The goal of my project is to quantify and measure the adhesion strength of biological cells to various types of substrates such as titanium, cobalt chromium, and polystyrene. Cellular adhesion strength is an important factor in many biomedical engineering applications, such orthopedic implants design, dental and prosthodontics manufacturing, and also in tissue engineering applications to name a few.

Current methods used to measure cell adhesion strength include radial flow techniques, micro-cantilever beam measurements, and jet impingement based methods, however, results derived from these methods have been inconsistent.

The advantage of the Laser Spallation Technique (LST) (see image below) used in our lab is that interfacial stress measurements can be quantified one-dimensionally, unlike existing techniques which must consider multi-axial stress-state. Also, cellular interface strength can be determined without the need to consider inexact variables such as Young’s modulus, Shear modulus, etc., which other methods are dependent upon.

Laser Spallation Technique for measuring cellular interface strength. 1) Laser pulse passes through convex lens and enters disk holder with constraining material (water in this case) and hits the backside of titanium disk, 2) nanosecond stress-wave in substrate is formed, 3) cell grow on opposite face are ejected.

Currently, our research group is seeking to measure interface strengths between chondrocytes and titanium, fibroblast and polystyrene, and bone tissue and several other kinds of substrates. This project is in collaboration with Prof. Ben Wu’s lab in Biomedical Engineering IDP, Prof. Takahiro Ogawa’s lab in the Weintraub center for reconstructive biotechnology, and Prof. Theodore Hahn’s lab in the VA hospital research center.