| A number of innovative techniques were developed to carry genetic material into cells, making gene therapy one of the most active fields in biotechnology. Interest in this domain is due to two factors: the therapeutic potential of the approach and lack of delivery systems which fulfil all requirements for clinical implementation. The advent of new nanotechnologies, combined with a better understanding of biological processes, enables the development of more sophisticated tools for delivery of genetic material to cells. This thesis reports on these novel nanocarriers with promising features for gene delivery.;The second part of the thesis focuses on design and assembly of novel non-viral nanocarriers for gene delivery applications. The characterization and optimization of a delivery system formulated with chitosan and hyaluronic acid are presented, providing an original and viable option to transfer genetic material into cells. The functionalization of the chitosan-based nanocarriers, to obtain an ultraviolet light stimuli-sensitive gene delivery system, is also accomplished, allowing a better control of the spatiotemporal release of genetic material. Validation of the assembly, combined with a proof of concept of nanocarrier functionality, is demonstrated.;The research conducted during this PhD thesis represents a significant step towards the development of a new generation of smart carriers, with safer and more efficient delivery of therapeutics. It provides the foundation for further development of a low-cost and easy to produce delivery system, with readily available, biocompatible and biodegradable materials with tunable properties.;The first part of this thesis describes the state of the art of gene delivery approaches relevant to the research conducted throughout this PhD project. Major gene delivery systems are described to give insight into current advancements, limitations and challenges in the field. This section is followed by a review of therapeutic agent delivery using chitosan-based nanocarriers. In this review, we provide a summary of the most important progress concerning the use of chitosan to produce nanocarriers for several forms of delivery; this includes small molecules, proteins and genetic material. New trends in the area of gene delivery such as the development of stimuli-sensitive devices are described in a separate chapter in order to illustrate the new trends in the field of therapeutic delivery. Together, these three chapters provide a background to better understand the motivation behind the development of the nanocarriers. |
