Student projects

Fabrication of in vitro cerebral aneurysms models

Project: Not available (Spring 2020)

Type of project: Semester project 

Description

Photopolymerizable hydrogels might be a promising solution to treat cerebral aneurysms. In order to accurately characterize the properties of hydrogels, in vitro models need to be fabricated. A method combining 3D printing of PVA molds and PDMS casting has been developed to fabricate simple aneurysms models.

Aim

The objective of this project is to develop more complex geometries of aneurysms models based on the previously mentioned technique.

Contact the following person for details about the project: [email protected]

3D bioprinting of hydrogels for anisotropic load-bearing implants

Project: Available (Spring 2020)

Type of project: Master project

Context

Due to their high water content and soft consistency, hydrogels are suitable biomaterials for a wide range of biomedical applications such as drug delivery, tissue engineering or tissue repair [1]. One particular interest is to replace load-bearing tissues such as articular cartilage, meniscus or intervertebral disc. Although their high water content between 60% and 95%, those tissues show extraordinary mechanical properties [2].

Nevertheless, the processing of a hydrogel that could mimic load-bearing tissues behavior is particularly challenging because of the highly hierarchical microstructure of isotropic and anisotropic regions in natural tissues.

A recent technic used granular gels as a medium for additive manufacturing. It allows printing complex structures such as blood vessels because the needle can freely deposit the printed material in the whole volume of the granular medium [3].

Goal

Design, develop and characterize 3D bioprinted anisotropic hydrogels.

Tasks

  • 3D bioprinting (e.g. G-code, processing parameters)
  • Bioink fabrication and characterization (e.g. rheology)
  • 3D printed hydrogel characterization (e.g. mechanical testing, 3D digital image correlation)

References

[1] A. S. Hoffman, « Hydrogels for biomedical applications », Adv. Drug Deliv. Rev., vol. 64, Supplement, p. 18‑23, 2012.

[2] L. T. Brody, « Knee osteoarthritis: Clinical connections to articular cartilage structure and function », Phys. Ther. Sport, vol. 16, no 4, p. 301‑316, 2015.

[3] C. S. O’Bryan et al., « Self-assembled micro-organogels for 3D printing silicone structures », Sci. Adv., vol. 3, no 5, p. e1602800, 2017.

This project will be supervised by Celine Wyss and under the direction of Dr. Pierre-Etienne Bourban and Prof. Dominique Pioletti. The student will be in the Laboratory for Processing of Advanced Composites and the Laboratory of Biomechanical Orthopedics.

Contact the following person for details about the project: [email protected]


How cell-matrix interaction is modulated by incorporated ECM-mimetic elements into pHEMA hydrogels?

Project: Available

Type of project: Master project

Requirement: Cell culture

Background: in microscopy and PCR analysis is a plus.

Description: Careful design of biomaterials properties, cell-scaffold interaction and mechanical stimulation are required to biophysically guide chondrocytes differentiation. One mechanism by which cells may sense the surrounding microenvironment is through their integrin interaction with anchored ligands within the extra cellular matrix (ECM). ECM-mimetic functionalization of synthetic hydrogels can therefore be adopted to enhance integrin mediated mechano-sensing. It is well known that Arginine, Glycine and Aspartate (RGD) sequence in ECM proteins such as fibronectin provides attachment sites for integrin receptors. However, the role of ECM-mimetic elements in chondrogenic differentiation of cells embedded in hydrogels could be debatable according to the current literature. The aim of this project is to evaluate chondro-progenitor cells behavior in response to incorporation of ECM-mimetic elements into pHEMA hydrogels in presence and absence of dynamic loading.

Contact the following person for details about the project: [email protected]