Juenguo

Novel DNA-gated mesoporous silica nanoparticle (MSN) vehicles functionalized with disulfide-linked acridinamine intercalators are constructed for multi-responsive controlled release. The DNA-gated MSN vehicles release cargo encapsulated in the MSN pores under different stimuli, including disulfide reducing agents, elevated temperature, and deoxyribonuclease I (DNase I), for codelivery of drugs and DNA/genes in different forms. Furthermore, the cascade release of encapsulated and intercalative drugs is controlled by AND logic gates in combination of dual stimuli. The ingeniously designed DNA-gated MSN vehicles integrates multiple responses and AND logic gate operations into a single smart nanodevice not only for codelivery of drugs and DNA/genes but also for cascade release of two drugs and has promising biological applications to meet diverse requirements of controlled release.

A single smart nanodevice: Native DNA-gated mesoporous silica delivery vehicles functionalized with disulfide-linked acridinamine intercalators integrate multiple responses and “AND” logic gate operations not only for codelivery of encapsulated drugs and DNA/genes but also for cascade release of encapsulated and intercalative drugs and has promising biological applications to meet diverse requirements of controlled release.

A game of tag: N-Glycans on the surface of living cells were selectively tagged by exogenously administering recombinant ST6Gal I sialyltransferase and azide-modified CMP-Neu5Ac. This modification was followed by a strain-promoted cycloaddition using a biotin-modified dibenzylcyclooctynol (red star=biotin). The methodology will make it possible to dissect the mechanisms that underlie altered glycoconjugate recycling and storage in disease.

Golden times: Recent breakthroughs in gold-catalyzed transformations using nanosized homogeneous gold catalysts are highlighted. These catalysts have activities and stabilities comparable to (or even surpassing) heterogeneous catalysts. Well-defined, ligand-supported gold clusters turned out to be active in homogeneous catalysis, a catalyst concept which holds potential for future studies.

Blue emission at NIR excitation: A strategy, based on energy management in nanostructured materials, is reported for photon upconversion of near-infrared light. Several optical processes can be integrated into a single nanoparticle (see picture). The effect offers upconversion emissions spanning from ultraviolet to the visible spectral region by excitation at 808 nm.

The future perspective of fluorescence imaging for real in vivo application are based on novel efficient nanoparticles which is able to emit in the second biological window (1000–1400 nm). In this work, the potential application of Nd³⁺-doped LaF₃ (Nd³⁺:LaF₃) nanoparticles is reported for fluorescence bioimaging in both the first and second biological windows based on their three main emission channels of Nd³⁺ ions: ⁴F_3/2→⁴I_9/2, ⁴F_3/2→⁴I_11/2 and ⁴F_3/2→⁴I_13/2 that lead to emissions at around 910, 1050, and 1330 nm, respectively. By systematically comparing the relative emission intensities, penetration depths and subtissue optical dispersion of each transition we propose that optimum subtissue images based on Nd³⁺:LaF₃ nanoparticles are obtained by using the ⁴F_3/2→⁴I_11/2 (1050 nm) emission band (lying in the second biological window) instead of the traditionally used ⁴F_3/2→⁴I_9/2 (910 nm, in the first biological window). After determining the optimum emission channel, it is used to obtain both in vitro and in vivo images by the controlled incorporation of Nd³⁺:LaF₃ nanoparticles in cancer cells and mice. Nd³⁺:LaF₃ nanoparticles thus emerge as very promising fluorescent nanoprobes for bioimaging in the second biological window.

The future achievement of depth tissue real in vivo imaging requires the development of novel efficient infrared fluorescence nanoparticles. In this work, the potential application of Nd³⁺-doped LaF₃ nanoparticles is reported for fluorescence bioimaging based on their three main emission channels of Nd³⁺ ions (first and second biological windows). High contrast and low toxicity are obtained, both in vivo and in vitro, using 1.06 μm.

Graphene-based materials are useful reinforcing agents to modify the mechanical properties of hydrogels. Here, an approach is presented to covalently incorporate graphene oxide (GO) into hydrogels via radical copolymerization to enhance the dispersion and conjugation of GO sheets within the hydrogels. GO is chemically modified to present surface-grafted methacrylate groups (MeGO). In comparison to GO, higher concentrations of MeGO can be stably dispersed in a pre-gel solution containing methacrylated gelatin (GelMA) without aggregation or significant increase in viscosity. In addition, the resulting MeGO-GelMA hydrogels demonstrate a significant increase in fracture strength with increasing MeGO concentration. Interestingly, the rigidity of the hydrogels is not significantly affected by the covalently incorporated GO. Therefore, this approach can be used to enhance the structural integrity and resistance to fracture of the hydrogels without inadvertently affecting their rigidity, which is known to affect the behavior of encapsulated cells. The biocompatibility of MeGO-GelMA hydrogels is confirmed by measuring the viability and proliferation of the encapsulated fibroblasts. Overall, this study highlights the advantage of covalently incorporating GO into a hydrogel system, and improves the quality of cell-laden hydrogels.

Methacrylate is chemically grafted on the graphene oxide (GO) surface. Higher concentrations of the resulting methacrylated graphene oxide (MeGO) can be stably dispersed and conjugated within the hydrogels which improved fracture strength as compared with GO. In addition, cells maintain high viability within MeGO-linked hydrogels. Therefore, covalent incorporation of GO induces proper interfacial bonding between GO and the polymeric network, and ultimately improves the quality of cell-laden hydrogels.

Silicon nanocrystals (SiNCs) have received much attention because of their exquisitely tunable photoluminescent response, biocompatibility, and the promise that they may supplant their CdSe quantum dot counterparts in many practical applications. One attractive strategy that promises to extend and even enhance the utility of SiNCs is their incorporation into NC/polymer hybrids. Unfortunately, methods employed to prepare hybrid materials of this type from traditional compound semiconductor (e.g., CdSe) quantum dots are not directly transferable to SiNCs because of stark differences in surface chemistry. Herein, the preparation of chemically resistant SiNC/polystyrene hybrids exhibiting exquisitely tunable photoluminescence is reported and material processability is demonstrated by preparing micro and nanoscale architectures.

Highly luminescent, solution processable silicon nanocrystals/polystyrene hybrid materials are synthesized using size-independent radical-initiated hydrosilylation. Combining the properties of nanocrystals with polymer significantly increases solubility and processability, provides the opportunity to fabricate uniform nano- and microscale architectures, and renders silicon particles chemically resistant to prolonged exposure to strongly basic conditions.

The electrochromism and photothermoelectric properties of a poly(3,4-ethylenedioxyselenophene) derivative are investigated by precisely controlling the morphology and applied electrical potential of the flexible polymer films. On page 5483, Eunkyoung Kim and co-workers report a highly efficient and flexible photothermoelectric converter using doped poly(3,4-ethylenedioxyselenophene)s. Efficient visible to near-infrared absorption, photon to heat, and heat to electric conversion are realized in one polymer film.

All-optical switching—controlling light with light—has the potential to meet the ever-increasing demand for data transmission bandwidth. The development of organic π-conjugated molecular materials with the requisite properties for all-optical switching applications has long proven to be a significant challenge. However, recent advances demonstrate that polymethine dyes have the potential to meet the necessary requirements. In this review, we explore the theoretical underpinnings that guide the design of π-conjugated materials for all-optical switching applications. We underline, from a computational chemistry standpoint, the relationships among chemical structure, electronic structure, and optical properties that make polymethines such promising materials.

Polymethine dyes have the potential to meet the stringent requirements for all-optical switching applications: that is, controlling light with light. Here, we review the theory behind the design of π-conjugated molecular materials for all-optical switching applications and examine the role of computational chemistry in exploring the optical properties of these systems

A photocleavable energy-transfer dyad was synthesized, characterized, and applied to single-molecule fluorescence microscopy. After photocleavage, a combination of independent two-color single-molecule tracking and analysis of single-molecule energy-transfer efficiencies allows the determination of the temporal evolution of the relative distances between both fragments from the nm to the μm scale. This gives access to a broad range of diffusion coefficients.