PEGylated polyethyleneimine-entrapped gold nanoparticles for enhanced and targeted gene delivery applications

Gene therapy, which involves the transfer of nucleic acid into target cells in patients, has become one of the most important and widely explored strategies to treat a variety of diseases, such as cancer, infectious diseases and genetic disorders. Relative to viral vectors that have high immunogenicity, toxicity and oncogenicity, non-viral vectors have gained a lot of interest in recent years. This is largely due to their ability to mimic viral vector features including the capacity to overcome extra- and intra-cellular barriers and to enhance transfection efficiency. Polyethyleneimine (PEI) has been extensively investigated as a non-viral vector. This cationic polymer, which is able to compact nucleic acid through electrostatic interactions and to transport it across the negatively charged cell membranes, has been shown to effectively transfect nucleic acid into different cell lines. Moreover, entrapment of gold nanoparticles (Au NPs) into such an amine-terminated polymer template has been shown to significantly enhance gene transfection efficiency. In this work, a novel non-viral nucleic acid vector system for enhanced and targeted nucleic acid delivery applications was developed. The system was based on the functionalization of PEI with folic acid (FA; for targeted delivery to cancer cells overexpressing FA receptors on their surface) using polyethylene glycol (PEG) as a linker molecule. This was followed by the preparation of PEI-entrapped Au NPs (Au PENPs; for enhancement of transfection efficiency). In the synthesis process, the primary amines of PEI were first partially modified with fluorescein isothiocyanate (FI) using a molar ratio of 1:7. The formed PEI-FI conjugate was then further modified with either PEG or PEGylated FA using a molar ratio of 1:1. This process was finally followed by entrapment of Au NPs into the modified polymers. The resulting conjugates and Au PENPs were characterized by several techniques, namely Nuclear Magnetic Resonance, Dynamic Light Scattering and Ultraviolet-Visible Spectroscopy, to assess their physicochemical properties. In the cell biology studies, the synthesized conjugates and their respective Au PENPs were shown to be non-toxic towards A2780 human ovarian carcinoma cells. The role of these materials as gene delivery agents was lastly evaluated. In the gene delivery studies, the A2780 cells were successfully transfected with plasmid DNA using the different vector systems. However, FA-modification and Au NPs entrapment were not determinant factors for improved transfection efficiency. In the gene silencing studies, on the other hand, the Au PENPs were shown to effectively deliver small interfering RNA, thereby reducing the expression of the B-cell lymphoma 2 protein. Based on these results, we can say that the systems synthesized in this work show potential for enhanced and targeted gene therapy applications.

Alasdair Gray`s 1982 Janine (1984): a postmodernist scottish novel

Alasdair Gray is now an established figure in the Scottish literary scene and has numerous claims to be considered an important voice writing in English. First Lanark: A Life in Four Books (1981) and then 1982 Janine (1984) contributed to the recognition of Gray as one of the founding fathers of the new Scottish writing and as a figure of importance in international contemporary fiction due to his innovative, experimental and postmodernist novels. As the title of this dissertation - “Alasdair Gray’s 1982 Janine (1984): A Postmodernist Scottish Novel” - suggests, it aims at analysing the author’s second novel, 1982 Janine (1984), in a thematic and formal perspective, in order to justify the choice of the terms - Postmodernist and Scottish - to classify this novel. 1982 Janine projects a world through Jock McLeish’s mind and is a powerful stream-of-consciousness narrative. Jock is an alcoholic who lives a personal crisis and, therefore, tries to escape from his depressing reality through sexual fantasies and political diatribes. During a single night in a Scottish hotel room, he drinks and dreams, and spends the whole night alone with his fantasies and fears, his memories and hopes. In Chapter 11, the most daring experimental section of the novel, Jock attempts to commit suicide by taking an overdose of tablets with alcohol but fails. Following this, he decides to review his life and make for a new beginning; the novel thus closing with an optimistic note. Also, the narrative is based on a constant interweaving of sex fantasy with political satire, that is, it is through his protagonist that Gray manages to convey the state of Scotland as well as the concerns and aspirations of the Scottish people and then, proceed to a political and social critique. This dissertation appears structured in three chapters. In Chapter I - “Alasdair Gray: A Postmodernist Scottish Writer” - I present Gray as a powerful postmodernist writer who also sees himself as a Scottish author, and more particularly as a Glaswegian, who concentrates on Scottish subject matter in his literary work. In a first section, I offer a brief survey of the Scottish literary scene from the fourteenth to the twentieth century, in order to understand Gray’s choice of setting and themes and to check his influence or indebtedness to previous Scottish authors. As 1982 Janine is also a good example of selfconscious experimental writing, in a second section, I present various seminal fictional works that introduced and developed experimentalism in British fiction, in order to evaluate the influence of modernist developments in form and technique on recent experimental writing. The third section consists of an introduction to Gray’s work for he is not only a novelist, but also an artist, a playwright, a poet, an activist and a scholar. Chapter II - “Postmodernist Features in 1982 Janine” - aims at listing and examining the postmodernist devices that the novel includes, in what content and form are concerned. On the one hand, the use of a developed type of the modernist stream of consciousness, the presence of a protagonist who feels entrapped in a specific system, the quest for freedom, the incoherence and fragmentation of time, the nonchronological order of the narrative, the blending of fantasy and “reality”, as well as the importance of the Scottish material are definitely current aspects within postmodernist literature that can be found in Gray’s novel. On the other hand, the handling of literary self-conscious devices, such as typographical experimentation, presence of metafiction and intertextuality, and inclusion of an Epilogue, are likewise among recurrent postmodernist features. As the title - “A Narratological Analysis of 1982 Janine” - evidences, Chapter III offers a description of the mechanics of the narrative and its functioning in order to better understand the narrative technique of postmodernist fiction. This study is based primarily on Gérard Genette’s theoretical framework and terminology, presented in Narrative Discourse: An Essay in Method, an analytical tool that allows me to provide a more objective and scientific analysis. Hence, I follow the Genettian division of narrative discourse in Time, Mood and Voice while examining the novel. Finally, I proceed to a description of the intertextual relationships 1982 Janine establishes with other texts.