title: Effect of shear on physicochemical properties of matrix metalloproteinase responsive silk-elastinlike hydrogels.
abstract: Silk-elastinlike protein polymers (SELPs) have been fabricated as matrices for controlled delivery of bioactive agents. In this application the need for an environmentally responsive, degradable polymer has risen to improve treatment outcomes. To satisfy this need, we have designed, synthesized, and expressed SELPs with matrix metalloproteinase (MMP) degradable sequences inserted in distinct regions of the polymer backbone. Upon characterization of the physicochemical properties of newly synthesized analogs, it was determined that conditioning of the polymers was necessary for normalization of batch properties, and to generate a more robust polymer network suitable for delivery. In this report we have examined the use of shear stress to condition synthesized material prior to application as a controlled release matrix. The application of high shear to SELPs results in significant changes in physiochemical properties as assayed by swelling ratio, soluble fraction release, rate of gel formation, stiffness of hydrogels, and nanoparticle release from matrices. These observed changes in material characteristics may be caused by the removal of semi-stable secondary and tertiary structures from single polymer strands leading to a more robust hydrogel with greater intermolecular interaction.
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT, USA; Utah Center for Nanomedicine, Nano Institute of Utah, University of Utah, Salt Lake City, UT, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Price
authors.affiliation: Utah Center for Nanomedicine, Nano Institute of Utah, University of Utah, Salt Lake City, UT, USA; Department of Bioengineering, University of Utah, Salt Lake City, UT, USA.
authors.forename: Azadeh
authors.initials: A
authors.lastname: Poursaid
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Cappello
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, UT, USA; Utah Center for Nanomedicine, Nano Institute of Utah, University of Utah, Salt Lake City, UT, USA; Department of Bioengineering, University of Utah, Salt Lake City, UT, USA. Electronic address: hamid.ghandehari@pharm.utah.edu.
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Ghandehari
mesh_terms: D000596:Amino Acids / Q000032:analysis; D020100:Hydrogels / Q000737:chemistry; D020782:Matrix Metalloproteinases / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D012212:Rheology; D013314:Stress, Mechanical
chemical_list: D000596:Amino Acids; D020100:Hydrogels; D011506:Proteins; C573821:SELP 815K; D020782:Matrix Metalloproteinases
keywords: Drug delivery; Matrix metalloproteinase; Recombinant polymers; Shear; Silk-elastinlike polymers
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