Functional siRNAs are employed as cross-linkers to direct the self-assembly of DNA-grafted polycaprolactone (DNA-g-PCL) brushes to form spherical and nanosized hydrogels via nucleic acid hybridization in which small interfering RNAs (siRNAs) are fully embedded and protected for systemic delivery. Owing to the existence of multivalent mutual crosslinking events inside, the crosslinked nanogels with tunable size exhibit not only good thermostability, but also remarkable physiological stability that can resist the enzymatic degradation. As a novel siRNA delivery system with spherical nucleic acid (SNA) architecture, the crosslinked nanogels can assist the delivery of siRNAs into different cells without any transfection agents and achieve the gene silencing effectively both in vitro and in vivo, through which a significant inhibition of tumor growth is realized in the anticancer treatment.

The possibility and rate of charge separation (CS) in donor−bridge−acceptor molecules mainly depend on two factors: electronic coupling and solvent effects. The question of how CS occurred in two identical chromophores is fundamental, as it is particularly interesting for potential molecular electronics applications and the photosynthetic reaction centers (RCs). Conjugated bridge definitely plays a crucial role in electronic coupling. To determine the bridgemediated charge separation dynamics between the two identical chromophores, the isomeric N-annulated perylene diimide dimers (para-BDNP and meta-BDNP) with different conjugated bridge structures have been comparatively investigated in different solvents using femtosecond transient absorption spectra (fs-TA). It is found that the charge separation is disfavored in weak polar solvent, whereas direct spectroscopic signatures of radicals are observed in polar solvents, and the rate of charge separation increases as the solvent polarity increasing. To our surprise, the rate of charge separation in m-BDNP is more than an order of magnitude slower than that in p-BDNP, although there is a larger negative ΔG CS in m-BDNP. The slow CS rate that occurred in m-BDNP mainly results from the intrinsic destructive interference of the wave function through the meta-substituted bridge. The roles of solvent effects in free energy and electronic coupling for charge separation are further identified with quantum calculations.

A catalyst of palladium [Pd/MIL-101(Al)-NH 2 ] supported on amine-functionalized MetalOrganic Frameworks (MOFs) allows selective hydrogenation of biomass-based 5-hydroxymethylfurfural (HMF) to 2,5-dihydroxymethyl-tetrahydrofuran (DHMTHF) with 2,5-dihydroxymethylfuran (DHMF) as an observed "intermediate". The Pd/MIL-101(Al)-NH 2 was prepared by using a direct anionic exchange approach and subsequent gentle reduction. The presence of free amine moieties in the frameworks of MIL-101(Al)-NH 2 is suggested to play a key role on the formation of uniform and well-dispersed palladium nanoparticles on the support. The adsorption experiments reveal that the amine-functionalized MOF supports show preferential adsorption to hydrogenation intermediate DHMF than in the case of reactant HMF owing to an enhanced hydrophilic nature of DHMF as well as improved hydrogen bonding interactions between DHMF and the MOF support, which promotes a further hydrogenation of DHMF to DHMTHF upon the in situ formation of DHMF over Pd/MIL-101(Al)-NH 2 . Moreover, our results also indicate that the observed high selectivity towards DHMTHF form HMF is closely related to the cooperation between metallic site and free amine moiety on the MOF support. Under the optimal conditions, a maximum DHMTHF yield of 96% with a full conversion of HMF is obtained by using Pd/MIL-101(Al)-NH 2 (Pd 3.0 wt%) catalyst at a low reaction temperature of 30 °C in aqueous medium. The research thus highlights new perspectives for aluminum-based and amine-functionalized MOF material for biomass transformation.