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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Synthesis and characterization of novel temperature-responsive dendritic PEG-PDLLA star polymers for drug delivery

Kailasan, Arunvel 25 November 2008 (has links)
This study describes a novel thermoresponsive dendritic polyethylene glycol-poly(D, L-lactide) (PEG-PDLLA) core-shell nanoparticle with potential for drug delivery and controlled release. A series of dendritic PEG-PDLLA nanoparticles were synthesized through conjugation of PEG to Starburst™ polyamidoamine (PAMAM) dendrimer G3.0 and subsequent ring-opening polymerization of DLLA, in which PEG chain length (i.e., MW=1500, 6000 or 12000 Dalton) was varied; however, the feeding molar ratio of DLLA monomers to the overall PEG repeat units on the dendrimer surface was kept at 1:1. Linear PEG-PDLLA copolymers were also syntheiszed under the same condition and used as control. According to our results, dendritic PEG-PDLLA in aqueous phase could self-assemble into spherical aggregates and the size of spherical aggregates increased with PEG chain length increase. Further, spherical aggregates made of dendritic PEG-PDLLA exhibited magnified temperature-dependence in terms of solubility change and dimension expansion as compared to linear PEG-PDLLA. The most significant size expansion was observed in particles made of dendritic PEG (12000)-PDLLA, which was twice as much as that of particles made of linear PEG (12000)-PDLLA. Water insoluble antitumor drug camptothecin (CPT) was used as a model drug for encapsulation and release studies. Spherical aggregates encapsulated more CPT when dendritic PEG-PDLLA had longer PEG-PDLLA chain and/or when temperature was elevated to body temperature. This study demonstrated that nanoscale clustering PEG-PDLLA through dendrimers magnified the thermo-sensitivity of PEG-PDLLA. Successful development of such a new particulate system made of dendritic PEG-PDLLA with an expandable dimension in response to temperature change generated a new direction for designing stimuli-responsive materials.
2

Studium vlivu kvantových teček na biologické systémy a jejich komponenty / Study of influence of quantum dots to biological systmes and their components

Koudelková, Zuzana January 2015 (has links)
The aim of this thesis is to summarize the available evidence about quantum dots and their effects on living systems. The text describes methods for the preparation of quantum dots with respect to their characteristics (size, fluorescence wavelength) and methods of quantum dots bio-functionalization of biomolecules. In living organisms is a large number of proteins, because these are considered as one of the main components of the interaction of organisms. Therefore, the work also provides basic information about proteins. Finally, there are described various methods by which the quantum dots may be characterized mainly by differential pulse voltammetry measurement zeta potential and fluorescence measurement. The main objective of this work is to propose models of different environments in which will be degradation of quantum dots with regard to the evaluation of acquired kinetic parameters for predicting the stability of individual quantum dots.

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