Tag Archives: bandages

Ouchies no more! Not from bandages, anyway.

An adhesive that US and Chinese scientists have developed shows great promise not just for bandages but wearable robotics too. From a December 14, 2018 news item on Nanowerk,

Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and Xi’an Jiaotong University in China have developed a new type of adhesive that can strongly adhere wet materials — such as hydrogel and living tissue — and be easily detached with a specific frequency of light.

The adhesives could be used to attach and painlessly detach wound dressings, transdermal drug delivery devices, and wearable robotics.

A December 18, 2018 SEAS news release by Leah Burrows (also on EurekAlert but published Dec. 14, 2018), which originated the news item, delves further,

“Strong adhesion usually requires covalent bonds, physical interactions, or a combination of both,” said Yang Gao, first author of the paper and researcher at Xi’an Jiaotong University. “Adhesion through covalent bonds is hard to remove and adhesion through physical interactions usually requires solvents, which can be time-consuming and environmentally harmful. Our method of using light to trigger detachment is non-invasive and painless.”

The adhesive uses an aqueous solution of polymer chains spread between two, non-sticky materials — like jam between two slices of bread. On their own, the two materials adhere poorly together but the polymer chains act as a molecular suture, stitching the two materials together by forming a network with the two preexisting polymer networks. This process is known as topological entanglement.

When exposed to ultra-violet light, the network of stitches dissolves, separating the two materials.

The researchers, led by Zhigang Suo, the Allen E. and Marilyn M. Puckett Professor of Mechanics and Materials at SEAS, tested adhesion and detachment on a range of materials, sticking together hydrogels; hydrogels and organic tissue; elastomers; hydrogels and elastomers; and hydrogels and inorganic solids.

“Our strategy works across a range of materials and may enable broad applications,” said Kangling Wu, co-lead author and researcher at Xi’an Jiaotong University in China.
While the researchers focused on using UV light to trigger detachment, their work suggests the possibility that the stitching polymer could detach with near-infrared light, a feature which could be applied to a range of new medical procedures.

“In nature, wet materials don’t like to adhere together,” said Suo. “We have discovered a general approach to overcome this challenge. Our molecular sutures can strongly adhere wet materials together. Furthermore, the strong adhesion can be made permanent, transient, or detachable on demand, in response to a cue. So, as we see it, nature is full of loopholes, waiting to be stitched.”

Here’s a link to and  a citation for the paper,

Photodetachable Adhesion by Yang Gao, Kangling Wu, Zhigang Suo. https://doi.org/10.1002/adma.201806948 First published: 14 December 2018

This paper is behind a paywall.

Treating bandages with enzymes and polyethylene glycol or cellulase* could make antibacterial nanoparticles better adhere

It’s been a while since I’ve featured research from Iran. This work is focused on bandages, burns, and nanoparticles according to an Oct. 18, 2016 news item on Nanowerk (Note: A link has been removed),

Pre-treating the fabric surface of the bandages used to treat burns with enzymes and polyethylene glycol or cellulase may promote the adhesion of antibacterial nanoparticles and improve their bacteria-repelling ability. These are the findings of a group of scientists from the Islamic Azad University, Iran, published in The Journal of The Textile Institute (“NiO-/cotton- modified nanocomposite as a medication model for bacterial-related burn infection”).

An Oct. 18, 2016 Taylor & Francis (Publishing) Group press release (received via email), which originated the news item, expands on the theme,

Injuries caused by burns are a global health problem, with the World Health Organisation citing 195,000 deaths per year worldwide as a result of burns from fires alone. Burn injuries are particularly susceptible to infections, hospital-acquired or otherwise, with the bacteria Pseudomonas aeruginosa accounting for over half of all severe burn infections.

Noble metal (particularly silver) antimicrobials have long been identified as having potential for combating bacterial infection; however, there are concerns about dressings adhering to wounds and toxic effects on skin cells. Currently, scientists are researching nanoparticles which can be used to introduce these antimicrobial properties into the textiles used in dressings.

The authors of this paper have studied 150 cases to identify the most common infections in burns. In the paper, they also identified a method for giving cotton bandages antibacterial properties by coating the fabric surface with a Nickel oxide (NiO)/organic polymer/enzyme matrix in order to promote their bacteria-resistant qualities and suitability for use on burn victims.

Pseudomonas and Staphylococci infections emerged as the two most common pathogens in the Iran Burn Centre, where the study took place, and the authors evaluated their design of the bandage against these as well as fifteen other strains of bacteria. They conclude by proposing further studies into the combination of bactericidal polymers with bacteria-killing metal-oxide nanoparticles in cotton fabrics. Whilst their current design does not meet the criteria for a susceptibility test, they are hopeful that further studies will reveal the clinical relevance of their design.

Here’s a link to and a citation for the paper,

NiO-/cotton- modified nanocomposite as a medication model for bacterial-related burn infections by Azadeh Basiri, Nasrin Talebian & Monir Doudi. The Journal of The Textile Institute http://dx.doi.org/10.1080/00405000.2016.1222863
Pages 1-9 Published online: 12 Sep 2016

This paper is behind a paywall.

*’Cellulase’ changed to ‘Cellulose’ Nov. 15, 2016 at 1832 PT and changed back again on Nov. 16, 2016. Sorry for the confusion but by the time I published this piece I’d forgotten checking to confirm the existence of cellulase.