# Cellulose Nanofibers and Other Biopolymers for Biomedical Applications. A Review
## 4 Outline of Biomedical Applications
### Wound Healing
Commercially available silver products include Aquacel Ag(r), DynaGinate(tm) AG Silver Calcium Alginate dressing and Biatain(r) Alginate Ag [147]. Cross-linked xyloglucan/PVA based hydrogel films investigated for wound healing were found to form a homogeneous, flexible and easy to handle film which showed partial cell adhesiveness and could be applied to the wound and removed without pain. They were fully cyto-compatible, blood-compatible and did not activate an immunogenic response and inhibited _E. coli_ infiltration [149]. Thin xyloglucan-based hydrogel films have been synthesised and characterised with the prospect of producing wound dressings. PVA and glycerol were added to give an optimal combination of softness, conformability and resilience. Physical hydrogels were transformed into permanent covalent hydrogels by reaction with glutaraldehyde. The chemically cross-linked films displayed good cyto-compatibility, and no toxic components were released by the films. Moderate cytotoxicity was observed for the physical hydrogel films. Further investigations on both in vitro and in vivo biocompatibility need to be performed in order to transform this interesting material into a medical device for wound management [150]. Hydrogel-based smart wound dressings that combine the traditional favourable properties of hydrogels as skincare materials with sensing functions of relevant biological parameters for the remote monitoring of wound healing have been investigated. Lightweight, ultra-high frequency radiofrequency identification (UHF RFID) sensors have been combined with xyloglucan/PVA hydrogel films to allow battery-less monitoring of moisture levels [151]. Lignin-PLA combinations have been investigated as wound dressings. The inclusion of lignin yielded materials with lower resistance to fracture and higher wettability and resulted in a material with antioxidant capabilities which would be beneficial for a wound dressing [152]. Biocompatible hydrogels were prepared from chitosan, and alkali lignin were found to be non-toxic to Mesenchymal stem cells, in vitro, and to zebrafish up to 100 ug/mL, in vivo. These gels provided a conducive surface for cell attachment and proliferation, making them suitable for application as scaffolds in tissue engineering. In the presence of the hydrogel,  
Figure 13: Chitosan-alginate nonwovens Composite Wound Dressings. Reproduced with permission from [PERSON] et al. [148]. NIH 3T3 mouse fibroblast cells showed good cell migration characteristics suggesting that the gel might be suitable for wound healing applications [113]. Lignin/chitosan/PVA composite hydrogels were prepared as wound dressings. The introduction of lignin effectively improved the mechanical strength, protein adsorption capacity, and wound environmental regulation ability of the hydrogel. In a murine wound model, the lignin/chitosan/PVA composite hydrogel significantly accelerated wound healing. The novel hydrogel developed also exhibits potential for a wide range of medical applications, such as packaging of expensive drugs [153].