# A Review of the Synthesis and Applications of Polymer-Nanoclay Composites
## 3 Application
### Biomedical Applications and Drug Delivery  
Advanced nanotechnologies and innovative polymer materials with outstanding properties such as flame retardancy, mechanical, barrier, and thermal properties, have helped create advanced materials at a tremendously fast rate [150]. Cellular interactions with polymer/nanoclay composites have been the subject of recent investigations with a focus on their potential uses in biomedical applications, such as tissue engineering, gene therapy, food preservation, biosensing, bioimaging, and drug delivery [173] (Figure 6). This growing interest is due to the unique properties of polymer/nanoclay composites, including their swelling and rheological properties, high retention capacities, large surface-area-to-volume ratio and affinity for interaction with biopolymers [174]. Tissue engineering is a vital field due to the growth of the aging population and prevalence of chronic diseases. Polymer/nanoclay composites may help to repair and/or replace damaged tissue/organs [175]. For example, polymer/nanoclay-based scaffolds have been successfully implemented in cell-transplantation applications in neural tissue engineering prepared with several advanced strategies and exhibit a high degree of porosity, biocompatibility, and biodegradability [176; 177; 178]. The loading amount of nanoclay in the composite matrix has a substantial effect on the storage and elastic modulus of scaffolds [179; 180; 181]. Moreover, the incorporation of nanotechnology in polymer/clay composites provides strong antibacterial properties, which significantly improves the degradation rate [182; 183; 184; 185]. [PERSON] et al. [186] developed an antibacterial, multilayered polylactic acid/halloysite nanoclay composite membrane encapsulated with gentamicin. A significant enhancement of the membrane's thermal stability and mechanical properties was observed after the incorporation of halloysite nanoclays. The synthesized composite membrane contained porous structures, which indicated its potential use in bone regeneration applications. [PERSON] et al. [187] integrated three dimensional (3D) bioprinting technology to develop a novel, self-supporting, 3D hydrogel/laponite nanoclay composite as an internal scaffold material. The addition of laponite nanoclay effectively improved the mechanical and biological properties of the hydrogel composites, which resulted in a significant increase in the Young's modulus of the scaffold. [PERSON] et al. [188] discussed fundamental insights into polymer/nanoclay hydrogels in biomedical applications, which paved the way for the design of clay-based hydrogel scaffold materials. They investigated the effect of salts (NaCl) and CaCl\({}_{2}\)) on structure and properties of the composites. [PERSON] et al. [189] synthesized an ultra-stiff and thermo-responsive hydrogel material using poly(N-isopropylacrylamide)/nanoclay composites. The developed hydrogel exhibited a high tensile modulus (approximately 3500 kPa) and strength (approximately 1700 kPa), as well as well-defined, thermo-responsive swelling/deswelling behavior, and may potentially be used as a scaffold material. [PERSON] et al. [190] developed a smart composite hydrogel for wound dressing using polyvinyl alcohol/chitosan/honey/clay. The exfoliated nanoclay helped improved the swelling properties and honey-releasing rate of the material. The hydrogel exhibited more than 99% antibacterial activity. [PERSON] et al. [191] synthesized 3D-printed oligomeric poly(propylene fumarate) (PPF) scaffolds, which were observed to be non-toxic to both human mesenchymal stem cells and L929 mouse fibroblasts. Polymer/nanoclay composites also have promising potential in other fields of the biomedical industry such as bioimaging, wound healing, in bio-sensors and as drug delivery agents.