Session: ASME Undergraduate Student Design Expo

Paper Number: 175744

Laser-Initiated Adhesive Separation of Cancer Cells 

Cancer related deaths are the second leading cause of death behind cardiovascular disease in the United States. Metastatic cancer represents a major contributor to cancer related deaths. There are currently no universal biomarkers that can be used to identify and diagnose metastatic cells. Therefore, an approach that utilizes the phenotypic properties of metastatic cells for identification represents a viable approach for diagnostics. One such phenotypic property is adhesion strength. Metastatic potential has been linked to a lower adhesion strength than non-metastatic cells. Adhesion strength can be assessed through various techniques including shear flow assays, atomic force microscopy, and counting methods. Studies have utilized shear flow assays to attempt to sort cancerous cells based on metastatic potential. However, this work explores tensile loading to measure adhesion strength in cancerous cells. 

Our technique utilizes laser-induced stress waves to eject cells with a comparatively lower adhesion strength from a culture surface. A neodymium-doped yttrium aluminum garnet (Nd:YAG) laser is used to generate a single laser pulse which impinges upon the backside of a substrate assembly. The substrate assembly is composed of an absorbing layer and confining layer on a glass slide attached to a petri dish. Once a laser pulse reaches the absorbing layer, the laser pulse converts to a compressive mechanical wave that propagates towards the culture surface. The compressive wave reflects off the free surface and loads the cell-surface interface in tension. Laser fluence (energy/area) is varied to control the magnitude of the generated tensile stress wave. The applied high-stress tensile wave loading induces spallation of low adhesion cells. The ejected biological matter is collected via a receiving substrate to record and measure whether ejected cells are viable post spallation. The receiving substrate utilizes a glass disk coated in a nontoxic, biocompatible material (such as Matrigel or Polydimethylsiloxane) to encourage potential culture of captured cells and biomaterial. Optical microscopy is used to confirm ejection of cells from the culture surface and investigate the receiving substrate for intact cells. Three pairs of cancerous tissue cell lines (tongue, breast, endometrial) are tested. Each pair features a low and high metastatic potential cell line. The tongue cell lines are Cal-27 (low) and SCC-25 (high), the breast cell lines are MCF-7 (low) and MDA-MB-231 (high) and the endometrial cell lines are Ishikawa (low) and KLE (high). Our prior work involving shear flow assays has shown that these cell line pairs have significant differences in adhesion strength between the low and high metastatic potential lines.

 

Initial testing demonstrated successful ejection and capture of intact cells for the first time. The goal of this work is to develop a technique for early detection of cells undergoing an epithelial to mesenchymal transition without the use of magnetic particles or fluorescent labels. Current diagnostic techniques require the use of these devices to separate cancer cells. Thus, this technology enables the separation and sorting of cells based on differences in adhesion, providing a powerful tool for studying cancer cell metastasis. 

 

Presenting Author: Austin Stallings University of Kentucky

Presenting Author Biography: At the Grady Lab, Austin works on the LASSo project (Laser-initiated Adhesive Separation and Sorting), a cutting-edge study that uses high-power lasers to detach cancer cells grown on specialized substrates. By measuring adhesion strength and evaluating cell viability, Austin contributes to research that could advance our understanding of cancer behavior and potential detection methods.

Austin will be graduating this December 2025 and is originally from Owensboro, Kentucky. Outside of the lab, Austin is preparing for the next step in his career and is actively seeking full time opportunities in R&D/testing and mechanical design. His passion for problem-solving and hands-on innovation drives him to pursue a future where engineering meets impactful real-world solutions.
I am proud to spotlight Austin’s hard work and dedication to both engineering and biomedical research!

Authors:

Austin Stallings University of Kentucky
Brandon Quigley University of Kentucky
Lauren Mehanna Centre College
Joy Resig University of Kentucky
Martha E. Grady University of Kentucky