Document Detail

Permeability and micromechanical properties of silk ionomer microcapsules.
MedLine Citation:
PMID:  22834790     Owner:  NLM     Status:  MEDLINE    
We studied the pH-responsive behavior of layer-by-layer (LbL) microcapsules fabricated from silk fibroin chemically modified with different poly amino acid side chains: cationic (silk-poly L-lysine, SF-PL) or anionic (silk-poly-L-glutamic acid, SF-PG). We observed that stable ultrathin shell microcapsules can be assembled with a dramatic increase in swelling, thickness, and microroughness at extremely acidic (pH < 2.5) and basic (pH > 11.0) conditions without noticeable disintegration. These changes are accompanied by dramatic changes in shell permeability with a 2 orders of magnitude increase in the diffusion coefficient. Moreover, the silk ionomer shells undergo remarkable softening with a drop in Young's modulus by more than 1 order of magnitude due to the swelling, stretching, and increase in material porosity. The ability to control permeability and mechanical properties over a wide range for the silk-based microcapsules, with distinguishing stability under harsh environmental conditions, provides an important system for controlled loading and release and applications in bioengineering.
Chunhong Ye; Irina Drachuk; Rossella Calabrese; Hongqi Dai; David L Kaplan; Vladimir V Tsukruk
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2012-08-07
Journal Detail:
Title:  Langmuir : the ACS journal of surfaces and colloids     Volume:  28     ISSN:  1520-5827     ISO Abbreviation:  Langmuir     Publication Date:  2012 Aug 
Date Detail:
Created Date:  2012-08-21     Completed Date:  2012-12-28     Revised Date:  2014-04-08    
Medline Journal Info:
Nlm Unique ID:  9882736     Medline TA:  Langmuir     Country:  United States    
Other Details:
Languages:  eng     Pagination:  12235-44     Citation Subset:  IM    
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MeSH Terms
Amino Acids / chemistry
Fibroins / chemistry*
Hydrogen-Ion Concentration
Mechanical Processes*
Polyethyleneimine / chemistry
Polymers / chemistry*
Grant Support
Reg. No./Substance:
0/Amino Acids; 0/Capsules; 0/Polymers; 9002-98-6/Polyethyleneimine; 9007-76-5/Fibroins

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