Introduction

A biosensor can be defined as a compact analytical device incorporating a biological or biologically derived sensing element either integrated within or intimately associated with a physicochemical transducer. Presently various methods have been used for monitoring of biological and environmental contaminants, for example spectrometric, fluorimetric, gas chromatographic and high-performance liquid chromatographic. These traditional techniques of analysis are extremely powerful in terms of sensitivity, selectivity and specificity, but they poses disadvantages such as the need for expensive equipments, need qualified and specially trained staff and the greatest obstacle is the necessity to carry out extensive pretreatment processes on the sample to be analyzed. Development of alternative analytical devices in Malaysian context, which needs on the spot and real time monitoring device, is very important. Biosensor represents these alternatives, and their application in various fields such as medical, environment and agriculture has been continuously growing in the last years. Under the current scenario of globalization, it is strategically essential that we develop the technical know-how to be able to produce state-of-the-art devices that are competitive technically and commercially in the world market. The implementation of agreements under the World Trade Organization (WTO), Common Effective Preferential Tariff (CEPT) Scheme of the ASEAN Free Trade Area (AFTA) has created greater competition for Malaysian agriculture industry. Main export commodities such as rubber and palm oil face increasing competition from emerging lower cost producers and this will also be applied to other agriculture produce. Thus quality and safety assessment should be developed in order to be more competitive with other countries. Biosensor for food or agriculture produce should be developed in order to face this challenges.

Objective of the project:

The objective of the project is to explore biosensor technologies with the aim of fabricating prototype biosensors based on optical and electrochemical transducers for the detection of specific contaminants such as Phenolic compounds, volatile and nonvolatile pesticides and biogenic amines. These targeted analytes are identified as the major contaminants in environment and agriculture sector in our country.

Status of the research:

A preliminary local made biosensor systems consisting of diamine oxidase (DAO), phenol oxidase and acetyl cholinesterase couples with oxygen electrode and fibre optics were developed and were applied to determine histamines in freshwater prawns, Phenolic compounds in water and pesticide residues in vegetables respectively. The enzymatic reactions occurred were monitored by the Amperometric electrodes and fibre optic detector. The systems that have been studied and developed are still in preliminary stages and more details and fine tuning experimental studies are required to be done in order to integrate the whole system as to produce/fabricate "Malaysian made Biosensor". Each type of studied biosensor system obtained remarkable results. With further research, it is anticipated that such homegrown devices can be commercialized locally and abroad.

Methodology and strategies of the research

The most important aspect of biosensor technology is the fabrication of the bioreceptor-transducer system. The use of various polymer membranes, sol gel and screen-printing in the construction may be the solution to the problem.

 

EXECUTIVE SUMMARY

Project Title:
Development of Biosensor Technology For Detecting Specific
Contaminants in Environment and Agriculture

 

A number of polymers and sol gel could be used as membranes to immobilize biorecognition molecules by physical entrapment or chemical bonding, thus preventing loss and destruction attributed to external factors. In addition to such advantage, some polymers are also compatible with existing thick film-screen printing technology and silicon wafer-photolithography technology.

Beside that the successful commercialization of a biosensor is determined by several factors. Good analytical ability (e.g. specificity, sensitivity, reproducibility, stability etc.) is desired but other characteristics such as durability and manufacturability at low cost are equally important. Durability of a biosensor requires some forms of stabilization of the biorecognition molecules to prevent their destruction and loss. Manufacturability of the biosensor depends on the format of the biosensor and the kind of technology employed in fabrication. Sensor format and fabrication technology that are friendly to manufacturer are likely to be those that are compatible with the existing thick film technology and silicon chip fabrication technology. Using such technologies, biosensors could be mass-produced at low cost.

Development of computer-based instrumentation and development of biosensor structure specifically to detect various analytes mentioned above are the main target and strategy of this research. Various software will be used to control the data flow process and at the same time displaying the biosensor responses in real time.

Research team

The project would be carried out collaboratively with the involvement of multidisciplinary team members from the participating institutions. The team members of this project comprised biochemists, chemists, chemical engineers, electronic engineers and immunologists from various research institutions and Universities such as MARDI, SIRIM, USM, UPM UKM and UiTM. An integrated approach would be implemented to harness the expertise of the team members for successful implementation of the project. Finally National Biotechnology Directorate will fund this project as a Top-Down project.

Period of the project : 3 Years (2001 - 2004)

Achievements

Progress/Achievements for year one

Discovery

1. Development of present design is a success but yet to be tested in real environment due to casing problem. 2. The sol-gel monolith doped with AchE was prepared and composition ratio of (enzyme+ buffer)/ sol was optimized at 3:1. The quantity of enzyme used for the encapsulation was optimized higher than in solution (0.3-0.5 U per assay). Overall, immobilization of enzyme via sol-gel had been done with optimized parameters. 3. Design of sol-gel matrices for chromophore entrapment-Entrapment of the pH sensitive chromoionophore (lipophilic Nile Blue, ETH 5429) was successful and a clear and homogenous film was obtained No leaching of the chromophore was detected Potential in application for optical biosensor incorporating enzymes which convert substrate to acid/base.

Status

- On-going