Synthesis and characterization of thermosensitive nanoparticles based on PNIPAAm core and chitosan shell structure

Abstract

Noble thermosensitive nanoparticles, based on a PNIPAAm-co-AA core and a chitosan shell structure, were designed and synthesized for the controlled release of the loaded drug. PNIPAAm nanoparticles containing a carboxylic group on their surface were synthesized using emulsion polymerization. The carboxylic groups were conjugated with the amino group of a low molecular weight, water soluble chitosan. The particle size of the synthesized nanoparticles was decreased from 380 to 25 nm as the temperature of the dispersed medium was increased. Chitosan-conjugated nanoparticles with 2~5 wt% MBA, a crosslinking monomer, induced a stable aqueous dispersion at a concentration of 1 mg/1 mL. The chitosan-conjugated nanoparticles showed thermosensitive behaviors such as LCST and size shrinkage that were affected by the PNIPAAm core and induced some particle aggregation around LCST, which was not shown in the NIPAAm-co-AA nanoparticles. These chitosan-conjugated nanoparticles are also expected to be more biocompatible than the PNIPAAm core itself through the chitosan shell structures.

Surface modification of montmorillonite (MMT) using column chromatography technique and its application in silicone rubber nanocomposites

“…27,28 The influence of organomodified clay towards the various properties of different polymers has been studied but least on rubber-clay composites. 10,29,30 The improvement greatly depends on the distribution of the layers of the silicates in the polymer matrix. If the layers are well ordered and the polymer chains are inserted into the gallery space of the silicate there is an intercalated structure.…”

“…[1][2][3][4][5][6][7][8][9][10][11] This is mainly attributed to the nanoscale dimension of silicate layers dispersed in the polymer matrix, which causes a strong interfacial interaction between silicate layers and polymer chains leading to a drastic effect on thermal stability, mechanical, physical, barrier and optical properties with impressive fire resistance properties as compared to pristine polymers. [12][13][14][15][16][17][18] Clay minerals have been extensively used as a reinforcing agent because of their low cost and easy availability 14,19,20 compared to other layered materials.…”

Novel Synthesis Pathways for PNIPAAm-Based Hydrogels and Their Application in Thermosensitive Textiles

“…Afterwards, semitelechelic PNIPAAm was grafted on chitosan film having amino groups (surface graft) or dissolved together with chitosan in acetic acid to form bulk graft [24]. Similar approach for synthesis of thermosensitive nanoparticles based on PNIPAAm core and chitosan shell was applied by Jung et al [25]. PNIPAAm core nanoparticles containing carboxylic groups on their surface were synthesized by emulsion copolymerization between NIPAAm and acrylic acid (AAc) as a copolymer (PNIPAAm-co-AAc core) using MBAAm as a cross-linker.…”

Synthesis of poly(N-isopropylacrylamide)/poly(ethyl-2-cyanoacrylate) composite hollow particles

“…19 Herein, we aimed to fabricate monodisperse composite hollow particles of poly(N-isopropylacrylamide)/poly(ethyl-2-cyanoacrylate) (namely, poly(NIPAAm)/ poly(E2CA)) by using SPG emulsification, ionic, and photo-polymerization techniques. Poly(NIPAAm) is well known biocompatible polymer exhibiting volume phase transition temperature (VPTT) near lower critical solution temperature (LCST) around 35 o C. 3,20,21 Poly(E2CA), known as one of 'instant' adhesive family, is both biocompatible and biodegradable. In this work, we found that shell morphology of the composite hollow particles was changed from semi-interpenetrating network (semi-IPN) to double shell structure depending on the mass ratio of NIPAAm and E2CA monomers.…”