New patch boosts brightness in medical diagnostic tests

A Universal Fluorescence Enhancer.


Fluorescence-based biosensing and bioimaging technologies are broadly utilized as a part of research and clinical settings to recognize an image of different biological species of interest. While fluorescence-based discovery and imaging procedures are helpful to utilize, they experience poor sensitivity.

For instance, when a patient conveys low levels of antigens in the blood or urine, the fluorescent signal can be weak, making representation and diagnosis difficult. Hence, fluorescence-based identification isn’t generally favored when sensitivity is a key requirement.

Scientists at the Washington University in St. Louis and the Air Force Research Laboratory (AFRL) at Wright-Patterson Air Force Base have developed a high-tech fix, i.e., a plasmonic patch that utilizes metal nanostructures to increase the fluorescence intensity by 100 times in these diagnostic tests. It’s a cheap and easy solution to what’s previously been a vexing diagnostic problem.


The patch is a flexible piece of film about a centimeter square, embedded with nanomaterials. All a researcher or lab tech needs to do is prepare the sample in the usual method, apply the patch over the top, and then scan the sample as usual.

Scientists used methods to boost the signals — for example, depending on enzyme-based amplification — require additional means that draw out the general activity time, and in addition, particular and costly read-out systems in some cases.

Srikanth Singamaneni, professor of mechanical engineering & material science at the School of Engineering & Applied Science, said, “Using fluorescence for detection is very convenient and easy, but the problem is it’s not that sensitive, and that’s why researchers don’t want to rely on it.”

Jingyi Luan, a graduate student in the Singamaneni Lab and primary author of the manuscript, said, “It’s a thin layer of elastic, transparent material with gold nanorods or other plasmonic nanostructures absorbed on the top. These nanostructures act as antennae: they concentrate light into a tiny volume around the molecules emitting fluorescence. The fluorescence is dramatic, making it easier to visualize. The patch can be imagined to be a magnifying glass for the light.”

Singamaneni said the newly developed patch is a cheap fix — costing only about a nickel per application — and one that contains not only research applications but also diagnostics. It could be particularly useful in a microarray, which enables simultaneous detection of tens to hundreds of analytes in a single experiment.

“The plasmonic patch will enable the detection of low abundance analytes in combination with conventional detection methodologies, which is the beauty of our approach,” said Rajesh Naik, chief scientist of AFRL’s 711th Human Performance Wing.

The team recently explained in the journal Light: Science and Applications.