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Title: Inkjet printing of biological macromolecules for use in biology and medicine
Author: Cook, Christopher Charles
ISNI:       0000 0004 2708 2691
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2011
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This thesis presents an investigation into the viability of utilising piezoelectric drop on demand printing as a tool for the deposition of proteins for the rapid prototyping of biological sensors. The work has focussed on several main aspects; the effect of printing parameters on drop characteristics, the effect of printing parameters on protein survivability, the influence of surface characteristics on the drop formation at the surface of the sensor, and the electrochemical properties of the sensors after printing. The main objective of this study was to derive a method for the rapid prototyping of sensors using the piezoelectric drop on demand printer. The first section details the influence of waveform amplitude on the characteristics of the printed drop including droplet weight and volume. It was established that proteins were suitable for printing in both a Phosphate buffered saline solution and a sugar based carrier solution as supplied by AET. Protein survivability experiments suggested that there was some loss of activity during the printing process which required further investigation. Research into the effect of printing parameters on the viability of proteins, specifically Glucose Oxidase (GOX) has been categorised according to protein structure and protein conformation. No damage was found to occur to either protein conformation or structure after analysis of the samples using light scattering, analytical centrifugation and circular dichroism after printing at 40, 60 and 80V. Further analysis revealed that there was a loss of mass of protein after the printing process compared to a non printed sample. Surface analysis was employed to quantify the effect of the surface of the electrodes on the drop behaviour after printing through a piezoelectric drop on demand printhead. Proteins were printed onto different carbon surfaces for comparison in different holding solutions and the surfaces analysed for both the drop behaviour when wet and the form and size of the dried enzyme on the carbon surface. Printed samples were observed to spread best with surfactant present in the solution and some evidence of a 'coffee staining effect' was encountered. Further optimisation of the surfactant percentage and the drying conditions ameliorated these effects to produce optimal drying of the solution both on the surface and after drying. An electrochemical technique was also employed to optimise the number of units of enzyme deposited using the printing technique and to ensure that the current response required was achievable and repeatable. After optimisation, it was possible to demonstrate that the 3 unit sample provided a current response with an R2 value greater than 0.99, therefore demonstrating reproducible linearity in the current response. This therefore demonstrated that piezoelectric drop on demand printing techniques could be used for the rapid prototyping of biosensors, especially for use in the glucose sensing market.
Supervisor: Derby, Brian Sponsor: Xaar Plc ; Applied Enzyme Technologies Ltd
Qualification Name: Thesis (Eng.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: Printing ; Proteins