RuO2-Incorporated Co3O4 Nanoneedles Grown on Carbon Cloth as Binder-Free Integrated Cathodes for Tuning Favorable Li2O2 Formation.

Developing ideal Li-O2 batteries (LOBs) requires the discharge product to have a large quantity, have large contact area with the cathode, and not passivate the porous surface after discharge, which put forward high requirement for the design of cathodes. Herein, combining the rational structural design and high activity catalyst selection, minor amounts of RuO2-incorporated Co3O4 nanoneedles grown on carbon cloth are successfully synthesized as binder-free integrated cathodes for LOBs. With this unique design, plenty of electron-ion-oxygen tri-phase reaction interface is created, the side reaction from carbon is isolated, and oxygen reduction reaction/oxygen evolution reaction (OER) kinetics are significantly facilitated. Upon discharge, film-like Li2O2 is observed growing on the needle surface first and eventually ball-like Li2O2 particles form at each tip of the needle. The cathode surface remains porous after discharge, which is beneficial to the OER and is rare in the previous reports. The battery exhibits a high specific discharge capacity (7.64 mAh cm-2) and a long lifespan (500 h at 0.1 mA cm-2). Even with a high current of 0.3 mA cm-2, the battery achieves a cycling life of 200 h. In addition, punch-type LOBs are fabricated and successfully operated, suggesting that the cathode material can be utilized in ultralight, flexible electronic devices.

Two-Pronged Intracellular Co-Delivery of Antigen and Adjuvant for Synergistic Cancer Immunotherapy.

Nanovaccines have emerged as promising alternatives or complements to conventional cancer treatments. Despite the progresses, specific co-delivery of antigen and adjuvant to their corresponding intracellular destinations for maximizing the activation of antitumor immune responses remains a challenge. Herein, a lipid-coated iron oxide nanoparticle is delivered as nanovaccine (IONP-C/O@LP) that can co-deliver peptide antigen and adjuvant (CpG DNA) into cytosol and lysosomes of dendritic cells (DCs) through both membrane fusion and endosome-mediated endocytosis. Such two-pronged cellular uptake pattern enables IONP-C/O@LP to synergistically activate immature DCs. Iron oxide nanoparticle also exhibits adjuvant effects by generating intracellular reactive oxygen species, which further promotes DC maturation. IONP-C/O@LP accumulated in the DCs of draining lymph nodes effectively increases the antigen-specific T cells in both tumor and spleen, inhibits tumor growth, and improves animal survival. Moreover, it is demonstrated that this nanovaccine is a general platform of delivering clinically relevant peptide antigens derived from human papilloma virus 16 to trigger antigen-specific immune responses in vivo.

Fabrication of Large Single Crystals for Platinum-Based Linear Polymers with Controlled-Release and Photoactuator Performance.

Preparation of large single crystals of linear polymers for X-ray analysis is very challenging. Herein, we employ a coordination-driven self-assembly strategy to secure the appropriate head-to-tail alignment of anthracene moieties, and for the first time obtained large-sized Pt-based linear polymer crystals through a [4+4] cycloaddition of anthracene in a single-crystal to single-crystal fashion. Using X-ray diffraction to determine the polymer crystal structure, we found that both the polymerisation and depolymerisation steps proceed via a stable intermediate. Taking advantage of the temperature-dependent slow depolymerization, the Pt-based linear polymer showed potential as a sustained release anticancer drug platform. Utilizing the reversible contraction effect of unit-cell volume upon irradiation or heating, the stimuli-responsive crystals were hybridized with polyvinylidene fluoride to obtain a "smart material" with outstanding photoactuator performance.

Photomechanical Organic Crystals as Smart Materials for Advanced Applications.

Photomechanical molecular crystals are receiving much attention due to their efficient conversion of light into mechanical work and advantages including faster response time; higher Young's modulus; and ordered structure, as measured by single-crystal X-ray diffraction. Recently, various photomechanical crystals with different motions (contraction, expansion, bending, fragmentation, hopping, curling, and twisting) are appearing at the forefront of smart materials research. The photomechanical motions of these single crystals during irradiation are triggered by solid-state photochemical reactions and accompanied by phase transformation. This Minireview summarizes recent developments in growing research into photoresponsive molecular crystals. The basic mechanisms of different kinds of photomechanical materials are described in detail; recent advances in photomechanical crystals for promising applications as smart materials are also highlighted.