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Global food production needs to increase in order to meet the demands of an ever growing global population. As resources are finite, the most feasible way to meet this demand is to minimize losses and improve efficiency. Regular monitoring of factors like animal health, soil and water quality for example, can ensure that the resources are being used to their maximum efficiency. Existing monitoring techniques however have limitations, such as portability, turnaround time and requirement for additional reagents. In this work, we explore the use of micro- and nano-scale electrode devices, for the development of an electrochemical sensing platform to digitalize a wide range of applications within the agri-food sector. With this platform, we demonstrate the direct electrochemical detection of pesticides, specifically clothianidin and imidacloprid, with detection limits of 0.22 ng/mL and 2.14 ng/mL respectively, and nitrates with a detection limit of 0.2 µM. In addition, interdigitated electrode structures also enable an in-situ pH control technique to mitigate pH as an interference and modify analyte response. This technique is applied to the analysis of monochloramine, a common water disinfectant. Concerning biosensing, the sensors are modified with bio-molecular probes for the detection of both bovine viral diarrhea virus species and antibodies, over a range of 1 ng/mL to 10 µg/mL. Finally, a portable analogue front end electronic reader is developed to allow portable sensing, with control and readout undertaken using a smart phone application. Finally, the sensor chip platform is integrated with these electronics to provide a fully functional end-to-end smart sensor system compatible with emerging Agri-Food digital decision support tools.

Bovine antibodies, such as immunoglobulin G (IgG), cannot pass the placental barrier and as such are not transferred from the mother to the foetus, in utero. Instead a calf must absorb antibodies following ingestion of colostrum postpartum. Failure of Passive Transfer (FPT) is a condition that predisposes calves to development of disease and increases the risk of mortality. Thus, continuous early monitoring of IgG absorption in a calf, within the first 24 hours of life, is imperative to allow faster treatment and prevent FPT. In this paper, we present the development of a label-free impedimetric immunosensor device for bovine IgG in serum and demonstrate its suitability to determine early FPT in new-born calves. The developed sensors were challenged to discriminate between new born calf sera, both pre- and post-colostrum feeding, and demonstrated efficent detection of IgG in under 15 minutes. Such a device could enable rapid determination of FPT, thereby improving calves’ vitality and survival rate

In veterinary medicine, diagnostic tools enabling early detection of infectious disease in cattle could play a pivotal role in the control and eradication of bovine viral diarrhoea (BVD). Early identification of cattle persistently infected with bovine viral diarrhoea virus (BVDV) is critical for early diagnosis and isolation of the animal from a susceptible herd. The immediate availability of electronic test results to a veterinarian on-farm, would eliminate the need to submit samples to a commercial laboratory thereby improving animal therapeutic outcomes considerably. An impedimetric silicon chip-based biosensor platform, containing six gold nanoband electrodes as six individual sensors, was developed in this study for detection of BVD disease target molecules. Gold nanoband electrodes were first coated with an electrodeposited polymer and then modified with either monoclonal antibodies or Erns protein, for the subsequent detection of BVD virus and antibodies in whole serum, respectively. We demonstrate that the nanoband sensors have sufficient sensitivity and specificity for serological detection of both targets, with a low time-to-result (20 minutes). All serological samples were benchmarked against, and in complete agreement with, gold standard commercial ELISA methods. These initial proof-of-concept findings are of particular significance for potential on-farm point of use applications, where rapid analysis times and specificity are required to permit early diagnostics by veterinarians.