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

Abstract

Cellulose nanocrystals (CNCs) grafted with fluorescent and thermoresponsive 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 ( 13 C 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 stimulisensitive properties possess potential for application in intelligent drug delivery systems.

Thermally Switchable Liquid Crystals Based on Cellulose Nanocrystals with Patchy Polymer Grafts

“…In aqueous suspensions, such “hairy” nanoparticles exhibited thermo‐reversible aggregation and gelation above the lower critical solution temperature (LCST) of the grafted polymer, resulting in a four‐ to sixfold increase of the hydrodynamic diameter and a corresponding increase of the dynamic storage modulus . Although most of the previous studies have been of fundamental nature, several applications of thermoresponsive‐polymer‐grafted CNCs have been explored, including Pickering emulsions and triggered drug release . Interestingly, however, little attention has been paid to the details of the self‐assembly of such particles, in particular the questions whether or not they form LC phases, and to what extent such LC behavior might be affected by temperature changes around the LCST.…”

Revolutionizing Cancer Treatment: Biopolymer‐Based Aerogels as Smart Platforms for Targeted Drug Delivery

“…[ 75 ] In a different study, Wu and co‐workers developed temperature‐responsive poly ( N ‐isopropylacryalamide)‐cellulose nanocrystals brushes via activators generated by electron transfer for atom transfer radical polymerization, aiming at delivering 5‐fluracil. [ 76 ] The grafted biopolymers exhibited stabilized dispersion in water attributed to the hydrophilic cellulose backbone and poly ( N ‐isopropylacryalamide) side chains. Below the lower critical solution temperature, the hydrogen bonds between the grafted cellulose nanocrystals and 5‐fluracil effectively retained the drug molecules…”

“…Consequently, an elevation in the release of the drug was observed as the temperature rose (from 25 to 37 °C) due to the weakened hydrogen bonding interactions between cellulose nanocrystals grafted with 5‐fluorouracil, as indicated by. [ 76 ] This thermally‐triggered drug release pattern exhibited by the cellulose nanocrystals grafted with poly( N ‐isopropylacrylamide) underscores its potential as a promising contender for temperature‐responsive drug delivery systems. To augment the moisture absorption capacity, Matsumoto and co‐workers developed thermo‐responsive hydrogels and aerogels utilizing an interpenetrating polymer network gel, comprising sodium alginate chains for hydrophilicity and poly( N ‐isopropylacrylamide) chains for thermo‐responsiveness ( Figure ).…”

Synthesis of 2-hydroxy-3-isopropoxypropyl guar gum and its thermo-responsive property for controlled release

“…Stimuli-responsive polymeric materials are a new class of materials that can change their physicochemical properties in response to external environmental factors, such as temperature, pH, ionic strength, and light intensity (Wu et al 2016;Alejo et al 2019;Yuba 2020). In recent years, stimuli-responsive polymers that have amphiphilic structures have received widespread attention in the field of biological medicine for two main reasons.…”