Scientists have created a device with a specially crafted polymer layer that detects oxytocin. Distinctive changes of oxytocin concentration in the blood are considered a biomarker of autism and this device could someday aid in early diagnosis of the condition. The sensor was developed by scientists at the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw and published in the journal Biosensors and Bioelectrics.
The device is created using molecular imprinting, a way of ‘stamping’ the shape and properties of molecules onto a polymer matrix. The first step is to introduce a functional monomer into a solution containing the target molecule. After the monomer attaches to binding sites on the molecule, a cross-linking monomer is introduced to bind the functional monomer. The target recognizing layer is formed when polymerization of the cross-linking monomer occurs. This creates a molecular cavity that recognizes the molecule of interest.
For detection purposes, the monomer layers are produced on small gold electrodes that are inserted in a tube with a blood sample. When the oxytocin molecules sink into the cavities of the polymer layer, the electrical capacitance changes, signaling binding.
In experimental tests, the sensor was able to detect micromolar concentrations of oxytocin even when surrounded by molecules of a similar structure. The team is hoping to achieve sensitivity to a nanomolar concentration so a single drop of blood would suffice for the test.
The researchers caution that oxytocin concentration is only one biomarker for autism, and several diagnostic tests should be performed. They have been working on polymer layers that respond to two other autism-associated compounds, melatonin and gamma-aminobutyric acid.
Image: Small amounts of oxytocin, one of the biomarkers of autism, can be detected by a new chemical sensor, designed and fabricated at the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw. Image courtesy of IPC PAS, Grzegorz Krzyzewski.