Entropy-induced high-density grain boundaries in Co-free high-entropy spinel oxides for highly reversible lithium storage.

Transition metal oxides (TMOs) with high discharge capacity are considered as one of the most promising anodes for lithium-ion batteries. However, the practical utilization of TMOs is largely limited by cycling stability issues arising from volume expansion, structural collapse. In this study, we synthesized a high-entropy spinel oxide material (FeCrNiMnZn)3O4 using a solution combustion method. With the implementation of five cations through high-entropy engineering, the agglomeration and expansion of the electrode materials during charging and discharging are suppressed, and the cycling stability is enhanced. The results demonstrate that entropy-induced high-density grain boundaries and the reversibility of spinel structure contribute to improved capacity and cycling stability. Herein, (FeCrNiMnZn)3O4 provides a high capacity (1374 mAh g-1) at 0.1 A g-1 and superior cycling stability (almost 100 %) during 200 cycles with a current density of 0.5 A g-1. The study provides valuable understanding for designing the high entropy oxides anode electrodes.

Wireless antenna sensor with CuO@Cu-vertical graphene and cysteine-PDMS composite for ethanol gas detection.

BACKGROUND: Ethanol gas sensors are widely used in driving safety, security, and clinical respiratory monitoring applications. However, most ethanol sensors are large and exhibit poor stability owing to their integrated controller and high-temperature operation. Moreover, the development of wireless controller-free room-temperature ethanol sensors with long-term reliability is challenging. RESULTS: In this study, a wireless room-temperature ethanol gas antenna sensor was developed by combining a Cu radiation electrode with vertical graphene (VG) embedded with CuO@Cu nanoparticles and a polydimethylsiloxane (PDMS) dielectric substrate filled with cysteine (Cys). In the patch-antenna sensor, changes in the ethanol gas concentration resulted in frequency shift differences in the generation and transmission processes of the synchronized sensing signal. The VG-Cu/Cys-PDMS ethanol gas sensor had a detection range of 50-2100 ppm and a low limit of detection (LOD) of 0.112 ppm, with a response/recovery time of only 20/21 s for 1200 ppm ethanol, thus demonstrating superior long-term stability and satisfactory humidity tolerance. Therefore, the synergistic sensitization mechanism between the VG sensing/radiation layer and Cys-PDMS substrate was investigated. SIGNIFICANCE: This approach effectively addresses the issues of low-temperature operation, miniaturization, and long-term reliability. The proposed patch-antenna gas sensor is suitable for large-scale production owing to its use of industrial chemical vapor deposition technology and could be used to develop Internet-of-Things gas sensor nodes owing to its wireless propagation of electromagnetic waves with sensing information.

Wireless Gold/Boron-Nitrogen-Codoped Graphene-Based Antenna Immunosensor for the Rapid Detection of Neuron-Specific Enolase.

Tumor-marker immunosensors for rapid on-site detection have not yet been developed because of immunoreaction bottlenecks, such as shortening the reaction time and facilitating incubation. In this study, a gold-boron-nitrogen-codoped graphene (Au-BNG)-based immunosensor antenna was constructed for the rapid detection of neuron-specific enolase (NSE). A Au-BNG radiation electrode with dual functions of antibody protein fixation and signal transmission was developed for the first time. A radiation sample cell was constructed by embedding a radiation electrode into the groove of a poly(dimethylsiloxane) dielectric substrate. The constructed sense antenna achieves accurate detection of NSE with a range from 50 fg mL-1 to 40,000 pg mL-1 and a limit of detection of 10.99 fg mL-1, demonstrating excellent selectivity, stability, and reliability. The tumor-marker detection meter can provide NSE detection results as rapidly as within 2 min by using the new strategy of the microwave self-incubation of tumor markers. This antenna immunosensor is suitable for rapid detection in outpatient clinics and can be developed into household tumor-marker detectors, which would be significant in the early detection, long-term monitoring, and efficacy evaluation of tumors.

Electrochemical needle sensor based on a B, N co-doped graphene microelectrode array for the on-site detection of salicylic acid in fruits and vegetables.

In this study, a microelectrode array sensor based on boron and nitrogen co-doped vertical graphene (BNVG) was assembled to quantify salicylic acid (SA) in living plants. The influence of B and N contents on the electrochemical reaction kinetics and SA response signal was investigated. A microneedle sensor with three optimized BNVG microelectrodes (3.57 at.% B and 3.27 at.% N) was used to quantitatively analyze SA in the 0.5-100 µM concentration range and pH 4.0-9.0, with limits of detection of 0.14-0.18 µM. Additionally, a quantitative electrochemical model database based on the BNVG microelectrode sensor was constructed to monitor the growth of cucumbers and cauliflowers, which confirmed that the SA level and plant growth rate were positively correlated. Moreover, the SA levels in various vegetables and fruits purchased from the market were measured to demonstrate the practical application prospects for on-site inspection and evaluation.

The elevation of salinity above 1% deteriorated nitrification performance and reshaped nitrifier community of an MBR: An often overlooked factor in the treatment of high-strength ammonium wastewater.

The effects of synchronous variations of influent salinity with the elevation of NH4+-N concentration on nitrification performance and microbial community structure of bioreactor are often ignored. In this study, we investigated the dynamic response of nitrifying activated sludge to synchronously increased salinity and ammonia loading rate (ALR) in a nitrification membrane bioreactor (MBR). We found that the increase in influent salinity above 1% (from 0.91 to 1.32%) led to the deterioration of the nitrification performance of the MBR. The combined inhibition effect of salinity (1.32%), free ammonia (FA, an average of 1.37 mg/L), and free nitrous acid (FNA, an average of 0.155 mg/L) on nitrite-oxidizing bacteria (NOB) resulted in long-term (35 days) nitrite accumulation. The further increase of salinity and ALR exhibited little influence on the nitrification performance of MBR after the activated sludge had adapted to high salinity (>1%), effective nitrification performance was achieved at high ALR up to 1.71 kg NH4+-N/m3·d and high salinity (2.13%). The microbial analysis showed that the elevated salinity and accumulation of FNA reshaped the microbial community structure of ammonia-oxidizing bacteria (AOB) and NOB. The dominant species of AOB and NOB shifted from the salinity-resistant species Nitrosomonas aestuarii to the species Nitrosomonas mobilis with dual resistant to salinity and FNA, and from non-salinity-resistant species Candidatus Nitrospira defluvii to salinity-resistant species Nitrobacter winogradskyi and Nitrospira marina, respectively. Therefore, the salinity of 1% may be a critical level for the nitrification performance and the shift in the nitrifier community of activated sludge without salinity acclimation.

Isolation of full-length IgG antibodies from combinatorial libraries expressed in the cytoplasm of Escherichia coli.

Here we describe a facile and robust genetic selection for isolating full-length IgG antibodies from combinatorial libraries expressed in the cytoplasm of redox-engineered Escherichia coli cells. The method is based on the transport of a bifunctional substrate comprised of an antigen fused to chloramphenicol acetyltransferase, which allows positive selection of bacterial cells co-expressing cytoplasmic IgGs called cyclonals that specifically capture the chimeric antigen and sequester the antibiotic resistance marker in the cytoplasm. The utility of this approach is first demonstrated by isolating affinity-matured cyclonal variants that specifically bind their cognate antigen, the leucine zipper domain of a yeast transcriptional activator, with subnanomolar affinities, which represent a ~20-fold improvement over the parental IgG. We then use the genetic assay to discover antigen-specific cyclonals from a naïve human antibody repertoire, leading to the identification of lead IgG candidates with affinity and specificity for an influenza hemagglutinin-derived peptide antigen.

Preparation of self-supporting vertically/horizontally grown graphene microelectrodes for neurotransmitter determination.

The development of microelectrodes for the rapid in situ detection of neurotransmitters and their metabolic levels in human biofluids has considerable significance in biomedical research. In this study, self-supported graphene microelectrodes with B-doped, N-doped, and B- and N-co-doped vertical graphene (BVG, NVG, and BNVG, respectively) nanosheets grown on horizontal graphene (HG) were fabricated for the first time. The high electrochemical catalytic activity of BVG/HG on monoamine compounds was explored by investigating the influence of B and N atoms and the VG layer thickness on the response current of neurotransmitters. Quantitative analysis using the BVG/HG electrode in a blood-like environment with pH 7.4 indicated that the linear concentration ranges were 1-400 and 1-350 µM for dopamine (DA) and serotonin (5-HT), with limits of detection (LODs) of 0.271 and 0.361 µM, respectively. For tryptophan (Trp), the sensor measured a wide linear concentration range of 3-1500 µM over a wide pH range of 5.0-9.0, with the LOD fluctuating between 0.58 and 1.04 µM. Furthermore, the BVG/HG microelectrodes could be developed as needle- and pen-type sensors for the detection of DA, 5-HT, and Trp in human blood and gastrointestinal secretion samples.

Removal of tetracycline in nitrification membrane bioreactors with different ammonia loading rates: Performance, metabolic pathway, and key contributors.

Membrane bioreactors (MBRs) have been widely applied for the treatment of wastewater that contains high concentrations of both ammonium and antibiotics. Nonetheless, information about tetracycline (TC) removal in nitrification MBRs with high ammonium loading rates (ALRs) is still very limited. Herein, the fate of TC at four different concentrations of 1, 5, 20, and 50 mg/L in three parallel lab-scale nitrification MBRs with different ALRs (named AN50, AN500, and AN1000) were investigated in this study. Excellent nitrification performance and high TC removal efficiency (90.46%) were achieved in AN1000 at influent TC concentration of 50 mg/L. Higher ALRs promoted the removal of TC at lower influent TC concentration (≤5 mg/L), while no significant difference was observed in TC removal efficiencies among different ALRs MBRs at higher influent TC concentration (≥20 mg/L), implying that the heterotrophic degradation could be strengthened after long-term exposure to high concentration of TC. Batch tests demonstrated that adsorption and biodegradation were the primary TC removal routes by nitrification sludge, of which both autotrophic ammonia oxidizers and heterotrophic microorganisms played an important role in the biodegradation of TC. FT-IR spectroscopy confirmed that amide groups on the sludge biomass contributed to the adsorption of TC. Mass balance analyses indicated that biodegradation (63.4-88.6% for AN50, 74.5-88.4% for AN500 and 74.4-91.4% for AN1000) was the major mechanism responsible for the removal of TC in nitrification MBRs, and its contribution increased with influent TC concentration, while only 1.1%-15.0% of TC removal was due to biosorption. TC was progressively degraded to small molecules and the presence of TC had no notable effect on membrane permeability. These jointly confirmed TC could be effectively removed via initial adsorption and subsequent biodegradation, while biodegradation was the primary mechanism in this study.

Two-channel electrochemical immunosensor based on one-step-synthesized AuPt-boron-doped graphene electrode for CA153 detection.

Herein, a novel dual-channel electrochemical immunosensor was fabricated via vertical growth of AuPt-decorated boron-doped graphene (AuPt-BG) nanosheets as a signal amplification platform to detect cancer antigen 153 (CA153). Highly open, porous AuPt-BG films were synthesized using one-step electron-assisted hot-filament chemical vapor deposition. The Au-Pt alloy nanoparticles were dispersed on BG nanosheets to improve their biocompatibility, and antibodies (Ab) were directly bonded to the AuPt-BG electrode. The architectures enlarged the loading of CA153Ab and efficiently catalyzed the Fe(CN)63-/4- reaction, ultimately amplifying the signals. This novel strategy allows the simultaneous detection of CA153 in the oxidation and reduction channels, improving the reliability of the detection results. The AuPt-BG-based immunosensor exhibited a lower detection limit (0.0012 mU mL-1, S/N = 3) and wider linear range (0.1-4 × 104 mU mL-1) along with improved reproducibility, selectivity, and stability for the assay of CA153. Owing to the high process controllability of AuPt-BG films, a large-area electrode for in-vitro analyses and a flexible microelectrode for in-vivo analyses were prepared, which confirmed that the AuPt-BG-based sensor is an ideal CA153 detection platform for clinical diagnosis and practical applications.

Attention-based 3D convolutional recurrent neural network model for multimodal emotion recognition.

Introduction: Multimodal emotion recognition has become a hot topic in human-computer interaction and intelligent healthcare fields. However, combining information from different human different modalities for emotion computation is still challenging. Methods: In this paper, we propose a three-dimensional convolutional recurrent neural network model (referred to as 3FACRNN network) based on multimodal fusion and attention mechanism. The 3FACRNN network model consists of a visual network and an EEG network. The visual network is composed of a cascaded convolutional neural network-time convolutional network (CNN-TCN). In the EEG network, the 3D feature building module was added to integrate band information, spatial information and temporal information of the EEG signal, and the band attention and self-attention modules were added to the convolutional recurrent neural network (CRNN). The former explores the effect of different frequency bands on network recognition performance, while the latter is to obtain the intrinsic similarity of different EEG samples. Results: To investigate the effect of different frequency bands on the experiment, we obtained the average attention mask for all subjects in different frequency bands. The distribution of the attention masks across the different frequency bands suggests that signals more relevant to human emotions may be active in the high frequency bands γ (31-50 Hz). Finally, we try to use the multi-task loss function Lc to force the approximation of the intermediate feature vectors of the visual and EEG modalities, with the aim of using the knowledge of the visual modalities to improve the performance of the EEG network model. The mean recognition accuracy and standard deviation of the proposed method on the two multimodal sentiment datasets DEAP and MAHNOB-HCI (arousal, valence) were 96.75 ± 1.75, 96.86 ± 1.33; 97.55 ± 1.51, 98.37 ± 1.07, better than those of the state-of-the-art multimodal recognition approaches. Discussion: The experimental results show that starting from the multimodal information, the facial video frames and electroencephalogram (EEG) signals of the subjects are used as inputs to the emotion recognition network, which can enhance the stability of the emotion network and improve the recognition accuracy of the emotion network. In addition, in future work, we will try to utilize sparse matrix methods and deep convolutional networks to improve the performance of multimodal emotion networks.

A universal glycoenzyme biosynthesis pipeline that enables efficient cell-free remodeling of glycans.

The ability to reconstitute natural glycosylation pathways or prototype entirely new ones from scratch is hampered by the limited availability of functional glycoenzymes, many of which are membrane proteins that fail to express in heterologous hosts. Here, we describe a strategy for topologically converting membrane-bound glycosyltransferases (GTs) into water soluble biocatalysts, which are expressed at high levels in the cytoplasm of living cells with retention of biological activity. We demonstrate the universality of the approach through facile production of 98 difficult-to-express GTs, predominantly of human origin, across several commonly used expression platforms. Using a subset of these water-soluble enzymes, we perform structural remodeling of both free and protein-linked glycans including those found on the monoclonal antibody therapeutic trastuzumab. Overall, our strategy for rationally redesigning GTs provides an effective and versatile biosynthetic route to large quantities of diverse, enzymatically active GTs, which should find use in structure-function studies as well as in biochemical and biomedical applications involving complex glycomolecules.

Customizing the Appearance of Sparks with Binary Metal Alloys.

Long-flying sparks are an essential part of several pyrotechnic effects. Unfortunately, and in contrast to colored flames, the color space of sparks is basically limited to the black body curve. With low-boiling-point metals, vapor-phase combustion and bright colorful flashes are achievable. Since 1999, alloys of rare-earth elements have been proposed for colorful spark generation. To the best of our knowledge, here, we present the first investigation of such alloys to change the color of sparks beyond the black body limit. Alloys consisting of >65 at. % of a brightly emitting and low-boiling-point metal and a carrier metal allow achieving long-flying deeply colored sparks. Besides the color, branching of sparks is crucial for the visual appearance. Rare-earth metals were found to promote branching of different alloys. Finally, fountains ejecting golden/green sparks based on a stable eutectic Yb-Cu alloy and continuously branching sparks based on Nd2Fe14B are presented.

A label-free electrochemical immunosensor based on a gold-vertical graphene/TiO2 nanotube electrode for CA125 detection in oxidation/reduction dual channels.

A label-free immunosensor was constructed in oxidation and reduction dual channel mode for the trace detection of cancer antigen 125 (CA125) in serum. The gold-vertical graphene/titanium dioxide (Au-VG/TiO2) electrode was used as the signal-amplification platform, and cytosine and dopamine were used as probes in the oxidation and reduction channels, respectively. VG nanosheets were synthesized on a TiO2 nanotube array via chemical vapor deposition (CVD), and Au nanoparticles were deeply embedded on the surface and in the root of the VG nanosheets via electrodeposition. The CA125 antibody was then directly immobilized onto the electrode surface, benefitting from its natural affinity for Au nanoparticles. In the oxidation and reduction channels the CA125 antibody-Au-VG/TiO2 immune electrode had the same response concentration range (0.01-1000 mU∙mL-1) for the determination of the CA125 antigen. However, the oxidation channel had a higher sensitivity (14.82 µA•(log(mU•mL-1))-1 at a working potential of ~ 1.25 V vs. SCE), lower detection limit (0.0001 mU∙mL-1), higher stability, and lower performance deviation than the reduction channel. This immunosensor was successfully used for CA125 detection in human serum. The recoveries of spiked serum samples ranged from 99.8 ± 0.5 to 100 ± 0.4%. The study on the difference in the sensing performance between oxidation and reduction channels provides a preliminary experimental reference for exploring dual-channel synchronous detection immunosensors and verifying the accuracy of the assay based on dual-channel data, which will promote the development of reliable electrochemical immunosensor technology.

Molecularly imprinted Ni-polyacrylamide-based electrochemical sensor for the simultaneous detection of dopamine and adenine.

Molecularly imprinted polymer (MIP) membranes prepared in situ present several advantages: they maintain the original morphology, adhere strongly to the collector, and exhibit a controllable structure. In this study, a Ni-polyacrylamide (PAM)-MIP matrix was fabricated in situ on glassy carbon via the one-step electro-polymerization of AM monomers in the presence of Ni and template molecules. Ni2+ ions were introduced as oxidants to promote AM polymerization and bulking agents to fabricate a three-dimensional porous PAM-MIP matrix. The Ni-PAM-based MIP sensor exhibited a quantitative dual response toward dopamine (DA) and adenine (Ade) in the pH range of 5.0-9.0. The linear concentration range changed depending on the pH environment, and the concentrations of DA and Ade ranged from 0.6 to 200 µM and from 0.4 to 300 µM, respectively. The ranges of detection limits (S/N = 3) were 0.12-0.37 µM for DA and 0.15-0.36 µM for Ade. In addition, the dual-MIP sensor exhibited high reliability in the detection of DA and Ade in human serum owing to its excellent anti-interference ability and long-term stability. The technique developed in this study is expected to facilitate the construction of multi-target response electrochemical biosensors and the reliable determination of small molecules with high selectivity and stability.

Surface acoustic wave sensor based on Au/TiO2/PEDOT with dual response to carbon dioxide and humidity.

A surface acoustic wave (SAW) gas sensor with an Au/TiO2/poly(3,4-ethylenedioxythiophene) (PEDOT, which is a conductive polymer with photoelectric conversion function) sensing film was constructed for the quantitative detection of water vapor and CO2. The Au/TiO2/PEDOT sensing film was assembled on the delayed region of the 204 MHz SAW delay line, which was used as the base device for the gas sensor. The center frequency of the sensor decreases with an increase in relative humidity (RH), and the center frequency increases with increasing CO2 concentration, so that not only can the two gases be identified, but quantitative analysis can also be performed. The SAW sensor has a response range of 5%-90% for RH and a response range of 500-2000 ppm for CO2 gas. The shifts in center frequency varied linearly with the concentrations, giving rise to the sensitivities of -0.0068 and -0.1880 kHz %-1 for RH and ∼0.003 kHz ppm-1 CO2. The response/recovery time is 9 s/9.2 s for 700 ppm CO2 and 15 s/14 s for 70% RH. The experimental results show that the SAW sensor offers excellent selectivity, wide response range, rapid response, and good stability and repeatability. The mechanism of humidity and CO2 sensing is attributed to the hydrophilic porous structure of the Au/TiO2/PEDOT sensing film, and also to the reversible variation of its viscoelasticity under illumination conditions. The sensor, combined with the communication function of its own SAW device, has several prospective applications in the monitoring of atmospheric conditions.

Engineering a Supersecreting Strain of Escherichia coli by Directed Coevolution of the Multiprotein Tat Translocation Machinery.

Escherichia coli remains one of the preferred hosts for biotechnological protein production due to its robust growth in culture and ease of genetic manipulation. It is often desirable to export recombinant proteins into the periplasmic space for reasons related to proper disulfide bond formation, prevention of aggregation and proteolytic degradation, and ease of purification. One such system for expressing heterologous secreted proteins is the twin-arginine translocation (Tat) pathway, which has the unique advantage of delivering correctly folded proteins into the periplasm. However, transit times for proteins through the Tat translocase, comprised of the TatABC proteins, are much longer than for passage through the SecYEG pore, the translocase associated with the more widely utilized Sec pathway. To date, a high protein flux through the Tat pathway has yet to be demonstrated. To address this shortcoming, we employed a directed coevolution strategy to isolate mutant Tat translocases for their ability to deliver higher quantities of heterologous proteins into the periplasm. Three supersecreting translocases were selected that each exported a panel of recombinant proteins at levels that were significantly greater than those observed for wild-type TatABC or SecYEG translocases. Interestingly, all three of the evolved Tat translocases exhibited quality control suppression, suggesting that increased translocation flux was gained by relaxation of substrate proofreading. Overall, our discovery of more efficient translocase variants paves the way for the use of the Tat system as a powerful complement to the Sec pathway for secreted production of both commodity and high value-added proteins.

Shotgun scanning glycomutagenesis: A simple and efficient strategy for constructing and characterizing neoglycoproteins.

As a common protein modification, asparagine-linked (N-linked) glycosylation has the capacity to greatly influence the biological and biophysical properties of proteins. However, the routine use of glycosylation as a strategy for engineering proteins with advantageous properties is limited by our inability to construct and screen large collections of glycoproteins for cataloguing the consequences of glycan installation. To address this challenge, we describe a combinatorial strategy termed shotgun scanning glycomutagenesis in which DNA libraries encoding all possible glycosylation site variants of a given protein are constructed and subsequently expressed in glycosylation-competent bacteria, thereby enabling rapid determination of glycosylatable sites in the protein. The resulting neoglycoproteins can be readily subjected to available high-throughput assays, making it possible to systematically investigate the structural and functional consequences of glycan conjugation along a protein backbone. The utility of this approach was demonstrated with three different acceptor proteins, namely bacterial immunity protein Im7, bovine pancreatic ribonuclease A, and human anti-HER2 single-chain Fv antibody, all of which were found to tolerate N-glycan attachment at a large number of positions and with relatively high efficiency. The stability and activity of many glycovariants was measurably altered by N-linked glycans in a manner that critically depended on the precise location of the modification. Structural models suggested that affinity was improved by creating novel interfacial contacts with a glycan at the periphery of a protein-protein interface. Importantly, we anticipate that our glycomutagenesis workflow should provide access to unexplored regions of glycoprotein structural space and to custom-made neoglycoproteins with desirable properties.

Formation of Titanium Nitride, Titanium Carbide, and Silicon Carbide Surfaces by High Power Femtosecond Laser Treatment.

Invited for this month's cover is the group of Prof. Eike G. Hübner at Fraunhofer Heinrich Hertz Institute HHI, Goslar and Clausthal University of Technology, Clausthal-Zellerfeld, Germany. The cover picture shows a titanium plate, on which the crystal structure (golden circle=Ti, blue circle=O/N/C) of isomorphous TiO, TiN or TiC, respectively, has been engraved by a high-power high pulse repetition rate femtosecond laser process. The process allows for a fast and spatially resolved surface transformation of titanium to golden TiN, blue TiO/TiO2 or black TiC in an atmosphere of nitrogen, air or ethene/argon. The background represents a typical surface microstructure of these interstitial compounds obtained during this transformation. Read the full text of the article at 10.1002/cplu.202100118.

Engineering Single Pan-Specific Ubiquibodies for Targeted Degradation of All Forms of Endogenous ERK Protein Kinase.

Ubiquibodies (uAbs) are a customizable proteome editing technology that utilizes E3 ubiquitin ligases genetically fused to synthetic binding proteins to steer otherwise stable proteins of interest (POIs) to the 26S proteasome for degradation. The ability of engineered uAbs to accelerate the turnover of exogenous or endogenous POIs in a post-translational manner offers a simple yet robust tool for dissecting diverse functional properties of cellular proteins as well as for expanding the druggable proteome to include tumorigenic protein families that have yet-to-be successfully drugged by conventional inhibitors. Here, we describe the engineering of uAbs composed of human carboxyl-terminus of Hsc70-interacting protein (CHIP), a highly modular human E3 ubiquitin ligase, tethered to differently designed ankyrin repeat proteins (DARPins) that bind to nonphosphorylated (inactive) and/or doubly phosphorylated (active) forms of extracellular signal-regulated kinase 1 and 2 (ERK1/2). Two of the resulting uAbs were found to be global ERK degraders, pan-specifically capturing all endogenous ERK1/2 protein forms and redirecting them to the proteasome for degradation in different cell lines, including MCF7 breast cancer cells. Taken together, these results demonstrate how the substrate specificity of an E3 ubiquitin ligase can be reprogrammed to generate designer uAbs against difficult-to-drug targets, enabling a modular platform for remodeling the mammalian proteome.

Au@SnO2-vertical graphene-based microneedle sensor for in-situ determination of abscisic acid in plants.

For developing electrochemical plant sensors, in-situ detection of hormone levels in living plants is worth attempting. A microneedle array sensor based on Au@SnO2-vertical graphene (VG)/Ta microelectrodes was constructed for analyzing abscisic acid (ABA) in plants. Graphene was vertically grown on Ta wires with a diameter of 0.6 mm by direct current arc plasma jet chemical vapor deposition with SnO2 as the Au catalyst carrier. These VG nanosheets were embedded with core-shell Au@SnO2 nanoparticles, and the formation mechanism of the sensing layer was investigated. Three Au@SnO2-VG microelectrodes, one Ti wire, and one Pt wire were packed into a microneedle array sensor with a three-electrode system. ABA was then quantitatively detected by direct electrocatalytic oxidation, which involves the synergistic catalytic effects of the abundant catalytic active sites of the Au@SnO2 nanoparticles and the excellent conductivity of the VG nanosheets. The microneedle array sensor responds to ABA in the pH range 4-7, the response concentration range was 0.012 (or 0.024)-495.2 µM, and the detection limit varied between 0.002 and 0.005 µM. The small size, wide pH range, low detection limit, and wide linear concentration range allow the microneedle array sensor to be inserted into plants for in-situ detection of ABA.