PURPOSE: To evaluate if lyophilization can be used to obtain a dry formulation of polyelectrolyte microcapsules, which have emerged as a new class of microparticles for the encapsulation and delivery of biomacromolecules. METHODS: Microcapsules composed of dextran sulfate and poly-L-arginine were obtained by coating CaCO(3) microparticles by means of the layer-by-layer technique. Microcapsules were lyophilized using different stabilizers; intactness was checked by CLSM and SEM. Horseradish peroxidase was encapsulated as model enzyme and retained activity after freeze-drying was determined using a fluorescence assay. Ovalbumin was encapsulated as model antigen; immunogenicity after lyophilization was evaluated in vitro by a T-cell proliferation assay and in vivo by measuring the antibody titer in mice. RESULTS: The results clearly demonstrate the necessity of using polyols in the formulation to prevent rupture of the microcapsules and to preserve the activity of encapsulated enzymes. Lyophilized microcapsules appeared as a promising adjuvant for antigen delivery, as both in vitro as in vivo assays showed higher immune activation compared to free antigen. CONCLUSIONS: Lyophilization is a promising strategy towards improved stability of protein-loaded microcapsules.
PURPOSE: To evaluate if lyophilization can be used to obtain a dry formulation of polyelectrolyte microcapsules, which have emerged as a new class of microparticles for the encapsulation and delivery of biomacromolecules. METHODS: Microcapsules composed of dextran sulfate and poly-L-arginine were obtained by coating CaCO(3) microparticles by means of the layer-by-layer technique. Microcapsules were lyophilized using different stabilizers; intactness was checked by CLSM and SEM. Horseradish peroxidase was encapsulated as model enzyme and retained activity after freeze-drying was determined using a fluorescence assay. Ovalbumin was encapsulated as model antigen; immunogenicity after lyophilization was evaluated in vitro by a T-cell proliferation assay and in vivo by measuring the antibody titer in mice. RESULTS: The results clearly demonstrate the necessity of using polyols in the formulation to prevent rupture of the microcapsules and to preserve the activity of encapsulated enzymes. Lyophilized microcapsules appeared as a promising adjuvant for antigen delivery, as both in vitro as in vivo assays showed higher immune activation compared to free antigen. CONCLUSIONS: Lyophilization is a promising strategy towards improved stability of protein-loaded microcapsules.
Authors: B Neu; A Voigt; R Mitlöhner; S Leporatti; C Y Gao; E Donath; H Kiesewetter; H Möhwald; H J Meiselman; H Bäumler Journal: J Microencapsul Date: 2001 May-Jun Impact factor: 3.142
Authors: Bruno G De Geest; Andre G Skirtach; Arif A Mamedov; Alexei A Antipov; Nicholas A Kotov; Stefaan C De Smedt; Gleb B Sukhorukov Journal: Small Date: 2007-05 Impact factor: 13.281
Authors: Gleb B Sukhorukov; Andrey L Rogach; Malgorzata Garstka; Sebastian Springer; Wolfgang J Parak; Almudena Muñoz-Javier; Oliver Kreft; Andre G Skirtach; Andrei S Susha; Yannic Ramaye; Raghavendra Palankar; Mathias Winterhalter Journal: Small Date: 2007-06 Impact factor: 13.281
Authors: Stefaan De Koker; Thomas Naessens; Bruno G De Geest; Pieter Bogaert; Jo Demeester; Stefaan De Smedt; Johan Grooten Journal: J Immunol Date: 2009-11-30 Impact factor: 5.422