The future of medicine

Materials World magazine
1 Mar 2014

Biomaterials science is at the forefront of medical innovation, as the fields of nanotechnology, medicine and materials science increasingly converge. Chris Wright, Executive Member of the Centre for NanoHealth at Swansea University, reviews the current state of affairs.  

The pace of advancements in the field of biomaterials owes a good deal to the legacy of developments within the field of nanotechnology, particularly in established methods to fabricate, modify and characterise biomaterials and bioprocesses at previously impossible scales. In addition, there are exciting developments in the fields of tissue engineering and cell therapies. Biomaterials research will need to maintain its momentum in order to fully realise the potential of regenerative medicine. Examples of notable recent research include the construction of living webs and tissue through the electrospinning of cells within a biodegradable polymer scaffold, the bioprinting of cells for tissue, and the use of nanotopographical patterns on biomedical plastic to differentiate bone cells from human embryonic stem cells.

Increased functionality of nanoscale morphology, coupled with the control of a biomaterial surface’s chemical and physical interactions, is improving biocompatibility, immune system stealth and drug release. In the future, the increased surface functionality could provide reporting on the disease state and functioning of the biomaterial construct.

Stem cell research is another key area. The influence of the mechanical properties of the biomaterial substrata on stem cell differentiation is increasingly understood, as are the possibilities of the induction of stem cell plasticity by the control of the culture environment’s acidity. We can guess that researchers will take the next step and examine the plasticity of stem cells as controlled by their physical and biochemical interaction with the biomaterial that houses them. Indeed, as the production of stem cells becomes easier, the production of personalised, bespoke biomaterials will be enabled by the coating or construction of implants with the patient’s own cells, thus avoiding immune response problems. 3D printing is now ubiquitous, and the field of biomaterials is no exception.

However, the technology is moving rapidly from the production of prototype medical implant structures to full-scale production. As in every field of engineering, it is intriguing to speculate how the improved availability of 3D printing will impact on biomaterials research, industry and application.

At Swansea University’s Centre for NanoHealth, we have recently established an electrospinning R&D resource that builds on our rheometry and microscopy characterisation capabilities within nanotechnology. We use a standard needle electrospinning system to create novel biomaterial scaffolds, such as wound dressings with nanoparticles of controlled morphology immobilised in nanofibres to fight bacterial infection, and nano fibres with a sheath and a core of different materials for drug delivery and tissue engineering. We are also exploiting bowl electrospinnning, which allows scaffold production on a much larger, commercial scale.   

A look at 2013’s most exciting innovations in biomaterials science:  

Biocompatibility and bioactivity: hydroxyapatite
Materials experts at Lucideon (formerly Ceram, UK) have been working to tailor hydroxyapatite’s charge potential, the key factor affecting biocompatibility and bioactivity, by introducing different elements into the calcium phosphate lattice. Elements currently in development include silicon, silver and copper.   

Bone regeneration: radiopaque dicalcium silicate cement
A trial conducted by students at Chung Shan Medical University, Taiwan, observed significantly more bone regeneration from radiopaque dicalcium silicate cement (RDSC) than white-coloured mineral trioxide aggregate (WMTA) at three and six months, concluding that RDSC had the potential to be an improved alternative to WMTA in dental surgery.   

Bacterial adhesion: yttria-stabilised tetragonal zirconia
Yttria-stabilised tetragonal zirconia and 3mol% yttriastabilised tetragonal zirconia implants fail to remain stable over time. Researchers based at the University of Freiberg, Germany, conducted an in vitro study on the impact of various surface characteristics on initial bacterial adhesion. The results recommend lower surface roughness values.   

Sterility signage: colourimetric inks and modified atmosphere packaging
Colourimetric inks and modified atmosphere packaging have been combined by the University of Huddersfield, UK, to show a warning on previously used syringes. The syringe label remains deactivated in a nitrogenfilled blister pack. Exposure to air activates the o-crestolphthalein coated label, which rapidly absorbs CO2, turning the label red.   

Dental hypersensitivity: mesoporous bioactive glass
The specific properties of mesoporous bioactive glass (MBG) for reduction in permeability make it a potential material for treating dentin hypersensitivity, an issue that up to 30% of adults suffer from. A study at Kaohsiung Medical University, Taiwan, recommended that 30% phosphate MBG be used for dentinal tubule occlusion   

Microneedle-based adhesive: polystyrene and polyacrylic acid
Doctors at Brigham and Women’s Hospital, Massachussetts, USA, have developed a microneedlebased adhesive using a dual-layer system with a polysterene (PS) inner core and block co-polymer outer layer, made from PS and polyacrylic acid (PAA). PS was chosen to ensure the two layers did not delaminate and PAA to ensure adhesion