title: Tuning the sphere-to-rod transition in the self-assembly of thermoresponsive polymer hybrids.
abstract: Nano-scale drug delivery systems have undergone extensive development, and control of size and structure is critical for regulation of their biological responses and therapeutic efficacy. Amphiphilic polymers that form self-assembled structures in aqueous media have been investigated and used for the diagnosis and therapy of various diseases, including cancer. Here, we report the design and fabrication of thermoresponsive polymeric micelles from alginate conjugated with poly(N-isopropylacrylamide) (PNIPAAm). Alginate-PNIPAAm hybrids formed self-aggregated structures in response to temperature changes near body temperature. A structural transition from micellar spheres to rods of alginate-PNIPAAm hybrids was observed depending on the molecular weight of PNIPAAm and the polymer concentration. Additionally, hydrogels with nanofibrous structures were formed by simply increasing the polymer concentration. This approach to controlling the structure of polymer micelles from nanoparticles to fibrous hydrogels may be useful in applications in drug delivery and tissue engineering.
authors.affiliation: Department of Bioengineering, Hanyang University, Seoul 133-791, Republic of Korea; Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea.
authors.forename: Jangwook
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Bioengineering, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Honghyun
authors.initials: H
authors.lastname: Park
authors.affiliation: Department of Bioengineering, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Eun Ju
authors.initials: EJ
authors.lastname: Jeong
authors.affiliation: Department of Organic Materials and Fiber Engineering, Soongsil University, Seoul 156-743, Republic of Korea.
authors.forename: Young-Je
authors.initials: YJ
authors.lastname: Kwark
authors.affiliation: Department of Bioengineering, Hanyang University, Seoul 133-791, Republic of Korea; Center for Theragnosis, Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 136-791, Republic of Korea. Electronic address: leeky@hanyang.ac.kr.
authors.forename: Kuen Yong
authors.initials: KY
authors.lastname: Lee
mesh_terms: D008823:Micelles; D011108:Polymers / Q000737:chemistry*; D013696:Temperature
chemical_list: D008823:Micelles; D011108:Polymers
keywords: Alginate; Poly(N-isopropylacrylamide); Rod; Self-assembly; Sphere; Thermoreversible