A collaboration of research teams in South Korea have created an intraocular (IOL) implant to detect the early stages of Alzheimer’s disease. Their findings were recently published in Bioactive Materials.
Tell me about this implant.
Scientists developed an implantable biosensing system created by mounting a bioresponsive hydrogel-based sensing module that detects different biomarkers in the aqueous humor on an IOL to express a signal in a moiré pattern. The IOL can be inserted directly into the eye.
What is a moiré?
A moiré pattern (or moiré fringe) occurs when regularly repeating shapes are continuously combined and recombined, creating visual stripes that correspond to differences in the overlapping shapes.
In this study, the moiré pattern was created by overlapping hydrogel and reference gratings with different pitch sizes, and then quantitatively monitored using a customized moiré optical microscope.
Tell me more.
The key test of the system was noted by diffusing target proteins into the hydrogel, which caused subsequent binding to corresponding antibodies of which produced additional crosslinks, shrinking the material.
These patterns allowed for an easier signal readout and more sensitive detection compared to a direct measurement of physical changes to the hydrogel material. (via)
How does it work?
The hydrogel pattern contracts when reacting to the target protein biomarker in the aqueous humor, and from there is detected using changes in the moiré signal. The signal enables detection with more sensitivity than other methods that directly detect hydrogel pattern changes. (via)
And how does this compare to traditional biosensors?
Traditional biosensors typically do not use a detection method that directly detects biomarkers; the use of a moiré signal allows for direct biomarker detection without using electrochemical or fluorescent labels—removing the need for an external power or light source and allowing it to be implanted within the body.
Significance?
The potential for the implant lies in the enhanced velocity to directly diagnose neurological diseases like Alzheimer’s, Parkinson’s disease, and dementia.
The possibilities of bypassing traditional methods—including blood tests and tear film analysis—in exchange for an intraocular bioresponsive system might prevent progression by early detection, along with the inherent social costs caused by these neurodegenerative diseases. (via)
Further research will be conducted to make the technology available to be marketed for commercial use.