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Background: Non-specific lipid transfer proteins (nsLTPs) are a group of small and basic proteins that can bind and transfer various lipid molecules to the apoplastic space. A typical nsLTP carries a conserved architecture termed eight-cysteine motif (8CM), a scaffold of loop-linked helices folding into a hydrophobic cavity for lipids binding. Encoded by a multigene family, nsLTPs are widely distributed in terrestrial plants from bryophytes to angiosperms with dozens of gene members in a single species. Although the nsLTPs in the most primitive plants such as Marchantia already reach 14 members and are divergent enough to form separate groups, so far none have been identified in any species of green algae. Results: By using a refined searching strategy, we identified putative nsLTP genes in more than ten species of green algae as one or two genes per haploid genome but not in red and brown algae. The analyses show that the algal nsLTPs carry unique characteristics, including the extended 8CM spacing, larger molecular mass, lower pI value and multiple introns in a gene, which suggests that they could be a novel nsLTP lineage. Moreover, the results of further investigation on the two Chlamydomonas nsLTPs using transcript and protein assays demonstrated their late zygotic stage expression patterns and the canonical nsLTP properties were also verified, such as the fatty acids binding and proteinase resistance activities. Conclusions: In conclusion, a novel nsLTP lineage is identified in green algae, which carries some unique sequences and molecular features that are distinguishable from those in land plants. Combined with the results of further examinations of the Chlamydomonas nsLTPs in vitro, possible roles of the algal nsLTPs are also suggested. This study not only reveals the existence of the nsLTPs in green algae but also contributes to facilitating future studies on this enigmatic protein family. [ABSTRACT FROM AUTHOR]

[Display omitted] • Core-shell PdAu Oct, t -Oct, and NC are successfully prepared. • Specific activities of these PdAu nanocrystals as glucose sensors are studied. • The GOR kinetics on these PdAu nanocrystals are studied using EQCM. • PdAu t -Oct with (2 1 1) planes is the best catalyst for bonding with glucose. • Facile electron transfer of GOR occurs on the PdAu Oct. Core-shell PdAu octahedrons (Oct), PdAu truncated octahedrons (t -Oct), and PdAu nanocubes (NC) were successfully synthesised, and their specific activities, in terms of electrochemical surface area (ECSA), in the glucose oxidation reaction (GOR) and glucose sensors were systematically studied. Kinetic studies using electrochemical quartz crystal microbalance show that the specific activities (S A 1) of the nanocrystals were in the order of t -Oct > Oct > NC, in which the number of moles of glucose per ECSA for PdAu t -Oct was 2.56 × 10-8 mol·cm−2, indicating that glucose was easily bonded to t -Oct with the (2 1 1) facet. By contrast, the results of specific activity (S A 2), estimated by the moles of electrons over ECSA, showed the order of Oct > t -Oct > NC. The S A 2 of PdAu Oct was 6.25 × 10-7 mol·cm−2. The facile electron transfer of GORs occurred via PdAu Oct with an electron-rich Au shell. Additionally, PdAu Oct demonstrated high recoveries when used as a glucose sensor for energy drinks. [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]

We present the design and experimental verification of a self-referencing dual-channel fiber optic particle plasmon resonance (FOPPR) sensing system for compensation of thermal and bulk-composition effects as well as nonspecific adsorption in real-time biosensing of complex samples. A theoretical model is first proposed and then a systematic experimental approach is used to verify the model. The sensing system comprises an analysis fiber sensor and a reference fiber sensor in a single microfluidic chip, where the analysis fiber is functionalized with a recognition molecule. The compensation still works even if the surface coverages of gold nanoparticles on the reference and analysis fibers are not exactly the same. The potential of this approach is illustrated by a model biosensing experiment in which the detection of anti-biotin is compensated for bulk refractive index change, nonspecific adsorption and/or color interference, in various sample media. The percent recovery is 103.2% under both the effects of bulk refractive index change and nonspecific adsorption and is 93.9% under both the effects of color interference and nonspecific adsorption, suggesting that the compensation is effective. [ABSTRACT FROM AUTHOR]

Carbon electrode materials have been widely explored with surface functionalization to find novel properties and electrochemical applications. The study reports ionic lead (Pb2+) detection over bismuth (Bi) and nitrogen (N) atomically co-doped graphene oxide (GO) flakes in an electrochemical sensor and their facile synthesis by a combined wet chemical and photochemical process. Both surface state and electronic transition manipulated by the heteroatom doping were characterized by spectroscopic analyses. The Bi- and N-added GO sensors exhibited a relatively higher sensitivity for the detection of Pb2+ ions in acetate buffer solution than the bare GO one as measured by square wave anodic stripping voltammetry (SWASV), and their stripping current and potential are dependent upon the dopant content. The Bi and N co-doped GO electrode showed a noticeable electrocatalytic activity toward Pb2+ detection compared with the singly Bi- and N-doped GO ones as measured by cyclic voltammetry (CV). Formation of electroactive Bi and N dual sites exerts a major influence on the adsorption of Pb2+ ions and deposition-stripping process, and their synergistic interaction in the electron transfer and catalysis is responsible for the remarkably enhanced sensing activity. The co-doped GO sensor reveals a linear dependence of the current response and peak potential on the Pb2+ concentration and offers sensitive assaying of Pb2+ ions with a quite low limit of detection (LOD) of 10.9 pM and low limit of quantification (LOQ) of 36.4 pM. Its analytical performance with good selectivity against several interfering ions and determination in tap water samples was acquired. Results demonstrate the feasibility of coupling metal with nonmetal co-dopants to tailor the electrical conduction and surface reactivity of the two-dimensional (2D) carbon materials toward efficient sensing operation. [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]

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]