A simple process to tune wettability of pectin-modified silanized glass

Low-temperature plasma modification, structural characterization and anti-diabetic activity of an apricot pectic polysaccharide

To fully research the anti-diabetic activity of apricot polysaccharide, low temperature plasma (LTP) was used to modify apricot polysaccharide. The modified polysaccharide was isolated and purified using column chromatography. It was found that LTP modification can significantly improve the α-glucosidase glucosidase inhibition rate of apricot polysaccharides. The isolated fraction FAPP-2D with HG domain showed excellent anti-diabetic activity in insulin resistance model in L6 cell. We found that FAPP-2D increased the ADP/ATP ratio and inhibited PKA phosphorylation, activating the LKB1-AMPK pathway. Moreover, FAPP-2D activated AMPK-PGC1α pathway, which could stimulated mitochondrial production and regulate energy metabolism, promoting GLUT4 protein transport to achieve an anti-diabetic effect. The Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy data showed that the LTP modification could increase the CH bond content while decreasing the C-O-C/C-O bond content, indicating that LTP destroyed the C-O-C/C-O bond, which enhanced the anti-diabetes activity of the modified apricot pectin polysaccharide. Our findings could pave the way for the molecular exploitation of apricot polysaccharides and the application of low-temperature plasma.

Hierarchically Structured, All-Aqueous-Coated Hydrophobic Surfaces with pH-Selective Droplet Transfer Capability

Often inspired by nature, techniques for precise droplet manipulation have found applications in microfluidics, microreactors, and water harvesting. However, a widely applicable strategy for surface modification combining simultaneous hydrophobicity and pH-sensitivity has not yet been achieved by employing environmentally friendly assembly conditions. The introduction of pH-responsive groups to an otherwise fluorinated polyphosphazene (PPZ) unlocks pH-selective droplet capture and transfer. Here, an all-aqueous layer-by-layer (LbL) deposition of polyelectrolytes is used to create unique hydrophobic coatings, endowing surfaces with the ability to sense environmental pH. The high hydrophobicity of these coatings (ultimately reaching a contact angle >120° on flat surfaces) is enabled by the formation of hydrophobic nanoscale domains and controllable by the degree of fluorination of PPZs, polyamine-binding partners, deposition pH, and coating thickness. Inspired by the hierarchical structure of rose petals, these versatile coatings reach a contact angle >150° when deposited on structured surfaces while introducing a tunable adhesivity that enables precise droplet manipulation. The films exhibited a strongly pronounced parahydrophobic rose petal behavior characterized through the contact angle hysteresis. Depositing as few as five bilayers (∼25 nm) on microstructured rather than smooth substrates resulted in superhydrophobicity with water contact angles >150° and the attenuation of the contact angle hysteresis, enabling highly controlled transfer of aqueous droplets. The pH-selective droplet transfer was achieved between surfaces with either the same microstructure and LbL film building blocks, which were assembled at different pH, or between surfaces with different microstructures coated with identical films. The demonstrated capability of these hydrophobic LbL films to endow surfaces with controlled hydrophobicity through adsorption from aqueous solutions and control the adhesion and transfer of water droplets between surfaces can be used in droplet-based microfluidics applications and water collection/harvesting.