Bioactive nanoparticle incorporation into inorganic/organic hybrids
File(s)
Author(s)
Li, Zhenlun
Type
Thesis
Abstract
Mesoporous silica nanoparticles have a great therapeutic potential as they can deliver active
ions and they also have been made to nanocomposites with polymers for bone regeneration.
Hybrids are co-networks of inorganic and organic components that can be produced with
interconnected pores, matching mechanical properties to the host tissue and controlled
biodegradability. Both silica nanoparticles and hybrids can be made from the sol–gel process.
Calcium incorporated mesoporous silica nanoparticles (MCE) have been developed as a
bioactive cation carrier. In this thesis, a PTHF/PCL/MCE/SiO2 nano-hybrid network was
achieved. For the first time, (3-Glycidyloxypropyl)trimethoxysilane (GPTMS) functionalized
MCEs were incorporated into a hybrid and covalently bonded to the silicate network. Dense
calcium containing silica nanoparticles were found not to be suitable for GPTMS grafting
because of the low concentration of hydroxyl groups on the particle surface. Calcium
incorporated mesoporous silica nanoparticles proved themselves to be a better choice for the
functionalization as they had larger surface area and higher -OH surface density. In a Tris
buffer dissolution study, the existence of covalent bonds between MCEs and the polymer
network made them to release calcium at a slightly slower rate compared with
unfunctionalized samples. In SBF dissolution, only a small amount of HCA formation was
captured on specific samples after 3 weeks. This suggested the amount of calcium
incorporated into particles were too low. Because of the suspected release of remained
BF3OEt2, which caused a significant pH drop in solution, samples failed to pass cytotoxicity
tests unless they were washed in water for 24 h prior to the test. Finally, porous scaffolds
were fabricated by using 3D extrusion printing and the ink rheology profile showed a shear
thinning behaviour.
The concept of using nanoparticles as a bioactive cation carrier covalently bonded to the
hybrid network was proven to be feasible. This nano-hybrid system also has potential for
incorporating other cations for different applications, such as lithium for cartilage and
strontium for bone regeneration.
ions and they also have been made to nanocomposites with polymers for bone regeneration.
Hybrids are co-networks of inorganic and organic components that can be produced with
interconnected pores, matching mechanical properties to the host tissue and controlled
biodegradability. Both silica nanoparticles and hybrids can be made from the sol–gel process.
Calcium incorporated mesoporous silica nanoparticles (MCE) have been developed as a
bioactive cation carrier. In this thesis, a PTHF/PCL/MCE/SiO2 nano-hybrid network was
achieved. For the first time, (3-Glycidyloxypropyl)trimethoxysilane (GPTMS) functionalized
MCEs were incorporated into a hybrid and covalently bonded to the silicate network. Dense
calcium containing silica nanoparticles were found not to be suitable for GPTMS grafting
because of the low concentration of hydroxyl groups on the particle surface. Calcium
incorporated mesoporous silica nanoparticles proved themselves to be a better choice for the
functionalization as they had larger surface area and higher -OH surface density. In a Tris
buffer dissolution study, the existence of covalent bonds between MCEs and the polymer
network made them to release calcium at a slightly slower rate compared with
unfunctionalized samples. In SBF dissolution, only a small amount of HCA formation was
captured on specific samples after 3 weeks. This suggested the amount of calcium
incorporated into particles were too low. Because of the suspected release of remained
BF3OEt2, which caused a significant pH drop in solution, samples failed to pass cytotoxicity
tests unless they were washed in water for 24 h prior to the test. Finally, porous scaffolds
were fabricated by using 3D extrusion printing and the ink rheology profile showed a shear
thinning behaviour.
The concept of using nanoparticles as a bioactive cation carrier covalently bonded to the
hybrid network was proven to be feasible. This nano-hybrid system also has potential for
incorporating other cations for different applications, such as lithium for cartilage and
strontium for bone regeneration.
Version
Open Access
Date Issued
2018-10
Date Awarded
2019-02
Copyright Statement
Creative Commons Attribution NonCommercial Licence
License URL
Advisor
Jones, Julian R.
Saiz Gutierrez, Eduardo
Publisher Department
Materials
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)