Country for PR: Japan
Contributor: Kyodo News JBN
Friday, October 28 2022 - 17:00
Novel, Biocompatible UV Light Absorber: WPI-MANA
TSUKUBA, Japan, Oct. 28, 2022 /Kyodo JBN-AsiaNet/ --

An International research team at the International Center for Materials 
Nanoarchitectonics (WPI-MANA) has developed a biocompatible ultraviolet (UV) 
light-shielding compound from naturally occurring aqueous iron(III), 
hereinafter aqua-Fe(III), complexes stabilized inside a layered silicate 


UV-absorbing materials are important to many industries, spanning healthcare, 
cosmetics, and material protection, among others. Their low environmental 
impact has made titanium dioxide (TiO2) nanoparticles the most commonly used UV 
absorber in sunscreens and cosmetics. However, many health concerns -- 
including its toxicity to cells and carcinogenic potential -- surround the use 
of TiO2. This has triggered the search for alternative safer, biocompatible, 
yet affordable UV-shielding compounds.

Now, researchers at WPI-MANA have prepared a new UV-absorbing material using 
biocompatible and readily available aqua-Fe(III) complexes. These complexes, 
which are widely available in biological systems, are naturally biocompatible. 
However, they are difficult to isolate and stabilize.

The WPI-MANA team, led by Dr. Yusuke Ide, used a layered silicate to stabilize 
the dimeric state of aqua-Fe(III) complexes. "The issue with aqua-Fe(III) 
complexes is that they are only stable in extremely acidic solutions, which 
presents a health hazard and is not feasible for use in products requiring UV 
shields. We use a material that has gaps, or pores, that are the size of the 
iron complex dimer. The aqua-Fe(III) dimer is imbedded into the silica pores 
and 'stuck' inside, thereby remaining stable even outside an acidic 
environment," explains Ide.

The silica itself is flexible, biocompatible, and affordable, and doesn't react 
with UV light, meaning it doesn't interfere with the UV-shielding properties of 
aqua-Fe(III). Moreover, when mixed with a natural oil, it forms a UV-absorbing 
material which could be interesting to the art and manufacturing industries. 
"UV damage to paintings and other goods is a standard problem, and our material 
could be used as a protective layer. It is more transparent than -- and 
functions just as well as -- conventional TiO2 coatings," concludes Ide.

With a variety of silicate frameworks available, this new method of 
manufacturing UV-shielding materials provides a clear blueprint for developing 
future applications of the same.

Research Highlights Vol. 80

MANA Research Highlights

Source: International Center for Materials Nanoarchitectonics (WPI-MANA), 
National Institute for Materials Science (NIMS)