Many consumer products are applied to the skin or hair, and/or involve the sensory experience of touching. Consumer preferences are influenced by a multitude of factors, including product effectiveness, the feel of the product, fragrance, durability, ease of rinsing, etc. One way to determine consumer preferences is by conducting consumer marketing tests, in which a representative group of consumers, or panelists, provide feedback after using a product. Consumer marketing tests have several drawbacks, however. Because panelists must be appropriately selected and compensated for their time, such tests are expensive and time consuming. Human feedback is inherently subjective, and may raise concerns about reliability. Products must be safe for human testing, and the analyses that can be performed after application also are limited.
Some product testing can be performed using model systems. Artificial substrates are available that, to some extent, imitate human skin. For example, theatrical performers often transform their appearance by using molded body parts that can be made to look remarkably like human skin. Alternatively, keratinous tissue from animals or human cadavers may be used. Whereas these and other available models may be suitable for some types of product testing, all have significant limitations. Cadaver tissue is costly, and neither cadaver nor animal tissue can truly mimic living, human tissue. Artificial substrates are poorly suited to assess characteristics such as product adsorption, rinseability, elasticity and compressibility. Many substrates absorb water and/or decompose, and thus cannot be effectively cleaned or reused. Currently available models also fail to reflect differences in skin on various parts of the body, in different environments, and between different individuals, which may be critical in developing certain personal care products. Characteristics of skin on, for example, one's face, fingertips, palms of the hand, heels, and underarms tend to differ dramatically. The skin of babies and young children differs from the skin of adults, and skin having hair differs from non-haired skin. In summary, to date no suitable substrate is available that can reproduce complex properties of various types of keratinous tissue that are relevant to a wide range of products.
There exists a need, therefore, to provide a more suitable model of a range of types of mammalian keratinous tissue for testing consumer products, which is capable of reproducing a wide range of properties most relevant to a given product, and which can reduce the need for testing with human subjects.