Searching for the Single Cell

Single Cell Analytics Center

Researchers in the Single Cell Analytics Center (SCAC) work with industry and academic partners on the Signal Ion Emission Reactive Release Amplification (SIERRA) platform for rare cell analysis.

In 2018, the Single Cell Analytics Center (SCAC) advanced the SIERRA platform significantly towards commercialization. Currently, it can detect fewer than 30 cells in a whole blood sample by size-exclusion filtration, microfluidic sample handling and mass spectrometry. The team continued to develop a method for the non-destructive enumeration of rare cells at a sensitivity of 20 cells from whole blood samples with same-sample RNA analysis.

This means they were able to filter out and count as few as 20 cells from a blood sample without any cell damage, followed by molecular tests. A manuscript describing this progress has been accepted for publication in Analytical Chemistry.

funding for commercialization

Grant applications proposing the use of SIERRA technology with new antibiotics, affinity agents and lipidomics methods for the analysis of drug resistance in urinary tract infections were completed and are ready for submission in early 2019.

  • This work seeks to increase the specificity and sensitivity of bacterial cell targeting to enable the use of SIERRA technology without a bacterial cell culture step.
  • Such funding may enable rare cell analysis in military, public health, chronic disease and food safety applications.

How we’re increasing cell-detection effectiveness

Michael Pugia, Ph.D.

Michael Pugia, Ph.D., Director, Single Cell Analytics Center

A working laboratory format for the SIERRA platform, in which nanoparticles are combined with standard 96-well microtiter plates, was completed to test its effectiveness. Manufacturing procedures are on track to provide a routine supply of reagents for analysis.

This continuous improvement will allow the targeting and detection of an even lower number of cells. New nanoparticle chemistries have also been identified which may improve assay sensitivity to allow the detection of a single cell.

Perfecting the rare-cell analyzer

Collaborator: Purdue University

Working with collaborators from Purdue University’s School of Mechanical Engineering, the SCAC constructed the first “breadboards” (a construction base for prototyping) of the microfluidic interface for a point-of-care Rare-Cell Analyzer that is compatible with SIERRA and other detection technologies.

SCAC postdoctoral trainees in bioanalytics identified and selected areas for improvement and generated advanced technology data under the supervision of staff scientist Dr. Zane Baird. Related to this work, Dr. Baird was part of a team that was awarded $30,000 by Purdue for research using mass spectrometry to identify antibiotic-resistant bacteria in recalcitrant urinary tract infections.

The SEIRRA platform may ultimately achieve the diagnosis of infections and other diseases from a single cell. This may significantly reduce waiting times and costs for patients, especially for the identification of bacterial infections. 

SCAC postdocs and scientists make important advances

Three SCAC postdoctoral fellows also made significant advances with the SIERRA platform.

  • Dr. Daniel Debroy integrated new particle-capture features into the breadboard design in collaboration with Purdue.
  • Dr. Tiyash Bose integrated rapid enzymatic electrochemistry detection into the breadboard and nanoparticle design in collaboration with Indiana University.
  • Dr. Marco Tjioe designed a set of 10 multiplexed mass labels and demonstrated simultaneous quantitation over a dynamic range spanning three orders of magnitude.

This work will facilitate the simultaneous detection or targeting of multiple cell types in the same sample, such as different species of bacteria, which may save time and resources.

Overall, these enhancements are expected to improve cell detection sensitivity and greatly increase the applicability of SIERRA technology in the life sciences ecosystem and in the clinic.

Demonstrating the SIERRA platform's effectiveness

Collaborators: Purdue, IU and University of Notre Dame

The SCAC assay team under the direction of Senior Staff Scientist Dr. Zehui Cao demonstrated the utility of SIERRA technology by confirming the detection of bacterial cells in any sample media. The team successfully used the immunoassay and genetic assay platform to screen for bacteria and avoid antibiotic resistance in collaboration with Purdue, IU and University of Notre Dame.

Dr. Dylan Frabutt, a bioanalytical postdoctoral trainee, developed screening methods to select affinity agents for a multiplexed bacterial panel comprising several bacterial pathogens. In collaboration with Purdue, he developed microbiological tools by using lipidomics and other methods to measure antibiotic efficacy.

Lipidomics is the large-scale study of cell wall lipids (fatty acids) and this work will improve the SIERRA platform’s ability to detect microbes as a further development along the path toward commercialization.

Dylan Frabutt, Daniel Debroy and Marco Tjioe

SCAC Postdoctoral Fellows Dylan Frabutt, Daniel Debroy and Marco Tjioe use fluorescence activated cell sorting (FACS), a method used to characterize and sort cell populations by using fluorescent markers.

Single cell analysis performed by FACS enables researchers at the IBRI to design and optimize alternative cell detection techniques that can be adapted to point-of-care diagnostic devices. 

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