Multiplexed sensing techniques for cardiovascular disease biomarkers - A review

A plug-and-play, easy-to-manufacture fluidic accessory to significantly enhance the sensitivity of electrochemical immunoassays

Earlier access to patients' biomarker status could transform disease management. However, gold-standard techniques such as enzyme-linked immunosorbent assays (ELISAs) are typically not deployed at the point-of-care due to their cumbersome instrumentation and complexity. Electrochemical immunosensors can be disruptive in this sector with their small size and lower cost but, without further modifications, the performance of these sensors in complex media (e.g., blood) has been limited. This paper presents a low-cost fluidic accessory fabricated using widely accessible materials and processes for boosting sensor sensitivity through confinement of the detection media next to the electrode surface. Liquid confinement first highlighted a spontaneous reaction between the pseudoreference electrode and ELISA detection substrate 3,3',5,5'-tetramethylbenzidine (TMB) that decreases the amount of oxTMB available for detection. Different strategies are investigated to limit this and maximize reliability. Next, flow cell integration during the signal amplification step of sensor preparation was shown to substantially enhance the detection of cytokine interleukin-6 (IL-6) with the best sensitivity boost recorded for fresh human plasma (x7 increase compared to x5.8 in purified serum and x5.5 in PBS). The flow cell requires no specialized equipment and can be seamlessly integrated with commercial sensors, making an ideal companion for electrochemical signal enhancement.

Bias-Free Cardiac Monitoring Capsule

Cardiovascular disease (CVD) remains the leading cause of death worldwide. Patients often fail to recognize the early signs of CVDs, which display irregularities in cardiac contractility and may ultimately lead to heart failure. Therefore, continuously monitoring the abnormal changes in cardiac contractility may represent a novel approach to long-term CVD surveillance. Here, a zero-power consumption and implantable bias-free cardiac monitoring capsule (BCMC) is introduced based on the triboelectric effect for cardiac contractility monitoring in situ. The output performance of BCMC is improved over 10 times with nanoparticle self-adsorption method. This device can be implanted into the right ventricle of swine using catheter intervention to detect the change of cardiac contractility and the corresponding CVDs. The physiological signals can be wirelessly transmitted to a mobile terminal for analysis through the acquisition and transmission module. This work contributes to a new option for precise monitoring and early diagnosis of CVDs.

Amyloid detection in neurodegenerative diseases using MOFs

Neurodegenerative diseases (amyloid diseases such as Alzheimer's and Parkinson's), stemming from protein misfolding and aggregation, encompass a spectrum of disorders with severe systemic implications. Timely detection is pivotal in managing these diseases owing to their significant impact on organ function and high mortality rates. The diverse array of amyloid disorders, spanning localized and systemic manifestations, underscores the complexity of these conditions and highlights the need for advanced detection methods. Traditional approaches have focused on identifying biomarkers using imaging techniques (PET and MRI) or invasive procedures. However, recent efforts have focused on the use of metal-organic frameworks (MOFs), a versatile class of materials known for their unique properties, in revolutionizing amyloid disease detection. The high porosity, customizable structures, and biocompatibility of MOFs enable their integration with biomolecules, laying the groundwork for highly sensitive and specific biosensors. These sensors have been employed using electrochemical and photophysical techniques that target amyloid species under neurodegenerative conditions. The adaptability of MOFs allows for the precise detection and quantification of amyloid proteins, offering potential advancements in early diagnosis and disease management. This review article delves into how MOFs contribute to detecting amyloid diseases by categorizing their uses based on different sensing methods, such as electrochemical (EC), electrochemiluminescence (ECL), fluorescence, Förster resonance energy transfer (FRET), up-conversion luminescence resonance energy transfer (ULRET), and photoelectrochemical (PEC) sensing. The drawbacks of MOF biosensors and the challenges encountered in the field are also briefly explored from our perspective.

One-Stop Plasmonic Nanocube-Excited SERS Immunoassay Platform of Multiple Cardiac Biomarkers for Rapid Screening and Progressive Tracing of Acute Myocardial Infarction

Rapid and precise acute myocardial infarction (AMI) diagnosis is essential for preventing patient death. In addition, the complementary roles of creatine kinase muscle brain (CK-MB) and cardiac troponin I (cTnI) cardiac biomarkers in the early and late stages of AMI demand their simultaneous detection, which is difficult to implement using conventional fluorescence and electrochemical technologies. Here, a nanotechnology-based one-stop immuno-surface-enhanced Raman scattering (SERS) detection platform is reported for multiple cardiac indicators for the rapid screening and progressive tracing of AMI events. Optimal SERS is achieved using optical property-based, excitation wavelength-optimized, and high-yield anisotropic plasmonic gold nanocubes. Optimal immunoassay reaction efficiencies are achieved by increasing immobilized antibodies. Multiple simultaneous detection strategies are implemented by incorporating two different Raman reports with narrow wavenumbers corresponding to two indicators and by establishing a computational SERS mapping process to accurately detect their concentrations, irrespective of multiple enzymes in the human serum. The SERS platform precisely estimated AMI onset and progressive timing in human serum and made rapid AMI identification feasible using a portable Raman spectrometer. This integrated platform is hypothesized to significantly contribute to emergency medicine and forensic science by providing timely treatment and observation.

A One Step Strategy Based on Hollow Gold Nanoparticles to Detect C-Reactive Protein with High Sensitivity (Hs-CRP) in Serum for Monitoring Cardiovascular Disease

Purpose

Rapid detection and diagnosis of diseases facilitate timely and effective treatment of cardiovascular diseases (CVD). The establishment of a one-step rapid detection method provides a new method for the initial screening and disease risk assessment of patients with cardiovascular diseases in primary medical units.

Methods

Hollow gold nanoparticles (HGNPs) were synthesized using a cobalt template method followed by use as signal amplification probes for ultra-sensitive quantitative detection of serum C-reactive protein (CRP). To induce the localized surface plasmon resonance (LSPR) and improve protein labeling efficiency, we developed a sensitive detection mode by coating polyvinylpyrrolidone (PVP-K30) on the HGNPs, resulting in a significant improvement in detection performance.

Results

Compared to traditional colloidal GNP-based LFTA, PVP-coated HGNPs exhibit a lower visual detection limit of 1 ng/mL, which a 25-fold decrement compare to using GNPs as the antibody-labeled probe, and the detection limit could be reduced to 0.14 ng/mL under the quantitative instrument.

Conclusion

The one-step method based on HGNP immunochromatographic strips modified with PVP established in this study can be used for the detection of CRP and hs-CRP in biological samples. The performance of the immunochromatographic technique designed in this study was evaluated from the perspective of synthetic markers, and the application conditions of this strip were screened, verifying its high specificity, indicating that it has high sensitivity and strong detection limit compared to colloidal gold. The sensitivity of the hollow gold immunochromatographic test strip in this article has been increased by about 25 times, providing a new method for rapid detection of CVD in clinical diagnosis.

Chemical-Chemical Redox Cycle Signal Amplification Strategy Combined with Dual Ratiometric Immunoassay for Surface-Enhanced Raman Spectroscopic Detection of Cardiac Troponin I

Improving the sensitivity and reproducibility of surface-enhanced Raman spectroscopy (SERS) methods for the detection of bioactive molecules is crucial in biological process research and clinical diagnosis. Herein, we designed a novel SERS platform for cardiac troponin I (cTnI) detection by a chemical-chemical redox cycle signal amplification strategy combined with a dual ratiometric immunoassay. First, ascorbic acid (AA) was generated by enzyme-assisted immunoreaction with a cTnI-anchored sandwich structure. Then, oxidized 4-mercaptophenol (ox4-MP) was reacted with AA to produce 4-mercaptophenol (4-MP). Quantitative analysis of cTnI was realized by a Raman signal switch between ox4-MP and 4-MP. Specifically, AA could be regenerated by reductant (tris(2-carboxyethyl) phosphine, TCEP), which in turn produced more signal indicator 4-MP, causing significant signal amplification for cTnI analysis by SERS immunosensing. Moreover, a dual ratiometric-type SERS method was established with the intensity ratio I1077/I822 and I633/I822, which improved the reproducibility of the cTnI assay. The excellent performance of the chemical-chemical redox cycle strategy and ratio-type SERS assay endows the method with high sensitivity and reproducibility. The linear ranges of cTnI were 0.001 to 50.0 ng mL-1 with detection limits of 0.33 pg mL-1 (upon I1077/I822) and 0.31 pg mL-1 (upon I635/I822), respectively. The amount of cTnI in human serum samples yielded recoveries from 89.0 to 114%. This SERS method has remarkable analytical performance, providing an effective approach for the early diagnosis of cardiovascular diseases, and has great latent capacity in the sensitive detection of bioactive molecules.

Low-noise fluorescent detection of cardiac troponin I in human serum based on surface acoustic wave separation

Acute myocardial infarction (AMI) is a life-threatening disease when sudden blockage of coronary artery occurs. As the most specific biomarker, cardiac troponin I (cTnI) is usually checked separately to diagnose or eliminate AMI, and achieving the accurate detection of cTnI is of great significance to patients' life and health. Compared with other methods, fluorescent detection has the advantages of simple operation, high sensitivity and wide applicability. However, due to the strong fluorescence interference of biological molecules in body fluids, it is often difficult to obtain high sensitivity. In order to solve this problem, in this study, surface acoustic wave separation is designed to purify the target to achieve more sensitive detection performance of fluorescent detection. Specifically, the interference of background noise is almost completely removed on a microfluidic chip by isolating microbeads through acoustic radiation force, on which the biomarkers are captured by the immobilized detection probe. And then, the concentration of cTnI in human serum is detected by the fluorescence intensity change of the isolated functionalized beads. By this way, the detection limit of our biosensor calculated by 3σ/K method is 44 pg/mL and 0.34 ng/mL in PBS buffer and human serum respectively. Finally, the reliability of this method has been validated by comparison with clinical tests from the nephelometric analyzer in hospital.

Thin, soft, wearable system for continuous wireless monitoring of artery blood pressure

Continuous monitoring of arterial blood pressure (BP) outside of a clinical setting is crucial for preventing and diagnosing hypertension related diseases. However, current continuous BP monitoring instruments suffer from either bulky systems or poor user-device interfacial performance, hampering their applications in continuous BP monitoring. Here, we report a thin, soft, miniaturized system (TSMS) that combines a conformal piezoelectric sensor array, an active pressure adaptation unit, a signal processing module, and an advanced machine learning method, to allow real wearable, continuous wireless monitoring of ambulatory artery BP. By optimizing the materials selection, control/sampling strategy, and system integration, the TSMS exhibits improved interfacial performance while maintaining Grade A level measurement accuracy. Initial trials on 87 volunteers and clinical tracking of two hypertension individuals prove the capability of the TSMS as a reliable BP measurement product, and its feasibility and practical usability in precise BP control and personalized diagnosis schemes development.

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.

One-step impedimetric NT-proBNP aptasensor targeting cardiac insufficiency in artificial saliva

Currently, sensitive and accurate approaches for diagnosis, rapid assessment, and cardiac biomarker monitoring in patients with heart failure are needed. In this context, the advantages of aptamers over traditional antibodies have been employed to fabricate a single-step impedimetric N-terminal pro b-type natriuretic peptide (NT-proBNP)-modified gold microelectrode array. The development of an electrochemical aptasensing platform was based on the coimmobilization of alkanethiol self-assembled monolayers and amine-terminated aptamer that specifically recognized cardiac NT-proBNP protein resulting in charge electron transfer. Electroimpedimetric signals of the sensor were observed to be linear to the NT-proBNP concentrations in the range of 5.0 × 10^-3 to 1.0 pg mL^-1 (R² = 0.9624), while achieving a low detection limit of 5.0 × 10^-3 pg mL^-1. Clinically relevant detection levels for NT-proBNP were achieved in a simple, rapid, and label-free measurement using artificial saliva, which was highlighted to be specific, regenerative, and selective over potential interferers occurring during the processes of cardiac insufficiency, Therefore, the novel NT-proBNP aptasensor is a promising point-of-care tool exhibiting safe, non-invasive, affordable, and non-prescription home use accessible to overcome the limitations associated with conventional ELISA and previous aptasensing.

Simultaneous Electrochemical Detection of LDL and MDA-LDL Using Antibody-Ferrocene or Anthraquinone Conjugates Coated Magnetic Beads

The simultaneous detection of atherosclerotic cardiovascular disease (ACSVD) biomarkers was recently of great scientific interest. In this work, magnetic beads-based immunosensors for the simultaneous detection of low density lipoprotein (LDL) and malondialdehyde-modified low density lipoprotein (MDA-LDL) were presented. The approach proposed was based on the formation of two types of specific immunoconjugates consisting of monoclonal antibodies: anti-LDL or anti-MDA-LDL, together with redox active molecules: ferrocene and anthraquinone, respectively, coated on magnetic beads (MBs). The decrease in redox agent current in the concentration range: 0.001-1.0 ng/mL for LDL and 0.01-10.0 ng/mL for MDA-LDL, registered by square wave voltammetry (SWV), was observed upon the creation of complex between LDL or MDA-LDL and appropriate immunoconjugates. The detection limits of 0.2 ng/mL for LDL and 0.1 ng/mL for MDA-LDL were estimated. Moreover, the results of selectivity against the possible interferents were good, as human serum albumin (HSA) and high density lipoprotein (HDL), stability and recovery studies demonstrated the potential of platform proposed for early prognosis and diagnosis of ASCVD.

Multiplex Detection of Infectious Diseases on Microfluidic Platforms

Infectious diseases contribute significantly to the global disease burden. Sensitive and accurate screening methods are some of the most effective means of identifying sources of infection and controlling infectivity. Conventional detecting strategies such as quantitative polymerase chain reaction (qPCR), DNA sequencing, and mass spectrometry typically require bulky equipment and well-trained personnel. Therefore, mass screening of a large population using conventional strategies during pandemic periods often requires additional manpower, resources, and time, which cannot be guaranteed in resource-limited settings. Recently, emerging microfluidic technologies have shown the potential to replace conventional methods in performing point-of-care detection because they are automated, miniaturized, and integrated. By exploiting the spatial separation of detection sites, microfluidic platforms can enable the multiplex detection of infectious diseases to reduce the possibility of misdiagnosis and incomplete diagnosis of infectious diseases with similar symptoms. This review presents the recent advances in microfluidic platforms used for multiplex detection of infectious diseases, including microfluidic immunosensors and microfluidic nucleic acid sensors. As representative microfluidic platforms, lateral flow immunoassay (LFIA) platforms, polymer-based chips, paper-based devices, and droplet-based devices will be discussed in detail. In addition, the current challenges, commercialization, and prospects are proposed to promote the application of microfluidic platforms in infectious disease detection.

Challenges and perspectives of multi-virus biosensing techniques: A review

In the context of globalization, individuals have an increased chance of being infected by multiple viruses simultaneously, thereby highlighting the importance of developing multiplexed devices. In addition to sufficient sensitivity and rapid response, multi-virus sensing techniques are expected to offer additional advantages including high throughput, one-time sampling for parallel analysis, and full automation with data visualization. In this paper, we review the optical, electrochemical, and mechanical platforms that enable multi-virus biosensing. The working mechanisms of each platform, including the detection principle, transducer configuration, bio-interface design, and detected signals, are reviewed. The advantages and limitations, as well as the challenges in implementing various detection strategies in real-life scenarios, were evaluated. Future perspectives on multiplexed biosensing techniques are critically discussed. Earlier access to multi-virus biosensors will efficiently serve for immediate pandemic control, such as in emerging SARS-CoV-2 and monkeypox cases.

Lateral flow assays for detection of disease biomarkers

Early diagnosis saves lives in many diseases. In this sense, monitoring of biomarkers is crucial for the diagnosis of diseases. Lateral flow assays (LFAs) have attracted great attention among paper-based point-of-care testing (POCT) due to their low cost, user-friendliness, and time-saving advantages. Developments in the field of health have led to an increase of interest in these rapid tests. LFAs are used in the diagnosis and monitoring of many diseases, thanks to biomarkers that can be observed in body fluids. This review covers the recent advances dealing with the design and strategies for the development of LFA for the detection of biomarkers used in clinical applications in the last 5 years. We focus on various strategies such as choosing the nanoparticle type, single or multiple test approaches, and equipment for signal transducing for the detection of the most common biomarkers in different diseases such as cancer, cardiovascular, infectious, and others including Parkinson's and Alzheimer's diseases. We expect that this study will contribute to the different approaches in LFA and pave the way for other clinical applications.

Sonochemical construction of hierarchical strontium doped lanthanum trisulfide electrocatalyst: An efficient electrode for highly sensitive detection of ecological pollutant in food and water

Herbicides are used constantly in agriculture to enhance productivity across the globe. This herbicide monitoring requires utmost importance since its high dose leads to ecological imbalance and a negative impact on the environment. Moreover, a quantification of toxic herbicide is one of the important problems in the food analysis. In this work, deals with the development of a simple, and facile one-pot sonochemical synthesis of strontium doped La₂S₃ (Sr@La₂S₃). Morphological and structural characterization confirms the doping of Sr@La₂S₃ to generate a hierarchical layered structure. The electrochemical performance of modified with rotating disk electrode (RDE) using Sr@La₂S₃ composite is high, compared to La₂S₃ and bare electrodes towards the quantitative detection of mesotrione (MTO) in phosphate buffer. Sr@La₂S₃/RDE showed good sensitivity for MTO detection and it exhibit a range of 0.01-307.01 μM and limit of detection of 2.4 nM. Besides, the selectivity of fabricated electrode is high as it can electrochemically reduce MTO particularly, even in the presence of other chemicals, biological molecules and inorganic ions. The repeatability of MTO detection is high even after 30 days with a lower RSD values. Hence, simple fabrication of Sr@La₂S₃/RDE could be a novel electrode for the sensitive, selective, and reproducible determination of herbicides in real-time applications.

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.

Graphitic Carbon Nitride and IGZO Bio-FET for Rapid Diagnosis of Myocardial Infarction

Acute myocardial infarction (AMI), commonly known as a heart attack, is a life-threatening condition that causes millions of deaths every year. In this study, a transistor-based biosensor is developed for rapid and sensitive detection of cardiac troponin-I (cTnI), a diagnostic biomarker of AMI. A biosensing technique based on a field effect transistor (FET), which uses indium gallium zinc oxide (IGZO) as an excellent semiconducting channel, is integrated with nanosheet materials to detect cTnI. Porous carbon nitride (PCN) decorated with gold nanoparticles (Au NPs) is used as a bridge between the solid-state device and the biorecognition element. We demonstrate that this biosensor is highly sensitive and has an experimental limit of detection of 0.0066 ng/mL and a dynamic range of 0.01 ng/mL-1000 ng/mL. This is the first report of a semiconducting metal oxide FET cardiac biomarker sensor combined with PCN for the detection of cTnI. The reported compact microsystem paves the way for rapid and inexpensive detection of cardiac biomarkers.

Ruthenium and Nickel Molybdate-Decorated 2D Porous Graphitic Carbon Nitrides for Highly Sensitive Cardiac Troponin Biosensor

Two-dimensional (2D) layered materials functionalized with monometallic or bimetallic dopants are excellent materials to fabricate clinically useful biosensors. Herein, we report the synthesis of ruthenium nanoparticles (RuNPs) and nickel molybdate nanorods (NiMoO₄ NRs) functionalized porous graphitic carbon nitrides (PCN) for the fabrication of sensitive and selective biosensors for cardiac troponin I (cTn-I). A wet chemical synthesis route was designed to synthesize PCN-RuNPs and PCN-NiMoO₄ NRs. Morphological, elemental, spectroscopic, and electrochemical investigations confirmed the successful formation of these materials. PCN-RuNPs and PCN-NiMoO₄ NRs interfaces showed significantly enhanced electrochemically active surface areas, abundant sites for immobilizing bioreceptors, porosity, and excellent aptamer capturing capacity. Both PCN-RuNPs and PCN-NiMoO₄ NRs materials were used to develop cTn-I sensitive biosensors, which showed a working range of 0.1–10,000 ng/mL and LODs of 70.0 pg/mL and 50.0 pg/mL, respectively. In addition, the biosensors were highly selective and practically applicable. The functionalized 2D PCN materials are thus potential candidates to develop biosensors for detecting acute myocardial infractions.