Fabrication of chitosan hydrochloride and carboxymethyl starch complex nanogels as potential delivery vehicles for curcumin.

The purpose of this research was to prepare nanogels by covalent cross-linking carboxymethyl starch (CMS) and chitosan hydrochloride (CHC) as novel delivery systems for curcumin. The spherical structure of CHC-CMS nanogels was verified by transmission electron microscopy. Fourier transform infrared spectroscopy confirmed that the amide linkage was formed between CHC and CMS. X-ray diffraction data exhibited that the crystalline structure of CHC was destroyed after covalent cross-linking with CMS, which further confirmed that the CHC-CMS nanogels were formed. Furthermore, the nanogels behaved as viscoelastic solids over the entire frequency range. Meanwhile, the nanogels showed excellent pH-sensitivity and high encapsulation efficiency of curcumin (89.49%-94.01%). Compared to free curcumin, curcumin encapsulated in nanogels displayed sustained release profile in simulated gastrointestinal conditions. These results suggested that the nanogels had been successfully fabricated and could be used as ideal carriers for curcumin and other bioactive compounds in functional foods.

Bio-inspired annelid robot: a dielectric elastomer actuated soft robot.

Biologically inspired robots with inherent softness and body compliance increasingly attract attention in the field of robotics. Aimed at solving existing problems with soft robots, regarding actuation technology and biological principles, this paper presents a soft bio-inspired annelid robot driven by dielectric elastomer actuators (DEAs) that can advance on flat rigid surfaces. The DEA, a kind of soft functional actuator, is designed and fabricated to mimic the axial elongation and differential friction of a single annelid body segment. Several (at least three) DEAs are connected together into a movable multi-segment robot. Bristles are attached at the bottom of some DEAs to achieve differential friction for imitating the setae of annelids. The annelid robot is controlled by periodic square waves, propagating from the posterior to the anterior, which imitate the peristaltic waves of annelids. Controlled by these waves, each DEA, one-by-one from tail to head, anchors to the ground by circumferential distention and pushes the front DEAs forward by axial elongation, enabling the robot to advance. Preliminary tests demonstrate that a 3-segment robot can reach an average speed of 5.3 mm s-1 (1.871 body lengths min-1) on flat rigid surfaces and can functionally mimic the locomotion of annelids. Compared to the existing robots that imitate terrestrial annelids our annelid robot shows advantages in terms of speed and bionics.

Extraction optimization by response surface methodology of mucilage polysaccharide from the peel of Opuntia dillenii haw. fruits and their physicochemical properties.

In this study, response surface methodology (RSM) was employed to optimize microwave-assisted extraction (MAE) technology of mucilage polysaccharide from the peel of Opuntia dillenii haw. fruits (OFPP), and the physicochemical characteristics of OFPP were also investigated. The three parameters were the ratio of water to raw material (30-40ml/g), microwave power (300-400W) and extraction time (120-180s). The results indicated that the yield of OFPP was 15.62±0.37% under the optimum extraction conditions. Compared with MAE, the OFPP yield by hot water extraction (HWE) was 13.36±0.71%. In addition, the rheological properties of OFPP were also explored. The OFPP obtained by HWE exhibited a lower viscosity compared with that by MAE. The FT-IR spectra analysis, scanning electron microscopy (SEM) observation and thermogravimetric analysis (TGA) revealed that there were strong interactions between Ca(2+) and OFPP, which resulted in the high viscosity, different microstructure and thermal stability of OFPP.