Design of intelligent nanoparticles for use in controlled release

Bayyurt, Banu
The aim of this project was to design an intelligent controlled release system based on thermoresponsive nanoparticles for cancer therapy and to evaluate the efficiencies of these systems with in vitro cell culture. Poly(Nisopropylacrylamide), an important thermoresponsive polymer, was selected for this study to prepare the responsive nanoparticles. This polymer has an lower critical solution temperature (LCST) of 32 oC, below which it is hydrophilic and above this temperature, it shows hydrophobic behavior. Controlling drug release with this property was the objective of this study. Nanoparticles were prepared by nanoprecipitation method. By using different solvent:non-solvent ratios and polymer concentrations, different samples were prepared. The particle size was decreased when solvent:non-solvent ratio was increased and polymer concentration was decreased. This was found to be related with the solution viscosity. Nanoparticles prepared from polymers prepared with different initiatoraccelarator amounts had significantly different sizes and release rates, and additionally the size of particles prepared from polymers with various crosslinker amounts were decreased with increased croslinker amount. In situ release experiments were performed both below and above polymer‘s LCST degree. Uncrosslinked nanoparticles demonstrated higher release rate of Celecoxib above LCST. However, there was no significant difference with the crosslinked nanoparticles. Crosslinked and uncrosslinked nanoparticles were tested on Saos-2 cells to assess their toxicity. Both Celecoxib loaded and free crosslinked particles were found to be cytotoxic. Uncrosslinked nanoparticles showed an increased toxicity upon loading with the bioactive agent, Celecoxib. In conclusion, uncrosslinked particles would be a proper drug carrier for cancer therapy with enhanced drug loading.


Development of PCR methods for detection and quantification of genetically modified maize
Jabbari Farhoud, Houman; Gültekin, Güzin Candan; Department of Biotechnology (2010)
This study describes development of methods for screening, identification and quantification of genetic modifications in maize samples. Totally 88 maize samples were collected randomly throughout Turkey in three years from 2006 to 2008 and were analyzed. Two maize samples that were detected as GM positive in previous studies were selected as positive controls. Following the DNA extraction by manual CTAB method, conventional PCR methods were employed for screening of genetic modifications in samples by detec...
Recombinant therapeutic protease production by Bacillus sp.
Korkmaz, Nuriye; Çalık, Pınar; Department of Chemical Engineering (2007)
The first aim of this study is the development of extracellular recombinant therapeutic protease streptokinase producing Bacillus sp., and the second aim is to determine fermentation characteristics for streptokinase production. In this context, the signal (pre-) DNA sequence of B.licheniformis (DSM1969) extracellular serine alkaline protease enzyme gene (subC: Acc. No. X03341) was ligated to 5’ end of the streptokinase gene (skc: Acc. No. S46536) by SOE (Gene Splicing by Overlap Extension) method through P...
Comparison of benzaldehyde lyase production capacity in recombinant Escherichia coli and recombinant Bacillus species
Kaya, Hande; Çalık, Pınar; Department of Chemical Engineering (2006)
In this study, the benzaldehyde lyase (BAL, EC production in E. coli BL21 (DE3) pLySs as intracellular and in Bacillus species as extracellular were investigated, and comparison of the production capacity of the enzyme in the developed recombinant microorganisms were compared. For this purpose, firstly, PCR amplified bal gene was cloned into pRSETA vector which is under the control of strong T7 promoter and expressed in E. coli BL21 (DE3) pLysS strain. With developed recombinant E. coli BL21 (DE3)...
Expression system for synthesis and purification of recombinant human growth hormone in Pichia pastoris and structural analysis by MALDI-ToF mass spectrometry
Çalık, Pınar; Celik, Eda; Halloran, S. Mitchell; Calik, Guezide; Ozdamar, Tuncer H. (Wiley, 2008-01-01)
An expression system in Pichia pastoris for the production and purification of recombinant human growth hormone (rHGH) was designed and implemented. hGH cDNA sequence was cloned into pPICZ alpha A vector under the control of AOX1 promoter, which included a polyhistidine-tag on the amino terminal end to enable affinity purification and a target site for Factor Xa protease such that protease cleavage in vitro would produce rhGH without any non-native Nand C-termini. Analyses of the affinity-purified rhGH prod...
Design of a core-shell type immuno-magnetic separation system and multiplex PCR for rapid detection of pathogens from food samples
Ozalp, V. Cengiz; BAYRAMOĞLU, GÜLAY; ARICA, MEHMET YAKUP; Öktem, Hüseyin Avni (Springer Science and Business Media LLC, 2013-11-01)
We report an immuno-magnetic separation system developed by the immobilization of pathogen-specific antibodies on the core-shell magnetic beads. The magnetic beads were grafted with glycidylmethacrylate (GMA) using surface-initiated atom transfer radical polymerization (SI-ATRP). For immuno-magnetic separation (IMS) of target bacterial cells from others, antibodies for Escherichia coli and Salmonella enterica serovar Typhimurium cells were immobilized on the magnetic beads via glutaraldehyde coupling reacti...
Citation Formats
B. Bayyurt, “Design of intelligent nanoparticles for use in controlled release,” M.S. - Master of Science, Middle East Technical University, 2009.