JOURNAL OF COSMETIC SCIENCE 90 noninfective and present in small numbers, Candida can multiply under some circum- stances and cause symptoms requiring medical treatment. Circumstances that promote Candida infection include hormonal changes (5,9,10), medication side effects (5,11), and medical conditions (5,7). The human body inhibits fungal growth through intact skin and other protective mech- anisms, such as naturally occurring long-chain unsaturated fatty acids, pH, competition with normal bacterial fl ora, epithelial turnover, and the desiccated nature of the stratum corneum (11). Other body systems such as the respiratory tree, gastrointestinal tract, and vaginal vault are lined with mucous membranes (epithelium) bathed in antimicrobial fl uids, and some are also lined with ciliated cells that actively remove foreign materials (8,12). Only when these protective barriers are breached can fungi gain access to, colo- nize, and multiply within host tissues. Candidiasis is a primary or secondary mycotic infection caused by Candida, often by the most common Candida species, Candida albi- cans (9). Candida is a dimorphic organism with the ability to convert between the yeast and mycelial fungal forms (10,13). The yeast form is a noninvasive sugar-fermenting or- ganism. The mycelial fungal form produces long root-like invasive hyphae that penetrate the mucosa or skin (14). Vaginitis, thrush (oral candidiasis), esophagitis, gastrointestinal candidiasis, cutaneous candidiasis, diaper rash, paronychia (nail fold infection), and chronic mucocutaneous can- didiasis are all conditions caused by Candida (5,7,8). The clinical manifestations may be acute, subacute, chronic, or episodic. The etiology can be very diffi cult to determine be- cause Candida spp. are commonly recovered from healthy people (5–7,9). Candida has also been implicated as a frequent cause of infant diaper rash (5,7,8). Diaper rash usually begins as a solid patch of red, thickened skin, often around the anus, that can spread to cover the entire groin and lower buttocks. The same moist, warm, closed-off conditions triggering the original rash can also result in skin infection by the yeast. An infected rash can appear as a group of distinct round spots characterized by oozing, crust- ing, or surrounding redness and swelling. Treatment of candidiasis almost always requires the use of antibiotics (11), which can result in the production of antibiotic resistant yeast, extended discomfort until the treat- ment achieves maximum effectiveness, and possibly harmful side effects due to pharma- ceutical toxicity or allergies (11). Therefore, the development of effective physical methods of preventing or treating yeast infections without the use of antibiotics or anti- microbials is highly desirable. Technologies that interfere with the attachment to and invasion of the skin by yeast offer a promising strategy for physical control of yeast activ- ity and prevention of related skin conditions. Candida attaches to skin by three primary mechanisms: hydrophobic interaction (15), electrostatic interaction (4), and ligand interaction (4,12). These reactions may occur independently or in combination at any given moment during substrate interaction (1,15–17). Innovative strategies for disruption of yeast attachment mechanisms, which require a comprehensive understanding of yeast–skin interactions, are essential to the development of improved personal care products. Hydrophobic interactions are weak chemical bonds formed through repulsion of insol- vent molecules by water (18–20), mainly resulting from convergence of nonpolar side chains away from water (18). Hydrophobic interactions promote adherence of Candida to skin (12,15,21) and despite the weak nature of these bonds, their cumulative effect can

RELEASE OF C. ALBICANS FROM SKIN 91 contribute substantially to the attachment of soil or yeast to the skin. Electrostatic inter- actions occur between charge density and distribution on a soil’s surface and inversely charged components on another surface (17,19). Examples of electrostatic interactions include dipole–dipole forces, hydrogen bonds, cationic, and anionic interactions (4,16,22). Molecules with dipole moments attract each other electrostatically by aligning their pos- itive and negative ends in close proximity (23). Hydrogen bonding occurs when a hydro- gen atom is covalently bonded to an electronegative atom and also attracts an additional electronegative atom (5). The attraction created by individual dipole moments and hy- drogen bonding should produce only small changes however, the cumulative effects of simultaneous events may generate signifi cant changes. The biochemistry and structure of biological membranes cause them to be negatively charged (18) therefore, a cationic exchanger should repel yeast and an anionic exchanger should attract yeast, promoting removal from skin. Charge interactions are important to skin cleansing because alteration of the charge affi nity between the soil and cleaning web or solution can increase cleaning effectiveness. This paper describes a method for use of the cationic exchanger carboxymethylcellulose (CMC) to promote enhanced removal of C. albicans from human skin. MATERIALS AND METHODS YEAST CULTURE C. albicans (ATCC 10231) was subcultured using Sabouraud Dextrose (SAB-DEX) me- dium (Becton Dickinson, Cockeysville, MD) overnight at 37°C. The following day, 20 ml SAB-DEX broth was inoculated with 2–3 isolated C. albicans colonies and incu- bated at 32°C for 18 h with shaking at 220 rpm. The broth culture was diluted to 1 × 105 colony-forming units (CFU)/ml with 50 mM sterile potassium phosphate buffer pH 7.2 (VWR Industries, Batavia, IL). VISUAL RELEASE PROTOCOL The following protocol, outlined in Figure 1, was used to measure the effectiveness of various test materials (described in Table I) to induce release of C. albicans adhered to skin tape. Skin tape strips were produced by pulling D-Squame skin-sampling discs (CuDerm Corporation, Dallas, TX) four times from adjacent adult male volar forearm sites. The skin tape strips were placed into deep six-well plates (Becton Dickinson, Franklin Lakes, NJ), and the exposed adhesive was blocked with 2.0 ml of 5% bovine serum albumin (BSA Sigma, St. Louis, MO) in phosphate buffered saline (PBS 150 mM NaCl, 50 mM potassium phosphate, pH 7.4) for 60 min at 33°C while shaking at 220 rpm. The fl uid was removed from each well, the wells washed three times with 50 mM potas- sium phosphate, and 1.0 ml (105 CFU/ml) of C. albicans solution, prepared as described in the previous section, was added to each tape strip. Next, 1.0 ml of trypticase soy broth (TSB Difco Labs, Detroit, MI) was added to each tape strip and the plates were incubated at 33°C for 60 min. The fl uid was aspirated and the tape strips were washed three times with 3.0 ml tris(hydroxymethyl)aminomethane (TRIS)-buffered saline (TBS 50 mM