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Received Nov 30, 2017; Accepted Mar 13, 2018
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1. Introduction
Polylactide micro- and nanoparticles are widely used as drug delivery systems and cell microcarriers [1, 2]. To control the cell attachment, biocompatibility, and drug kinetic release, the particles could be coated with functional polysaccharides during or after a preparation procedure [3–6]. As an alternative, the surface of the particles could be modified using especially synthesized amphiphilic copolymers as functional macromolecular emulsifiers [7]. Another approach to fabrication of core-shell microparticles is based on the application of solid nanoparticles as stabilizing components, that is, preparation via the Pickering emulsions.
The Pickering emulsions, that is, emulsions stabilized by solid nanoparticles instead of molecular emulsifiers, provide a number of benefits, such as high resistance to coalescence and low amount of nanoparticles needed to stabilize an interface [8–10]. The Pickering emulsions were successfully used for preparation of a so-called magnetic polymer microspheres consisted of polystyrene core and Fe3O4 nanoparticle shells [11]. A range of polymeric nanoparticles made of polymer brushes or polymer-grafted particles of various natures could be also used for the Pickering emulsions, which allows one to synthetize new nanocomposites dedicated to specific applications [12–18]. Usage of biocompatible nanoparticles, such as hydroxyapatite, SiO2, proteins, lignin, flavonoids, and various polysaccharides, for the Pickering emulsion stabilization is especially interesting for food or biomedical applications [19–22]. Polysaccharides could be transformed into nanodimensional forms using controlled aggregation of macromolecules [23, 24] or extraction of nanocrystals via hydrolysis of amorphous regions of raw polysaccharides [25–27]. Nanocrystals extracted from cellulose, chitin, and starch are highly crystalline rigid nanoparticles, which morphology and size could significantly vary as a function of raw polysaccharide used [26]. The most widely used cellulose and chitin nanocrystals have a rod-like anisometric morphology with a length and diameter varied from several nanometers to micrometers. They are proposed as reinforcing fillers, templates for preparation of mesoporous materials, for fabrication of semiconductor and smart materials, including mechanically adaptive and self-healing ones. The use of polysaccharide nanocrystals as stabilizing agents in the Pickering emulsions was previously described mainly for food...