CASE STUDIES

Assay kits for transplant organ viability6th Nov 2013

B.M. Thomson, M.F. Smith, C. Tuinea-Bobe and B.R. Whiteside

Assay kits for transplant organ viability
The problem

The demand for donated organs greatly exceeds supply (1 donated liver per 3 people on waiting list in USA). A partial solution would be to improve the use of organs harvested from ‘marginal’ quality donors (e.g. controlled non-heart beating donors), since many of these ‘marginal’ organs are currently discarded.
 

Project aims

We are developing rapid, ‘point-of-use’ assays to help clinicians decide if the functional viability of a donated organ (e.g. a liver, kidney, heart or suspension of pancreatic islets) is sufficient for its use as a transplant.

We aim to: (i) increase organ availability by identifying acceptable quality organs from marginal quality donors; (ii) enable technical staff to avoid wasting resources on non-viable organs; (iii) allow newer transplant procedures (e.g. pancreatic islet transplantation) to be optimized through improved in-process monitoring; and (iv) enable regulatory compliance by demonstrating the identity, safety and efficacy of donated materials before they transplanted.

Our assays are designed to facilitate clinical decision-making within the timescales and practical constraints of an operating theatre/ clean room rather than for use in scientific research laboratories (i.e. rapid, intuitive and error-free use by available staff; minimal additional costs; 4 degrees C storage; disposable components; self-evident relationship between assay biochemistry and sample viability).

The technology

To use the assay kits, tissue samples are placed into the chambers of an assay cassette. The lid is peeled off the reagent tray, and the assay cassette inserted into chemicals contained within the wells of the reagent tray. Biochemical reactions produce colour changes proportional to the samples’ functional viability.

The colour change may be recognised ‘by eye’ or quantified using image analysis software running on a laptop computer. Results are standardised by comparison with a ‘calibration sticker’ affixed to the assay cassette and are compared automatically with stored historical data. The assay cassette is the same size as a microscope slide and may be retained for more detailed examination.

Picture shows an assay cassette on the reagent tray.

The assay hardware was developed using CAD (Hexagon II and Solidworks); 3D printing (selective laser sintering; Keyworth Engineering Ltd); rapid prototype injection moulding (Protomold Ltd); ultrasonic welding and computer-controlled laser cutting (Bradford University Nanofactory); and specialist printing (Mercian Labels Ltd). Designs, specifications and results are documented to ISO13485 in preparation for CE marking.

The team

The work has been performed by AedStem Ltd in collaboration with Leeds, Bradford and Newcastle Universities. Clinical direction has been given by Prof J. Shaw (Newcastle). The project was begun with Regener8 funding and has been supported, in part, by IKC and TSB.
 

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