The thickness of a single human hair, the ‘rockets’ are produced using a solution of dissolved silk mixed with an enzyme which is then printed using a 3D inkjet printer. Methanol is then printed on top, and the methanol molecules trigger a reaction with the enzyme propelling the rocket forward.
When drug molecules are then attached, the formulation becomes a safe drug delivery platform, explained Dr Xiubo Zhao from the Department of Chemical and Biological Engineering at University of Sheffield
“Many pharmaceutical ingredients - antibodies, DNAs/RNAs, proteins/peptides etc - could be incorporated into the silk micro rockets,” he told in-Pharmatechnologist.com.
“We can simply blend them into the silk ink before printing as long as these pharmaceutical ingredients do not significantly change the properties of the silk ink.”
He added: “The other way to attach the ingredients is to covalently react with printed rocket. This is particularly useful for antibodies [and] receptors which work at the surfaces. This can be done through reactive inkjet printing at the end of the fabrication process. And this is also one of the advantages of this fabrication technology.”
The team of engineers in Sheffield, UK believe the delivery system can offer pharma firms a safe and flexible platform for delivering drugs into patients due to the degradable nature of silk within biological systems.
“Our [rockets] are made of silk which is a protein from silk worm and can be degrade into amino acids,” said Zhao, who added it is a US FDA approved biomaterial widely used in many medical applications.
“Previous devices need metal evaporation of, for example, e.g. Platinum as a catalyst layer for generating the power. This step is more expensive and complex than printing. Platinum cannot be degraded and will cause biofouling due to the adsorption of proteins, hydrocarbons onto the surface.”
The research was funded through a grant from the UK’s Engineering and Physical Sciences Research Council (EPSRC).
“We have not tried to approach any Pharma in this research yet,” Zhao told us. “We would be happy if any Pharma company have interest to work with us to develop this into real world applications.”