Researchers have been successful in testing a tiny biosensor in the laboratory that was developed for detecting biomarkers based on traumatic brain injuries.
The biosensor is designed to continuously monitor brain tissues to detect changes related to brain injuries. Image Credit: Getty Images.
In a study reported recently in the journal Small, the scientists of Ohio State University (OSU) say their waterproof biosensor consists of an “unprecedented combination of features” that might enable it to detect alterations in the concentrations of numerous chemicals in the body and transmit the results to researchers in real-time.
The chip seems to be flexible and thinner than human hair, thereby making it less invasive for use in the brain.
We have a long way to go from our tests in the lab, but these findings were very encouraging.
Jinghua Li, Study Co-Author and Assistant Professor, Materials Science and Engineering, Ohio State University
Even though a biosensor like the one the team came up with could exhibit several potential uses, Li and her co-authors specifically focused on how the sensor could be utilized to track patients with traumatic brain injuries (TBI).
Following such an injury, secondary damage can happen that can be detected by variations in potassium and sodium ion concentrations in the cerebrospinal fluid of the brain, stated Li, a member of Ohio State’s Chronic Brain Injury (CBI) Program.
We want a biosensor that is able to continuously monitor brain tissues to detect changes in ion concentrations in the cerebrospinal spinal fluid. Those changes emerge at the secondary state of TBI as an early warning signal of the condition worsening.
Jinghua Li, Study Co-Author and Assistant Professor, Materials Science and Engineering, Ohio State University
The scientists tested the biosensor in an artificial solution that was made by them to mimic cerebrospinal fluid and discovered that it could precisely detect changes in sodium and potassium ion levels that are crucial in TBI.
Besides the tests performed with the artificial cerebrospinal fluid, the team also went on to test the biosensor in human blood serum, in which they were successful in tracking pH levels.
The question is how the working takes place. The chip features electronic components (called field-effect transistors) that, upon sensing the chemical of interest, generate an electrical signal that could be detected and examined outside the body.
Significantly, the scientists came up with calibration standards that address what is known as the “crosstalk” problem.
When we create a biochemical sensor, we want to make sure that the device only responds to the specific chemicals we are interested in, and ignores the crosstalk from other biomarkers. That is difficult to do in a complex system like our body.
Jinghua Li, Study Co-Author and Assistant Professor, Materials Science and Engineering, Ohio State University
If a biosensor can detect changes in the fluids in the brain, the electronics in the chip should be protected from these same fluids, stated Li.
A waterproof encapsulation created from a thin film of silicon dioxide—forged in temperatures above 1000°C—provided high structural integrity as barrier materials in a fluid environment, the study found.
The scientists tested the material in a range of ways, like by placing it in heated fluids and in substances with various pH levels, to determine how long encapsulation could last in the human body.
The outcomes indicate the waterproof encapsulation with a thickness of several hundreds of nanometers could remain at least a few years at body temperature and probably much longer, stated Li.
The biggest problem at present is the chemical sensing elements, which the study indicates would work for only up to a few weeks.
There are also other problems that need to be worked out prior to the biosensor being ready test in animal models and humans, states Li. The response of biotissues to the sensor over an expanded period requires additional study and there are still problems with crosstalk to be resolved, taking into account the complexity of the biosystem, and questions of how to mass-produce the sensors, amongst other matters.
However, this study offers more proof that these sensors have a real future in health care, Li said.
Li said she believes biosensors could be utilized to examine not only ions and neurotransmitters, as in this study but possibly proteins, peptides, nucleotide acids, and other chemicals in the body. It could be a discovery not only for TBI but for other chronic diseases like Alzheimer’s and Parkinson’s disease.
“We believe that the capture and analysis of health data that we could achieve with biosensors are crucial to tracking long-lasting health conditions for early intervention and treatment of diseases,” stated Li
Li performed the study with Yan Dong, a postdoctoral researcher, and graduate students Shulin Chen and Tzu-Li Liu, all in materials science and engineering at Ohio State.
This study was financially supported by the National Center for Advancing Translational Sciences, part of the National Institutes of Health. Assistance was also given by Ohio State’s CBI program and Ohio State’s Center for Emergent Materials, which is a National Science Foundation Materials Research Science and Engineering Center.
Journal Reference:
Dong, Y., et al. (2022) Materials and Interface Designs of Waterproof Field-Effect Transistor Arrays for Detection of Neurological Biomarkers. Small. doi.org/10.1002/smll.202106866.