Intertronics
Diagnostic glove
The Department of Automatic Control and Systems Engineering (ACSE) at The University of Sheffield is developing a diagnostic glove that includes several flexible bioelectronic sensors with the help of 3D printing.
This will improve the way recovery from injury and the progression of neurological/musculoskeletal conditions are monitored.
The sensors are formed from elastomers mixed with various conductive nano or micro particle compounds, like graphite, platinum and silver, which are 3D printed onto the glove’s material.
The compounds are required to be dispensed in tiny amounts, to achieve this the ACSE team uses an extrusion-based 3D printer. However, at the beginning, particle aggregates were forming during the dispensing and particle distribution was being altered.
The ACSE team got in touch with Intertronics, who recommended Preci-Tip Precision Dispensing Tips. The design of which features a streamlined conical fluid path, which helps to deliver smoother, higher fluid flow rates and lower dispense back pressure compared with most standard dispensing tips, resulting in improved accuracy and much reduced clogging.
Paul Whitehead, Strategic Accounts Manager at Intertronics, said: “The results were better definition and a more reliable system, without blockages during the 3D printing process. However, further discussion revealed that they had challenges with the mixing of the filled polydimethylsiloxane (PDMS) mixtures.”
Intertronics
THINKY mixer
The process involved mixing nanoparticles into the very viscous PDMS to produce a graphite composite. The ACSE team added an organic solvent to reduce the viscosity of the mixture. The solvent had to be removed post printing, and this required testing to confirm there was no remaining contaminating solvent, which meant there were health and safety considerations for the team in using this approach.
To address this issue, Intertronics suggested the team consider trialling a THINKY Mixer to achieve better mixing success. The industrial non-contact planetary centrifugal mixing machines use both rotation and revolution of material in a container under an acceleration of 400 G to achieve consistent mixing results.
Tom Paterson, Postdoctoral Research Associate at The University of Sheffield, said: “We’ve removed the need for solvents, which removes a step from the process, improves health and safety, and removes the regulatory requirement to prove this compound has been removed.”
