Novel silane modified silica based inks for 3D bio-printing of breast tissue

Abstract

Background: Mesoporous silica nanoparticles (MSNPs) can be used in tissue engineering therapies where they function as a breast cancer therapeutic agent. The addition of particles can affect physical properties of the bulk tissue scaffold as well as carrying biomolecules. This offers the possibility to make tissue scaffolds which maintain morphology in vivo. Aims and Objectives: Aim: To develop, characterise drug releasing MSNPs and to synthesise GelMa hydrogels for application in breast tissue following mastectomy. Objectives: To fabricate and characterise the MSNPs (size, porosity, shape and zeta potential). To determine the effects of MSNPs into gelatin methacrylate, using rheology. Methods: The MSNPs were synthesised using a modified Stober sol-gel method, employing cetyltrimethylammonium bromide as a surfactant and tetraethyl orthosilicate as precursor, resulting in MCM 41 type nanoparticles. After characterisation, functionalisation was performed by reacting with 3-methacryloxypropyltrimethoxysilane and (3-methacrylamidopropyl) triethoxysilane. The gelatin methacrylate was synthesised using a one pot synthesis. After, both the functionalised and unfunctionalised nanoparticles were incorporated into the hydrogel. Cell culture was performed using 3T3 mouse fibroblast cells and were encapsulated or seeded on the gelatin methacrylate. Results: The Transmission electron microscopy analysis indicated that the average size of the MSNPs was just over 100 nm. The size and zeta analysis support this, whilst also showing a high mV value of -28 indicating good stability. The Brunauer Emmett Teller analysis exhibits isotherm properties that a mesoporous material exhibits. It was also observed that gelatin methacrylate showed comparable properties to a hydrogel. Cells also bound and proliferated on the gel if the gels were less than 5 mm thick. Conclusion: Investigations have shown that MSNPs change after functionalisation with both the hydrophobic and hydrophilic silane. Similarly, cells could be grown in gelatin methacrylate if there was sufficient oxygen and supplement saturation.

Date of Award	3 Jan 2018
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Brian Derby (Supervisor) & Olga Tsigkou (Supervisor)