title: Prolonged Release of Bioactive Model Proteins from Anionic Microgels Fabricated with a New Microemulsion Approach.
abstract: OBJECTIVE
  Therapeutic proteins have become an integral part of health care. However, their controlled delivery remains a challenge. Protein function depends on a delicate three dimensional structure, which can be damaged during the fabrication of controlled release systems. This study presents a microgel-based controlled release system capable of high loading efficiencies, prolonged release and retention of protein function.
  
  
  METHODS
  A new DMSO/Pluronic microemulsion served as a reaction template for the crosslinking of poly(acrylic acid) and oligo (ethylene glycol) to form microgels. Poly(acylic acid) molecular weights and microgel crosslinking densities were altered to make a series of microgels. Microgel capacity to capture and retain proteins of different sizes and isoelectric points, to control their release rate (over ~30 days) and to maintain the biofunctionality of the released proteins were evaluated.
  
  
  RESULTS
  Microgels of different sizes and morphologies were synthesized. Loading efficiencies of 100% were achieved with lysozyme in all formulations. The loading efficiency of all other proteins was formulation dependent. Release of lysozyme was achieved for up to 30 days and the released lysozyme retained over 90% of its activity.
  
  
  CONCLUSIONS
  High loading efficiencies and prolonged release of different proteins was achieved. Furthermore, lysozyme's functionality remained uncompromised after encapsulation and release. This work begins to lay the foundation for a broad platform for the delivery of therapeutic proteins.
authors.affiliation: Meinig School of Biomedical Engineering, Cornell University, 147 Weill Hall, Ithaca, New York, 14853, USA.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Rios
authors.affiliation: Meinig School of Biomedical Engineering, Cornell University, 147 Weill Hall, Ithaca, New York, 14853, USA.
authors.forename: Gongcheng
authors.initials: G
authors.lastname: Lu
authors.affiliation: Department of Biological and Environmental Engineering, Cornell University, Ithaca, New York, 14853, USA.
authors.forename: Na Eun
authors.initials: NE
authors.lastname: Seo
authors.affiliation: Department of Biological and Environmental Engineering, Cornell University, Ithaca, New York, 14853, USA.
authors.forename: Tamara
authors.initials: T
authors.lastname: Lambert
authors.affiliation: Meinig School of Biomedical Engineering, Cornell University, 147 Weill Hall, Ithaca, New York, 14853, USA. dap43@cornell.edu.|School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, 14853, USA. dap43@cornell.edu.
authors.forename: David
authors.initials: D
authors.lastname: Putnam
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000818:Animals; D000838:Anions; D003692:Delayed-Action Preparations / Q000737:chemistry*; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004655:Emulsions / Q000737:chemistry; D019855:Ethylene Glycol / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D006801:Humans; D009113:Muramidase / Q000008:administration & dosage; D020442:Poloxamer / Q000737:chemistry; D011506:Proteins / Q000008:administration & dosage*
chemical_list: D000180:Acrylic Resins; D000838:Anions; D003692:Delayed-Action Preparations; D004655:Emulsions; D005782:Gels; D011506:Proteins; D020442:Poloxamer; C006903:carbopol 940; D009113:Muramidase; D019855:Ethylene Glycol; D004121:Dimethyl Sulfoxide
keywords: bioactive proteins; microemulsion; microgels; prolonged release