Nanotransistor-based gas sensing with record-high sensitivity enabled by electron trapping effect in nanoparticles.

Highly sensitive, low-power, and chip-scale H2 gas sensors are of great interest to both academia and industry. Field-effect transistors (FETs) functionalized with Pd nanoparticles (PdNPs) have recently emerged as promising candidates for such H2 sensors. However, their sensitivity is limited by weak capacitive coupling between PdNPs and the FET channel. Herein we report a nanoscale FET gas sensor, where electrons can tunnel between the channel and PdNPs and thus equilibrate them. Gas reaction with PdNPs perturbs the equilibrium, and therefore triggers electron transfer between the channel and PdNPs via trapping or de-trapping with the PdNPs to form a new balance. This direct communication between the gas reaction and the channel enables the most efficient signal transduction. Record-high responses to 1-1000 ppm H2 at room temperature with detection limit in the low ppb regime and ultra-low power consumption of ~ 300 nW are demonstrated. The same mechanism could potentially be used for ultrasensitive detection of other gases. Our results present a supersensitive FET gas sensor based on electron trapping effect in nanoparticles.

The Molecular Profile of Soil Microbial Communities Inhabiting a Cambrian Host Rock.

The process of soil genesis unfolds as pioneering microbial communities colonize mineral substrates, enriching them with biomolecules released from bedrock. The resultant intricate surface units emerge from a complex interplay among microbiota and plant communities. Under these conditions, host rocks undergo initial weathering through microbial activity, rendering them far from pristine and challenging the quest for biomarkers in ancient sedimentary rocks. In addressing this challenge, a comprehensive analysis utilizing Gas Chromatography Mass Spectrometry (GC-MS) and Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) was conducted on a 520-Ma-old Cambrian rock. This investigation revealed a diverse molecular assemblage with comprising alkanols, sterols, fatty acids, glycerolipids, wax esters, and nitrogen-bearing compounds. Notably, elevated levels of bacterial C16, C18 and C14 fatty acids, iso and anteiso methyl-branched fatty acids, as well as fungal sterols, long-chained fatty acids, and alcohols, consistently align with a consortium of bacteria and fungi accessing complex organic matter within a soil-type ecosystem. The prominence of bacterial and fungal lipids alongside maturity indicators denotes derivation from heterotrophic activity rather than ancient preservation or marine sources. Moreover, the identification of long-chain (>C22) n-alkanols, even-carbon-numbered long chain (>C20) fatty acids, and campesterol, as well as stigmastanol, provides confirmation of plant residue inputs. Furthermore, findings highlight the ability of contemporary soil microbiota to inhabit rocky substrates actively, requiring strict contamination controls when evaluating ancient molecular biosignatures or extraterrestrial materials collected.

Safety and efficacy of indocyanine green fluorescence imaging for real-time guidance of laparoscopic thermal ablation in patients with liver cancer.

PURPOSE: To evaluate the safety and efficacy of indocyanine green fluorescence imaging for real-time guidance of laparoscopic thermal ablation in patients with liver cancer. MATERIALS AND METHODS: A total of 27 patients with 40 liver lesions underwent fluorescence-assisted laparoscopic ablation between January 2020 to March 2023. The sensitivity of indocyanine green (ICG)-fluorescence imaging, technique effectiveness rate and complications of fluorescence-assisted laparoscopic thermal ablation were evaluated. RESULTS: In total, 33 out of the 40 lesions were identified by ICG-fluorescence imaging technique, with the sensitivity of 82.5%. The sensitivity of ICG-fluorescence imaging of tumor detection in liver surface of parenchyma was significantly higher than that in the deeply located hepatic parenchyma (96.8% vs 33.3%, p = 0.002). ICG-fluorescence imaging procedures detected 4 lesions that cannot be seen on intraoperative ultrasound. It provides clear demarcation lines on the hepatic surface. Technical success is achieved if the necrotic zone had at least a 5 mm ablative margin around the outer edge of the ICG-fluorescence image. Technical success of fluorescence laparoscopic radiofrequency ablation (FLRFA) and fluorescence laparoscopic microwave ablation (FLMWA) was 100% (27/27). Technical effectiveness is defined by the complete necrotic lesions of the local tumor tissue during follow-up. According to the CT/MRI one month after FLRFA or FLMWA, the technical efficacy rate was 92.5% (37/40) and local tumor progression occurred in 7.5% (3/40) of the enrolled lesions. During the follow-up period, no major complications were observed. CONCLUSION: ICG-fluorescence imaging guided laparoscopic thermal ablation was feasible, safe and effective.

Effects of Multi-Mechanism Complementary Therapy on Pain and Anxiety During Labor Latency in Primiparous Women.

Objective: Evaluate the efficacy of single and mixed complementary therapies, with different analgesic mechanisms, in relieving pain and anxiety during the late labor period. Design and method: In this study, 145 primiparous women with 2-3 cm dilation of the cervix were randomly assigned to one of five groups: control group (psychological comfort), comprehensive group, aroma group, auricular acupuncture group, and music group. The groups were distributed equally (1:1:1:1 ratio), and pain and anxiety scores were assessed at 30, 60, and 120 minutes post-intervention in each group. Outcomes and measures: Compared to the control group, all intervention groups showed lower pain scores. The comprehensive group had the largest reduction in pain scores at 30, 60, and 120 minutes post-intervention. The auricular point, aroma, and music groups also demonstrated significant reductions in pain scores at different time points. Only the comprehensive group had a statistically significant reduction in anxiety at 30 minutes post-intervention compared to the control group. However, at 60 and 120 minutes post-intervention, all intervention groups showed lower anxiety scores compared to the control group. Conclusion: The optimal effects of each therapy varied in terms of timing and duration. Combination therapy showed a greater effect size than single complementary therapy.

The Emerging Landscape for Combating Resistance Associated with Energy-Based Therapies via Nanomedicine.

Cancer represents a serious disease with significant implications for public health, imposing substantial economic burden and negative societal consequences. Compared to conventional cancer treatments, such as surgery and chemotherapy, energy-based therapies (ET) based on athermal and thermal ablation provide distinct advantages, including minimally invasive procedures and rapid postoperative recovery. Nevertheless, due to the complex pathophysiology of many solid tumors, the therapeutic effectiveness of ET is often limited. Nanotechnology offers unique opportunities by enabling facile material designs, tunable physicochemical properties, and excellent biocompatibility, thereby further augmenting the outcomes of ET. Numerous nanomaterials have demonstrated the ability to overcome intrinsic therapeutic resistance associated with ET, leading to improved antitumor responses. This comprehensive review systematically summarizes the underlying mechanisms of ET-associated resistance (ETR) and highlights representative applications of nanoplatforms used to mitigate ETR. Overall, this review emphasizes the recent advances in the field and presents a detailed account of novel nanomaterial designs in combating ETR, along with efforts aimed at facilitating their clinical translation.

A Booster for Radiofrequency Ablation: Advanced Adjuvant Therapy via In Situ Nanovaccine Synergized with Anti-programmed Death Ligand 1 Immunotherapy for Systemically Constraining Hepatocellular Carcinoma.

Radiofrequency ablation (RFA) is one of the most common minimally invasive techniques for treating hepatocellular carcinoma (HCC), which could destroy tumors through hyperthermia and generate massive tumor-associated antigens (TAAs). However, residual malignant tissues or small satellite lesions are hard to eliminate, generally resulting in metastases and recurrence. Herein, an advanced in situ nanovaccine formed by layered double hydroxides carrying cGAMP (STING agonist) (LDHs-cGAMP) and adsorbed TAAs was designed to potentiate the RFA-induced antitumor immune response. As-prepared LDHs-cGAMP could effectively enter cancerous or immune cells, inducing a stronger type I interferon (IFN-I) response. After further adsorption of TAAs, nanovaccine generated sustained immune stimulation and efficiently promoted activation of dendritic cells (DCs). Notably, infiltrations of cytotoxic lymphocytes (CTLs) and activated DCs in tumor and lymph nodes were significantly enhanced after nanovaccine treatment, which distinctly inhibited primary, distant, and metastasis of liver cancer. Furthermore, such a nanovaccine strategy greatly changed the tumor immune microenvironment and promoted the response efficiency of anti-programmed death ligand 1 (αPD-L1) immunotherapy, significantly arresting the poorly immunogenic hepa1-6 liver cancer progression. These findings demonstrate the potential of nanovaccine as a booster for RFA in liver cancer therapy and provide a promising in situ cancer vaccination strategy.

Ion sensing with single charge resolution using sub-10-nm electrical double layer-gated silicon nanowire transistors.

Electrical sensors have been widely explored for the analysis of chemical/biological species. Ion detection with single charge resolution is the ultimate sensitivity goal of such sensors, which is yet to be experimentally demonstrated. Here, the events of capturing and emitting a single hydrogen ion (H+) at the solid/liquid interface are directly detected using sub­10-nm electrical double layer­gated silicon nanowire field-effect transistors (SiNWFETs). The SiNWFETs are fabricated using a complementary metal-oxide-semiconductor compatible process, with a surface reassembling step to minimize the device noise. An individually activated surface Si dangling bond (DB) acts as the single H+ receptor. Discrete current signals, generated by the single H+-DB interactions via local Coulomb scattering, are directly detected by the SiNWFETs. The single H+-DB interaction kinetics is systematically investigated. Our SiNWFETs demonstrate unprecedented capability for electrical sensing applications, especially for investigating the physics of solid/liquid interfacial interactions at the single charge level.

The Molecular Record of Metabolic Activity in the Subsurface of the Río Tinto Mars Analog.

In the subsurface, the interplay between microbial communities and the surrounding mineral substrate, potentially used as an energy source, results in different mineralized structures. The molecular composition of such structures can record and preserve information about the metabolic pathways that have produced them. To characterize the molecular composition of the subsurface biosphere, we have analyzed some core samples by time-of-flight secondary ion mass spectrometry (ToF-SIMS) that were collected in the borehole BH8 during the operations of the Mars Analog and Technology Experiment (MARTE) project. The molecular analysis at a micron-scale mapped the occurrence of several inorganic complexes bearing PO3-, SOx(2 to 4)-, NOx(2,3)-, FeOx(1,2)-, SiO2-, and Cl-. Their distribution correlates with organic molecules that were tentatively assigned to saturated and monounsaturated fatty acids, polyunsaturated fatty acids, saccharides, phospholipids, sphingolipids, and potential peptide fragments. SOx- appear to be mineralizing some microstructures larger than 25 microns, which have branched morphologies, and that source SO3-bearing adducts. PO3-rich compounds occur in two different groups of microstructures which size, morphology, and composition are different. While a group of >40-micron sized circular micronodules lacks organic compounds, an ovoidal microstructure is associated with m/z of other lipids. The NO2-/NO3- and Cl- ions occur as small microstructure clusters (<20 microns), but their distribution is dissimilar to the mineralized microstructures bearing PO3-, and SO3-. However, they have a higher density in areas with more significant enrichment in iron oxides that are traced by different Fe-bearing anions like FeO2-. The distribution of the organic and inorganic negative ions, which we suggest, resulted from the preservation of at least three microbial consortia (PO4--, and NO2--/NO3--mineralizers PO4-lipid bearing microstructures), would have resulted from different metabolic and preservation pathways.

Redox Buffering Effects in Potentiometric Detection of DNA Using Thiol-Modified Gold Electrodes.

Label-free potentiometric detection of DNA molecules using a field-effect transistor (FET) with a gold gate offers an electrical sensing platform for rapid, straightforward, and inexpensive analyses of nucleic acid samples. To induce DNA hybridization on the FET sensor surface to enable potentiometric detection, probe DNA that is complementary to the target DNA has to be immobilized on the FET gate surface. A common method for probe DNA functionalization is based on thiol-gold chemistry, immobilizing thiol-modified probe DNA on a gold gate with thiol-gold bonds. A self-assembled monolayer (SAM), based on the same thiol-gold chemistry, is also needed to passivate the rest of the gold gate surface to prevent non-specific adsorption and to enable favorable steric configuration of the probe DNA. Herein, the applicability of such FET-based potentiometric DNA sensing was carefully investigated, using a silicon nanoribbon FET with a gold-sensing gate modified with thiol-gold chemistry. We discover that the potential of the gold-sensing electrode is determined by the mixed potential of the gold-thiol and gold-oxygen redox interactions. This mixed potential gives rise to a redox buffer effect which buffers the change in the surface charge induced by the DNA hybridization, thus suppressing the potentiometric signal. Analogous redox buffer effects may also be present for other types of potentiometric detections of biomarkers based on thiol-gold chemistry.

Characterization of Sulfurimonas hydrogeniphila sp. nov., a Novel Bacterium Predominant in Deep-Sea Hydrothermal Vents and Comparative Genomic Analyses of the Genus Sulfurimonas.

Bacteria of the genus Sulfurimonas within the class Campylobacteria are predominant in global deep-sea hydrothermal environments and widespread in global oceans. However, only few bacteria of this group have been isolated, and their adaptations for these extreme environments remain poorly understood. Here, we report a novel mesophilic, hydrogen- and sulfur-oxidizing bacterium, strain NW10T, isolated from a deep-sea sulfide chimney of Northwest Indian Ocean.16S rRNA gene sequence analysis showed that strain NW10T was most closely related to the vent species Sulfurimonas paralvinellae GO25T with 95.8% similarity, but ANI and DDH values between two strains were only 19.20 and 24.70%, respectively, indicating that strain NW10 represents a novel species. Phenotypic characterization showed strain NW10T is an obligate chemolithoautotroph utilizing thiosulfate, sulfide, elemental sulfur, or molecular hydrogen as energy sources, and molecular oxygen, nitrate, or elemental sulfur as electron acceptors. Moreover, hydrogen supported a better growth than reduced sulfur compounds. During thiosulfate oxidation, the strain can produce extracellular sulfur of elemental α-S8 with an unknown mechanism. Polyphasic taxonomy results support that strain NW10T represents a novel species of the genus Sulfurimonas, and named as Sulfurimonas hydrogeniphila sp. nov. Genome analyses revealed its diverse energy metabolisms driving carbon fixation via rTCA cycling, including pathways of sulfur/hydrogen oxidation, coupled oxygen/sulfur respiration and denitrification. Comparative analysis of the 11 available genomes from Sulfurimonas species revealed that vent bacteria, compared to marine non-vent strains, possess unique genes encoding Type V Sqr, Group II, and Coo hydrogenase, and are selectively enriched in genes related to signal transduction and inorganic ion transporters. These phenotypic and genotypic features of vent Sulfurimonas may explain their thriving in hydrothermal environments and help to understand the ecological role of Sulfurimonas bacteria in hydrothermal ecosystems.

Sulfurimonas indica sp. nov., a hydrogen- and sulfur-oxidizing chemolithoautotroph isolated from a hydrothermal sulfide chimney in the Northwest Indian Ocean.

A novel mesophilic, hydrogen- and sulfur-oxidizing bacterium, designated strain NW8NT, was collected from a sulfide chimney at the deep-sea hydrothermal vent on the Carlsberg Ridge of the Northwest Indian Ocean. The cells were Gram-stain-negative, motile, short rods with a single polar flagellum. The temperature, pH and salinity ranges for growth of strain NW8NT were 4-40 °C (optimum, 33 °C), pH 4.5-7.5 (optimum, pH 5.5) and 340-680 mM NaCl (optimum, 510 mM). The isolate was an obligate chemolithoautotroph capable of growth using hydrogen, thiosulfate, sulfide or elemental sulphur as the sole energy source, carbon dioxide as the sole carbon source and molecular oxygen as the sole electron acceptor. The major cellular fatty acids of strain NW8NT were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), C16 : 0 and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The total size of its genome was 2 093 492 bp and the genomic DNA G+C content was 36.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences and core genes showed that the novel isolate belonged to the genus Sulfurimonas and was most closely related to Sulfurimonas paralvinellae GO25T (97.4 % sequence identity). The average nucleotide identity and DNA-DNAhybridization values between strain NW8NT and S. paralvinellae GO25T was 77.8 and 21.1 %, respectively. Based on the phylogenetic, genomic and phenotypic data presented here, strain NW8NT represents a novel species of the genus Sulfurimonas, for which the name Sulfurimonas indica sp. nov. is proposed, with the type strain NW8NT (=MCCC 1A13988T=KTCC 15780T).

Elemental sulfur reduction by a deep-sea hydrothermal vent Campylobacterium Sulfurimonas sp. NW10.

Sulfurimonas species (class Campylobacteria, phylum Campylobacterota) were globally distributed and especially predominant in deep-sea hydrothermal environments. They were previously identified as chemolithoautotrophic sulfur-oxidizing bacteria (SOB), whereas little is known about their potential in sulfur reduction. In this report, we found that the elemental sulfur reduction is quite common in different species of genus Sulfurimonas. To gain insights into the sulfur reduction mechanism, growth tests, morphology observation, as well as genomic and transcriptomic analyses were performed on a deep-sea hydrothermal vent bacterium Sulfurimonas sp. NW10. Scanning electron micrographs and dialysis tubing tests confirmed that elemental sulfur reduction occurred without direct contact of cells with sulfur particles while direct access strongly promoted bacterial growth. Furthermore, we demonstrated that most species of Sulfurimonas probably employ both periplasmic and cytoplasmic polysulfide reductases, encoded by genes psrA1 B1 CDE and psrA2 B2 , respectively, to accomplish cyclooctasulfur reduction. This is the first report showing two different sulfur reduction pathways coupled to different energy conservations could coexist in one sulfur-reducing microorganism, and demonstrates that most bacteria of Sulfurimonas could employ both periplasmic and cytoplasmic polysulfide reductases to perform cyclooctasulfur reduction. The capability of sulfur reduction coupling with hydrogen oxidation may partially explain the prevalenceof Sulfurimonas in deep-sea hydrothermal vent environments.

A Suspended Silicon Single-Hole Transistor as an Extremely Scaled Gigahertz Nanoelectromechanical Beam Resonator.

Suspended single-hole transistors (SHTs) can also serve as nanoelectromechanical resonators, providing an ideal platform for investigating interactions between mechanical vibrations and charge carriers. Demonstrating such a device in silicon (Si) is of particular interest, due to the strong piezoresistive effect of Si and potential applications in Si-based quantum computation. Here, a suspended Si SHT also acting as a nanoelectromechanical beam resonator is demonstrated. The resonant frequency and zero-point motion of the device are ≈3 GHz and 0.2 pm, respectively, reaching the best level among similar devices demonstrated with Si-containing materials. The mechanical vibration is transduced to electrical readout by the SHT. The signal transduction mechanism is dominated by the piezoresistive effect. A giant apparent effective piezoresistive gauge factor with strong correlation to single-hole tunneling is extracted in this device. The results show the great potential of the device in interfacing charge carriers with mechanical vibrations, as well as investigating potential quantum behavior of the vibration phonon mode.

Synergy of Ionic and Dipolar Effects by Molecular Design for pH Sensing beyond the Nernstian Limit.

Knowledge of interfacial interactions between analytes and functionalized sensor surfaces, from where the signal originates, is key to the development and application of electronic sensors. The present work explores the tunability of pH sensitivity by the synergy of surface charge and molecular dipole moment induced by interfacial proton interactions. This synergy is demonstrated on a silicon-nanoribbon field-effect transistor (SiNR-FET) by functionalizing the sensor surface with properly designed chromophore molecules. The chromophore molecules can interact with protons and lead to appreciable changes in interface dipole moment as well as in surface charge state. In addition, the dipole moment can be tuned not only by the substituent on the chromophore but also by the anion in the electrolyte interacting with the protonated chromophore. By designing surface molecules to enhance the surface dipole moment upon protonation, an above-Nernstian pH sensitivity is achieved on the SiNR-FET sensor. This finding may bring an innovative strategy for tailoring the sensitivity of the SiNR-FET-based pH sensor toward a wide range of applications.

Thiomicrorhabdus indica sp. nov., an obligately chemolithoautotrophic, sulfur-oxidizing bacterium isolated from a deep-sea hydrothermal vent environment.

A new mesophilic bacterium, designated strain 13-15AT, was isolated from the deep-sea water from the Carlsberg Ridge, northwestern Indian Ocean. Cells were short rods and motile with a single polar flagellum. Growth was observed in the presence of 85-1700 mM NaCl (optimum 680 mM), at 10-45 °C (optimum, 28 °C) and pH 5.0-9.0 (optimum, pH 7.0). The isolate was an obligate chemolithoautotroph capable of growth using thiosulfate, sulfide, elemental sulfur or tetrathionate as the sole energy source, carbon dioxide as the sole carbon source, and molecular oxygen as the sole electron acceptor. Molecular hydrogen did not support growth. The major fatty acids were C16 : 1 (45.0 %), C18 : 1 (22.5 %) and C16 : 0 (20.1 %). The G+C content of the genomic DNA was 41.6 mol%. The results of phylogenetic analysis based on 16S rRNA gene sequences showed that the novel isolate belonged to the genus Thiomicrorhabdus and was most closely related to Thiomicrorhabdus hydrogeniphila MAS2T (94.8 % sequence similarity). On the basis of the taxonomic data obtained in this study, strain 13-15AT represents a novel species of the genus Thiomicrorhabdus, for which the name Thiomicrorhabdus indica sp. nov. is proposed, with the type strain 13-15AT (=MCCC 1A13986T=KCTC 15750T).

Device Noise Reduction for Silicon Nanowire Field-Effect-Transistor Based Sensors by Using a Schottky Junction Gate.

The sensitivity of metal oxide semiconductor field-effect transistor (MOSFET) based nanoscale sensors is ultimately limited by noise induced by carrier trapping/detrapping processes at the gate oxide/semiconductor interfaces. We have designed a Schottky junction gated silicon nanowire field-effect transistor (SiNW-SJGFET) sensor, where the Schottky junction replaces the noisy oxide/semiconductor interface. Our sensor exhibits significantly reduced device noise, 2.1 × 10-9 V2 µm2/Hz at 1 Hz, compared to reference devices with the oxide/semiconductor interface operated at both inversion and depletion modes. Further improvement can be anticipated by wrapping the nanowire by such a Schottky junction, thereby eliminating all oxide/semiconductor interfaces. Hence, a combination of the low-noise SiNW-SJGFET device with a sensing surface of the Nernstian response limit holds promises for future high signal-to-noise ratio sensor applications.

Atomic layer confined vacancies for atomic-level insights into carbon dioxide electroreduction.

The role of oxygen vacancies in carbon dioxide electroreduction remains somewhat unclear. Here we construct a model of oxygen vacancies confined in atomic layer, taking the synthetic oxygen-deficient cobalt oxide single-unit-cell layers as an example. Density functional theory calculations demonstrate the main defect is the oxygen(II) vacancy, while X-ray absorption fine structure spectroscopy reveals their distinct oxygen vacancy concentrations. Proton transfer is theoretically/experimentally demonstrated to be a rate-limiting step, while energy calculations unveil that the presence of oxygen(II) vacancies lower the rate-limiting activation barrier from 0.51 to 0.40 eV via stabilizing the formate anion radical intermediate, confirmed by the lowered onset potential from 0.81 to 0.78 V and decreased Tafel slope from 48 to 37 mV dec-1. Hence, vacancy-rich cobalt oxide single-unit-cell layers exhibit current densities of 2.7 mA cm-2 with ca. 85% formate selectivity during 40-h tests. This work establishes a clear atomic-level correlation between oxygen vacancies and carbon dioxide electroreduction.

Ultrathin Co3O4 Layers Realizing Optimized CO2 Electroreduction to Formate.

Electroreduction of CO2 into hydrocarbons could contribute to alleviating energy crisis and global warming. However, conventional electrocatalysts usually suffer from low energetic efficiency and poor durability. Herein, atomic layers for transition-metal oxides are proposed to address these problems through offering an ultralarge fraction of active sites, high electronic conductivity, and superior structural stability. As a prototype, 1.72 and 3.51 nm thick Co3O4 layers were synthesized through a fast-heating strategy. The atomic thickness endowed Co3O4 with abundant active sites, ensuring a large CO2 adsorption amount. The increased and more dispersed charge density near Fermi level allowed for enhanced electronic conductivity. The 1.72 nm thick Co3O4 layers showed over 1.5 and 20 times higher electrocatalytic activity than 3.51 nm thick Co3O4 layers and bulk counterpart, respectively. Also, 1.72 nm thick Co3O4 layers showed formate Faradaic efficiency of over 60% in 20 h.