Visual identification, analysis and modelling of sterilising grade filtration for liposome enveloped products

点击翻译按钮获取中文摘要

Bioprocess challenge the project seeks to address:Sterile filtration is essential to the manufacture and safety of biological medicines. The performance of these filtration systems is an industrially relevant challenge that continues to evolve along with next generation therapeutics including viral vectors and liposomes. These products can present difficulties during sterile filtration due to their relatively large size leading to retention within the filter structure. The increasing importance of liposomes has been highlighted by the success of Covid-19 mRNA vaccines which are enveloped and delivered in liposomes. In this project we will combine the high-resolution imaging techniques of confocal microscopy and x-ray computed tomography to measure the means of entrapment for biological components within the filter membrane. Understanding these mechanisms will enable a rational approach to determining operating conditions, membrane type and formulation conditions for sterile filtration of these products.Objectives:- Develop imaging approaches to visualise feed material retention for liposome products, formulations in a range of filter types whilst minimising sample interference- Identify different foulants in complex formulations as they pass or block the filter- Combine information with complementary techniques to determine where and why fouling is occurring to develop predictive models- Apply the knowledge gained to various Pall systems, for example pleated sheet cartridges and TFF systems to demonstrate robustness of the research projectProject Description:Deterioration of performance during sterile filtration of lipid enveloped products e.g. mRNA vaccines is a commonplace issue for industrial scale bioprocesses [1, 2]. At UCL and within the Pall-UCL Centre of Excellence various high-resolution imaging techniques have been successfully used to visualise separation media, including X-ray CT, confocal microscopy, electron microscopy and focused ion beam microscopy. The objective is to characterise the structural features of these materials that determine their bioprocess performance [3-5]. This EngD aims to apply these methods in order to understand Pall sterile filtration separation membrane systems.Each imaging technique has inherent advantages and limitations, we aim to complement relevant approaches to maximise information gathered. For example combining the capabilities of X-ray CT to measure the 3D structure of the membrane with confocal microscopy to identify fluorescently tagged biological components [5] enables the identification of the regions where those components are trapped within a membrane. These can then be correlated with structural features such as an internal pore size decrease or tortuosity increase. The research will combine the information from these various techniques in order to build towards a mechanistic model [6] to predict sterile filtration membrane performance for liposomes.Investigating and comparing multiple sterile grade membranes and liposome types during this project will be used to deepen this mechanistic understanding. We are able to make use of the latest microfluidic liposome synthesis technology (developed by Precision NanoSystems) within the project to further this objective.