More efficient drug delivery system and formulation with less adverse effects are needed for the clinical application of broad-spectrum antineoplastic agent doxorubicin (DOX). Here we obtained outer-membrane vesicles (OMVs), a nano-sized proteoliposomes naturally released by Gram-negative bacteria, from attenuated Klebsiella pneumonia and prepared doxorubicin-loaded O0MVs (DOX-OMV). Confocal microscopy and in vivo distribution study observed that DOX encapsulated in OMVs was efficiently transported into NSCLC A549 cells. DOX-OMV resulted in intensive cytotoxic effects and cell apoptosis in vitro as evident from MTT assay, Western blotting and flow cytometry due to the rapid cellular uptake of DOX. In A549 tumor-bearing BALB/c nude mice, DOX-OMV presented a substantial tumor growth inhibition with favorable tolerability and pharmacokinetic profile, and TUNEL assay and H&E staining displayed extensive apoptotic cells and necrosis in tumor tissues. More importantly, OMVs’ appropriate immunogenicity enabled the recruitment of macrophages in tumor microenvironment which might synergize with their cargo DOX in vivo . Our results suggest that OMVs can not only function as biological nanocarriers for chemotherapeutic agents but also elicit suitable immune responses, thus having a great potential for the tumor chemoimmunotherapy.

No abstract

This work develops a novel electrochemical approach for detection of the extracellular oxygen released from human erythrocytes. The sensing is based on the bioelectrocatalytic system of graphene integrated with laccase (Lac) and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) toward the reduction of oxygen. ABTS and laccase are assembled on the surface of graphene, which is synthesized by a chemistry route, utilizing the pi-pi and electrostatic interactions of these components. Transmission electron microscopy (TEM), atomic force microscopy (AFM), and FT-IR spectroscopy demonstrate that graphene has been successfully synthesized, and ABTS and laccase have been effectively assembled on a graphene surface with the formation of Lac-ABTS-graphene hybrid. The voltammetric results indicate that ABTS can be used as a redox mediator when it is in immobilized form. The hybrid deposited on the glassy carbon (GC) electrode is demonstrated to be a good bioelectrocatalyst for the reduction of oxygen with inherent enzyme activity, accepted stability, high half-wave potential (ca.670 mV vs NHE), and unimpeded electrical communication to the copper redox sites of laccase. Therefore, this study has not only established a novel approach of detection of extracellular oxygen but also provided a general route for fabricating a graphene-based biosensing platform via assembling enzymes/proteins on a graphene surface.

Poly(lactic-co-glycolic acid) (PLGA) has garnered increasing attention as a candidate drug delivery polymer owing to its favorable properties, including its excellent biocompatibility, biodegradability, nontoxicity, non-immunogenicity, and mechanical strength. PLAG are specifically used as microspheres for the sustained/controlled and targeted delivery of hydrophilic or hydrophobic drugs, as well as biological therapeutic macromolecules, including peptide and protein drugs. PLGAs with different molecular weights, lactic acid (LA)/glycolic acid (GA) ratios, and end groups exhibit unique release characteristics, which is beneficial for obtaining diverse therapeutic effects. This review aims to analyze the composition of PLGA microspheres, and understand the manufacturing process involved in their production, from a quality by design perspective. Additionally, the key factors affecting PLGA microsphere development are explored as well as the principles involved in the synthesis and degradation of PLGA and its interaction with active drugs. Further, the effects elicited by microcosmic conditions on PLGA macroscopic properties, are analyzed. These conditions include variations in the organic phase (organic solvent, PLGA, and drug concentration), continuous phase (emulsifying ability), emulsifying stage (organic phase and continuous phase interaction, homogenization parameters), and solidification process (relationship between solvent volatilization rate and curing conditions). The challenges in achieving consistency between batches during manufacturing are addressed, and continuous production is discussed as a potential solution. Finally, potential critical quality attributes are introduced, which may facilitate the optimization of process parameters.