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1.
Biomed Eng Online ; 23(1): 33, 2024 Mar 15.
Artículo en Inglés | MEDLINE | ID: mdl-38491482

RESUMEN

The liver is the largest internal organ of the human body. It has a complex structure and function and plays a vital role in drug metabolism. In recent decades, extensive research has aimed to develop in vitro models that can simulate liver function to demonstrate changes in the physiological and pathological environment of the liver. Animal models and in vitro cell models are common, but the data obtained from animal models lack relevance when applied to humans, while cell models have limited predictive ability for metabolism and toxicity in humans. Recent advancements in tissue engineering, biomaterials, chip technology, and 3D bioprinting have provided opportunities for further research in in vitro models. Among them, liver-on-a-Chip (LOC) technology has made significant achievements in reproducing the in vivo behavior, physiological microenvironment, and metabolism of cells and organs. In this review, we discuss the development of LOC and its research progress in liver diseases, hepatotoxicity tests, and drug screening, as well as chip combinations. First, we review the structure and the physiological function of the liver. Then, we introduce the LOC technology, including general concepts, preparation materials, and methods. Finally, we review the application of LOC in disease modeling, hepatotoxicity tests, drug screening, and chip combinations, as well as the future challenges and directions of LOC.


Asunto(s)
Enfermedad Hepática Inducida por Sustancias y Drogas , Ingeniería de Tejidos , Animales , Humanos , Tecnología , Dispositivos Laboratorio en un Chip
2.
Chem Soc Rev ; 52(18): 6230-6253, 2023 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-37551138

RESUMEN

Electron, proton, and proton-coupled electron transfer (PCET) are crucial elementary processes in chemistry, electrochemistry, and biology. We provide here a gentle overview of retrospective and currently developing theoretical formalisms of chemical, electrochemical and biological molecular charge transfer processes, with examples of how to bridge electron, proton, and PCET theory with experimental data. We offer first a theoretical minimum of molecular electron, proton, and PCET processes in homogeneous solution and at electrochemical interfaces. We illustrate next the use of the theory both for simple electron transfer processes, and for processes that involve molecular reorganization beyond the simplest harmonic approximation, with dissociative electron transfer and inclusion of all charge transfer parameters. A core example is the electrochemical reduction of the S2O82- anion. This is followed by discussion of core elements of proton and PCET processes and the electrochemical dihydrogen evolution reaction on different metal, semiconductor, and semimetal (say graphene) electrode surfaces. Other further focus is on stochastic chemical rate theory, and how this concept can rationalize highly non-traditional behaviour of charge transfer processes in mixed solvents. As a second major area we address ("long-range") chemical and electrochemical electron transfer through molecular frameworks using notions of superexchange and hopping. Single-molecule and single-entity electrochemistry are based on electrochemical scanning probe microscopies. (In operando) scanning tunnelling microscopy (STM) and atomic force microscopy (AFM) are particularly emphasized, with theoretical notions and new molecular electrochemical phenomena in the confined tunnelling gap. Single-molecule surface structure and electron transfer dynamics are illustrated by self-assembled thiol molecular monolayers and by more complex redox target molecules. This discussion also extends single-molecule electrochemistry to bioelectrochemistry of complex redox metalloproteins and metalloenzymes. Our third major area involves computational overviews of molecular and electronic structure of the electrochemical interface, with new computational challenges. These relate to solvent dynamics in bulk and confined space (say carbon nanostructures), electrocatalysis, metallic and semiconductor nanoparticles, d-band metals, carbon nanostructures, spin catalysis and "spintronics", and "hot" electrons. Further perspectives relate to metal-organic frameworks, chiral surfaces, and spintronics.

3.
Nano Lett ; 22(12): 4854-4860, 2022 06 22.
Artículo en Inglés | MEDLINE | ID: mdl-35639869

RESUMEN

New nanostructures often reflect new and exciting properties. Here, we present an two-dimensional, hitherto unreported PdO square network with lateral dimensions up to hundreds of nanometers growing on reduced graphene oxide (rGO), forming a hybrid nanofilm. An intermediate state of dissolved Pd(0) in the bacterium S. oneidensis MR-1 is pivotal in the biosynthesis and inspires an abiotic synthesis. The PdO network shows a lattice spacing of 0.5 nm and a thickness of 1.8 nm on both sides of an rGO layer and is proposed to be cubic or tetragonal crystal, as confirmed by structural simulations. A 2D silver oxide analog with a similar structure is also obtained using an analogous abiotic synthesis. Our study thus opens a simple route to a whole new class of 2D metal oxides on rGO as promising candidates for graphene superlattices with unexplored properties and potential applications for example in electronics, sensing, and energy conversion.


Asunto(s)
Grafito , Nanoestructuras , Grafito/química , Nanoestructuras/química , Paladio/química
4.
Small ; 17(24): e2100558, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33978319

RESUMEN

V3 O7 ·H2 O nanobelts/reduced graphene oxide (rGO) composites (weight ratio: 86%/14%) are synthesized by a microwave approach with a high yield (85%) through controlling pH with acids. The growth mechanisms of the highly crystalline nanobelts (average diameter: 25 nm; length: ≈20 µm; oriented along the [101] direction) have been thoroughly investigated, with the governing role of the acid upon the morphology and oxidation state of vanadium disclosed. When used as the ZIB cathode, the composite can deliver a high specific capacity of 410.7 and 385.7 mAh g-1 at the current density of 0.5 and 4 A g-1 , respectively, with a high retention of the capacity of 93%. The capacity of the composite is greater than those of V3 O7 · H2 O, V2 O5 nanobelts, and V5 O12 · 6H2 O film. Zinc ion storage in V3 O7 ·H2 O/rGO is mainly a pseudocapacitive behavior rather than ion diffusion. The presence of rGO enables outstanding cycling stability of up to 1000 cycles with a capacity retention of 99.6%. Extended cycling shows a gradual phase transition, that is, from the original orthorhombic V3 O7 · H2 O to a stable hexagonal Zn3 (VO4 )2 (H2 O)2.93 phase, which is a new electrochemical route found in V3 O7 materials. This phase transition process provides new insight into the reactions of aqueous ZIBs.

5.
Chem Rev ; 119(16): 9509-9558, 2019 08 28.
Artículo en Inglés | MEDLINE | ID: mdl-31243999

RESUMEN

The ever-increasing demands for clean and sustainable energy sources combined with rapid advances in biointegrated portable or implantable electronic devices have stimulated intensive research activities in enzymatic (bio)fuel cells (EFCs). The use of renewable biocatalysts, the utilization of abundant green, safe, and high energy density fuels, together with the capability of working at modest and biocompatible conditions make EFCs promising as next generation alternative power sources. However, the main challenges (low energy density, relatively low power density, poor operational stability, and limited voltage output) hinder future applications of EFCs. This review aims at exploring the underlying mechanism of EFCs and providing possible practical strategies, methodologies and insights to tackle these issues. First, this review summarizes approaches in achieving high energy densities in EFCs, particularly, employing enzyme cascades for the deep/complete oxidation of fuels. Second, strategies for increasing power densities in EFCs, including increasing enzyme activities, facilitating electron transfers, employing nanomaterials, and designing more efficient enzyme-electrode interfaces, are described. The potential of EFCs/(super)capacitor combination is discussed. Third, the review evaluates a range of strategies for improving the stability of EFCs, including the use of different enzyme immobilization approaches, tuning enzyme properties, designing protective matrixes, and using microbial surface displaying enzymes. Fourth, approaches for the improvement of the cell voltage of EFCs are highlighted. Finally, future developments and a prospective on EFCs are envisioned.


Asunto(s)
Fuentes de Energía Bioeléctrica , Enzimas/química , Animales , Humanos , Modelos Teóricos , Oxidación-Reducción
6.
J Am Chem Soc ; 142(26): 11602-11609, 2020 07 01.
Artículo en Inglés | MEDLINE | ID: mdl-32510936

RESUMEN

Self-powered drug-delivery systems based on conductive polymers (CPs) that eliminate the need for external power sources are of significant interest for use in clinical applications. Osmium redox polymer-mediated glucose/O2 enzymatic biofuel cells (EBFCs) were prepared with an additional CP-drug layer on the cathode. On discharging the EBFCs in the presence of glucose and dioxygen, model drug compounds incorporated in the CP layer were rapidly released with negligible amounts released when the EBFCs were held at open circuit. Controlled and ex situ release of three model compounds, ibuprofen (IBU), fluorescein (FLU), and 4',6-diamidino-2-phenylindole (DAPI), was achieved with this self-powered drug-release system. DAPI released in situ in cell culture media was incorporated into retinal pigment epithelium (RPE) cells. This work demonstrates a proof-of-concept responsive drug-release system that may be used in implantable devices.


Asunto(s)
Fuentes de Energía Bioeléctrica , Liberación de Fármacos , Fluoresceína/metabolismo , Glucosa Oxidasa/metabolismo , Ibuprofeno/metabolismo , Indoles/metabolismo , Oxidorreductasas actuantes sobre Donantes de Grupo CH-CH/metabolismo , Aniones , Células Cultivadas , Técnicas Electroquímicas , Electrodos , Fluoresceína/química , Glucosa/química , Glucosa/metabolismo , Glucosa Oxidasa/química , Humanos , Ibuprofeno/química , Indoles/química , Osmio/química , Osmio/metabolismo , Oxidación-Reducción , Oxidorreductasas actuantes sobre Donantes de Grupo CH-CH/química , Oxígeno/química , Oxígeno/metabolismo , Polímeros/química , Polímeros/metabolismo , Epitelio Pigmentado de la Retina/citología , Epitelio Pigmentado de la Retina/metabolismo
7.
J Am Chem Soc ; 142(6): 3222-3230, 2020 02 12.
Artículo en Inglés | MEDLINE | ID: mdl-31999113

RESUMEN

A precisely localized enzyme cascade was constructed by integrating two sequential enzymes, glucoamylase (GA) and glucose oxidase (GOx), on a yeast cell surface through an a-agglutinin receptor as the anchoring motif with cohesin-dockerin interaction. The overall catalytic activities of the combinant strains were significantly dependent on the assembly method, enzyme molecular size, enzyme order, and enzyme stoichiometry. The combinant strain with GA-DocC initially bound scaffoldin prior to GOx-DocT exhibited a higher overall reaction rate. The highest overall reaction rate (29.28 ± 1.15 nmol H2O2 min-1mL-1) was achieved when GA/GOx ratio was 2:1 with enzyme order: yeast-GA-GOx-GA, 4-fold enhancement compared to free enzyme mixture. Further, the first example of starch/O2 enzymatic biofuel cells (EBFCs) using codisplayed GA/GOx based bioanodes were assembled, demonstrating excellent direct biomass-to-electricity conversion. The optimized EBFC registered an open-circuit voltage of 0.78 V and maximum power density (Pmax) of 36.1 ± 2.5 µW cm-2, significantly higher than the Pmax for other starch/O2 EBFCs reported so far. Therefore, this work highlights rational organization of sequential enzymes for enhanced biocatalytic activity and stability, which would find applications in biocatalysis, enzymatic biofuel cells, biosensing, and bioelectro-synthesis.


Asunto(s)
Biocatálisis , Fuentes de Energía Bioeléctrica , Enzimas Inmovilizadas/metabolismo , Glucano 1,4-alfa-Glucosidasa/metabolismo , Glucosa Oxidasa/metabolismo , Saccharomyces cerevisiae/metabolismo , Estabilidad de Enzimas , Cinética
8.
Mikrochim Acta ; 186(12): 853, 2019 11 28.
Artículo en Inglés | MEDLINE | ID: mdl-31781954

RESUMEN

An electrochemical method was designed for the determination and simultaneous reduction of 4-nitrophenol (4-NP). A nitrogen-rich carbon aerogel was synthesized from the precursor of phenol, formaldehyde and melamine. Then, copper nanoparticles were embedded into the aerogel, and the resulting material was used to modify a glassy carbon electrode (GCE), which displayed excellent electrocatalytic activity. Sensitive determination of 4-NP by cyclic voltammetry in 0.5 M sulfuric acid was accomplished. Among the various compositions of Cux@NC, the electrode modified with Cu3@NC showed the strongest reduction peak, typically at a potential of -0.30 V vs. reversible hydrogen electrode (RHE). A further study shows the cyclic voltammetry potential range to extend from -0.46 to +0.44 V (vs. RHE) at a scan rate of 100 mV s-1. Differential pulse voltammetric determination of 4-NP gave a lower detection limit of 53 nM and a current sensitivity of 0.7 µA µM-1 cm-2. The method was applied to the determination of 4-NP in spiked water samples, with comparable results of HPLC. The excellent performance was attributed to the highly graphitized structure of the aerogel with its large surface area and small pore size, and the presence of Cu-N structures as active sites. Graphical abstractSchematic representation of electrochemical determination and reduction of 4-nitrophenol under the glassy carbon electrode modified with highly dispersed Cu nanoparticles embedded on nitrogen-rich carbon aerogel. W: working electrode; R: reference electrode; C: counter electrode). Left: copper nanoparticles embedded in an aerogel.

9.
Analyst ; 139(2): 488-94, 2014 Jan 21.
Artículo en Inglés | MEDLINE | ID: mdl-24256634

RESUMEN

Nanoporous gold (NPG) based biosensors have been constructed by covalently immobilizing glucose oxidase (GOx) onto self-assembled monolayers (SAMs). With p-benzoquinone (BQ) as a mediator, diffusion behavior and amperometric biosensor performance are evaluated by electrochemical characterization. The enzyme modified electrodes are demonstrated to show a thickness-sensitive behavior. Compared with planar polycrystalline gold, the unique porous structure of NPG has also been characterized via an electrochemical surface reconstruction process. Single-crystal gold-like electrochemical behavior on NPG and a comprehensive understanding of its impacts on sensor performance have been proposed.


Asunto(s)
Técnicas Biosensibles/métodos , Glucosa/análisis , Oro/química , Nanoporos , Aspergillus niger/enzimología , Benzoquinonas/química , Técnicas Biosensibles/instrumentación , Difusión , Electroquímica , Electrodos , Glucosa Oxidasa/metabolismo , Humanos
10.
iScience ; 27(2): 108998, 2024 Feb 16.
Artículo en Inglés | MEDLINE | ID: mdl-38333690

RESUMEN

Self-sustained smart textiles require a miniaturized and flexible power source, while the state-of-the-art lithium-ion battery cannot be seamlessly integrated into smart textiles. Enzymatic biofuel cells (EBFC), utilizing physiological glucose or lactate as fuels to convert chemical energy into electricity, are a potential alternative power source. In comparison to other proposed energy harvesters relying on solar and biomechanical energy, EBFCs feature several key properties, including continuous power generation, biocompatible interfaces without using toxic elements, simple configuration without extra packaging, and biodegradability. There is an urgent need to introduce EBFCs to the researchers working on smart textiles, who typically are not expert on bioelectrochemistry. This minireview first introduces the working principle of EBFC and then summarizes its recent progress on fibers, yarns, and textiles. It's expected that this review can help to bridge the knowledge gap and provide the community of smart textiles with information on both the strengths and limitations of EBFCs.

11.
J Colloid Interface Sci ; 661: 164-174, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38295698

RESUMEN

Remediation of arsenic contamination is of great importance given the high toxicity and easy mobility of arsenic species in water and soil. This work reports a new and stable adsorbent for efficient elimination of arsenic by coating polyethyleneimine (PEI) molecules onto the surface of iron-doped birnessite (Fe-Bir). Characterization results of surface microstructure and crystalline feature (scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR) and X-ray photoelectron spectroscopy (XPS), etc.) suggest that Fe-Bir/PEI possesses a fine particle structure, inhibiting the agglomeration of birnessite-typed MnO2 and offering abundant active sites for arsenic adsorption. Fe-Bir/PEI is capable of working in a wide pH range from 3 to 11, with an efficient removal capacity of 53.86 mg/g at initial pH (pH0) of 7. Meanwhile, commonly coexisting anions (NO3-, SO42-, and Cl-) and cations (Na+, K+, Ca2+ and Mg2+) pose no effect on the arsenic removal performance of Bir/PEI. Fe-Bir/PEI exhibits a good reusability for arsenic removal with low Mn and Fe ions leaching after 5 cycles. Besides, Fe-Bir/PEI possesses efficient remediation capability in simulated As-contaminated soil. The modification of PEI in Fe-Bir/PEI can adsorb newly formed As(V), which is impossible for the adsorbent without PEI. Further, the arsenic removal mechanism of Fe-Bir/PEI is revealed with redox effect, electrostatic attraction and hydrogen bonding.

12.
Biosens Bioelectron ; 246: 115890, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38048721

RESUMEN

Real-time monitoring of health conditions is an emerging strong issue in health care, internet information, and other strongly evolving areas. Wearable electronics are versatile platforms for non-invasive sensing. Among a variety of wearable device principles, fiber electronics represent cutting-edge development of flexible electronics. Enabled by electrochemical sensing, fiber electronics have found a wide range of applications, providing new opportunities for real-time monitoring of health conditions by daily wearing, and electrochemical fiber sensors as explored in the present report are a promising emerging field. In consideration of the key challenges and corresponding solutions for electrochemical sensing fibers, we offer here a timely and comprehensive review. We discuss the principles and advantages of electrochemical sensing fibers and fabrics. Our review also highlights the importance of electrochemical sensing fibers in the fabrication of "smart" fabric designs, focusing on strategies to address key issues in fiber-based electrochemical sensors, and we provide an overview of smart clothing systems and their cutting-edge applications in therapeutic care. Our report offers a comprehensive overview of current developments in electrochemical sensing fibers to researchers in the fields of wearables, flexible electronics, and electrochemical sensing, stimulating forthcoming development of next-generation "smart" fabrics-based electrochemical sensing.


Asunto(s)
Técnicas Biosensibles , Dispositivos Electrónicos Vestibles , Electrónica
13.
RSC Adv ; 13(15): 9903-9917, 2023 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-37034448

RESUMEN

Bio-slurry remediation technology, as a controllable bioremediation method, has the significant advantage of high remediation efficiency and can effectively solve the problems of high energy consumption and secondary pollution of traditional organic pollution site remediation technology. To further promote the application of this technology in the remediation of organically polluted soil, this paper summarizes the importance and advantages of bio-slurry remediation technology compared with traditional soil remediation technologies (physical, chemical, and biological). It introduces the technical infrastructure and its technological processes. Then, various factors that may affect its remediation performance are discussed. By analyzing the applications of this technology to the remediation of typical organic pollutant-(polycyclic aromatic hydrocarbons(PAHs), polychlorinated biphenyls(PCBs), total petroleum hydrocarbons(TPH), and pesticide) contaminated sites, the following key features of this remediation technology are summarised: (1) the technology has a wide range of applications and can be used in a versatile way in the remediation projects of various types of organic-contaminated soil sites such as in clay, sand, and high organic matter content soil; (2) the technology is highly controllable. Adjusting environmental parameters and operational conditions, such as nutrients, organic carbon sources (bio-stimulation), inoculants (bio-augmentation), water-to-soil ratio, etc., can control the remediation process, thus improving the restoration performance. To sum up, this bio-slurry remediation technology is an efficient, controllable and green soil remediation technology that has broad application prospects.

14.
Bioresour Technol ; 389: 129813, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37776913

RESUMEN

Anodic electro-fermentation (AEF), where an anode replaces the terminal electron acceptor, shows great promise. Recently a Lactococcus lactis strain blocked in NAD+ regeneration was demonstrated to use ferricyanide as an alternative electron acceptor to support fast growth, but the need for high concentrations of this non-regenerated electron acceptor limits practical applications. To address this, growth of this L. lactis strain, and an adaptively evolved (ALE) mutant with enhanced ferricyanide respiration capacity were investigated using an anode as electron acceptor in a bioelectrochemical system (BES) setup. Both strains grew well, however, the ALE mutant significantly faster. The ALE mutant almost exclusively generated 2,3-butanediol, whereas its parent strain mainly produced acetoin. The ALE mutant interacted efficiently with the anode, achieving a record high current density of 0.81 ± 0.05 mA/cm2. It is surprising that a Lactic Acid Bacterium, with fermentative metabolism, interacts so well with an anode, which demonstrates the potential of AEF.

15.
Anal Methods ; 15(36): 4767-4776, 2023 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-37697917

RESUMEN

In order to achieve rapid, sensitive, and high-throughput determination of typical semi-volatile organic compounds (SVOCs) in soil samples, a method for the rapid determination of 63 SVOCs in soil was developed by optimizing and improving the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) extraction technique in conjunction with gas chromatography-mass spectrometry (GC-MS) analysis. A small amount of soil sample (5.0 g) was vortexed with 10 mL of a mixture of acetone and n-hexane (V/V = 1 : 1) for 2 min, followed by rapid vortex purification and centrifugation using a mixture of copper powder and octadecylsilane (C18) dispersant. The resulting supernatant was then purified through a 0.22 µm filter membrane. The results showed that the 63 SVOCs exhibited good linear relationships within the concentration range of 100-5000 µg L-1, with correlation coefficients (R2) above 0.99. The method detection limit (MDL = 3.3 Sy/m) was lower than 0.050 mg kg-1. At a spike concentration of 1 mg kg-1, the recovery rates of the 63 SVOCs were almost above 70% (n = 7). Compared with the rapid solvent extraction (ASE) method specified in US EPA 3545 standard, this method reduced the organic solvent usage by 14 times and significantly shortened the operation time. Furthermore, this method did not involve any transfer or concentration steps of the extractant during the experimental process, reducing the exposure time of toxic compounds and providing support for the principles of green analytical chemistry. Moreover, in the detection of most compounds in the same batch of contaminated soil, the extraction results obtained by QuEChERS were superior to those obtained by the ASE method, providing evidence for the practical application of this method. This method is rapid, simple, accurate, requires a small sample volume, and causes minimal environmental pollution. It provides a high-throughput detection method for the rapid screening of SVOCs in soil.

16.
Microb Biotechnol ; 16(6): 1277-1292, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-36860178

RESUMEN

Lactococcus lactis, a lactic acid bacterium with a typical fermentative metabolism, can also use oxygen as an extracellular electron acceptor. Here we demonstrate, for the first time, that L. lactis blocked in NAD+ regeneration can use the alternative electron acceptor ferricyanide to support growth. By electrochemical analysis and characterization of strains carrying mutations in the respiratory chain, we pinpoint the essential role of the NADH dehydrogenase and 2-amino-3-carboxy-1,4-naphtoquinone in extracellular electron transfer (EET) and uncover the underlying pathway systematically. Ferricyanide respiration has unexpected effects on L. lactis, e.g., we find that morphology is altered from the normal coccoid to a more rod shaped appearance, and that acid resistance is increased. Using adaptive laboratory evolution (ALE), we successfully enhance the capacity for EET. Whole-genome sequencing reveals the underlying reason for the observed enhanced EET capacity to be a late-stage blocking of menaquinone biosynthesis. The perspectives of the study are numerous, especially within food fermentation and microbiome engineering, where EET can help relieve oxidative stress, promote growth of oxygen sensitive microorganisms and play critical roles in shaping microbial communities.


Asunto(s)
Lactococcus lactis , Transporte de Electrón , Lactococcus lactis/genética , Lactococcus lactis/metabolismo , Electrones , Fermentación , Ferricianuros/metabolismo , Oxígeno/metabolismo
17.
Animals (Basel) ; 12(9)2022 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-35565649

RESUMEN

Camera trapping and video recording are now ubiquitous in the study of animal ecology. These technologies hold great potential for wildlife tracking, but are limited by current learning approaches, and are hampered by dependence on large samples. Most species of wildlife are rarely captured by camera traps, and thus only a few shot samples are available for processing and subsequent identification. These drawbacks can be overcome in multiobject tracking by combining wildlife detection and tracking with few-shot learning. This work proposes a multiobject-tracking approach based on a tracking-by-detection paradigm for wildlife to improve detection and tracking performance. We used few-shot object detection to localize objects using a camera trap and direct video recordings that could augment the synthetically generated parts of separate images with spatial constraints. In addition, we introduced a trajectory reconstruction module for better association. It could alleviate a few-shot object detector's missed and false detections; in addition, it could optimize the target identification between consecutive frames. Our approach produced a fully automated pipeline for detecting and tracking wildlife from video records. The experimental results aligned with theoretical anticipation according to various evaluation metrics, and revealed the future potential of camera traps to address wildlife detection and tracking in behavior and conservation.

18.
ChemElectroChem ; 9(17): e202200319, 2022 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-36246851

RESUMEN

Electrochemical methods can be used to selectively modify the surfaces of electrodes, enabling the immobilisation of enzymes on defined areas on the surfaces of electrodes. Such selective immobilisation methods can be used to pattern catalysts on surfaces in a controlled manner. Using this approach, the selective patterning of the enzyme glucose oxidase on the electrodes was used to develop a flow reactor for the controlled delivery of the oxidant H2O2. GOx was immobilised on a glassy carbon electrode using polypyrrole, silica films, and diazonium linkers. The rate of production of H2O2 and the stability of the response was dependent on the immobilisation method. GOx encapsulated in polypyrrole was selected as the optimal method of immobilisation, with a rate of production of 91±11 µM h-1 for 4 hours of continuous operation. The enzyme was subsequently immobilised on carbon rod electrodes (surface area of 5.76 cm2) using a polypyrrole/Nafion® film and incorporated into a flow reactor. The rate of production of H2O2 was 602±57 µM h-1, with 100 % retention of activity after 7 h of continuous operation, demonstrating that such a system can be used to prepare H2O2 at continuous and stable rate for use in downstream oxidation reactions.

19.
Biosensors (Basel) ; 12(4)2022 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-35448288

RESUMEN

The solid contact ion-selective electrode (ISE) is a promising skin-interfaced monitoring system for sweat ions. Despite a growing number of on-body usages of ISE with fancy new materials and device fabrications, there are very few reports attempting to validate ISE results with a gold standard technique. For this purpose, this work uses inductively coupled plasma-optical emission spectrometry (ICP-OES) as a reference technique to conduct a direct evaluation of the sweat sodium and potassium ion levels obtained by ISE in an off-body approach. Eight healthy male subjects were recruited to collect exercise-induced sweat. It was found that sweat sodium and potassium ions present a rather wide concentration range. The sweat sodium concentration did not vary greatly in an exercise period of half an hour, while the sweat potassium concentration typically decreased with exercise. Mineral drink intake had no clear impact on the sweat sodium level, but increased the sweat potassium level. A paired t-test and mean absolute relative difference (MARD) analysis, a method typically used for evaluating the performance of glucometers, was employed to compare the results of ISE and ICP-OES. The statistical analysis validated the feasibility of ISE for measuring sweat ions, although better accuracy is required. Our data suggests that overweight subjects are likely to possess a higher sweat sodium level.


Asunto(s)
Electrodos de Iones Selectos , Sudor , Humanos , Iones , Masculino , Potasio/análisis , Sodio/análisis , Sudor/química
20.
Colloids Surf B Biointerfaces ; 220: 112941, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36270138

RESUMEN

Multi-functional small molecules attached to an electrode surface can bind non-covalently to the redox enzyme fructose dehydrogenase (FDH) to ensure efficient electrochemical electron transfer (ET) and electrocatalysis of the enzyme in both mediated (MET) and direct (DET) ET modes. The present work investigates the potential of exploiting secondary, electrostatic and hydrophobic interactions between substituents on a small molecular bridge and the local FDH surfaces. Such interactions ensure alignment of the enzyme in an orientation favourable for both MET and DET. We have used a group of novel synthesized anthraquinones as the small molecule bridge, functionalised with electrostatically neutral, anionic, or cationic substituents. Particularly, we investigated the immobilisation of FDH on a nanoporous gold (NPG) electrode decorated with the novel synthesised anthraquinones using electrochemical methods. The best DET-capable fraction out of four anthraquinone derivatives tested is achieved for an anthraquinone functionalised with an anionic sulphonate group. Our study demonstrates, how the combination of chemical design and bioelectrochemistry can be brought to control alignment of enzymes in productive orientations on electrodes, a paradigm for thiol modified surfaces in biosensors and bioelectronics.


Asunto(s)
Técnicas Biosensibles , Deshidrogenasas de Carbohidratos , Antraquinonas , Deshidrogenasas de Carbohidratos/química , Deshidrogenasas de Carbohidratos/metabolismo , Electrodos , Transporte de Electrón , Electrones , Enzimas Inmovilizadas/química , Fructosa/química , Fructosa/metabolismo
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