Recently the word environment has been acquiring a broader meaning. Prevention, monitoring, and depuration are now focused not only on the chemical detection of air, water and soil pollutants but also on the health of the ecosystem, quality of life, including not only man but all living beings, clinical diagnostics and food safety, industrial activities and products, effects from chemical, biological and physical agents.
In this sense the need for controls of such a complex environment reflects the request for an increased measurement ability, mainly in terms of number of analyses and costs but also in terms of knowledge of the relationship between causes and effects.
Genetically modified organisms (GMO) and microorganisms (GMMO), for new processes and products in the field of agriculture, food and therapy (new drugs and vaccines), represent new challenges but also a potential risk for the sustainable progress of mankind. However, they have to be well known and controlled, to rule out their possible negative effect on health and biodiversity.
For these reasons, the use of sensor-based analytical methods, originally focused on chemical and biochemical tests, is gaining increasing interest in the fields of environmental toxicity testing, for ecosystem monitoring as well as testing of crops and foods of animal origin, clinical diagnosis and therapy. The increased interest in sensor–based techniques is proven by the significant number of both scientific papers and registered patents on this subject. Multidisciplinarity between chemistry, material sciences, biochemistry, molecular biology, physics, μ-electronic technologies, and engineering has created important new ideas in several research fields, including biosensing and remarkable results for improving quality of life on our planet can be expected.
Increasing number of potentially harmful pollutants in the environment calls for fast and cost-effective analytical techniques to be used in extensive monitoring programs. In this context, biosensors appear as a suitable alternative or a complimentary analytical tool. In spite of having many advantages, many of the developed systems cannot compete with conventional analytical methods. Strict requirements of application of most traditional analytical methods to environmental pollutants analyses constitute an important hindrance for their application on a regular basis.
Anyway biosensors can be used as environmental screening tools in the assessment of biological/ecology quality or for the chemical monitoring of both inorganic or organic pollutants:
As a matter of fact biosensors represent a technology, which is intended for mass production of hybrid devices based on the so-called “smart properties” of natural molecules and technological materials. Biosensors result by coupling a biological part (proteins with enzyme activity, receptors, nucleic acids, but also living cells or tissues) which is able to selectively recognize the analytes or a class of analytes and a transducer to convert the chemical signal in a readable and recordable electrical signal.
At the moment few engineered biomolecules and nanostructured materials are used for commercially available analytical devices and the critical factors for their use are mainly related to their stability and optimal (oriented) immobilisation, without loss of functional properties. On the contrary an amazing number of papers and researches were done for coupling the smart properties of new biologically engineered molecule and microorganisms with technological nano-sized materials.
Hybrids, synthetic, natural molecules, including their active fragments or modified derivatives, have been used. Genetically engineered biomolecules seem to be a new and powerful approach for obtaining simpler artificial structures with intact or improved properties (stability, sensitivity and specificity) or with additional functional groups and activities. For example, a His6 tag can be used for oriented and reversible immobilization of engineered single-chain antibody fragments (scFvs), or gene fusions with phosphatases or green fluorescence protein may allow analytical detection using bacterial cells.Recombinant bacterial systems have been used to monitor environmental benzene contamination based on engineered Escherichia coli, which carries genes coding for benzene dioxygenase and benzene dihydrodioldehydrogenase from Pseudomonas putida. These activities can be detected electrochemically or colorimetrically and used to monitor benzene pollution in environmental air samples. Nanostructured materials have proven to be a powerful tool in new technologies as well as in basic research, due to their very peculiar properties at nanometer size scale. Many studies and publications have demonstrated that optical, mechanical, photo-catalytic or electronic properties of the nano-sized surfaces drastically change with respect to those of the bulk materials. Electrochemical biosensing constitutes a research field where nanotechnologies have been successfully applied, especially in using nano-sized materials with high surface to volume ratio as well as metal wires and tubes, carbon nanotubes or graphene. The synthesis via template represents a convenient procedure, which in many cases has strongly simplified the production of surface confined nano-scale materials as nanoparticles, nanowires or nanotubes (nano-electrode ensemble). This method is essentially based on the simple but effective idea that the pores or cavities of the host supports can be used as templates to address and control the growth of specific materials, i.e. metals, semiconductors, biological compounds and polymer chains. The use of templates in producing novel nano-materials goes back to the early eighties. Pioneering works were ascribed to authors involved in the preparation of different metallic nanostructures but presently the method was extended to a large number of substrates and applications. Advances in biotechnology and nanotechnology may be able to provide more sensitive and stable detection systems for air and water quality monitoring, allowing the simultaneous measurement of multiple parameters and real time response capability.
Disclaimer: These pages solely reflect my own personal opinion and