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Silk nanospheres and microspheres from silk/pva blend films for drug delivery

Paper ID Volume ID Publish Year Pages File Format Full-Text
9805 648 2010 11 PDF Available
Title
Silk nanospheres and microspheres from silk/pva blend films for drug delivery
Abstract

Silk fibroin protein-based micro- and nanospheres provide new options for drug delivery due to their biocompatibility, biodegradability and their tunable drug loading and release properties. In the present study, we report a new aqueous-based preparation method for silk spheres with controllable sphere size and shape. The preparation was based on phase separation between silk fibroin and polyvinyl alcohol (PVA) at a weight ratio of 1/1 and 1/4. Water-insoluble silk spheres were easily obtained from the blend in a three step process: (1) air-drying the blend solution into a film, (2) film dissolution in water and (3) removal of residual PVA by subsequent centrifugation. In both cases, the spheres had approximately 30% beta-sheet content and less than 5% residual PVA. Spindle-shaped silk particles, as opposed to the spherical particles formed above, were obtained by stretching the blend films before dissolving in water. Compared to the 1/1 ratio sample, the silk spheres prepared from the 1/4 ratio sample showed a more homogeneous size distribution ranging from 300 nm up to 20 μm. Further studies showed that sphere size and polydispersity could be controlled either by changing the concentration of silk and PVA or by applying ultrasonication on the blend solution. Drug loading was achieved by mixing model drugs in the original silk solution. The distribution and loading efficiency of the drug molecules in silk spheres depended on their hydrophobicity and charge, resulting in different drug release profiles. The entire fabrication procedure could be completed within one day. The only chemical used in the preparation except water was PVA, an FDA-approved ingredient in drug formulations. Silk micro- and nanospheres reported have potential as drug delivery carriers in a variety of biomedical applications.

Keywords
Silk; Fibroin; Polyvinyl alcohol (PVA); Nanospheres; Microspheres; Drug release
First Page Preview
Silk nanospheres and microspheres from silk/pva blend films for drug delivery
Publisher
Database: Elsevier - ScienceDirect
Journal: Biomaterials - Volume 31, Issue 6, February 2010, Pages 1025–1035
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering