Electronic and Magnetic Properties of Hybrid Boron Nitride Nanoribbons and Sheets with 5–7 Line Defects

The first-principles calculations have been used to investigate the electronic and magnetic properties of hybrid boron nitride nanoribbons (BNNR) and sheets, which are constructed by the B-rich or N-rich grain boundaries (GB) with the pentagon–heptagon (5–7) line defect joining together the normal zigzag and armchair BN segments. Our results show that, in contrast to the pristine BN systems, the hybrid BN nanostructures with 5–7 line defects possess some unique electronic and magnetic properties. The hybrid BNNR with H-passivated edge and BN sheet are semiconductors with notably reduced band gap due to the presence of line defect state, as compared to the normal BN systems. The band gaps of H-passivated hybrid BNNR with B-rich and N-rich GB exhibit the different variation with the ribbons width. The hybrid BNNR created by B-rich GB with bare N edge for all widths are half-semiconductors with the ferromagnetic ground state, whereas for the hybrid BNNR with bare zigzag B edge the antiferromagnetic → nonmagnetic semiconductor transition occurred when its narrow zigzag segment is changed to the wider one. Interestingly, totally different from the perfect zigzag BNNR, the hybrid BNNR with two-H-terminated B edge exhibit the metallic → half-semiconducting → half-metallic behavior transitions as its number of zigzag BN chains gradually increases due to the compressed zigzag edge. Therefore, the hybrid BN nanostructures constructed by GB with 5–7 line defects may provide potential applications for BN-based nanoelectronic and spintronic devices

Template Synthesis of Subnanometer Gold Clusters in Interfacially Cross-Linked Reverse Micelles Mediated by Confined Counterions

A cationic surfactant with a triallylammonium headgroup was cross-linked photochemically in the presence of a hydrophilic dithiol in the reverse micelle (RM) configuration. The interfacially cross-linked reverse micelles (ICRMs) are unusual templates for nanomaterials synthesis. Our previous work indicated that the ICRMs could extract anionic metal salts such as tetracholoroaurate into the hydrophilic interior, and the entrapped aurate was reduced without externally added reducing agent to form subnanometer luminescent gold clusters [Zhang, S.; Zhao, Y. <i>ACS Nano</i> <b>2011</b>, <i>5</i>, 2637–2646]. In this work, the bromide counterions were established as the reducing agent in the template synthesis. The reduction of tetrachloroaurate was proposed to happen through ligand exchange on the aurate by the bromide ions, reductive elimination of halogen, and disproportionation of the Au­(I) intermediate. The size of the gold clusters could be tuned rationally by the water-to-surfactant ratio (<i>W</i>₀) and the reducing agent. Monodisperse Au₄ and Au_9–10 clusters as well as larger Au₁₈ and Au₂₃ clusters were obtained from the ICRM templates. The as-prepared, metastable gold clusters were subject to reconstruction triggered by ligand exchange on the surface but could be stabilized through proper surface protection using a chelating dithiol

Nanodrug Hijacking Blood Transferrin for Ferroptosis-Mediated Cancer Treatment

Ferroptosis as a promising method of cancer treatment heavily relies on the intracellular iron ion level. Herein, a new iron-supplement nanodrug was developed by conjugating transferrin-homing peptide T10 on the surface of cross-linked lipoic acid vesicles (T10@cLAV), which could hijack blood transferrin (Tf) and specifically deliver it to tumor cells to elevate the Fe2+ level. Meanwhile, the intracellular degradation product of cLAV, dihydrolipoic acid, could regenerate Fe2+ to further boost the ferroptosis. The results disclosed that T10@cLAV achieved tumor inhibition comparable to that of cisplatin at a dose as low as 5 mg/kg in the HeLa tumor-bearing nude mice model and caused no toxicity at the dose up to 300 mg/kg. This tactful iron-supplement strategy of hijacking blood Tf is superior to the current strategies: one is the induction of intracellular ferritin degradation, which is limited by the low content of ferritin, and the other is the delivery of iron-based materials, which easily causes adverse effects

Superamphiphile Based Cross-Linked Small-Molecule Micelles for pH-Triggered Release of Anticancer Drugs

A new superamphiphile based cross-linked small-molecule micelle (SA-CSM) is developed for pH-triggered release of anticancer drugs. This strategy revolves around the use of a noncovalent superamphiphile formed by the elaborate zwitterion <b>1</b> and anticancer drug doxorubicin (DOX) via their “spontaneous attraction” of carboxylic acid and amino group. The superamphiphiles self-assemble into micelles in water, which were further stabilized by cross-linking the surface via the thiol-acrylate Michael addition to achieve the establishment of the pH-sensitive SA-CSMs. The biological evaluation shows that the new drug delivery system exhibits highly efficient anticancer efficacy both <i>in vitro</i>, on the HeLa cancer cell line, and <i>in vivo</i>, on the HeLa xenograft model, while suppressing the inherent toxicity of the employed chemotherapeutics. Compared with the reported covalent amphiphile based CSMs, the noncovalent superamphiphile based CSMs not only have comparable drug loading content (up to 45.0%), robust stability, and superior predictable biosafety but also feature nonchemical synthesis, low production cost, specific stimulus response, and anticancer activity of the original drugs and thus represent a good example for clinical application

Latent Naphthalimide Bearing Water-Soluble Nanoprobes with Catechol–Fe(III) Cores for in Vivo Fluorescence Imaging of Intracellular Thiols

Here, a novel latent naphthalimide bearing water-soluble nanoprobes with catechol–Fe­(III) cores (<b>Fe@LNNPs</b>) was designed, synthesized, and evaluated for in vivo fluorescence imaging of intracellular thiols, as various diseases are associated with overexpression of cellular biothiols. The <b>Fe@LNNPs</b> are mainly composed of three components. The inner part constitutes pyrocatechol groups, which can coordinate with Fe­(III) to form a cross-linked core for improving the stability in the complex biological environment. The naphthalimide group is linked by disulfide with the core to quench the probe fluorescence. The outer part is designed to be a hydrophilic glycol corona for prolonging blood circulation. Also, a biotin group can be easily introduced into the nanoprobe for actively targeting the HepG2 cells. The fluorescence spectra reveals that the <b>Fe@LNNPs</b> can be reduced explicitly by glutathione to trigger the fluorescence emission. Confocal microscopic imagings and animal experiments manifest that the <b>Fe@LNNPs</b>, especially with biotin groups, have much better fluorescence signal imaging compared to the reported small-molecule probe <b>1′</b> both in vitro and in vivo (up to 24 h). The <b>Fe@LNNPs</b> thus feature great advantages such as specificity, stability, biocompatibility, and long retention time for thiol-recognition imaging and hold potential applications in clinical cancer diagnosis

Cross-Linked Small-Molecule Micelle-Based Drug Delivery System: Concept, Synthesis, and Biological Evaluation

Lessons from the covalent capture of small-molecule self-assemblies (monomer molecular weight of <500.0) are applied to grow a generic cross-linked small-molecule micelle-based drug delivery system (CSM-DDS), which has significant advantages over the popular polymeric micelle-based drug delivery systems in terms of drug loading, stability, monomer purity, and cost of preparation. A proof-of-concept CSM-DDS constructed by one-step synthesized amphiphile <b>1</b> with anticancer drug gemcitabine confirms the feasibility of the new strategy via its high drug loading content (up to 58%), robust stability, superior predictable biosafety, facile functionalization, and remarkable anticancer activity both <i>in vitro</i> and <i>in vivo</i>

Tetraphenylethylene-Induced Cross-Linked Vesicles with Tunable Luminescence and Controllable Stability

Luminescence-tunable vesicles (LTVs) are becoming increasingly attractive for their potential application in optics, electronics, and biomedical technology. However, for real applications, luminous efficiency and durability are two urgent constraints to be overcome. Combining the advantages of aggregation-induced emission in luminous enhancement and cross-linking in stability, we herein fabricated tetraphenylethylene-induced cross-linked vesicles with an entrapped acceptor of RhB (TPE-CVs@RhB), which achieved a high-efficiency multicolor emission of the visible spectrum, including white, by altering the amount of entrapped acceptor. Stability tests show that the luminescence of TPE-CVs@RhB has excellent environmental tolerance toward heating, dilution, doping of organic solvent, and storage in serum. Further outstanding performance in the application of fluorescent inks suggests that the new LTVs hold high potential in industrialization. More attractively, although the TPE-CVs@RhB can tolerate various harsh conditions, their stability can actually be controlled through the cross-linker adopted. For example, the employment of dithiothreitol in the present work produces an acid-labile β-thiopropionate linker. The cellular uptake by HepG2 cells shows that the acid-labile TPE-CVs@RhB can effectively respond to the acidic environment of cancer cells and release the entrapped RhB molecules, indicative of promising applications of this new type of LTVs in bioimaging and drug delivery

Nanocopper-Doped Cross-Linked Lipoic Acid Nanoparticles for Morphology-Dependent Intracellular Catalysis

The metal catalysts encapsulated in nanomaterials have recently been applied successfully in bioorthogonal chemistry for intracellular generation of bioactive compounds. However, the nanomaterial-involved intracellular catalysis is intrinsically different from that in solution or in extracellular fluid. Except for the reactivity of metal catalyst itself, the supporting material’s morphology and biocompatibility are essential factors for building optimal nanocatalysts. Herein, we present a new nanocopper-doped cross-linked lipoic acid nanoparticle (Cu@cLANP) that meets the stringent requirements for the intracellular nanocatalyst. It comes from endogenous lipoic acid and can easily achieve the morphology change by different reduction methods. The optimal rugbylike Cu@cLANPs <b>I</b> did show much better catalytic efficiency for intracellular azide–alkyne cycloaddition than that of the other two spherical nanocatalysts Cu@cLANPs <b>II</b> and <b>III</b>, hinting at the importance of nanoparticle morphology for the intracellular bioorthogonal transformation

Confined Pool-Buried Water-Soluble Nanoparticles from Reverse Micelles

With the special nature of confined water pools, reverse micelles (RMs) have shown potential for a wide range of applications. However, the inherent water insolubility of RMs hinders their further application prospect especially for applications related to biology. We present herein the first successful transformation of water-insoluble RMs into water-soluble nanoparticles without changing the confined aqueous interiors by hydrolysis/aminolysis of arm-cleavable interfacial cross-linked reverse micelles formed from diester surfactant <b>1</b>. The unique properties exhibited by the aqueous interiors of the resulting pool-buried water-soluble nanoparticles (PWNPs) were demonstrated both by the template synthesis of gold nanoparticles in the absence of external reductants and by the fluorescence enhancement of encapsulated thioflavin T (ThT). Importantly, the unique potential for PWNPs in biological applications was exemplified by the use of ThT@PWNPs and “cell targeted” ThT@PWNPs as effective optical imaging agents of living cells. This work conceptually overcomes the application bottleneck of RMs and opens an entry to a new class of functional materials

High-Density Dynamic Bonds Cross-Linked Hydrogel with Tissue Adhesion, Highly Efficient Self-Healing Behavior, and NIR Photothermal Antibacterial Ability as Dressing for Wound Repair

Multifunctional hydrogels with tissue adhesion, self-healing behavior, and antibacterial properties have potential in wound healing applications. However, their inefficient self-healing behavior and antibacterial agents can cause long-term cytotoxicity and drug resistance, considerably limiting their clinical use. Herein, we reported a PDA@LA hydrogel constructed by introducing polydopamine nanoparticles (PDA-NPs) into a high-density dynamic bonds cross-linked lipoic acid (LA) hydrogel that was formed by the polymerization of LA. Because of its rich carboxyl groups, the LA hydrogel could adhere firmly to various tissues. Owing to the high-density dynamic bonds, the cut LA hydrogel exhibited highly inefficient self-healing behavior and recovered to its uncut state after self-healing for 10 min. After the introduction of the PDA-NPs, the hydrogel was able to heat up to more than 40 °C to kill approximately 100% of the Escherichia coli and Staphylococcus aureus under near-infrared (NIR) laser, thus resisting wound infections. Because no toxic antibacterial agent was used, the PDA@LA hydrogel caused mild long-term cytotoxicity or drug resistance. Consequently, the adhesive, highly efficient self-healing, and NIR photothermal antibacterial PDA@LA hydrogel exhibits considerable potential for clinical use