Layer by layer films for biomedical applications

Gündoğan, Zeynep
Layer-by-layer (LbL) deposition is a useful method for the preparation of ultra-thin films. Using this technique, very thin films, starting from few Angstroms up to few micrometers can be obtained. Lately, most of the polyelectrolyte applications have employed natural polymers, mainly anionic alginate (ALG) and cationic chitosan (CHI), which have been playing an important role in biomedical research. Besides their attractive biocompatibility, biodegradability, abundance and ease of processing, these polymers have a potential ability to mimic some biological microenvironments. Calcium phosphate compounds are also preferable materials because of their similarity to natural bone minerals, and used in orthopedic and dental applications as grafts, fillings, as carrriers for hormons, growth factors or drugs which all enhance the differentiation and proliferation of cells and in total formation of new bone tissue. Gelatin (GEL) is also an important polymer used in polyelectrolyte multilayers. Layer-by-layer growth of CHI/GEL and ALG can be a good candidate for local antibiotic treatment. In this work, firstly, multilayered nanocomposites were produced as LbL two-dimensional (2D) films by using chitosan (CHI) and alginate (ALG) as interacting polymers as well as some salt solutions to obtain nano size calcium phosphates niches within each layer. Optimum film formation conditions were determined by using different parameters such as pH of the medium, salt concentration and layer deposition order. The produced films were tested for Saos-2 cell attachment and proliferation. In the second part of the study, microlayer films were prepared via solvent casting method. These films contained three layers and some loaded with a model antibiotic namely ceftriaxone sodium (CS). The films were prepared either without drug as controls, or CS loaded in alginate layer and coded as CHI/ALG/CHI, CHI/ALG-CS/CHI, CHI-GEL/ALG/CHI-GEL and CHI-GEL/ALG-CS/CHI-GEL. Mechanical properties of the films and release kinetics of CS from the films were investigated. It was concluded that, formation of nano LbL films on implant surfaces to make them biocompatible is possible, and microfilms prepared by solvent casting can be good candidates as drug carrier devices.
Citation Formats
Z. Gündoğan, “Layer by layer films for biomedical applications,” M.S. - Master of Science, Middle East Technical University, 2015.