The World's Smallest Mona Lisa is About a Third of the Width of a Human Hair

Researchers at Georgia Institute of Technology have painted the smallest-ever image of Mona Lisa. The painting was created using an atomic force microscope and a process called ThermoChemical NanoLithography (TCNL) and is painted on a substrate that is 30 microns in width or about one-third the width of a human hair.

The technique involved controlling nanoscale chemical reactions on a substrate. A heated cantilever was used to control the molecules at specified locations on the substrate with higher heat giving lighter shades of grey to the painting and lower heat giving darker shades. The distance between each pixel is about 125 nanometers.

The painting by Keith Carroll from Georgia Tech and colleagues proves that it is possible to create nanoscale devices using the latest technique as it could control concentration of molecules on small-scale. Currently, it is difficult to achieve the desired chemical concentration on a small-length scale.

They have called their nanoscale painting the "Mini Lisa".

"By tuning the temperature, our team manipulated chemical reactions to yield variations in the molecular concentrations on the nanoscale. The spatial confinement of these reactions provides the precision required to generate complex chemical images like the Mini Lisa," said Jennifer Curtis, an associate professor in the School of Physics and the lead author of the study.

The Georgia Tech TCNL research collaboration used amine groups to create the chemical gradient used in the painting. According to the researchers the technique could be extended to suit other chemicals as well.

"We envision TCNL will be capable of patterning gradients of other physical or chemical properties, such as conductivity of graphene," Curtis added, according to a press release. "This technique should enable a wide range of previously inaccessible experiments and applications in fields as diverse as nanoelectronics, optoelectronics and bioengineering."

The study is published in the journal Langmuir.

The real Mona Lisa measures about 30 by 21 inches (77 by 53 centimeters) and is one of the most recognizable faces in the world. She has been on T-shirts and coffee mugs and this isn't the first time that science has used the painting to demonstrate an achievement; earlier this year, NASA beamed an image of Mona Lisa from Earth to the Lunar Reconnaissance Orbiter (LRO), demonstrating the first laser communication.

An article by Jeanna Bryner decodes some fascinating secrets of the Mona Lisa.