Sculpting Dynamic Amphiphilic Structures

Biomembranes lie at the heart of most biological function, and lipid membranes are increasingly finding a wide range of novel applications in biotechnology and nanomedicine. Such self-assembled amphiphilic interfaces can adopt an astonishing range of complex shapes and liquid-crystalline structures ordered in 1, 2 or 3 dimensions, over length scales stretching from 2 - 3 nanometres, to microns. Gaining an understanding at a molecular level of how interface structure, ordering, dynamics and micromechanics depend upon chemical structure and composition, and thermodynamic variables such as temperature, hydration, and pressure, is the key to learning how we can manipulate such self-assembled soft interfaces to create novel and useful structures and new technologies, and this is the main aim of this Programme.

We have identified three key underpinning basic science challenges: 1) asymmetry; 2) patterning; 3) curvature, long-range organisation and symmetry. There are four main aspects underlying these challenges which we consider are of crucial importance: i) compositional asymmetry and dynamics of amphiphile flip-flop across bilayers; ii) lateral segregation, line tension and microdomain formation; iii) membrane curvature and curvature elasticity; iv) charge and dipolar interactions between lipid headgroups. Furthermore, there is a complicated coupling between all of these four aspects, and this is where we will focus much of our attention.

We have assembled a team of five leading UK University research groups, spanning Chemistry, Physics and Biophysics. The groups have complementary expertise covering laboratory-based and synchrotron time-resolved X-ray diffraction, neutron scattering, solid-state nuclear magnetic resonance, calorimetry, biomolecular force microscopy, Langmuir trough and microfluidics technologies, linear and non-linear spectroscopies, atomic force microscopy, spectroscopic and optical imaging, optical tweezers, microrheology, and theory. These approaches will be used to attack different inter-related aspects of the three key basic science challenges. We will ensure an efficient translation and synthesis of all of the findings, by a tightly- regulated management structure, and by regular meetings and staff exchanges between the five research groups.

Building on the engineering rules and technologies developed previously in the programme, we will integrate the earlier work to develop lipid structures into active lipid systems such as: self-encapsulated droplet interface bilayer networks in water; patterned asymmetric vesicles of defined size: coupling microfluidics with smart droplet microtools; phospholipid phases and vesicles in thermal gradients.

We will then use this knowledge to develop three demonstration systems:

i) Artificial Organelles. The development of artificial organelle machines which mimic some of the remarkable functions and properties of biology will lead to new approaches for personalized healthcare.

ii) Rapid drug-membrane binding screen. A compartmentalised, rapid drug screening device will allow parallel measurements of drug interactions with a number of artificial plasma membrane mimics (PMMs) formed by an array of parallel droplet interface bilayer or vesicle networks.

iii) In-Cubo Crystallization of Large Membrane Proteins. Learning how to swell lipid cubic phases will unlock our ability to construct cubic scaffolds with unit cell dimensions of the order of tens or hundreds of nanometres, allowing incorporation of large membrane proteins (>50kD), which are major drug targets for the pharmaceutical industry.

Further biological and biotechnological applications will be developed during the course of the Programme by the current Investigators and a wider group of industrial and academic collaborators, who will be brought into the Programme as appropriate.

Our ambition within this Programme grant is to exploit the emerging field of molecular membrane engineering, by designing and constructing new biologically-inspired parts, devices and systems with user-defined levels of asymmetry, patterning and curvature. This will revolutionise the design and fabrication of smart, soft materials based on the lipid bilayer as the basic structural motif, with morphologies spanning the nano to micron lengthscale, and dynamics controlled over a wide range of timescales. In the longer term this will lead to a paradigm shift in areas such as nanomedicine, bioelectronics, biological computing devices and synthetic cells.

To achieve this we will bring together five leading UK research groups to investigate experimentally and theoretically the rules underpinning the self-assembly, ordering and dynamics of amphiphilic systems.

This knowledge will then be exploited:
i) to develop quantitative engineering rules for construction of 2-D and 3-D membrane-based structures with targeted asymmetry, patterning and curvature, focussing initially on purely lipid-based systems;

ii) to design self-assembled, fluid, amphiphilic systems with useful functional properties;

iii) to develop demonstrate applications, such as artificial organelles, high-throughput screens for drug discovery, and swollen cubic phases for membrane protein crystallisation.

We plan to invite companies with interests in these areas to participate by funding Industrial PhD Students from year 3 onwards to develop the applications, and to help embed the knowledge gained within an industrial context. We will spend £10k from our own resources on direct commercialisation activities, led by the ICB and the PM. They, together with the consortium, will:

a) network with relevant TSB Knowledge Transfer Networks and other industrial networks that may have an interest in these technologies;

b) develop Outline Concept Specifications documents as a starting point for discussions with potential users and developers of the technologies;

c) form an Industry Consortium. In the final year of the project, an Industrial Showcase event will be held at Durham.

As this project extends the current state-of-the art we expect to generate intellectual property with significant commercial value, and will protect it via established technology transfer organisations who will cover the patenting costs. A consortium agreement will govern the IP generated, and the Advisory Board will be bound by a confidentiality agreement.

We will organise a Workshop in year 3, with invitees from both academia and industry, and an International Meeting in year 5. We will embed public engagement activities within the Programme, such as the Royal Society's Summer Science Exhibition. We will highlight the field of self-assembled complex soft materials by making conference lectures freely available on iTunesU /YouTube and by a radio broadcast produced as part of the Imperial College Institute of Chemical Biology DTC Science Communication course. This will complement dissemination via websites, meetings, conferences and journal publications.

We expect the more junior Investigators and some of the post-doctoral researchers to become research leaders, either in industry or academia, within 5-10 years.