Recent advances in biomedical, biosensor and clinical measurement devices for use in humans and the potential application of these technologies for the study of physiology and disease in wild animals

Abstract

The goal of achieving enhanced diagnosis and continuous monitoring of human health has led to a vibrant, dynamic and well-funded field of research in medical sensing and biosensor technologies. The field has many sub-disciplines which focus on different aspects of sensor science; engaging engineers, chemists, biochemists and clinicians, often in interdisciplinary teams. The trends which dominate include the efforts to develop effective point of care tests and implantable/wearable technologies for early diagnosis and continuous monitoring. This review will outline the current state of the art in a number of relevant fields, including device engineering, chemistry, nanoscience and biomolecular detection, and suggest how these advances might be employed to develop effective systems for measuring physiology, detecting infection and monitoring biomarker status in wild animals. Special consideration is also given to the emerging threat of antimicrobial resistance and in the light of the current SARS-CoV-2 outbreak, zoonotic infections. Both of these areas involve significant crossover between animal and human health and are therefore well placed to seed technological developments with applicability to both human and animal health and, more generally, the reviewed technologies have significant potential to find use in the measurement of physiology in wild animals. This article is part of the theme issue 'Measuring physiology in free-living animals (Part II)'.

Keywords: MEMs; antimicrobial resistance; biosensors; neuroprosthetic devices; zoonoses.

Figure 1.

Conceptual scheme for a generic biosensor. The receptor layer can use many biological receptors (enzymes, antibodies, oligonucleotide sequences, aptamers, etc.) or non-biological entities such as molecularly imprinted polymers (MIPs) or various chemical functionalities to increase selectivity. Detectable analytes include: chemical species, nucleic acid sequences and proteins. The transducer element refers to the underlying sensor principle, of which there are many, including: optical, electrochemical, piezoelectric, thermal and electrical sensors. (Online version in colour.)

Figure 2.

Architecture of the SiNAPS probe and of the recording system. (a) Implantable CMOS (complementary metal-oxide semiconductor) probes with dense electrode arrays can record broad-band bioelectrical signals across brain circuits with sub-millisecond and single-neuron resolutions. (b) Comparison of the integration potential of simultaneously recording electrodes (i.e. channels) per total silicon area (i.e. shaft and base of the probe) for different architectures proposed in the literature. SiNAPS probes achieve a number of effectively recording channels per unit of silicon area that is one order of magnitude larger than other presently available CMOS architectures and the NeuroPixels. (c,d) Schematics of the circuit architecture for the SiNAPS probe (c) and its acquisition system providing simultaneous neural recordings from the entire electrode array (d). Each electrode-pixel features an electrode and a small area DC-coupled in-pixel circuit for local amplification and low-pass filtering. A probe integrates multiple instances of the same low-area and low-power analogue front-end module of 32 electrode-pixels that are read out in a time-division multiplexed fashion. The on-probe digital control unit (DCU) provides the timing signals required for correct circuit operation and implements a bidirectional serial peripheral interface (SPI) for device configuration. A field-programmable gate array (FPGA)-based acquisition unit generates timing signals for the analog to digital converters (ADCs) and provides a camera link standard connection with a PC for data storage and online visualization [38]. TDM, time division multiplexing; VGA, video graphics array. (Online version in colour.)

Figure 3.

Overview of a dermal tattoo sensor produced using colorimetric inks for measurement of pH, glucose and albumin in interstitial fluid [64]. (Online version in colour.)