Nanoelectronic biosensors for agro-food, environmental, medical monitoring and diagnostics applications

Our health is continuously challenged by infectious diseases, food related toxins, and environmental pollution. The toxin in principle can be organic molecules, proteins, viruses, and bacteria. Protecting ourselves against such threats could be achieved by continuously monitoring their occurrence in strategic positions. In this project several applications are worked out as demonstration models of the potential of nanowire sensor technology^1,2. Specifically we will work on the detection of small organic molecules like mycotoxins from food, and diagnostic proteins from tuberculosis bacteria and Mexican flu viruses. The project at this stage focuses on the measurement of the analytes in relatively clean aqueous solutions of low ionic strength. Reliable extraction protocols will be attended to once a functioning prototype has been developed.

The aim of this project is the development of a self assembled label-free multi-analyte biosensor system utilizing DNA-directed specific immobilization of capture molecules for fast, effective, economical, efficient and reliable detection of contaminants and diseases in process monitoring and diagnostic applications.

In this project until now, we were able to identify and recombinantly produce one of the target proteins present in sputum of infected tuberculosis patient. Antibodies were also raised against this target protein and studies were done on their interaction with the recombinant target protein. Studies on binding kinetics of high affinity antibodies to the target protein were done using surface plasmon resonance measurements.

Currently we are focusing on studying the tertiary structure properties of the target  protein and also busy determining the target protein epitopes which are responsible for interaction with the antibodies. Next, we will link single stranded oligonucleotides to the antibodies using SNAP tag. These DNA-protein intermediates are then used to achieve specific binding of capture proteins on the surface of a nanowire coated with complementary single stranded DNA by DNA-directed immobilization. Finally, surface characterization and initial measurements will be performed using the tuberculosis related receptor-analyte pairs. If successful the developed techniques will be extended to other receptor ligand pairs involving smaller and bigger ligands ranging from organic molecules to viruses and bacteria.

1 A.M. Morales and C.M. Lieber, Science 1998, 279, 208.
2 J. Hu, R.W. Odom, C.M. Lieber, Acc. Chem. Res. 1999, 32 (5), 435.

About the speaker:

Saurabh Kumar Srivastava received a bachelor's degree in Biotechnology (Genetic Engineering) at the Allahabad Agricultural Institute-Deemed University, India. After his bachelor’s degree he has worked at the Department of Biotechnology, in Allahabad Agricultural Institute-Deemed University, India as an lecturer for a period of two years after which he went on to pursue an Erasmus Mundus dual master's degree program in Nanoscience as well as Molecular Bioengineering at the Delft university of Technology and Dresden university of Technology respectively. Currently, he is a PhD student in Laboratory of Organic Chemistry at the Wageningen University and research centre, Wageningen, The Netherlands (WUR), under the supervision of Prof. Dr. Cees van Rijn and Dr. Maarten Jongsma.

His main research interest focuses on the development of nanowire and interdigitated electrodes based biosensor devices for point-of-care diagnostic applications. He also has research experience in recombinant DNA and cloning techniques, characterization and bio-functionalization of thin films for the immobilization of biosensing species on single and/or hybrid surfaces.