**2. Antimicrobial applications of nanoparticles**

The rapid emergence of resistant pathogens is occurring worldwide, endangering the efficacy of antibiotics, which have pushed medicine to evolve and save millions of lives. Resistance of the pathogens has been attributed to the overuse and misuse of antibiotic medications, as well as the lack of new strategies for antibacterial development to address the challenge [11, 12]. This challenge suggests that the focus of research on resistance pathogens must be turned to the discovery of novel strategies to fight the pathogen infections. One of the new areas that is emerging in

**15**

resistance [22, 23].

*In vitro Antimicrobial Activity Evaluation of Metal Oxide Nanoparticles*

response for this challenging menace is the use of nanotechnology, mainly by the identification of how the manipulation of materials for the synthesis of NPs could

Research on the synthesis, characterization and application of NPs as an antimicrobial system is a new area of interest in the biomedical and healthcare fields due to the possible enhancement of nanoparticles within their physiochemical behavior against drug-resistant pathogens due to size effect, doping effect, could be costeffective and they are quite stable enough for long-term storage with a prolonged shelf-life. Moreover, the NPs could be subjected to sterilization by methods of high temperature, gamma irradiation or plasma treatment without losing its properties

In reference to the biomedical field, the benefits of nanotechnology have been quite substantial, for example, there are devices with antimicrobial nanoproperties such as heart valves, catheters, and dental implants [10]. The type of nanolayers covering these kind of devices can delay or inhibits the adhesion and growth of bacteria such as *Streptococcus mutans*, *Staphylococcus epidermis*, and *Escherichia coli*. Other implantable material is bone cement based polymethyl methacrylate (PMMA) with Ag nanoparticles that have demonstrated significant reduction in the number of arthroplasty surgery-related infections, including methicillin-resistant *Staphylococcus aureus* (MRSA), *S. aureus*, *S. epidermidis*, and *Acinetobacter baumannii*

The application of nanoparticles used to fight against pathogens consist mainly

Besides as metal nanoparticles could target the bacterial cell wall; there is an opportunity to dope the nanoparticles with relevant antibiotics to enhance their antibacterial action through synergy offering multiple advantages as controllable with sustained and relatively uniform distribution release in the target tissue, improving the solubil-

The resistance of microorganisms to the action of antimicrobial agents, especially antibiotics, is a serious public health problem, which has been a reason for the

The manipulation on a nanoscale of metal oxide has provided new research in the pharmaceutical area due to the antimicrobial properties of these oxides, according to data revealed in *in vitro* studies [20, 21]. In this sense, the metal oxide NPs between 1 and 100 nm with different shapes allow their physical and chemical properties could become in some promise antimicrobial agents against infectious diseases for the recent findings about their interaction which has become of vital importance due to the increasing of infection diseases by bacterial

of metals and metal oxides of zinc, silver, copper or titanium, because they naturally exhibit microbiocidal or microbiostatic actions and have demonstrated bactericidal activity against both Gram-positive and Gram-negative bacteria. The bactericidal application of metal NPs is based on the mechanism that affect the respiration system by photocatalytic production of reactive oxygen species (ROS) that damage cellular and viral components that ultimately leads to bacterial death, compromising the bacterial cell wall/membrane, inhibition of enzyme activity and DNA synthesis, interruption of energy transduction and the most important the

ity, minimized side effects and enhanced cellular internalization [14, 18, 19].

search and development of new antimicrobials through nanotechnology.

pathogens do not develop resistance to metal NPs [16, 17].

**3. Metal oxide nanoparticles as antimicrobial agents**

be utilized for the therapeutic management of pathogen infections [13].

*DOI: http://dx.doi.org/10.5772/intechopen.84369*

or inactivation [14].

infections [10, 15].

#### *In vitro Antimicrobial Activity Evaluation of Metal Oxide Nanoparticles DOI: http://dx.doi.org/10.5772/intechopen.84369*

*Nanoemulsions - Properties, Fabrications and Applications*

potential therapy application.

being [7–9].

industry.

influence their antimicrobial response.

ate antimicrobial agents and materials.

**2. Antimicrobial applications of nanoparticles**

In the science of materials, there is an interest in the development of new antimicrobial therapies, capable of fighting opportunistic infections. For this reason, it is important as a first step, to take into account the different laboratory methods that can be used to evaluate antimicrobial activity *in vitro*. The aim of this methods is to detect possible drug resistance in common pathogens [2], but also which are the most appropriate assays to be used in new agents and materials what that have a

Nanotechnology and tissue engineering are potential applications for the reported antimicrobial properties of nanoparticles (NPs). Some of the potential advantages of NPs, to fight against microorganisms, are that they do not generate resistance and are a safe potential antimicrobial alternative for clinical use [3–5]. However, the research in this area is needed to understand the mechanism of action of NPs and how to design better therapies. In recent years, nanoparticles have been incorporated into the medical field as an alternative to new antimicrobial agents, especially oxides based in silver (Ag), copper (Cu), and titanium (Ti) [6]. On the other hand, findings have raised concerns about their possible toxic effects in humans, triggering an interest to investigate more about the nanotoxicology and the search for new antibacterial nanomaterials with nontoxic properties for human

The antibacterial activity of the NPs depends of the size and shape; so it requires active research of nanometer-scale materials. Recently, basic and applied research has been done on various metal oxides with different shapes and sizes has carried out for their application in a broad scale of areas such as catalysis, in semiconduc-

The physical and chemical properties of metal oxide NPs allow their interaction with biological systems, which has become of vital importance due to the increasing resistance of bacteria. Within these properties, there are shape, size, roughness, zeta potential and coatings, among others [5, 10]. The antimicrobial activity presented by the NPs of metal oxides could have a mainly therapeutic application, but it can also be extended to the food industry, to water purification and to the textile

The present chapter will be focused on recent reports that explore the relationships between the use of NPs in the medical field, with an emphasis on their role as antimicrobial agents and the physicochemical properties of metal oxide NPs that

Additionally, findings will address antimicrobial activity of novel metal oxides NPs based in zinc, manganese, iron and magnesium. Also, we will discuss diverse methods for the assessment of antimicrobial activity that can have uses for metal oxide NPs and which complies with quality according to official standards to evalu-

The rapid emergence of resistant pathogens is occurring worldwide, endangering the efficacy of antibiotics, which have pushed medicine to evolve and save millions of lives. Resistance of the pathogens has been attributed to the overuse and misuse of antibiotic medications, as well as the lack of new strategies for antibacterial development to address the challenge [11, 12]. This challenge suggests that the focus of research on resistance pathogens must be turned to the discovery of novel strategies to fight the pathogen infections. One of the new areas that is emerging in

tors, sensors, controlled release of drugs and as antimicrobial agents.

**14**

response for this challenging menace is the use of nanotechnology, mainly by the identification of how the manipulation of materials for the synthesis of NPs could be utilized for the therapeutic management of pathogen infections [13].

Research on the synthesis, characterization and application of NPs as an antimicrobial system is a new area of interest in the biomedical and healthcare fields due to the possible enhancement of nanoparticles within their physiochemical behavior against drug-resistant pathogens due to size effect, doping effect, could be costeffective and they are quite stable enough for long-term storage with a prolonged shelf-life. Moreover, the NPs could be subjected to sterilization by methods of high temperature, gamma irradiation or plasma treatment without losing its properties or inactivation [14].

In reference to the biomedical field, the benefits of nanotechnology have been quite substantial, for example, there are devices with antimicrobial nanoproperties such as heart valves, catheters, and dental implants [10]. The type of nanolayers covering these kind of devices can delay or inhibits the adhesion and growth of bacteria such as *Streptococcus mutans*, *Staphylococcus epidermis*, and *Escherichia coli*. Other implantable material is bone cement based polymethyl methacrylate (PMMA) with Ag nanoparticles that have demonstrated significant reduction in the number of arthroplasty surgery-related infections, including methicillin-resistant *Staphylococcus aureus* (MRSA), *S. aureus*, *S. epidermidis*, and *Acinetobacter baumannii* infections [10, 15].

The application of nanoparticles used to fight against pathogens consist mainly of metals and metal oxides of zinc, silver, copper or titanium, because they naturally exhibit microbiocidal or microbiostatic actions and have demonstrated bactericidal activity against both Gram-positive and Gram-negative bacteria. The bactericidal application of metal NPs is based on the mechanism that affect the respiration system by photocatalytic production of reactive oxygen species (ROS) that damage cellular and viral components that ultimately leads to bacterial death, compromising the bacterial cell wall/membrane, inhibition of enzyme activity and DNA synthesis, interruption of energy transduction and the most important the pathogens do not develop resistance to metal NPs [16, 17].

Besides as metal nanoparticles could target the bacterial cell wall; there is an opportunity to dope the nanoparticles with relevant antibiotics to enhance their antibacterial action through synergy offering multiple advantages as controllable with sustained and relatively uniform distribution release in the target tissue, improving the solubility, minimized side effects and enhanced cellular internalization [14, 18, 19].
