_applied sciences_  
_Article_  
An In Vitro Study of the Healing Potential of Black Mulberry (_Morus nigra_ L.) Extract in a Liposomal Formulation  
[PERSON] 1, [PERSON] ([PERSON]) 2, [PERSON] 3, [PERSON] 4, [PERSON] 2,  
[PERSON] 2, [PERSON] 2  and [PERSON] 4,* 4  
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The application of vitamin C to the skin is limited by its hydrophilic property and the hydrophobic skin layer based on an organized lipid matrix. Nanocarriers such as liposomes offer advantages for topical and transdermal application of encapsulated hydrophilic molecules by increasing their solubility and diffusion in the stratum corneum, as well as increasing their stability [13].  
Fibroblasts are the most abundant cells located in the dermal layer, along with other cells of the dermis, such as: fibrocytes, myofibroblasts [14; 15]. A fibroblasts main characteristic is its ability to synthesize and secrete collagen, in addition to remodeling the extracellular matrix and communicating with other cells [16; 17]. Remodeling of extracellular matrix is supported by the synthesis of cleaved metalloproteinases and their inhibitors [16].  
The in vitro evaluation of different extracts or compounds on the wound healing effect, known as the scratch assay, is an easy and inexpensive method that provides valuable information about the biological properties of the tested sample [18; 19]. Also, currently, a major interest consist in the formulation of transport vectors such as lipid vesicles, liposomes or nanoliposomes [20; 21]. The major advantage of liposomal formulas is that they are biocompatible with the human body, for example the use of phospholipids shows major compatibility with the topical applications of these formulations [20; 22; 23]. Another advantage of using these transport systems is that at the level of the dermis they can release the entrapped compounds in a controlled and continuous manner, which allows obtaining a reproducible treatment [24; 25]. In addition, the formulation of liposomes with included extracts allows the protection of biologically active compounds against environmental factors (temperature, humidity, light, etc.) or those related to the human body (pH, enzymes), increasing the effectiveness of the treatment [24]. As a transport system for skin treatment, liposomes have also been shown to have some disadvantages, including their low stability over time, in some instances, their low efficiency of encapsulation, and the need for methods that can be performed easily and reproducibly [26]. In order to rectify these disadvantages, the formulation technique should be adapted according to the compounds to be included in the liposomes [26].  
To our knowledge, the black mulberry extract has never been studied for its in vitro wound healing capacity, both as an extract rich in polyphenic compounds and encapsulated in liposomes. In this context, the first purpose of our study was to characterize the mulberry extract in terms of bioactive compounds (phenolic acids, flavonoids, ascorbic acid) and antioxidant capacity. In vitro testing of the proliferation and healing effect of both forms, the black mulberry extract (MnE) and encapsulated in a liposome (MnL) using the scratch method on normal human dermal fibroblasts (NHDF) was also pursued. The steps of experimental design of our study regarding to the characterization of phytochemical profile of mulberry extract (MnE) and its inclusion in liposomal formulas and in vitro testing of the wound healing is presented in Figure 1.