The global burden of cancer is estimated (WHO) at 19.3 million new cases and 10 million deaths each year. About 30% of new cases could be prevented and about the same proportion could be cured through earlier detection. This sensor is in fact a “lab on a chip” capable of carrying out complex biochemical analyses. This type of approach is considered one of the most promising for the early detection of cancer.
A hybrid nanophotonic-microfluidic sensor for highly sensitive analysis
The sensor is capable of performing a comprehensive set of blood tests, as well as detecting cancer biomarkers at an early stage using a very small amount of the patient’s blood: ideally, researchers are aiming for 1 drop of blood. “At the push of a button, the doctor would see if the parameters are normal or if further tests are needed.”
The current device consists of nanophotonic optical sensors on a chip in combination with microfluidic channels above the sensor surface. Fluids or gases pumped through the channels affect the propagation of optical radiation in highly sensitive nanophotonic devices, changing the spectral characteristics at the output. By analyzing these changes, researchers can determine the composition of the sample. The small size of the microfluidic channels that deliver samples to sensors allows results to be obtained even from very small samples, which can be valuable when on-site analysis is not possible and samples must be transported elsewhere for analysis.
On the biomarkers used: human blood contains certain components that can be valuable for preliminary diagnostics of oncological diseases. These components include extracellular vesicles (exosomes). Exosomes are microscopic vesicles released into the intercellular space by cells of tissues and organs. Cells communicate with each other using these extracellular vesicles, including exosomes, to send messages, however, certain factors, internal (genetic predisposition) or external (environmental, such as radiation), can disrupt the normal functioning of a cell, causing it to send the wrong messages, resulting in uncontrolled cell division and tumor growth. Thus exosomes can constitute tumor markers.
Exosomes, early biomarkers: At an early stage of cancer, blood concentrations of exosomes tend to increase to analytically significant values, signaling the presence of cancer, making exosomes a valuable biomarker in oncology. It is these exosomes that are detected by the new sensor.
First conclusive tests: the first tests focused not on blood samples but on aqueous solutions of isopropyl alcohol at 20 different concentrations, from 0.08% to 72%. Since the alcohol is very soluble in water, it was possible to use very low concentrations. The sensor has demonstrated the ability to detect both very low concentrations and 2 components at once, but the researchers expect to be able to analyze more components simultaneously – via more microfluidic channels.
The miniaturization of the device is the second challenge: “We want to achieve a compact and portable device for rapid testing that will reduce the time and cost of cancer diagnosis, monitoring and evaluation of response to treatment.”