Το παρόν πόνημα αναπτύχθηκε προκειμένου να υποδειχθεί η σύνθεση και η μελέτη πολυλειτουργικών μαγνητικών νανοσωματιδίων τα οποία φέρουν μόρια της δραστικής φαρμακευτικής ουσίας Πακλιταξέλη (Ταξόλη - ΤΑXOLTM), ως εναλλακτικός τρόπος χορήγησης με υψηλή ακρίβεια στο στόχο, στο χρόνο και στην ποσότητα που απαιτείται για την αντιμετώπιση του καρκίνου του μαζικού αδένα, εκμεταλλευόμενοι τις ιδιότητες που περιλαμβάνουν το μικρό τους μέγεθος, στην κλίμακα του νανομέτρου,το μεγάλο εμβαδόν της επιφανείας τους, η δυνατότητα διαχείρισής τους από απόσταση και οι σχεδόν μηδενικές παρενέργειες.Τα σωματίδια ενίονται στον οργανισμό και μέσω της συστηματικής κυκλοφορίας κατευθύνονται με την βοήθεια ενός εξωτερικού μαγνητικού πεδίου στο όργανο-στόχο (στοχευμένη θεραπεία). Η Πακλιταξέλη αποτελεί ευρέως διαδεδομένο αντικαρκινικό παράγοντα, με σημαντικές ωστόσο παρενέργειες λόγω χαμηλής εκλεκτικότητας. Στην παρούσα μελέτη παρασκευάστηκαν μαγνητικά νανοσωματίδια οξειδίου του σιδήρου βασισμένα σε πολυμερικά μικύλλια PLA-PEG, τα οποία ενθυλάκωσαν την δραστική ουσία, προκειμένου να επιτευχθεί ο σκοπός παρατεταμένης παραμονής και στοχευμένης χορήγησης. Η διαδικασία του πειράματος περιλαμβάνει την σύνθεση παραμαγνητικών αλλά και μη μαγνητικών νανοφορέων, την ανάλυση των φυσικοχημικών ιδιοτήτων τους με τεχνικές σκέδασης του φωτός και ηλεκτροφόρησης και τον έλεγχο της σταθερότητάς τους σε διαφορετικές συνθήκες. Επιπροσθέτως, εξετάστηκε η δομή τους με ηλεκτρονική μικροσκοπία διαπερατότητας (TEM). Η μελέτη περιλαμβάνει επίσης μελέτες αποδέσμευσης της δραστικής ουσίας από τα νανοσωμάτια, αποβλέποντας στην απόδειξη της παρατεταμένης απελευθέρωσης, ενώ εν συνεχεία εξετάστηκε και η επίδραση εξωτερικού εναλλασσόμενου μαγνητικού πεδίου στο ρυθμό αποδέσμευσης της πακλιταξέλης. Παράλληλα, μελετήθηκε η τοξικότητα όλων των μαγνητικών νανοσωματιδίων που έφεραν πακλιταξέλη, με στόχο τον προσδιορισμό της επίδρασης στα επιθηλιακά νεοπλασματικά κύτταρα του μαστού. Τα αποτελέσματα της μελέτης οδήγησαν στην εξαγωγή ασφαλών συμπερασμάτων για τα μαγνητικά νανοσυστήματα πακλιταξέλης όσον αφορά τις ικανοποιητικές ιδιότητες κολλοειδούς σταθερότητας, ενθυλάκωσης και αποδέσμευσης της δραστικής ουσίας, επιτρέποντας τον σχεδιασμό και την πραγματοποίηση διερευνητικών ενεργειών για την πιθανή χρήση αυτών σε περαιτέρω κλινικές περιπτώσεις. / The aim of the current study is the synthesis and characterisation of multifunctional magnetic nanoparticles of the drug agent Paclitaxel (Taxol)in order to determine their use for the targeted treatment of cancer.This will be an alternative method of administration, which results in high accuracy on the target, boh in time and in the amount of drug required for the treatment of mammary cancer. We exploit tsome of the interesting properties of the nanoparticles for this purpose, such as their small size on the nanometer scale, the large area of their surface, their management ability to remotely and their virtually zero side effects. The particles are injected in the body via the systemic circulation driven by means of an external magnetic field to the target organ (targeted therapy). Paclitaxel is a widely used anticancer agent, with significant side effects, however, due to low selectivity. In the present study were prepared magnetic iron oxide nanoparticles based on polymeric micelles of PLA-mPEG, which encapsulate the active substance, in order to achieve the purpose of sustained residence and targeted delivery. The procedure of the experiment includes the synthesis of paramagnetic and non-magnetic nanoparticles, analysis of their physicochemical properties by techniques of light scattering and electrophoresis and examination of their stability in different conditions. Furthermore, their structure was examined by transmission electron microscopy. The study also includes release studies of the active substance of the nanoparticles, aiming to demonstrate the sustained release, and subsequently theexaminationof the effect of an external alternating magnetic field in the release rate of paclitaxel. We also studied the toxicity of all magnetic nanoparticles carrying paclitaxel to identify the effect on epithelial neoplastic breast cells. The results of the study led to reliable conclusions about magnetic nanosystems of Paclitaxel regarding satisfactory colloidal stability properties, encapsulation and release of the active substance, allowing the design and implementation of further exploratory actions for possible use in further clinical cases.

No description available.

Micromachined needles have been shown to successfully transport biological molecules into the body with minimal invasiveness and pain, following the insertion of needles into the skin. The aim of this research is to demonstrate that micromachined hollow polymer needle arrays fabricated using UV lithography into micromolds, a potential batch-manufacturable process, can exhibit comparable insertion and injection performance to conventional hypodermic needles for drug delivery into skin. A dual-exposure-and-single-development process flow is proposed for the above-mentioned UV lithography into micromolds approach to construct a pyramidal-tip hollow microneedle array with an integral baseplate and fluidic manifold. The developed process ultimately resulted in the ability to fabricate a 10×10 array of hollow SU-8 microneedles measuring 825 μm in height, 400 μm in width, and possessing a lumen of 120 μm in diameter. The tip diameter of the microneedles ranges from 15 μm to 25 μm. The insertion force of single needles characterized using excised porcine skin as a substrate is 2.4±1.2 N. Nevertheless, the high insertion force of 2.4 N per needle may cause a significant concern when a large number of needles are required to insert into skin for drug delivery. Conventional hypodermic needles have two key structural characteristics: a sharp beveled tip and a large side-terminated lumen. Integration of these two key characteristics of hypodermic needles into microneedle design can potentially enhance microneedle performance. To reduce the insertion force and to incorporate the two key characteristics of hypodermic needles into the design of microneedles, a new needle tip design, namely the hypodermic-needle-like design, is presented. A 6×6 array of hypodermic-needle-like microneedles of 1 mm in height, approximate 350 μm in width, and with a lumen of 150 μm in diameter is demonstrated with successful insertion of the needle array into skin and an 85% lumen openness yield. The insertion force is significantly reduced by an order of magnitude with the new needle tip design and is 0.275±0.113 N per needle, comparable to that of hypodermic needles, i.e., 0.284±0.059 N. The hypodermic-needle-like microneedles exhibit a margin of safety of 180 for successful needle insertion into skin prior to needle fracture. A successful manual fluid injection into skin using single microneedle is demonstrated. The micromachined hypodermic-needle-like polymer needle arrays presented in this dissertation are fabricated using UV lithography into micromolds, a potentially batch-manufacturable process, and exhibit comparable insertion performance to conventional hypodermic needles. Injection capability into skin is also demonstrated with a hypodermic-needle-like microneedle, illustrating the utility of these devices.

Since its discovery 15 years ago there has been an explosion of research in the field of DNA immunisation. Unfortunately despite early promises that DNA immunisation had the potential to cure almost any infectious disease, autoimmune disease or even cancer, progress towards clinical trials has been slow. This has been due in part to the huge range of permutations possible in delivering the DNA. One approach is to deliver the DNA by gene gun. Gene gun delivery is a very efficient way of transfecting cells however also has a number of possible disadvantages. These drawbacks include a weak immunogenicity in larger animals as well as the tendency to bias towards the development of a strong type 2 response. In an effort to enhance antigen-specific immune responses and counter the type 2 polarisation of gene gun delivery, a series of DNA vaccines were created where the extracellular portion of the hemagglutinin (HA) gene from influenza A/PR8/34 virus was genetically fused the type 1 cytokines IFNγ, IL-12 and IL-23. Interleukin-23 has been recently discovered and even though both IL-12 and IL-23 contain the p40 subunit they seem to have dissimilar functions. The vaccine constructs were first tested in cellular assays in vitro to ensure correct production and biological activity of the attached cytokines. They were then delivered in various combinations to groups of BALB/c mice to test development of immune responses and the effect of different delivery regimes. Finally mice were immunised then challenged with live influenza virus to determine the different DNA vaccines� protective efficacy. DNA vaccines containing the HA gene alone (pHA) or fused to IFNγ (pIFNγHA), IL-12 (pIL-12HA) or IL-23 (pIL-23HA) were successfully constructed. The fusion of the HA gene to the genes for IFNγ, IL-12 or IL-23 did not significantly disturb the structure of the antigen or prevent the biological actions of the cytokines. Mice immunised three times with pHA had high titres of serum IgG1 antibody and their splenocytes produced approximately equal amounts of IFNγ and IL-5. Co-delivery of IFNγ was unable to alter immune responses regardless of whether it was delivered at the first, last or during all immunisations. Surprisingly co-delivery of IL-12 acted to suppress both antibody and cellular immune responses, possibly through an IFNγ/nitric oxide feedback loop. On the other hand co-delivery of IL-23 tended to enhanced immune responses and, while it did not significantly alter the type 1 to type 2 balance, it was able to increase the ability of mice to clear live influenza virus from their lungs when they were challenged 26 weeks after immunisation. This protection was associated with increased levels of neutralising antibody in the serum of pIL-23HA immunised mice. This research has illuminated several of the pitfalls in the development of DNA vaccines and the use of cytokine as adjuvants. However it has also broadened our understanding of IL-23 and implies that IL-23 could be effectively used to increase the development of longterm immunity after immunisation.

Purpose: The aim of this thesis was to investigate a suitable formulation for the topical delivery of growth factors to chronic wounds, and then to determine the concentrations reached within an animal wound model. A secondary aim was to determine if the chosen growth factor was present at levels able to stimulate the production of other cytokines, specifically IL-1β and MCP-1. Methods: An in vitro testing apparatus was designed and made and the release of model actives [bromophenol blue (BPB) and horseradish peroxidase (HRP)] from gels and films of hydroxylpropylmethylcellulose (HPMC) (E4M CR, K4M CR and E10M CR) was determined. In this study, Fibroblast Growth Factor -2 (FGF-2) (0.3 [mu]g) was incorporated into three formulations (solution, gel and dried gel film on Melolin[TM] backing) and together with a control formulation were administered to punch biopsy wounds in rats. The in vivo release was followed over three time periods (two, five and eight hours) and the amount of FGF-2 at various wound depths was quantified by ELISA. Two biological markers IL-1β and MCP-1 were quantified using ELISA. The FGF-2 was additionally tagged with a fluorescent dye so that visualisation of the penetration could be obtained via confocal microsopy. Results: For the HPMC gels, the more viscous gel (E10M) provided a greater diffusional barrier and slowed the release of BPB (12 � 3.5 [mu]g/min compared with 16 � 1.7 [mu]g/min and 18 � 1.4 [mu]g/min for K4M and E4M respectively). However, when HPMC was formulated as a dried film a burst release was seen and release of BPB was slowest from the more rapidly hydrating K4M. With the larger model active HRP, there was a slower diffusion through the gel barrier formed upon film hydration, such that time of 100% release was up to 300 minutes compared to approximately 60 minutes for BPB. When the film was dried onto a supportive backing, the initial burst release was minimised as the film did not break apart on contact with the wound, and hence film integrity was maintained and release prolonged. The in vivo studies showed that, two hours after application, the highest concentration of FGF-2 was seen in the surface granulation tissue of rats that received the solution formulation (2280 � 790 pg/g). The concentration decreased with increasing tissue depth but was significantly greater than the saline control in the surface granulation and subcutaneous fat layers (p<0.05). Tissue concentrations following application of the gel and film formulations were only marginally greater than control in the surface granulation layer. After eight hours, rats that received the solution retained elevated surface tissue concentrations (surface granulation and subcutaneous fat) of FGF-2. Repeated measures ANOVA using a general linear model showed statistically significant differences in the mean FGF-2 level with respect to formulation and length of time of application of the formulation (p<0.05). In terms of other cytokines, there was a release of both IL-1β and MCP-1 in all groups, immediately post-wounding, probably in response to cellular damage. After eight hours, the film formulation appeared to elevate IL-1β levels which may be useful to drive wound healing. Confocal microscopy images showed diffuse distribution of FGF-2 eight hours after application of the solution formulation after eight hours and that with the gel formulation FGF-2 initially aggregated at the wound surface. Conclusion: In vitro experiments investigating the effect of hydration rate and viscosity of HPLC polymers allowed a formulation to be chosen for further in vivo study. Elevated FGF-2 could be measured in superficial wound tissues up to eight hours after application of a solution. However, application of a comparable amount of FGF-2 in HPMC gels or films did not produce appreciable elevations in FGF-2 in wound tissues, although confocal microscopy indicated the penetration of FGF-2 into the wound for up to eight hours.

Thesis (Ph. D.)--University of Wisconsin--Madison, 2006. / Includes bibliographical references. Also available on the Internet.

Thesis (Ph.D.)--University of Wisconsin--Madison, 2006. / Includes bibliographical references. Also available on the Internet.

Dissertation (Ph.D.)--Auburn University, 2006. / Abstract. Vita. Includes bibliographic references.

Diss. (sammanfattning) Uppsala : Univ., 2004. / Härtill 4 uppsatser.

Diss. (sammanfattning) Uppsala : Univ., 2001. / Härtill 6 uppsatser.