Mechanical Characterization of Silk Scaffolds

Silk scaffolds

Scaffolds are used in tissue engineering in order to promote cell migration, transport nutrients and foster tissue ingrowth. Silk scaffolds are known for its biocompatibility, biodegradability and impressive mechanical properties. This natural polymer serves as a suitable biomaterial in the field of bone regeneration. An important aspect that is considered by researchers is choosing a scaffold that is biomechanically optimal for placement into a bone defect. The scaffold must resemble the mechanical properties of the native bone in order to ensure that the scaffold can endure native stresses and to avoid stress shielding.

Aim of the study

The aim of this study was to develop a numerical relationship between the material properties and effective Young's Modulus of silk based scaffolds using a microCT approach. The study involves a sample of 10 silk scaffolds, formed using a salt leaching method to create scaffolds of various pore sizes.

MicroCT scan of silk scaffold

Segmentation in ScanIP

Smoothed mesh model 90x90x90 Slices = 3240x3240x3240 µm

Scanning and model generation in ScanIP and ⁺ScanFE

• Scaffold Type: 8 w/v% Silk Fibroin Concentration and 760±30µm Pore Size
• Shape: Cylindrical
• Dimensions: Length = 0.10m and Diameter = 0.012m
• Image Slice Thickness: 0.036mm

The scaffolds were imaged using microCT technology to obtain images that serve as the raw data for 3D reconstruction of the scaffolds. With the use of Simpleware ScanIP and ⁺ScanFE, accurate three dimensional models of the scaffolds were built, furthermore high quality meshes were generated from the 3D datasets.

FE Analysis in Ansys

Displacements and stress solutions

The meshed models were then imported into Ansys for mechanical modeling. A compressive load at z = zmax and boundary conditions at z = 0 were applied. The specific correlations between material properties (Young's Modulus) and effective measured and predicted stiffness of silk scaffolds helps highlight the important characteristics of a biomechanical optimal scaffold.

Customer Testimonial

"Simpleware is an exceptional image reconstruction and finite element meshing software that is wonderfully easy to use for biomedical engineering applications. Within a matter of minutes I was able to convert my micro-CT data into an accurate three dimensional CAD model, as well as a volumetric mesh in ⁺ScanFE. The time saved in developing these models quickly and efficiently is invaluable." - Dhyan Sundaresh

Publication

Sundaresh, D., Saigal, A., 2007. A Micro-CT Based Mechanical Characterization of Silk Scaffolds. Thesis (Master of Science), Tufts University.