The Royal Society of Chemistry最新文献

Reactive oxygen and nitrogen species (ROS/RNS) in macrophages have a potent killing effect on pathogens that infect the host. Here, we achieved in situ, quantitative detection of the homeostasis of four primary ROS/RNS (ONOO^-, H₂O₂, NO, and NO₂^-) and their precursors (O₂˙^-, NO) in phagolysosomes of single RAW 264.7 macrophages after phagocytosis of Escherichia coli with platinum-black nanoelectrodes. Enhanced bactericidal activity of the macrophages was observed by an increase in the total amount of ROS/RNS as well as the level and proportion of ONOO^-, a potent bactericidal species of RNS. Moreover, both the bactericidal process and the steady-state replenishment process were dominated by the production of RNS (NO-based), revealing differences in the enzyme kinetics of the bactericidal process.

In this contribution, a novel, simple, diastereoselective and environmentally benign two-step diversity-oriented synthesis of imidazo[4,5,1-ij]quinolines is described for the first time. The synthesis of the target compounds involves a deep eutectic solvent-mediated one-pot Povarov reaction leading to the obtention of 8-nitrotetrahydroquinolines, followed by a microwave-assisted reductive cyclocondensation employing different aromatic and aliphatic aldehydes. The target compounds were obtained in up to 70% overall yield starting from commercially available o-nitroanilines, natural phenylpropanoids (trans-anethole and trans-isoeugenol) and aromatic or aliphatic aldehydes. The eutectic solvent employed in the first step was reused in four runs without observing a drastic decrease in catalytic activity, and sodium dithionite showed to be an efficient and green reducing agent for the second step. This methodology provides significant advantages in terms of synthetic and green chemistry such as mild reaction conditions, short reaction time, energy-efficiency, simple work-up procedure, low cost, scalability and utilization of renewable substrates and a reusable solvent.

We use lattice-Boltzmann molecular dynamics (LBMD) simulations to study the compression of a confined polymer immersed in a fluid and pushed by a large spherical colloid with a diameter comparable to the channel width. We examined the chain's deformation with both purely repulsive and weakly attractive Lennard-Jones (LJ) potentials applied between the monomers. The sphere's velocity was varied over 3 orders of magnitude. The chain is in a non-dense state at low pushing velocities for both repulsive and attractive monomer interactions. When the velocity of the spherical colloid exceeds a threshold v*, the back end of the chain transitions to a high density state with low mean square monomer displacement (MSD) values. The front end, however, remains in a non-dense state with high MSD indicating a pseudo two-state coexistence. This crossover is also revealed through volume per monomer and MSD as a function of the sphere's velocity. We also studied polymer dynamics by investigating folding events at different times.

Trilayer electrochemical actuators comprising an electrolyte layer sandwiched between two electrode layers have been shown to exhibit large deformations at low actuation voltages. Here we report the aerosol-jet printing (AJP) of high-aspect-ratio bending-type trilayer electrochemical microactuators comprised of Nafion as the electrolyte and poly(3,4-ethylenedioxythiophene)polystyrene sulfonate (PEDOT:PSS) as the electrode. We investigated how the thicknesses of the electrolyte and electrode layers affect the DC response of these actuators by fabricating high-aspect-ratio trilayer cantilevers with varied layer thicknesses (0.36 μm to 1.9 μm-thick electrodes, and 3.5 μm to 12 μm-thick electrolyte layers). We found that the transported charge and angular deflection are proportional to the applied voltage at steady state, and the charge-to-voltage ratio scales with the PEDOT:PSS thickness. The deflection-to-voltage ratio is found to be strongly affected by the Nafion electrolyte thickness, showing a decreasing trend, but is less affected by the PEDOT:PSS thickness in the range of dimensions fabricated. The timescales for deflection are found to be generally longer than the timescales for charge transfer and no clear trend is observed with respect to layer thicknesses. This work establishes an experimental protocol in geometry optimisation of printed electrochemical microactuators, verifies the applicability of a theoretical model, and lays the groundwork for designing and optimising more sophisticated printed electrochemical microactuation systems.

Correction for 'Controllable biomolecule release from self-assembled organic nanotubes with asymmetric surfaces: pH and temperature dependence' by Naohiro Kameta et al., Soft Matter, 2008, 4, 1681-1687, https://doi.org/10.1039/B803742F.

The synthesis and biological evaluation of 17(R/S)-Me-RvD5_{n-3 DPA}, an analog of the specialized pro-resolving mediators RvD5 and RvD5_{n-3 DPA}, are presented. The synthesis was successfully accomplished utilizing Midland Alpine borane reduction, Sonogashira cross-coupling and a one-pot hydrozirconation/iodination protocol. In vivo evaluation of RvD5, RvD5_{n-3 DPA} and 17(R/S)-Me-RvD5_{n-3 DPA} in a mouse model of fracture revealed that all three compounds inhibited postoperative pain in male mice, but not in female mice.

Traditional hydrogels based on Schiff base reactions frequently encounter issues with rapid drug release when employed as drug delivery systems owing to their susceptibility to hydrolysis under acidic conditions. It is, therefore, necessary to implement improvements to regulate the drug release behavior. In this study, a dual-network and pH-responsive biopolysaccharide hydrogel was developed, which is self-healing, injectable and biocompatible. Most importantly, the hydrogel has excellent tunability for controlled drug release. The hydrogel consisted of a primary network of dibenzaldehyde-functionalized poly(ethylene glycol) (DP) and chitosan (CS) formed through a Schiff base reaction and a secondary network of sodium alginate (SA) and CS formed through electrostatic interactions. It was found that the DP–CS–2%SA hydrogel can prolong the release duration up to four-fold compared to the single-network DP–CS hydrogel at a given release threshold. Significantly, by adjusting the relationship between the two effects through the amount of SA, the release modifiability of drug delivery systems has been greatly enhanced. This study could significantly enhance the tunability of hydrogel drug delivery systems.

Nanozymes are nanomaterials with catalytic properties similar to enzymes and offer advantages over natural enzymes such as lower cost, ease of storage, and convenience for large-scale preparation. Thus, they have received increasing attention and are extensively applied in fields such as chemistry, sensing, food, environment, and medicine. Herein, a hemin-derived nanozyme (Hemin-CDs) was prepared using hemin as the precursor and used to substitute the natural horseradish peroxidase (HRP) for colorimetric detection. The prepared Hemin-CDs exhibit excellent water dispersibility, stability and superior peroxidase-like activity. They catalyze the oxidative coupling of colorless 4-aminoantipyrine (4-AAP) with N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methylaniline sodium salt (TOOS) in the presence of H₂O₂, forming a purple quinone diimine dye with an absorption peak at 554 nm, which enables the quantification of H₂O₂ by measuring the absorbance. Quantitative detection of glucose was further demonstrated under physiological conditions. The detection of H₂O₂ and glucose takes only 10 minutes, with linear ranges of 1-150 μM and 2.5-300 μM, and LODs of 0.867 μM and 1.026 μM, respectively. Glucose in human serum was successfully detected with satisfactory recoveries (87.5-104.0%). Furthermore, a test strip was developed, and a smartphone was utilized to recognize the color of the test position, enabling rapid and accurate quantification of glucose concentrations within 5 minutes, which promises to enhance the accessibility and convenience of glucose testing.

We present a novel DNA molecular machine (RCA-D-Walker) that integrates a DNAzyme-based molecular beacon with RCA-based vectors for miRNA imaging in tumor cells. It can accurately target tumor cells through the sgc8 aptamer. The target miRNA can restore the DNAzyme's ability to cleave the substrate, which in turn produces an amplified fluorescent signal. The RCA-D-Walker exhibits enhanced tumor cell targeting, improved cell permeability, and greater resistance to nuclease degradation. Utilizing this strategy, we achieved accurate and efficient imaging of miRNA-21 in tumor cells.

Tumor organoids present a challenge in drug screening due to their considerable heterogeneity in morphology and size. To address this issue, we proposed a portable microfluidic device that employs image processing algorithms for specific target organoid recognition and microvalve-controlled deflection for sorting and collection. This morphology-activated organoid sorting system offers numerous advantages, such as automated classification, portability, low cost, label-free sample preparation, and gentle handling of organoids. We conducted classification experiments using polystyrene beads, F9 tumoroids and patient-derived tumor organoids, achieving organoid separation efficiency exceeding 88%, purity surpassing 91%, viability exceeding 97% and classification throughput of 800 per hour, thereby meeting the demands of clinical organoid medicine.