The article that we discuss today, is about the progression of Alzheimer's disease and a new way to detect this disease early. It points out that amyloid-beta peptides (Aβ) and tau proteins are useful clinical biomarkers for the diagnosis and monitoring of Alzheimer's disease. Testing the presence of these peptides can currently be done by liquid biopsy, which involves analyzing circulating biomarkers in bodily fluids, as a potential diagnostic and monitoring tool for Alzheimer's disease.
Yet there is the need to purify biomarkers of Alzheimer's disease, because of their low concentrations in blood plasma. Various isolation methods have been used, but they suffer from limitations such as long processing times, low yields, and poor reproducibility. Moreover, existing biosensors for detecting biomarkers of Alzheimer's disease are unimodal and measure only one detection parameter, which limits their versatility and accuracy. The authors of this article propose the use of acoustofluidics, which combines acoustics and microfluidics, as a multimodal platform to isolate and detect biomarkers of Alzheimer's disease. Their platform includes an acoustofluidic separation chip to isolate biomarkers and a multimodal biosensor that combines surface-enhanced Raman scattering (SERS) and electrochemical immunosensors. This platform aims to improve the diagnostic accuracy and reliability of the detection of Alzheimer's disease biomarkers.
Acoustofluidics is a technology that combines acoustics and fluid mechanics to manipulate and separate particles or cells using acoustic waves in a microfluidic system. In this case, it is used for molecule separation and involves the use of interdigital transducers (IDTs) which are powered using a function generator and an RF amplifier.
Other technologies used include thermoelectric cooling, microfluidics, microscopy, nanoparticle tracking analysis, microfabrication techniques, surface-enhanced Raman spectroscopy, Raman spectrophotometry, and electrochemical measurements.
Surface Enhanced Raman Spectroscopy (SERS) is a technique used for the highly sensitive detection and analysis of molecules.
Overall, the authors present their acoustofluidic multimodal biosensor as a promising tool for the early diagnosis of Alzheimer's disease with a potential for clinical translation. However, the scientists only examined plasma samples from only 10 patients with Alzheimer's disease and 7 healthy controls of similar ages and physiological conditions. There is no information about the provenance of these samples. This largely dampens the excitement of the narration. In fact, statistically, no conclusion can be drawn from such a small sample. Moreover, the proposed test is extremely complex.
In fact, the ideal would be a simple blood test like the Galleri test from GRAIL Bio UK Ltd, which is able to detect multiple cancers from a single blood test. Indeed for a general practitioner who does not have recent training in neurology, it is not immediately obvious when he has the patient in front of him, which test would be necessary to make him pass to know if his symptoms are indeed those of Alzheimer's disease. With a simple blood test, GPs could decide what to do next without fear of ordering an unnecessary test.