Detail Project and Funding

Abstract: A biosensor is a measuring device that uses a biologically active surface as a sensitive bio-trasduducer able to transform chemical information on the concentration of a specific component of the sample in an analytically useful signal.
A biosensor is attractive for commercial uses if meets certain basic criteria, as explained in the following.
The analyte must be clearly identified and recognized readily, the detection system must be portable and have rapid response to avoid lengthy and laborious laboratory techniques.
Other important requirements are: easiness to be produced in a large number of samples; user-friendly; cheap; capability to perform simultaneous multiple tests.
There are various single-analyte biosensors for different applications such as: blood measurements (i.e. glucose meters); concentration measurement of hormones, vitamins, etc. into human fluids (eg. pregnancy tests); detection of pathogens.
The success of such single-analyte biosensors had also allowed the development of devices called ‘microarrays’ that contain a large number of different sensors, enabling the simultaneous detection of different analytes.
The collection sites are miniaturized and integrated in a large number on a single substrate, thus reducing time analysis, sample amounts and costs. These micrarray-based biosensors are widely used in different fields such as: medical science (e.g. rapid detection of glucose or of other analytes in human fluids); pathogen detection in environment and food safety.
Another important field of application is for home-land security, namely for reducing the risks related to the biological weapons usually used in terrorist attacks.
Indeed, in this framework, it is easy to imagine how crucial would be the need for rapid, efficient and low cost technique for identifying destruction agents, and therefore for delimitating quickly the potentially contaminated areas.
This project proposes the development of a novel and pioneering portable biosensor to be used as Nano-Bio-Guard for environment and food control and for home-land security, with the aim at detecting in-situ even low concentrated analytes not detectable by traditional methods.
This system will exploit the operating principles of the traditional microarray-based techniques with the innovative aspect of the possibility of concentrating analytes otherwise undetectable.
This will be achieved through the direct release of the analyte through a process of liquid drawing and dispensing named here ‘Pyro-Electro-hydrodynamic’ (in Italian ‘Prelievo-PiroElettroidroDinamico’ P-PED) recently developed at INO-CNR (Naples).
This innovative process is based on the use of pyroelectric fields to generate an electro-hydrodynamic effect able to eject liquid compartments with very low volumes (down to attolitres) from a liquid reservoir (e.g. sessile drops).
This process has been demonstrated to be efficient for printing micro- and nano-droplets and, compared to other
electro-hydrodynamics-based techniques, it provides the fundamental advantage of not having electrodes and external voltage sources neither specialized nano-nozzles.
The concentration effect will be achieved primarily through the collection of very small sample volumes and by the subsequent release of such under-samples onto a highly spatially localized area onto the receiving support.
It is expected that the P-PED process would favour the concentration effect thanks to its ability to collect and release very small volume fractions (down to attoliter).
In particular, the aspect that will be investigated more deeply will be the ability of issuing these villages over an area as localized as possible, according to the detection protocols usually employed in micro-array analysis.
In summary, the Nano-Bio-Guard system will be designed to operate within the following steps:
1) drawing sub-nanolitre volumes of the sample by P-PED;
2) release of the sub-samples onto the biologically functionalized support (even microarray);
3) concentration of the analyte into a highyly localized region of the support;
4) excitation of the fluorophore marker by an appropriate source;
5) detection of the fluorescence signal.
It is therefore expected that the system will consist basically of an interface for the non-invasive and non-contact drawing and dispensing of the liquid sample and of a fluorescence detection interface.
The detection principle will be traditional and based on labelling the anlyte or the probe with the integration into a single monolithic system.
It is important to note that the innovative aspect of the system regards basically the draw-release-concentrate operation step that will be of fundamental importance especially in cases where the analyte is present in low concentrations and therefore requiring time-consuming and laborious processes for concentration enhancement.
On the basis of the above considerations it is easy to imagine the revolutionary implications that, if successful, this project would provide in the field of biosensors for environment and food safety applications.
In fact, it would be possible to have a portable biosensor for Nano-Bio-Guard compact, easy to use (even for unskilled operators) and relatively cheap to provide in-situ analysis for high sensitivity and rapid detection of pathogens.
Such a system would allow to detect analytically complex systems in the liquid, gaseous and solid binary systems consisting of a solid dispersed into a liquid.
The advantages over conventional biosensors and portable ones currently available or in development are manifold.
First, the operation of this system is based largely on principles, processes and components that provide relatively simple methods of implementation.
Moreover it can be made highly compact, portable and inexpensive. In fact, the “drop to array” configuration and the detection of small volumes will allow one to export “lab-on-a-chip” technology out of the laboratory for immediate screening processes.
In particular, it would detect even bacterial or eukaryotic cells. The deployment of the Nano-Bio-Guard system will be possible thanks to the complementary skills and interdisciplinary character of the staff belonging to the two Units INO-INA and IMM-NA.
These skills, in fact, relate to the physics of the process of P-PED, optics and optical diagnostics, integrated micro-optoelectronics, molecular and cell biology, bio-sensors for environmental and food control, thus creating the conditions for a clear synergy of purpose and a realistic chance of success.