MARTEENI raw data

Published: 27-02-2021| Version 1 | DOI: 10.17632/4s45ntxhw3.1
Contributor:
Mary Kasper

Description

Files include raw measured data. Processed sample data can be found at http://dx.doi.org/10.17632/ktg5fp9gzn.1

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Stress-relaxation measurements of templated and non-templated hydrogels were obtained via non-destructive bulk indentation testing using a Bruker BioSoft In Situ Indenter. Tests were performed by indenting 6.5% of the total sample height at a rate of 20 µm/s. The probe was held at the maximum indent depth to obtain stress relaxation data; hold times varied between 10-30 s to allow samples to reach a quasi-static state. All tests were performed with a 3-mm-diameter spherical glass tip. Samples were kept hydrated and tested without submersion. Three locations were tested per sample, with each experimental group containing six samples (n=6). As described by Stewart et al. (2017), the Hertz contact model was used to obtain the transient modulus from force-displacement data, where the relaxation data were fit to the standard linear solid model to obtain the rate-dependent instantaneous modulus and the steady-state modulus. In vitro and in vivo analyses were performed using Zen Pro Image Analysis software. For in vitro analyses, the number of cells per depth was determined by taking the sum of all DAPI-stained pixels per z-stack and dividing by 100 pixels, which was determined to be the average nuclei size. In vivo analyses, average axon density was determined by taking the total axon count of an ROI divided by the ROI area (mm2). To derive the average axon diameter, axons were assumed to be circular in cross-section, where average diameter (d) was calculated from the average axon area (A) value (A = πr 2, where r = d/2). Collagen I, laminin, and Schwann cell average intensity were calculated from the “Mean Value Intensity” Zen software functions. Lastly, foreign-body-capsule thickness around the polyimide threads was measured from the outer edge of each thread to the outer edge of the fibrous capsule. Reported capsule measurements were averaged from four respective directions.