Skip to main content

Engineering selective elements for disposable point of test sensor chips

Final Activity Report Summary - NANODAT (Engineering selective elements for disposable point of test sensor chips)

Globally, there is a growing problem of drug driving. It is believed that drugs of abuse contribute to up to 25% of fatal road accidents. Governments worldwide are introducing legislation for road side testing. As yet no suitable instrument is available on the market. The routine test for the detection of drugs measures the level of metabolite in urine, which is not practicable for road side testing nor indicates drugs taken in the last few hours. Detecting drug traces directly in oral fluid has been identified as the best roadside method of detection. There are significant challenges as the sample is small and detection levels are ppb. A global need exists for cheap drugs of abuse test (DAT) using saliva for roadside use by people who are not medically trained.

NANODAT addresses these issues by introducing a technology, based on molecular imprinted polymers (MIPs), to a DAT sensor platform. MIPs can replace costly and less stable antibodies leading to mass-producible and cost-effective systems for DAT applications. The shelf life of the systems will be improved by a factor of at least ten. The basic concepts and knowledge to be developed and transferred have widespread applicability in fields outside of DAT such as clinical and environmental process control. The main scientific and technological objective of NANODAT is the design of a miniaturised sensor technology as a platform for detection of relevant drug analytes and their metabolites. The nanostructured biomimetic materials will overcome both the stability and short shelf life problems inherent to antibody based systems. Microfluidic devices will also be developed that need minimal sample volumes. There were a total of 6 technical deliverables and milestones were associated to be achieved. These were as follows:

M1. Recruitment for NF 1-3 has been finalised.
D1.1 Protocols for controlled deposition of MIPs on metal and glass surfaces and membranes.
D1.2 Several hybrid polymeric structures with optimised recognition and signalling functionalities.
D2.1 Protocols for synthesis and characterisation of MIP nanoparticles.
D2.2 Protocols for synthesis of MIP nanoparticles with fluorescent and catalytic properties.
D2.3 Samples of MIP-hybrid nanoparticles for testing in sensors/assays.
M2. Protocols for synthesis of new materials with required selectivity and affinity are available.

Deliverable D1.1 was completed on schedule, with clear demonstration of controllable layer thicknesses for optical and amperometric applications. A number of methods for grafting MIP layers with using seed nanoparticles with optimised recognition and signalling functionalities were established, thus closing out deliverable D1.2. Protocols for the synthesis and characterisation of MIP nanoparticles, which were subsequently tested for affinity for both cocaine and THC, were established in year 2 in fulfilment of deliverables 2.1 and 2.3 respectively. The successful synthesis and characterisation of this variety of grafted MIP layers and nanoparticles resulted in milestone M2 being passed according to the project schedule.

At the start of the third second year of the project, five of the six technical deliverables and milestones for work packages 1 and 2 had been completed. The remaining deliverable was D2.2 "Protocols for synthesis of MIP nanoparticles with fluorescent and catalytic properties". During the third year of the project, significant progress was made towards proof-of-principle of operation of an electrochemical sensor for drugs of abuse detection, in partial completion of deliverable D2.2. Using the grafting methods developed and previously reported in the NANODAT project, hybrid MIP polymer bearing integrated catalytic centres were successfully grown onto a gold electrode and used to electrochemical detection of the model compounds catechol and dopamine. In addition, no response was obtained in the presence of interfering reagents such as phenol or resorcinol. This represents a significant step towards the demonstration of a hybrid MIP electrochemical sensor for drugs testing.