**4. Emergence of nanotechnology in bacterial pathogenesis**

Nanotechnoly is an emerging field to develop reliable, accurate, cost effective diagnostic method for the detection of infectious agent. In this technology Nano scale particles (1–100 nm) having some novel characteristics such as small size, wide surface area along with some unique structural, electromagnetic, thermal, optical properties. Toxins are not transmitted among the humans as the bacterial infections, but their adverse effect on cell, tissue and other organs urges the scientist to develop the fast, reliable and accurate method of toxin detection. Moreover these toxin persist in environment long time after the death of pathogenic microorganism. Therefor the detection of toxins in the environmental samples are highly significant in the process of intoxication during the pandemic. Various methods such as ELISA, antibody microarrays, antibody-coated polystyrene microbeads, and western blotting etc. used for detection of toxin although these methods are reliable and sensitive but required purified and homogenous samples. Along with these another limitation is the determination of toxins via spectrophotometer or flurometer. To combat this limitation, LC MS liquid chromatography mass spectrometry and MudPIT (multidimensional protein identification), have been used. However, these are highly sophisticated and not user friendly so mostly avoided the broader use of these detection methods [67, 68].

The gold and silver are metallic nanoparticles having electronic and optical properties, coupled with ligands used in chemical sensors. Other gold nanparticles coupled with oligonucleotides used in the detection of cDNA strand [69]. Similarly carbon nanotubes and fluorescent quantum dots widely applied in detection of pathogenic strains, toxins and also detect DNA. Cholera toxins have been detected through molecular mimicry. In this method, the nanoparticles resembled the extracellular matrix of GM1 ganglioside at its terminal portion extracellular matrix which are present in the apex of intestinal epithelial cells and tissues. The UV spectrometer is generally used to detect and quantify the toxins concentration via nanoparticles. The nanoparticles suspension color changes from red to purple within 10 min having the detection limit up to 3 μg/mL. Similarly shiga toxin is also detected by modifying gold nanoparticles and molecular mimicry method. Gold nanoparticles are coupled to globotriose and shiga toxins are interact with these carbohydrate portion of modified nanoparticles that mimicked globotriaosylceramide (Gb3). This Gb3 is present on the renal epithelia and intestinal microvilli [70]. Toxins are recognized by the modified nanoparticles as a result absorption profile is changed, hence these nanoparticles potentially used in biorecognition methods [71].

*An Overview of Bacterial Toxigenesis and a Potential Biological Weapon in Warfare DOI: http://dx.doi.org/10.5772/intechopen.114054*
