Polymer encapsulated organic nanoparticles have recently attracted increasing attention in the biomedical field because of their unique optical properties, easy fabrication and outstanding performance as imaging and therapeutic agents. Of particular importance is the polymer encapsulated nanoparticles containing conjugated polymers (CP) or fluorogens with aggregation induced emission (AIE) characteristics as the core, which have shown significant advantages in terms of tunable brightness, superb photo- and physical stability, good biocompatibility, potential biodegradability and facile surface functionalization. In this review, we summarize the latest advances in the development of polymer encapsulated CP and AIE fluorogen nanoparticles, including preparation methods, material design and matrix selection, nanoparticle fabrication and surface functionalization for fluorescence and photoacoustic imaging. We also discuss their specific applications in cell labeling, targeted in vitro and in vivo imaging, blood vessel imaging, cell tracing, inflammation monitoring and molecular imaging. We specially focus on strategies to fine-tune the nanoparticle property (e.g. size and fluorescence quantum yield) through precise engineering of the organic cores and careful selection of polymer matrices. The review also highlights the merits and limitations of these nanoparticles as well as strategies used to overcome the limitations. The challenges and perspectives for the future development of polymer encapsulated organic nanoparticles are also discussed.

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Polymer-encapsulated organic nanoparticles for fluorescence and photoacoustic imaging

Nanomedicine therapeutic approaches to overcome cancer drug resistance.

Spatiotemporal control of singlet oxygen (1O2) release is a major challenge for photodynamic therapy (PDT) against cancer with high therapeutic efficacy and minimum side effects. Here a selenium-rubyrin (NMe2Se4N2)-loaded nanoparticle functionalized with folate (FA) was designed and synthesized as an acidic pH-activatable targeted photosensitizer. The nanoparticles could specifically recognize cancer cells via the FA-FA receptor binding and were selectively taken up by cancer cells via receptor-mediated endocytosis to enter lysosomes, in which NMe2Se4N2 was activated to produce 1O2. The pH-controllable release of 1O2 specially damaged the lysosomes and thus killed cancer cells in a lysosome-associated pathway. The introduction of selenium into the rubyrin core enhanced the 1O2 generation efficiency due to the heavy atom effect, and the substitution of dimethylaminophenyl moiety at meso-position led to the pH-controllable activation of NMe2Se4N2. Under near-infrared (NIR) irradiation, NMe2Se4N2 possessed h...

Cell-Specific and pH-Activatable Rubyrin-Loaded Nanoparticles for Highly Selective Near-Infrared Photodynamic Therapy against Cancer

Anti-PEG antibodies: Properties, formation, testing and role in adverse immune reactions to PEGylated nano-biopharmaceuticals

Liposomes are used as a delivery vehicle for drug molecules and imaging agents. The major impetus in their biomedical applications comes from the ability to prolong their circulation half-life after administration. Conventional liposomes are easily recognized by the mononuclear phagocyte system and are rapidly cleared from the blood stream. Modification of the liposomal surface with hydrophilic polymers delays the elimination process by endowing them with stealth properties. In recent times, the development of various materials for surface engineering of liposomes and other nanomaterials has made remarkable progress. Poly(ethylene glycol)-linked phospholipids (PEG-PLs) are the best representatives of such materials. Although PEG-PLs have served the formulation scientists amazingly well, closer scrutiny has uncovered a few shortcomings, especially pertaining to immunogenicity and pharmaceutical characteristics (drug loading, targeting, etc.) of PEG. On the other hand, researchers have also begun questioning the biological behavior of the phospholipid portion in PEG-PLs. Consequently, stealth lipopolymers consisting of non-phospholipids and PEG-alternatives are being developed. These novel lipopolymers offer the potential advantages of structural versatility, reduced complement activation, greater stability, flexible handling and storage procedures and low cost. In this article, we review the materials available as alternatives to PEG and PEG-lipopolymers for effective surface modification of liposomes.

https://www.mdpi.com/1999-4923/5/4/542/pdf

Surface engineering of liposomes for stealth behavior.

Poly(ethylene glycol)-distearoylphosphatidylethanolamine (PEG-DSPE) block copolymers are biocompatible and amphiphilic polymers that can be widely utilized in the preparation of liposomes, polymeric nanoparticles, polymer hybrid nanoparticles, solid lipid nanoparticles, lipid-polymer hybrid nanoparticles, and microemulsions. Particularly, the terminal groups of PEG can be activated and linked to various targeting ligands, which can prolong the circulation time, improve the drug bioavailability, reduce undesirable side effects, and especially target specific cells, tissues, and even the intracellular localization in organelles. This review herein aims to describe recent developments in drug carriers exploiting PEG-DSPE block copolymers and their derivatives, and the incorporation of different ligands to the end groups of PEG-DSPE to target delivery, focusing on their modification approaches, advantages, applications, and the probable associated drawbacks.

/pdf/application-of-poly-ethylene-glycol-2gptw4gs73.pdf

Application of poly(ethylene glycol)–distearoylphosphatidylethanolamine (PEG-DSPE) block copolymers and their derivatives as nanomaterials in drug delivery

Simple Summary We probed the effect of a probiotic complex on the immune response caused by Plesiomonas shigelloides infection in the southern catfish. Our study revealed the key genes for this inflammatory response, and the probiotic complex effectively inhibited the expression of key inflammatory factors caused by P. shigelloides, providing basic data for future artificial breeding of the southern catfish and the prevention and control of bacterial diseases caused by P. shigelloides. Abstract To explore whether a probiotic complex composed of Lactobacillus rhamnosus, Lactobacillus plantarum, and Lactobacillus casei can prevent or inhibit the inflammatory response caused by the invasion of Plesiomonas shigelloides in the southern catfish, we screened differentially expressed genes and enriched inflammation-related pathways among a control and three experimental groups and conducted analysis by transcriptome sequencing after a 21-day breeding experiment. Compared with those in the PS (Plesiomonas shigelloides) group, southern catfish in the L-PS (Lactobacillus-Plesiomonas shigelloides) group had no obvious haemorrhages or ulcerations. The results also showed that inflammation-related genes, such as mmp9, cxcr4, nfkbia, socs3, il-8, pigr, tlr5, and tnfr1, were significantly upregulated in the PS group compared with those in the L-PS groups. In addition, we verified six DEGs (mmp9, cxcr4, nfkbia, socs3, rbp2, and calr) and three proteins (CXCR4, NFKBIA, and CALR) by qRT-PCR and ELISA, respectively. Our results were consistent with the transcriptome data. Moreover, significantly downregulated genes (p < 0.05) were enriched in inflammation-related GO terms (lymphocyte chemotaxis and positive regulation of inflammatory response) and immune-related pathways (intestinal immune network for IgA production and IL-17 signalling pathway) in the L-PS vs. the PS group. Our results indicate that the infection of P. shigelloides can produce an inflammatory response, and probiotics could inhibit the inflammatory response caused by P. shigelloides to some extent.

/pdf/transcriptome-analysis-reveals-effect-of-dietary-probiotics-2q4878z7.pdf

Transcriptome Analysis Reveals Effect of Dietary Probiotics on Immune Response Mechanism in Southern Catfish (Silurus meridionalis) in Response to Plesiomonas shigelloides

Rongrong Wang

Papers

Application of poly(ethylene glycol)–distearoylphosphatidylethanolamine (PEG-DSPE) block copolymers and their derivatives as nanomaterials in drug delivery

Transcriptome Analysis Reveals Effect of Dietary Probiotics on Immune Response Mechanism in Southern Catfish (Silurus meridionalis) in Response to Plesiomonas shigelloides