Researchers at the University of Cambridge recently published a paper in the journal Advanced Optical Materials on a test they created that uses responsive holograms to monitor conditions such as diabetes, cardiac function, infections, electrolyte or hormones imbalance.

The smart holograms respond to the presence of certain compounds by changing color. They can be used to test blood, breath, urine, saliva or tear fluid for compounds such as glucose, alcohol, hormones, drugs or bacteria. A change in color of the hologram could simply be checked against a color gradient to give a result.

An interdisciplinary team of researchers at the University of Cambridge created the tests by impregnating hydrogel, a highly absorbent material similar to contact lenses, with silver particles. A single laser pulse causes the silver nanoparticles to form into three-dimensional holograms of predetermined shapes in a fraction of a second. The presence of certain compounds then causes the hydrogels to shrink or swell, resulting in a change of color of the hologram.

Ali Yetisen, PhD student in the Department of Chemical Engineering & Biotechnology at the University of Cambridge, who led the research says that “currently, a lot of medical testing is performed on large, expensive equipment. While these sorts of inexpensive, portable tests aren’t meant to replace a doctor, holograms could enable people to easily monitor their own health, and could be useful for early diagnosis, which is critical for so many conditions.”

The holographic sensors can easily be mass produced. It is estimated that they would cost ten pence (approximately 17 cents) each, making them especially useful for use in developing nations where current glucose tests can be cost prohibitive. The sensing process is reversible, allowing for the sensors to be reused many times before easily being disposed of.

“In addition to medical applications, the holographic technology also has potential uses in security applications, such as the detection of counterfeit medicine, which is thought to cause hundreds of thousands of deaths each year,” said Dr Fernando da Cruz Vasconcellos, Post-Doctoral Researcher at University of Cambridge and co-author of the study. Clinical trials of the holographic sensors are currently being held at Addenbrooke’s Hospital, part of Cambridge University Hospitals in the United Kingdom.

Source: University of Cambridge