Search

Root rot is a highly infectious disease in traditional Chinese medicine (TCM) that spreads quickly and significantly affects the yield and quality of TCM. Therefore, there is an urgent need for accurate and convenient early warning technology to guide root rot control. The root rot of TCM is mainly caused by Fusarium fungi infecting plants. After plants have been infected with fungi, zearalenone (ZEN), fumonisin (FB), fusarium acid (FA), and other compounds will produce duo to Fusarium infects plants to promote metabolism. And the trace expression of these compounds in plants is used as root rot early warning markers (RREWM). Herein, an electrochemical immunosensor was developed for the rapid, convenient, and sensitive detection of zearalenone (ZEN), an early warning marker for Radix isatidis root rot. The immunosensor utilizes Fe3O4@g-C3N4 composite ITO electrode. Initially, the ITO conductive films were modified with Fe3O4@g-C3N4 and gold nanoparticles (AuNPs) through droplet coating and chemical deposition, respectively. Subsequently, the AuNPs were conjugated with zearalenone antibody (ZEN-Ab) to generate high affinity sulfhydryl-bound recognition elements. Under the optimized condition, the sensor demonstrates a linear wide range of 10.00 pg mL−1 to 1.20 × 104 pg mL−1 with a LOD of 3.86 pg mL−1. Additionally, the sensor showed good reproducibility and stability. This study exhibits a convenient, accurate, and low-cost method for detecting early warning markers of root rot in TCM cultivation, which was expected to provide a reliable warning technology for the early warning and prevention of diseases in the planting process of TCM. [ABSTRACT FROM AUTHOR]

A novel electrochemical immunosensor was developed for highly sensitive detection of brain-derived neurotrophic factor (BDNF), a well-known depression marker. The immunosensor was fabricated by modifying indium tin oxide-coated polyethylene terephthalate (ITO-PET) with N-doped graphene-polyaniline (NG-PANI) and gold nanoparticles (AuNPs) to enhance the conductivity and protein loading capacity. Subsequently, BDNF was immobilized onto the electrode surface via gold-sulfur bonds, followed by the attachment of biotinylated antibody (Biotin-Ab) and horseradish peroxidase-avidin (HRP-Avidin) to create the final immunosensor (HRP-Avidin–Biotin-Ab-BDNF-AuNPs/NG-PANI/ITO-PET). The proposed immunosensor exhibited a linear range of determination (0.781–400 pg/mL) with a low limit of detection (LOD) of 0.261 pg/mL (S/N = 3) and excellent reproducibility (RSD = 1.4%) and stability (92.7%, RSD = 3.1%). Additionally, the immunosensor demonstrated good anti-interference performance and good recovery (98.1–107%). To evaluate the practical utility of the immunosensor, BDNF levels were quantified in the serum of mice with depression induced by chronic unpredictable mild stress (CUMS). The results indicated that the serum BDNF levels were significantly decreased in the depression model group compared with the control group, highlighting the potential of this immunosensor for clinical detection of BDNF in depression diagnosis and treatment. [ABSTRACT FROM AUTHOR]

The accurate and sensitive analysis of rheumatoid arthritis(RA) trace biomarkers is essential for early warning and diagnosis of RA, while anti‐cyclic citrullinated peptide antibody (anti‐CCP‐ab) is a specific one. In this study, a simple label‐free electrochemical immunosensor for the detection of anti‐CCP‐ab was constructed with nitrogen‐doped graphene (N−G) and gold nanoparticles (AuNPs). The proposed non‐enzyme immunosensor had exhibited high specificity, selectivity, and stability in the linear calibration curve range from 0.125∼2000 pg mL‐1 and has been successfully used in the detection of anti‐CCP‐ab in human serum, providing a new idea for the early diagnosis of RA. [ABSTRACT FROM AUTHOR]

A sensitively competitive electrochemical immunosensor for the detection of cortisol was successfully developed based on gold nanoparticles and magnetic functionalized reduced graphene oxide (AuNPs/MrGO). In order to construct the base of the immunosensor, the MrGO was initially fabricated by chemical cross-linking and used to modify the nafion pretreated glassy carbon electrode. Subsequently, the surface of electrode was modified by AuNPs via electrochemical deposition. A variety of cortisol (Cor) can be firmly loaded in the AuNPs/MrGO with large specific surface area and good bioactivity to construct the basic electrode (Cor/AuNPs/MrGO/Nafion@GCE), which was characterized by the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), respectively. Due to the cortisol on the surface of basic electrode and samples can competitively combine with the cortisol antibody labelled by horseradish peroxidase (HRP-Strept-Biotin-Ab). Finally, the detection signal of electrochemical immunosensor (HRP-Strept-Biotin-Ab-Cor/AuNPs/MrGO/Nafion@GCE) in the test liquid had negative correlations with the concentration of cortisol in samples. The AuNPs/MrGO with excellent electrical conductivity being applied, the electrochemical response of the immunosensor was immensely amplified. The immunosensor displayed excellent analytical performance for the detection of cortisol range from 0.1 to 1000 ng/mL with a detection limit of 0.05 ng/mL at 3σ. Moreover, compared the developed immunoassay with commercially available enzyme linked immunosorbent assay, the proposed method showed good precision, acceptable stability and reproducibility, indicating the immunosensor could be used for the sensitive, efficient and real-time detection of cortisol in real samples. Therefore, the present strategy provides a novel and convenient method for clinical determination of cortisol. [ABSTRACT FROM AUTHOR]

Developing wearable flexible biosensors with excellent electrical conductivity and outstanding flexibility simultaneously for disease diagnosis and health monitoring is a current hot topic in the field of sensor research. In this study, nitrogen-doped graphene (N-Gr) and gold nanoparticles (AuNPs) were successively deposited onto ITO-PET flexible conductive films by chemical deposition, and then a flexible electrochemical immunosensor with high sensitivity and selectivity was constructed for detecting depression markers by exploiting the high affinity between AuNPs and the sulfhydryl groups of depression marker (DM) antibody. Due to the composite of N-Gr, AuNPs and ITO-PET, the prepared flexible sensor can maintain a relatively stable electrical signal response regardless of the deformation such as spiral, rolling, and bending, without shedding or fracture of the N-Gr and AuNPs, and can also significantly amplify the electrochemical response signal of the immunosensor. Under optimized experimental conditions, the fabricated immunosensor showed good linearity over a wide range of 0.023–300.00 ng/mL with a low detection limit of 0.010 ng/mL (3σ, n = 5), when it was used for the determination of depression markers-human Apo-A4 in 100% whole serum samples. The flexibility of the constructed immunosensor and the stability and sensitivity of biomolecular analysis are expected to be further made into implantable depression marker in-situ monitoring probe with the help of micro-machining technology, which will develop a promising method for objective, efficient and accurate clinical diagnosis of depression. Schematic representation of constructing AuNPs@N-Gr@ITO-PET-based electrochemical immunosensor for determination of apolipoprotein A4 (Apo-A4). [Display omitted] • A highly sensitive and selective flexible immunosensor for determination of human apolipoprotein A4 (Apo-A4) has been fabricated. • The prepared AuNPs@N-Gr with large specific surface area, excellent electrical conductivity and outstanding flexibility can amplify the signal of immunosensor. • The proposed immunosensor can be used to sensitively and efficiently analyze apolipoprotein A4 (Apo-A4) in serum samples. • This method would provide a promising potential in early clinical screening and diagnosis of depression. [ABSTRACT FROM AUTHOR]

Leptin is a vital biomarker of non-alcoholic fatty liver (NAFLD), and its evaluation of the concentration level in vivo is of great significance to NAFLD diagnosis. Therefore, it is pressing to develop a method for rapid and sensitive detection of leptin. This paper describes an environmentally friendly and label-free immunosensor based on porous graphene functionalized black phosphorus (PG-BP) composite to detect of leptin. The PG-BP was synthesized via strong coherent coupling between porous graphene (PG) surface plasmons and anisotropic black phosphorus (BP) localized surface plasmons, which made the electrochemical performance of PG and BP synergistic as well as increased the stability and conductive capability of BP material. The PG-BP modified electrodes was further prepared by gold nanoparticles, cysteamine, and glutaraldehyde in turn. Due to the cross-linking effect of glutaraldehyde, anti-leptin can be firmly fixed. These properties of the platform improved the conductive capability of the immunosensor and enhanced the load capacity of the proteins, thereby, the sensitivity of the immunosensor was significantly increased. Under the optimal conditions, the proposed immunosensor exhibited a wide linear range of 0.150–2500 pg/mL with a low detection limit of 0.036 pg/mL. The leptin immunosensor displayed excellent selectivity and anti-interference ability, which could be used for early screening and diagnosis of clinical NALFD. • A BSA/anti-leptin/Glu/Cys/AuNPs/PG-BP/GCE immunosensor was successfully fabricated. • The proposed immunosensor was successfully used for the detection of leptin with a wide range of detection and low detection limits. • The immunosensor can be used for the sensitive, efficient and real-time analysis of leptin in real samples. • The immunosensor is expected to provide a reliable, real-time and convenient method for clinical trials of NAFLD markers. [ABSTRACT FROM AUTHOR]