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Layer-by-Layer Surface Modification of Alendronate-Loaded Polyester Microparticles-Enabling Protein Immobilization
Tomasz Urbaniak1, Witold Musiał1
1Department of Physical Chemistry and Biophysics, Pharmaceutical Faculty, Wrocław Medical University, Borowska 211, 50-556 Wrocław, Poland.
Polymers
|November 26, 2022
Summary
Researchers developed functionalized polyester microcarriers for targeted drug delivery by coating them with polyelectrolyte shells. This modification enhances macromolecule coupling for improved drug carrier systems.
Area of Science:
- Biomaterials Science
- Drug Delivery Systems
- Surface Chemistry
Background:
- Polyester micro- and nano- carriers have inert surfaces, hindering modification for targeted drug delivery.
- Developing surface moieties for macromolecule coupling is essential for advanced drug delivery systems.
- Adsorption of charged macromolecules offers a mild method for surface activation.
Purpose of the Study:
- To functionalize alendronate-loaded polyester microcarriers with polyelectrolyte shells for protein immobilization.
- To assess the stability and protein coupling efficiency of different polyelectrolyte coatings.
- To evaluate the potential of these modified carriers in targeted drug delivery applications.
Main Methods:
- Layer-by-layer assembly of polyelectrolyte shells (chitosan/heparin, polyallylamine/heparin, polyethyleneimine/heparin) onto polyester microcores (PCL, PLA-co-PCL, PLGA).
- Electrokinetic potential measurements to confirm coating deposition and assess charge alterations.
- Stability tests under physiological-like conditions (pH, phosphate ions).
- Fluorescence assays using EDC/NHS click reaction for model protein (lysozyme) immobilization efficiency.
- Immobilization of model IgG on selected carriers and affinity assessment.
Main Results:
- Successful deposition of all polyelectrolyte coating variants was confirmed by electrokinetic potential measurements.
- Polyethyleneimine/heparin (PEI/HEP) assembly showed stability in physiological conditions; polyallylamine/heparin (PAH/HEP) disassembled in phosphate ions, and chitosan/heparin (CHIT/HEP) had limited stability at pH 7.4.
- Satisfying reaction efficiency was observed for fluorescein-tagged lysozyme immobilization on all shell variants via EDC/NHS click chemistry.
- Poly-ε-caprolactone (PCL) cores coated with CHIT/HEP tetralayer demonstrated suitability for model IgG immobilization.
- Immobilized antibodies exhibited moderate affinity to fluorescent IgG binding protein.
Conclusions:
- Polyelectrolyte multilayer coatings can functionalize inert polyester microcarriers for drug delivery.
- The stability of coatings varies with composition and environmental conditions.
- The developed system shows promise for targeted drug delivery applications requiring protein immobilization.
