Characteristics of Curcumin-Loaded Bacterial Cellulose Films and Anticancer Properties against Malignant Melanoma Skin Cancer Cells  
[PERSON]  
1 Biomedical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand; [EMAIL_ADDRESS] (C.S. ); [EMAIL_ADDRESS] (N.C.)  
2 Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand; [PERSON]DDRESS] (W.W.); [EMAIL_ADDRESS] (S.T.) 3 Department of Materials Science and Technology, School of Engineering, Nagaoka University of Technology, Nagaoka, Niigata 940-2188, Japan  
4 Nanobiomedicine Research Unit, Department of Anatomy, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand; [EMAIL_ADDRESS]  
5 Correspondence: [EMAIL_ADDRESS]; Tel. : +66-221-86875  
using techniques such as irradiation. However, these techniques are energy-consuming [10; 11], and lower energy alternatives are required to make the use of BC gels for drug release economically viable. Due to the high shrinkage that occurs during drying, it has been demonstrated that drugs or active components can be entrapped in BC film, and slowly released as the BC film is rehydrated [12]. Thus, dried BC could be a candidate polymer matrix film for the local slow release of active components. This is a promising method to overcome the problems of degradation of active components by enzymes or acids that commonly occur following oral administration or injection. Skin cancer is a major, global public health problem [13]. Malignant melanoma cases have quadrupled over the 30-year period between 1982 and 2012 [14]. It represents around 4% of all cases of skin cancer, but is responsible for 65% of all deaths caused by skin cancer [15]. The most common risk factors for malignant melanoma are ultraviolet radiation, prolonged childhood sun exposure, aging, family history, and immunosuppression [15]. Current treatment for skin cancer is typically surgery [14]. Curcumin (diferuloylmethane) is one of the bioactive compounds found in turmeric (_Curcuna longa_ Linn). The crude extract of this plant is rich in polyphenols, mostly in the keto or enol forms, such as curcumin, demethylox Curcumin, and bisdemethoxy Curcumin [16; 17; 18]. Extracts of turmeric are used extensively for coloring and flavoring South Asian cuisine, and are also used in alternative medicine. Among the compounds contained in crude turmeric extract, curcumin exhibits outstanding pharmacological activities. For example, the compound has been shown to have anti-inflammatory, antioxidant, antihepatotoxic, antimicrobial, antidepressant, and anticancer properties. It has been reported to kill tumor cells and inhibit the proliferation of cancer cells, primarily through induction of apoptosis. This activity has been observed against malignant cells including: breast [19; 20], thyroid [21; 22], colon [23], leukemia [24; 25], prostate [26], lung [27], ovarian [28] and pancreatic cancer cells [29], as well as malignant melanoma cells [30]. Curcumin has also been shown to inhibit vital processes of cancerous cells, including adhesion, migration, invasion, and spreading. Therefore, curcumin is cytotoxic to cancer cells but not to normal cells. The effects of curcumin entrapped in BC film have not yet been investigated. However, most curcumin is degraded within 30 min at physiological pH [18]. Furthermore, in vivo, low oral bioavailability has been reported in rodents and humans due to degradation by acidic bile and rapid intestinal metabolism [31]. In this study, the potential of BC as a matrix for controlled release of curcumin was evaluated. Curcumin was absorbed into BC pellicles, after which the pellicles were air-dried to produce curcumin-loaded BC films (BCC). The absorption and release characteristics of curcumin from BCC were assessed, and various properties including morphological, chemical, physical, and mechanical properties were characterized.