Chitosan-TiO2: A Versatile Hybrid Composite

Abstract

In recent years, a strong interest has emerged in hybrid composites and their potential uses, especially in chitosan-titanium dioxide (CS-TiO 2 ) composites, which have interesting technological properties and applications. This review describes the reported advantages and limitations of the functionalization of chitosan by adding TiO 2 nanoparticles. Their effects on structural, textural, thermal, optical, mechanical, and vapor barrier properties and their biodegradability are also discussed. Evidence shows that the incorporation of TiO 2 onto the CS matrix improves all the above properties in a dose-dependent manner. Nonetheless, the CS-TiO 2 composite exhibits great potential applications including antimicrobial activity against bacteria and fungi; UV-barrier properties when it is used for packaging and textile purposes; environmental applications for removal of heavy metal ions and degradation of diverse water pollutants; biomedical applications as a wound-healing material, drug delivery system, or by the development of biosensors. Furthermore, no cytotoxic effects of CS-TiO 2 have been reported on different cell lines, which supports their use for food and biomedical applications. Moreover, CS-TiO 2 has also been used as an anti-corrosive material. However, the development of suitable protocols for CS-TiO 2 composite preparation is mandatory for industrial-scale implementation.Materials 2020, 13, 811 2 of 27 they are synthesized by different methods (intercalation of the polymer, sol-gel, hydrothermal, electro-deposition, chemical and physical vapor deposition, suspension and liquid phase deposition). These methods are effective to enhance the technological and mechanical properties of each individual component and also reveal new functionalities [1,3]. Currently, there is a special interest in combining natural polymers such as chitosan (CS) with inorganic materials like titanium dioxide (TiO 2 ) to obtain hybrid composites (CS-TiO 2 ) with beneficial properties [3][4][5][6].Chitosan (CS) is a natural biopolymer (linear polysaccharide comprising 1-4 linked 2-amino-deoxy-β-D-glucan) generally obtained by deacetylation of chitin, the main structural component of crustacean exoskeletons. CS exhibits a poly-cationic character and is non-toxic and biodegradable [7]. CS is considered a biological functional compound with multiple interesting properties. It can form films for food and pharmaceutical applications, including edible coatings, packaging material, or as drug-eluting carrier [5,7]. Its adsorbent capacity can have environmental applications during photocatalytic processes of waste-water treatment [8], and it also has inherent antibacterial and antifungal properties [9]. It is biocompatible with several organic and inorganic compounds by the presence of free amino and hydroxyl functional groups in its structure, which can react with other functional groups by electrostatic forces, hydrogen bonds, or by compound-soak up into the polymeric matrix, thus improving its mechanical and biological properties [10]...

Electrophoretic Deposition of Gentamicin-Loaded ZnHNTs-Chitosan on Titanium

“…Several recent studies have used coating solutions containing CS and metal nanoparticles. Copper [35], silver [36], titanium dioxide [37], and zinc [38] were the most commonly used metal nanoparticles.…”

Use of Titanium Dioxide (TiO2) Nanoparticles as Reinforcement Agent of Polysaccharide-Based Materials

“…TiO2 has the potential to enhance the properties of polysaccharide-based films such as starch (from potato, corn, and rice), sodium alginate, carboxymethyl cellulose, pullulan, agar, gums (k-Carrageenan, xanthan gum, and gellan), and chitosan, as is discussed below. [1], Miyazaki et al [29], and Tang et al [31]) (Figure created in Biorender.com).…”

“…Thus, their functionalization is necessary [32]. Moreover, nano-TiO 2 can improve the physicochemical ( Figure 2) and functional properties of polysaccharide-based materials like starch, sodium alginate, carboxymethyl cellulose, chitosan, pullulan, agar, k-Carrageenan, xanthan gum, and gellan gum-based materials [1,5,17,[20][21][22]33]. .…”

“…Chitosan is a deacetylated form of chitin with a poly-cationic character and is nontoxic, biodegradable, and biocompatible with organic and inorganic compounds [91]. Recently, a detailed review of the chitosan-TiO 2 hybrid composite has been published [1]. It is a versatile hybrid material with enhanced physicochemical, mechanical, and barrier properties with diversified applications that include antimicrobial, environmental, biomedical, and food and non-food packaging applications [1].…”

“…In recent years, the development of functional and eco-friendly materials with advanced properties as an alternative to replacing conventional nondegradable polymers has gained attention, particularly, for the polysaccharide-hybrid materials which exhibit diversified technological Processes 2020, 8, 1395 2 of 26 applications (antimicrobial agent, packaging material, water pollutant degradation, energy storage, and biosensors) [1,2]. Hybrid materials refer to combining two or more organic or inorganic components such as organic-organic (starch-cellulose), inorganic-inorganic (TiO 2 -Ag), and organic-inorganic (starch-TiO 2 ) compounds, and they are synthesized by different routes such as covalent immobilization, electrostatic binding, and polymerization methods among others [3].…”