Denitration of Nitroarenes Under Ambient Physiological Conditions Catalyzed by Graphdiyne-Supported Palladium

The direct cleavage of C–NO_(2)bonds for reductive denitration of nitroarenes remains a challenging transformation in synthetic organic chemistry.Herein,we report a biocompatible palladium-deposited graphdiyne nanocatalyst(Pd@GDY/DSPE-PEG)that can catalyze reductive denitration of nitroarenes under ambient physiological conditions.Mechanistic studies support this transformation via the oxidative addition of nitroarenes with Pd(0)and subsequent ligand exchange to form arylpalladium hydride.This one-step reductive denitration via Pd@GDY/DSPE-PEG successfully facilitates the repair of the nitrated proteins arising from endogenic ONOO−and restores their physiological function,including blocking the apoptosis pathway in living cells.Moreover,Pd@GDY/DSPE-PEG was further successfully applied for catalytic denitration to reduce the level of 3-nitrotyrosine residues of proteins located in the mouse brain hippocampus in vivo.This study provides an ideal strategy for designing highly active enzymatic mimicking synthetic catalysts for the regulation of the nitrated protein level and the detoxification of nitrative damage of living cells and tissues.

Controllable assembly of nitrogen-doped mesoporous carbon with different pore structures onto CNTs for excellent lithium storage

Mesoporous carbon nanomaterials have shown a great application potential in energy storage and conversion fields due to their outstanding conductivity,tunable pore structure,and good chemical stability.Nevertheless,how to accurately control the pore structure,especially directly assembling the mesoporous carbon onto different substrates remains a big challenge.Herein,we have successfully assembled two kinds of highly nitrogen-doped mesoporous carbon onto carbon nanotubes(NMC/CNTs)based on a facile cooperative assembly process assisted by triblock PEO_(20)PPO_(70)PEO_(20)(P123)and PEO_(106)PPO_(70)PEO_(106)(F127)copolymers.The experimental results indicate that the P_(123)/F_(127)mass ratio has a profound effect on the pore structure,leading to the formation of NMC/CNTs composites with spherical pore structure(S-NMC/CNTs)and cylindrical pore structure(CNMC/CNTs).In virtue of fast electron/ion transfer kinetics,the as-prepared S-NMC/CNTs anode demonstrates an excellent electrochemical performance for lithium-ion batteries,and it delivers a high reversible capacity of 588.1 mAh∙g^(−1)at the current of 0.1 A∙g^(−1)after 100 cycles,along with a superior cycling stability.Specifically noted,the controlled assembly route developed in our work can also be applied to other support materials with different structures and compositions.

Polymer Materials Synthesized through Cell-Mediated Polymerization Strategies for Regulation of Biological Functions

CONSPECTUS:As essential components of living organisms,biomacromolecules construct cell scaffolds and regulate cell activities and biological functions through chemical transformations in biological systems.Inspired by the functional evolution in the formation of natural structures,in situ polymerization methods have been developed to create functional synthetic macromolecules inside or on the surface of living cells.Given the diversity of cell species and the complexity of biological pathways,selected strategies can be employed to control the synthesis of functional polymers that utilize the dynamic cellular microenvironment.In this Account,we summarize recent work in the field of designing cell-mediated in situ polymerization methods,with which we demonstrate their application prospects including tumor cell labeling and treatment,microbial photosynthetic efficiency regulation,and hydrogel generation.The purpose of these efforts is to design polymerization reactions in response to endogenous or exogenous stimuli and to describe the underlying response mechanisms.By reasonable design of molecular structures,in situ synthesized polymers in the cell microenvironment implement regulation of biological functions.For example,using specific redox activity combined with light irradiation,bacteria can mediate the generation of functional polymers as the encapsulating matrix or with antibacterial effects.Conjugated polymers synthesized on the microalgae surface expanded the spectral absorption and improved photosynthetic efficiency.Meanwhile,characteristics of the cellular microenvironment could initiate various polymerization reactions inside living cells,including oxidative thiol cross-linking,condensation polymerization,and free radical polymerization.These reactions can be selectively conducted with reactive species generated in tumor cells,and the resulting polymers showed prolonged retention inside cells for modulating cell behaviors.Further development of cell-mediated polymerization strategies would provide an innovative platform for research and applications of multifunctional biomaterials and engineered biohybrid systems.

Synthesis of easily-processable collagen bio-inks using ionic liquid for 3D bioprinted liver tissue models with branched vascular networks

Bioprinting has been a flouring way to fabricate complex tissue and organ mimics via precisely depositing printable cell-laden biomaterials.However,there is a limited number of biomaterials that fulfill the mechanical property of printing while meeting the responsive environment desired for the cells.Despite excellent cell compatibility and bioactivity,collagen suffers from difficulties in processing and printability which inhibited its utilization in three-dimensional(3D)bioprinting.Herein,we address this limitation by using ionic liquid as the solvent in the modification process,enabling collagens modified with quantified norbornene for chemical crosslink and extrusion-based 3D printing.With improved solubility and rheological properties,norbornene-functionalized collagen(Col-Nor)exhibited better shape fidelity in extrusion-based 3D printing compared with the one before modification.Photo-crosslinked Col-Nor hydrogel provided structural support and promoted the adhesion,proliferation,and differentiation of various types of cells,which afforded a centimeter-scale liver tissue model.This highly generalizable methodology expands printable,versatile,and tunable hydrogels developed from the natural extracellular matrix,allowing the biofabrication of 3D liver tissue model with branched vascular networks.

Unexpected Photocatalytic Degeneration of NAD^(+) for Inducing Apoptosis of Hypoxia Cancer Cells

Developing customized chemical reactions that could regulate a specific biological process on demand is regarded as an advanced and promising strategy for treating diseases.However,conventional chemical reactions become challenging in complex physiological environments,which demand mild reaction conditions,high efficiency,good biocompatibility,and strong controllability.Moreover,the effects of the achieved reactions on the real biological system are usually further lessened.Herein,we describe an advanced photocatalytic reaction that irreversibly converted nicotinamide adenine dinucleotide(NAD+)to nicotinamide and adenosine diphosphate(ADP)-ribose by the cationic conjugated poly(fluorene-co-phenylene)(PFP).This reaction was introduced to tumor cells and triggered cell apoptosis.Under white-light illumination,the photocatalytic reaction decreased the NAD+ratio in tumor cells,disrupted the mitochondrial membrane potential,inhibited the synthesis of adenosine triphosphate(ATP),and effectively induced apoptosis.We propose a mechanism of the reaction where PFP is photoexcited to PFP*,and the obtained photoelectrons are transferred from PFP*to NAD+to produce nicotinamide and another unstable intermediate,ADP-ribosyl radical.ADP-ribosyl radical quickly reacts with triethanolamine to form ADP-ribose.This intracellular utilization of a specific photocatalytic reaction could offer a new approach to affect biological function for efficient cancer treatment.

共轭聚合物生物电子体系研究进展

共轭聚合物类的有机共轭分子由于其特殊的电子离域效应,具有优异的光电性能.另外该类材料骨架结构丰富、能带可调、易于修饰与制备,使得这类材料除了在发光二极管、场效应晶体管和光伏电池等方面有广泛的研究和应用之外,在生物成像、生物传感、疾病诊断和治疗中也发挥了重要作用.本文综述了近年来基于水溶性共轭聚合物的生物电子体系构建和应用,主要介绍了水溶性共轭聚合物在光合作用、生物燃料电池、生物光伏、生物电子催化等方面的最新研究进展.

Oligo(p-phenylenevinylene)-rhodium complex as intracellular catalyst for enhancing biosynthesis of polyhydroxybutyrate biomaterials

Microbial synthesis utilizes sustainable resources to produce valuable chemicals,as a potential alternative to petroleum-based chemical industry.Although metabolic engineering is an efficient method to enhance the biosynthesis efficacy of microorganisms,it requires complicated biological procedures.Herein,we report a facile intracellular catalysis system for augmenting the production of bio-based material in microorganism.Covalent linking of oligo(p-phenylenevinylene)(OPV)and cyclopentadienyl rhodium(Ⅲ)bipyridine offers intracellular metal catalyst(OPV-Rh).The OPV-Rh complex displayed certain resistance to toxic biomolecules,which guaranteed its catalytic activity in complicated biological systems.With uptake by Gramnegative bacterium Ralstonia eutropha H16(R.eutropha H16),the OPV-Rh complex promotes the transformation of intracellular NADP+to NADPH,which further enhances the biosynthesis of polyhydroxybutyrate(PHB)by this microorganism.This work demonstrates that synthetic metal catalyst can be employed for regulating microbial biosynthesis intracellularly.

Solar-Driven Producing of Value-Added Chemicals with Organic Semiconductor-Bacteria Biohybrid System

Photosynthetic biohybrid systems exhibit promising performance in biosynthesis;however,these systems can only produce a single metabolite and cannot further transform carbon sources into highly valuable chemical production.Herein,a photosynthetic biohybrid system integrating biological and chemical cascade synthesis was developed for solar-driven conversion of glucose to value-added chemicals.A new ternary cooperative biohybrid system,namely bacterial factory,was constructed by self-assembling of enzyme-modified light-harvesting donor-acceptor conjugated polymer nanoparticles(D-A CPNs)and genetically engineered Escherichia coli(E.coli).The D-A CPNs coating on E.coli could effectively generate electrons under light irradiation,which were transferred into E.coli to promote the 37%increment of threonine production by increasing the ratio of nicotinamide adenine dinucleotide phosphate(NADPH).Subsequently,the metabolized threonine was catalyzed by threonine deaminase covalently linking with D-A CPNs to obtain 2-oxobutyrate,which is an important precursor of drugs and chemicals.The 2-oxobutyrate yield under light irradiation is increased by 58%in comparison to that in dark.This work provides a new organic semiconductor-microorganism photosynthetic biohybrid system for biological and chemical cascade synthesis of highly valuable chemicals by taking advantage of renewable carbon sources and solar energy.

Design of antibacterial peptide-like conjugated molecule with broad spectrum antimicrobial ability

Increasing multidrug-resistant(MDR) superbugs emerge worldwide causing a public health crisis. Consequently, it is urgent to find new antibiotics with efficient broad-spectrum antimicrobial activity. By virtue of versatility in molecular design, a new peptide-like cell membrane-broken molecule, oligo-(7,7′-bifluoren-benzo[c][1,2,5]thiadiazole)(OFBT) possessing a conjugated backbone and eight pendant guanidyl moieties was designed and synthesized. OFBT exhibits favorable broad-spectrum of antimicrobial activity to pathogens including Gram-negative and Gram-positive bacteria, and fungi with the minimum inhibitory concentration(MIC)below 3.0 μM. Moreover, OFBT exhibits high selectivity for pathogens over human cells to make it a promising broad spectrum antimicrobial agent.

Cationic conjugated polymers for detection and inactivation of pathogens

Conjugated polymers(CPs) are referred to a kind of fluorescent polymer materials with delocalized π-conjugated backbones.For the last decades, cationic CPs(CCPs) have been widely used in biosensor, imaging and biomedical fields due to their good photophysical properties and solubility in water medium resulting from side chain modification with ionized moieties. In this mini-review, we mainly introduced the applications of CCPs in detection and inactivation of pathogen with typical examples, and also briefly discussed the relevant mechanisms. We hold the expectation that this mini-review can offer researchers a general reference and inspire them to construct new systems with high performances of pathogen detection and antimicrobial activity.

Living Bacteria-Mediated Aerobic Photoinduced Radical Polymerization for in Situ Bacterial Encapsulation and Differentiation

Conventional polymerizations mediated by living cells typically require synthetic transition-metal complexes or photoredox catalysts.Herein,we report an alternative photoinduced polymerization strategy for preparing functional polymer hydrogels through bacteria-initiated radical polymerization of acrylamides in ordinary culture media.Upon light irradiation under ambient conditions,polyacrylamides were obtained with molecular weights of over 150 kDa using various bacteria.

In Situ-Induced Multivalent Anticancer Drug Clusters in Cancer Cells for Enhancing Drug Efficacy

Increasing intracellular drug concentration is an effec-tive way for cancer chemotherapeutics to enhance efficacy and combat drug resistance.In this work,a series of anticancer drug conjugates were prepared by linking thiol-modified oligo(p-phenylene viny-lene)with paclitaxel,vincristine,teniposide,tamoxi-fen,doxorubicin,or podophyllotoxin(OPV-S-Drugs)through a Michael addition reaction.

Conjugated polymer nanoparticles as fluorescence switch for selective cell imaging

Fluorescence switch plays a vital role in bioelectronics and bioimaging.Herein,we presented a new kind of facile electrostatic complex nanoparticles(ECNs)for fluorescence switching in cells and marking of individual cell.The ECNs were prepared by mixing positively charged poly(6-(2-(thiophen-3-yl)ethoxy)hexyl trimethylammonium bromide)(PT)and negatively charged diarylethene sodium salt(DAECOONa).DAE-COONa is a photoswitchable molecule which can be transformed between the ring-closed fo rm and ring-open form under the irradiation of UV or visible light.The closed-form of DAE-COONa can efficie ntly quench the fluorescence of PT through intermolecular energy transfer,while the open form of DAE-COONa does not influence the emission of PT.Thus,the fluorescence of ECNs can be modulated by light irradiation,and the ECNs with good fluorescence switching performance have been employed for fluorescence imaging and individual cell lighting up process successfully.We demonstrate that the electrostatic complex strategy provides a facile method to construct fluorescence switch fo r selective cell marking and imaging applications.

Synthesis of amphiphilic poly(fluorene) derivatives for selective imaging of Staphylococcus aureus

Three amphiphilic poly(fluorene-co-phenylene) derivatives with different side chains(PFP-1, PFP-2, PFP-3) were designed and synthesized for exploring their detection and imaging of pathogens. Upon incubation with six kinds of different pathogens, it was found the three polymers could selectively interact with Staphylococcus aureus(S. aureus). Their selective imaging towards S. aureus were thus realized. The selective imaging towards S. aureus was also confirmed even under the blend of microbes. PFP-3 shows stronger fluorescence imaging signal than PFP-1 and PFP-2. Zeta potential and isothermal titration microcalorimetry(ITC) tests demonstrated that both electrostatic interactions and hydrophobic interactions played important roles in the binding between PFPs and pathogens. Thus, amphiphilic PFP-3 exhibits great potential for specific imaging of S. aureus in a simple and rapid manner.

Selective biocompatibility and responsive imaging property of cationic conjugated polyelectrolyte to cancer cells

Optical imaging, as an important molecular imaging modality, has emerged many attractions in studying the biological or molecular events both in cell level and living subject because of its high resolution and sensitivity, noninvasive manner and low cost. Herein, we bring novel insights into a water-soluble conjugated polyelectlyte by deeply studying its properties in cells. Poly（9, 9-bis（6＇-N,N,N-trimethylammonium hexyl）fluorene phenylene）（PFP）, a good biosensing material, was studied in this paper. The biocompatibility of PFP was investigated in different cells, and cell cycle analysis was carried out to explore the reasons of different biocompatibility of PFP to cells. After irradiation, fluorescence enhancement of blue emission and turn-on of long-wavelength emission of PFP in HepG2 cells was observed, which was first reported as far as we know. The differentiated biocompatibility of PFP and its particular imaging properties in cancer cells can help to guide the application of conjugated polymers in cells and provide a new dimension in designing sensitive and responsive imaging materials.

天然来源的纳米类囊体应用于肿瘤的多模式治疗

多模式联合治疗已成为抗肿瘤的有效手段,但目前已报道的多模式肿瘤治疗试剂通常需要复杂的功能组分和繁琐的合成过程.因此,开发一种简单制备的天然来源多模式肿瘤治疗试剂仍然是一个挑战.本文从菠菜叶片中提取出了一种天然来源的、具有类酶性质的纳米类囊体用于肿瘤的多模式治疗.结果表明,纳米类囊体具有良好的光热转换和光敏化性质,可以有效杀伤4T1和MCF-7肿瘤细胞.同时,该材料还具有类过氧化物酶的性质,可以氧化分解过氧化氢产生羟基自由基从而诱导肿瘤细胞凋亡.因MCF-7肿瘤细胞内过量表达过氧化氢,该材料可实现对MCF-7肿瘤细胞的选择性杀伤.该纳米类囊体在细胞水平和活体小动物水平对肿瘤具有显著的治疗效果,且表现出良好的生物安全性.研究表明,该纳米类囊体具有光热转换、光敏化、类过氧化物酶的性质,是一类很有应用前景的多模式肿瘤治疗试剂.

Electrochemical Regulation of Antibacterial Activity Using Ferrocene-Containing Antibiotics

The widespread use of antibiotics causes the accumulation of a large amount of antibiotics in the environment.Excessively active antibiotics in the environment results in the emergence of bacterial resistance.Building smart antibiotics capable of reversible regulation between active and inactive states on demand is a promising approach to address this issue.Herein,a ferrocene-containing quaternary ammonium compound has been developed for electrochemical redox-controlled bacterial inhibition.The reversible switch of the reduced and oxidized ferrocene groups between hydrophobic and hydrophilic states triggers the assembly and disassembly of the micelles while modulating the interactions of antibiotic molecules with the bacteria membrane,providing a new way to regulate antibacterial activity.In addition,the alternate use of reduced and oxidized antibiotics exhibits a favorable effect in preventing bacterial resistance.Thus,an unconventional strategy is offered to prevent the build-up of active bactericide in the environment and decrease bacterial resistance.