Chitosan whisker grafted with oligo(lactic acid) nanoparticles via a green synthesis pathway: Potential as a transdermal drug delivery system.

Chitosan whisker (CSWK) grafted with oligo(lactic acid) (OLA) nanoparticles (NPs) in water is developed to aid transferring therapeutic agents through the skin in a transdermal drug delivery system. Although several works in the past have shown grafting of poly(lactic acid) onto chitosan, the present work shows a green grafting system for the first time. The nano-sized CSWK provided effective conjugation of lactic acid even in a heterogeneous water-based system followed by polycondensation to form OLA. The OLA chain length is controlled by the lactic acid content and modulates the lipophilicity of CSWK-OLA. This fine tunes not only the size of the NPs but also the encapsulation efficiency of the hydrophobic drug lidocaine. A detailed chemical structure analysis, including the factors related to the development of NPs, is presented and extends the studies to the model drug encapsulation and delivery.

Multiple extracellular vesicle types in peritoneal dialysis effluent are prominent and contain known biomarkers.

Peritoneal dialysis inevitability results in activation of inflammatory processes and its efficiency is highly variable between patients. An improved method to isolate biomarkers and study pathophysiological mechanisms in peritoneal dialysis effluent (PDE) is expected to be of much benefit for the development of this treatment approach and help with patient management. Extracellular vesicles (EVs) are released as part of normal cellular processes. Their proteome is expected to reflect both type and health of their cell of origin. Although there is a significant interest in using EVs for "liquid biopsies", little is reported of their presence or composition in plentiful dialysis waste fluids, including peritoneal dialysis effluent (PDE). Here we determined the presence of EVs in PDE and subsequently characterized their proteome. EVs were first isolated from PDE using differential centrifugation, then a further enrichment using size exclusion chromatography (SEC) was performed. The presence of EVs was demonstrated using transmission electron microscopy, and their particle counts were investigated using nanoparticle tracking analysis and dynamic light scattering. Using tandem mass spectrometry, marker proteins from three types of EVs i.e. apoptotic bodies, ectosomes, and exosomes were identified. The proteomic results demonstrated that the isolation of EVs by differential centrifugation helped enrich for over 2,000 proteins normally masked by abundant proteins in PDE such as albumin and SEC markedly further improved the isolation of low abundant proteins. Gene ontology analysis of all identified proteins showed the marked enrichment of exosome and membrane-associated proteins. Over 3,700 proteins were identified in total, including many proteins with known roles in peritoneal pathophysiology. This study demonstrated the prominence of EVs in PDE and their potential value as a source of biomarkers for peritoneal dialysis patients.

Cytoprotective effect of glutaraldehyde erythropoietin on HEK293 kidney cells after silver nanoparticle exposure.

The toxic effects from exposure to silver nanoparticles (AgNPs), which are broadly present in many consumer products, have long raised concerns. Many studies have focused on the mechanisms of nanosilver, which cause toxicity in human cells, but little is known about prevention of this type of injury. This study investigated the in vitro effects of glutaraldehyde erythropoietin (GEPO), a cytoprotective compound derived from erythropoietin, in terms of cell protection against AgNP-induced injury. HEK293 cells were pretreated with or without GEPO before administration of AgNPs. The protective effects of GEPO in this cell line were assessed by the percentage of viable cells, alterations of cell morphology, and the proliferative capability of the cells. In addition, we assessed the role of GEPO in lowering cellular oxidative stress and regulating expression of the anti-apoptotic protein Bcl2. The results showed rescue effects on the percentage of viable and proliferative cells among GEPO pretreated cells. Pretreatment with GEPO maintained the normal cell shape and ultrastructural morphology. Moreover, GEPO reduced the generation of reactive oxygen species in cells and activated expression of Bcl2, which are the major mechanisms in protection against cellular toxicity induced by AgNPs. In conclusion, our study showed that the cytotoxic effects from exposure to AgNPs can be prevented by GEPO.

Chitosan-phenylalanine-mPEG nanoparticles: From a single step water-based conjugation to the potential allergen delivery system.

The chemical modification to obtain biocompatible chitosan (CS) nanoparticles for the application in biological system is still on expectation. By simply mixing CS with hydroxybenzotriazole (HOBt), the CS aqueous solution obtained allows a successful single step conjugation of both hydrophobic biomolecules, i.e. phenylalanine (Phe), and hydrophilic polymers, i.e. poly(ethylene glycol) methyl ether (mPEG), on CS, in water at room temperature. The CS-Phe-mPEG nanoparticles (20-50nm) exhibit positive charge leading to an entrapment of negatively charged house dust mite allergen (HDM) extract (Dermatophagoides pteronyssinus). The HDM-entrapped CS-Phe-mPEG shows biocompatibility as evidenced from the cell viability, the ROS (reactive oxygen species) reduction, and the HaCaTs proliferation. The clinical implementation on the healthy- and HDM-allergic volunteers indicates that the HDM-entrapped CS-Phe-mPEG stimulates cell-mediated immune response in peripheral blood mononuclear cells (PBMCs) and favors T cell immune response as seen from the reduction of interferon-(IFN)-γ and interleukin-(IL)-10 in the PBMCs of the HDM-allergic volunteers.