An ultrasensitive electrochemiluminescence immunosensor based on zeolitic imidazolate frameworks encapsulating spherical graphite crystals

Nanotechnology in coronary heart disease

Coronary heart disease (CHD) is one of the major causes of death and disability worldwide, especially in low- and middle-income countries and among older populations. Conventional diagnostic and therapeutic approaches have limitations such as low sensitivity, high cost and side effects. Nanotechnology offers promising alternative strategies for the diagnosis and treatment of CHD by exploiting the unique properties of nanomaterials. In this review, we use bibliometric analysis to identify research hotspots in the application of nanotechnology in CHD and provide a comprehensive overview of the current state of the art. Nanomaterials with enhanced imaging and biosensing capabilities can improve the early detection of CHD through advanced contrast agents and high-resolution imaging techniques. Moreover, nanomaterials can facilitate targeted drug delivery, tissue engineering and modulation of inflammation and oxidative stress, thus addressing multiple aspects of CHD pathophysiology. We discuss the application of nanotechnology in CHD diagnosis (imaging and sensors) and treatment (regulation of macrophages, cardiac repair, anti-oxidative stress), and provide insights into future research directions and clinical translation. This review serves as a valuable resource for researchers and clinicians seeking to harness the potential of nanotechnology in the management of CHD. STATEMENT OF SIGNIFICANCE: Coronary heart disease (CHD) is the one of leading cause of death and disability worldwide. Nanotechnology offers new strategies for diagnosing and treating CHD by exploiting the unique properties of nanomaterials. This review uses bibliometric analysis to uncover research trends in the use of nanotechnology for CHD. We discuss the potential of nanomaterials for early CHD detection through advanced imaging and biosensing, targeted drug delivery, tissue engineering, and modulation of inflammation and oxidative stress. We also offer insights into future research directions and potential clinical applications. This work aims to guide researchers and clinicians in leveraging nanotechnology to improve CHD patient outcomes and quality of life.

Highly sensitive competitive electrochemiluminescence immunosensor based on ABEI-H2O2 system with cobalt hydroxide nanosheets and bimetal PdAg as co-enhancer for detection of florfenicol

A competitive electrochemiluminescence immunoassay was established based on the isoluminol-H₂O₂ (ABEI-H₂O₂) system catalyzed by cobalt hydroxide (Co(OH)₂) to detect florfenicol residues in food. First , ultra-thin two-dimensional Co(OH)₂ nanosheets were used as the catalyst of ABEI-H₂O₂ system, and excellent catalytic effects were acquired by catalytic decomposition of hydrogen peroxide with cobalt ions. Then, bimetal PdAg (Pd/Ag) alloy nanoparticles were used as a bridge to connect ABEI and antibody due to their good biocompatibility; Pd/Ag alloy nanoparticles also had a catalytic effect to further amplify the ECL signal in the system due to the synergistic catalytic effect of the bimetal. A competitive immunoassay strategy was used to detect florfenicol, where the florfenicol in the sample will compete with the antibody for the limited binding sites on the coating antigen. The ECL immunosensor for florfenicol detection shows high sensitivity, with a linear range from 10^-4  to 10² ng mL^-1, and a detection limit of 3.1 × 10^-5 ng mL^-1, where the scan potential was varied from 0 to 0.6 V vs Ag/AgCl . This work was the first to use Co(OH)₂ nanosheets and bimetal PdAg catalytic signal amplification methods to design the sensor, which provides a novel, convenient and reliable strategy for ultra-sensitive detection of florfenicol, and other biological small molecules. A novel ECL immunosensor based on ABEI-H₂O₂₂.

Electrospun nanofibers modified with zeolitic imidazolate framework-8 for electrochemiluminescent determination of terbutaline

For the first time it is demonstrated that zeolitic imidazolate framework-8 electrospun nanofibers (ZIF-8 NF) could serve as electrochemiluminescence (ECL) accelerator for the facile detection of terbutaline residual. A novel ECL sensor for the determination of terbutaline was fabricated based on ZIF-8 NF. The ZIF-8 NF were successfully prepared according to electrospinning and in-situ growth method. First, chitosan was modified on the surface of the electrode, and then the ZIF-8 NF was modified onto the upper layer of the chitosan. Taking advantages of chitosan and ZIF-8 NF in conductivity and electrocatalysis, the modified electrode presents obvious ECL phenomenon in 0.2 M PBS solution (pH 10.0) containing 0.025 M luminol. After the addition of terbutaline, ECL intensity decreased significantly, and the decreasing value showed a linear relationship with the logarithm of terbutaline concentration. The linear range was from 2.0 × 10^-10 to 2.0 × 10^-5 M, and the detection limit was 1.41 × 10^-11 M (3σ/m). The method had high sensitivity, good stability, and good applicability to actual pork samples.

Nanoparticles-doped induced defective ZIF-8 as the novel cathodic luminophore for fabricating high-performance electrochemiluminescence aptasensor for detection of omethoate

Although the use of omethoate (OMT) for pests control is enormously economically beneficial for agricultural production, the high toxicity of OMT to nontarget organisms has resulted in the contamination of soil, river water, and food materials. Developing sensitive and convenient techniques to detect OMT residues is vital to society. Electrochemiluminescence (ECL) is a powerful analytical tool and has been widely applied in biosensors. To boost the co-reaction efficiency and ECL intensity, we introduced defective ZIF-8 as the novel cathodic luminophore. At the same time, defect generated by the doping of MoTe₂ nanoparticles into ZIF-8 could easily electrocatalytic reduce the co-reactor S₂O₈^2- to SO₄^•-. Hence, based on the catalysis of defective ZIF-8, the ECL intensity of MoTe₂/ZIF-8 nanocomposites is much higher than both ZIF-8 and MoTe₂ nanoparticles. By integration of as-prepared materials with specificity omethoate aptamer, the ECL sensor showed a broad linear range (10^-10 g L^-1 and 10^-5 g L^-1) and a comparatively low detection limit (3.3 × 10^-11 g L^-1). Besides, the ECL aptasensor appeared a good practical performance to detect potato and spinach extraction samples, which proposed a promising guideline for developing ECL aptasensors with high efficiency.

Fe3O4 NP@ZIF-8/MoS2 QD-based electrochemiluminescence with nanosurface energy transfer strategy for point-of-care determination of ATP

Herein, Fe₃O₄ NP@ZIF-8/MoS₂ QD-based electrochemiluminescence (ECL) biosensor with nanosurface energy transfer strategy was successfully developed for point-of-care determination of ATP. With the porous structure and poor electron transfer ability, Fe₃O₄ NP@ZIF-8 complex was first used as an excellent catalyst in ECL. The complex catalyzed the coreactant for more free radicals and hindered the quenching effect of Fe₃O₄ nanoparticles (NPs) on quantum dots (QDs). In ECL-nanosurface energy transfer (NSET) system, through the specific binding of complementary DNA linked to MoS₂ QDs (QDs-cDNA) and aptamer linked to Au NPs, interaction between the point dipole of MoS₂ QDs and the collective dipoles of Au NPs quenched ECL signal. When ATP was captured by aptamer, the ECL-NSET system was taken apart, which resulted in the recovery of ECL signal. Moreover, changes of the ECL imaging can be captured by a smartphone, which enabled point-of-care determination of ATP from 0.05 nmol L^-1 to 200 nmol L^-1 with LOD of 0.015 nmol L^-1. With superior specificity and stability, the sensing system showed significant potential about the application of catalysts coated with ZIF and NSET in point-of-care ECL determination.

Zeolitic imidazolate frameworks for use in electrochemical and optical chemical sensing and biosensing: a review

This review (with 145 refs.) summarizes the progress that has been made in the use of zeolitic imidazolate frameworks in chemical sensing and biosensing. Zeolitic imidazolate frameworks (ZIFs) are a type of porous material with zeolite topological structure that combine the advantages of zeolite and traditional metal-organic frameworks. Owing to the structural flexibility of ZIFs, their pore sizes and surface functionalization can be reasonably designed. Following an introduction into the field of metal-organic frameworks and the zeolitic imidazolate framework (ZIF) subclass, a first large section covers the various kinds and properties of ZIFs. The next large section covers electrochemical sensors and assays (with subsections on methods for gases, electrochemiluminescence, electrochemical biomolecules). This is followed by main sections on ZIF-based colorimetric and luminescent sensors, with subsections on sensors for metal ions and anions, for gases, and for organic biomolecules. The last section covers SERS-based assays. Several tables are presented that give an overview on the wealth of methods and materials. A concluding section summarizes the current status, addresses current challenges, and gives an outlook on potential future trends. Graphical abstract In recent years, ZIFs and their composites have been widely used as probes in chemical sensing, and these probes have shown great advantages over other materials. This review describes the current progress on ZIFs toward electrochemical, luminescence, colorimetric, and SERS-based sensing applications, highlighting the different strategies for designing ZIFs and their composites and potential challenges in this field.

Electrochemiluminescence Immunosensor Based on Au Nanocluster and Hybridization Chain Reaction Signal Amplification for Ultrasensitive Detection of Cardiac Troponin I

Measurement of cardiac troponin I in the blood is crucial for the early diagnosis of acute myocardial infarction. Herein, a novel and ultrasensitive electrochemiluminescence (ECL) immunosensor has been developed for determination of cardiac troponin I (cTnI) by using Au nanoclusters and hybridization chain reaction (HCR) signal amplification. In this ECL immunosensor, Au nanoclusters were dual-labeled at each end of hairpin DNA (H₁ and H₂) and acted as the luminophore. DNA initiator strands (T₁) and secondary antibody (Ab₂) were conjugated on Au nanoparticles (AuNPs) to obtain a smart probe (Ab₂-AuNP-T₁). In the presence of target cTnI, the sandwiched immunocomplex composed of cTnI, Ab₁, and Ab₂-AuNP-T₁ was formed. Then the initiator strands T₁ of Ab₂-AuNP-T₁ opened the hairpin DNA structures and triggered a cascade of hybridization events. Consequently, a large number of Au NCs were indirectly modified on the surface of the electrode, which could react with the coreactant (K₂S₂O₈) and emit a strong ECL signal. Under the optimal conditions, the immunosensor exhibited a wide detection range for cTnI from 5 fg/mL to 50 ng/mL and a low detection limit of 1.01 fg/mL (S/N = 3). Because of the excellent specificity, stability, and reproducibility of the proposed ECL-HCR sensor, it has a great application prospect for cTnI detection in clinical diagnosis.

Point-of-Care Compatibility of Ultra-Sensitive Detection Techniques for the Cardiac Biomarker Troponin I-Challenges and Potential Value

Cardiac biomarkers are frequently measured to provide guidance on the well-being of a patient in relation to cardiac health with many assays having been developed and widely utilised in clinical assessment. Effectively treating and managing cardiovascular disease (CVD) relies on swiftly responding to signs of cardiac symptoms, thus providing a basis for enhanced patient management and an overall better health outcome. Ultra-sensitive cardiac biomarker detection techniques play a pivotal role in improving the diagnostic capacity of an assay and thus enabling a better-informed decision. However, currently, the typical approach taken within healthcare depends on centralised laboratories performing analysis of cardiac biomarkers, thus restricting the roll-out of rapid diagnostics. Point-of-care testing (POCT) involves conducting the diagnostic test in the presence of the patient, with a short turnaround time, requiring small sample volumes without compromising the sensitivity of the assay. This technology is ideal for combatting CVD, thus the formulation of ultra-sensitive assays and the design of biosensors will be critically evaluated, focusing on the feasibility of these techniques for point-of-care (POC) integration. Moreover, there are several key factors, which in combination, contribute to the development of ultra-sensitive techniques, namely the incorporation of nanomaterials for sensitivity enhancement and manipulation of labelling methods. This review will explore the latest developments in cardiac biomarker detection, primarily focusing on the detection of cardiac troponin I (cTnI). Highly sensitive detection of cTnI is of paramount importance regarding the rapid rule-in/rule-out of acute myocardial infarction (AMI). Thus the challenges encountered during cTnI measurements are outlined in detail to assist in demonstrating the drawbacks of current commercial assays and the obstructions to standardisation. Furthermore, the added benefits of introducing multi-biomarker panels are reviewed, several key biomarkers are evaluated and the analytical benefits provided by multimarkers-based methods are highlighted.