Dynamically Cross-linked Elastomer Hybrids with Light-Induced Rapid and Efficient Self-Healing Ability and Reprogrammable Shape Memory Behavior

Pristine carbon nanotubes (CNTs) were activated to exhibit Diels–Alder (DA) reactivity in a polymer matrix, which was modified with monomers containing furan groups. The DA-active polymer matrix was transferred into a dynamic reversible cross-linked inorganic–organic network via a Diels–Alder reaction with CNTs, where pristine CNTs were used as dienophile chemicals and furan-modified SBS acted as the macromolecular diene. In this system, the mechanical properties as well as resilience and solvent resistance were greatly improved even with the presence of only 1 wt % CNTs. Meanwhile, the hybrids retained recyclability and exhibited some smart behaviors, including self-healing and reprogrammable shape memory properties. Furthermore, due to the photothermal effect of CNTs, a retro-Diels–Alder (rDA) reaction was activated under laser irradiation, and healing of a crack on the hybrid surface was demonstrated in approximately 10 s with almost complete recovery of the mechanical properties. Such fast and efficient self-healing performance provides a new concept in designing self-healing nanocomposites with tunable structures and mechanical properties. Furthermore, the DA and rDA reactions could be combined to reprogram the shape memory behavior under laser irradiation or thermal treatment, wherein the temporary shape of the sample could be transferred to a permanent shape via the rDA reaction at high temperature

Shape Memory: An Efficient Method to Develop the Latent Photopatterned Morphology for Elastomer in Two/Three Dimension

Shape memory behavior was applied here as a new approach for developing the latent photopatterned morphologies in two/three dimension (2D/3D) on the modified poly­(styrene-<i>block</i>-butadiene-<i>block</i>-styrene) (SBS). By attaching anthracene groups onto the SBS chains, the elastomer frozen in the deformed state was photopatterned via the photodimerization of anthracene. Upon thermal treatment, shape memory process could effectively develop the latent photopatterning induced 2D–2D and 2D–3D shape transformation. Due to the reversible dimerization of anthracene, the photoinduced patterns and the shape conformation could be erased and redeveloped for multiple times

A Facile One-Pot Synthesis of Copper Sulfide-Decorated Reduced Graphene Oxide Composites for Enhanced Detecting of H₂O₂ in Biological Environments

The high levels of H₂O₂ are closely associated with cancer and progressive neurodegenerative diseases, such as Parkinson’s disease. In this study, we developed a novel CuS nanoparticle-decorated reduced graphene oxide-based electrochemical biosensor for the reliable detection of H₂O₂. The new electrocatalyst, CuS/RGO composites was successfully prepared by heating the mixture of CuCl₂ and Na₂S aqueous solutions in the presence of PVP-protected graphene oxide at 180 °C. A potential application of CuS/RGO composite-modified electrode as a biosensor to monitor H₂O₂ has been investigated. The steady-state current response increases linearly with H₂O₂ concentration from 5 to 1500 μM with a fast response time of less than 2 s. The detection limit (3σ) for determination of H₂O₂ has been estimated to be 0.27 μM, which was lower than certain enzymes and noble metal nanomaterial-based biosensors. In addition, the study of storage time on the amperometric response of the sensor indicates super stability. Due to these remarkable analytical advantages, the as-made sensor was applied to determine the H₂O₂ levels in human serum and urine samples and H₂O₂ released from human cervical cancer cells with satisfactory results. These results demonstrate that this new nanocomposite with the high surface area and electrocatalytic activity is a promising candidate for use as an enhanced electrochemical sensing platform in the design of nonenzymatic biosensors

Impact of Shape and Pore Size of Mesoporous Silica Nanoparticles on Serum Protein Adsorption and RBCs Hemolysis

With the rapid development of nanotechnology, mesoporous silica nanoparticles (MSNs) with numerous forms and structures have been synthesized and extensively applied in biomedicine in the past decades. However, our knowledge about the biocompatibility of the developed MSNs has not matched their development. Therefore, in this work, we have synthesized sphere-shaped MSNs with different pore scales (<i>s</i>-SPs and <i>l</i>-SPs) and rod-shape (RPs-3) MSNs to evaluate the influence of the morphology and pore size on their interaction with serum proteins and red blood cells (RBCs). The adsorption of human albumin (HSA), globulin (HGG), and fibrinogen (HSF) onto different kinds of MSNs has been analyzed by pseudo second-order kinetic model, and the conformational changes of the adsorbed proteins have been studied by FTIR spectroscopy. We find that the conformation of absorbed HSA and HSF, while not HGG, will be affected by the pore size and morphology of the MSNs. The conformational changes of the adsorbed proteins will further affect their saturated adsorption capacity. However, the initial adsorption rate is only determined by the property of MSNs and proteins. Additional hemolysis assay shows that the pore size and morphology of the MSNs will also affect their hemolytic activity in RBCs which will be extremely depressed by the formation of protein corona. These systematic studies will provide an overall understanding in the blood compatibility of MSNs as well as useful guidelines for fabrication of blood-compatible nanomaterials

Chromium-Catalyzed Asymmetric Dearomatization Addition Reactions of Halomethyl Heteroarenes

The first asymmetric dearomatization addition reaction of halomethyl arenes including benzofuran and benzothiophene was enabled by chromium catalysis. A variety of aldehydes served as suitable electrophiles under mild reaction conditions. Molecular complexities are quickly increased in a highly diastereo- and enantioselective manner

ZnO/CoO and ZnCo₂O₄ Hierarchical Bipyramid Nanoframes: Morphology Control, Formation Mechanism, and Their Lithium Storage Properties

Mastery over the structure of nanoscale materials can effectively tailor and regulate their electrochemical properties, enabling improvement in both rate capability and cycling stability. We report the shape-controlled synthesis of novel mesoporous bicomponent-active ZnO/CoO hierarchical multilayered bipyramid nanoframes (HMBNFs). The as-synthesized micro/nanocrystals look like multilayered bipyramids and consist of a series of structural units with similar frames and uniform sheet branches. The use of an appropriate straight-chain monoalcohol was observed to be critical for the formation of HMBNFs. In addition, the structure of HMBNFs could be preserved only in a limited range of the precursor ratio. An extremely fast crystal growth process and an unusual transverse crystallization of the ZnCo-carbonate HMBNFs were newly discovered and proposed. By calcination of ZnCo-carbonate HMBNFs at the atmosphere of nitrogen and air, ZnO/CoO and ZnCo₂O₄ HMBNFs were obtained, respectively. Compared to the ZnCo₂O₄ HMBNFs, the ZnO/CoO HMBNFs with a uniform distribution of nanocrystal ZnO and CoO subunits exhibited enhanced electrochemical activity, including greater rate capability and longer cycling performance, when evaluated as an anode material for Li-ion batteries. The superior electrochemical performance of the ZnO/CoO HMBNFs is attributed to the unique nanostructure, bicomponent active synergy, and uniform distribution of ZnO and CoO phases at the nanoscale

Cellular Uptake of Nanoparticles by Membrane Penetration: A Study Combining Confocal Microscopy with FTIR Spectroelectrochemistry

It is well-known that nanomaterials are capable of entering living cells, often by utilizing the cells’ endocytic mechanisms. Passive penetration of the lipid bilayer may, however, occur as an alternative process. Here we have focused on the passive transport of small nanoparticles across the plasma membranes of red blood cells, which are incapable of endocytosis. By using fluorescence microscopy, we have observed that zwitterionic quantum dots penetrate through the cell membranes so that they can be found inside the cells. The penetration-induced structural changes of the lipid bilayer were explored by surface-enhanced infrared absorption spectroscopy and electrochemistry studies of model membranes prepared on solid supports with lipid compositions identical to those of red blood cell membranes. A detailed analysis of the infrared spectra revealed a markedly enhanced flexibility of the lipid bilayers in the presence of nanoparticles. The electrochemistry data showed that the overall membrane structure remained intact; however, no persistent holes were formed in the bilayers

Additional file 1: of Bibliometric study of research and development for neglected diseases in the BRICS

Multilingual abstracts in the five official working languages of the United Nations. (PDF 185 kb

The representive GC-MS spectra of L-Alanine derived from total ion chromatograms.

<p>Culture medium (black), untreated cells (red), <i>R</i>-Carvedilol-treated cells (green) and <i>S</i>-Carevdilol-treated cells (blue).</p

Fabrication of Multifunctional SiO₂@GN-Serum Composites for Chemo-Photothermal Synergistic Therapy

Recently, the chemo-photothermal synergistic therapy has become a potential method for cancer treatment. Herein, we developed a multifunctional nanomaterial for chemo-photothermal therapeutics based on silica and graphene core/shell structure (SiO₂@GN) because of the ability of GN to convert light energy into heat. Serum protein was further modified onto the surface of GN (SiO₂@GN-Serum) to improve the solubility and stability of GN-based nanoparticles in physiological conditions. The as-synthesized SiO₂@GN-Serum nanoparticles (NPs) have been revealed to have high photothermal conversion efficiency and stability, as well as high storage and release capacity for anticancer drug doxorubicin (SiO₂@GN-Serum-Dox). The therapeutic efficacy of SiO₂@GN-Serum-Dox has been evaluated in vitro and in vivo for cervical cancer therapy. In vitro cytotoxicity tests demonstrate that SiO₂@GN-Serum NPs have excellent biocompatibility. However, SiO₂@GN-Serum-Dox NPs show higher cytotoxicity than SiO₂@GN-Serum and free Dox under irradiation with NIR laser at 1.0 W/cm² for 5 min owing to both SiO₂@GN-Serum-mediated photothermal ablation and cytotoxicity of light-triggered Dox release. In mouse models, the tumor growth is significantly inhibited by chem-photothermal effect of SiO₂@GN-Serum-Dox. Overall, compared with single chemotherapy or photothermal therapy, the combined treatment demonstrates better therapeutic efficacy. Our results suggest a promising GN-based core/shell nanostructure for biomedical applications