When a newborn is being treated for jaundice, they lay alone, naked and with its eyes covered to shield it from an incubator's light. Irradiation with blue light in an incubator is necessary because toxic decomposition products of the blood pigment hemoglobin are deposited in the skin in newborns that have jaundice. Researchers from the Empa division Biomimetic Membranes and Textiles have now 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 a wellness experience.
The material research team — led by Luciano Boesel — created textiles with optically conductive fibers woven into them. Battery-operated LEDs serve as a light source for the light conducting threads. With conventional thread, the optical fibers are woven into a satin material that distributes the light supply evenly throughout the fabric.
The diameter of the optical fibers is 160 microns, the same size of regular threads. Boesel’s team determined the appropriate angle at which the threads must be bent during weaving so the blue light stays in the therapeutic wavelength range of 470 nanometers, but it is emitted onto the baby’s skin rather than staying in the fabric. The best result was achieved in a weaving process with a so-called 6/6 bond, that produces a satin cloth. The optical threads have a few cross points with the traditional thread and are bent in an ideal way to the light is emitted uniformly over the skin.
The phototonic textile woven in this way can be made into a romper or a sleeping bag so the little patient is clothed and can be held and fed. Because the pajamas can be produced for commercial use so they only radiate light inward, it is no longer necessary for the newborn to wear an annoying protective mask. Unlike the incubator, where the treatment light shines on the infant’s face, the shortwave radiation of the light pajamas doesn’t reach the baby’s sensitive eyes.
Maike Quandt, the lead author, says the illuminated fabrics are suitable for everyday wear. "The photonic textiles are washable and tolerated well by the skin," he said. In a thermoregulation model, the researchers studied how breathable the textiles are. One of Empa’s skin models proved that the pajamas also perform well in terms of friction on the skin. “The satin fabric is smooth and matches the wearing comfort of a typical baby onesie," the material researcher says.
Infant jaundice is a common issue because babies’ metabolisms are not very resilient within the first few days after birth. Normally, the liver disposes of toxins in the body. With hemoglobin degradation, the child’s liver may still be overwhelmed. If the toxic degradation product bilirubin accumulates in large amounts, visible yellow deposits occur in the skin. The situation then becomes dangerous if the bilirubin exceeds a certain threshold and the yellow pigment damages the brain. In a few cases of jaundice, the brain damage can only be prevented by a blood transfusion.
Today, light therapy in incubators prevents this dramatic development if it is applied in time. Light intensities of 30 microwatts per square centimeter in the blue spectrum transform the toxic bilirubin into a soluble form that can be easily removed by the baby’s immature organs. The prototype of the pajamas currently radiates blue light from phototonic textiles at a lower light intensity.
"For commercial production, the light intensity of the pajamas must, therefore, be increased somewhat," says Maike Quandt. But this problem likely has a simple solution: the use of stronger LEDs.
The paper on this research was published in the journal Biomedical Optics Express.