Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article Citation - WoS: 13Citation - Scopus: 18Stimuli Responsive Polymer-Based Strategies for Polynucleotide Delivery(Cambridge University Press, 2017) Uz, Metin; Alsoy Altınkaya, Sacide; Mallapragada, Surya K.In recent years, stimuli responsive polymer based gene delivery vehicle design for cancer treatment and treatment of other genetic disorders has received extensive attention. Early studies focusing on DNA delivery have been facilitated by functional polymers and this area has seen further growth spurred by recent gene silencing strategies developed for small RNA [i.e., small interfering RNA (siRNA) or micro RNA (miRNA)] delivery. DNA and small RNAs possess analogous properties; however, their explicit differences define the specific challenges associated with the delivery route and the design of functional materials to overcome distinct challenges. Apart from classical gene delivery, the recent advances in genome editing have revealed the necessity of new delivery devices for genome editing tools. A system involving CRISPR (clustered, regularly interspaced, short palindromic repeats) and an endonuclease CRISPR-associated protein 9 (Cas9) coupled with a short, single-guide RNA (sgRNA) has emerged as a promising tool for genome editing along with functional delivery systems. For all these nucleic acid based treatments, the internal or external physiochemical changes in the biological tissue/cells play a major role in the design of stimuli responsive delivery materials for both in vitro and in vivo applications. This review emphasizes the recent advances in the use of pH, temperature, and redox potential-responsive polymers overcoming hurdles for delivery of gene and gene editing tools for both in vitro and in vivo applications. Specifically the chapter focuses on recently proposed delivery strategies, types of delivery systems, and polymer synthesis/modification methods. The recent advances in CRISPR/Cas9-sgRNA technology and delivery are also described in a separate section. The review ends with current clinical trials, concluding remarks, and future perspectives.Article Citation - WoS: 10Citation - Scopus: 10Multi-Zone Drying Schemes for Lowering the Residual Solvent Content During Multi-Component Drying of Semicrystalline Polymers(Taylor and Francis Ltd., 2007) Wong, Sim-Siong; Alsoy Altınkaya, Sacide; Mallapragada, Surya K.The development of a glassy skin in multicomponent semicrystalline polymer systems limits the diffusion of solvents out of the system and increases residual solvent levels. Based on the results of a mathematical model that we had previously developed, we have proposed a multi-zone drying scheme aimed at lowering the residual solvent levels by taking into account the effect of interactions between the various solvents as predicted by the model. This article focuses on the application of this model to develop optimal drying schemes and to verify the effectiveness of these predictions using experimental techniques. The mathematical model developed previously to study the diffusion of multiple solvents and changes in the crystallinity of semicrystalline polymer systems during drying incorporates many features including Vrentas-Duda diffusion theory, solvent-induced crystallization kinetics, as well as glass transition effects and skinning of the film. The multi-zone drying system was developed by varying the drying temperature in each zone as well as changing the partial pressure of individual solvents during the drying process. The effectiveness of the multi-zone drying schemes predicted by the model was validated experimentally using thermogravimetric methods. The polymer-solvent system chosen was a poly(vinyl alcohol)-water-methanol system. Our experimental data suggested that the multi-zone drying schemes were superior to a single-zone drying system through direct comparison. Further examination of the mathematical model yielded individual solvent profiles and these data reaffirmed our conclusions that a multi-zone drying scheme has the ability to reduce the effect of solvent trapping and thus lower the overall residual solvent content.