Read the paper entitled An integrated semiconductor device e

Read the paper entitled \"An integrated semiconductor device enabling non-optical genome sequencing\" in Nature 2011. Please describe the working principle of DNA sequencing in this work. What is ISFET? How does it work? What is metal-oxide sensing layer used in the work? Describe the advantages and disadvantages using the CMOS For DNA sequencing. Why does increasing salt concentration reduce sensitivity? Explain physically. Please also read the paper \"The potential and challenges of nanopore sequencing\". Write an one-page assay with these two papers, what are pros and cons for each method?

Solution

a) In this setup DNA sequencing process is being performed. First a stimulous in the form of current is directed towards the neuron which produces hydrogen ions. The ISFET is a integrated semiconductor circuit that is sensitive to hydrogen ions, which produces current equivalent to the hydrogennions produced. This current value is converted into an appropriate voltage level using a I-V converter which can be processed using further circuits.

b) ISFET is ion sensitive field effect transistor which is used to measure ion concentration in the solutio. The change in current in the transistor is directly proportional to the change in te concentration of the ions present in the solution.

The whole setup consists of a sensor that senses the ions present in the solution and accordingly produces current that sinks inside the transistor.

c) Metal oxide sensing layer is the layer that senses the current coming from the sensors that detect the ion concentration . The vltage across the metal oxide layer controls the output current of the device.

d) Advantages- The board containing the electronic components reduces the overall the cost of the system and the total output voltage can be integrated with any microprocessor/microcontroller for further processing and analysis. Feasibility to sequence a genome using electronic circuits.

Disadvantages- 20-40% of the sensor produces unyielding results due to poor loading of the chips in IC. Less accurate than the imaging technology.