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Tuesday, 25 March 2014

Artificial micromotors have been shown to improve miniaturized immunoassays

A study to be published in Small unveils the first surface-based biosensing system to be assisted by micromotors. The work was conducted by the ICN2 Nanobioelectronics and Biosensors Group, led by ICREA Prof. Dr. Arben Merkoci.

Immunoassays are biochemical tests that detect the presence or quantity of particular types of molecules in solutions.  These tests use antibodies as the detectors, which are typically fixed to a surface that is exposed to the solution to be analyzed.  Antibodies are proteins made by the immune system to identify foreign objects, and they have the ability to bind only to specific molecules in a complex mixture of molecules, making them ideal detectors for biological and environmental solutions.  As a result, immunoassays are a common tool at hospitals, in medical laboratories, and for research.  They are also useful for detecting contaminants in food and water.  Scientists are trying to miniaturize immunoassays to make them faster and more efficient, but maintaining accuracy is challenging with the reduced sample volumes in miniaturized systems.

In the upcoming issue of Small, ICN2 researchers report that the sensitivity and accuracy of miniaturized immunoassays are improved with the help of the hydrodynamic motion generated by self-propelled artificial micromotors.  The study was led by the ICN2 Nanobioelectronics and Biosensors Group, with Dr. Eden Morales-Narvaez and Dr. Maria Guix (the paper’s first authors), Dr. Carmen Mayorga, Dr.Mariana Medina, and the group’s leader, ICREA Prof. Dr. Arben Merkoci.  Micromotors are a hot topic amongst researchers around the world, and this study is the first to apply micromotors to surface-based biosensing systems.

The investigation was built on the hypothesis that the transport of target molecules toward a sensing surface plays a critical role in the performance of biodetection systems, particularly of microarray immunoassays, which could be used for important applications such as DNA and cell analysis.  The ICN2 researchers performed their experiments with a microarray immunoassay to detect Apolipoprotein E, a molecule associated with Alzheimer’s disease.  They added micromotors and oxygen peroxide to samples to be analyzed.  Propelled by the oxygen bubbles released from peroxide, the micromotors spread throughout the solution and generated fluid motion that increased the interaction between the proteins in the sample and the analytical surface of the immunoassay.  Indeed, the researchers found that the use of artificial micromotors increased the sensitivity and accuracy of the microarray immunoassay.  They propose that this innovative strategy be extended to other applications in diagnostics, as well as to safety and security.

Article Reference:

Eden Morales-Narvaez, Maria Guix, Mariana Medina-Sanchez, Carmen C. Mayorga-Martinez and Arben Merkoci, Micromotor Enhanced Microarray Technology for Protein Detection, Small (Ahead of print). Article first published online: 14 MAR 2014. DOI: 10.1002/smll.201303068 http://onlinelibrary.wiley.com/doi/10.1002/smll.201303068/abstract