Patterned live neural networks by induced electrical fields for bio-sensing

It is estimated that about 18 million people worldwide suffer from dementia and it is projected to increase to about 35 million by the year 2025. All types of dementia occur due to an aberration in memory retention and development, caused by malfunctioning neurons. Experimental investigation of the dynamics of biological networks is a fundamental step towards understanding how the nervous system works. Activity-dependant modification of synaptic strength is widely recognized as cellular basis of learning, memory and developmental plasticity. Understanding memory formation and development, thus translates to changes in the electrical activity of the neurons. It is not possible to achieve this understanding at a cellular level by in vivo studies. To map the changes in the electrical activity it is essential to conduct in-vitro studies on individual neurons. Hence there is an enormous need to develop novel ways for assembly of highly controlled neuronal networks. To this end, we used a 5x5 multiple microelectrode array system to spatially arrange neurons, by combination of applied DC and AC fields We characterized electric field distribution inside our test platform by using two dimensional finite element modeling (FEM). As the first stage in the formation of a neural network dielectrophoretic AC fields were used to position the neurons over the electrodes. We used DC electric field to control axon growth direction within the network. Applied electric field direction is found to be an important parameter for axon growth. Electrical impulses were recorded from the individual neurons in the network during positioning and network formation.