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Photospectrometric Semiconductor Biosensor

#A-1733


Photospectrometric Semiconductor Biosensor for Prevention of Food Intervention

Tech Area / Field

  • BIO-DIV/Biodiversity/Biotechnology
  • AGR-DIS/Disease Surveillance/Agriculture
  • AGR-FOD/Food & Nutrition/Agriculture
  • BIO-SFS/Biosafety and BioSecurity/Biotechnology
  • CHE-RAD/Photo and Radiation Chemistry/Chemistry
  • ENV-APC/Air Pollution and Control/Environment
  • MED-DID/Diagnostics & Devices/Medicine
  • MED-DIS/Disease Surveillance/Medicine

Status
3 Approved without Funding

Registration date
18.03.2009

Leading Institute
National Polytechnical University of Armenia, Armenia, Yerevan

Collaborators

  • Seconda Universita degli Studi di Napoli / Dipartimento di Medicina Sperimentale, Italy, Napoli\nWageningen UR, The Netherlands, Wageningen\nUniversity of Montreal, Canada, QC, Montreal\nPhotonics Laboratories, Inc., USA, PA, Philadelphia\nPolitecnico di Milano / Dipartimento di Ingegneria Strutturale, Italy, Milan\nUniversity of South Florida / College of Engineering, USA, FL, Tampa\nAston University, UK, Birmingham\nMarshall University, USA, WV, Huntington\nPolitecnico di Bari / Dipartimento di Elettrotecnica ed Elettronica, Italy, Bari

Project summary

The aim of the project is to develop a reliable portable optical sensor for the studying of nano-biosystems and ecological conditions of the environment. The sensor will be based on a new type of photospectrometer. The technical realization of the unique physical principle that is technologically and constructively designed into the photospectrometer will allow us to select and register informative radiation from the integral flow of radiation coming from the object with an accuracy of < 0.1 nm of wavelength.

There is an urgent need for the development of portable optical sensors for measuring small spectral composition changes, for the selective (with accuracy < 0.1nm) registration of the spectral intensity of radiation (based on their natural behavior and their response to specific excitation).

The necessity to identify on a molecular level such species as DNA, proteins, mycotoxins, enzymes or biological membranes, cells and tissues, as well as the need to study the specific character of bio molecular interactions non-invasively underlines the value of optical spectroscopy of biological objects that gives information on electron transitions in specific organic molecules thus providing molecular recognition of bio-cells. Such molecular recognition allows one to study the molecular specificity of cellular interactions that plays a key role in nanobiology including adhesion, aggregation and tissue formation as self-correlating systems.

Although the UV/Vis spectroscopy of biomaterials and space signals provides rather precise and reasonable data of radition with low intensity, the information obtained by means of the novel semiconductor photospectrometer proposed here will be unique because it will make the analysis of signals more precise, reliable, efficient and cheaper. The on-line data visualization of informative radiation will allow the usage of multivariate data analysis via measuring wavelengths and radiation intensities in narrow spectral regions, and to provide monitoring of biochemical and biophysical processes in real time.

The informative radiation can be the result of a reflection from the biomaterial deposited on the films of porous silicon (PSi) or the result of transmission through the biomaterial after partial absorption. The change of the composition and of the number of bio-species leads to a change in the absorption or reflection of the electromagnetic radiation in the spectrum. It may result in a shift of the spectral line or of spectral peaks due to the presence of specific impurities or because of changes in their concentration.

Currently approaches applied to spectrophotometric biosensors are based on the use of PSi films and silicon photodetectors. Theoretical and experimental studies showed that PSi nanostructures are universal platforms for chemical and biological sensing due to their favorable morphological and physical properties. Unfortunately, the PSi surface is highly hydrophobic and treatment is required to ensure the stability of the surface and allowing the bio-probe to bind covalently. This creates additional difficulties. As to the use of current photodetectors, their main disadvantage is the lack of spectral selectivity.

This project is truly unique because for the realization of the specified plans we, based on many years’ of relevant experience and knowledge, aim to develop a silicon photospectrometer operating on a new physical principle. The photospectrometer will allow us to perform selective registration of informative radiation of submicron wavelengths from the integral flow of radiation coming from the biomaterial with an accuracy of < 0.1 nm and operation speed ~10-10 s. Optical sensors like this may potentially replace spectrophotometric devices and monochromators from applications in related areas because the use of current hardware makes measuring devices more costly and less efficient.

Thus, we propose a new type of selective photodetector which will advance the solution of the selectivity problem of the spectral analysis without the use of expensive filters, will raise the measurement accuracy and reduce the material consumption for the fabrication of the sensor.

For efficient high-accuracy registration of narrow spectral bands or specific wavelengths we will use the high-tech semiconductor material – silicon, and on its base we will develop a structure with two oppositely directed potential barriers. The compensation degree of oppositely directed photocurrents conditioned by these barriers will depend both on the external voltage and on the wavelength of the absorbed radiation. By means of a designed automated portable software system it should be possible to modify these parameters and obtain high-accuracy information on processes occurring for investigating objects on a special mini-screen. The system will include a device for housing the investigating bio-probe and by a small-sized source of integral electromagnetic radiation with required intensity and spectral range.

The functions of the device will define the target issues we aim at: optical selection, communication with the computer of submicron optical signals, optical integration, and optical detection.

We contend that our approach may find an application in various fields: studying of nanobiosystem, solution of ecological problems by means of UV monitoring of the environment and climate change, pharmaceutical production, detection of dangerous mycotoxic contaminants in food and provender in natural conditions, and, in other areas which are considered to be strategically important in industrially developed countries and require the constant improvement of methods, means and tools.

Particularly, just the use of portable bio-sensors for the timely detection of mycotoxins in raw materials would significantly reduce the risks of contamination of ready products by mycotoxins, and would greatly help the livestock farming (poultry farming, aquaculture) that suffers large losses because of the use of contaminated food. It should be noted that for a number of countries such as India, the Philippines, Australia and others, the economic losses caused by the contamination of primary products (peanuts, coffee, corn and other cereals, spices) exported from those countries reach $470 million a year.

The research work will be the product of the joint cooperation of the specialists from of five research organizations of Armenia (Research Institute Plast Polymer, Industrial Park "Viasfer", Institute of Radio Physics and Electronics of National Academy of Science of Armenia, Yerevan State University and SEUA). The ultimate goal is the implementation of device proposed here into the industrial sector of Armenia.

We would be happy to consider any other possible applications that may attract worldwide attention and have great potential based on the scalability of processes on the basis of silicon.

To achieve the aims of the project we have assembled a team of highly qualified specialists and technical experts. Together with foreign collaborators they will provide the implementation of the innovative competitive product.

Many of the staff members are the leading international researchers in their fields. Particularly, they are participants of projects ISTC А - 431, А - 544, A-359, A-948, A-1353, A-1243.2, FARA-USDA – 2003,2004, FP6/7 – 2006-2007 - «InJoy&Train». The participants have already:

  1. introduced constructive-technological solutions for increasing the efficiency of the registration of the integral flow of radiation in silicon photoreceivers;
  2. designed models of silicon high-performance converters with quantum wells on the basis of nanostructures;
  3. designed models of semiconductor resonator photostructures for selective registration of optical radiation;
  4. developed vinyl acetate homopolymer films for different types of membranes of bio-cells;
  5. developed express methods of microorganism detection.

The main objectives and deliverables of the proposed project are:
  • Development of a new type of photospectrometric photodetector for the UV and visible spectrum which will select and register the required spectral channel within the range of wavelengths 0.2 – 0.66 μm with accuracy < 0.1nm. The spectral sensitivity control will be carried out by external voltage within -0.5 – 0.5 V. Dark currents will not exceed 10-13 А/сm2, and operation speed will be ~10-10 sec
  • Mathematical modeling of the electronic processes of a compact inexpensive semiconductor photospectrometer. Development of its optimal design and fabrication technology
  • Development of an automated information gathering and processing system, and the storage of information received from bio-objects
  • Fabrication of a portable optical biosensor, its testing on a biomaterial
  • Price reduction and facilitation of the processes of photospectrometric analysis of biomaterials, foodstuffs, environment, etc.
  • UV monitoring of the environment and the assessment of ecological conditions.

The overall aim of this proposal is to develop a step change capability by designing a portable optical sensor and a study carried out on a specific biological object, particularly in the field of detection of economically important mycotoxins such as aflatoxin B1 and aflatoxin M which possess absorption and natural fluorescence in the UV area.

It is planned to use the portable optical sensor developed within the framework of this project in Armenia, and to promote its further use in other countries for facilitating the accurate studies of processes occurring in biomaterials, and for timely detection, for instance, of mycotoxins in food, raw materials and provender, as well as for UV monitoring of the environment for sustainable development.


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