## 4 Polyphenol-Based Systems and Their Unveiling Potential for Wound Care
### Natural versus Synthetic Polymers for Polyphenol Carrier Design  
The physicochemical properties of a particle wall play a decisive role in its performance. Therefore, certain factors have to be taken into consideration in the selection of coating material, including (i) the ability for providing protection to the core material against the environmental conditions, (ii) the capacity for providing a controlled release of the active compound, (iii) the viscosity (ideally moderated), non-toxicity, and biodegradability of the compound, and (iv) the compatibility between encapsulated and encapsulating (the wall material should be inert toward core active compound) [81,102]. Different polymers have played an important role in the advancement of microencapsulation technology by successfully ensuring the controlled release of active compounds and by providing an intrinsic therapeutic benefit. Both synthetic and natural polymers can be used as encapsulating agents [103,104]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Method** & **Underlying Mechanism** & **Advantages** & **Limitations** & **References** \\ \hline Spray drying & Transformation of a liquid & Simple, flexible, rapid, low operating cost, and easy scaling-up & Limited number of shell materials & \\ Spray drying & feed in dry particles by & technique & available (shell material & \\  & atomizing the feed in a & High encapsulation & must be soluble & \\  & flow of hot air. & efficiency & in water) & \\  & & Easy control of particles properties & Formation of particles & \\  & & & Easy control of particles & and shape \\  & & particles properties & Tendency to particles & \\  & & aggregation & & \\ \hline Liposomes & Hydrophilic–hydrophobic & Efficient controlled & & \\  & interaction between & delivery & Low solubility & \\  & phospholipids and & Either aqueous or & Mainly used on a & [81,92] \\  & water molecules. & lipid-soluble material & laboratory scale & \\  & & can be encapsulated & & \\ \hline Coacervation & Deposition of a liquid & Can be used to & & \\  & coating material around & encapsulate & the complex & \\  & the core material by & heat-sensitive & coacervates are highly & \\  & electrostatic attraction & compounds & unstable & \\  & & & complex method & \\  & & & High production cost & \\ \hline Inclusion encapsulation & Particular nonpolar & & & \\  & molecules are entrapped & & Restricted to nonpolar & \\  & through a hydrophobic & Improvement of & compounds & \\  & interaction inside the & polyphenol stability & High cost of & \\  & cyclodextrin cavity & & cyclodextrin & \\  & replacing water molecules & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Advantages and limitations of some encapsulation methods applicable for polyphenols. Examples of common synthetic polymers used in microencapsulation include poly-lactides (PLAs), polyglycolides (PGAs), and poly(lactide co-glycolides (PLGAs) [105]. As advantages, synthetic polymers are modified more easily, with tunable properties, and can provide greater chemical and mechanical stability and reduced nonspecific protein binding. On the other hand, synthetic polymers can be toxic and non-degradable compounds [105]. Natural polymers have attracted the interest of the scientific community for wound care, such as wound biosensors, drug carrier and delivery systems, tissue engineering, and wound dressings [106]. Contrary to synthetic polymers, biopolymers are biodegradable and present enhanced biocompatibility. In addition, biopolymers allow the adhesion to target tissues, provide a neutral coating with low surface energy, are compatible with the environment, and possess specific receptor recognition [104]. However, there is a considerable level of variability among polymers derived from animal sources. On the other hand, their extraction process can be complicated and costly [103]. Chitosan, hyaluronic acid, and alginate are examples of natural polymers commonly used in microparticulate systems for skin wound dressing and drug delivery [104].