Research Article Temperature Driven Transformation in Dextran-Graft- PNIPAM/Embedded Silver Nanoparticle Hybrid System V. Chumachenko, 1 N. Kutsevol , 1 Iu Harahuts, 1 D. Soloviov, 2 L. Bulavin, 2 O. Yeshchenko, 2 A. Naumenko , 2 O. Nadtoka , 1 and A. Marinin 3 1 Faculty of Chemistry, Taras Shevchenko National University of Kyiv, 01601 64/13 Volodymyrska St., Kyiv, Ukraine 2 Faculty of Physics, Taras Shevchenko National University of Kyiv, 01601 64/13 Volodymyrska St., Kyiv, Ukraine 3 Problem Research Laboratory, National University of Food Technology, Volodymyrska Str. 68, 01601 Kyiv, Ukraine Correspondence should be addressed to A. Naumenko; a_naumenko@univ.kiev.ua Received 7 February 2019; Revised 17 April 2019; Accepted 21 May 2019; Published 12 June 2019 Guest Editor: Marco Caniato Copyright © 2019 V. Chumachenko et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. During the last decade, stimuli-responsible polymers based on poly(N-isopropylacrylamide) having conformational transition in the range of physiological temperature have been discussed as novel drug delivery nanosystems. A star-like copolymer with a dextran core and grafted poly(N-isopropylacrylamide) arms (D-g-PNIPAM) was synthesized, characterized, and used as a matrix for silver sol preparation. The comparative study of the behavior of individual D-g-PNIPAM and the nanohybrid system D-g-PNIPAM/silver nanoparticles has been done in the temperature range near the lower critical solution temperature (LCST). The methods of Dynamic Light Scattering, small angle X-ray scattering, and UV-VIS absorption spectroscopy have been used. The existence of single nanoparticles and aggregated nanoparticles located in a limited polymer macromolecular volume was established. The increase of the temperature leads to slight aggregation of the silver nanoparticles at the LCST transition. Single nanoparticles do not aggregate with the temperature increase. The thermally induced collapse of end-grafted poly(N-isopropylacrylamide) chains above the LCST do not affect significantly the size characteristics of silver nanoparticles incorporated into the polymer matrix. 1. Introduction The growing progress in nanotechnology and the life sciences demonstrates an urgent need for novel advanced hybrid materials composed of biocompatible polymers and inor- ganic components [1–3]. The development of nanometer- sized materials that can perform a desired action upon a local or external stimulus is one major goal of bionano- technology [4]. Temperature-sensitive polymers allow the creation of locally controlled actuators that can have various applications [4–7]. In recent years, the poly(N-isopropylacrylamide) (PNIPAM) polymer became a subject of study as a promising base for fabrication of nanocomposites for biomedical appli- cation [8–10]. Linear PNIPAM is a thermoresponsive poly- mer widely known for its lower critical solution temperature (LCST) phenomenon at 32 ° C in aqueous solutions. PNIPAM has coil-to-globule transition at LCST and applies a pore opening and closing mechanism to the porous particles [11]. This mechanism helps in the temperature-triggered release of the loaded molecules into a polymer matrix. The transition temperature for linear PNIPAM is very close to the human skin; thus, this polymer can be applied for photodynamic anti- cancer therapy [12, 13]. For a larger window of applications, especially in the field of nanotechnology as drug delivery sys- tems, LCST should be shifted to higher temperatures. It was shown that the branched structure of PNIPAM-containing polymers opened the possibility to tune the LCST [14, 15]. Also, it was established that the star-like copolymer dextran- graft-PNIPAM can be used as a universal platform for drug delivery, namely, dextran-PNIPAM+doxorubicin nanoparti- cles have huge potential as novel anticancer agents [16]. Hindawi International Journal of Polymer Science Volume 2019, Article ID 3765614, 7 pages https://doi.org/10.1155/2019/3765614