**1. Introduction**

Clay nanoparticles are natural materials in nanoscale that originate from clay. They have attracted much attention in recent years due to their widespread applications. The interest in exploiting clay nanoparticles for various purposes is due to their high surface and unique physical and chemical properties.

In 2013, a group of researchers focused on clay nanoparticles as a drug delivery system. Preparation, physical/chemical properties, and bioaccumulation of clay nanoparticles based

> © 2016 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. © 2018 The Author(s). Licensee IntechOpen. 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.

on drug delivery systems, as well as their application in the food system as a nanocarrier for vitamins, antioxidants, linoleic acid, and the other foods, were discussed [1]. In addition, studies have shown that nanotechnology will revolutionize the food industry [2]. Nanoscale food control can lead to the correction of micromolecular properties of foods such as taste, aroma, texture, sensory characteristics, processing ability and stability throughout the process, and storage. Nanotechnology applications grow rapidly in the food and ingredient sector. Advanced nanoelectronics, in combination with good nanomaterials and intelligent biological components, are able to develop very specific and selective measuring devices to identify potentially hazardous agents, including viruses, pathogenic microorganisms, as well as inappropriate physical and chemical substances in foods [3–5]. The micro/nanotechnology accelerates the decreasing size of the sensor to the extent appropriate for application (applied field) [6–8].

**2. Delivery efficiency and biocompatibility of clay nanoparticles**

sixfold coordination with oxygen from the tetrahedral sheet and with hydroxyl.

Nanoclays are fine-grained crystalline materials. A layer is the basic structural unit of nanoclays, and these layers are prone to arrange themselves over one another like pages of a book. Individual layers are composed of the tetrahedral and/or octahedral sheets, and this arrangement of sheets plays a vital role in defining and distinguishing these clay minerals. In tetrahedral sheet, the silicon-oxygen tetrahedra are linked to neighboring tetrahedra by sharing three corners while the fourth corner of each tetrahedron forms a part to the adjacent octahedral sheet. The octahedral sheet is usually composed of aluminum or magnesium in a

Development of Clay Nanoparticles Toward Bio and Medical Applications

http://dx.doi.org/10.5772/intechopen.77341

169

Clay layer nanoparticles are divided into two different types of anion and cation depending on the level of layer charge and the types of interlayer ions. Anionic layer nanomaterials typically have been created by double-layered hydroxides (LDHs) with alterable anions in interlayer spaces. LDHs include a wide range of chemical compounds and their layered structure that can be of a great variety to produce poly-types. For example, aluminosilicate cationic nanoparticles like montmorillonite (MMT) have octagonal and quadrilateral plates with high internal surfaces. The main structure of cationic clays is based on a framework, where the unit structure is composed of an octagonal-twisted sheet between two quadrilateral plates. In **Figure 2**, the structure of the double-layer hydroxide and cationic clay (MMT) is presented.

Therefore, cationic and anionic clay nanoparticles can be applied as transfer carriers, which

In general, clay nanoparticles are considered as biodegradable materials. In fact, cationic minerals have traditionally been applied in a variety of fields including skin chemotherapy, laxatives, antidiarrhea, and anti-inflammatory agents as well as antimicrobial agents [40–42]. Recently, they are used as lubricants and distributary in pharmaceutical programs to improve chemical, physical, and organoleptic properties [43–45]. MMT can be considered as an

depend on the charge of molecules and essentially on their unique layered structure.

**2.1. Structural and physical properties of nanoclays**

**Figure 1.** A scheme of clay-layered nanomaterial systems [1].

**2.2. Structural features**

**2.3. Biocompatibility**

In addition to ensuring food safety, nanotechnology improves our lives by monitoring quality and nutrition status [9, 10]. Food packaging is another area that has used nanomaterials to increase the shelf life of the food by improving the preserving properties. Nylon-based nanocomposites are currently used to produce beverage bottles in Korea and the United States [11]. Polymer nanoparticles are made by dispersing nanoparticles into a polymer matrix [12]. For example, nylon/silicate nanocomposite containing 2% non-mineral nanoparticle has two times higher tensile strength and thermal stability (at a temperature above 100°C) than pure nylon [12]. Nylon-based nanocomposites are formed by the dispersion of silicate layers on a continuous polymer matrix. This structure significantly reduces the amount of oxygen or carbon dioxide release (diffusion) in encapsulation, since these gases should be distributed through the space between dispersed nano-silicate layers [13]. Properties such as strength and thermal stability make this nanocomposite ideal for packaging food. Several attempts and experiments have been carried out to provide various types of antioxidants, nutrients, minerals, drugs, and other applicable factors through food [14]. Currently, most efforts to develop delivery systems focus on drugs. While safety and cost concerns are one of the most important factors in choosing food for the customer, high production costs of drug delivery systems are still acceptable in medicine. Clay nanoparticles are minerals in clay that have attracted much attention due to the biological application of their abundance in nature, simplicity of construction, and biocompatibility [15–18]. Clay nanoparticles also have a great potential for nutrition because they have been used to treat and protect as a traditional medicine since the beginning of human civilization [19–21]. Clay minerals have been used as laxatives, antidiarrhea, antiinflammatory agents, blood purification, reducing infections, and healing of stomach ulcers [22]. In addition, biocompatible clay minerals are currently used as oral antioxidants [23, 24]. Clay nanoparticles have unique layer structures, including the accumulation of nanoparticles with metal ions and intracellular ions for charge balancing [25]. The two-dimensional (2D) structure illustrates interesting strategies for the development of new nano-hybrid systems by enhancing active biochemical molecules into space (**Figure 1**). Intrinsically, unstable agents can be protected against processing conditions and hard-working environment and ultimately released with a controlled pattern in a desirable environment [26–28]. Many studies have shown that nano-layered materials can encapsulate DNA [29, 30], nucleotides [31, 32], drugs [33, 34], proteins [35], and even viruses [36]. These nano-hybrid systems are designed to enhance the efficient delivery to cells and the effectiveness of biochemical molecules [37–39]. However, the application of nanoscale materials to nutrients delivery is very limited.

**Figure 1.** A scheme of clay-layered nanomaterial systems [1].
