A portable, sensor-based, eco-friendly device that can detect key biomolecules such as bovine serum albumin (BSA) is being developed at the Indian Institute of Technology-Hyderabad (IIT-H).

IIT-H researchers have filed for a patent on their sensor for the BSA protein. The research has been published in the journal Scientific Reports by Suryanarayana Jammalamadaka, Department of Physics, and research scholar Dwipak Prasad Sahu.

Suryanarayana said, “Several methods, such as spectroscopy, immunoassays and chromatography, are used to assess the concentration of BSA. They require special testing equipment, which requires skilled operators and delayed diagnosis.”

The IIT-H scientists decided to develop a sensitive, rapid and inexpensive method for the quantitative analysis of BSA, which would lead to faster and cheaper diagnostics, he added.

Human serum albumin (HSA) has been of great interest, and assessment of its level in human blood and urine is important in the diagnosis of a range of conditions such as malnutrition, kidney diseases and liver abnormalities.

In medical diagnosis, detection and quantification of albumin proteins are important. Albumin essentially carries vitamins, enzymes and hormones throughout the body. It also helps maintain the nutritional balance.

However, due to the structural similarities of BSA and HSA, BSA has been used as a model protein in the research fields.

Explaining the research work, Suryanarayana said, “We have developed a memristor to detect BSA. The memristor or Resistive Random Access Memory (RRAM) is a device that can change its resistance state by changing the voltage. The switching from high resistance state to low resistance state with voltage is called SET switching and the reverse is RESET switching.”

The Memristor consists of two terminals and the active material that is sensitive to the protein is sandwiched between two metal electrodes that are connected to the terminals. The IITH team used titanium dioxide (TiO2), a white powder that is commonly used in cosmetics and sunscreens, as the active material. Silver was used as top electrode and fluorine doped tin oxide (FTO) was used as bottom electrode.

When the active material (TiO2) came into contact with BSA, there was a lowering of voltage pertinent to SET switching. To improve sensitivity of material to detect BSA, they coated a layer of graphene dioxide on TiO2.

“We have also tested our device for its durability and found that the device performed reliably continuously 650 times. All the materials used in the sensor are also environment friendly, cheap & biocompatible, said Suryanarayana.

The next step is to make a portable device, he added.

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