**3.5 Atomic force microscopy (AFM)**

Atomic force microscopy (AFM) offers ultra-high resolution in particle size measurement by physically scanning samples at the sub-micron level with an atomic probe tip. Based on forces between the tip and the sample surface, the instrument generates a topographical map of the sample [15]. Depending on the qualities of the sample, it is usually scanned in contact or non-contact mode. In contact mode, the topographical map is created by tapping the probe across the sample surface, while in the non-contact method, the probe hovers over the conducting surface. The ability to image non-conducting samples without special treatment is AFM's main advantage, allow ing imaging of delicate biological and polymeric nano and microstructures. The most accurate description of size and size distribution is provided by AFM, which

*Bacterial Silver Nanoparticles: Method, Mechanism of Synthesis and Application in Mosquito… DOI: http://dx.doi.org/10.5772/intechopen.104144*

does not require any mathematical treatment. Furthermore, the AFM technique provides a realistic picture of particle size, which aids in understanding the impact of diverse biological circumstances [19].

#### **3.6 X-ray diffraction**

XRD is one of the most common analytical techniques for phase identification and crystalline structure determination in solid-state materials. To determine the structure of a molecule, X-rays focused on constrictive use of destructive interference caused by scattering radiation from a single crystal's regular and repeating lattice [19].

#### **4. Nanotechnology in mosquito control**

The life of mosquitoes is intertwined with human life, and they have been a significant factor in human society for many years. Although they have been recognized as criminals for hundreds of years, their nuisance has not diminished. We have been suffering from the effects of mosquitoes since the beginning of humankind. These cause hundreds or more diseases against the human race. Millions of people have died as a result. Although, the elimination of mosquitoes is octagonal. Even though various countries have implemented many health promotion programs against mosquitoes, it is still a significant problem globally. Mosquitoes transmit dangerous diseases known to humans, such as malaria, yellow fever, dengue, encephalitis, filariasis. More than 3500 species have been recorded worldwide across five continents. Mosquito-borne diseases, such as malaria, arboviruses, and filariasis, and their vectors are present worldwide [20].

Mosquitoes are severe vectors of critical human parasites and microbes. *Culex quinquefasciatus* is a domestic mosquito that thrives close to human activities and habitation. West Nile virus, St. Louis encephalitis, and lymphatic filariasis are among the pathogens *Cx. quinquefasciatus* can transmit to humans and animals. *Cx*. *quinquefasciatus* can transmit pathogens such as avian malaria and zoonotic dirofilariasis to livestock, birds, domestic and wild animal species, resulting in loss of productivity and death. *Cx. quinquefasciatus* is also a nuisance because its bites can cause local dermatitis or acute systemic allergic reactions in many people [21].

There is no aquatic habitat anywhere; it does not lend itself to being a breeding ground in the world for mosquitoes. They are temporary and permanent colonial, very dirty and clean, big and small waters, even the most miniature accumulation buckets filled with water, flower vases, tires, hoof, etc., possible sources of prints and leaf axes. Flood mosquitoes in temporarily flooded areas, rivers, or lakes with water fluctuation *Aedes vexans* or *Ochlerotatus sticticus* formed in large numbers and within a range of miles. They can become a significant nuisance even in places far away from their breeding grounds.

Many methods are used to control the mosquitoes, but they have disadvantages; chemical control was one of the most widely used conventional methods for mosquito control [20]. Since chemical pesticides are relatively inexpensive, they usually produce immediate control. Generally, the chemical control is carried out by the indoor residual spraying of insecticides such as DDT, organophosphates, chlorpyrifosmethyl, fenthion, fenitrothion, malathion, pirimiphos-methyl, temephos, carbamates bendiocarb, propoxur, pyrethroids alpha-cypermethrin, bifenthrin, cyfluthrin, cypermethrin, deltamethrin, etofenprox, lambda-cyhalothrin, permethrin, hexachlorocyclohexane, benzene hexachloride, malathion, and synthetic pyrethroid. However, the development of resistance against these chemicals in various mosquito populations has been reported [20]. Therefore, biological control can provide a practical and environmentally friendly approach that can be used as an alternative to reduce the number of mosquitoes. Microbially mediated AgNPs are powerful tools for combating mosquitoes and agricultural insects [20].

Marimuthu et al. [22] reported that synthesized metal nanoparticles derived from *B. thuringiensis* showed remarkable larvicidal activity against *A. subpictus* and *A. aegypti*. Similarly, AgNPs obtained from *B. thuringiensis* (Bt) and *F. oxysporumculture* filtrate showed strong larvicidal activity against *A. aegypti*, *A. stephensi* and *C. quinquefasciatus* mosquitoes [23]. In addition, several studies have reported that the bacterial strains of *L. monocytogenes*, *B. subtilius*, and *S. anulatus*-mediated AgNPs showed larvicidal activity [24]. The *Pseudomonas aeruginosa* synthesized Ag NPs were treated against *Cx.quinquefasciatus* and showed a higher susceptibility to the synthesized AgNPs and showed that 100% mortality was observed after 1 hour of incubation [25].
