Luminescent Chemodosimeters for Bioimaging

Luminescent Chemodosimeters for Bioimagin

MMP2-Targeting and Redox-Responsive PEGylated Chlorin e6 Nanoparticles for Cancer Near-Infrared Imaging and Photodynamic Therapy

A unique matrix metalloproteinase 2-targeted photosensitizer delivery platform was developed in this study for tumor-targeting imaging and photodynamic therapy. The model photosensitizer therapeutic agent chlorin e6 (Ce6) was first covalently conjugated with matrix metalloproteinase 2-cleavable polypeptide and then modified with polyethylene glycol via a redox-responsive cleavable disulfide linker. The resultant matrix metalloproteinase 2-cleavable polypeptide modified PEGylated Ce6 (PEG-SS-Ce6-MMP2) nanoparticles, which formed via self-assembly, were observed to be monodisperse and significantly stable in aqueous solution. In addition, owing to their cellular redox-responsiveness at the cleavable disulfide linker, the PEG-SS-Ce6-MMP2 nanoparticles were able to release Ce6 rapidly. Despite displaying enhanced intracellular internalization, the synthesized PEG-SS-Ce6-MMP2 nanoparticles did not compromise their phototoxic effects toward A549 cancer cells when compared with free Ce6 and PEGylated Ce6 nanoparticles. <i>In vivo</i> experiments further revealed that, in contrast with the free Ce6 or with the PEGylated Ce6 nanoparticles, the PEG-SS-Ce6-MMP2 nanoparticles showed a remarkable increase in tumor-targeting ability and a significantly improved photodynamic therapeutic efficiency in A549 tumor-bearing mice. These results suggest that the PEG-SS-Ce6-MMP2 nanoparticles hold great potential for tumor-targeting imaging and photodynamic therapy

Additional file 4: Figure S2. of A genome-wide expression profile analysis reveals active genes and pathways coping with phosphate starvation in soybean

Identification of differently up-regulated genes in roots between different soybean accessions. (DOC 26 kb

Additional file 1: Figure S1. of A genome-wide expression profile analysis reveals active genes and pathways coping with phosphate starvation in soybean

Roots morphological of soybean accession CD and YH under low-P condition (0.005 mmol/L P) (A) Root morphological before low-P treatments (B) Root morphological after 10 days of low-P treatments. (DOC 190 kb

Additional file 2: Table S1. of A genome-wide expression profile analysis reveals active genes and pathways coping with phosphate starvation in soybean

KEGG and Go enrichment analysis of differently expressed genes. (a) 317 DEGs between different P treatments (b) 195 DEGs between different materials (c) 253 DEGs between different tissues (d) 85 overlapping genes between the 195 marked DEGs between CD and YH and 317 DEGs in roots and leaves (e) 68 overlapping genes between the 253 marked DEGs between roots and leaves and 317 DEGs in roots and leaves (f) 42 common DEGs. (XLS 86 kb

Additional file 5: Table S3. of A genome-wide expression profile analysis reveals active genes and pathways coping with phosphate starvation in soybean

10 genes showing opposite expression patterns in roots between different soybean accessions. (DOC 42 kb

Additional file 3: Table S2. of A genome-wide expression profile analysis reveals active genes and pathways coping with phosphate starvation in soybean

The list of DEGs between different P treatments in the roots and leaves of CD and YH. (XLS 55 kb

Nonleaching Bacteria-Responsive Antibacterial Surface Based on a Unique Hierarchical Architecture

Bacteria-responsive surfaces popularly exert their smart antibacterial activities by bacteria-triggered delivery of antibacterial agents; however, the antibacterial agents should be additionally reloaded for the renewal of these surfaces. Herein, a reversible, nonleaching bacteria-responsive antibacterial surface is prepared by taking advantage of a hierarchical polymer brush architecture. In this hierarchical surface, a pH-responsive poly­(methacrylic acid) (PMAA) outer layer serves as an actuator modulating the surface behavior on demand, while antimicrobial peptides (AMP) are covalently immobilized on the inner layer. The PMAA hydration layer renders the hierarchical surface resistant to initial bacterial attachment and biocompatible under physiological conditions. When bacteria colonize the surface, the bacteria-triggered acidification allows the outermost PMAA chains to collapse, therefore exposing the underlying bactericidal AMP to on-demand kill bacteria. In addition, the dead bacteria can be released once the PMAA chains resume their hydrophilicity because of the environmental pH increase. The functionality of the nonleaching surface is reversible without additional reloading of the antibacterial agents. This approach provides a new methodology for the development of smart surfaces in a variety of practical biomedical applications

Hierarchical Polymer Brushes with Dominant Antibacterial Mechanisms Switching from Bactericidal to Bacteria Repellent

Although polycationic surfaces have high antimicrobial efficacies, they suffer from high toxicity to mammalian cells and severe surface accumulation of dead bacteria. For the first time, we propose a surface-initiated photoiniferter-mediated polymerization (SI-PIMP) strategy of constructing a “cleaning” zwitterionic outer layer on a polycationic bactericidal background layer to physically hinder the availability of polycationic moieties for mammalian cells in aqueous service. In dry conditions, the polycationic layer exerts the contact-active bactericidal property toward the adherent bacteria, as the zwitterionic layer collapses. In aqueous environment, the zwitterionic layer forms a hydration layer to significantly inhibit the attachment of planktonic bacteria and the accumulation of dead bacteria, while the polycationic layer kills bacteria occasionally deposited on the surface, thus preserving the antibacterial capability for a long period. More importantly, the zwitterionic hydrated layer protects the mammalian cells from toxicity induced by the bactericidal background layer, and therefore hierarchical antibacterial surfaces present much better biocompatibility than that of the naked cationic references. The dominant antibacterial mechanism of the hierarchical surfaces can switch from the bactericidal efficacy in dry storage to the bacteria repellent capability in aqueous service, showing great advantages in the infection-resistant applications

Investigation of the Viability of Cells upon Co-Exposure to Gold and Iron Oxide Nanoparticles

Cell lines were exposed either to mixtures of gold and iron oxide nanoparticles, or to a hybrid nanoparticle with gold and iron oxide domain. In the case of simultaneous exposure to gold and iron oxide nanoparticles, enhanced toxicity as compared to the exposure to only one type of nanoparticles was observed. An indication was found that, at equivalent concentrations, the hybrid nanoparticles may slightly reduce cell viability more strongly than mixtures of both nanoparticle types. The results suggest that composite nanomaterials, in which different materials are present in particle form, need to be analyzed carefully, as not only the concentration of the respective materials but also their arrangement may influence their toxicity