Surface and interfacial engineering of heterogeneous metal catalysts is effective and critical for optimizing selective hydrogenation for fine chemicals. By using thiol-treated ultrathin Pd nanosheets as a model catalyst, we demonstrate the development of stable, efficient, and selective Pd catalysts for semihydrogenation of internal alkynes. In the hydrogenation of 1-phenyl-1-propyne, the thiol-treated Pd nanosheets exhibited excellent catalytic selectivity (>97%) toward the semihydrogenation product (1-phenyl-1-propene). The catalyst was highly stable and showed no obvious decay in either activity or selectivity for over ten cycles. Systematic studies demonstrated that a unique Pd-sulfide/ thiolate interface created by the thiol treatment was crucial to the semihydrogenation. The high catalytic selectivity and activity benefited from the combined steric and electronic effects that inhibited the deeper hydrogenation of C=C bonds. More importantly, this thiol treatment strategy is applicable to creating highly active and selective practical catalysts from commercial Pd/C catalysts for semihydrogenation of internal alkynes.
Apart from the wide applications in the field of electronic and optoelectronic devices, conjugated molecules have been established as useful functional materials for biological applications. By introducing hydrophilic side chains to conjugated backbones, water-soluble conjugated polymers or oligomers (CPs or COs) inherit the attractive optical and electronic properties from conjugated molecules, while their water solubility ensures interaction with biological substrates such as biomacromolecules, microorganisms, and living cells for further biological applications. Benefiting from high brightness, large extinction coefficients, excellent photostability, low cytotoxicity, stability in bodily fluids, and versatile structural modifications, water-soluble conjugated polymers and oligomers have offered powerful alternatives in a variety of biological applications including biological and chemical sensors, fluorescence imaging, disease diagnostics, and therapy. This Account will focus on our recent advances in design, synthesis, and interdisciplinary biological applications of a series of new water-soluble CP and CO materials, starting with a brief introduction to water-soluble CPs and COs and various methods and strategies developed for the preparation of advanced water-soluble CPs and COs. Since their properties can be tuned by rational design and synthesis at the level of the conjugated repeat unit and versatile pendant groups, CPs and COs provide a diverse toolbox for satisfying interdisciplinary biological applications. The application of water-soluble CPs and COs in the past five years can be broadly categorized into four areas. Specifically, integrating the unique optoelectronic properties of water-soluble CPs and COs with self-assembly and supramolecular strategies, efficacy regulation of antibiotic and anticancer drugs has been achieved, meanwhile drug resistance could be overcome and drug resistant “superbacteria” can be inhibited. For applications regulating cellular functions and biological processes, we introduce CPs and COs with the ability to regulate intracellular oxidative stress, cell–cell communication, cellular proliferation, cell membrane permeability, and quorum sensing of bacteria cells. By covalent linkage of reactive groups upon CPs and COs, these molecules are endowed with abilities like disassembly of amyloid polypeptides, biased distribution in cells, selective imaging of organelles, and distinguished interactions with biomolecules. For photothermal therapy (PTT) applications, photothermal-responsive conjugated polymer materials have been utilized for remote control of gene expression in living cells and in vivo photothermal therapy of cancer. Beyond these applications, we have achieved new interdisciplinary applications of water-soluble CP and CO materials for biological optoelectronic devices including photosynthesis, photocatalysis, and bioenergy. Specific features or properties of water-soluble CPs and COs are leveraged to bring opportunities for each of these applications. These studies...
Carriers that can afford tunable physical and structural changes are envisioned to address critical issues in controlled drug delivery applications. Herein, photo-responsive conjugated polymer nanoparticles (CPNs) functionalized with donor-acceptor Stenhouse adduct (DASA) and folic acid units for controlled drug delivery and imaging are reported. Upon visible-light (λ=550 nm) irradiation, CPNs simultaneously undergo structure, color, and polarity changes that release encapsulated drugs into the cells. The backbone of CPNs favors FRET to DASA units boosting their fluorescence. Notably, drug-loaded CPNs exhibit excellent biocompatibility in the dark, indicating perfect control of the light trigger over drug release. Delivery of both hydrophilic and hydrophobic drugs with good loading efficiency was demonstrated. This strategy enables remotely controlled drug delivery with visible-light irradiation, which sets an example for designing delivery vehicles for non-invasive therapeutics.
Power generation and charge storage devices are commonly uncoupled when it comes to the design of materials relevant for their fabrication. Here, it is demonstrated that the biotic–abiotic composite comprising the self‐doped conjugated polyelectrolyte CPE‐K and electrogenic bacteria Shewanella oneidensis MR‐1 can reversibly switch its function between electrical current generation in chronoamperometry mode (≈150 mA m−2) and electrochemical energy storage as a pseudocapacitor with a specific capacitance of up to 80 F g−1. Interconversion of desirable properties for the different functions is achieved by the simple addition and removal of Mg2+ in the bulk electrolyte. Potentiostatic, galvanostatic, and electrochemical impedance spectroscopy characterization, accompanied by imaging and cell viability tests, indicate that the modulation of properties is a result of reversible changes in CPE‐K macrostructures and in the number of living bacteria within the composite. The results show the possibility to realize an “on‐demand” switch between current generation and charge storage by one integrated “living” material.
Amine-grafted mesoporous silica materials with short channels and large pore diameters have been prepared and used to adsorb CO2 efficiently.
Protein misfolding and aberrant aggregations are associated with multiple prevalent and intractable diseases. Inhibition of amyloid assembly is apromising strategy for the treatment of amyloidosis.R eported here is the design and synthesis of areactive conjugated polymer,apoly(p-phenylene vinylene) derivative,f unctionalizedw ith p-nitrophenyl esters (PPV-NP) and it inhibits the assembly of amyloid proteins, degrades preformed fibrils,a nd reduces the cytotoxicity of amyloid aggregations in living cells.PPV-NP is attached to the proteins through hydrophobic interactions and irreversible covalent linkage.P PV-NP also exhibited the capacity to eliminate Ab plaques in brain slices in ex vivo assays.T his work represents an innovative attempt to inhibit protein pathogenic aggregates,and may offer insights into the development of therapeutic strategies for amyloidosis.Proteins are one of the most important basic bio-macromolecules in organisms.T he aberrant assembly of proteins into insoluble amyloid aggregates would disrupt their biological functions and result in the generation of toxic intermediates and amyloidosis,w hich are relevant to ar ange of intractable human disorders such as Alzheimersd isease, Parkinsonsd isease,d ialysis-related amyloidosis,a nd type-2 diabetes. [1][2][3][4][5][6][7] On this account, numerous approaches to inhibit amyloid assembly have emerged, ranging from synthetic and natural small-molecule compounds, [4,8,9] peptides, [10,11] antibodies, [12] and nanoparticles [13,14] to artificial chaperones, [15] which make certain achievements to the inhibition of pathogenic aggregates.H owever,t od ate,t he pharmacological treatments for these diseases are still unsatisfactory. [16] Rational chemical designs to effectively inhibit and disrupt the amyloid assembly are still of great significance.In fact, most previous inhibitors functioned through noncovalent interactions,s uch as hydrophobic interactions, p-p stacking,e lectrostatic interactions,a nd hydrogen bonding. These interactions are intrinsically weak and susceptible to the surrounding environment. [17] Thef luctuation of either pH or temperature may induce the disassembly of inhibitor/ protein complexes,and would make the inhibitors invalid. In contrast, covalent interactions are more chemically stable and not susceptible to the fluctuation of surrounding environment. Reactions between inhibitors and proteins are usually irreversible,and inhibitors could remain attached to proteins for long time.T hus,d eveloping new inhibiting materials for amyloid assembly with acovalent-linking strategy is expected to lead to prolonged duration of inhibition and improved efficiency.T he amphiphilic conjugated polymers are considered pioneering materials in the biomedical field owing to their unique photoelectrical properties. [18][19][20][21][22][23][24] Here,w e designed and synthesized ar eactive conjugated polymer, ap oly(p-phenylene vinylene) derivative,f unctionalized with p-nitrophenyl active esters (PPV-NP) to inhibit protein assembly and disru...
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