**4. Nanobiosensor application in food**

*Novel Nanomaterials*

**3. Nanobiosensor**

of signal detection (**Figure 1**).

methods for quality control [28, 29].

**200**

**Figure 2.**

*D: Diameter [35].*

*Commonly used nanomaterials in various kind of sensors fabrication with their sizes. L: length;* 

By using of the transducer, mainly it is divided in to three types, those are, 1.

Biosensors especially nanobiosensors can overcome all the disadvantages of conventional detection methods by offering a rapid, non-destructive and affordable

Biosensors are synthesized using nanomaterial is called nanobiosensor. This type of biosensor can able to detect the changes happen in the atomic level with more accuracy. In normal biosensor s receptor and transducer materials are made up of normal micro and macro sized material, but in nanobiosensor either receptor or transducer or both are made up of nano material i.e. at least any one dimension is less than 100 nm [30, 31]. Nanomaterials are very small size, so it is having unique physical, mechanical, optical, electrical and magnetic characters when compared to the conventional material. This is the added advantage of the nanobiosensor and reason for all the superior sensing qualities. Researchers have used various nanomaterials and nanocomposites to enhance the sensitivity, shelf life and get the precision in the biosensing results [32, 33]. Mostly four types of nanomaterials i.e., carbon based, metal based, polymer based and nanocomposites are used for various field application [34]. Perhaps among four, dendrimer is not used that much as frequently as other nanomaterial in the bio sensing field. Carbon nanotubes (CNTs), quantum dots (QDs), gold (Au), silica, silver (Ag), graphene and other nanocomposites are synthesized in such a way having large surface area to volume ratio to improve electrochemical parameters (**Figure 2**). The molecular binding is a subject of the biological surface science, which is strongly related to the research on modification of nanostructures properties by controlling their structure and surface

In these major types is divided in to many subtypes based upon the mechanism

Electrochemical, 2. Mass based and 3. Optical Biosensor.

Harmful microorganisms such as pathogenic bacteria, viruses, or parasites and its toxin and excessive use of agrochemicals (pesticides, herbicides and food preservative) are the common causes of food contamination. The primary contaminants leading to foodborne illness are pathogenic microorganisms including: *Bacillus cereus, Clostridium botulinum, Escherichia coli (E. coli), Listeria monocytogenes, Salmonella* and *Staphylococus aureus* [40]. Currently, there are limited methods for field detection of toxins and foodborne pathogens, making early identification of a possible contamination is much difficult because of the low efficient conventional methods. The biosensors integration with various nanostructures like thin films, nanorods, nanoparticles and nanofibers, in the analysis methods for detection of food contaminants has improved the detection sensitivity and increased portability. In food microbiology, nanosensors or nanobiosensors are used for the detection of pathogens in processing plants or in food material, quantification of available food constituents, alerting consumers and distributors on the safety status of food [26, 41].
