Several healthinnovations or disruptive technologies can be identified that might, at some point in the future, displace established laboratory medicine technologies and practices.  One of these highly desirable technologies is non-invasive testing of glucose-levels in the blood.  Blood testing is the standard option for checking glucose levels, however, it can lead to frustration on the patient’s part, a lack of adherence, as well as controversy surrounding the use of this invasive technique by non-insulin treated patients with type 2 diabetes.  Now, a study from researchers at University of Houston develops a new technology which could allow non-invasive testing via a contact lens that samples glucose levels in tears. The study is published in the journal Advanced Materials.

Previous studies show that glucose is present not only in the blood but also in tears, and thus accurate monitoring of the glucose level in human tears by employing a contact-lens-type sensor can be an alternative approach for noninvasive glucose monitoring.  It has been shown that glucose is a good target for optical sensing, and especially for what is known as surface-enhanced Raman scattering spectroscopy.  However, the question is whether researchers have a detector that is capable of mining tears, and how significant is it for real diagnostics.  The current study develops a contact lens which uses Raman spectroscopy analysis to mine glucose levels from tears.

The current study develops a tiny device which optimizes the use of surface-enhanced Raman scattering to take advantage of the technique’s ability to detect small molecular samples.  The lab explains that surface-enhanced Raman scattering uses information about how light interacts with a material to determine properties of the molecules that make up the material.  Results show that their device enhances the sensing properties of the technique by creating ‘hot spots,’ or narrow gaps within the nanostructure which intensified the Raman signal.

The group state that current technologies focus primarily on enzyme-based electrochemical sensing which requires multiple nontransparent electrodes to be integrated.  They go on to add that, however, their technique uses 3D stacking of plasmonic nanostructures, enabled by a solvent-assisted nanotransfer printing (S-nTP) technique, to provide extremely dense and regular hot spot arrays for highly sensitive surface-enhanced Raman spectroscopy (SERS) analysis.

The team surmise that they developed the glucose sensing contact lens to demonstrate the versatility of the technology. They go on to add that it is known that glucose is present in tears, but how tear glucose levels correlate with blood glucose levels hasn’t been established. For the future, the researchers state the more important finding is that the structure is an effective mechanism for using surface-enhanced Raman scattering spectroscopy.

Source: University of Houston