Bioactive Ink Printed On Wearable Textiles Can Map The Whole Body Surface.

Researchers at the school of engineering at Tufts University developed biomaterial based ink to respond and quantify chemicals released from human body (such as sweat and other biological fluids) or surrounding environment by changing colors. This ink can provide a detailed map of human reactions or exposures in complex patterns and high resolution screen printing on textiles such as clothing, shoes and even masks. The progress of wearable sensing reported in Advanced Materials magazine can make use of traditional clothing and uniform to detect and quantify various biological conditions, molecules and possible pathogens on the body surface.

"The use of new bioactive inks and very common screen printing methods provide promising opportunities for large-scale production of soft and wearable fabrics with a large number of sensors. These sensors can be applied to detect a series of conditions," said Fiorenzo Omenetto, Professor of communication at the tufts Institute of engineering. "These fabrics may eventually appear in the workplace uniform, sportswear, and even furniture and building structures. "

Wearable sensing devices have attracted considerable interest in monitoring human performance and health. Many of these devices have been invented to add electronic components to wearable patches, wristbands and other configurations to monitor local or overall physiological information, such as heart rate or blood sugar. The Taft team's research used a different and complementary approach, using sensor clothing to conduct non electronic and colorimetric detection of many theoretical analytes, which can be distributed in very large areas: from one patch to the whole body, or even more.

The component that makes sensing clothing possible is the bio activated silk based ink. The soluble silk matrix in these ink formulations can be modified by embedding various "report" molecules, such as pH sensitive indicators, or enzymes like lactate oxidase to indicate lactic acid levels in sweat. The former can be an indicator of skin health or dehydration, and the latter can indicate wearer's wearability. Because of its versatile properties, silk cellulose can be modified by reactive molecules such as chemically sensitive dyes, enzymes and antibodies to create many other ink derivatives. Although the reporter itself may be unstable, they can become stable when they are embedded in silk cellulose from the ink formula.

The ink is formulated through screen printing with a combination of Thickener (sodium alginate) and plasticizer (glycerol). Screen printing biological ink can be used just like any ink developed for screen printing, so it can be applied not only to clothes but also to various surfaces, such as wood, plastic and paper, so as to produce patterns from hundreds of microns to tens of meters. Although the color changes presented by ink can provide visual clues for the existence or absence of analytes, the more accurate quantities and high-resolution and sub millimeter map information can be gathered by using camera imaging analysis to scan clothing or other materials.

Based on the previous work of the same researcher, the technology developed bioactive ink for inkjet printing to create Petri dishes, paper sensors and laboratory gloves, which can be used to indicate bacterial contamination by changing colors.

"The screen printing method provides the equivalent of having a large, multi-channel sensor array that covers a wide area of the body. If worn as clothing, even on large surfaces, such as inside the room," says Giusy Matzeu, first author of the biomedical engineering research assistant and teaching at the tufts Institute of engineering. "Combined with image analysis, we can obtain large area high-resolution color reaction maps and have a deeper understanding of the whole physiological or environmental state. Theoretically, we can extend this method to tracking air quality or supporting epidemiological environmental monitoring. "

In fact, this method used ordinary printing technology and opened up a way for creative applications, which was explored by Laia Mogas-Soldevila, a doctor recently graduated from Tufts University, in Omenetto's silk laboratory. Mogas-Soldevila made beautiful tapestries in American and European museums. These displays are interactive. Visitors can spray different non-toxic chemicals onto the fabric and watch the pattern change. The title of the paper is "LargeScale Patterning of Reactive Surfaces for Wearable and Enviro". Nmentally Deployable Sensors.