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Rapid, sensitive, and reliable detection of high mobility group box 1 (HMGB1) is essential for medical and diagnostic applications due to its important role as a biomarker of chronic inflammation. Here, we report a facile method for the detection of HMGB1 using carboxymethyl dextran (CM-dextran) as a bridge molecule modified on the surface of gold nanoparticles combined with a fiber optic localized surface plasmon resonance (FOLSPR) biosensor. Under optimal conditions, the results showed that the FOLSPR sensor detected HMGB1 with a wide linear range (10−10 to 10−6 g/mL), fast response (less than 10 min), and a low detection limit of 43.4 pg/mL (1.7 pM) and high correlation coefficient values (>0.9928). Furthermore, the accurate quantification and reliable validation of kinetic binding events measured by the currently working biosensors are comparable to surface plasmon resonance sensing systems, providing new insights into direct biomarker detection for clinical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Au and Pt atoms are preferentially deposited onto (1 0 0) and (1 1 1) planes of Pd NCs. • Formed conformal Pd/Au NCs and concave Pd/Pt NCs are used for catalyzing neutral GORs. • EQCM are employed for the in-situ measnuremt of GOR kinetics. • Pd/Pt CNC with Pt(2 1 0) plane has a remarkable activity for the sequential GOR. • Pd/Au NC shows a wide linear ranage for sensing glucose in the transisent GOR. Core-shell structures can improve the performance of electrocatalysts in fuel cells and biosensors owing to the tunable electron density of the shell metal by the core metal. In this study, Au and Pt atoms are preferentially deposited onto the (1 0 0) and (1 1 1) planes of the basal and truncated surfaces of Pd nanocubes (NCs), thus forming conformal Pd/Au NCs and concave Pd/Pt NCs (Pd/Pt CNCs), respectively. Furthermore, the activities and performances of these two core–shell NCs as catalysts in the sequential and transient catalysis of the d -glucose oxidation reaction (GOR) in the phosphate-buffered solution are studied. In the sequential catalysis in situ, an electrochemical quartz crystal microbalance is used. The Pd/Pt CNC with Pt-rich corners and the (2 1 0) plane exhibits remarkable specific activity (S A1 , 7.26 × 10–8 mol·cm−2) for the amount of bonded d -glucose per electrochemical active surface area (ECSA). Simultaneously, the catalyst has a significant specific activity (S A2 , 1.2 × 10–7 mol·cm−2) for the number of moles of released electrons involved in the GOR. In the transient GOR catalysis, the Pd/Au NC catalyst with Au (1 0 0) exhibits high sensitivity (S ECSA , 6.28 μA·mM−1·cm−2) for the present of d -glucose per ECSA in the wide linear range (0.25–14 mM). Furthermore, the Pd/Au NC exhibits its potential for high recoveries (99.23–100.14 %) and low relative standard deviation (≤1.08 %) in real sample tests for serum samples. [ABSTRACT FROM AUTHOR]

The availability of techniques for sensitive detection of early stage osteoarthritis is critical for improving patient health. This study illustrates the feasibility of a fiber-optic particle plasmon resonance (FOPPR) sensor with gold nanoparticles on the unclad region of optical fiber probes for analysis of osteoarthritis biomarkers, tumor necrosis factor-α (TNF-α) and matrix metalloproteinases-3 (MMP-3). Results show that the sensor can achieve a refractive index resolution of 5.18 × 10−7 RIU and limits of detection for TNF-α and MMP-3 as low as 8.22 pg ml−1 (0.48 pM) and 34.3 pg ml−1 (1.56 pM), respectively. Additionally, the FOPPR sensor shows a good correlation in determining TNF-α and MMP-3 in synovial fluid with the clinically accepted enzyme-linked immunosorbent assay (ELISA) method. Finally, given the FOPPR sensor's nature of being low-cost, label-free, highly sensitive, real-time, simple-to-operate, the FOPPR sensor could offer potential to monitor biomarkers of various diseases, and provide an ideal technical tool for point-of-care diagnostics. [ABSTRACT FROM AUTHOR]

In this research, a direct, simple and ultrasensitive fiber optic particle plasmon resonance (FOPPR) biosensing platform for immunoglobulin G (IgG) detection was developed using a gold nanoparticle/graphene oxide (AuNP/GO) composite as signal amplification element. To obtain the best analytical performance of the sensor, experimental parameters including the surface concentration of GO on the AuNPs, formation time of the GO, the concentration of the anti-IgG and incubation time of anti-IgG were optimized. The calibration plots displayed a good linear relationship between the sensor response (ΔI/I0) and the logarithm of the analyte concentrations over a linear range from 1.0 × 10−10 to 1.0 × 10−6 g/mL of IgG under the optimum conditions. A limit of detection (LOD) of 0.038 ng/mL for IgG was calculated from the standard calibration curve. The plot has a linear relationship (correlation coefficient, R = 0.9990). The analytical performance of present work's biosensor was better than that of our previously reported mixed self-assembled monolayer of 11-mercaptoundecanoic acid/6-mercapto-1-hexanol (MUA/MCH = 1:4) method by about three orders of magnitude. The achieved good sensitivity may be attributed to the synergistic effect between GO and AuNPs in this study. In addition, GO could immobilize more antibodies due to the abundant carboxylic groups on its surface. Furthermore, we also demonstrated that the results from this sensor have good reproducibility, with coefficients of variation (CVs) < 8% for IgG. Therefore, the present strategy provides a novel and convenient method for chemical and biochemical quantification and determination. [ABSTRACT FROM AUTHOR]