Start
Feb 08, 2018 - 17:00
End
Feb 08, 2018 - 18:00
Venue
Rm. No. 118 Ground floor Chemical Engg. Dept.
Event Type
Speaker
Dr. Jothirmayanantham Pichaandi Fluidigm Canada
Title
Nanoparticle- Antibody Conjugates as High Sensitive Reagents for Mass Cytometry
Abstract: Mass cytometry (MC) is a recently developed single cell analysis technique to identify several cellular biomarkers simultaneously. This technique combines the power of flow cytometric injection of cells with an inductively coupled mass spectrometer (ICP-MS) coupled with time of flight detection. MC employs metal isotopes to tag the antibodies (Abs) and these metal isotopes have a unique mass that can be detected and quantified by mass spectrometry. Flow cytometry the most commonly used single cell analysis technique to study cellular biomarkers can measure only up to 8 to 10 cellular biomarkers simultaneously. Beyond the detection of 8 to 10 biomarkers the technique is limited by the luminescence spectral overlap of the dyes and the quantum dots used to tag the Abs which identifies the specific biomarker on the surface or inside the cell. On the other hand the number of biomarkers identified using MC depends only on the number of different metal isotopes that can be used to tag the Abs. As with all techniques there is certain limitation to this technique as well. When compared to flow cytometry this technique suffers from poor sensitivity due to the fact the current reagents metal chelating polymers with 40 to 50 metal atoms per polymer chain cannot generate enough signal to identify proteins which are present in very low copy numbers in cells. MC is a quantitative technique and the fact the signal intensity increases linearly with the number of metal atoms tagged to each Ab my research is primarily involved in developing antibody conjugates with more metal tags per Ab. To achieve this goal I am working on developing reagents based on nanoparticles to enhance the detection sensitivity of low copy markers by one or two orders of magnitude than current reagents. I will elucidate the various criteria which have to be satisfied when employing NPs as high sensitive reagents. The synthesis nucleation and growth kinetics of the various NPs will be discussed in detail. Subsequently I will talk about two surface modification process to make the NPs biocompatible and their effect on the non-specific interaction of the NPs with various cells lines. The various conjugation chemistries to couple the NPs to Abs will be explored and finally finish with examples of mass cytometry single cell measurements where the NPs exhibit higher signal for various biomarkers when compared to current metal chelating polymer reagents.Bio: Jothir Pichaandi obtained his B.Tech in 2003 from Laxminarayan Institute of Technology Nagpur University in Chemical Technology with specialization in polymers. Thereafter he moved to Institute of Chemical Technology (ICT) formerly UDCT Mumbai to obtain his M.Tech degree in Polymer Engineering and Science (2005). He started his PhD at the University of Victoria in 2006 under the supervision of Prof. Frank C. J. M. van Veggel and graduated in 2012. During his PhD he worked on developing luminescent nanoparticles and its application as luminescent biolabels for deep tissue imaging. After a short stint as post doctorate with his PhD thesis advisor he joined Prof. Mitchell A. Winnik as a post doctorate in Sep 2013 and stayed there till May 2017. In Prof. Winnik’s group he worked on developing lanthanide based nanoparticles and polyamine based polymers as reagents for single cell assays using Mass Cytometry. This work was carried out as a collaboration between University of Toronto and Fluidigm Canada. Currently he is working in Fluidigm Canada as a Scientist to commercialize his post doctorate work.