Affordable Low-volume Printed High-throughput Assays (Project ALPHA)

There are major global health challenges where we need to discover new drugs urgently, such as when tackling antimicrobial resistance (AMR) or when driving new approaches to cancer treatment. Our ability to identify the right treatments is directly linked to how many potential drugs can be tested against the ever growing range of targets. National investments in responding to these challenges has been significant with large, centralised investments in facilities that can use high-throughput screening techniques to test large numbers of potential drugs. Through this project we want to now scale-out the testing capability to reach unprecedented numbers of researchers, giving as many labs as possible the research tools to test ideas rapidly by dramatically decreasing expensive reagent use and the size of equipment footprint, dropping the currently prohibitive costs for most labs.

These tests are carried out in assays so miniaturising the required sample or reagent volumes is critical to maximising the number of possible tests. Miniaturisation has been a focus since the 1990s, enabling more parallel analyses. While rare in an academic environment, there are 3456 reaction zones, or wells, on the most advanced industrial plates, each carrying out one assay, testing a drug with a target. This proposal is pushing to drive a dramatic shift to over 17 million tests in the same plate size, with each well providing a 3D, biologically relevant, micro-environment for cell-drug interactions, mimicking their natural environment.

The unique core printed technology is developed in Department of Engineering, working with Department of Chemical Engineering and Biotechnology and Cancer Research UK (Cambridge Centre) for this proof-of-concept. The cutting edge discovery by the PI and co-I Researcher is that inkjet printed drops can be captured at fluid surfaces, with each trapped as a microscale well. The PI has previously reported controlling and capturing similar arrays of liquid droplets. 50,000 times less material is needed per well and the surprising ease of liquid handling requires relatively simple robotics. There is digital control over the creation of the 'plate' for every array of assays, turning each to a user-defined size. This minimises waste dramatically while also ensuring the lowest possible environmental impact through minimal reagent and plastics material usage. The team aims to ensure affordability and rapid research uptake by coupling reagent minimisation with simple off-the-shelf automation.

The overarching hypothesis is that we can firstly use an all-fluid printing technique to create an ultrahigh-throughput screening technology, with over 17 million tests in the same plate size, with each well providing a 3D, biologically relevant, micro-environment for cell-drug interactions. Secondly we will integrate this into a low-cost automated process.

In the proposed project, a curable fluid surface is printed, defining the plate area. To create the assays, printed drops hit the fluid surface, sink to a position where a small proportion of each drop protrudes slightly above the interface, where if subsequent drops hit then they will coalesce and mix with the first drop. A bio-ink (containing target cells for example) will be in the first drop, creating a micro-well trapped within a fluid matrix. Subsequent printed drops with test drugs, or simply to modify concentration, can be delivered and the micro-well expands, remaining separate and stable from the other wells. The wells containing reagents can be trapped in a solidified matrix by curing.

The 12 month programme brings together experts in inkjet printing, array fabrication, biological assay development and assay analyses.

- WP1 focuses on developing and assessing the core technology. This will tackle the 'plate' material printing and curing, the printed reagent formulations and printability assessment, examining the time-linked kinetics of stability, and the assessment of three model assays.

- WP2 examines the range of advanced metrology approaches. Here comparative analyses will determine feasibility of low cost routes (i) for characterisation and (ii) for Big Data management.

- WP3 integrates the two experimental research stages, ready to test roll-out in the Dept. of Chemical Engineering and Biotechnology, and in CRUK Cambridge. Demonstrators have been defined as key outputs to these work packages and will be guided by consulting the full team and an external expert.

This project will have specific impact at (at least) four levels.

1. Drug Discovery Impact
This impact stream is focused on ensuring that the developed tool has a route to SMEs, spin-outs and academic labs. The goal is a dramatically increased testing schedule while minimising cost, waste and research time. This impact stream has a series of activities, such as:
(a) extending an existing group website to include a forum for interaction and feedback with target researchers,
(b) hosting two discussion groups (academic and industry focused) at the Institute for Manufacturing (IfM) to focus on drug testing infra-technology needs. Local hosting is chosen to ensure no on-cost at this stage,
(c) translating research findings to standard operating procedures and 2 roll-outs of the system (Dept. of Chemical Engineering & Biotechnology and CRUK Cambridge Institute),
(d) engaging with large firms invested in high density array technologies to understand barriers to validation.

2. Digital Manufacturing Impact
There is a concurrent development in inkjet capabilities across medical device and pharmaceutical industries. It is expected that the roll-out of inkjet-tested assays here will increase the publication of bio-inks and compatibility with printheads. This is expected to provide helpful guidance for low-cost sensor printing, personalised drug delivery printing, biocompatible printhead design, etc. There are milestones planned, including reaching out through a hosted website, Cambridge Network (network of >1500 companies) events and an in-house workshop, to engage firms who will ultimately provide components for future tools.

3. Public/Societal Impact
(a) We will engage with the general public to clearly communicate that the reduction in cost and material wastage is in addition to the potential to dramatically increase the number of tests that can be carried out when researching new treatments, rather than purely as a cost-cutting exercise.
(b) Outreach to the general public will be through 2 main outlets. Firstly, the PI runs a large printing and microscope workshop at the Cambridge Science Festival at the end of March, with over 1,200 people visiting. This will be coupled with an interactive Virtual Reality demonstration.
(c) Targeted communications will be written for publication in Research Horizons (University of Cambridge), The Manufacturer and the IfM Review.
(d) The PI and Co-Is are all engaged closely with the EPSRC Centre for Doctoral Training in Sensor Technologies as well as delivering Bioengineering, Biotechnology and Manufacturing teaching at University of Cambridge. This project will lead to supported short research projects for students as part of their course.
(e) The ultimate societal goal of this work is to help researchers by providing access to previsouly prohibitively expensive tests to identify new molecules or treatments in their area of study, from cancer research to the next generation of antibiotics.

4. Academic Impact
Impact will be achieved by bringing together lab-based researchers, SMEs, spin-outs and equipment solution providers to discuss ultra low-volume and low-cost systems for researchers. This work is anticipated to enhance academic-industry collaboration and enable continution of the research far beyond the lifetime of this initial project throughpublic and direct industry funding. We expect at least 2 publications in top journals. We also expect to deliver 2 invited plenary talks at international conferences on printed sensors (SPIE), inkjet of pharmaceuticals (The IJC).