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Biocompatible polypeptide microcapsules via templating mesoporous silica spheres.
Aimin Yu1, Ian R Gentle, Gao Qing Max Lu
1ARC Centre of Excellence for Functional Nanomaterials, The University of Queensland, 4072, Australia. a.yu@murdoch.edu.au
Journal of Colloid and Interface Science
|February 19, 2009
Summary
Researchers created biocompatible polypeptide microcapsules using layer-by-layer assembly on silica spheres. This method efficiently encapsulates enzymes, preserving their bioactivity for potential applications.
Area of Science:
- Biomaterials Science
- Nanotechnology
- Polymer Chemistry
Background:
- Layer-by-layer (LbL) self-assembly is a versatile technique for fabricating multilayer films.
- Mesoporous silica (MS) spheres offer a tunable template for nanostructure fabrication.
- Biocompatible polypeptide coatings are desirable for drug delivery and biomedical applications.
Purpose of the Study:
- To develop a method for creating biocompatible poly(L-lysine)/poly(L-glutamic acid) (PLL/PGA) multilayer films on MS spheres.
- To investigate the formation and properties of these multilayer films.
- To establish a general approach for encapsulating enzymes within hollow polypeptide microcapsules with high loading and retained bioactivity.
Main Methods:
- Stepwise formation of PLL/PGA multilayer films on MS spheres using LbL self-assembly.
- In-situ Quartz Crystal Microbalance (QCM) to monitor film growth.
- Zeta-potential measurements to characterize surface charge dynamics.
- Dissolution of silica cores using hydrofluoric acid (HF) to form hollow capsules.
- Encapsulation of various enzymes using preloaded MS spheres as templates.
Main Results:
- LbL self-assembly resulted in nonlinear (exponential) growth of PLL/PGA multilayer films at pH 5.5 and 7.0.
- Charge-overcompensation at each adsorption step facilitated subsequent polypeptide adsorption.
- Hollow polypeptide microcapsules were successfully fabricated by silica core removal.
- Enzymes were encapsulated with high loading efficiency and retained significant bioactivity, regardless of size.
Conclusions:
- The LbL self-assembly technique provides a robust method for constructing biocompatible polypeptide multilayer films on MS spheres.
- This approach enables the creation of hollow polypeptide microcapsules suitable for enzyme encapsulation.
- The developed method offers a general and effective strategy for encapsulating enzymes, preserving their bioactivity for potential biomedical applications.
