed that the HsGDY@NDs were composed of nanospheres with sizes of 200-500 nm. In these nanospheres, NDs were embedded within the HsGDY network. The HsGDY@NDs nanostructure, which integrated the good chemical stability and three-dimensional porous networks of HsGDY, and the good biocompatibility and electrochemical activity of NDs, could immobilize diverse aptamer strands and recognize target biomarkers. Compared with HsGDY- and NDs-based aptasensors, the HsGDY@NDs-based aptasensors exhibited superior sensing performances for Myo and cTnI, giving low detection limits of 6.29 and 9.04 fg mL^-1 for cTnI and Myo, respectively. In addition, the HsGDY@NDs-based aptasensors exhibited high selectivity, good stability, reproducibility, and acceptable applicability in real human serum. Thus, the construction of HsGDY@NDs-based aptasensor is expected to broaden the application of porous organic frameworks in the sensing field and provide a prospective approach for the early detection of disease biomarkers.

Biosensing based on surface-enhanced Raman spectroscopy as an emerging/next-generation point-of-care approach for acute myocardial infarction diagnosis

Cardiovascular disease is a major global health issue. In particular, acute myocardial infarction (AMI) requires urgent attention and early diagnosis. The use of point-of-care diagnostics has resulted in the improved management of cardiovascular disease, but a major drawback is that the performance of POC devices does not rival that of central laboratory tests. Recently, many studies and advances have been made in the field of surface-enhanced Raman scattering (SERS), including the development of POC biosensors that utilize this detection method. Here, we present a review of the strengths and limitations of these emerging SERS-based biosensors for AMI diagnosis. The ability of SERS to multiplex sensing against existing POC detection methods are compared and discussed. Furthermore, SERS calibration-free methods that have recently been explored to minimize the inconvenience and eliminate the limitations caused by the limited linear range and interassay differences found in the calibration curves are outlined. In addition, the incorporation of artificial intelligence (AI) in SERS techniques to promote multivariate analysis and enhance diagnostic accuracy are discussed. The future prospects for SERS-based POC devices that include wearable POC SERS devices toward predictive, personalized medicine following the Fourth Industrial Revolution are proposed.

Nanoscale Technologies in Highly Sensitive Diagnosis of Cardiovascular Diseases

Cardiovascular diseases (CVD) are the leading cause of death and morbidity in the world and are a major contributor to healthcare costs. Although enormous progress has been made in diagnosing CVD, there is an urgent need for more efficient early detection and the development of novel diagnostic tools. Currently, CVD diagnosis relies primarily on clinical symptoms based on molecular imaging (MOI) or biomarkers associated with CVDs. However, sensitivity, specificity, and accuracy of the assay are still challenging for early-stage CVDs. Nanomaterial platform has been identified as a promising candidate for improving the practical usage of diagnostic tools because of their unique physicochemical properties. In this review article, we introduced cardiac biomarkers and imaging techniques that are currently used for CVD diagnosis. We presented the applications of various nanotechnologies on diagnosis within cardiac immunoassays (CIAs) and molecular imaging. We also summarized and compared different cardiac immunoassays based on their sensitivities and working ranges of biomarkers.