Self-powered biosensing sutures for real-time wound monitoring.

Effective wound management has the potential to reduce both the duration and cost of wound healing. However, traditional methods often rely on direct observation or complex and expensive biological testing to monitor and evaluate the invasive damage caused by wound healing, which can be time-consuming. Biosensors offer the advantage of precise and real-time monitoring, but existing devices are not suitable for integration with sensitive wound tissue due to their external dimensions. Here, we have designed a self-powered biosensing suture (SPBS) based on biofuel cells to accurately monitor glucose concentration at the wound site and promote wound healing. The anode of the SPBS consists of carbon nanotubes-modified carbon fibers, tetrathiafulvalene (TTF), and glucose oxidase (GOx), while the cathode is composed of Ag2O and carbon nanotubes modified nanotubes modified carbon fibers. It was observed that SPBS exhibited excellent physical and chemical stability in vitro. Regardless of different bending degrees or pH values, the maximum power density of SPBS remained above 92%, which is conducive to long-term dynamic evaluation. Furthermore, the voltage generated by SPBS reflects blood glucose concentration, and measurements at wound sites are consistent with those obtained using a commercially available blood glucose meter. SPBS achieves the healing effect of traditional medical sutures after complete healing within 14 days. It offers valuable insights for intelligent devices dedicated to real-time wound monitoring.

Defect-Enriched Graphene Nanoribbons Tune the Adsorption Behavior of the Mediator to Boost the Lactate/Oxygen Biofuel Cell.

Owing to the high efficiency and specificity in moderate conditions, enzymatic biofuel cells (EBFCs) have gained significant interest as a promising energy source for wearable devices. However, the instability of the bioelectrode and the lack of efficient electrical communication between the enzymes and electrodes are the main obstacles. Herein, defect-enriched 3D graphene nanoribbons (GNRs) frameworks are fabricated by unzipping multiwall carbon nanotubes, followed by thermal annealing. It is found that defective carbon shows stronger adsorption energy towards the polar mediators than the pristine carbon, which is beneficial to improving the stability of the bioelectrodes. Consequently, the EBFCs equipped with the GNRs exhibit a significantly enhanced bioelectrocatalytic performance and operational stability, delivering an open-circuit voltage and power density of 0.62 V, 70.7 µW/cm2, and 0.58 V, 18.6 µW/cm2 in phosphate buffer solution and artificial tear, respectively, which represent the high levels among the reported literature. This work provides a design principle according to which defective carbon materials could be more suitable for the immobilization of biocatalytic components in the application of EBFCs.

Application of nanopore adaptive sequencing in pathogen detection of a patient with Chlamydia psittaci infection.

Introduction: Nanopore sequencing has been widely used in clinical metagenomic sequencing for pathogen detection with high portability and real-time sequencing. Oxford Nanopore Technologies has recently launched an adaptive sequencing function, which can enrich on-target reads through real-time alignment and eject uninteresting reads by reversing the voltage across the nanopore. Here we evaluated the utility of adaptive sequencing in clinical pathogen detection. Methods: Nanopore adaptive sequencing and standard sequencing was performed on a same flow cell with a bronchoalveolar lavage fluid sample from a patient with Chlamydia psittacosis infection, and was compared with the previous mNGS results. Results: Nanopore adaptive sequencing identified 648 on-target stop receiving reads with the longest median read length(688bp), which account for 72.4% of all Chlamydia psittaci reads and 0.03% of total reads in enriched group. The read proportion matched to C. psittaci in the stop receiving group was 99.85%, which was much higher than that of the unblock (<0.01%) and fail to adapt (0.02%) groups. Nanopore adaptive sequencing generated similar data yield of C. psittaci compared with standard nanopore sequencing. The proportion of C. psittaci reads in adaptive sequencing is close to that of standard nanopore sequencing and mNGS, but generated lower genome coverage than mNGS. Discussion: Nanopore adaptive sequencing can effectively identify target C. psittaci reads in real-time, but how to increase the targeted data of pathogens still needs to be further evaluated.

Carbon nanorods assembled coral-like hierarchical meso-macroporous carbon as sustainable materials for efficient biosensing and biofuel cell.

Sustainable conversion of renewable biomass into high-performance electrode materials has attracted extensive scientific and technological attention. However, to our knowledge, the potential of biomass derived carbon in biosensors and biofuel cells (BFCs) developments remains to be explored. Herein, the carbon nanorods assembled coral-like hierarchical meso-macroporous carbon (CN-CHMC) was synthesized as a sustainable electrode material to construct biosensor and lactate/air BFC. The CN-CHMC from cucumber (Cucumis sativus) possesses porous structure and plentiful defects, which not only facilitate the effective immobilization of enzymes but also accelerate electron transfer on the bioelectrode surfaces. As an electrochemical lactate biosensor, the CN-CHMC-based biosensor exhibits a wider linear range with lower detection limit (3.6 µM) and higher sensitivities (57.18 and 30.99 µA mM-1 cm-2) compared to carbon nanotube (CNT)-based biosensor. The feasibility of CN-CHMC-based biosensor in practical analysis is demonstrated by detecting lactate contents in real samples. By coupling with bilirubin oxidase-based biocathode, the lactate/air BFC equipped with CN-CHMC reveals a higher output power (112.7 µW cm-2) than that of CNT-based BFC. More interestingly, the lactate/air BFC demonstrates the ability to harvest energy from multi-component samples. The application of CN-CHMC may provide a new avenue to synthesize electrode materials with economical cost and excellent electrochemical activity.

Nucleic Acid-Based Cell Surface Engineering Strategies and Their Applications.

The cell membrane is a biological interface regulating the communications between cells and their environment. The ability to functionalize the cell membrane with molecules or nanomaterials allows us to manipulate cellular behaviors and to expand cellular functions. Due to their unique merits of synthetic accessibility, flexible design, and precise programmability, nucleic acids provide an emerging and promising molecular toolkit for cell surface engineering. In this review, the recent progress in nucleic acid-based cell surface engineering are summarized. We first introduce approaches to nucleic acid-based cell surface engineering, including monovalent and polyvalent surface engineering strategies. Then, the biological applications of nucleic acid-based cell surface engineering in biosensing of extracellular microenvironment, programming cell-cell interactions, and mimicking cellular behaviors are reviewed. Finally, we analyze the current challenges existing in this area and discuss the prospects for the future development.

Hybrid catalyst cascade for enhanced oxidation of glucose in glucose/air biofuel cell.

Redox enzymes are capable of harvesting electrical energy from biofuels in high catalytic activity and under mild condition. However, it is difficult to achieve efficient electron transfer and deep oxidation of biofuels simultaneously in a single-enzyme catalytic system. Herein, we report a hybrid catalyst cascade consisting of an organic oxidation catalyst, 2,2,6,6-tetramethyl-1-piperidine N-oxyl (TEMPO), and an enzyme, glucose oxidase (GOx), for electrochemical oxidation of glucose. It is found that TEMPO is capable of mediating electron transfer between the redox center of GOx and the electrode surface. While glucose can be oxidized into glucuronic acid under neutral conditions. Thus, combining GOx and TEMPO, we are able to achieve 4e- electrooxidation of glucose using the hybrid enzymatic and organic cascade (HEOC) system. When coupled with an air-breathing Pt cathode, the resulting glucose/air biofuel cell using the proposed HEOC anode exhibits a maximum power density of 38.1 µW cm-2 with a short-circuit current of 651.4 µA cm-2, which can be attributed to the enhanced energetic efficiency, enabling TEMPO a promising catalyst for glucose oxidation in bioelectronics applications.

DNA derived N-doped 3D conductive network with enhanced electrocatalytic activity and stability for membrane-less biofuel cells.

Enzymes are promising electrocatalysts in many biological processes. We proposed two strategies, co-immobilization and three-dimensional (3D) space design, to strengthen electron transfer (ET). In this research, DNA base and CNT were mixed in an aqueous solution; then the mixture was dried and ground. Finally, the powder was annealed in N2 to obtain DNA derived N-doped 3D conductive network (N-G@CNT). N-G@CNT immobilized mediators on itself through adsorption. Such 3D space structure shows high activity toward a set of critical electrochemical reactions and high-performance in enzymatic biofuel cells (EBFCs). It is found that N-G@CNT conductive network possesses an interconnected porous structure and well-developed porosity. As a result, the membrane-less EBFCs equipped with enzyme/mediator co-immobilization N-G@CNT bioelectrodes were measured in a model 5 mM glucose-containing aqueous solution, human serum, and rabbit whole blood, respectively, which can generate 0.34, 0.078, and 0.15 mW cm-2 power density, respectively. The constant-current discharge method carried out in a model 5 mM glucose-containing aqueous solution shows that the discharge time reached 19 h at a discharge current density of 0.01 mA cm-2. The membrane EBFCs can deliver a high open circuit voltage of 0.68 V, a short-circuit current density of 2 mA cm-2, and a maximum power density of 0.5 mW cm-2.

Rational design of N-doped CNTs@C3N4 network for dual-capture of biocatalysts in enzymatic glucose/O2 biofuel cells.

Carbonaceous materials are promising electrode materials for enzymatic biofuel cells (EBFCs) due to their excellent electrical conductivity, chemical and physical stability and biocompatibility. Design and preparation of carbon materials with a hollow structure and a rough surface are of great significance for immobilization of enzymes both inside and outside the carbon materials for EBFC applications. We report herein the synthesis of novel carbonaceous materials consisting of bamboo-shaped hollow N-doped carbon nanotubes (N-CNTs) and C3N4 nanosheets (denoted as N-CNTs@C3N4) as electrode materials for dual-capture of enzymes in glucose/O2 EBFCs. The combination of one-dimensional N-CNTs with an open structure and two-dimensional C3N4 nanosheets forms a three-dimensional crosslinking network that significantly enhances the immobilization of enzymes, electrode stability, and mass transfer of substrates, thus boosting the EBFC performance. As a result, EBFCs equipped with N-CNTs@C3N4 can generate a high open circuit potential of 0.93 V and output a maximum power density of 0.57 mW cm-2 at 0.47 V. Additionally, the as-fabricated glucose/O2 EBFCs are capable of directly harvesting energy from various soft drinks, which indicates the promising applications of the N-CNTs@C3N4 nanocomposite as an electrode material for EBFCs.

Deep oxidization of glucose driven by 4-acetamido-TEMPO for a glucose fuel cell at room temperature.

Exploiting suitable oxidation catalysts is of great importance in the development of sugar-based fuel cells (SFCs). Herein, a novel room-temperature glucose/O2 fuel cell (GFC), which employs 4-acetamido-2,2,6,6-tetramethylpiperidin-1-oxyl (ACT) as an anodic electrocatalyst and air-breathing Pt-C as a cathode, is demonstrated. Under room temperature operation, the as-assembled GFCs are capable of delivering a maximum power density of 100 µW cm-2 in the presence of 50 mM glucose. Bulk electrolysis products of glucose identified by mass spectrum and Fourier transform infrared spectroscopy include gluconic acid and glucaric acid, suggesting that the aldehyde and primary hydroxy groups of glucose can be deeply oxidized into carboxyl groups through a 6e- pathway. The deep glucose oxidation capability makes ACT a promising anodic electrocatalyst for SFCs.

Sweet potato derived three-dimensional carbon aerogels with a hierarchical meso-macroporous and branching nanostructure for electroanalysis.

In this paper, sweet potatoes (Ipomoea batatas) are used as low-cost precursors to synthesize carbon aerogels with a hierarchical meso-macroporous and branching nanostructure (HMM-BNCA). An HMM-BNCA-modified glassy carbon electrode (GCE) (HMM-BNCA/GCE) exhibits high electrocatalytic activity for some electroactive biomolecules. For ascorbic acid (AA), the HMM-BNCA/GCE exhibits low oxidation peak potential and detection limit (-0.005 V and 0.45 µM, S/N = 3), high sensitivities (195.43 and 121.00 µA mM-1 cm-2) and wide linear ranges (10-1250 µM and 1250-4750 µM), which are superior to those obtained at the GCE and carbon nanotube (CNT)-modified GCE (CNT/GCE). The HMM-BNCA/GCE exhibits significant resistance to fouling and the interfering substances for the detection of AA. The successful and accurate detection of AA in real samples (such as vitamin C injections and vitamin C soft drinks) in this work demonstrates the feasibility and tremendous potential of HMM-BNCA/GCE for the analysis of AA in complex systems.

Biomass derived worm-like nitrogen-doped-carbon framework for trace determination of toxic heavy metal lead (II).

The worm-like nitrogen-doped-carbon framework (WNCF) with abundant edge-plane-like defective sites (EDSs) was synthesized by using natural wax gourd (Benincasa hispida) as the main carbon precursor and milk yielded by Chinese Holstein cattle (Holstein Friesian) as the nitrogen precursor for the first time. The Nafion-dispersed WNCF (Nafion-WNCF) was employed to design a highly sensitive electrochemical sensor for the trace determination of toxic heavy metal lead (II) (Pb2+) by the differential pulse anodic stripping voltammetry (DPASV). Some key experimental factors including calcination temperature of WNCF, pH value of the buffer solution, deposition potential, deposition time and the concentration of bismuth (Bi3+) were optimized for the stripping analysis of Pb2+. Under the optimum experimental condition, Nafion-WNCF modified bismuth film glassy carbon electrode (Nafion-WNCF/BFGCE) exhibits a wide linear range from 0.5 µg L-1 to 100 µg L-1 and a low detection limit of 0.2 µg L-1 (S/N = 3) for detecting Pb2+. Especially, Nafion-WNCF/BFGCE was successfully applied to determine Pb2+ in tap water and lake water samples. All the results suggest that the WNCF can be considered as a green and low-cost nanomaterial for the precision detection of Pb2+ in real samples.

A novel microcurrent dressing for wound healing in a rat skin defect model.

BACKGROUND: The exogenous application of low-intensity electric stimulation (ES) may mimic a natural endogenous bioelectric current and accelerate the repair process of skin wounds. This study designed a novel microcurrent dressing (MCD) and evaluated its potential effects on wound healing in a rat skin defect model. METHODS: First, wireless ES was integrated into a medical cotton cushion to fabricate the MCD, and its electrical property was examined by using a universal power meter. Then, animal experiments were conducted to evaluate the MCD's effect. Forty-five rats were randomized into control (Con) group, Vaseline gauze (VG) group and MCD group. A full-thickness round skin incision 1.5 cm in diameter was made on the back of each animal. Apart from routine disinfection, the Con rats were untreated, whereas the other two groups were treated with VG or MCD. On days 3, 7 and 14 post injury, the wound areas were observed and measured using image analysis software following photography, and the skin samples were harvested from wound tissue. Then, histopathological morphology was observed routinely by hematoxylin and eosin (HE) staining; tumor necrosis factor α (TNF-α) and interleukin (IL)-1ß expression were detected by Western blotting. Vascular endothelial growth factor (VEGF) and epidermal growth factor (EGF) expression were detected with immunohistochemistry. RESULTS: The MCD generated a sf electric potential greater than 0.95 V. Animal experiments showed that the wound-healing rate in the MCD group was significantly increased compared with the Con and VG groups (P < 0.05 or P < 0.01). Histopathological observation revealed an alleviated inflammatory response, induced vascular proliferation and accelerated epithelization in the MCD group. Moreover, samples from the MCD group expressed reduced TNF-α and IL-1ß levels and increased VEGF and EGF levels compared with those of the other two groups (P < 0.05 or P < 0.01). However, no significant difference was noted between the Con and VG groups at each time point. CONCLUSIONS: The MCD generates a stable and lasting ES and significantly promotes wound healing by reducing inflammation duration and increasing growth factors expression. Thus, MCD may act as a promising biomaterial device for skin wound healing.

Green and low-cost synthesis of nitrogen-doped graphene-like mesoporous nanosheets from the biomass waste of okara for the amperometric detection of vitamin C in real samples.

In this work, the low-cost nitrogen-doped graphene-like mesoporous nanosheets (N-GMNs) was synthesized from the biomass waste of okara for the first time for the construction of a nonenzymatic amperometric vitamin C biosensor. The N-GMNs modified glassy carbon electrode (N-GMNs/GCE) shows much lower overpotential for the electrooxidation of vitamin C comparing to the traditional GCE as well as the GCE modified by carbon nanotubes (CNTs/GCE), indicating the promising of N-GMNs/GCE for the sensitive and selective nonenzymatic amperometric vitamin C biosensing. As a nonenzymatic amperometric biosensor for vitamin C, the N-GMNs/GCE shows a higher sensitivity (144.65 µA mM-1 cm-2), a wider linear range (10-5640 µmol L-1) and a lower detection limit (0.51 µmol L-1) than GCE, CNTs/GCE or some of recently reported nanomaterials-based electrochemical vitamin C biosensors. Especially, the vitamin C concentration in real samples of commercial beverage, vitamin C injection and commercial juice can be determined by the proposed N-GMNs/GCE with satisfied results. Therefore, the utilization of okara as the raw material for the synthesis of nanostructured carbon of N-GMNs is a green method to fabricate an advanced and low-cost electrode material for developing the nonenzymatic electrochemical biosensor for vitamin C detection.

Cobalt sulfides/carbon nanohybrids: a novel biocatalyst for nonenzymatic glucose biofuel cells and biosensors.

Exploring high-performance electrocatalysts is of great importance in developing nonenzymatic biofuel cells. Hybrid nanostructures with transition metal compounds and carbon nanomaterials exhibit excellent electrocatalytic activity and have emerged as promising low-cost alternatives for various electrochemical reactions. Herein, we report cobalt sulfide/carbon nanohybrids via a facile synthesis, which have excellent electrocatalytic activity for glucose oxidation and oxygen reduction reaction. The nonenzymatic glucose biofuel cells equipped with cobalt sulfide/carbon nanohybrids deliver a high open circuit voltage of 0.72 V with a maximum open power density of 88 µW cm-2, indicating that cobalt sulfide/carbon nanohybrids are high performance biocatalysts for bioenergy conversion.

A novel three-dimensional carbonized PANI1600@CNTs network for enhanced enzymatic biofuel cell.

A novel three-dimensional (3D) carbon composite of PANI1600@CNTs with rhizobium-like structure is prepared by in-situ polymerization of aniline monomers around and along the functionalized carbon nanotubes (CNTs) and then carbonized at 1600°C for enzymatic biofuel cells (EBFCs). The SEM and TEM images clearly show that the carbonized PANI grew seamlessly on the surface of CNTs and presented the rhizobium-like structure. The carbonized PANI acts like conductive "glue" and connects the adjacent tubes together, which can assemble the CNTs into a 3D network. The PANI1600@CNTs composite modified glassy carbon electrodes based on glucose oxidase (GOx) and laccase (Lac) exhibit high electrochemical performance. A glucose//O2 EBFC constitutes of the fabricated anode and cathode performs a maximum power density of 1.12mWcm-2 at 0.45V. Furthermore, three of the fabricated EBFCs in series are able to lightening up a yellow light-emitting diode (LED) whose turn-on voltage is about at 1.8V. This work may be helpful for exploiting novel substrates by carbonizing the composites of conducting polymer with nano materials at high-temperature for immobilization of enzymes in the EBFCs or biosensor fields.

Hollow mesoporous CuCo2O4 microspheres derived from metal organic framework: A novel functional materials for simultaneous H2O2 biosensing and glucose biofuel cell.

Hollow mesoporous CuCo2O4 (meso-CuCo2O4) microspheres were successfully synthesized by decomposing metal-organic frameworks (MOFs) as the template. The as-prepared CuCo2O4 microspheres were first simultaneously used for H2O2 biosensing and glucose biofuel cell (GFC) as the enzyme mimic. The resulting of meso-CuCo2O4 displayed not only excellent catalytic performances to H2O2 including a super-fast response time (within 2s), a super-high sensitivity (654.23 µA mM-1 cm-2) and a super-low detection limit (3nM at S/N = 3) on the sensor, but also great values in GFC as anode material with an open circuit voltage of 0.85V, a maximum power density of 0.33 mWcm-2 and a limiting current density of 1.27 mAcm-2, respectively. The preeminent catalytic abilities to H2O2 and glucose may be attributed to the surpassing intrinsic catalytic activity of CuCo2O4 and large specific area of mesoporous structure. These significant findings deriving from this work not only provided a novel exploration for the fabrication of hollow spherical mesoporous bimetallic oxides, but also promoted the development of the supersensitive detection of H2O2 and non-enzymatic biofuel cell.

Graphene oxide-supported carbon nanofiber-like network derived from polyaniline: A novel composite for enhanced glucose oxidase bioelectrode performance.

A three-dimensional architecture of PANI@GO hybrid was synthesized via in-situ polymerization of aniline monomers on the surface of graphene oxide (GO) and carbonized at 1600°C. The SEM images showed that surfaces of planar GO were covered by a compact nanofiber-like polyaniline (PANI) layer which presented an interconnected network. Nanofiber-like PANI on the GO surface was mostly preserved and became the carbon nanofibers (CNFs) after carbonization. The TEM images showed that the carbonized PANI grew seamlessly on the GO surface and served as conductive "network" between interlayers of GO. The carbonized PANI@GO hybrid was used to modify a glassy carbon electrode (GCE) based on GOx, resulting in efficient direct electron transfer (DET) and excellent bio-catalytic performance. In addition, a glucose/O2 fuel cell constructed using Nafion/GOx/PANI1600@GO/GCE as the anode and an E-TEK Pt/C modified GCE as the cathode generated a maximum power density of 0.756mWcm-2 at 0.42V. Findings in this study may be helpful for exploiting novel materials for immobilization of enzymes through carbonizing conducting polymers or their composites with inorganic materials at high temperature for applications in enzymatic biofuel cells or biosensors.

Three-dimensional Co3O4@MWNTs nanocomposite with enhanced electrochemical performance for nonenzymatic glucose biosensors and biofuel cells.

Three-dimensional nanoarchitectures of Co3O4@multi-walled carbon nanotubes (Co3O4@MWNTs) were synthesized via a one-step process with hydrothermal growth of Co3O4 nanoparticles onto MWNTs. The structure and morphology of the Co3O4@MWNTs were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller, scanning electron microscopy and transmission electron microscopy. The electrocatalytic mechanism of the Co3O4@MWNTs was studied by X-ray photoelectron spectroscopy and cyclic voltammetry. Co3O4@MWNTs exhibited high electrocatalytic activity towards glucose oxidation in alkaline medium and could be used in nonenzymatic electrochemical devices for glucose oxidation. The open circuit voltage of the nonenzymatic glucose/O2 fuel cell was 0.68 V, with a maximum power density of 0.22 mW cm-2 at 0.30 V. The excellent electrochemical properties, low cost, and facile preparation of Co3O4@MWNTs demonstrate the potential of strongly coupled oxide/nanocarbon hybrid as effective electrocatalyst in glucose fuel cells and biosensors.

Hexagonal NiS nanobelts as advanced cathode materials for rechargeable Al-ion batteries.

Hexagonal NiS nanobelts served as novel cathode materials for rechargeable Al-ion batteries based on an AlCl3/[EMIm]Cl ionic liquid electrolyte system. The nano-banded structure of the materials can facilitate the electrolyte immersion and enhance Al(3+) diffusion. The hexagonal NiS nanobelt based cathodes exhibit high storage capacity, good cyclability and low overpotential.

Effects and mechanisms of a microcurrent dressing on skin wound healing: a review.

The variety of wound types has resulted in a wide range of wound dressings, with new products frequently being introduced to target different aspects of the wound healing process. The ideal wound dressing should achieve rapid healing at a reasonable cost, with minimal inconvenience to the patient. Microcurrent dressing, a novel wound dressing with inherent electric activity, can generate low-level microcurrents at the device-wound contact surface in the presence of moisture and can provide an advanced wound healing solution for managing wounds. This article offers a review of the effects and mechanisms of the microcurrent dressing on the healing of skin wounds.