Optical fiber-illuminated pajamas treat jaundiced newborns

02 Nov 2017

"Satin weave" onesie frees babies from incubators, while delivering blue light photo-therapy more safely, says EMPA.

Babies who suffer from jaundice after birth are often treated with shortwave light which means they need to remain in an incubator and have their eyes protected by a mask. Infant jaundice is a common phenomenon, as babies' metabolisms are often not very resilient within the first few days after birth.

Today, light therapy in incubators can treat problems caused by jaundice if it is applied in time. Light intensities of 30 microwatts per square centimeter in the blue spectrum transform toxic bilirubin into a soluble form that can easily be removed by an infant's immature organs.

Now, scientists at the Swiss Federal Laboratories for Materials Science and Technology (EMPA) have developed illuminated pajamas woven with optical fibers to replace the conventional treatment. This means newborns so affected can recover while in a parent’s arms and without needing the mask.

The researchers in EMPA's Biomimetic Membranes and Textiles division, led by Luciano Boesel, have significantly improved the not-so-child-friendly procedure by combining the treatment with the needs of the newborns: The team has developed illuminated pajamas for babies that turn the treatment into what they are calling "a wellness experience".

To make the special pajamas, Boesel's team created textiles with optically-conductive fibers woven into them. Battery-operated LEDs serve as a light source for the light-conducting threads. Together with conventional thread, the optical fibers are woven into a satin type of material that distributes the light supply evenly. The work has been reported in Biomedical Optics Express.

Satin fabric is ideal

Depending on the weaving process, the light from the optical fibers penetrates the fabric differently. A satin fabric, in which the threads cross each other as seldom as possible, was found to clearly out-shine a simple linen fabric.

With a diameter of around 160µm, the dimensions of the optical fibers match that of regular threads. Boesel's team determined the appropriate angle at which the threads must be bent during weaving so that the blue light stays in the therapeutic wavelength range of around 470 nm but is emitted onto the baby's skin, rather than staying in the fabric.

They discovered that the optimal result was achieved in a weaving process with a so-called 6/6 bond, which produces the satin material. Here, the optical threads have particularly few cross points with the traditional thread and are bent such that the light is emitted uniformly over the baby’s skin.

The photonic textiles woven in this manner can be made into a romper or a sleeping bag so the little patient is clothed, and can be held and fed. And because the pajamas can be produced for commercial use so they only radiate light inward, onto the baby's skin, it is no longer necessary for the newborn to wear a restrictive mask.

Everyday wear

Maike Quandt, lead author of the publication, says the illuminated fabrics are also suitable for everyday wear. "The photonic textiles are washable and tolerated well by the skin," he commented. In a thermoregulation model, the researchers studied how breathable the light textiles are. One of EMPA's own skin models proved that the pajamas also perform well in terms of friction on the skin, comparable with the comfort of a typical onesie.

The prototype of the pajamas currently radiates blue light from the photonic textiles at a lower light intensity. "For commercial production, the light intensity of the pajamas must therefore be increased somewhat," said Quandt. "This would only require the use of more powerful LEDs."