Operando Spectroscopic Elucidation of the Bubble Sunshade Effect in Inorganic-Biological Hybrids for Photosynthetic Hydrogen Production.

Hydrogen production by photosynthetic hybrid systems (PBSs) offers a promising avenue for renewable energy. However, the light-harvesting efficiency of PBSs remains constrained due to unclear intracellular kinetic factors. Here, we present an operando elucidation of the sluggish light-harvesting behavior for existing PBSs and strategies to circumvent them. By quantifying the spectral shift in the structural color scattering of individual PBSs during the photosynthetic process, we observe the accumulation of product hydrogen bubbles on their outer membrane. These bubbles act as a sunshade and inhibit light absorption. This phenomenon elucidates the intrinsic constraints on the light-harvesting efficiency of PBSs. The introduction of a tension eliminator into the PBSs effectively improves the bubble sunshade effect and results in a 4.5-fold increase in the light-harvesting efficiency. This work provides valuable insights into the dynamics of transmembrane transport gas products and holds the potential to inspire innovative designs for improving the light-harvesting efficiency of PBSs.

Reversible Regulation of Long-Distance Charge Transport in DNA Nanowires by Dynamically Controlling Steric Conformation.

Understanding of DNA-mediated charge transport (CT) is significant for exploring circuits at the molecular scale. However, the fabrication of robust DNA wires remains challenging due to the persistence length and natural flexibility of DNA molecules. Moreover, CT regulation in DNA wires often relies on predesigned sequences, which limit their application and scalability. Here, we addressed these issues by preparing self-assembled DNA nanowires with lengths of 30-120 nm using structural DNA nanotechnology. We employed these nanowires to plug individual gold nanoparticles into a circuit and measured the transport current in nanowires with an optical imaging technique. Contrary to the reported cases with shallow or no length dependence, a fair current attenuation was observed with increasing nanowire length, which experimentally confirmed the prediction of the incoherent hopping model. We also reported a mechanism for the reversible CT regulation in DNA nanowires, which involves dynamic transitions in the steric conformation.

Advances in self-assembled Au-DNA nanomachines.

Au-DNA self-assembled nanomachines can perform intelligent tasks such as sensing biomarkers and delivery of drug molecules through rational customization and programming. By virtue of their efficient signal amplification and flexible scalability, Au-DNA nanomachines have developed into one of the most promising nanodevices. In this review, we summarize the latest progress in Au-DNA self-assembled nanomachines for biosensing applications. First, the functional modules for building Au-DNA nanomachines are introduced. Subsequently, we summarize the biosensing applications of Au-DNA nanomachines with electrochemical or fluorescent signals as the output, respectively. Finally, we discuss the challenges and potential opportunities for Au-DNA nanomachines in biomedical applications.

Antibacterial Carbon Dots-Based Composites.

The emergence and global spread of bacterial resistance to conventionally used antibiotics have highlighted the urgent need for new antimicrobial agents that might replace antibiotics. Currently, nanomaterials hold considerable promise as antimicrobial agents in anti-inflammatory therapy. Due to their distinctive functional physicochemical characteristics and exceptional biocompatibility, carbon dots (CDs)-based composites have attracted a lot of attention in the context of these antimicrobial nanomaterials. Here, a thorough assessment of current developments in the field of antimicrobial CDs-based composites is provided, starting with a brief explanation of the general synthesis procedures, categorization, and physicochemical characteristics of CDs-based composites. The many processes driving the antibacterial action of these composites are then thoroughly described, including physical destruction, oxidative stress, and the incorporation of antimicrobial agents. Finally, the obstacles that CDs-based composites now suffer in combating infectious diseases are outlined and investigated, along with the potential applications of antimicrobial CDs-based composites.

Surface passivation of intensely luminescent all-inorganic nanocrystals and their direct optical patterning.

All-inorganic nanocrystals (NCs) are of great importance in a range of electronic devices. However, current all-inorganic NCs suffer from limitations in their optical properties, such as low fluorescence efficiencies. Here, we develop a general surface treatment strategy to obtain intensely luminescent all-inorganic NCs (ILANs) by using designed metal salts with noncoordinating anions that play a dual role in the surface treatment process: (i) removing the original organic ligands and (ii) binding to unpassivated Lewis basic sites to preserve the photoluminescent (PL) properties of the NCs. The absolute photoluminescence quantum yields (PLQYs) of red-emitting CdSe/ZnS NCs, green-emitting CdSe/CdZnSeS/ZnS NCs and blue-emitting CdZnS/ZnS NCs in polar solvents are 97%, 80% and 72%, respectively. Further study reveals that the passivated Lewis basic sites of ILANs by metal cations boost the efficiency of radiative recombination of electron-hole pairs. While the passivation of Lewis basic sites leads to a high PLQY of ILANs, the exposed Lewis acidic sites provide the possibility for in situ tuning of the functions of NCs, creating opportunities for direct optical patterning of functional NCs with high resolution.

A Telomerase-Assisted Strategy for Regeneration of DNA Nanomachines in Living Cells.

DNA nanomachines have been engineered into diverse personalized devices for diagnostic imaging of biomarkers; however, the regeneration of DNA nanomachines in living cells remains challenging. Here, we report an ingenious DNA nanomachine that can implement telomerase (TE)-activated regeneration in living cells. Upon apurinic/apyrimidinic endonuclease 1 (APE1)-responsive initiation of the nanomachine, the walker of the nanomachine moves along tracks regenerated by TE, generating multiply amplified signals through which APE1 can be imaged in situ. Additionally, augmentation of the signal due to the regeneration of the nanomachines could reveal differential expression of TE in different cell lines. To the best of our knowledge, this is the first proof-of-concept demonstration of the use of biomarkers to assist in the regeneration of nanomachines in living cells. This study offers a new paradigm for the development of more applicable and efficient DNA nanomachines.

General Synergistic Hybrid Catalyst Synthesis Method Using a Natural Enzyme Scaffold-Confined Metal Nanocluster.

Due to differences in the chemical properties or optimal reaction conditions of the catalysts, the challenge in the design of bio-chemical hybrid catalysts is that the bio-catalysts or chemical catalysts usually cannot maintain the initial catalytic performance. Herein, we report a general bio-chemical hybrid catalyst synthesis method using a natural enzyme scaffold-confined metal nanocluster. A redox-active enzyme is a nanoreactor that allows access to and reduces metal ions into metal nanoclusters in situ, resulting in the enzyme-confined metal nanocluster hybrid catalyst with a synergistic effect to boost catalytic performance. Specifically, bilirubin oxidase-Ir nanoclusters (BOD-Ir NCs) with catalytic properties for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are designed. The BOD-Ir NCs exhibit an approximately 2-fold ORR activity compared with pure BOD and a 4-fold OER activity compared with pure Ir NCs. BOD-Ir NCs exhibit stability for over 50,000 s, exceeding that of pure Ir NCs (22,000 s). The synergistic catalytic performance is attributed to the following: the mild preparation condition and matched sizes of BOD and the Ir NCs maintain the natural activity of BOD; the highly conductive Ir NCs improve the ORR activity of BOD; and the confining effect of BOD, which improves the stability and activity of the Ir NCs during the OER. In particular, BOD-Ir NCs exhibit a high half-wave potential of 0.97 V for the ORR and a low overpotential of 319 mV at 10 mA cm-2 for the OER, surpassing most of reported catalysts under neutral conditions. Furthermore, laccase-Ir NCs and glucose oxidase-Pd NCs with synergistic catalytic performances are fabricated, proving the universality of this synthetic method. This facile strategy for designing synergistic hybrid catalysts is expected to be applied to more complex chemical transformations.

Plasmonic Probing Single-Cell Bio-Current Waves with a Shrinking Magnetite Nanoprobe.

Probing of the single-cell level extracellular electron transfer highlights the maximum output current for microbial fuel cells (MFCs) at hundreds of femtoampere per cell, which is difficult to achieve by existing devices. Past studies focus on the external factors for boosting charge-extraction efficiency from bacteria. Here, we elucidate the intracellular factors that determine this output limit by monitoring the respiratory-driven shrinking kinetics of a single magnetite nanoprobe immobilized on a single Shewanella oneidensis MR-1 cell with plasmonic imaging. Quantified dissolving of nanoprobes unveils a previously undescribed bio-current fluctuation between 0 and 2.7 fA on a ∼40 min cycle. Simultaneously tracing of endogenous oscillations indicates that the bio-current waves are correlated with the periodic cellular electrokinesis. The unsynchronized electron transfer capability in the cell population results in the mean current of 0.24 fA per cell, significantly smaller than in single cells. It explains why the averaged output current of MFCs cannot reach the measured single-cell currents. This work offers a different perspective to improve the power output by extending the active episodes of the bio-current waves.

A self-powered and drug-free diabetic wound healing patch breaking hyperglycemia and low H2O2 limitations and precisely sterilizing driven by electricity.

Accelerating diabetes-related chronic wound healing is a long-sought-after goal in diabetes management. However, therapeutic strategies based on antibiotics or catalysts still face great challenges to break the limitations of antimicrobial resistance, low H2O2 and the blocking effect of bacterial biofilms on antibiotic/catalyst penetration. Herein, we reported a glucose biofuel cell-powered and drug-free antibacterial patch, which consisted of an MAF-7 protected glucose oxidase/horseradish peroxidase anode and a horseradish peroxidase cathode, for treating diabetic wounds. This self-powered patch could take high blood glucose as fuel to generate electricity and abundant reactive oxygen species (ROS) in situ, synergistically regulating local hyperglycemia and breaking the limitations of insufficient ROS caused by low H2O2 levels. In particular, the electric field created by the GBFC could drive the negatively charged bacteria to adhere firmly to the electrode surface. As a result, the ROS produced in situ on the electrodes was localized to the bacteria, realizing precise sterilization. In vivo experiments confirmed that this self-powered patch enabled the wounds on diabetic mice to take a mere 10 days to eliminate inflammation and form mature skin with new hair follicles, demonstrating its great potential in treating bacteria-infected diabetic wounds.

Hierarchical S-modified Cu porous nanoflakes for efficient CO2 electroreduction to formate.

Electrochemical reduction of CO2 into liquid fuels is a promising approach to achieving a carbon-neutral energy cycle but remains a great challenge due to the lack of efficient catalysts. Here, the hierarchical architectures assembled by ultrathin and porous S-modified Cu nanoflakes (Cu-S NFs) are designed and constructed as an efficient electrocatalyst for CO2 conversion to formate with high partial current density. Specifically, when integrated into a gas diffusion electrode in a flow cell, Cu-S NFs are capable of delivering the ultrahigh formate current density up to 404.1 mA cm-2 with a selectivity of 89.8%. Electrochemical tests and theoretical calculations indicate that the superior performance of the designed catalysts may be attributed to the unique structure, which can provide abundant active sites, fast charge transfer, and highly active edge sites.

Nanomaterials Facilitating Conversion Efficiency Strategies for Microbial CO2 Reduction.

Microbial electro- and photoelectrochemical CO2 reduction represents an opportunity to tackle the environmental demand for sustainable fuel production. Nanomaterials critically impact the electricity- and solar-driven microbial CO2 reduction processes. This minireview comprehensively summarizes the recent developments in the configuration and design of nanomaterials for enhancement of the bacterial adhesion and extracellular electron transfer (EET) processes, based on the modification technologies of improving chemical stability, electrochemical conductivity, biocompatibility, and surface area. Furthermore, the investigation of incorporating non-photosynthetic microorganisms using advanced light-harvesting nanostructured photoelectrodes for solar-to-chemical conversion, as well as the current understanding of EET mechanisms occurring at photosynthetic semiconductor nanomaterials-bacteria biohybrid interface is detailed. The crucial factors influencing the performance of microbial CO2 reduction systems and future perspectives are discussed to provide guidance for the realization of their large-scale application.

In situ formed N-containing copper nanoparticles: a high-performance catalyst toward carbon monoxide electroreduction to multicarbon products with high faradaic efficiency and current density.

Developing efficient catalysts for electrochemical carbon monoxide reduction (ECOR) with high faradaic efficiency (FE) and current density is highly desirable. In this work, we demonstrate that the N-containing Cu nanoparticles formed in situ by the reconstruction of cuprous 7,7,8,8-tetracyanoquinodimethane possess high-performance ECOR ability. Impressively, the N-containing Cu nanoparticle catalyst presented the highest FE of 81.31% towards multicarbon products with a high commercial-grade partial current density of 162.62 mA cm-2, which is among the best of the reported Cu-based ECOR catalysts at -0.69 V versus the reversible hydrogen electrode. The retained ligand on the formed catalyst via the convenient in situ formation is crucial for the selectivity of multicarbon products. This work will arouse enthusiasm for the utilization of reconstruction features for designing ligand-containing catalysts with enhanced artificial carbon fixation ability.

Damage-Free and Time-Saving Platform Integrated by a Flow Membrane Separation Device and a Dual-Target Biofuel Cell-Based Biosensor for Continuous Sorting and Detection of Exosomes and Host Cells in Human Serum.

The growth relationship between exosomes (EXOs) and the host cells is highly desired for tumor evaluations, which puts forward high demand on the accurate and convenient acquisition of their individual quantitative information. However, the tedious and destructive separation process and the requirement of dual-channel detection make it become an extremely challenging task. Herein, we integrated an enzymatic biofuel cell (EBFC)-powered biosensor with a flow cell-supported membrane separation device (FMSC) to develop a continuous separation and detection platform for EXOs and host cancer cells in human serum. The FMSC equipped with an aluminum oxide membrane served as a size-dependent sorting unit to nondestructively extract EXOs from human serum within 5 min, representing a 99.3% reduction in isolating time compared to ultracentrifugation. The EBFC-powered biosensors modified with different aptamers on anodes and cathodes were used as a dual-channel sensing unit. By regulating the controlling valves of different fluid passages, the extracted EXOs and residual host cells could be successively inputted into EBFC-powered biosensors, which generated a segmental degradation in output performance due to the EXO-and host cell-caused increase in the steric hindrance of anodes and cathodes, respectively. Based on these degradations, we obtained the quantitative information of EXOs and host cells with a record-breaking sensitivity (EXOs: 5.59 × 103 particles/mL and host cells: 25 cells/mL). Moreover, the growth relationship between EXOs and host cells was also built, which would be beneficial for the disclosure of the growth state or even more detailed biology information of tumor.

Multistage Photoactivatable Zinc-Responsive Nanodevices for Monitoring and Regulating Dysfunctional Islet ß-Cells.

The dysfunctional islet ß-cell triggered by excessive deposition of Zn2+ constituted a striking indicator of the occurrence of diabetic disease. However, it remained a formidable challenge to reflect the real-time function of ß-cell by monitoring the Zn2+ content. Herein, multistage photoactivatable Zn2+-responsive nanodevice (denoted as AD2@USD1) was presented for sensing, regulating, and evaluating Zn2+ levels in dysfunctional islet ß-cells. The photoactivated signatures on the satellite shell layer of the nanodevices and the internally loaded chelating factors effectively identified and intervened in the real-time concentration of Zn2+, the photothermal feedback component decorated on the inner core permitted the assessment of the post-intervention Zn2+ levels, achieving an integrated intervention and prognostic assessment in response to the abnormal islet ß-cell function induced by Zn2+ deposition. In this way, one strategy for sensing and regulating islet ß-cell function-oriented to Zn2+ was established. Our study introduced AD2@USD1 as a tool for effectively sensing, adjusting, and assessing the Zn2+ level in islet ß-cells with abnormalities, gaining a potential breakthrough in the treatment of diabetes.

Enhanced transmembrane electron transfer in Shewanella oneidensis MR-1 using gold nanoparticles for high-performance microbial fuel cells.

Low efficiency of extracellular electron transfer (EET) is a major bottleneck in developing high-performance microbial fuel cells (MFCs). Herein, we construct Shewanella oneidensis MR-1@Au for the bioanode of MFCs. Through performance recovery experiments of mutants, we proved that abundant Au nanoparticles not only tightly covered the bacteria surface, but were also distributed in the periplasm and cytoplasm, and even embedded in the outer and inner membranes of the cell. These Au nanoparticles could act as electron conduits to enable highly efficient electron transfer between S. oneidensis MR-1 and electrodes. Strikingly, the maximum power density of the S. oneidensis MR-1@Au bioanode reached up to 3749 mW m-2, which was 17.4 times higher than that with the native bacteria, reaching the highest performance yet reported in MFCs using Au or Au-based nanocomposites as the anode. This work elucidates the role of Au nanoparticles in promoting transmembrane and extracellular electron transfer from the perspective of molecular biology and electrochemistry, while alleviating bottlenecks in MFC performances.

CRISPR System-Linked Self-Assembling Nanoplatforms for Inspection and Screening of Gastric Cancer Stem Cells.

Cancer stem cells (CSCs) possess a high degree of plasticity, constituting a formidable challenge to identify and screen CSCs in situ with outstanding specificity and sensitivity. To overcome this limitation, a self-assembled heterodimer consisting of clustered regularly interspaced short palindromic repeats/Cas12a (named A-CCA) linkage is designed for in situ identification and screening of gastric CSCs (GCSCs) from gastric cancer cells (GCCs). In this system, the editable character of crRNA performs recognition of dual-targets in GCSCs, effectively boosting the specificity of identification, while the enzymatic reaction of Cas12a contributes meaningfully to the sensitivity of sensing, enabling in situ examination and screening of GCSCs. Specifically, the A-CCA nanoplatforms hybridized with ABCG 2 and ABCB 1 overexpress in GCSCs, which can generate heterodimers and simultaneously restore the function of trans-cleavage. At this time, the asymmetry of the heterodimer causes a circular dichroism signal, which together with the recovered fluorescence signal form a dual-signals output system that can further ensure the precision of screening GCSC. Therefore, fluorescence-enhanced GCSCs can be sorted out from GCCs by flow cytometry. Furthermore, GCSCs screened by this assay possess extremely aggressive tumorigenic efficiency, providing a fundamental research object for further developing CSC targeted drugs in vivo.

Effectiveness of smart health-based rehabilitation on patients with poststroke dysphagia: A brief research report.

Objective: This study aimed to evaluate the effectiveness of smart health-based rehabilitation on patients with poststroke dysphagia (PSD). Methods: We recruited 60 PSD patients and randomly allocated them to the intervention (n = 30) and control (n = 30) groups. The former received the smart health-based rehabilitation for 12 weeks, whereas the latter received routine rehabilitation. Water swallow test (WST), standardized swallowing assessment (SSA), swallow quality-of-life questionnaire (SWAL-QOL), stroke self-efficacy questionnaire (SSEQ), perceived social support scale (PSSS) and nutritional measurements including body weight, triceps skinfold thickness (TSF), total protein (TP), serum albumin (ALB) and serum prealbumin (PA) in both groups were measured. Results: When the baseline WST, SSA, SWAL-QOL, SSEQ, PSSS and nutritional measurements were examined, there was no significant difference between the intervention group and the control group (P > 0.05). After rehabilitation interventions, the WST and SSA scores in the intervention group were significantly lower than those in the control group (P < 0.01). The SWAL-QOL, SSEQ and PSSS scores in the intervention group were significantly higher than in the control group (P < 0.01). Compared with the control group, the intervention group showed an increase in the serum levels of PA (P < 0.01). However, no statistically significant difference existed between the intervention group and the control group in terms of body weight, TSF, TP or ALB (P > 0.05). Conclusions: Overall, our data revealed that smart health-based rehabilitation is significantly beneficial to the swallowing function, quality of life, self-efficacy, and social support for PSD patients when compared with routine rehabilitation. However, nutritional measurements were not significantly improved in such patients under the smart health-based rehabilitation when compared the routine rehabilitation. In the future, it is necessary to extend the intervention time to further evaluate the long-term efficacy of smart health-based rehabilitation on nutritional measurements of PSD patients.

Self-assembled nanomaterials for biosensing and therapeutics: recent advances and challenges.

Self-assembled nanomaterials (SANs) exhibit designable biofunctions owing to their tunable nanostructures and modifiable surface. Various constituent units and multi-dimensional structures of SANs provide unlimited possibilities for numerous applications. This review emphasizes the recent development of SANs in the fields of biosensing, bioimaging, and nano-drug engineering. The unit type, design concepts, material advantages, assembly driving force, nanostructure effects, drug loading performance, etc. are discussed and summarized. Finally, we briefly summarize how to assemble unique nanomaterials and point out the key challenges in this field.

Catalytic route electrochemiluminescence microscopy of cell membranes with nitrogen-doped carbon dots as nano-coreactants.

Catalytic route electrochemiluminescence (ECL) microscopy enables imaging upper cell membranes with freely diffusing Ru(bpy)32+ as the emitter and nitrogen-doped carbon dots as the nano-coreactants and labels. This strategy provides a vertical resolution when studying the ECL profiles at different heights and realizes the ECL imaging of the externalized phosphatidylserine.

Layer-by-layer assembly of Au and CdS nanoparticles on the surface of bacterial cells for photo-assisted bioanodes in microbial fuel cells.

Surface modification of exoelectrogens with photoelectric materials is a promising way for achieving photo-assisted microbial fuel cells (MFCs). However, the poor conductivity of most photoelectric materials inevitably hampers the electron transfer inside bacterial biofilms. Herein, by utilizing the electrostatic layer-by-layer assembly strategy, the conductive Au nanoparticles (NPs) and photo-responsive CdS NPs were alternatively modified onto the surface of Escherichia coli for photo-assisted bioanodes in MFCs. The CdS layer was found to protect the bacterial cells from light illumination-induced inactivation. When the CdS layer coexisted with an outer layer of Au NPs, the modification of the CdS layers can generate photocurrent without any loss of biocurrent, because the outer Au layer could serve as a conductive channel for the photoelectron and bioelectron transfer between each bacterium. But the increase of CdS layers failed to further improve the photocurrent, implying that the light was inaccessible to the inner CdS layer. This work brings a universal way to fabricate conductive and photo-responsive bacteria, which would deepen the application of cell-surface modification technology in photo-assisted MFCs.