Supramolecular hydrogels derived from natural biomolecules have promising applications for drug delivery due to their inherent biocompatibility and tunable responsiveness to various stimuli. However, conventional hydrogels only modulate the release kinetics roughly to achieve sustained drug release, exhibiting fast-then-slow release behavior without on/off control. Herein, a guanosine (G)-quartet·Na+-borate supramolecular hydrogel (GB hydrogel) cross-linked via a guanosine-borate diester and intertwined by G4-nanofibres formed by π-π stacking of G4-quartets stabilized by Na+ is developed for on-demand release of Acyclovir (Acv). This GB hydrogel is facilely prepared by a one-pot hierarchical assembly involving hydrogen bonds, dynamic borate ester bonds and cation coordination, which endow it with tunable mechanical properties, excellent self-healing properties and reversible degradation behavior in response to pH, glucose and ion concentration. Benefiting from that the guanosine analog Acv is able to assemble into a G4-quartet by replacing guanosine via reversible hydrogen bonding, the Acv-loaded GB hydrogel showed favorable stability in physiological medium without undesired release and achieved external stimulus-triggered on-demand release with switchable on/off control and tunable release kinetics. Moreover, the GB hydrogel also exhibited excellent in vitro and in vivo biocompatibility. Such a natural nucleoside-based supramolecular hydrogel with on-demand drug release, self-healing property, biodegradability and biocompatibility provides a precisely controlled paradigm to overcome early burst release behavior of conventional hydrogels for the development of injectable hydrogel delivery systems.A reliable and sensitive sensing of multiple foodborne pathogens is critical for timely diagnosis and human health. To meet this need, herein, we designed a sandwich immunoassay platform, using functionalized SERS probes and magnetic beads, for the interference-free simultaneous detection of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in food samples by surface-enhanced Raman scattering (SERS) technology. The signal of two SERS probes coded by triple bonds (C[triple bond, length as m-dash]C and C[triple bond, length as m-dash]N) located at 2105 and 2227 cm-1, respectively, could perfectly avoid the spectral overlap with coexisting materials in the Raman fingerprint region, which ensured the accuracy of the immunoassay platform. The application of functional magnetic beads, integrating enrichment and separation, greatly improved the sensitivity of the detection system. Under magnetic force, due to the mature interaction between the antigen and antibody, the sandwich immunoassay platform could be fabricated. Its limit of detection (LOD) for the simultaneous detection of E. coli and S. aureus was as low as 10 and 25 cfu mL-1, respectively, and the sandwich immunoassay platform was successfully applied for the detection of E. coli and S. aureus in bottled water and milk. As a sensitive and highly selective analytical technique for the simultaneous multiple detection of pathogens, this SERS-based method has great potential to be applied in the field of food safety.Gold-sputtered microelectrodes with built-in gold reference and counter electrodes represent a promising platform for the development of disposable DNA sensors. Pretreating gold electrode surfaces and immobilization of DNA thereon is commonly employed in biosensing applications. However, with no scientific or practical guidelines to prepare a DNA sensor using these miniature gold-sputtered microelectrodes, cleaning and immobilization steps need to be systematically optimized and updated. In this work, we present efficient cleaning and modification of miniaturized gold-sputtered microelectrodes with thiolated DNA probes for DNA detection. Additional discussions on subtleties and nuances involved at each stage of pretreating and modifying gold-sputtered microelectrodes are included to present a robust, well-founded protocol.  https://www.selleckchem.com/products/GDC-0449.html  It was evident that the insights on cleaning polycrystalline gold disk electrodes with a benchmark electrode surface for DNA sensors, cannot be transferred to clean these miniature gold-spu and counter electrodes for both fundamental investigations and practical DNA sensing applications.Inflammation is a complex biological response of the human body to external or internal stimuli, such as invading pathogens, defective cells, or irritating substances. One important indicator of inflammatory conditions or the progress of various diseases, such as cancer, cardiovascular diseases, neurological diseases, connective tissue diseases, sepsis, or Alzheimer's disease, is the concentration level of inflammatory biomarkers, including immunoglobulins, cytokines, and C-reactive protein (CRP). Since inflammatory biomarkers are highly correlated with each other, it is important to measure them simultaneously. To enable continuous and dynamic inflammatory biomarker detection, we utilized localized surface plasmon resonance (LSPR) to perform label-free molecule sensing. Since the LSPR sensing mechanism requires only a small sensing area with simplified optical setup, it can be easily integrated with a microfluidic device. To simplify reagent operation complexity, we developed an automated microfluidic control system to control reagent guiding and switching in the immunoassay with less manual processes and potential operation errors. Our results successfully demonstrated multiplex IgG, TNF-α, and CRP measurement with only 60 μL assay volume and 3.5 h assay time. In each test, 20 sensing spot measurements under four different reagent conditions can be performed. Overall, we envision that the LSPR sensor integrated automated microfluidic control system could perform rapid, multiplex, and multiparallel continuous inflammatory biomarker detection, which would be beneficial for various applications, such as immune status monitoring, diagnosis and prognosis of inflammatory diseases.Molybdenum disulfide (MoS2) is one of the two-dimensional layered semiconductor transition metal dichalcogenides (TMDCs) with great potential in electronics, optoelectronics, and spintronic devices. Sulfur vacancies in MoS2 are the most prevalent defects. However, the effect of sulfur vacancies on the electronic structure of MoS2 is still in dispute. Here we experimentally and theoretically investigated the effect of sulfur vacancies in MoS2. The vacancies were intentionally introduced by thermal annealing of MoS2 crystals in a vacuum environment. Angle-resolved photoemission spectroscopy (ARPES) was used directly to observe the electronic structure of the MoS2 single crystals. The experimental result distinctly revealed the appearance of an occupied defect state just above the valence band maximum (VBM) and an upward shift of the VBM after creating sulfur vacancies. In addition, density functional theory (DFT) calculations also confirmed the existence of the occupied defect state close to the VBM as well as two deep unoccupied states induced by the sulfur vacancies.