The external mechanical load will firstly cause the mechanical deformation of neurons, and then, when this deformation reaches to a critical point (threshold), it will initiate the chemical/biological response. The chemical/biological response can cause the neuronal function loss-neuronal injury. This process is considered to be the mechanism of the mild traumatic brain injury (mTBI) at the cellular level. Understanding the relationship between the neuronal mechanical response and their biological responses is the first important step to understand the mechanism of mTBI.
Dr. Guoxin Cao
Cultured SHSY5 neurons, (a) Fluorescence optical image of the neuron monolayer, (b) Optical image of neuron monolayer; (c) Fluorescence optical image of the isolated neurons.
(a) Customized cell uniaxial stretcher, (b) PDMS membrane used as the substrate of cell culturing.
(a) Flexcell 5000 cell stretching system, (b) Loading station, (C)Cell culturing dish for equibiaxial stretching.
Raman Analysis of Neuron Injury
Raman spectroscopy can provide the structural and quantitative information of cell by directly measuring the vibration characteristics of the chemical bonds of the molecules. Each characteristic vibration frequency is corresponding to a specific molecular functional group (protein) inside cell, and the relative intensity of that spectral band can be used to reflect the relative concentration of that particular functional group. Thus, by tracking the Raman spectra history, the transformation of a biochemical reaction can be dynamically monitored.
In our test, CRS will be used to observe the response of some isolated neurons (selected from the patterned neurons under the different deformation levels) immediately and every 8hours after neuron stretching. By measuring the temporal changes of Raman spectra of isolated deformed cells, we demonstrate a molecular-level assessment of neuron injury in real time without introducing the exogenous reagents.
Build the microscale mechanical model to correlate the mechanical deformation of neurons and their nonlethal injury. The mechanical deformation of uniaxial/equibiaxial stretching is applied on the In Vitro cell model; the cell injury.
Understand the neuron mechanical response to the external load by matching the measured deformation field (using Fluorescence microscopy) and the simulated deformation field based on 3D neuronal geometry (using Finite element simulations).
Measure the mechanical property of neurons using Atomic Force Microscopy (AFM).