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運用人類血小板及血小板微粒作為抗癌藥物傳遞系統之研究

為了解決ADR HK的問題，作者吳玉雯 這樣論述：

Background:Human platelets (PLTs) and PLT-derived extracellular vesicles (PEVs) released upon thrombin activation express receptors that interact with tumour cells and, thus, can serve as a delivery platform of anti-cancer agents. Drug-loaded nanoparticles coated with PLT membranes were demonstrate

d to have improved targeting efficiency to tumours, but remain impractical for clinical translation. PLTs and PEVs targeted drug delivery systems (TDDS) should facilitate clinical developments if clinical-grade procedures can be developed.Materials and methods:PLT from therapeutic-grade PLT concentr

ate (PC; N > 50) were loaded with doxorubicin (DOX) and stored at -80 °C (PLT-DOX) with 6% dimethyl sulfoxide (frozen PLT-DOX). Surface markers and PLT functional activity of frozen PLT-DOX was confirmed by Western blot and thromboelastography (TEG), respectively. The morphology of fresh and frozen

PLT and PLT-DOX was observed by scanning electron microscopy (SEM). The content of tissue factor-expressing cancer-derived extracellular vesicles (TF-EV) present in conditioned medium (CM) of breast cancer cells cultures was measured. The drug release by fresh and frozen PLT-DOX triggered by various

pH and CM was determined by high performance liquid chromatography (HPLC). The cellular uptake of DOX from PLTs was observed by deconvolution microscopy. The cytotoxicities of PLT-DOX, frozen PLT-DOX, DOX and liposomal DOX on breast, lung and colon cancer cells were analyzed by CCK-8 assay.We compa

red extrusion, 3 cycles of freeze and thaw (freeze-thaw), sonication, and incubation to produce PEVs from human cryopreserved PLTs. The morphology of PEVs measured by SEM. The size distribution and the amount of particles in isolated PEVs analyzed by dynamic light scattering (DLS) and nanoparticle t

racking analysis (NTA). In addition, PEVs subjected to extrusion, freeze-thaw and sonication were loaded with anti-cancer drug, DOX, by incubation for 24 h and purification with chromatography to remove unbound DOX (PEV-DOX). The encapsulation efficiency of DOX in PEVs measured by fluorospectrometry

. The surface markers and procoagulant functional activity of PEV-DOX was confirmed by Western blot and MP-PS activity assay, respectively. The cellular uptake of PEVs by three breast cancer cell lines including MCF7, MDA-MB-231 and MCF7/ADR measured by flow cytometry and ImageXpress Pico Automated

Cell Imaging System. The cytotoxicities of PEV-DOX, DOX and liposomal DOX on breast cancer cells were analyzed by CCK-8 assay.Results:15~36 × 106 molecules of DOX could be loaded in each PLT within 3 to 9 days after collection. The characterization and bioreactivity of frozen PLT-DOX were preserved,

as evidenced by (a) microscopic observations, (b) preservation of important PLT membrane markers CD41, CD61, protease activated receptor-1, (c) functional activity, (d) reactivity to TF-EV, and (e) efficient generation of PEVs upon thrombin activation. The transfer of DOX from frozen PLTs to cancer

cells was achieved within 90 min, and stimulated by TF-EV and low pH. The frozen PLT-DOX formulation was 7~23-times more toxic to three cancer cells than liposomal DOX.Morphology of PEVs by SEM was spheroid. Approximate 496 PEVs/PLT and 493 PEVs/PLT could be generated by extrusion and sonication, c

ompared to 145 PEVs/PLT and 33 PEVs/PLT by freeze/thaw and incubation, respectively. The encapsulation efficiency of DOX into PEVs treated with freeze-thaw (11%) was higher than extrusion (11%) and sonication (13%) after incubation followed by purification by Sephadex G-25 chromatography measured by

fluorospectrometry. Western blot evidenced that DOX loading did not influence expression level of PEV membrane surface markers (CD41, CD42a, CD62P, CD9 and CD63). The population sizes and concentration of PEVs and PEV-DOXs by DLS and NTA was 120-150 nm and 1.2-6.2 x 1011 particles per mL, respectiv

ely. In addition, drug loading also did not increase the risk of procoagulant activity. PEVs uptake analyzed by flow-cytometry showed strong internalization by drug resistant breast cancer cell lines, MCF7/ADR, compared to MCF7 cells and MDA-MB-231 cells. Cytotoxicity data showed that higher anti-ca

ncer activity of PEV-DOX on MCF7/ADR cells than other two breast cancer cells.Conclusions:Frozen PLT-DOX and PEV-DOX can be prepared under clinically compliant conditions preserving the membrane functionality for anti-cancer therapy. These findings open perspectives for translational applications of

PLT-based DDS.