Sensing bone regeneration with conductive inks
What is the aim of your research on new biocompatible conductive inks for sensing bone regeneration?
Ana Maria Escobar: Monitoring of bone regeneration after a fracture is the first objective of our research, because up to 60 % of open tibial fractures fail to unite, and this leads to delayed union and even non-union. This issue has a huge impact on the patient’s quality of life and on national health-care systems by increasing the volume of repeat operations. Temperature, pH and pressure sensors, and antennas are being manufactured for wireless monitoring of bone healing.
Consequently, biocompatible, conductive and low-cost nano-inks are also being developed. Our research forms part of the Smart Bone Regeneration (SBR) project and is related to the work programme topic ‘Regenerative medicine: from new insights to new applications’ as part of the EU’s Societal Challenge 1 ‘Better health and care, economic growth and sustainable health systems’.
How do the inks work?
Ana Maria Escobar: Our novel conductive inks are based on metallic nanoparticles that are printed, dried, and sintered onto biocompatible flexible substrates, such as cellulose. Sintered metallic inks based on Ag or Pt nanoparticles are very electrically conductive.
However, they are usually based on dangerous (i.e. flammable) and toxic solvents, such as methyl ethyl ketone and aromatic solvents. In our research, all dangerous and toxic solvents contained in ink formulations have been replaced by water-borne solutions. Furthermore, the antennas and sensors are manufactured by additive printing techniques, which are considered to be cost effective and environmentally friendly methods, compared with conventional ones. Indeed, the inks we have developed are capable of curing at low temperatures, and so have very low energy consumption.
What is the status quo of your project?
Ana Maria Escobar: A biocompatible, water-borne, platinum 3D dispenser ink has recently been developed in the project by Leitat. 3D dispenser has been selected as the most suitable printing technology due to its flexibility and potential adaptability to print highly conductive inks for new sensor designs, which can be easily integrated into the implant body.
Promising results regarding the electrical conductivity of 3D dispenser printed inks have been obtained. Some of the additional ink requirements are processability at low temperature and compatibility with polymeric substrates. All the unique characteristics provided by our novel green electronic inks will accelerate the time-to-market by ink formulators, such as one of our partners: Genes.
In general, how can printing inks improve applications in the medical sector?
Ana Maria Escobar: Smart (bio)sensors with wireless connectivity are gaining more and more attention for use in health screening, monitoring, diagnosis and treatment purposes, because they are non-invasive, easy to use, and offer real-time monitoring.
In addition, all collected data can be analysed by artificial intelligence with a view to predicting, for example, implant acceptance and bone healing. The latest work on the development of new printing inks is focused on avoiding toxic compounds and lowering the curing temperature, and so extending their use on potential biocompatible thermolabile natural and/or polymeric substrates.