Temperature-Sensitive, Fluorescent Poly(N-Isopropyl-acrylamide)-Grafted Cellulose Nanocrystals for Drug Release

• Main Authors: Weibing Wu, Jian Li, Wei Liu, Yulin Deng
• Format: Article
• Language: English
• Published: North Carolina State University 2016-07-01
• Series: BioResources
• Subjects: Cellulose nanocrystals; Drug release; Thermo-sensitivity; Poly (N-isopropylacryalamide); Fluorescence
• Online Access: http://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_11_3_7026_Wu_Temperature_Sensitive_Fluorescent_Nanocrystals
• ISSN: 1930-2126; 1930-2126

Cellulose nanocrystals (CNCs) grafted with fluorescent and thermo-responsive poly (N-isopropylacryalamide) (PNIPAM) brushes were prepared for encapsulation and the release of 5-fluorouracil (5-FU). The successful grafting was evidenced by Fourier transform infrared (FTIR) spectroscopy and solid-state 13C nuclear magnetic resonance (13C NMR). Differential scanning calorimetry measurements suggested that the lower critical solution temperature of PNIPAM-grafted CNCs is close 32 °C. During polymerization, tuned fluorescence signatures were obtained by varying the dye dosages. At room temperature, the release amount of the loaded 5-FU was about 42% at a pH of 2.1, while this value approached 60% at a pH of 7.4. Both the cumulative release amount and the release rate were greatly increased when the temperature was raised to 37 °C. The novel PNIPAM-grafted CNCs with both fluorescence and stimuli-sensitive properties possess potential for application in intelligent drug delivery systems.