title: Refined control of thermoresponsive swelling/deswelling and drug release properties of poly(N-isopropylacrylamide) hydrogels using hydrophilic polymer crosslinkers.
abstract: Thermoresponsive poly(N-isopropylacrylamide) (PNIPAm)-based hydrogels are widely investigated for their ability to alter their physical properties (e.g. dimensions, swelling/deswelling) in response to change in temperature. Despite extensive research efforts, it is still challenging to control various aspects of thermoresponsive physical properties of PNIPAm hydrogels in an efficient and comprehensive manner using conventional small molecular crosslinkers due to their limited solubility and functional groups. Herein, thermoresponsive swelling/deswelling behavior of PNIPAm hydrogels is tuned in a wide range by hydrophilic polymeric crosslinkers with varying chain lengths. The concentration and molecular weight of the poly(ethylene glycol) (PEG) crosslinker are varied to control the swelling/deswelling behavior, drug release, and lower critical solution temperature (LCST) of PNIPAm-PEG hydrogels. Compared with PNIPAm hydrogels crosslinked with a conventional small molecular crosslinker, N,N'-methylenebisacrylamide, greater degree and range of thermoresponsive swelling/deswelling as well as tunable LCST are demonstrated for PNIPAm-PEG hydrogels. In addition, more swelling-controlled PNIPAm-PEG hydrogels displayed more sustained and variable thermoresponsive drug release based on their crosslinking density, by modulating the hydrophobic transition of PNIPAm chains with hydrophilic PEG chains. In sum, various thermoresponsive properties of PNIPAm hydrogels could be controlled by hydrophilic polymeric crosslinkers, and this strategy could be applied to various hydrogel systems to control their physical properties for biomedical applications.
authors: a School of Materials Science and Engineering , Ulsan National Institute of Science and Technology , Ulsan , South Korea.
authors: Suntae
authors: S
authors: Kim
authors: b School of Life Sciences , Ulsan National Institute of Science and Technology , Ulsan , South Korea.
authors: Kangseok
authors: K
authors: Lee
authors: a School of Materials Science and Engineering , Ulsan National Institute of Science and Technology , Ulsan , South Korea.|b School of Life Sciences , Ulsan National Institute of Science and Technology , Ulsan , South Korea.
authors: Chaenyung
authors: C
authors: Cha
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D004337:Drug Carriers / Q000737:chemistry*; D065546:Drug Liberation; D020100:Hydrogels / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D055595:Mechanical Phenomena; D008970:Molecular Weight; D011092:Polyethylene Glycols / Q000737:chemistry; D012995:Solubility; D013696:Temperature
chemical_list: D000180:Acrylic Resins; D004337:Drug Carriers; D020100:Hydrogels; C052970:poly-N-isopropylacrylamide; D011092:Polyethylene Glycols
keywords: Thermoresponsive; drug release; hydrogel; poly(N-isopropylacrylamide) (PNIPAm); poly(ethylene glycol) (PEG) crosslinker