Biomimetic sensors are sensors inspired by biology, which aim to replicate natural methods, mechanisms, and processes.
Sensors are an integral part of many engineered products, systems, and manufacturing processes as they provide feedback, monitoring, safety, and a number of other benefits. Development of sensor technology risks stagnation when the current options for improvement or innovation are no longer competitive, but utilization of non-engineering concepts, such as biology, have introduced inspiration innovation for a variety of future technologies.
In particular, biomimetic sensor technology is an emerging branch of sensor research, which offers several advantages over traditional sensor technology. Nature has inspired a wide variety of sensors for navigation, spatial orientation, and prey and object detection, which provide engineers with new ideas for improvements to current technology, new sensor technology, and potential sensor miniaturization. Due to the requirement for sensors to sense unusual parameters, out-of-the-box thinking and borrowing ideas from naturally-chaotic biological processes can help circumvent problems with traditional sensors.
The majority of biomimetic sensors consists of potentiometric, voltammetric, and impedance spectrum sensors, modified with specific and designated biomimetic materials.These inputs allow a wide range of biologically-inspired stimuli and enable biology and engineering to solve a wide range of problems with traditional sensors.
Chemical type sensors identify and quantify specific substances or chemical reactions in a medium such as gas, liquid, or a mixture and selectively exhibit behavior based on desired target substances, with little or no interference from surrounding substances. Sensitivity, or the minimal concentration or change needed for successful sensing, is synonymous with resolution for chemical sensors.
Another researched application for biomimetic sensors is taste sensing, which aims to replace human taste and smell testers. The majority of these sensors fall within the chemoreceptor type. Biomimetic and biometic sensors based on taste cells, tissues, nerves, and enzymes as the sensing elements have been developed, with nanotechnology and microfluidic chips being utilized for the fabrication of the sensors.
Microchips with electrode recognition sites have been developed to measure taste and map the selected compound to the five primary tastes (salty, sweet, sour, bitter, and umami), which directly mimic the functionality of the human tongue. Piezoelectric quartz crystal mimics the human taste bud with molecularly imprinted polymer coating that is long lasting, has an enhanced memory effect, can be washed, and has high reproducibility. The bulk acoustic wave sensor demonstrates a shift in the frequency response, thus indicating the sensed analyte molecules.
Radiation type sensors are excited by the emission of charged (α and β particles and protons) or uncharged (neutrons) particles from atomic nuclei, or nuclear electromagnetic γ and x rays. These types of sensors either detect the presence of radioactivity or measure the radiative energy. Of the published biomimetic sensor research, none fits into this classification.
The strong affinity of biological receptors for their targets has been studied for many years and is beginning to be researched in connection to biomimetic sensors that are capable of detecting and reacting to specified biological and chemical compounds.
Non-covalent interactions between natural recognition elements and their ligands (ion or molecule attached to a metal atom by coordinate bonding) form the basis for a broad range of biosensor applications. Although these sensing platforms are usually appreciably sensitive and selective, certain drawbacks are associated with biological receptors under non-physiological conditions in terms of temperature, pH, or ionic strength. These limitations have prompted significant research efforts to mimic molecular interactions with synthetic receptors.
Molecular imprinting is the best-known technique to obtain antibody mimics and consists of synthesizing a polymer matrix in the presence of a template species, such as molecules or larger aggregates, with extraction of the template resulting in functionally adapted binding cavities in or on a porous matrix. Although in principle this process is possible, the detection of larger bioparticles, such as proteins, microorganisms, or cells, creates challenges when using the classical molecular imprinted polymer (MIP) concept.
One solution to this challenge being researched extends the concept of molecular imprinting toward surface imprinting, with binding cavities formed directly on the surface of a cross-linked polymer layer in order to facilitate the removal of the templates.
