A New Mobile Device to Measure Bio-particles Rapidly
- Published: Monday, 05 February 2018 08:00
As far as health related issues, new findings and solutions of health related is-sues are popping up quicker more than ever, thanks a lot to new technologies and instruments.
For detecting small molecules, there are different kinds of Mass Spectrometry (MS) devices, owning a MS device can help scientists find out the unknowns of many small substances, owning a MS device also requires quite a monetary investment. Recently, there has been an increasing interest in using a mass spectrometer to measure the masses of micro-particles, be it polymeric particles, human cells, bacteria, or viruses.
However, there is still a vacant spot as far as what the commercially available MS devices can do. Simply put, cells, virus, micro and nanoparticles are all too large to be measured rapidly by currently available MS devices, yet too small to be measured by any other means.
Dr. Winston Chen and his colleagues in Academia Sinica have dedicated a major research effort in finding better solutions to MS technology. Their latest design of an Electrospray Ionization Quadruple Ion Trap Mass Spectrometer (ESI QIT MS) device has successfully conquered many prior obstacles, and this new device not only can measure a large number of bio-particles in a much shorter time frame, it also requires much less preparation work with minimum tampering of the sample object.
In his lab, they have always aimed to build a system which can analyze all types of particles. In the recently published article in Analyticl Chemistry, they have successfully measured different sizes of MCF-7 breast cancer cells (8 to 15 micrometers).
According to Dr. Abdil Ozdemir, first author of this study, in comparison with other laser-based methods, the sample preparation is much simpler and takes less time. This method can easily provide information for the measurement of particles in solution without drying. Previously, they used laser induced acous-tic desorption (LIAD) to push the object into the MS chamber. LIAD was also developed by Dr. Chen and his colleagues several years ago. For LIAD, they need to dry the object, all these made that technology exciting but too expen-sive and cumbersome to do in-situ real-time analysis. ESI QIT MS can also be used to measure particle mass distributions for a powder sample with practically no need of any sample preparation.
In this new design, they replaced LIAD by pushing particles into the MS de-vice in their original form, whether as dry powders, chemicals in tiny droplets, or cells in water, directly into the chamber to weigh. This new system does not need the application of different voltages to the interface lenses. The only volt-ages applied to the whole system were the DC voltage and RF trapping voltage to the ESI source and ion trap respectively. A simple suction pump similar to the one in a vacuum cleaner is enough to reduce the pressure for the operation of this instrument, and it is not necessary to create high vacuum status which nearly all mass spectrometers need, therefore, it's possible to make the device light weight, mobile, and low cost to build.
Dr. Chen and his colleagues are quite thrilled about the new development, their vision has finally come to a reality. They have lots of possible applications in mind for this new device down the road. For example, it has the potential to be used to determine the type of strain of flu virus by measuring virus mass during the flu season. Similarly, it can be applied to the identification of different bac-teria and cells. PM2.5 particles that exist in our environment can be trapped and measured on the spot and differentiated according to their mass distributions for further analysis.
In Dr. Chen's pursuit, he has an even bigger picture laid out, their lab will keep on working for achieving an ultimate goal, step by step, they would like to first categorize unknown particles by sizes, then, to further break down each type and do more detailed chemical analysis for each cell and each mi-cro/nano-particle.
In order to find bio markers of cancer cells, it is possible to add several anti-bodies simultaneously to target cancer cells and shoot into the MS device to observe the mass changes right away. It has the potential to do both qualitative and quantitative analysis of cancer biomarkers. They are actively working on developing a MS cell sorter that can be simpler and cheaper than current flow cytometry device. By quickly identifying biomarkers of cancer cells, it is possi-ble to characterize each tumor sample, a step closer to provide information for personalized cancer therapeutics.
The contributors of this research are: Abdil Ozdemir, Jung-Lee Lin, Mustafa Gulfen, Szu-Hsueh Lai, Chun-Jen Hsiao, Nelson G. Chen, and Chung-Hsuan Chen, The article of this research study can be read online at: http://pubs.acs.org/doi/10.1021/acs.analchem.7b02937