Design and characterisation of a scale-down perfusion platform for mammalian cell process development

This project seeks to optimise perfusion processes via addressing two related challenges, namely:
- Scale-down and process verification of novel cell retention methodologies (AWS)
- Understanding steady state and maximise process performance and productivity

Objectives
- Design and build a small scale version of the AWS system, able to work with and fully connected to a 250mL perfusion bioreactor.
- Understand the limits of and characterize the "operating window" for AWS perfusion processes. Benchmark against other cell retention technologies.
- Understand steady state with respect to: cell size distribution, cell cycle distribution, primary metabolism, specific productivity. Model based process optimisation (perfused media, perfusion rate, target VCD at steady state).

Project Description
The Acoustic Wave Separator (AWS) technology developed by Pall offers a number of promising benefits such as: (a) not being susceptible to fouling, (b) being tuneable to allow for cell fractionation and conditional bleeding and (c) causing less stress to the cells. However, a scale down version amenable to high-throughput process development in small volume automated bioreactors does not exist. The aim is to develop, in collaboration with Pall, a scale down version of the AWS as a cell retention device in small volume bioreactors and to understand the limits of and characterize the "operating window" for continuous processes using the AWS technology.
Experimental investigations will be based on a fully controlled scale-down perfusion bioreactor recently developed at UCL. This novel 250ml bioreactor, specifically designed for mammalian cell cultivation under perfusion mode, is equipped with a Levitronix pump and TFF filter, used for cell retention. Perfusion runs at 1VVD have been successfully run and showed good reproducibility over 10 days. Expertise from Pall on the AWS and its operation will be key to select suitable scaling criteria.
Mathematical analysis and characterisation of the steady state will be based on a series of metabolic modelling and Systems Biology techniques recently developed at UCL. Process variables that will be studied both mathematically and experimentally at steady state include: cell size distribution, cell cycle analysis, primary metabolic uptake & secretion rates, amino acid uptake & secretion rates, cell viability and viable cell density.

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.