Fengting Lv

Multifunctional Cationic Poly(p‐phenylene vinylene) Polyelectrolytes for Selective Recognition, Imaging, and Killing of Bacteria Over Mammalian Cells

The rapidly increasing emergence of antibiotic resistance to pathogen bacteria is becoming a serious global public health problem. [ 1 , 2 ] Thus, in addition to the ongoing development of new antibiotics, a major research effort has been made to develop alternative antibacterial therapeutics that are not easily able to develop resistance, such as bacteriophages, [ 3 ] quaternary ammonium (QA) compounds, [ 4 , 5 ] and antimicrobial peptides. [ 6 , 7 ] In recent years, photodynamic therapy (PDT) as a primary treatment for cancer has found new application in the killing of bacteria and has been proposed as a therapy for localized pathogen infections. [ 8–10 ] Reactive oxygen species (ROS) generated under light irradiation in the presence of photosensitizer and oxygen [ 11 ] are mainly responsible for the killing of bacteria. The multiantibiotic resistant bacteria can be easily killed by PDT and the bacteria do not readily develop resistance to PDT. [ 12 , 13 ] Despite much work in the application of PDT for localized pathogen infections, demonstrations of the selective killing of bacteria over host mammalian cells are few. [ 14 , 15 ]

Preparation and Biofunctionalization of Multicolor Conjugated Polymer Nanoparticles for Imaging and Detection of Tumor Cells

Dr. L. Feng School of Chemistry and Chemical Engineering Shanxi University Taiyuan , 030006 , P. R. China Dr. L. Feng, Dr. L. Liu, Dr. F. Lv, Prof. S. Wang Beijing National Laboratory for Molecular Sciences Key Laboratory of Organic Solids Institute of Chemistry Chinese Academy of Sciences Beijing 100190 , P. R. China E-mail: wangshu@iccas.ac.cn Prof. G. C. Bazan Departments of Chemistry & Biochemistry and Materials, Center for Polymers and Organic Solids University of California Santa Barbara , CA 93106–9510 , USA E-mail: bazan@chem.ucsb.edu

Chemical molecule-induced light-activated system for anticancer and antifungal activities.

Except for chemotherapy, surgery, and radiotherapy, photodynamic therapy (PDT) as new therapy modality is already in wide clinic use for the treatment of various diseases. The major bottleneck of this technique is the requirement of outer light source, which always limits effective application of PDT to the lesions in deeper tissue. Here, we first report a new modality for treating cancer and microbial infections, which is activated by chemical molecules instead of outer light irradiation. In this system, in situ bioluminescence of luminol can be absorbed by a cationic oligo(p-phenylene vinylene) (OPV) that acts as the photosensitizer through bioluminescence resonance energy transfer (BRET) process. The excited OPV sensitizes oxygen molecule in the surroundings to produce reactive oxygen species (ROS) that kill the adjacent cancer cells in vitro and in vivo, and pathogenic microbes. By avoiding the use of light irradiation, this work opens a new therapy modality to tumor and pathogen infections.

Cationic Conjugated Polymers for Discrimination of Microbial Pathogens

H. Yuan, Dr. L. Liu, Dr. F. Lv, Prof. S. Wang Key Laboratory of Organic Solids Interface and Chemical Thermodynamics Institute of Chemistry Chinese Academy of Sciences Beijing 100190 , P. R. China Fax: (+86) 10-6263-6680 E-mail: liulibing@iccas.ac.cn; wangshu@iccas.ac.cn Z. Liu, Prof. Y. Wang Key Laboratory of Colloid Interface and Chemical Thermodynamics Institute of Chemistry Chinese Academy of Sciences Beijing 100190 , P. R. China E-mail: yilinwang@iccas.ac.cn DOI: 10.1002/adma.201400636 conjugated polymers have been used for detection and identifi cation of various bacteria mainly based on the analyte-induced displacement of fl uorophore with the aid of linear discriminant analysis (LDA). [ 26–29 ] The sensing elements in these systems must include one charged conjugated polymer (donors) and several (three to fi ve) gold nanoparticles or dye-labeled DNAs (acceptors). It will be ideal to develop new methods only based on single conjugated polymer to discriminate multiple pathogens rapidly and simply. In this work, we prepared a new cationic poly(phenylene vinylene) derivative (PPV-NMe 3 + , see Scheme 1 for its structure and synthesis). Through the specifi c interactions of PPV-NMe 3 + to microbial cell envelopes with different components, it is demonstrated that single PPV-NMe 3 +

Conjugated-polymer-based energy-transfer systems for antimicrobial and anticancer applications.

Conjugated polymers (CPs) attract a lot of attention in sensing, imaging, and biomedical applications because of recent achievements that are highlighted in this Research News article. A brief review of recent progress in the application of CP-based energy-transfer systems in antimicrobial and anticancer treatments is provided. The transfer of excitation energy from CPs to photosensitizers leads to the generation of reactive oxygen species (ROS) that are able to efficiently kill pathogenic microorganisms and cancer cells in the surroundings. Both fluorescence resonance energy transfer (FRET) and bioluminescence energy transfer (BRET) modes are discussed.

A Convenient Preparation of Multi‐Spectral Microparticles by Bacteria‐Mediated Assemblies of Conjugated Polymer Nanoparticles for Cell Imaging and Barcoding

A novel technique was developed for preparing encoded multicolour microparticles based on the self-assembly of bacteria and conjugated polymer nanoparticles (CPNs) by a very simple and time-saving manner. These bacteria-CPNs microparticles show multicolor emissions by tuning FRET efficiencies among CPNs under single excitation wavelength and can be successfully applied for cell imaging and optical barcoding.

Detection and differential diagnosis of colon cancer by a cumulative analysis of promoter methylation

Alterations in the methylation of promoters of cancer-related genes are promising biomarkers for the early detection of disease. Compared with single methylation alteration, assessing combined methylation alterations can provide higher association with specific cancer. Here we use cationic conjugated polymer-based fluorescence resonance energy transfer to quantitatively analyse DNA methylation levels of seven colon cancer-related genes in a Chinese population. Through a stepwise discriminant analysis and cumulative detection of methylation alterations, we acquire high accuracy and sensitivity for colon cancer detection (86.3 and 86.7%) and for differential diagnosis (97.5 and 94%). Moreover, we identify a correlation between the CpG island methylator phenotype and clinically important parameters in patients with colon cancer. The cumulative analysis of promoter methylation alterations by the cationic conjugated polymer-based fluorescence resonance energy transfer may be useful for the screening and differential diagnosis of patients with colon cancer, and for performing clinical correlation analyses.

A Highly Emissive Conjugated Polyelectrolyte Vector for Gene Delivery and Transfection

An intrinsically fluorescent cationic polyfluorene (CCP) has been designed, synthesized, characterized, and examined as a plasmid DNA (pDNA) delivery vector. This material facilitates nucleic acid binding, encapsulation and efficient cellular uptake. CCP can effectively protect pDNA against nuclease degradation, which is necessary for gene carriers. Green fluorescent protein (GFP) expression experiments reveal that CCP can achieve efficient delivery and transfection of pDNA encoding GFP gene with 92% efficiency, which surpasses that of commercial transfection agents, lipofectamine 2000 (Lipo) and polyethylenimine (PEI). CCP is also highly fluorescent, with 43% quantum yield in water, and exhibits excellent photostability, which allows for real-time tracking the location of gene delivery and transfection. These features and capabilities represent a major step toward designing and applying conjugated polymers that function in both imaging and therapeutic applications.

An Optical Nanoruler Based on a Conjugated Polymer−Silver Nanoprism Pair for Label‐Free Protein Detection

An optical nanoruler system based on a conjugated polyelectrolyte-silver nanoprism pair is developed for label-free protein detection by taking advantage of the metal-enhanced fluorescence effect of silver nanostructures. Antibody-antigen interactions induce a change in the metal-fluorophore distance, followed by the response of a fluorescent signal of the conjugated polyelectrolyte. The system is used to detect target antigens sensitively and selectively.

Conjugated Polymer‐Coated Bacteria for Multimodal Intracellular and Extracellular Anticancer Activity

IO N The development of controlled drug loading, delivery and release systems for cancer therapy seems increasingly important due to the worldwide growing morbidity and mortality caused by neoplastic diseases year by year. [ 1 ] Cancer patients treated by conventional dosage of drug strategies such as chemotherapy always suffer from low effi cacy and severe side effects. [ 2 ] Therefore, it is necessary to explore more advanced systems for better treatment of cancer with high specifi city, excellent temporal and spatial controllability and ultimately improved effi cacy. To achieve this goal, researchers have made great efforts in the design and development of various advanced strategies to transport and liberate the loaded antitumor drugs. [ 3–11 ] The currently utilized carriers for controlled drug loading, delivery and release primarily include polymeric systems, [ 3–7 ] dendrimer-based micelles, [ 8 ] silica-based porous materials, [ 9 , 10 ] and liposomes. [ 11 ]