title: Spontaneous loading of positively charged macromolecules into alginate-templated polyelectrolyte multilayer microcapsules.
abstract: A simple and high-efficiency approach to loading macromolecules into microscale carriers is presented. Calcium-cross-linked alginate hydrogel microspheres were fabricated by an emulsification technique and then used as negatively charged templates to form polyelectrolyte multilayer coatings. A calcium ion chelator, EDTA, was used to free the Ca(2+)-cross-linked alginate hydrogel within {poly(allylamine hydrochloride)/poly (styrene sulfonate)}(4) ({PAH/PSS}(4)) coating, allowing partial release of alginate. The retention of alginate in {PAH/PSS}(4) microcapsule was confirmed by FTIR spectroscopy and confocal microscopy. Real-time confocal microscopy was used to investigate the loading process of positively charged macromolecules (dextran-amino, and peroxidase) into alginate-templated microcapsules, which showed the loading occurred in <2 min for dextran-amino and <10 min for peroxidase, respectively. A high loading efficiency of 25 mug peroxidase in approximately 1.0 x 10(7) microcapsules (2.5 pg POx/capsule) was achieved with a low concentration of peroxidase loading solution (10 mug/mL). This spontaneous loading technique for encapsulating positively charged molecules in alginate-templated polyelectrolyte microcapsules shows strong potential for biosensor and drug delivery applications.
authors: Institute for Micromanufacturing and Biomedical Engineering Program, Louisiana Tech University, 911 Hergot Avenue, Ruston, Louisiana 71272, USA. hzhu@latech.edu
authors: Huiguang
authors: H
authors: Zhu
authors: Rohit
authors: R
authors: Srivastava
authors: Michael J
authors: MJ
authors: McShane
mesh_terms: D000464:Alginates / Q000737:chemistry*; D002214:Capsules; D003911:Dextrans / Q000737:chemistry; D004573:Electrolytes / Q000737:chemistry*; D018613:Microscopy, Confocal; D008863:Microspheres; D010544:Peroxidases / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000464:Alginates; D002214:Capsules; D003911:Dextrans; D004573:Electrolytes; D010544:Peroxidases