Progressive Saturation Improves the Encapsulation of Functional Proteins in Nanoscale Polymer Vesicles.
Pharm Res
; 33(3): 573-89, 2016 Mar.
Article
em En
| MEDLINE
| ID: mdl-26508477
ABSTRACT
PURPOSE:
To develop a technique that maximizes the encapsulation of functional proteins within neutrally charged, fully PEGylated and nanoscale polymer vesicles (i.e., polymersomes).METHODS:
Three conventional vesicle formation methods were utilized for encapsulation of myoglobin (Mb) in polymersomes of varying size, PEG length, and membrane thickness. Mb concentrations were monitored by UV-Vis spectroscopy, inductively coupled plasma optical emission spectroscopy (ICP-OES) and by the bicinchoninic acid (BCA) assay. Suspensions were subject to protease treatment to differentiate the amounts of surface-associated vs. encapsulated Mb. Polymersome sizes and morphologies were monitored by dynamic light scattering (DLS) and by cryogenic transmission electron microscopy (cryo-TEM), respectively. Binding and release of oxygen were measured using a Hemeox analyzer.RESULTS:
Using the established "thin-film rehydration" and "direct hydration" methods, Mb was found to be largely surface-associated with negligible aqueous encapsulation within polymersome suspensions. Through iterative optimization, a novel "progressive saturation" technique was developed that greatly increased the final concentrations of Mb (from < 0.5 to > 2.0 mg/mL in solution), the final weight ratio of Mb-to-polymer that could be reproducibly obtained (from < 1 to > 4 w/w% Mb/polymer), as well as the overall efficiency of Mb encapsulation (from < 5 to > 90%). Stable vesicle morphologies were verified by cryo-TEM; the suspensions also displayed no signs of aggregate formation for > 2 weeks as assessed by DLS. "Progressive saturation" was further utilized for the encapsulation of a variety of other proteins, ranging in size from 17 to 450 kDa.CONCLUSIONS:
Compared to established vesicle formation methods, "progressive saturation" increases the quantities of functional proteins that may be encapsulated in nanoscale polymersomes.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Polímeros
/
Portadores de Fármacos
/
Proteínas
/
Nanopartículas
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article