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Alginate-galactosylated chitosan/polylysine (AGCP) microcapsules with excellent stability and high permeability were developed and employed in primary hepatocyte applications. The galactosylated chitosan (GC), synthesized via the covalent coupling of lactobionic acid (LA) with low molecular weight and water-soluble chitosan (CS), was ingeniously introduced into the core of alginate microcapsules by regulating the pH of gelling bath. The internal GC of the microcapsules simultaneously provided a large number of binding sites for the hepatocytes and further promoted the hepatocyte-matrix interactions via the recognition of asialoglycoprotein receptors (ASGPRs) on the hepatocyte surface, and afforded the AGCP microcapsules an excellent stability via the electrostatic interactions with alginate. As a consequence, primary hepatocytes in AGCP microcapsules demonstrated enhanced viability, urea synthesis, albumin secretion, and P-450 enzyme activity, showing great prospects for hepatocyte applications in microcapsule system., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In this study, an improved indirect cell coculture system was constructed by using a polyelectrolyte complex membrane generated by alginate (A) and chitosan (C). Methodologies of characterizing thickness and permeability of flat AC membrane were first established due to the importance of these two parameters in determining intercellular distance and degree of contact between cocultured cells. Compared to reaction time, both alginate concentration and molecular weight (Mw) of chitosan play more dominant roles in determining the membrane thickness and diffusion coefficients. Moreover, cells in the alginate gel and on the AC membrane could maintain high cell viability. Thus, an improved indirect cell coculture system constructed by flat AC membrane was fabricated and characterized, which provides a robust tool to study the effect of intercellular distance and degree of contact between cocultured cells on cell-cell interactions. [ABSTRACT FROM AUTHOR]

Small-interfering RNA (siRNA)-mediated gene silencing with the aid of chitosan (CS)-based carriers has shown efficient and reliable outcome in vitro , but the gene silencing efficiency in vivo is still limited. It is of great importance to balance the protection and release of siRNA from nanoparticles (NPs) so as to achieve high efficiency. However, siRNA release profile from CS/siRNA NPs has been rarely concerned. Here, Förster resonance energy transfer technique was adopted for in vitro investigation of siRNA release from CS NPs in lysozyme-contained buffer. The results clearly showed that siRNA molecules experienced a fast and short release phase under lysozyme competition to both CS and siRNA, and then a slow and long release under lysozyme degradation on CS. Moreover, lysozyme competition played more important role than enzymolysis on trigging siRNA release. This preliminary study of siRNA release is the first step to get insight of in vivo siRNA release mechanism from CS/siRNA NPs, which will be helpful to adjust the design of CS/siRNA NPs for balancing the protection and release of siRNA molecules. [ABSTRACT FROM AUTHOR]

The objective of this study was to design a simple, colon targeted drug delivery system by using porous starch (PS), pectin and chitosan. Porous maize starch was prepared by hydrolysis with a combination of α-amylase and amyloglucosidase, and it was characterized by scanning electron microscopy, revealing the formation of porous structures in the starch granules. A Brunauer-Emmett-Teller (BET) specific surface area analysis indicated that the specific surface area of the PS (0.8768–0.9448 m2/g) was 19.88–21.42 times larger than that of native maize starch (0.0441 m2/g). The average pore diameter of the PS granules, as calculated by the Barrett-Joiner-Halenda (BJH) method, was 40.52–62.42 nm. A favorable adsorptive potential of the PS granules was verified by water and soybean oil tests. Doxorubicin was loaded into PS granules, which were then coated with a pectin/chitosan complex solution. The results of confocal laser scanning microscopy (CLSM) demonstrated that doxorubicin was successfully absorbed into the PS granules. In addition, an in vitro simulated digestion method demonstrated the effectiveness of this delivery design, as only a 13.80% release rate of doxorubicin was observed in the upper gastrointestinal tract, whereas release rates of 17.56% and 67.04% were observed for pectin/PS/doxorubicin and pectin/doxorubicin beads, respectively. It was concluded that the use of PS and a pectin/chitosan coating is an effective method for colon targeted drug delivery compared with the simple polysaccharide system. Image • A simple colon targeted drug delivery system was designed. • The sustained release effect of the beads was enhanced by adding porous starch. • The encapsulation efficiency of DOX was increased by porous starch addition. • 86.20% of the loaded doxorubicin could reach the colon. [ABSTRACT FROM AUTHOR]