کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
12106 778 2006 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
pH triggered release of protective poly(ethylene glycol)-b-polycation copolymers from liposomes
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی بیو مهندسی (مهندسی زیستی)
پیش نمایش صفحه اول مقاله
pH triggered release of protective poly(ethylene glycol)-b-polycation copolymers from liposomes
چکیده انگلیسی

Triggered release of adsorbed polymers from liposomes enables protection against immune recognition during circulation and subsequent intracellular delivery of DNA. Polycationic blocks, poly[2-(dimethylamino) ethyl methacrylate] (DMAEMA) (0.8, 3.1, 4.9, or 9.8 kg/mol) or polylysine (K) (3 kg/mol), act as anchors for poly(ethylene glycol) (PEG) (2 or 5 kg/mol) protective blocks. In addition, a copolymer with 15 strictly alternating blocks of PEG (2 kg/mol) and cationic amine sites was evaluated as a protective coating. Incorporation of 1,2-dioleoyl-3-dimethylammonium-propane, a titratable lipid with a pKa of ∼6.7, allows the liposome's net charge to increase as the pH shifts from 7.4 in the bloodstream to 5.5 in the endosome. The increased net liposome cationicity results in decreased cationic polymer adsorption. The EMPEG113–DMAEMA31 and EMPEG113–DMAEMA62 association constants decrease from 3.1 and 6.2 (mg/m2)/(mg/ml) at pH 7.4 to 1.7 and 3.2 (mg/m2)/(mg/ml) at pH 5.5, respectively. However, EMPEG45–DMAEMA5, EMPEG45–DMAEMA20, and EMPEG45–N–DP15 did not show a strong response to changes in pH. Cationic polymer adsorption exceeds calculated values for liposome neutralization, resulting in adsorption profiles in the brush regime.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biomaterials - Volume 27, Issue 12, April 2006, Pages 2599–2608
نویسندگان
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