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Microfluidic paper-based analytical devices (μPADs) are emerging as powerful analytical platforms in clinical diagnostics, food safety, and environmental protection because of their low cost and favorable substrate properties for biosensing. However, the existing top-down fabrication methods of paper-based chips suffer from low resolution (200 μm). Additionally, papers have limitations in their physical properties (e.g., thickness, transmittance, and mechanical flexibility). Here, we demonstrate a bottom-up approach for the rapid fabrication of heterogeneously controlled paper-based chip arrays. We simply print a wax-patterned microchip with wettability contrasts, enabling automatic and selective assembly of cellulose microfibers to construct predefined paper-based microchip arrays with controllable thickness. This paper-based microchip printing technology is feasible for various substrate materials ranging from inorganic glass to organic polymers, providing a versatile platform for the full range of applications including transparent devices and flexible health monitoring. Our bottom-up printing technology using cellulose microfibers as the starting material provides a lateral resolution down to 42 ± 3 μm and achieves the narrowest channel barrier down to 33 ± 2 μm. As a proof-of-concept demonstration, a flexible paper-based glucose monitor is built for human health care, requiring only 0.3 μL of sample for testing.

The cellular response to the complex extracellular microenvironment is highly dynamic in time and type of extracellular matrix. Accurately reconstructing this process and analyzing the changes in receptor conformation on the cell membrane surface and intracellular or intercellular signaling has been a major challenge in analytical chemistry and biophysical methodology. In this paper, a time-coded multi-concentration microfluidic chemical waveform generator was developed for the dynamic signaling probing with single-cell array of high temporal resolution, high throughput, and multi-concentration combination stimulation. Based on innovative microchannel structure, sophisticated external control methods and multiplexing technology, the system not only allowed for temporally sequential permutations of the four concentrations of stimuli (time code), but also generated pulsed and continuous waveforms at different frequencies in a highly controllable manner. Furthermore, the single-cell trap array was set up to efficiently capture cells in suspension, dramatically increasing throughput and reducing experiment preparation time. The maximum frequency of the platform was 1 Hz, and one cell could be stimulated at multiple frequencies. To show the ability of the system to investigate rapid biochemical events in high throughput, pulse stimulation and continuous stimulation of different frequencies and different time codes, combined with four concentrations of histamine (HA), were generated for probing G protein-coupled receptor (GPCR) signaling in HeLa cells. Then, statistical analysis was performed for the mean peak height and mean peak area of the cellular response. We believe that the time-coded multi-concentration microfluidic chemical waveform generator will provide a novel strategy for analytical chemistry, biophysics, cell signaling, and individualized medicine applications.

Since Major Depressive Disorder (MDD) represents a neurological pathology caused by inter-synaptic messaging errors, membrane receptors, the source of signal cascades, constitute appealing drugs targets. G protein-coupled receptors (GPCRs) and ion channel receptors chelated antidepressants (ADs) high-resolution architectures were reported to realize receptors physical mechanism and design prototype compounds with minimal side effects. Tyrosine kinase receptor 2 (TrkB), a receptor that directly modulates synaptic plasticity, has a finite three-dimensional chart due to its high molecular mass and intrinsically disordered regions (IDRs). Leveraging breakthroughs in deep learning, the meticulous architecture of TrkB was projected employing Alphfold 2 (AF2). Furthermore, the Alphafold Multimer algorithm (AF-M) models the coupling of intra- and extra-membrane topologies to chaperones: mBDNF, SHP2, Etc. Conjugating firmly dimeric transmembrane helix with novel compounds like 2R,6R-hydroxynorketamine (2R,6R-HNK) expands scopes of drug screening to encompass all coding sequences throughout genomes. The operational implementation of TrkB kinase-SHP2, PLCγ1, and SHC1 ensembles has paved the path for machine learning in which it can forecast structural transitions in the self-assembly and self-dissociation of molecules during trillions of cellular mechanisms. In silicon, the cornerstone of the alteration will be artificial intelligence (AI), empowering signal networks to operate at the atomic level and picosecond timescales.

Microchip has long been studied and facilitated recent investigations in multiple biomedical and material fields. The advances in functional materials triggered several leaps in the development of microchip technology. Microarray chip, benefiting from micropatterning and nucleic acid nanotechnology, was firstly introduced around 1980 and rapidly facilitated genomics, proteomics, and biodetections. In the following generation, the microfluidic chips, raised from microelectromechanical systems (MEMS) and soft lithography, are revolutionizing several areas like biology, material fabrication, energy, and environmental science. More recently, the advances in materials fabrication keep expanding the frontiers of microchip platforms, like nanoscale fabrications and flexible device manufacturing. One of the most promising platforms is the wettability-patterned materials inspired by ubiquitous natural wetting creatures such as lotus leaf, spider silk, and Stenocara beetles. The unique property of handling liquids with no sophisticated equipment potentially facilitated the current microchip platform by combining the merits of microarray and microfluidics, and in turn, benefits material communities and beyond. In this featured article, we briefly introduce the state of art technologies to fabricate wettability-patterned chips and highlight some proof-of-concept demonstration of its emerging applications in material and biomedical science. We also give an outlook on its further developments including machine-learning micropattern manufacturing technology and reveal its potentiality to revolute several scientific areas.

Wnt/β-catenin signaling is a conserved pathway crucially governing development, homeostasis and oncogenesis. Discovery of novel regulators holds great values in both basic and translational research. Through screening, we identified a deubiquitinase (DUB) USP10 as a novel and critical modulator of β-catenin. Mechanistically, USP10 binds to key scaffold Axin1 via conserved motifs and stabilizes Axin1 through K48-linked deubiquitination, and surprisingly, tethers Axin1 and β-catenin physically while promoting phase separation for β-catenin suppression regardless of its enzymatic activity. Functionally, USP10 prominently regulates embryonic development and intestinal homeostasis by antagonizing β-catenin via DUB activity. In colorectal cancer, USP10 substantially represses cancer growth mainly through physical binding compensation and phase separation promotion and correlates with Wnt/β-catenin magnitude clinically. Collectively, we discovered USP10 functioning in multiple biological processes against β-catenin and unearthed a novel enzyme-dependent and -independent “dual-regulating” mechanism by which USP10 utilizes parallelly and context-dependently. USP10 inhibitor was suggested in treating certain Wnt-related diseases.

Esophageal cancer (EC), gastric cancer (GC), and colorectal cancer (CRC) are three major digestive tract tumors with higher morbidity and mortality due to significant molecular heterogeneity. Altered IgG glycosylation has been observed in inflammatory activities and disease progression, and the IgG glycome profile could be used for disease stratification. However, IgG

The Coronavirus disease 2019 (COVID-19) outbreak has urged the establishment of a global-wide rapid diagnostic system. Current widely-used tests for COVID-19 include nucleic acid assays, immunoassays, and radiological imaging. Immunoassays play an irreplaceable role in rapidly diagnosing COVID-19 and monitoring the patients for the assessment of their severity, risks of the immune storm, and prediction of treatment outcomes. Despite of the enormous needs for immunoassays, the widespread use of traditional immunoassay platforms is still limited by high cost and low automation, which are currently not suitable for point-of-care tests (POCTs). Microfluidic chips with the features of low consumption, high throughput, and integration, provide the potential to enable immunoassays for POCTs, especially in remote areas. Meanwhile, luminescence detection can be merged with immunoassays on microfluidic platforms for their good performance in quantification, sensitivity, and specificity. This review introduces both homogenous and heterogenous luminescence immunoassays with various microfluidic platforms. We also summarize the strengths and weaknesses of the categorized methods, highlighting their recent typical progress. Additionally, different microfluidic platforms are described for comparison. The latest advances in combining luminescence immunoassays with microfluidic platforms for POCTs of COVID-19 are further explained with antigens, antibodies, and related cytokines. Finally, challenges and future perspectives were discussed.

Cells in their native microenvironment are subjected to varying combinations of biochemical cues and mechanical cues in a wide range. Although many signaling pathways have been found to be responsive for extracellular cues, little is known about how biochemical cues crosstalk with mechanical cues in a complex microenvironment. Here, we introduced heterogeneous droplets on a microchip, which were rapidly assembled by combining wettability-patterned microchip and programmed droplet manipulations, for a high-throughput cell screening of the varying combinations of biochemical cues and mechanical cues. This platform constructed a heterogeneous droplet/microgel array with orthogonal gradual chemicals and materials, which was further applied to analyze the cellular Wnt/β-catenin signaling in response to varying combinations of Wnt ligands and substrate stiffness. Thus, this device provides a powerful multiplexed bioassay platform for drug development, tissue engineering, and stem cell screening.

Oxycodone is one of the most prescribed narcotic medications for the treatment of moderate to severe pain in clinical practice. During long-term stability studies of oxycodone hydrochloride for injection performed as per ICH Q1A (R2) guidelines, an unknown degradation product, impurity-I, increased over time and reached a level of 0.21% after 24 months, based on the results of HPLC analysis. The observed impurity was preliminarily characterized as an oxycodone aldol dimer by using two-dimensional (2D) liquid chromatography (LC) coupled with quadrupole time-of-flight mass spectrometry (QTOF MS/MS) analysis. Impurity-I was synthesized and its molecular structure confirmed based on detailed analysis of 1D-NMR (1H, 13C, and DEPT) and 2D-NMR (1H–1H COSY, HSQC, and HMBC) spectroscopy data. The plausible mechanism for the formation of impurity-I was an aldol condensation reaction under weakly acidic conditions. In addition, the potential toxicity of impurity-I was assessed by in silico toxicity predictions using the TOPKAT software.

Glyconanoparticles (G-NPs), biofunctional nanomaterials that can fully combine the unique properties of nanoparticles (NPs) with the bioactivities of carbohydrates, have become an appealing nanoplatform in analytical chemistry and biomedical research. However, there is currently a lack of an efficient and universal method for facile immobilization of reducing carbohydrates on NPs while maintaining their structure integrity, greatly limiting the preparation and application of G-NPs. Herein, a new and universal strategy for preparing carbohydrate-functionalized gold nanoclusters (Au NCs) was developed by using S-(3-(methoxyamino)propyl) thioacetate (MPTA) as a new bifunctional linker. MPTA with an N-methoxyamine group (-NHOMe) and a thioacetyl group (-SAc) was synthesized by a two-step strategy and then grafted onto Au NCs by an efficient click reaction. Subsequently, reducing carbohydrates could be readily immobilized onto MPTA-functionalized Au NCs (MPTA-Au NCs) by a reducing end ring-closure reaction under mild conditions. The obtained G-NPs showed average size of 1.9 ± 0.42 nm and strong fluorescence at 610 nm. Carbohydrates grafted on G-NPs still retained their structure integrity and specific recognition ability toward their receptor proteins. Notably, the affinity between G-NPs and proteins was increased by 1300 times compared with free carbohydrates with an association constant of (1.47 ± 0.356) × 10

Cell signaling greatly affected by complicated and temporally dynamic extracellular microenvironments controls most of the physiological functions in vivo. To reconstruct or simulate such microenvironments in vitro represents a fundamental approach for revealing the underlying mechanisms of those sophisticated processes. Recent advances in microfluidics have added a new dimension to cell signaling analysis, for example, concentration gradient generators (amplitude aspect) or hydrodynamic gating strategy (frequency aspect), but it is still challengeable to capture single-cell dynamic signaling in response to a mimicked extracellular microenvironment with varied stimuli waveforms of different amplitude and frequency in a high-throughput manner. In this article, we proposed a novel microfluidic strategy coupling multichannel synchronous hydrodynamic gating with microfluidic concentration gradient generators (μMHG-CGG) to probe dynamic signaling of single cells with high throughput. The μMHG-CGG allows rapid delivery of dynamic chemical signals in both high frequency (as high as 670 mHz) and multiple amplitude domains at the same time and simultaneously high-throughput probing cell dynamics at single-cell resolution in real time. By applying the proposed system, the mechanisms for encoding/decoding systems (termed "frequency coding" or "amplitude coding") via GPCRs-mediated signaling pathways responding to histamine (HA) and adenosine triphosphate (ATP) in single HeLa cells were investigated. The optimal drug concentrations of single cells responses to HA and ATP individually or in combination were also successfully discussed, allowing us to obtain both single-cell heterogeneity and statistics from the cell population.

Objectives The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has rapidly spread globally. The laboratory diagnosis of SARS-CoV-2 infection has relied on nucleic acid testing; however, it has some limitations, such as low throughput and high rates of false negatives. Tests of higher sensitivity are needed to effectively identify infected patients. Methods This study has developed fully automated chemiluminescent immunoassays to determine IgM and IgG antibodies to SARS-CoV-2 in human serum. The assay performance has been evaluated at 10 hospitals. Clinical specificity was evaluated by measuring 972 hospitalized patients and 586 donors of a normal population. Clinical sensitivity was assessed on 513 confirmed cases of SARS-CoV-2 by RT-PCR. Results The assays demonstrated satisfied assay precision with coefficient of variation of less than 4.45%. Inactivation of specimen did not affect assay measurement. SARS-CoV-2 IgM showed clinical specificity of 97.33 and 99.49% for hospitalized patients and the normal population respectively, and SARS-CoV-2 IgG showed clinical specificity of 97.43 and 99.15% respectively. SARS-CoV-2 IgM showed clinical sensitivity of 82.54, 92.93, and 84.62% before 7 days, 7–14 days, and after 14 days respectively, since onset of symptoms, and SARS-CoV-2 IgG showed clinical sensitivity of 80.95, 97.98, and 99.15% respectively at the same time points above. Conclusions We have developed fully automated immunoassays for detecting SARS-CoV-2 IgM and IgG antibodies in human serum. The assays demonstrated high clinical specificity and sensitivity, and add great value to nucleic acid testing in fighting against the global pandemic of the SARS-CoV-2 infection.

Different solid forms possess various physicochemical properties, which can significantly affect the stability, bioavailability, and manufacturability of the final product. DP-VPA, a complex of 1-stearoyl-2-valproyl-sn-glycero-3-phosphatidylcholine (DP-VPA-C18) and 1-palmitoyl-2-valproyl-sn-glycero-3-phosphatidylcholine (DP-VPA-C16), is currently under development as an antiepileptic drug. DP-VPA-C16 and DP-VPA-C18 crystallize together in solid solution forms. The solid forms of DP-VPA solid solution were studied herein. Powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), dynamic vapor sorption (DVS) and optical microscopy were used to characterize the different crystalline forms, known as polymorphs. The physicochemical properties, including hygroscopicity, thermodynamic behavior, and relative stability, of each form were investigated. DVS analysis showed that DP-VPA solid solution reduced the hygroscopicity of DP-VPA-C16. The relative humidity stability study revealed that Forms A and B are relatively stable, while Forms A-1, B-1, C and D are highly unstable under natural humidity. Further analysis revealed that Form A transforms into Form B through milling. Given the physicochemical properties of the available physical forms, Form B may be the optimal form for the formulation and development of antiepileptic drugs.

Photodynamic therapy (PDT) is a promising strategy for tumor treatment. Still, its therapeutic efficacy is compromised by the unsatisfactory cytotoxicity to specific subcellular organelles and insidious tumor microenvironment properties like hypoxia and high glutathione levels. Here, we fabricated a novel nanoenzyme that derived from metal-organic framework (MOF) with intrinsic catalase-like activities to decompose H2O2 to O2 and simultaneous glutathione consumption for enhancing PDT efficacy. The obtained Mn3O4 nanoparticle shows a larger pore size and surface area compared to native MOF particles, which can be used to load high dose photosensitizer. When decorated with AS1411 aptamer and polyethylene glycol (PEG), the obtained Mn3O4-PEG@C&A particle exhibits excellent stability and cell nucleus targeting ability. Remarkably, Mn3O4-PEG@C&A particle inhibited the tumor growth in the mouse model with high efficacy without any biotoxicity. This is the first report that applied MOF-derived nanoparticle to nucleus-targeted PDT. It may provide a new approach for designing functional nanoenzyme to subcellular organelles-targeted tumor modulation.

The three-dimensional hierarchical morphology of surfaces greatly affects the wettability, absorption and microfabrication properties of their hybrid materials, however few scalable methods exist that controls simultaneously complex geometric shape and spatial scattered location and their physical properties tuned. Consequently, this report describes a synthetic strategy that enables the position of well-ordered biomorph nano-microstructures on hydrophobic surfaces to be precisely controlled. The hierarchical architecture can be accurately positioned on polydimethylsiloxane (PDMS) surfaces in an unprecedented level by leveraging a solid/liquid/gas triphase dynamic reaction diffusion system strategy. The effect of salt concentrations, pH, CO2 levels, temperature and substrate patterning on this self-assembly process has been investigated, enabling protocols to be devised that enables the hydrophobic properties of the hierarchically assembled multiscale microstructures to be tuned as required. This combined top-down/bottom-up approach can be used to produce composites with outstanding hydrophobicity properties, affording superhydrophobic materials that are capable of retaining water droplets on their surfaces, even when the material is inverted by 180°, with a wide range of potential applications in oil/water separation technology and for selective cell recognition in biological systems.

The emerging consensus on organic matter (OM) cycling in soil and sediment proposes that a continuum of biological and geochemical processes in the micro-environment controls the fate of OM. However, spatio-temporal observation of the biogeochemical nature and behaviour of OM at the soil–water interfaces (SWIs) is impeded by the heterogonous and opaque nature of their microenvironment. Herein, we used a novel SoilChip method (soil microarrays incubated with a predefined solution) to continuously mimic and trace the OM biogeochemistry at SWIs for 21 days. Combining X-ray photoelectron spectroscopy and ion sputtering on SoilChips, we provided the first direct evidence that a nanoscale organic film with a distinct composition and thickness gradually formed at the SWI within 21 days of cultivation. Although the OM coating on the SWI quickly reached equilibrium within 4 days, the formation of thicker mineral–organic association (MOA, 20–130 nm) and microbial biomass (>130 nm) continued, partially at the cost of the thin MOA (

Colorectal cancer is associated with changed IgG glycosylation, but the alteration in specific subclasses of IgG is unknown. Initially, we optimized five common IgG glycopeptide enrichment methods to acquire a comprehensive profile of IgG glycopeptides. However, an incomplete tryptic digestion of IgG occurred when using an ordinary protease to protein ratio, which significantly impacted the final statistical analysis. Herein, we introduced a two-step enzymatic digestion, enabling the complete digestion of IgG glycopeptides and further improving the detection intensity of the target glycopeptides. In order to rapidly process and automatically integrate the MS data, we developed a simple and effective code using MATLAB. Following statistical analysis, we observed that IgG1_H3N4F1 and IgG1_H3N4 were substantially increased in CRC, while IgG1_H5N5F1, IgG1_H5N4F1S1 and IgG2_H5N4F1 were markedly decreased. A further evaluation of the diagnostic performance showed that they all achieved a fair performance in discriminating the patients from the normal. In terms of the glycan features, it was demonstrated that the CRC progression was associated with increased agalactosylation, and the decreased digalactosylation and galactosylation per antenna on the diantenna glycans of IgG1 and IgG2. Concurrently, the decreased sialylation of IgG1 was strongly correlated with CRC. Moreover, an analysis of tumor-specific glycosylation showed that the alterations of IgG glycosylation were more significant in colon cancer, and no obvious difference was observed between colon and rectal cancer. This study comprehensively optimized the glycopeptide enrichment methods, evaluated the enzymatic digestion effect, and explored the association between CRC progression and subclass-specific glycosylation.

We for the first time report that the activated CRISPR-Cas12a system trans-cleaves DNA G-quadruplexes (G4). The cleavage activity on human telomere G4 and TBA G4 was investigated and verified by FRET, CD, gel electrophoresis and NMR. We believe that this finding will pave a new avenue for advancing the applications of CRISPR-Cas12a and G4 in biosensing and biochemistry.

Point-of-care testing (POCT) has shown great advantages for public health monitoring in resource-limited settings. However, developing of POCT tools with automated and accurate quantitative dispensing of multiple reagents and samples is challenging. Here, we demonstrate a novel multi-reagents dispensing centrifugal microfluidics (MDCM) that allows rapid and automated dispensing of multiple reagents and samples with high throughput and accuracy. The MDCM was designed with multiple aliquoting units with the hydrophobic valve at different radial positions. All reagents and samples were loaded simultaneously, dispensed in parallel by centrifugation at low speed, and then introduced into the reaction chamber sequentially by centrifugation at high speed. Two MDCM chips are demonstrated, including a uniform concentration generator and a gradient concentration generator. The concentration coefficient of variation (CV) among the independent reaction chambers was lower than 0.56%, and the theoretical quantitative concentration gradient was strongly correlated with the actual concentration gradient (R

Biomolecular phase separation is currently emerging in both the medical and life science fields. Meanwhile, the application of liquid-liquid phase separation has been extended to many fields including drug discovery, fibrous material fabrication, 3D printing, and polymer design. Although more than 8600 proteins and other synthetic macromolecules are capable of phase separation as recently reported, there is still a lack of a high-throughput approach to quantitatively characterize its phase behaviors. To meet this requirement, here, we proposed fast and high-resolution acquisition of biomolecular phase diagrams using microfluidic chips. Using this platform, we demonstrated the phase behavior of polyU/RRASLRRASLRRASL in a quantitative manner. Up to 1750 concentration conditions can be generated in 140 min. The detection limitation of our device to capture the saturation concentration for phase separation is about 5 times lower than that of the traditional turbidity method. Thus, our results provide a basis for the rapid acquisition of phase diagrams with high-throughput and pave the way for its wide application.

Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide. Patients with inflammatory bowel disease (IBD) have a high risk of developing CRC. Inflammatory cytokines are regulated by complex gene networks and regulatory RNAs, especially microRNAs. MicroRNA-21 (miR-21) is amongst the most frequently upregulated microRNAs in inflammatory responses and cancer development. miR-21 has become a target for genetic and pharmacological regulation in various diseases. However, the association between inflammation and tumorigenesis in the gut is largely unknown. Hence, in this study, we generated a zebrafish model (ImiR-21) with inducible overexpression of miR-21 in the intestine. The results demonstrate that miR-21 can induce CRC or colitis-associated cancer (CAC) in ImiR-21 through the PI3K/AKT, PDCD4/TNF-α, and IL-6/STAT3 signaling network. miR-21 activated the PI3K/AKT and NF-κB signaling pathways, leading to initial inflammation, thereafter, miR-21 and TNF-α repressed PDCD4 and its tumor suppression activity. Eventually, active STAT3 stimulated a strong inflammatory response and activated the invasion/metastasis process of tumor cells. Hence, our findings indicate that miR-21 is critical for the development of CRC/CAC via the PI3K/AKT, STAT3, and PDCD4/TNF-α signaling networks.

Traditional diagnostic strategies for infectious disease detection require benchtop instruments that are inappropriate for point-of-care testing (POCT). Emerging microfluidics, a highly miniaturized, automatic, and integrated technology, are a potential substitute for traditional methods in performing rapid, low-cost, accurate, and on-site diagnoses. Molecular diagnostics are widely used in microfluidic devices as the most effective approaches for pathogen detection. This review summarizes the latest advances in microfluidics-based molecular diagnostics for infectious diseases from academic perspectives and industrial outlooks. First, we introduce the typical on-chip nucleic acid processes, including sample preprocessing, amplification, and signal read-out. Then, four categories of microfluidic platforms are compared with respect to features, merits, and demerits. We further discuss application of the digital assay in absolute nucleic acid quantification. Both the classic and recent microfluidics-based commercial molecular diagnostic devices are summarized as proof of the current market status. Finally, we propose future directions for microfluidics-based infectious disease diagnosis.

Here, we describe the optimization, synthesis, and associated pharmacological analgesic activities of a new series of bifunctional piperidinamide derivatives as sigma-1 receptor (σ

Microfluidic chip electrophoresis has been widely employed for separation of various biochemical species owing to its advantages of low sample consumption, low cost, fast analysis, high throughput, and integration capability. In this article, we reviewed the development of four different modes of microfluidics-based electrophoresis technologies including capillary electrophoresis, gel electrophoresis, dielectrophoresis, and field (electric) flow fractionation. Coupling detection schemes on microfluidic electrophoresis platform were also reviewed such as optical, electrochemical, and mass spectrometry method. We further discussed the innovative applications of microfluidic electrophoresis for biomacromolecules (nucleic acids and proteins), biochemical small molecules (amino acids, metabolites, ions, etc.), and bioparticles (cells and pathogens) analysis. The future direction of microfluidic chip electrophoresis was predicted.

Untethered small actuators have various applications in multiple fields. However, existing small-scale actuators are very limited in their intractability with their surroundings, respond to only a single type of stimulus and are unable to achieve programmable structural changes under different stimuli. Here, we present a multiresponsive patternable actuator that can respond to humidity, temperature and light, via programmable structural changes. This capability is uniquely achieved by a fast and facile method that was used to fabricate a smart actuator with precise patterning on a graphene oxide film by hydrogel microstamping. The programmable actuator can mimic the claw of a hawk to grab a block, crawl like an inchworm, and twine around and grab the rachis of a flower based on their geometry. Similar to the large- and small-scale robots that are used to study locomotion mechanics, these small-scale actuators can be employed to study movement and biological and living organisms., Untethered small actuators have various applications but existing small-scale actuators are limited in their response to different stimuli. Here, we present a multiresponsive patternable actuator that can respond to humidity, temperature and light, via programmable structural changes.

In the past few decades, protein-templated fluorescent gold nanoclusters have attracted much attention in the field of biosensing as their excellent optical properties and good biocompatibility. In this work, a fluorescence turn-on biosensor was fabricated for the sensitive detection of 5-hydroxytryptamine (5-HT) with transferrin encapsulated gold nanoclusters (Tf-Au NCs). The Tf-Au NCs were facilely prepared with the assistance of microwave radiation in several minutes and exhibited good monodispersity as well as strong red-emission. It was demonstrated that an aggregation-enhanced emission of Tf-Au NCs was triggered by 5-HT due to the high affinity between 5-HT and the sialic acid (SA) residues of transferrin. Based on these findings, a highly selective turn-on fluorescent sensor was fabricated for the quantitative determination of 5-HT in the range of 0.2–50 μM (R2 = 0.994) with a detection limit of 0.049 μM (S/N = 3). The developed sensor was also successfully applied for the 5-HT detection in human serum with satisfactory recoveries of 96.20–108.6%.

Hydrodynamic flow focusing-based micromixers (laminar micromixers) have been widely applied to the investigation of the folding kinetics of biomacromolecules, due to their capability to resolve the folding events in a microsecond time scale. Although most existing laminar micromixers attempted to reduce mixing time, our work focused on developing a system that can generate high-resolution images under a more stable flow, which results in more accurate kinetic analysis. Specifically, we developed a simple three-dimensional (3D) laminar micromixer, which distributes the sample stream to a 3D profile to address flow-instability issues caused by Dean vortices in a two-dimensional mixer. In the 3D mixer, the sample stream was successfully focused to a one-pixel width at the resolution of ˜200 nm/pixel, which approached the resolving power of an optical microscope and represented the highest imaging resolution ever achieved using a 3D mixer. Furthermore, we used the device to investigate the early folding kinetics of G-quadruplex under various sodium cation concentrations. Interestingly, a lag phase was found before the exponential phase during the folding process. Moreover, we obtained the G-quadruplex’s observed kinetics of (1.51 ± 0.02) ×104 s−1, (1.68 ± 0.04) ×104 s−1 and (2.01 ± 0.02) ×104 s−1 at 50-, 100- and 200 mM NaCl, respectively.

Efficient sample pretreatment of N-glycans from glycoproteins is essential but challenging due to the limitations of existing tedious and laborious methods in N-glycomics. This study aimed to establish a filter-aided extraction method coupled with glycosylamine AQC labeling for a simple and rapid direct HPLC-FLD-based analysis of N-glycans. The developed method was demonstrated to be simpler and more sensitive compared to previous HILIC SPE purification method coupled with glycosylamine labeling. It has been validated with wild-type N-glycans from human transferrin and RNase B and then was successfully applied to investigate N-glycan profiles of the transferrin in human serum and a monoclonal antibody (mAb). Results showed good applicability of the method for complex samples. Additionally, this method is compatible with the replicate determination of N-glycan samples to assess the high-throughput analysis of glycan variability in mAb sample.