#hydrogels

Tea compound boosts seaweed hydrogel strength fivefold, while tuning adhesion and breakdown

Could wound healing dressings adhere better, and could drug delivery patches become more sophisticated? A KAIST research team has developed a technology that leverages natural ingredients derived from plants to increase the strength of a seaweed-based hydrogel (a gel material that contains a large amount of water while maintaining its shape) by more than fivefold, while also controlling its adhesiveness and degradation rate. The research team, led by Professor Haeshin Lee of the Department of Chemistry, developed a new material design strategy that uses tannic acid—a type of polyphenol, which is a natural antioxidant abundant in tea and fruits—to enhance the mechanical strength and adhesiveness of seaweed-derived hydrogel and control its degradation rate.

Access to clean water is being strained as the human population increases and contamination impacts freshwater sources. Devices currently in development that clean up dirty water using sunlight can only produce up to a few gallons of water each day. But now, researchers in ACS Central Science report how loofah sponges inspired a sunlight-powered porous hydrogel that could potentially purify enough water to satisfy someone's daily needs—even when it's cloudy.

Previously, researchers have suggested that sunlight-driven evaporation could be a low-energy way to purify water, but this approach doesn't work well when it's cloudy. One solution could be temperature-responsive hydrogels, specifically poly(N-isopropyl acrylamide) (PNIPAm), that switch from absorbing water at cooler temperatures to repelling it when heated. However, conventional PNIPAm gels can't generate clean water fast enough to meet people's daily needs because of their closed-off pores. Conversely, natural loofahs, which many people use to exfoliate in the shower, have large, open and interconnected pores. So, Rodney Priestley, Xiaohui Xu, and colleagues wanted to replicate the loofah's structure in a PNIPAm-based hydrogel, yielding a material that could rapidly absorb water at room temperature, and rapidly release purified water when heated by the sun's rays under bright or cloudy conditions.

Good Suspension

New method of culturing intestinal organoids in suspended basement membrane extract hydrogels enables their production to be scaled up

Read the published research paper here

Image from work by Julia Y. Co and colleagues

Complex in vitro Systems, Safety Assessment, Genentech, South San Francisco, CA, USA

Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)

Published in Scientific Reports, June 2023

“The method provides a way to catch microplastic particles of a size that the human eye cannot detect. These are particles with a diameter of only 100 nanometers.”

Super sponge can remove toxic dyes from industrial wastewater

Colors brighten our lives and help define countless items we use daily—from the vibrant clothes we wear to decorative paper and packaging materials. What adds different colors to these things? Dyes, which bind themselves to the structure of the material they are coloring. For example, methylene blue (MB) is a dye used to color paper, leather products, silk and wool, and is also employed as a diagnostic agent and in the rubber and cosmetic industries. But what happens after these dyes have served their purpose? According to a recent study, billions of tons of dye-containing wastewater enter water systems every year. Some 80% of such wastewater generated in low- and middle-income nations is used directly for irrigation or released untreated into water sources.

An everyday sweetener offers a surprisingly powerful engine for transparent, stretchable electronics

Professor Kyungwho Choi's team of the School of Mechanical Engineering at Sungkyunkwan University, in collaboration with Professor Jinsoo Kim's team in the Department of Chemical Engineering at Kyung Hee University, have proposed a strategy that simultaneously overcomes the limitations of conventional hydrogel-based triboelectric nanogenerators (TENGs)—namely low output performance, poor mechanical strength, and insufficient transparency—by utilizing biomimetic stevia. How stevia transforms hydrogel performance By incorporating stevia into polyvinyl alcohol (PVA), the abundant hydroxyl groups (-OH) simultaneously reinforced the hydrogen bond-based crosslinking structure and crystalline domains, dramatically improving both mechanical strength and ionic conductivity. The work is published in the journal Advanced Materials.

Natural hydrogel can make personal hygiene products greener

A natural, superabsorbent material developed at the University of Waterloo could dramatically reduce the environmental impact of personal hygiene products like diapers, menstrual pads and tampons. Unlike synthetic absorbent materials in commercial hygiene products, which are expected to take centuries to break down, the new hydrogel degrades harmlessly in soil within three months. "Our goal was a scalable, economical process for producing eco-friendly materials to replace the non-degradable components currently used in personal hygiene products," said Dr. Tizazu Mekonnen, a chemical engineering professor at Waterloo. "Our work demonstrates that we can design high-performance alternatives that work extremely well without leaving hundreds of years of waste behind for future generations."