Understanding the impact of the engineering environment on transient transfection and process scale-up

Transient gene expression (TGE) is traditionally used for rapid production of recombinant proteins to support preclinical studies during drug development. This technology involves introducing plasmid DNA into mammalian cells which then express the protein of interest over a limited period of time, typically two weeks. In recent years, there have been some advances in this technology which have led to an increase in titres from mg/L to g/L. These advances, combined with a robust, scalable and well defined process, provide an opportunity to explore TGE as an alternative tool for rapid production of clinical material (e.g. in a pandemic situation or in the context of personalised medicines). The purpose of this research is to elucidate the effect of transfection agent addition (volume, concentration etc), agitation mode, bioreactor geometry and operating conditions on cell growth, DNA uptake, and productivity in a transient transfection process and apply the findings to define an optimal scaling methodology valid up to 200L scale. The proposal is to study the process using scale-down bioreactor systems that most accurately reflect the geometry and flow conditions This builds upon scale-down models and fluid dynamics characterisation methods already available at UCL (see below) to enable rapid progress and generation of results. The doctoral candidate will contribute to the project and will focus on the following objectives:

Improve process understanding through advanced engineering characterization in customised systems. Mixing kinetics will be evaluated for different operating conditions using a model system based on current processes, in both rocked and stirred bioreactor configurations, and the impact of fluid rheology and feed location will be evaluated using scale-down mimics of the industrial systems.
Establish optimum transfection conditions in specified bioreactor geometries. This will also enable reliable scale translation of transfection conditions between different bioreactor geometries i.e. wave to stirred configurations.
Conduct biological verification experiments at scale. A transient transfection process model will be established with associated analytics and experiments will be run using agitation strategy, aeration and feed location as informed by the characterization studies.

This project will be part of the UCL-AstraZeneca Centre of Excellence (CoE) that is a joint collaboration between University College London (UCL) and AstraZeneca. The centre's aim is to generate a set of predictive decisional tools for both upstream and downstream biopharmaceutical processing activities. This involves the application of micro-scale and high-throughput studies involving correlation development, multivariate data analysis (MVDA), process economics and discrete-event optimisation. The candidate will join a team of PhD and postdoctoral researchers working in the CoE across upstream and downstream processing as well as modelling tools. The project will be hosted by the department of Biochemical Engineering at University College London in collaboration with AstraZeneca sites across Cambridge (UK) and Gaithersburg (US).

The CDT has a proven track record of delivering impact from its research and training activities and this will continue in the new Centre. The main types of impact relate to: (i) provision of highly skilled EngD and sPhD graduates; (ii) generation of intellectual property (IP) in support of collaborating companies or for spin-out company creation; (iii) knowledge exchange to the wider bioprocess-using industries; (iv) benefits to patients in terms of new and more cost effective medicines, and (v) benefits to the wider society via involvement in public engagement activities and impacts on policy.

With regard to training, provision of future bioindustry leaders is the primary output of the CDT and some 96% of previous EngD graduates have progressed to relevant bioindustry careers. These highly skilled individuals help catalyse private sector innovation and biomanufacturing activity. This is of enormous importance to capitalise on emerging markets, such as Advanced Therapy Medicinal Products (ATMPs), and to create new jobs and a skilled labour force to underpin economic growth. The CDT will deliver new, flexible on-line training modules on complex biological products manufacture that will be made available to the wider bioprocessing community. It will also provide researchers with opportunities for international company placements and cross-cohort training between UCL and SSPC via a new annual Summer School and Conference.

In terms of IP generation, each industry-collaborative EngD project will have direct impact on the industry sponsor in terms of new technology generation and improvements to existing processes or procedures. Where substantial IP is generated in EngD or sPhD programmes, this has the potential to lead to spin-out company creation and job creation with wider economic benefit. CDT research has already led to creation of a number of successful spin-out companies and licensing agreements. Once arising IP is protected the existing UCL and NIBRT post-experience training programmes provide opportunities for wider industrial dissemination and impact of CDT research and training materials.

CDT projects will address production of new ATMPs or improvements to the manufacture of the next generation of complex biological products that will directly benefit healthcare providers and patients. Examples arising from previous EngD projects have included engineered enzymes for greener pharmaceutical synthesis, novel bioprocess operations to reduce biopharmaceutical manufacturing costs and the translation of early stem cell therapies into clinical trials. In each case the individual researchers have been important champions of knowledge exchange to their collaborating companies.

Finally, in terms of wider public engagement and society, the CDT has achieved substantial impact via involvement of staff and researchers in activities with schools (e.g. STEMnet), presentations at science fairs (Big Bang, Cheltenham), delivery of high profile public lectures (Wellcome Trust, Royal Institution) as well as TV and radio presentations. The next generation of CDT researchers will receive new training on the principles of Responsible Innovation (RI) that will be embedded in their research and help inform their public engagement activities and impact on policy.