**1. Introduction**

[64] Cardo LJ. Leishmania: risk to the blood supply. *Transfusion* 2006,46(9),1641.

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cord blood stem cell products. *Transfusion* 2008, 48, 2629.

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[65] Wainwright M. Pathogen inactivation in blood products. *Curr Med Chem* 2002, 9, 127. [66] Goodrich RP, Platz MS, Martin CB. Use of visible light to reduce of wavelengths of 500 to 550 nm to reduce the number of pathogen in the blood and blood components.

[67] Ruane PH, Edrich R, Gampp D, Keil SD, Leonard RL, Goodrich RP. Photochemical inactivation of selected viruses and bacteria in platelet concentrates using riboflavin

[68] Trannoy LL, van Hensbergen Y, Lagerberg JWM, Brand A. Photodynamic treatment with mono-phenyl-tri-(N-methyl-4-pyridyl)-porphyrin for pathogen inactivation in

[69] Dutta S, Ray D, Kolli BK, Chang K-P. Photodynamic sensitization of Leishmania am‐ azonensis in both extracellular and intracellular stages with aluminum phthalocya‐ nine chloride for photolysis in vitro. *Antimicrob Agents Chemother* 2005, 49(11), 4474.

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Nanoscience and Nanothecnology are revolutionizing the world of science and technology, bringing high expectations for technological innovation and the development of areas, such as: aerospace, agribusiness, defense, energy, environment, nanodevices, nanosensors, textiles, biotechnology and health. As part of its application to the health sciences, one of the priority targets are negligible diseases such as Leishmaniasis. In this context, the main objective of this chapter is to show the potential of some classes of ceramic nanoparticles and magnetic and ferroelectric nanocomposites based on natural rubber to modulate the growth of parasite colony of *Leishmania braziliensis* (LB) and to evaluate the toxicity of these materials against mammal cells.

#### **1.1. Nanoscience and nanotechnology applied to neglected diseases**

Materials with sizes ranging between 1x10-9 m and 100x10-9 m are called nanomaterials regard‐ less of their nature, whether ceramic, polymer, metal or composite. When a material has dimensions on the nanometric scale, its surface properties and volume are differentiated in relationtomaterialproperties at ahigherdimensional scale.Thesedifferencesoccurbecause the surface/volume ratio orhighaspectratios arenotlinearfordifferentdimensional scales andthis is in part responsible for the differentiated properties presented by nonascale materials. These

© 2014 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

differentiated properties can be transferred to other materials by the insertion of the nanomate‐ rials in a matrix of a different nature and nanometric scale not generating a nanocomposite material[1, 2]. In general, the choice of polymer as a matrix or continuous phase is preferable since most have appreciable thermal and mechanical properties. Other properties must also be takenintoaccount, suchashydrophobic/hydrophilicbalance,chemical stabilityandbiocompat‐ ibility. The nanometric component, generally inorganic, known as the dispersed phase, can provide a higher mechanical, thermal stability and also biological properties [3].

Multidisciplinary researches involving nanoscience, nanotechnology, materials science and engineering, biotechnology and health sciences have gained great strength in recent decades, aiming to increase the number of tools for addressing problems [4]. Each day new materials and methodologies are tested in fighting diseases such as cancer and diseases neglected by the pharmaceutical industry, for example, malaria, leishmaniasis and Chagas' disease. As a result of this innovation, nanocomposites and composites based in natural rubber filled with ceramic particle and nanoparticles can be used in biological applications, aiming at development of devices such as intelligent bandages or agents of control and reduction of parasitic colonies [5].

#### **1.2.** *Leishmania braziliensis*

Leishmaniasis is a endemic and parasitic infection caused by the Leishmania genus protozoa. Approximately 1.5 million people were affected by cutaneous leishmaniasis, which reaches 88 countries and has compulsory notification in only 30 of them. Presents itself throughout the Americas and Brazil is the country that has the highest prevalence of cases. Leishmaniasis is a typically tropical disease from Trypanosomatidae family, affecting the skin (cutaneous leishmaniasis, caused by *Leishmania braziliensis* protozoans) or viscera (visceral leishmaniasis, caused by *Leishmania donovani* protozoans), transmitted by the bite of the vector, a phleboto‐ mine sand fly popularly known as "straw mosquito", which utilizes both animals and humans as host [6, 7].

Protozoans of Leishmania genus are unicellular, eukaryotic, heterotrophic, with asexual reproduction by binary fission, and feed via uptake of non-self-generated food. Within the human body, Leishmania protozoans feed of proteins present intracellularly or in blood plasma, and reproduce only within macrophages or similar cells of the immune system[6, 7].

#### **1.3. Ceramic materials**

Ceramic materials (in general, oxides, carbides or nitrides) are inorganic, non-metallic substances consisting of metallic and non-metallic elements connected together by covalent and/or ionic bonds. This class of materials displays a set of distinguished physical and chemical properties such as high mechanical strength, high hardness, low tenacity, low thermal and electrical conductivity, high melting point, among others. As a result of the variety of proper‐ ties that ceramic materials exhibit, these materials has various industrial applications as, for example, bricks, crockery, refractory glass mortars, magnetic materials, electronic devices, fibers, abrasives and aerospace components.

Ceramic phases preparation processes can be classified primarily in chemical and physical routes, and the appropriate processing route selection depends on several aspects associated with the desired final product characteristics, such as desired dimensional scale, final product purity degree, ceramic phase complexity, amount of obtained material, desired physical and chemical properties and cost of the final product. Among several ceramic phases currently known, investigated and used, those with magnetic and ceramic properties with ferroelectric properties can be highlighted, e.g. ferrite with inverse spinel type structure and niobate potassium strontium with tetragonal tungsten bronze structure [8, 9].

#### *1.3.1. Inverse spinel structure and the nickel-zinc ferrite*

differentiated properties can be transferred to other materials by the insertion of the nanomate‐ rials in a matrix of a different nature and nanometric scale not generating a nanocomposite material[1, 2]. In general, the choice of polymer as a matrix or continuous phase is preferable since most have appreciable thermal and mechanical properties. Other properties must also be takenintoaccount, suchashydrophobic/hydrophilicbalance,chemical stabilityandbiocompat‐ ibility. The nanometric component, generally inorganic, known as the dispersed phase, can

Multidisciplinary researches involving nanoscience, nanotechnology, materials science and engineering, biotechnology and health sciences have gained great strength in recent decades, aiming to increase the number of tools for addressing problems [4]. Each day new materials and methodologies are tested in fighting diseases such as cancer and diseases neglected by the pharmaceutical industry, for example, malaria, leishmaniasis and Chagas' disease. As a result of this innovation, nanocomposites and composites based in natural rubber filled with ceramic particle and nanoparticles can be used in biological applications, aiming at development of devices such as intelligent bandages or agents of control and reduction of parasitic colonies [5].

Leishmaniasis is a endemic and parasitic infection caused by the Leishmania genus protozoa. Approximately 1.5 million people were affected by cutaneous leishmaniasis, which reaches 88 countries and has compulsory notification in only 30 of them. Presents itself throughout the Americas and Brazil is the country that has the highest prevalence of cases. Leishmaniasis is a typically tropical disease from Trypanosomatidae family, affecting the skin (cutaneous leishmaniasis, caused by *Leishmania braziliensis* protozoans) or viscera (visceral leishmaniasis, caused by *Leishmania donovani* protozoans), transmitted by the bite of the vector, a phleboto‐ mine sand fly popularly known as "straw mosquito", which utilizes both animals and humans

Protozoans of Leishmania genus are unicellular, eukaryotic, heterotrophic, with asexual reproduction by binary fission, and feed via uptake of non-self-generated food. Within the human body, Leishmania protozoans feed of proteins present intracellularly or in blood plasma, and reproduce only within macrophages or similar cells of the immune system[6, 7].

Ceramic materials (in general, oxides, carbides or nitrides) are inorganic, non-metallic substances consisting of metallic and non-metallic elements connected together by covalent and/or ionic bonds. This class of materials displays a set of distinguished physical and chemical properties such as high mechanical strength, high hardness, low tenacity, low thermal and electrical conductivity, high melting point, among others. As a result of the variety of proper‐ ties that ceramic materials exhibit, these materials has various industrial applications as, for example, bricks, crockery, refractory glass mortars, magnetic materials, electronic devices,

provide a higher mechanical, thermal stability and also biological properties [3].

**1.2.** *Leishmania braziliensis*

414 Leishmaniasis - Trends in Epidemiology, Diagnosis and Treatment

as host [6, 7].

**1.3. Ceramic materials**

fibers, abrasives and aerospace components.

Among the materials with inverse spinel type structure, is highlighted the Ni-Zn ferrite paramagnetic or superparamagnetic ceramic phase, with cubic symmetry and space group Fd3m unit cell displaying an occupation represented by (*Znx* 2+ *Fe*1−*<sup>x</sup>* 3+ ) *N i x* 2+ *F e*1+*<sup>x</sup>* 3+ *<sup>O</sup>*<sup>4</sup> <sup>2</sup><sup>−</sup> [10, 11]. In this formula the transition metal ions inside the parentheses occupy the tetrahedral site D, while the metal ions inside the brackets occupy the octahedral site E.

Considering the absence of Zn2+ cations in the ferrite, the amount of iron in both atomic sites would be equal and their contribution to the magnetic dipole moment would be canceled, and the formation of the material magnetic dipole moment would be responsibility for Ni2+ cations. Doping the ferrite with Zn2+ cations, there is a migration of Fe3+ cations from tetrahedral sites to octahedral sites, unbalancing initial equality of Fe3+ cations. Therefore there is an abrupt increase in magnitude of the magnetic dipole moment, because Fe3+ and Zn2+ cations are contributing to the dipole moment of the material. Thus, it is possible to produce a large number of intrinsically magnetic ferrite by appropriate substitution of metallic ions. Figure 1 presents a representation of a portion of nickel-zinc ferrite with Ni0.5Zn0.5Fe2O4 stoichiometry and structure type inverse spinel, with octahedral sites FeO6 or NiO6 in blue and tetrahedral sites FeO4 or ZnO4 in red.

**Figure 1.** Oxide nickel-zinc ferrite representation, with stoichiometry Ni0.5Zn0.5Fe2O4 with structure type inverse spinel. Octahedral sites FeO6 or NiO6 are presented in blue and tetrahedral sites FeO4 or ZnO4 are presented in red.

Regarding magnetic ceramics, Ni-Zn ferrites stand out and attract scientific community interest, due to its high electrical resistivity, differentiated magnetic properties and several technological applications in electronics, telecommunications and biotechnology [8]. They are generally used in cores of transformers and inductors for high-frequency microwave devices, telecommunication systems and radars, high-speed read and recording magnetic heads, cellular telephony, hospital equipments, among others. In microwave-absorption devices (e.g. electromagnetic interference shielding), absorption capacity may be generated/potentiated by altering material magnetic or dielectric properties [12].

#### *1.3.2. TTB structure and potassium-strontium niobate*

Tetragonal tungsten bronze (TTB) crystalline structure is considered a structure derived from classic perovskite, where the central octahedral structure BO6 is converted into three different types of cavities, tetrahedral and pentagonal tunnels similar to those found in perovskite structure which are favorable for substitution by cations, and trigonal tunnels are favorable for substitution by smaller cations and anions [9].

TTB structure can be described by chemical formula A'2B'4C'4Nb10O30, where A', B' and C' represent different sites on the structure [13]. Depending on the number of sites available, TTB niobates are natural candidates to host structures, due to the possibility of a wide variety of cation substitutions, similar to what occurs with lead zirconate titanate (PbZnTiO3). B' cavity has a cube-octahedral coordination of oxygen atoms; A' cavities have pentagonal prismatic coordinations, while C' cavities have trigonal prismatic coordinations. The size of these cavities decreases following the order A' > B' > C'. In TTB-type compounds, alkali and alkaline earth metals are located at A' and B' sites, while only cations with small atomic radius such as Li are located in C' site. TTB-type compounds with formula A6Nb10O30, A'= Sr or Ba exhibit semicon‐ ductor characteristics which can be incremented when dopants are added.

Niobates with TTB-type structure such as KSr2Nb5O15, NaSr2Nb5O15, KBa2Nb5O15, Na‐ Ba2Nb5O15 and K3Li2Nb5O15 have created interest mainly by high anisotropy of the crystal structure. Among TTB-structure oxides, strontium potassium niobate oxide (KSr2Nb5O15) stands out for being a classic ferroelectric material with Curie temperature close to 430 K[14], belonging to a class of ceramic composites which have great potential application as sensing devices, actuators, memories, transducers, filters and capacitors.

Figure 2 shows a representation of strontium potassium niobate oxide structure, with oxygen and niobium octahedra in blue and yellow dark, pentagonal sites with potassium atoms (K1+), tetrahedral sites with strontium atoms (Sr2+) and vacant trigonal sites. This type of structure has two niobium types, which differ from each other by crystallographic position, multiplicity and occupancy factor. Nb(I) leads to NbO6 sites identified by their blue color, and Nb(II) leads to NbO6 sites identified by dark yellow color. The ratio between Nb atoms is 4 Nb(I) to 1 Nb (II).

#### **1.4. Natural rubber**

Latex is extracted from rubber tree stem, more specifically, from lactiferous vessels located in the cortex, and is responsible for bringing food to the tree top. From a chemical point of view, Utilization of Composites and Nanocomposites Based on Natural Rubber and Ceramic Nanoparticles as Control... http://dx.doi.org/10.5772/57211 417

**Figure 2.** Representation of strontium potassium niobate oxide (KSr2Nb5O15) with tetragonal tungsten bronze struc‐ ture. Pentagonal sites occupied by atoms of potassium (K1+), tetragonal sites occupied by atoms of strontium (Sr2+) and trigonal vacant sites are highlighted.

latex is a stable colloidal dispersion of a polymer in an aqueous medium. The dispersed polymer is aggregated in the form of particles with approximately spherical geometry (natural rubber micelles), with typical diameters between 30 and 1, 000 nm [15].

The latex used in this work was collected from rubber trees of *Hevea brasiliensis* species, clone RRIM 600. This is a secondary clone developed by the Rubber Research Institute of Malaysia - RRIM, the most planted in the plateau region of São Paulo Brazilian state, due to its good performance and effect on production. This clone presents tall trees with vertical stem and fast growing when young. Its high production is highlighted, being one of the clones that has a higher dry rubber productivity.

Latex composition is, on average, 35% natural rubber (hydrocarbons), which compound is 2 methyl-1, 3-butadiene (C5H8), commercially known as isoprene. Recently-extracted latex is a neutral substance at room temperature with a pH between 6.0 and 7.2, depending on weather conditions, and density between 0.975 and 0.980 g/cm3 . When exposed to air for 12 - 24 hours, latex pH decreases to values close to 5.0 and spontaneous coagulation process begins, sepa‐ rating rubber and non-rubber fractions. Rubber fraction can be represented by (C5H8)n, where n is the number of monomers in the chain (between 2, 000 and 10, 000), presenting an average molecular weight from 600, 000 to 950.000 g/mol.

Figure 3 presents the *Hevea brasiliensis* cultivation (a), the bleeding process, in order to collect latex (b), and dry natural rubber, "Brazilian pale crepe" type (*Crepe Claro Brasileiro - CCB*) (c).

#### **1.5. Nanocomposite materials**

Regarding magnetic ceramics, Ni-Zn ferrites stand out and attract scientific community interest, due to its high electrical resistivity, differentiated magnetic properties and several technological applications in electronics, telecommunications and biotechnology [8]. They are generally used in cores of transformers and inductors for high-frequency microwave devices, telecommunication systems and radars, high-speed read and recording magnetic heads, cellular telephony, hospital equipments, among others. In microwave-absorption devices (e.g. electromagnetic interference shielding), absorption capacity may be generated/potentiated by

Tetragonal tungsten bronze (TTB) crystalline structure is considered a structure derived from classic perovskite, where the central octahedral structure BO6 is converted into three different types of cavities, tetrahedral and pentagonal tunnels similar to those found in perovskite structure which are favorable for substitution by cations, and trigonal tunnels are favorable

TTB structure can be described by chemical formula A'2B'4C'4Nb10O30, where A', B' and C' represent different sites on the structure [13]. Depending on the number of sites available, TTB niobates are natural candidates to host structures, due to the possibility of a wide variety of cation substitutions, similar to what occurs with lead zirconate titanate (PbZnTiO3). B' cavity has a cube-octahedral coordination of oxygen atoms; A' cavities have pentagonal prismatic coordinations, while C' cavities have trigonal prismatic coordinations. The size of these cavities decreases following the order A' > B' > C'. In TTB-type compounds, alkali and alkaline earth metals are located at A' and B' sites, while only cations with small atomic radius such as Li are located in C' site. TTB-type compounds with formula A6Nb10O30, A'= Sr or Ba exhibit semicon‐

Niobates with TTB-type structure such as KSr2Nb5O15, NaSr2Nb5O15, KBa2Nb5O15, Na‐ Ba2Nb5O15 and K3Li2Nb5O15 have created interest mainly by high anisotropy of the crystal structure. Among TTB-structure oxides, strontium potassium niobate oxide (KSr2Nb5O15) stands out for being a classic ferroelectric material with Curie temperature close to 430 K[14], belonging to a class of ceramic composites which have great potential application as sensing

Figure 2 shows a representation of strontium potassium niobate oxide structure, with oxygen and niobium octahedra in blue and yellow dark, pentagonal sites with potassium atoms (K1+), tetrahedral sites with strontium atoms (Sr2+) and vacant trigonal sites. This type of structure has two niobium types, which differ from each other by crystallographic position, multiplicity and occupancy factor. Nb(I) leads to NbO6 sites identified by their blue color, and Nb(II) leads to NbO6 sites identified by dark yellow color. The ratio between Nb atoms is 4 Nb(I) to 1 Nb (II).

Latex is extracted from rubber tree stem, more specifically, from lactiferous vessels located in the cortex, and is responsible for bringing food to the tree top. From a chemical point of view,

ductor characteristics which can be incremented when dopants are added.

devices, actuators, memories, transducers, filters and capacitors.

**1.4. Natural rubber**

altering material magnetic or dielectric properties [12].

*1.3.2. TTB structure and potassium-strontium niobate*

416 Leishmaniasis - Trends in Epidemiology, Diagnosis and Treatment

for substitution by smaller cations and anions [9].

As commented by P. M. Ajayan and co-workers [16], the field of nanocomposites involves the study of multiphase material where at least one of the constituent phases has one dimension less than 100 nm. The promise of nanocomposites lies in their multifunctionality, the possibility of realizing unique combinations of properties unachievable with traditional materials. The

**Figure 3.** (a) Rubber tree plantation, *Hevea brasiliensis* species, (b) latex collection process using the bleeding method; detail: storage vessel, and (c) dry natural rubber, "Brazilian pale crepe" type.

challenges associate to this area are immense. They include control over the distribution in size and dispersion of the nanosize constituents, tailoring and understanding the role of interfaces between structurally or chemically dissimilar phases on bulk properties. Large scale and controlled processing of many nanomaterials has yet to be achieved.

An special class of composites and nanocomposites is the one formed by polymer and ceramic materials. In general, choosing a polymer as a matrix or continuous phase is interesting, since many of them have appreciable mechanical and thermal properties. Other properties are also regarded, e.g. hydrophobic/hydrophilic balance, chemical stability and bio-compatibility. The nanometric component is usually inorganic, and called dispersed phase. It can provide high mechanical and thermal stability and novel properties and functionalities that depend on component chemical nature, structure, size and crystallinity [17]. The dispersed phase provides or improves the redox properties, electronic, magnetic, density, refractive index, and others. In most cases, the main features of each of the components present in the nanocomposite is preserved or even improved and, in addition, one can obtain new properties resulting from the synergy of both components. Typical examples of polymer/ceramic nanocomposites of technological interest are formed by ceramic nanoparticles such as barium strontium titanate phase in a matrix with low dielectric loss [18] or nickel-zinc ferrite (Ni0.5Zn0.5Fe2O4 or NZF), dispersed in a polymeric matrix such as vulcanized natural rubber (NR) [19].

When mechanical properties of composites and nanocomposites are investigated, it is seen that the main contribution comes from the polymeric matrix. However, an appropriate nanoparticle engineering and dispersion process can act amplifying, reducing or creating new features in mechanical properties of nanocomposites. Interface and interaction between nanoparticles/matrix exert a significant influence on the mechanical properties, mainly due to the reorganization of chemical bonds and physical attractions of electrostatic nature. Therefore, properties of nanoparticles such as shape, size, surface activity, crystallinity and network microstrain become relevant. Depending on nanocomposites composition, external factors such as temperature, application of electric and magnetic fields can alter and modulate their properties, expanding application options for these materials. Thus, nanocomposites can be used in intelligent membranes, new catalysts and sensors, new generations of photovoltaic and fuel cells, intelligent micro-electronics systems, micro-optical and photonic components, and also therapeutic systems that combine marking, visualization, therapy and control of drug release [20, 21].
