Photothermal-Responsive Conjugated Polymer Nanoparticles for the Rapid and Effective Killing of Bacteria

The emergence of drug-resistant bacterial strains makes antimicrobial treatment a big challenge. Thus, more novel and effective antimicrobial agents and treatments are urgently desired. Herein, we developed a facile and rapid photothermal antimicrobial nanoplatform based on near-infrared (NIR)-active and photothermal-responsive conjugated polymer nanoparticles (CPNs) functionalized with cell-penetrating peptide (CPNs-Tat). With a positively charged Tat peptide, CPNs-Tat could enhance the interaction with bacteria cells with the formation of CPNs-Tat/bacteria aggregation. Under NIR irradiation, CPNs-Tat could convert the light into heat efficiently and produce local hyperthermia to kill bacteria within a few minutes. This photothermal-responsive strategy offers a rapid and effective modality for combating bacterial infections

Polarity Conversion of Conjugated Polymer for Lysosome Escaping

Polymers are mostly trapped in lysosomes when they enter cells and are then expelled, otherwise they were designed to be degradable to small molecules or to sabotage lysosomes. Therefore, they have reached the limit of the unique functionalities as a whole. Different from other escaping strategies, we introduced the polarity exchanging approach to rigid-backboned conjugated polymer for controlled penetrating through endosome or lysosome membranes. With the aid of pH-sensitive cleavage of water-soluble side chain, the rigid conjugated polymer turns highly hydrophobic after it is internalized into lysosomes and then accomplishes escaping. Thus, polarity exchange of CPs could become a new strategy for their application on chemotherapeutics

Sensitivity analysis of the exo-RPA assay.

<p>Different copy numbers of plasmid pMD19-T-TK DNA (10⁶ to 10⁰ copies) were amplified by either RPA reactions or real time PCR. As shown in this figure, the detection limit was 10² copies of DNA/reaction for both the exo-RPA assay (panel A) and real time PCR (panel B). The copy numbers used as template for curve 1–7 were 10⁶, 10⁵, 10⁴, 10³, 10², 10¹ and 10⁰, respectively. Shown in this figure is one representative plot out of 5 independent reactions for RPA and real time PCR, respectively.</p

Visual Detection of DNA Mutation Using Multicolor Fluorescent Coding

A visual colorimetric method for detecting multiplex DNA mutations has been developed using multicolor fluorescent coding based on multistep FRET of cationic conjugated polymers. Expensive instruments and technical expertise are not required in this method. Also our visual system provides a quantitative detection by simply analyzing RGB values of images. Genomic DNAs extracted from 60 FFPE colon tissues can be sensitively determined by utilizing our visual assay with a high-throughput manner. Thus, it proves to be sensitive, reliable, cost-effective, simple, and high-throughput for mutation detection

The co-efficient of variation from 5 independent reactions.

<p>The co-efficient of variation from 5 independent reactions.</p

pH-Responsive Peptide Supramolecular Hydrogels with Antibacterial Activity

Smart hydrogels have received increasing attention for many applications. Here, we synthesized a class of cationic peptide amphiphiles that can self-assemble into hydrogels by ring-opening polymerization (ROP) and post-modification strategy. The incorporation of cationic lysine residues suppresses the formation of fibril-like structure and further the gelation ability of the samples. Sodium alginate (SA) is used to enhance the rheology performance of the hydrogels. The hydrogels exhibit pH-dependent self-assembly and the gelation behavior that enables them to be ideal smart hydrogel systems for biomedical applications. Furthermore, the as-prepared hybrid peptide hydrogels show antibacterial activity

DNA Hydrogel by Multicomponent Assembly for Encapsulation and Killing of Cells

In this work, a new multifunctional assembled hydrogel was prepared by incorporating gadolinium ions (Gd³⁺) with salmon-sperm DNA and polythiophene derivative (PT-COOH) through chelation interactions. Efficient energy transfer from PT-COOH to Gd³⁺ ions takes place followed by sensitization of oxygen molecule to generate reactive oxygen species (ROS) under light irradiation. Cancer cells can be encapsulated into the hydrogel in situ as the formation of hydrogel followed by killing by the ROS. Integration of imaging modality with therapeutic function within a single assembled hydrogel is therefore anticipated to be a new and challenging design element for new hydrogel materials

Synthesis of a Novel Quinoline Skeleton Introduced Cationic Polyfluorene Derivative for Multimodal Antimicrobial Application

A new functional polyfluorene derivative containing quinoline skeleton and quarternary ammonium group (QAG) modified side chains (PFPQ) was synthesized and characterized. The multimodal antimicrobial effect toward Gram-negative E. coli was achieved by the dark toxicity resulting from the quinoline skeleton, QAG, and light toxicity resulting from reactive oxygen species (ROS) produced by the main backbone of PFPQ under white light. The mechanism of interaction between PFPQ and bacteria was also demonstrated. PFPQ bound to E. coli mainly through electrostatic interactions causing nearly 50% bacterial death in the absence of light irradiation, and the huge capability of PFPQ to generate ROS under white light opened another bactericidal mode. The killing efficiency was more than 99% upon relatively mild irradiation under white light (400–800 nm) with a light dose of 18 J·cm^–2. PFPQ with the incorporation of quinoline into the backbones will provide a new versatile strategy to achieve the multimodal antimicrobial effect to fight against resistant bacteria

Additional file 1: of Development of real-time recombinase polymerase amplification assay for rapid and sensitive detection of canine parvovirus 2

Detection of CPV-2 in clinical samples by real-time RPA, real-time PCR and SNAP. (DOCX 14 kb