**5. Topnotch favored approaches**

Pulsed Laser Ablation in Liquid (PLAL) subordinated to physical methods is the top-notch method for producing Ag NPs since it is a green method which utilize the least time & finances [48, 49]. Because of nucleation, advancement & cluster formation, it is a subordinate to the bottom-up process. Interacting with ultrashort laser beam pulses i.e., 13 8 10 10 sec − − *to* , generates nanostructures from the metal bulk substrate in any medium, is called a laser ablation process [32, 50, 51]. It depends on aspects like laser wavelength (λ), repetition rate, frequency, pulse duration, the light absorption efficiency of material, transmission, and chemical composition of the liquid. The monochromaticity and directionality of the laser beam are vital characteristics for this process.

Moreover, produced Ag NPs are pure and are free of metal colloids contamination and have great quality because of non-utilization of any artificial or natural surfactant. Efficiency and features of produced Ag NPs are based on specifications, consisting of "λ", pulse duration, ablation time & the laser beam interaction with each NP inside the liquid [52, 53]. Spatial profiling of laser beam intensity or fine balancing of "λ" controls size distribution [54]. Essential specifications are briefed be/neath:

• *Pulse Duration*: In PLAL it can vary from *Femto-Nano* seconds. NPs originated via sputtering of the molten surface layer by the liquid's recoiling pressure around the processing metal. The temperature *"T"* of the laser beam spot is denoted with simple heat balancing equation:

$$T \approx \frac{Aj}{cph} \tag{1}$$

Here, A - absorptivity of marked material (A **=** 1- R) [R - reflectivity coefficient].

c - heat capacity of marked material,

ρ - density of marked material,

h - heat diffusion length inside marked material,

The heat diffusion length *"h"* is dependent on the heat diffusivity of the processed sample, expressed as:

$$h \propto \sqrt{at\_p} \tag{2}$$

**115**

**Table 2.**

*\* Nanosecond \*\*Femtosecond \*\*\*Nanometer \*\*\*\*Milliliter.*

**Figure 5.**

*Silver Nanoparticles - Preparation Methods and Anti-Bacterial/Viral Remedy Impacts…*

In PLAL, laser beam is directed to a processing sample top-layer plunged into liquid. Supposedly, because of transparency and non-absorption of liquid, the laser beam radiation can focus directly on the target. The ideal facade of the liquid avoids surplus reflection at the interface "covering glass/air". However, the use of unstable liquids like acetone, ethanol, etc., demands covering the vessel with a

The laser ablation is successful only when tiny structures of processed metal are constructed by PLAL, see **Figure 5** [55]. In **Figure 5**, an *Ag* sample is immersed in distilled water and is synthesized under pulsed laser. Different types of lasers like Solid, Gas or chemical laser, can be used with distinct "λ" ranging from picofemtosecond. Generated NPs have extraordinary features and are irreproducible by

**Figure 5** demonstrates the Ag NPs generation out of a bulk silver plate via high-power pulsed lasers in PLAL. Material properties affect the ablation at its best. Various laser parameters are used to composite NP characters like size, shape, surface properties, aggregation state, solubility, structure, and chemical

• The generation efficiency & the size of colloidal components of *"ns"* laser was

• The manufactured colloids by *"ns"* pulses were extra scattered than *"fs"* pulses.

*Diagrammatic representation of PLAL process with metal immersed in distilled water [54].*

**Laser Type** Nd: YAG (ns\*

**Quantity & Type of Liquid** 170 ml\*\*\*\*

**Wavelength** 532 nm 800 nm 1064 nm

**Mean Diameter of NPs** 2–3 nm\*\*\* 400 nm\*\*\* 2–5 nm\*\*\* **Absorbance** 0.28 > 0.05 < 0.1

(Pure water)

*Different laser parameters for obtaining Ag NPs via PLAL, based on the theoretical research [57–59].*

) Ti: Sapphire (fs\*\*) Nd: YAG (ns\*

5 ml\*\*\*\* (Deionized water) )

25 ml\*\*\*\* (Pure water)

*DOI: http://dx.doi.org/10.5772/intechopen.99368*

any other traditional methods [56].

composition, see **Table 2** [30]. When compared,

larger than *"fs"* laser.

transparent lid [54].

wherein, <sup>k</sup> a <sup>c</sup> <sup>=</sup> , [*k* - heat conduction coefficient of marked material & *" <sup>p</sup> <sup>t</sup> "* - laser pulse duration].

Larger the *<sup>p</sup> t* , bulky is the layer of material which is heated by laser energy absorption. Moreover, for heating & evaporation of liquid adjacent to the laser beam spot, an unwanted bulk of energy is drained approximate to the one absorbed due to reduced thermal conductivity of liquids [54].


*Silver Nanoparticles - Preparation Methods and Anti-Bacterial/Viral Remedy Impacts… DOI: http://dx.doi.org/10.5772/intechopen.99368*

In PLAL, laser beam is directed to a processing sample top-layer plunged into liquid. Supposedly, because of transparency and non-absorption of liquid, the laser beam radiation can focus directly on the target. The ideal facade of the liquid avoids surplus reflection at the interface "covering glass/air". However, the use of unstable liquids like acetone, ethanol, etc., demands covering the vessel with a transparent lid [54].

The laser ablation is successful only when tiny structures of processed metal are constructed by PLAL, see **Figure 5** [55]. In **Figure 5**, an *Ag* sample is immersed in distilled water and is synthesized under pulsed laser. Different types of lasers like Solid, Gas or chemical laser, can be used with distinct "λ" ranging from picofemtosecond. Generated NPs have extraordinary features and are irreproducible by any other traditional methods [56].

**Figure 5** demonstrates the Ag NPs generation out of a bulk silver plate via high-power pulsed lasers in PLAL. Material properties affect the ablation at its best. Various laser parameters are used to composite NP characters like size, shape, surface properties, aggregation state, solubility, structure, and chemical composition, see **Table 2** [30].

When compared,

*Silver Micro-Nanoparticles - Properties, Synthesis, Characterization, and Applications*

Pulsed Laser Ablation in Liquid (PLAL) subordinated to physical methods is the top-notch method for producing Ag NPs since it is a green method which utilize the least time & finances [48, 49]. Because of nucleation, advancement & cluster formation, it is a subordinate to the bottom-up process. Interacting with ultrashort laser beam pulses i.e., 13 8 10 10 sec − − *to* , generates nanostructures from the metal bulk substrate in any medium, is called a laser ablation process [32, 50, 51]. It depends on aspects like laser wavelength (λ), repetition rate, frequency, pulse duration, the light absorption efficiency of material, transmission, and chemical composition of the liquid. The monochromaticity and directionality of the laser

Moreover, produced Ag NPs are pure and are free of metal colloids contamination and have great quality because of non-utilization of any artificial or natural surfactant. Efficiency and features of produced Ag NPs are based on specifications, consisting of "λ", pulse duration, ablation time & the laser beam interaction with each NP inside the liquid [52, 53]. Spatial profiling of laser beam intensity or fine balancing of "λ" controls size distribution [54]. Essential specifications are briefed be/neath:

• *Pulse Duration*: In PLAL it can vary from *Femto-Nano* seconds. NPs originated via sputtering of the molten surface layer by the liquid's recoiling pressure around the processing metal. The temperature *"T"* of the laser beam spot is

<sup>≈</sup> *Aj <sup>T</sup>*

The heat diffusion length *"h"* is dependent on the heat diffusivity of the pro-

Larger the *<sup>p</sup> t* , bulky is the layer of material which is heated by laser energy absorption. Moreover, for heating & evaporation of liquid adjacent to the laser beam spot, an unwanted bulk of energy is drained approximate to the one absorbed

• *Laser Wavelength*: As most of constructed NPs can consume laser radiation (which can melt material), so, UV ranging "λ" are least preferred in

• *Repetition Rate*: With every laser pulse, NPs are discarded from the processing sample surface. Therefore, higher the repetition rate of laser pulses, higher is

<sup>c</sup> <sup>=</sup> , [*k* - heat conduction coefficient of marked material & *" <sup>p</sup> <sup>t</sup> "* - laser

Here, A - absorptivity of marked material (A **=** 1- R) [R - reflectivity

*cph* (1)

*h at* ∝ *<sup>p</sup>* (2)

**5. Topnotch favored approaches**

beam are vital characteristics for this process.

denoted with simple heat balancing equation:

h - heat diffusion length inside marked material,

due to reduced thermal conductivity of liquids [54].

c - heat capacity of marked material, ρ - density of marked material,

cessed sample, expressed as:

wherein, <sup>k</sup> a

PLAL [54].

the NP production [54].

pulse duration].

**114**

coefficient].


#### **Figure 5.**

*Diagrammatic representation of PLAL process with metal immersed in distilled water [54].*


#### **Table 2.**

*Different laser parameters for obtaining Ag NPs via PLAL, based on the theoretical research [57–59].*


## **6. Nosocomial epidemic (hospital-acquired infections)**

The predominating threats in the biomedical line are the penicillin-immunity of the living beings, product advancement behavior and its services in terms of hazardous, healing timespan & aftereffects on the mortal cells. Also, the revelation of infection-inducing non-bacterial microorganisms, supervising infection administration & avoiding nosocomial infections (**Figure 6**) are main confronting puzzles for the science [61].

A survey by WHO concluded that moderately 8.7% of world population has suffered from nosocomial disease, and approximately 1.4 million people suffered Hospital-Acquired Infections (HAI) [62]. Eastern Mediterranean & southeast Asian regions are HAI sensitive rather than the other regions. Nosocomial Infections covers categories likes surgical wounds, urinary & lower respiratory tract infections. The latter was particularly pronounced for the 2020 COVID-19 infections.

Avoidance of HAI demands a coordinated & overseen plan in which peculiar features must be calculated. The transmission of bacterial/viral microorganism from person to person is diminished by individual cleaning like handwashing, hand gloves, masks, working clothes, shoes, & sterilization of medical apparatus [63].

Also, higher the bacterial/viral protection, higher is the impact on wellbeing. Many theories have been executed worldwide for restricting HAI's. It is noted that Ag NPs utilization is highly emerging solution to quarantine the Nosocomial Infections, also, an efficient nano-weapon to multidrug resistance microorganisms [64].

The unmanaged & enormous use of penicillin and their bacterial hostility is a present-day menace for medicinal industry, which also consists of Ag NPs induced antibiotics [65]. Ag NPs obtained from bio-methods using *B. marisflavi* resulted high antibacterial actions against bacteria leading to nosocomial infections [66].

In therapeutic institutions, medical apparatus is the usual source of spreading infection. The quick fix to this problem could be the coating apparatus with Ag NPs to bypass bacterial contagion. Ag NPs are productively utilized in catheters

**117**

**Figure 7.**

*Demonstrating antibacterial features of silver nanoparticles.*

*Silver Nanoparticles - Preparation Methods and Anti-Bacterial/Viral Remedy Impacts…*

titanium instruments is modified by UV light exposure [68].

tions should be taken to avoid their noxious impact on humans.

for enhanced antimicrobial actions & zero thrombogenicity [67]. The writers also questioned the impact of Ag NPs on blood clotting, and the outcomes are fascinating. It should also be understood that the antimicrobial impact of Ag NPs coated

Exploration in this branch had concluded an overall bacterial termination of Methicillin-resistant *staphylococcus aureus* (MRSA) as a result of Ag NPs synergic effect as a photocatalyst & visible light was accomplished [5, 69]. An identical energetic bactericidal effect was detected with stents & catheters used in cardiovascular operations [70]. So, it can be believed that the Ag NPs are advantageous ingredient to isolate differential ailments occurring in therapeutic organizations. Also, precau-

Many researchers have examined & published the antibacterial performances of Ag NPs. The bacterial cell membranes consist of sulfur (S) comprising proteins & involves amino acids. On inner & outer membrane Ag can blend in with them preventing bacterial expansion. Ag NPs also produce Ag ions which blends in with Deoxyribonucleic acid's (DNA's) phosphorus (P) and with *"S"* consisting of proteins, inhibiting the enzymes movement. Characteristics like "size" & "shape" of NPs guides to evaluate Ag NP's antimicrobial behavior. NPs of size <20 nm will execute a better attachment of *"S"* comprehending protein of membrane ending in cell death of bacteria as a result of maximum permeability via membrane [71]. **Figure 7** represents the interaction mechanism of Ag NPs surface-to-volume ratio on bacteria/virus. Nanomaterials has a nature, that smaller the NPs, greater surface interaction is exposed and contributes to better microbicidal effect [72, 73]. Shape of NPs also plays avital role to interact with the membrane walls. Analysis

in [74] directs to large anti-activities towards *E. coli* bacteria with abbreviated triangles of Ag NPs better than those of spherical & rod-shaped NPs. It is also mentioned that Ag NPs <10 nm creates holes in the cell wall as a result of these holes the cytoplasmic is dispensed into the medium, responsible for controlling cell death without interaction between intracellular and extracellular proteins and bacterial nucleic acids. The writers of [75] declares that the interaction of Ag NPs with virus cells directs to an escalation in actions of their programmed cell death i.e., apoptosis.

*DOI: http://dx.doi.org/10.5772/intechopen.99368*

**7. Anti-action operations of AgNPs**

**Figure 6.** *Elements subjected to nosocomial infections.*

*Silver Nanoparticles - Preparation Methods and Anti-Bacterial/Viral Remedy Impacts… DOI: http://dx.doi.org/10.5772/intechopen.99368*

for enhanced antimicrobial actions & zero thrombogenicity [67]. The writers also questioned the impact of Ag NPs on blood clotting, and the outcomes are fascinating. It should also be understood that the antimicrobial impact of Ag NPs coated titanium instruments is modified by UV light exposure [68].

Exploration in this branch had concluded an overall bacterial termination of Methicillin-resistant *staphylococcus aureus* (MRSA) as a result of Ag NPs synergic effect as a photocatalyst & visible light was accomplished [5, 69]. An identical energetic bactericidal effect was detected with stents & catheters used in cardiovascular operations [70]. So, it can be believed that the Ag NPs are advantageous ingredient to isolate differential ailments occurring in therapeutic organizations. Also, precautions should be taken to avoid their noxious impact on humans.

#### **7. Anti-action operations of AgNPs**

*Silver Micro-Nanoparticles - Properties, Synthesis, Characterization, and Applications*

**6. Nosocomial epidemic (hospital-acquired infections)**

the mediums.

puzzles for the science [61].

infections.

• The ablation demonstration for *"fs"* ablation in air was lessened than distilled water but *"ns"* pulses did not have any change of ablation energy in either of

• The self-absorption capability of Ag is higher at lower wavelengths [57, 60].

The predominating threats in the biomedical line are the penicillin-immunity of the living beings, product advancement behavior and its services in terms of hazardous, healing timespan & aftereffects on the mortal cells. Also, the revelation of infection-inducing non-bacterial microorganisms, supervising infection administration & avoiding nosocomial infections (**Figure 6**) are main confronting

A survey by WHO concluded that moderately 8.7% of world population has suffered from nosocomial disease, and approximately 1.4 million people suffered Hospital-Acquired Infections (HAI) [62]. Eastern Mediterranean & southeast Asian regions are HAI sensitive rather than the other regions. Nosocomial Infections covers categories likes surgical wounds, urinary & lower respiratory tract infections. The latter was particularly pronounced for the 2020 COVID-19

Avoidance of HAI demands a coordinated & overseen plan in which peculiar features must be calculated. The transmission of bacterial/viral microorganism from person to person is diminished by individual cleaning like handwashing, hand gloves, masks, working clothes, shoes, & sterilization of medical apparatus [63]. Also, higher the bacterial/viral protection, higher is the impact on wellbeing. Many theories have been executed worldwide for restricting HAI's. It is noted that Ag NPs utilization is highly emerging solution to quarantine the Nosocomial Infections,

The unmanaged & enormous use of penicillin and their bacterial hostility is a present-day menace for medicinal industry, which also consists of Ag NPs induced antibiotics [65]. Ag NPs obtained from bio-methods using *B. marisflavi* resulted high antibacterial actions against bacteria leading to nosocomial infections [66]. In therapeutic institutions, medical apparatus is the usual source of spreading infection. The quick fix to this problem could be the coating apparatus with Ag NPs to bypass bacterial contagion. Ag NPs are productively utilized in catheters

also, an efficient nano-weapon to multidrug resistance microorganisms [64].

**116**

**Figure 6.**

*Elements subjected to nosocomial infections.*

Many researchers have examined & published the antibacterial performances of Ag NPs. The bacterial cell membranes consist of sulfur (S) comprising proteins & involves amino acids. On inner & outer membrane Ag can blend in with them preventing bacterial expansion. Ag NPs also produce Ag ions which blends in with Deoxyribonucleic acid's (DNA's) phosphorus (P) and with *"S"* consisting of proteins, inhibiting the enzymes movement. Characteristics like "size" & "shape" of NPs guides to evaluate Ag NP's antimicrobial behavior. NPs of size <20 nm will execute a better attachment of *"S"* comprehending protein of membrane ending in cell death of bacteria as a result of maximum permeability via membrane [71].

**Figure 7** represents the interaction mechanism of Ag NPs surface-to-volume ratio on bacteria/virus. Nanomaterials has a nature, that smaller the NPs, greater surface interaction is exposed and contributes to better microbicidal effect [72, 73].

Shape of NPs also plays avital role to interact with the membrane walls. Analysis in [74] directs to large anti-activities towards *E. coli* bacteria with abbreviated triangles of Ag NPs better than those of spherical & rod-shaped NPs. It is also mentioned that Ag NPs <10 nm creates holes in the cell wall as a result of these holes the cytoplasmic is dispensed into the medium, responsible for controlling cell death without interaction between intracellular and extracellular proteins and bacterial nucleic acids. The writers of [75] declares that the interaction of Ag NPs with virus cells directs to an escalation in actions of their programmed cell death i.e., apoptosis.

**Figure 7.** *Demonstrating antibacterial features of silver nanoparticles.*

In simple words, Ag NPs are fascinating disinfectants better than merchandise like Acticoat™ & Silverline® for wound dressing & polyurethane ventricular catheter, respectively [70]. Moreover, Ag NPs are utilized in several merchandise-like surgical masks, toothpaste, hand wash, shampoo, detergent as well as humidifiers but their toxicity to human lives is still a top concern.

### **8. Early-stage treatment via respiration approaches with Ag NPs for COVID-19**

Numerous drug manufacturing experiences the well-known antimicrobial features of Ag NPs. The anti-bacterial/viral features of Ag are very well researched in the scientific world [76, 77].

To investigate and validate the anti-action features Ag NPs as a purification segment for medicinal benefits, and their functions for treatment & anticipation of viral disease for inhalers, was the prime intuition of this investigation. Viral & Bacterial ailments threats to respiratory supported patients in intensive care units (ICU) due to ventilator-associated pneumonia (VAP), are basic scenarios that are present day discussion topic. The nasopharynx and/or bronchial tree of the breathing organs (respiratory system) are vulnerable to be infected by any infections even by a regular bacteria/virus (**Figure 8**) [78, 79].

The sinking of the microorganism to the lower vent of the breathing organs aggravates the conditions, intensifying the immune response and consequence huge damage (**Figure 9**) [81, 82]. Therefore, a superior proficient approach to diminish the bacterial/viral growth at the very starting i.e., in the upper breathing organs. For example, patients with slight symptoms or patient's arrival at ICU in the therapeutic institution before any VAP infection.

#### **Figure 8.**

*Entry points of influenza into respiratory system. (A) The description of the human airways. Microbes first infects the upper vents and the rough cells in the bronchus and bronchioles. The adaptive resistance is initiated in lymph nodes along the airways. (B) The respiratory epithelia are especially equipped to defend from incoming pathogens by a layer of mucus (bronchus), ciliated cells (bronchus and bronchioles), and alveolar macrophages (alveoli).*

**119**

*\**

**Table 3.**

*Silver Nanoparticles - Preparation Methods and Anti-Bacterial/Viral Remedy Impacts…*

An adequate solution for upper & lower respiratory system remedy is briefed

• Colloidal Ag are nanosized Ag pieces ranging from 1 to 100 nm diameter [80].

Minimum Inhibitory Concentration (MIC) should be developed to calculate the authorize dosage of any effective agent. The delicacy of MIC (μg/ml) to NP size, is

NPs >10 nm are ultimately resulting than those >25 nm [83, 84]. Higher density was noticed with the small sizes of NPs which leads extraordinary synergy with microorganisms. That is why, the MIC of NPs > 10 nm must be tiny than that of large sized NPs and is experimentally absolute (see **Table 4**) [80]. With every publication the value to MIC has varied with the NP size. It has been stated in the research of the effect of Ag NPs size on anti-viral efficacy in HIV treatment. These results are concluded by

assuming that because the virus size is ≥ 100 nm for e.g., HIV has a size of 120 nm. And to interact and act on the virus the AG NPs must be tiny for the virus particle (approx.

of 10 nm). These assumptions were made by direct imaging of NPs [85].

**Element IC50\*** Silver Nanoparticles 0.44 mg/mL (± 0.3) Silver sulfadiazine (ions) 39.33 μg/mL (± 14.60)

There is a debate on colloidal particles being more persuasive than ionic Ag for anti-viral features [83], as described in **Table 3** for Human Immunodeficiency Viruses (HIV). Evaluation the anti-action of colloidal Ag will help understand the

in the paper. It is mandatory that for intake, the difference between ionic Ag solution & colloidal Ag and Ag particles suspensions/solution in water has the

• In ionic Ag, the atomic Ag ions are soluble in water.

problematic to settle conclusions from disclosed studies.

quantity of Ag NPs for healthy inhalation.

*The half maximal inhibitory concentration.*

*Anti-action impacts of Ag ion & Ag NPs against HIV-1 [83].*

*DOI: http://dx.doi.org/10.5772/intechopen.99368*

relevant structure.

*Microbes of HAI - VAP [80].*

**Figure 9.**

*Silver Nanoparticles - Preparation Methods and Anti-Bacterial/Viral Remedy Impacts… DOI: http://dx.doi.org/10.5772/intechopen.99368*

**Figure 9.** *Microbes of HAI - VAP [80].*

*Silver Micro-Nanoparticles - Properties, Synthesis, Characterization, and Applications*

but their toxicity to human lives is still a top concern.

by a regular bacteria/virus (**Figure 8**) [78, 79].

therapeutic institution before any VAP infection.

**COVID-19**

in the scientific world [76, 77].

In simple words, Ag NPs are fascinating disinfectants better than merchandise like Acticoat™ & Silverline® for wound dressing & polyurethane ventricular catheter, respectively [70]. Moreover, Ag NPs are utilized in several merchandise-like surgical masks, toothpaste, hand wash, shampoo, detergent as well as humidifiers

**8. Early-stage treatment via respiration approaches with Ag NPs for** 

Numerous drug manufacturing experiences the well-known antimicrobial features of Ag NPs. The anti-bacterial/viral features of Ag are very well researched

To investigate and validate the anti-action features Ag NPs as a purification segment for medicinal benefits, and their functions for treatment & anticipation of viral disease for inhalers, was the prime intuition of this investigation. Viral & Bacterial ailments threats to respiratory supported patients in intensive care units (ICU) due to ventilator-associated pneumonia (VAP), are basic scenarios that are present day discussion topic. The nasopharynx and/or bronchial tree of the breathing organs (respiratory system) are vulnerable to be infected by any infections even

The sinking of the microorganism to the lower vent of the breathing organs aggravates the conditions, intensifying the immune response and consequence huge damage (**Figure 9**) [81, 82]. Therefore, a superior proficient approach to diminish the bacterial/viral growth at the very starting i.e., in the upper breathing organs. For example, patients with slight symptoms or patient's arrival at ICU in the

*Entry points of influenza into respiratory system. (A) The description of the human airways. Microbes first infects the upper vents and the rough cells in the bronchus and bronchioles. The adaptive resistance is initiated in lymph nodes along the airways. (B) The respiratory epithelia are especially equipped to defend from incoming pathogens by a layer of mucus (bronchus), ciliated cells (bronchus and bronchioles), and alveolar* 

**118**

**Figure 8.**

*macrophages (alveoli).*

An adequate solution for upper & lower respiratory system remedy is briefed in the paper. It is mandatory that for intake, the difference between ionic Ag solution & colloidal Ag and Ag particles suspensions/solution in water has the relevant structure.


There is a debate on colloidal particles being more persuasive than ionic Ag for anti-viral features [83], as described in **Table 3** for Human Immunodeficiency Viruses (HIV). Evaluation the anti-action of colloidal Ag will help understand the quantity of Ag NPs for healthy inhalation.

Minimum Inhibitory Concentration (MIC) should be developed to calculate the authorize dosage of any effective agent. The delicacy of MIC (μg/ml) to NP size, is problematic to settle conclusions from disclosed studies.

NPs >10 nm are ultimately resulting than those >25 nm [83, 84]. Higher density was noticed with the small sizes of NPs which leads extraordinary synergy with microorganisms. That is why, the MIC of NPs > 10 nm must be tiny than that of large sized NPs and is experimentally absolute (see **Table 4**) [80]. With every publication the value to MIC has varied with the NP size. It has been stated in the research of the effect of Ag NPs size on anti-viral efficacy in HIV treatment. These results are concluded by assuming that because the virus size is ≥ 100 nm for e.g., HIV has a size of 120 nm. And to interact and act on the virus the AG NPs must be tiny for the virus particle (approx. of 10 nm). These assumptions were made by direct imaging of NPs [85].


#### **Table 3.**

*Anti-action impacts of Ag ion & Ag NPs against HIV-1 [83].*

#### *Silver Micro-Nanoparticles - Properties, Synthesis, Characterization, and Applications*


**Table 4.**

*MIC of colloidal Ag for antibacterial effects [80].*

#### **Figure 10.**

*a) HIV-1 virus commuting silver; b) HIV-1 viruses without commuting silver; c) complex size distribution of Ag NPs commuted with HIV-1 virus, resulted via tested preparations [85].*

Fascinating fact is that the culminating virus attachment for NP impact ranged between 3 and 7 nm (see **Figure 10**) [85]. Hence, the size-dependency for NP interaction to virus is stated.

In this chapter we have discussed miniscule measure of Ag NPs utilization in the biomedical work, whereas worldwide testing rooms are actively researching on it. In overall it could be said that, presently, the anti-bacterial/viral features of colloidal Ag are definite but in case of respiratory disease, a lot of must be researched deeply. Also, the MIC size of colloidal Ag ranging between 10 μg / ml and 25 μg/ml (indirect conclusions, requires deep study to specify) & 3–7 nm, respectively, have impressive suppression on viral infections.

Expecting, these formulations can be persuasively precautionary & remedy in beginning of respiratory viral ailments, including COVID-19/SARS-CoV-21. Such remedy could be helpful for bacterial ailments like prevention of clinical VAP & in ICU's and only half dosages compared to other anti-bacterial.

**121**

of contagious ailments.

*Silver Nanoparticles - Preparation Methods and Anti-Bacterial/Viral Remedy Impacts…*

catastrophic consequences are known only through animal & In vitro tests.

exposure, concentrated microwave exposure, and other.

*"ns"* pulsed laser generates strong heat.

reagents and stabilizing surfactants used.

observations & particular objective investigation.

Until now, high assumptions are made from Ag NPs applications, but their over concentration can be threatening to human lives [86]. For example, excessive concentration can cause high blood pressure [87]. However, the hazardous of AG NPs is not that higher because of their nano size and possibly end in the

The adequate & conservative utilization of Ag NPs should be concrete, as their

Because Ag NPs have chemical stability and retains uncommon features, they are used in fields like therapeutic, environment, food industry, biotechnology, microelectronics, and many other. Moreover, there antimicrobial assistance has compelling vigilant ramifications against microbes. Ag NPs are an elemental ingredient to configuration of products with antimicrobial actions due to their non-toxicity to mortal bodies but only in low mixtures. These uncommon features of Ag NPs have interested many researchers for innovating modern techniques to obtain their different size & shapes. Many leading research teams are enhancing the Ag NPs manufacturing methods using chemical reduction, laser ablation, electron beam

The PLAL (branch of Physical methods) tends to occur any exceptional environmental side-effects by producing pure & clean metal NPs with uncommon characteristics, without any organic/inorganic chemical agents. Laser wavelength (λ) & intensity are vital parameters required for NP construction. For example, green lasers can construct NPs with better efficiency than infrared (IR) lasers and

The hasty incorporation & flexibility of chemical methods into distinctive surroundings is the motivation for scientists to keep up with the mechanistic conditions of the anti-microbial/viral/inflammatory impacts of Ag NPs. This takes place with the alteration in the form, NP size by altering the reaction requirements,

Whereas biological methods for NP synthesis possess vast alternatives for using natural & artificial stabilizing surfactants. Use of bio-organisms for NP extraction might commit to the surrounding purification. Surface chemistry & morphology, size, shape, coating agent, NP agglomeration & dissolution rate, particle reactivity in solution, and ion release efficiency, are the dependencies for biological actions of Ag NP. The fascinating use of Ag NPs in medicinal purposes especially against contagious ailments as a result of their extraordinary microbicidal spectrum. In recent years, studies have confirmed Ag NPs impact on viruses, which was expected to be opposing. Contact infection between Health Care Workers and patients could be prevented effectively with Ag NPs, must be advised. Optimistic results have been obtained for Ag NPs contribution in enhancing the microbicidal effects of biocompatible medical devices. Expectations have aroused for contribution of effectual utilization of Ag NPs in modification of medical science for treatment

With the time the research in this line has reached to a far point but there is a lot more to be researched like to improve & interpret the last-longing benefits of NPs on mortal souls. Also, the optimal accumulation on the distinct points of the ailments in sufferer without noxious impact on living beings. It requires all hands joined from around the globe to put their efforts for research in enhancing technologies for generating NPs with various features, as well as carrying out therapeutic

*DOI: http://dx.doi.org/10.5772/intechopen.99368*

urine [88].

**9. Ending**

*Silver Nanoparticles - Preparation Methods and Anti-Bacterial/Viral Remedy Impacts… DOI: http://dx.doi.org/10.5772/intechopen.99368*

Until now, high assumptions are made from Ag NPs applications, but their over concentration can be threatening to human lives [86]. For example, excessive concentration can cause high blood pressure [87]. However, the hazardous of AG NPs is not that higher because of their nano size and possibly end in the urine [88].

The adequate & conservative utilization of Ag NPs should be concrete, as their catastrophic consequences are known only through animal & In vitro tests.

### **9. Ending**

*Silver Micro-Nanoparticles - Properties, Synthesis, Characterization, and Applications*

7 nm Ag NPs 6.25 7.5 29 nm Ag NPs 13.02 16.67 89 nm Ag NPs 11.79 33.71

Fascinating fact is that the culminating virus attachment for NP impact ranged

*a) HIV-1 virus commuting silver; b) HIV-1 viruses without commuting silver; c) complex size distribution of* 

In this chapter we have discussed miniscule measure of Ag NPs utilization in the biomedical work, whereas worldwide testing rooms are actively researching on it. In overall it could be said that, presently, the anti-bacterial/viral features of colloidal Ag are definite but in case of respiratory disease, a lot of must be researched deeply. Also, the MIC size of colloidal Ag ranging between 10 μg / ml and 25 μg/ml (indirect conclusions, requires deep study to specify) & 3–7 nm, respectively, have

Expecting, these formulations can be persuasively precautionary & remedy in beginning of respiratory viral ailments, including COVID-19/SARS-CoV-21. Such remedy could be helpful for bacterial ailments like prevention of clinical VAP & in

between 3 and 7 nm (see **Figure 10**) [85]. Hence, the size-dependency for NP

*Bacteria E. coli S. aureus*

**Specimen MIC (**μ**g/mL)**

**120**

**Figure 10.**

interaction to virus is stated.

impressive suppression on viral infections.

ICU's and only half dosages compared to other anti-bacterial.

*Ag NPs commuted with HIV-1 virus, resulted via tested preparations [85].*

**Table 4.**

*MIC of colloidal Ag for antibacterial effects [80].*

Because Ag NPs have chemical stability and retains uncommon features, they are used in fields like therapeutic, environment, food industry, biotechnology, microelectronics, and many other. Moreover, there antimicrobial assistance has compelling vigilant ramifications against microbes. Ag NPs are an elemental ingredient to configuration of products with antimicrobial actions due to their non-toxicity to mortal bodies but only in low mixtures. These uncommon features of Ag NPs have interested many researchers for innovating modern techniques to obtain their different size & shapes. Many leading research teams are enhancing the Ag NPs manufacturing methods using chemical reduction, laser ablation, electron beam exposure, concentrated microwave exposure, and other.

The PLAL (branch of Physical methods) tends to occur any exceptional environmental side-effects by producing pure & clean metal NPs with uncommon characteristics, without any organic/inorganic chemical agents. Laser wavelength (λ) & intensity are vital parameters required for NP construction. For example, green lasers can construct NPs with better efficiency than infrared (IR) lasers and *"ns"* pulsed laser generates strong heat.

The hasty incorporation & flexibility of chemical methods into distinctive surroundings is the motivation for scientists to keep up with the mechanistic conditions of the anti-microbial/viral/inflammatory impacts of Ag NPs. This takes place with the alteration in the form, NP size by altering the reaction requirements, reagents and stabilizing surfactants used.

Whereas biological methods for NP synthesis possess vast alternatives for using natural & artificial stabilizing surfactants. Use of bio-organisms for NP extraction might commit to the surrounding purification. Surface chemistry & morphology, size, shape, coating agent, NP agglomeration & dissolution rate, particle reactivity in solution, and ion release efficiency, are the dependencies for biological actions of Ag NP.

The fascinating use of Ag NPs in medicinal purposes especially against contagious ailments as a result of their extraordinary microbicidal spectrum. In recent years, studies have confirmed Ag NPs impact on viruses, which was expected to be opposing. Contact infection between Health Care Workers and patients could be prevented effectively with Ag NPs, must be advised. Optimistic results have been obtained for Ag NPs contribution in enhancing the microbicidal effects of biocompatible medical devices. Expectations have aroused for contribution of effectual utilization of Ag NPs in modification of medical science for treatment of contagious ailments.

With the time the research in this line has reached to a far point but there is a lot more to be researched like to improve & interpret the last-longing benefits of NPs on mortal souls. Also, the optimal accumulation on the distinct points of the ailments in sufferer without noxious impact on living beings. It requires all hands joined from around the globe to put their efforts for research in enhancing technologies for generating NPs with various features, as well as carrying out therapeutic observations & particular objective investigation.

*Silver Micro-Nanoparticles - Properties, Synthesis, Characterization, and Applications*
