## 1 Introduction  
Polysaccharides are one of the most abundant bioactive inexpensive substances found in nature and have long been used in food, cosmetics, and pharmaceutical industries. Carboxymethyl cellulose (CMC) is the most produced and industrially used water-soluble cellulose derivative [1, 2]. It is commonly produced by a Williamson etherification, with the first step consisting of the modification of cellulose by sodium hydroxide to obtain the sodium cellulose. This is followed by the production of sodium chloroacetate via the dissolution of chloroacetic acid in sodium hydroxide, which will prompt the reaction of the chlorine in the sodium chloroacetate with the sodium cellulosate to produce CMC [3]. By definition, CMC is a copolymer constituted by two units--\(\beta\)-Dglucose and \(\beta\)-D-glucopyranose 2-O(carboxymethyl)-monosodium salt linked by \(\beta\)-1.4-glycoside bonds. The insertion of carboxymethyl groups (-CH\({}_{2}\)-COOH) on the glucose residues in the cellulose backbone improves its interfacial characteristics, providing CMC with a vast array of properties among which are thickener, suspending aid, binder, film-former, gelling agent, stabilizer, water retention agent, protective colloid, and rheology control agent, thus allowing its applicability in very distinctive industries such as food, cosmetic, pharmaceutical, and biomedical [4, 5, 6]. The beneficial inherent properties of CMC, in particular, its lack of toxicity, high stability, pH sensitivity, biodegradability, and biocompatibility, has opened new fields of application with studies showing its potential in advanced fields such as tissue engineering, bone-tissue engineering, and wound dressing [6; 7; 8; 9; 10]. When one considers the industrial applications of CMC there are various patents describing the application in wound dressings [11], drug delivery [12], and cosmetics [13]. For cosmetics in particular, polysaccharides and CMC are widely described as being fundamental for the development of personal care formulations. Their compatibility with other ingredients, safety, and diverse nature (cationic, anionic or amphoteric charge) makes them prime candidates to be modified and incorporated in formulations as moisturizers, hydrators, and emulsifiers [14]. CMC, in particular, has been reported as being used as a rheological modifier for hair conditioners and hair styling products; as a replacer for surfactants in formulations while simultaneously working as an emulsifying, thickening, and stabilizing agent; and as structural ingredient in creams, lotions, and gels [15; 16; 17]. One example in particular has been given by [PERSON] and [PERSON] [15] where CMC, in conjunction with bacterial cellulose, was used as an emulsifier in an oil-in-water generic cosmetic cream and was capable of fully replacing commercial surfactants and maintained rheological properties of the formulations. Another example can be found in the work of [PERSON] and [PERSON] [18] where the use of CMC as a delivery matrix for hydrophilic sunscreens was described. In addition to these structural characteristics, CMC, as polymer, is less sensitive to microbial contaminations than other natural or synthetic gelling agents, thus extending the personal care formulations' shelf life [17]. Taking in consideration the above information, one fact stands out: CMC has always been described as a structural agent valued for its capacity to be compatible with other bioactive ingredients that are responsible for the formulation's biological activity. However, scarce information is available in the literature reporting CMC activity as a bioactive ingredient, and no information at all can be found exploring its potential in the modulation of collagen synthesis or its role in inflammatory response. Moreover, this paper goes beyond the others by trying to establish a correlation between the biological properties screened and the CMC physicochemical and structural properties that were also evaluated here.