Post-doc David Cottenden
Mechanical properties of sintered polymer composites.
David is studying Selective Laser Sintered (SLS) polymer composites
as part of a multinational, EU funded project with a budget of €4.4M. The long-term objective of the project is to develop materials and processes that enable SLS to be used effectively to manufacture small batches of high-quality, customised components for various markets. David uses both experimental and theoretical approaches to understand such materials’ mechanical behaviour, including micro- and nanoindentation, various types of microscopy, and analytical and computational modelling. Particular interests are in relating indentation and compression behaviour of particles and consolidated samples to each other and the consolidated structure. Such models should enable structure to be inferred from simple mechanical tests; mechanical properties to be predicted on the basis of base material properties and structure; and (importantly) the structural origins of shortcomings to be identified and addressed.
Oliver Hudson, PhD student
Novel wood-polymer composites for sustainable building
Oliver is working as part of a collaborative project with the Departments of
Chemistry and Architecture to develop novel wood composites for use as
sustainable, structural, building materials. The project has the objective
of the creation and utilisation of innovative timber impregnation
technologies that lead to low energy methods for improving the structural
properties of fast growing, porous woods while adding additional benefits
such as increased material utilization, reduced processing requirement,
reduced in-situ maintenance requirement and an ecologically efficient end of
life disposal. His work is currently focusing on accurately quantifying the
embedded energy differential across virgin, engineered and modified woods
that meet structural grades, the mechanical testing of UK grown species that
are impregnated in order to improve their structural properties and the
development of both modified and un-modified short rotation coppice (SRC)
Ching Theng Koh, PhD student
Fracture of Protein-based Materials
Ching Theng is working on multi-scale modeling of protein–particularly collagen–based materials with a particular emphasis on deformation and fracture. Fracture of collagenous tissues has two different types of relevancies within the context of medicine: firstly, fracture of connective tissues is associated with injury, as in the fracture of bones, rupture of knee ligaments, and cracking of cartilage and fibrocartilage in the knee joint; secondly, fracture of connective tissue membranes is a normal and required stage in a successful outcome concerning birth, where the fracture is colloquially referred to as the “breaking of waters”.
Khaow Tonsomboon, PhD student
Corneal Tissue Engineering
I am developing a human cornea analogue to be used for corneal transplantation because there is a severe shortage of good quality donor cornea, particularly for young patients. Hence, the aim of this project is to develop a novel scaffold, which imitates the entire structure and performs similar functions to the natural cornea. This bio-mimetic structure should support corneal regeneration and could be used as an alternative to the donor cornea. Not only does this corneal analogue overcome the shortage of donor corneas, the rejection of donor corneas due to immunological responses is also no longer a problem. This promising development would bring new hopes to fifteen millions visually impaired people worldwide.
Jenna Shapiro, PhD student
Stem Cell Niches and Hydrogels
Jenna is working on a collaborative project with the U.S. National Institutes of Health as part of the NIH-Cambridge Graduate Partnership Program, and is jointly mentored by Dr. Constantine Stratakis of the National Institute of Child Health and Human Development. Her project focuses on using hydrogels as scaffolds for creating an in vitro model for the cellular microenvironment. In particular, she will fabricate and characterize a number of hydrogel systems and determine mechanically and biologically relevant properties. Once a hydrogel system has been optimized, it will then be used to create an in vitro model of the cell-extracellular matrix interaction. Jenna is particularly interested in exploring the interaction between chemical and mechanical signaling in the cellular microenvironment, and will do so in the context of cyclic AMP and protein kinase A signaling and collagen production and deposition.
Tamaryn Shean, PhD student
Small-scale Mechanical Characterisation of Adhesive Systems
Tamaryn is working on analytical and experimental understanding of the complexities of viscoelastic (time-dependent) – adhesive interactions in synthetic and biological systems. Adhesion is a complicated physical phenomenon in which two or more bodies are connected by chemical or physical interactions. Time-dependance in materials is a regularly occurring phenomena, due to weak interactions. Synthetic adhesives are specialist thin film materials; this thin film geometry leads to difficulties when large-scale testing is the only technique employed for mechanical characterisation. Natural adhesive systems are both viscoelastic and adhesive employing structure and compliance to form optimised detachable and reusable systems. Due to the diversity in these systems there is a need for improved mechanical characterization techniques for understanding viscoelastic – adhesive materials, which presents an ideal opportunity for development of complex small-scale testing techniques (such as nanoindentation) and analysis methods.
Daniel Strange, PhD student
Spinal Disc Tissue Engineering
Daniel is developing a novel tissue engineering implant to be used for the
treatment of back pain. Back pain is often thought to arise because of the
degeneration of the intervertebral disc. Current treatments, such as
discectomy and spinal fusion, have been shown to reduce pain in the short
term but have questionable long term outcomes as they significantly alter
the biomechanical properties of the spinal segment. Tissue engineering is an
emerging field which aims to produce a functional tissue replacement that
encourages the body to regenerate tissue and heal itself. The aim of this
project is to develop a scaffold which mimics the structure and mechanical
properties of the intervertebral disc. It is hypothesized that because cells
have been shown to change their behaviour in response to mechanical load, a
scaffold with a physiologic structure will encourage cells to express
themselves in a manner relevant to their local stress state resulting in an
implant biomechanically similar to a healthy intervertebral disc.
Oliver Armitage, MPhil student
Oliver is working on the mineral-collagen interface as found in many natural materials including eggshell, articular cartilage and ACL – bone interfaces. This interface is characterised by a tri-phasic structure that provides a mechanicaly robust and biocompatible interface between natural hard and soft materials. In order to replicate the mineral collage interface Oliver is using a modified automated Alternate Soaking Process to induce heterogeneous nucleation of a calcium carbonate-gelatin composite on collagenous membranes. This addition of gelatin to the mineral replicates the organic component of many biominerals. In addition, his work aims to replicate the mechanically advantageous microstructure of avain eggshell that is achieved by spatial control over the nucleation sites of crystals by using analgous protein factors to those found during mineralisation in the avian shell gland.
Mechanics of Functionally-graded Biomineralized Composites
- Helen Brawn, Mechanics of Hydrogels
- Tess Catherwood, Mechanics of bone-interface implants
- Sarah Greasley, Mechanics of Eggshells
- Mark Varley, Engineering Analysis of Immunological Assays
- Tom Wagner, Mechanics of Composite Hydrogels