Recent advancements of nanomodified electrodes - Towards point-of-care detection of cardiac biomarkers

Label-free electrochemical detection of glycated hemoglobin (HbA1c) and C-reactive protein (CRP) to predict the maturation of coronary heart disease due to diabetes

The pathophysiological link between diabetes and heightened propensity for the development of coronary heart disease (CHD) is well-established. Prevailing evidence confirms that small increases in low concentrations of high-sensitivity C reactive protein (hs-CRP) in the human body can determine the tendency of developing CHD. Additionally, glycated hemoglobin (HbA1c) is a well-recognized biomarker to evaluate diabetes progression. Given the positive correlation between diabetes and CHD, this research presents a notably unprecedented label-free electrochemical approach for the dual detection of %HbA1c regarding Total Hb and hs-CRP, facilitating early CHD prediction and cost-effective point-of-care diagnostics. Furthermore, a novel redox probe O-(4-Nitrophenylphosphoryl)choline (C11H17N2O6P) was used for the electrochemical detection of CRP, a method not documented in scientific literature before. The calibration curves demonstrate a limit of detection (LOD) of 5 mg/mL in PBS (pH 8) and 6 mg/mL in simulated blood (SB) for a linear range of 0-30 mg/mL of HbA1c. Conjointly, a LOD of 0.007 mg/mL and 0.008 mg/mL for measurement in PBS (pH 7.4) and SB are reported for a linear range of 0-0.05 mg/mL of CRP. The electrochemical systems presented could accurately quantify HbA1c and CRP in mixed samples, demonstrating reasonable specificity and practical applicability for complex biological samples.

Signal-enhanced electrochemical sensor employing MWCNTs/CMK-3/AuNPs and Au@Pd core-shell structure for sensitive determination of AFB1 in complex matrix

A sandwich electrochemical sensor was fabricated based on multi-walled carbon nanotubes/ordered mesoporous carbon/AuNP (MWCNTs/CMK-3/AuNP) nanocomposites and porous core-shell nanoparticles Au@PdNPs to achieve rapid and sensitive detection of AFB1 in complex matrices. MWCNTs/CMK-3/AuNP nanocomposite, which was prepared by self-assembly method, served as a substrate material to increase the aptamer loading and improve the conductivity and electrocatalytic activity of the electrode for the first signal amplification. Then, Au@PdNPs, which were synthesized by one-pot aqueous phase method, were applied as nanocarriers loaded with plenty of capture probe antibody (Ab) and signal molecule toluidine blue (Tb) to form the Au@PdNPs-Ab-Tb bioconjugates for secondary signal amplification. The sensing system could still significantly improve the signal output intensity even in the presence of ultra-low concentration target compound due to the dual signal amplification of MWCNTs/CMK-3/AuNP nanocomposites and Au@PdNPs-Ab-Tb. The method exhibited high selectivity, low detection limit (9.13 fg/mL), and strong stability to differentiate AFB1 from other mycotoxins. Furthermore, the sensor has been successfully applied to the quantitative determination of AFB1 in corn, malt, and six herbs, which has potential applications in food safety, quality control, and environmental monitoring.

Advancements in electrochemical biosensing of cardiovascular disease biomarkers

Cardiovascular diseases (CVDs) stand as a predominant global health concern, introducing vast socioeconomic challenges. In addressing this pressing dilemma, enhanced diagnostic modalities have become paramount, positioning electrochemical biosensing as an instrumental innovation. This comprehensive review navigates the multifaceted terrain of CVDs, elucidating their defining characteristics, clinical manifestations, therapeutic avenues, and intrinsic risk factors. Notable emphasis is placed on pivotal diagnostic tools, spotlighting cardiac biomarkers distinguished by their unmatched clinical precision in terms of relevance, sensitivity, and specificity. Highlighting the broader repercussions of CVDs, there emerges an accentuated need for refined diagnostic strategies. Such an exploration segues into a profound analysis of electrochemical biosensing, encapsulating its foundational principles, diverse classifications, and integral components, notably recognition molecules and transducers. Contemporary advancements in biosensing technologies are brought to the fore, emphasizing pioneering electrode architectures, cutting-edge signal amplification processes, and the synergistic integration of biosensors with microfluidic platforms. At the core of this discourse is the demonstrated proficiency of biosensors in detecting cardiovascular anomalies, underpinned by empirical case studies, systematic evaluations, and clinical insights. As the narrative unfolds, it addresses an array of inherent challenges, spanning intricate technicalities, real-world applicability constraints, and regulatory considerations, finally, by casting an anticipatory gaze upon the future of electrochemical biosensing, heralding a new era of diagnostic tools primed to revolutionize cardiovascular healthcare.

Prunella vulgaris-phytosynthesized platinum nanoparticles: Insights into nanozymatic activity for H2O2 and glutamate detection and antioxidant capacity

Artificial nanozymes (enzyme-mimics), specifically metallic nanomaterials, have garnered significant attention recently due to their reduced preparation cost and enhanced stability in a wide range of environments. The present investigation highlights, for the first time, a straightforward green synthesis of biogenic platinum nanoparticles (PtNPs) from a natural resource, namely Prunella vulgaris (Pr). To demonstrate the effectiveness of the phytochemical extract as an effective reducing agent, the PtNPs were characterized by various techniques such as UV-vis spectroscopy, High-resolution Transmission electron microscopy (HR-TEM), zeta-potential analysis, Fourier-transform infrared spectroscopy (FTIR), and Energy dispersive spectroscopy (EDS). The formation of PtNPs with narrow size distribution was verified. Surface decoration of PtNPs was demonstrated with multitudinous functional groups springing from the herbal extract. To demonstrate their use as viable nanozymes, the peroxidase-like activity of Pr/PtNPs was evaluated through a colorimetric assay. Highly sensitive visual detection of H2O2 with discrete linear ranges and a low detection limit of 3.43 μM was demonstrated. Additionally, peroxidase-like catalytic activity was leveraged to develop a colorimetric platform to quantify glutamate biomarker levels with a high degree of selectivity, the limit of detection (LOD) being 7.00 μM. The 2,2-Diphenyl-1-picrylhydrazyl (DPPH) test was used to explore the scavenging nature of the PtNPs via the degradation of DPPH. Overall, the colorimetric assay developed using the Pr/PtNP nanozymes in this work could be used in a broad spectrum of applications, ranging from biomedicine and food science to environmental monitoring.

Enhanced Nanozymatic Activity on Rough Surfaces for H2O2 and Tetracycline Detection

The needless use of tetracyclines (TCs) in foodstuffs is a huge health concern in low- and middle-income and Arab countries. Herein, a sensitive and faster monitoring system for H2O2 and TCs is proposed, utilizing the large surface-to-volume ratio of a non-spherical gold nanoparticle/black phosphorus nanocomposite (BP-nsAu NPs) for the first time. BP-nsAu NPs were synthesized through a single-step method that presented nanozymatic activity through 3,3',5,5'-Tetramethylbenzidine (TMB) oxidation while H2O2 was present and obeyed the Michaelis-Menten equation. The nanozymatic activity of the BP-nsAu NPs was enhanced 12-fold and their detection time was decreased 83-fold compared to conventional nanozymatic reactions. The proposed method enabled us to quantify H2O2 with a limit of detection (LOD) value of 60 nM. Moreover, target-specific aptamer-conjugated BP-nsAu NPs helped us detect TCs with an LOD value of 90 nM. The present strategy provides a proficient route for low-level TC monitoring in real samples.

Advanced Nanomaterial-Based Biosensors for N-Terminal Pro-Brain Natriuretic Peptide Biomarker Detection: Progress and Future Challenges in Cardiovascular Disease Diagnostics

Cardiovascular diseases (CVDs) represent a significant challenge in global health, demanding advancements in diagnostic modalities. This review delineates the progressive and restrictive facets of nanomaterial-based biosensors in the context of detecting N-terminal pro-B-type natriuretic peptide (NT-proBNP), an indispensable biomarker for CVD prognosis. It scrutinizes the escalation in diagnostic sensitivity and specificity attributable to the incorporation of novel nanomaterials such as graphene derivatives, quantum dots, and metallic nanoparticles, and how these enhancements contribute to reducing detection thresholds and augmenting diagnostic fidelity in heart failure (HF). Despite these technological strides, the review articulates pivotal challenges impeding the clinical translation of these biosensors, including the attainment of clinical-grade sensitivity, the substantial costs associated with synthesizing and functionalizing nanomaterials, and their pragmatic deployment across varied healthcare settings. The necessity for intensified research into the synthesis and functionalization of nanomaterials, strategies to economize production, and amelioration of biosensor durability and ease of use is accentuated. Regulatory hurdles in clinical integration are also contemplated. In summation, the review accentuates the transformative potential of nanomaterial-based biosensors in HF diagnostics and emphasizes critical avenues of research requisite to surmount current impediments and harness the full spectrum of these avant-garde diagnostic instruments.