Biochernila-chameleons
Engineers from Tufts University have developed an ink based on biomaterials that qualitatively and quantitatively determine chemicals released from the body (for example, with sweat and possibly other biological fluids) or in the environment. Ink can be applied to textiles from which clothes, shoes and even face masks are made. They can be used to make complex drawings with high resolution, providing a detailed map of a person's reaction or the nature of the impact. They can simultaneously detect and quantify a wide range of biological states, molecules, and possibly pathogenic microorganisms on the surface of the body.
The use of new biologically active inks by screen printing opens up prospects for the mass production of soft wearable fabrics with a large number of sensors. Fabrics can be used for sewing work uniforms, sportswear and even creating furniture.
The development presented by the Tufts group is based on non-electronic colorimetric detection of analytes.
Biological ink is created from silk. The soluble silk substrate can be modified by embedding various reporter molecules, for example, pH indicators or lactate oxidase to indicate the level of lactate in sweat – the first is an indicator of skin condition or dehydration, and the second can indicate the degree of fatigue of a person.
The pattern on the T-shirt printed with pH-sensitive bioactive ink changes color depending on the acidity of the wearer's sweat. Source: Tufts University.
Inks can be modified due to the versatility of the silk fibroin protein, which allows them to be supplemented with active molecules: chemically sensitive dyes, enzymes, antibodies and many others. Reporter molecules themselves may be unstable, but they become so during storage, being embedded in fibroin.
The ink also contains a thickener (sodium alginate) and a plasticizer (glycerin), which allow them to be used for screen printing and applied not only to clothes, but also to various surfaces such as wood, plastic and paper.
Changing the color of the biochernil pattern provides high-quality information about the presence or absence of the analyte, while the analysis of camera images scanning patterns ranging in size from hundreds of microns to tens of meters can give more accurate information about its quantity.
The technology is based on earlier work by the same group of researchers, they created bioactive silk ink for inkjet printing on laboratory utensils, paper and gloves, which by changing color reported bacterial contamination.
With the new screen printing ink, combined with image analysis, it is possible to obtain a high-resolution color map of reactions over a large area and better understand the general state of the body or the environment. The authors write that they can modernize this method to track air quality and monitor the epidemiological state of the environment.
Article G.Matzeu et al. Large Scale Patterning of Reactive Surfaces for Wearable and Environmentally Deployable Sensors is published in the journal Advanced Materials.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on Tufts Now materials: New smart fabrics from bioactive inks monitor body and environment by changing color.