Instrumentation approaches to biological system assessment, guided MSC differentiation, and functional tissue engineering

Cashion, Avery Ted, IV

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March 21, 2019

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Cashion, Avery Ted, IV
- Affiliation: School of Medicine, UNC/NCSU Joint Department of Biomedical Engineering

Abstract

Instrumentation methods and tools are developed for electrical and mechanical stimulus/assessment of biological systems. In Chapter 1, a distributed control data acquisition system (DAQ) was developed and demonstrated in the application of measurement and analysis of dielectric relaxation sensing of bio-cultures. As a demonstrative example, a simple probe was constructed and used to measure absorption behavior of varying volumes of soybean oil. Extracted features of this calibration dataset were used to train a support vector machine (SVM). The SVM was then able to predict the known volumes of a separate specimen with approximately 98% accuracy. In Chapter 2, enabling bioreactor technologies were developed for the investigation of the effects of periodic strain on patches of self-organized rat myocardial tissue in-vitro using a novel voice coil actuator (VCA) system. The DAQ was purposed as a control board for the VCA mechanobioreactor network. The researcher can program strain protocols for individual bioreactors using a single user interface on a computer. Possible implementations of the described system include micro-newton twitch force measurement capability as well as the ability to generate stress-strain curves of engineered tissues. To examine the compatibility of the bioreactor with engineered tissue samples, a uniaxial 1Hz cyclic 10% tensile strain was applied to 2cm square tissue patches for 4 hours. A significant increase in contractile force was observed after the strain period. In Chapter 3, the VCA system was modified to enable research on the effects of periodic vibratory stimulus on human and porcine mesenchymal stem cells (MSCs). Multiple bioreactors within the incubator can be independently addressed. Once programmed, the embedded microprocessor and sensor system on each bioreactor execute the specified protocol independent of the computer. Sinusoidal stimuli were applied to culture plates in 1 minute intervals with a 15 minute rest following each, for a total of 15 hours per day for 10 days. Frequencies of 1 and 100Hz were applied to cultures of both human and porcine umbilical cord (UC)-derived MSCs. Staining and mRNA quantification indicated that 1 Hz stimulation resulted in a cartilage phenotype for both human and porcine MSCs; 100Hz stimulation resulted in bone phenotype.

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