Texas A&M innovates cellphone-based Raman spectrometer…

17 Jul 2024

…while Vanderbilt develops laser-based method for “liquid biopsies”.

Identification and detection of drugs, chemicals and biological molecules invisible to the human eye can be made possible through the combined technology of a cellphone camera and a Raman spectrometer — described by its inventors as “a powerful laser chemical analysis method”.

Dr. Peter Rentzepis, a professor in the Department of Electrical and Computer Engineering at Texas A&M University, holds a patent for a hand-held cellphone-based Raman spectrometer system. His invention allows a user to make non-invasive identifications of potentially harmful materials in the field, especially in remote areas.

This Raman spectrometer system integrates lenses, a diode laser and a diffraction grating in combination with a camera from a cellphone to record the Raman spectrum. Peaks in the spectrum provide detailed data about the chemical composition and molecular structure of a substance.

To use the device, a cellphone is placed behind the transmission grating with the camera facing the grating, ready to record the Raman spectrum. A laser directs a beam into a sample, such as a bacterium, on a slide. The camera records the spectrum, and when paired with an appropriate cellphone application/database, this handheld instrument enables rapid materials identification.

Conventional Raman spectrometers cost up to thousands of dollars, but Rentzepis’ invention can be made at a lower cost and can identify materials at a significantly quicker speed.

Co-inventors are former graduate students Dr. Dinesh Dhankhar, a system engineer at Thermo Fisher Scientific, and Anushka Nagpal, a process engineer at Intel. Funding for this research is administered by Texas A&M Engineering Experiment Station.

Vanderbilt develops laser method for ‘liquid biopsies’

Researchers from the School of Medicine Basic Sciences at Vanderbilt University, Nashville, TN, have developed a novel laser-based analytical tool that could enable “liquid biopsies” in place of conventional biopsies for certain patients or diseases.

The tool, called EV Fingerprinting, was the culmination of the dissertation work of Ariana von Lersner, a former graduate student and current postdoctoral scholar in the laboratory of Alissa Weaver, Cornelius Vanderbilt Professor of Cell and Developmental Biology. The work is described in ACS Nano.

The “EV” stands for extracellular vesicles, which are membrane-bound particles that contain biologically active contents that contribute to cell-cell communication in health and disease. The past two decades have seen research into EVs increase significantly; they have now been found to have roles in endocrine processes, immune responses, and even cancer progression.

“Fingerprinting allows us to characterize EVs with minimal sample preparation in a high-throughput manner, and helps to better classify the types of vesicles in the sample,” von Lersner said.

Flow cytometry

The technique involves isolating EVs from the rest of the cellular content in a sample, labeling them with a fluorescent lipophilic dye that intercalates into the EVs’ lipid bilayer, and running them through a flow cytometer, which directs a laser at a sample and then collects information based on how the light is refracted or emitted.

The collected information is compiled into a “fingerprint” that can be used to perform quantitative analyses of distinct EV populations and determine how they are altered by experimental manipulation, molecular perturbation, or disease state.

“EV Fingerprinting is furthering the development of liquid biopsies in which the EVs can be used as biomarkers for diseases such as cancers or neurological disorders,” von Lersner said.