Amphiphilic cholesteryl-bearing carboxymethylcellulose derivatives: self-assembly and rheological behaviour in aqueous solution

Abstract

The self-assembly of amphiphilic cholesteryl-bearing carboxymethylcellulose derivatives (CCMCs) from individual molecules to self-aggregates, in addition to their rheological behaviour in aqueous solution were investigated. The conformations of the individual CCMC individual molecules and self-aggregates, and the microstructures of CCMC self-aggregates were characterized using the static and dynamic light scattering analyses, and the steady fluorescence technology. The results showed that the individual CCMC chains became compact, and aqueous NaCl solution changed from an approximate h solvent to a bad one when the number of hydrophobic cholesteryl groups increased. The CCMC self-aggregates exhibited as compact spheres. The microstructural characterization indicated that one CCMC self-aggregate consisted of multiple individual CCMC molecules and hydrophobic microdomains, and multiple cholesteryl groups selfassociated into one hydrophobic microdomain. The atomic force microscopy images of CCMC selfaggregates in phase mode showed that the multiple interior hydrophobic phase separation regions were surrounded by hydrophilic polysaccharide chains, providing an evidence for multiple hydrophobic microdomains in one self-aggregate. The rheological analysis proved that the CCMC self-aggregates were a microgel, in which the associations of cholesteryl groups provided multiple cross-linking points in the polymer network. The microgel solutions displayed a unique thixotropy and a shear thinning behaviour.

Synthesis and characterization of hydrophobic long-chain fatty acylated cellulose and its self-assembled nanoparticles

“…The typical examples include cationic cellulose [5,6], acylated cellulose [7,8], etherificated cellulose [9][10][11][12], hydrophobic cellulose [13][14][15][16][17] as well as amphiphilic cellulose [18][19][20][21][22]. Owing to their non-toxicity, biotolerability, biodegradability, and chemical stability, these cellulose-based polymers can be used as functional biomaterials, bioplastics, and bioenergy to reduce global dependence on the fossil resources.…”

Synthesis and characterization of novel liquid crystalline cholesteryl-modified hydroxypropyl cellulose derivatives

“…Following his research, much of the work in this area focused on the synthesis of cellulose derivatives bearing various hydrophobic residues, such as alkyl groups, bulky phenoxyhydroxypropyl groups, poly(ε-caprolactone) segments, and poly(methyl methacrylate) segments [7][8][9][10]. Bulky cholesteryl-modified amphiphilic chitosan [11][12][13], carboxymethylcellulose [14,15], and sodium alginate [16] derivatives were reported to represent a new kind of biomaterial. According to previous works focusing on the develoment of amphiphilic polysaccharide derivatives, the cholesteryl groups should be considered the bulky hydrophobic segments (rather than the abovementioned hydrophobic residues), because these cholesteryl groups possess better biocompatibility and stronger potential interactions with cholesteryl receptors on the cell surface, as well as a greater ability to drive self-assembly.…”

“…Previous studies in this area [11][12][13][14][15][16] motivated us to synthesize cholesteryl-modified amphiphilic HPC derivatives (CHDs) as drug carriers as a continuation of our research. Thus, in the work described in this paper, we designed and synthesized CHDs with two different functionalizations.…”

The Study of Intermolecular Inclusion in Cellulose Physical Gels

“…Cellulose supramolecular materials are the most promising materials in this field and have been widely studied, especially the self-assembly characteristics of cellulose graft copolymers (Kang et al 2006;Li et al 2008;Liu et al 2012;Shen et al 2006;Vshivkov and Galyas 2011;Yang et al 2008;Yokota et al 2008;Zhao et al 2010). The responsiveness to the external environment Wan et al 2007;Yuan et al 2012) such as temperature (Phan et al 2011) and pH (Dou and Jiang 2007;Wang et al 2011), have led to applications across materials science (smart or adaptive materials, information-recording materials) and medicine (drug release carriers) (Bagheri and Shateri 2012;Dou and Jiang 2007;Tan et al 2010;Wang et al 2011).…”