# Modifications of Wound Dressings with Bioactive Agents to Achieve Improved Pro-Healing Properties
## 3 Pro-Healing Wound Dressings
### The Effect of Natural Compounds on Skin Regeneration
#### 3.1.1 Curcumin-Loaded Biomaterials  
Curcumin is a phytochemical belonging to polyphenolic group, occurring in a herb called _Curcuma longa_. It is one of the most active components of herbal turmeric. Due to its antioxidant, hypoglycemic, anti-inflammatory, anti-rheumatic, and antibacterial activity, this natural compound has been studied over the years [52; 53]. Moreover, it is non-toxic and reveals superb biocompatibility, attracting wide interest in many biomedical research fields. However, its poor bioavailability and water solubility have contributed to its limited clinical applications. Nevertheless, curcumin is frequently used in the biomaterial production process, where it is combined with natural or synthetic polymers [54]. Currently, there are many reports in the literature on dressing materials loaded with curcumin. The latest studies concerning the evaluation of the biological properties of curcumin-enriched biomaterials are summarized in Table 1. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Type of** & **Composition of the** & **Experimental Model** & **Biological Properties and** & **Limitations** & **Ref.** \\
**Biomaterial** & **Biomaterial** & **Experimental Model** & **Advantages** & **Limitations** & **Ref.** \\ \hline \multirow{8}{*}{Hydrogel} & \multirow{8}{*}{Curcumin, bacterial cellulose} & In vitro (A549—human & \multirow{8}{*}{Non-cytotoxicity, antibacterial (_S. aureus_) and antioxidant properties} & \multirow{8}{*}{Not provided} [55] \\  & & lung adenocarcinoma, & & & \\  & & MSTO—human & & & \\  & & mesothelioma, & & & \\  & & PANC1—human & & & \\  & & cellulose & pancreatic ductal & & & \\  & & adenocarcinoma, & & & \\  & & U251 MG—human & & & \\  & & glioblastoma, horse & & & \\  & & blood cells) & & & \\ \hline \multirow{8}{*}{Nanofiber} & Curcumin, poly(3- & \multirow{8}{*}{In vitro (I929—mouse & \multirow{8}{*}{Enhanced cell adhesion and proliferation} & Low mechanical \\  & hydroxybutyric & acid-co-3- & & fibroblast cell line) & & \\  & hydroxyvaleric & & & & \\  & acid) (PHBV) & & & & \\ \hline \multirow{2}{*}{Fiber mat} & Curcumin, pure & \multirow{2}{*}{In vitro (HDFa—human & \multirow{2}{*}{Enhanced cell adhesion and proliferation, antioxidant properties} & \multirow{2}{*}{Not provided} [57] \\  & poly-L-lactic & acid (PLLA) & & & \\  & & acid (PLLA) & & & \\ \hline \multirow{8}{*}{Membrane} & Curcumin, chitosan, & \multirow{8}{*}{In vivo (rabbit model)} & Biodegradability, low & \multirow{8}{*}{Dedicated mainly} \\  & polyvinyl & & & & \\  & alcohol (PVA) & & & & \\  & & & & \\  & & & & \\ \hline \multirow{8}{*}{Nanofiber} & Curcumin, polylactic & \multirow{8}{*}{In vitro (I929—mouse & \multirow{8}{*}{An Antibacterial (_E.coli_, _S. aureus_) activity, hydrophobic behavior} & \multirow{8}{*}{Slight toxicity} [58] \\  & & polycaprolactone & & & \\  & (PCL) & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Curcumin-loaded biomaterials for wound healing applications. [PERSON] et al. [55] prepared bacterial cellulose hydrogels with incorporated curcumin (that was entrapped in cyclodext) for potential wound treatment. The biomaterial had the antioxidant potential confirmed by DPPH test, and antibacterial activity was shown against _S. aureus_, associated with its interaction with prokaryotic cell proteins. The hydrogel showed also high water content, which was related to its porous structure, characterized mainly by nanopores (27 nm) and a few large superficial pores (<10 \(\upmu\)m). [PERSON] et al. [56] developed curcumin-loaded nanofiber for wound-healing applications. Biomaterials with different curcumin content (0.1%, 0.3%, and 0.5% \(w/v\)) were produced and tested. It was shown that the reduction in the fiber's diameter (519-207 nm) was directly correlated with the curcumin concentration. Importantly, the highest concentration (0.5% \(w/v\)) of the compound increased cell proliferation and attachment. Nevertheless, high content of the curcumin resulted in decreased mechanical properties due to reduction of the fiber diameter.