Animal testing has been a contentious issue for many years, with ethical concerns about the treatment of animals in research settings. While animal testing has contributed to significant advancements in medicine and science, there is growing recognition of the need to minimize and, whenever possible, eliminate the use of animals in research.
Luckily, the development of artificial skin-tissue equivalents is a rapidly advancing field with profound implications for various applications in medicine and beyond. These artificial skin models aim to replicate the structure, function, and properties of native human skin as closely as possible.
Accurately mimicking the structure and function of human skin is indeed a complex task. These “skin-equivalents” must replicate not only the outermost layer (epidermis) but also the underlying dermis, including its various cell types, extracellular matrix components, blood vessels, and nerve endings.
Moreover, these models need to exhibit similar properties to human skin, such as absorption, irritability, elasticity, strength, and the ability to repair wounds. Achieving all of these characteristics requires interdisciplinary collaboration among scientists specializing in cell biology, tissue engineering, biomaterials, and more.
However, despite the challenges, significant progress has been made in developing skin-equivalents that closely resemble human skin. These models have already found applications in various fields, including drug testing, cosmetics development, and wound healing research. Continued advancements in bioengineering techniques and materials science are expected to further improve the accuracy and reliability of artificial skin models, making them indispensable tools in biomedical research and clinical practice.
Bioengineered Skin and its future applications
Bioengineered skin consists of an outer epidermal layer and/or a dermal layer (the layer of skin between the epidermis and the subcutaneous tissue) embedded into an acellular matrix (a support structure), forming a biological skin substitute.
By culturing keratinocytes on a dermal substitute containing fibroblasts embedded in an extracellular matrix, researchers can mimic the structure and function of human skin more closely. The fibroblasts represent the dermal layer, providing structural support and contributing to the extracellular matrix, while the keratinocytes form the epidermis, the outermost layer of the skin responsible for barrier function and protection.
Exposing the constructs to air to induce cell differentiation further enhances their similarity to natural skin, allowing researchers to study processes such as epidermal differentiation and barrier formation. This differentiation process typically takes 10 to 14 days, after which the constructs can be maintained in culture for an additional one to two weeks to conduct various tests.
These models provide a more accurate representation of human skin compared to traditional 2D cultures, allowing researchers to better assess the efficacy and safety of new cosmetic formulations. Moreover, their reproducibility and translatability to humans make them invaluable tools, reducing reliance on animal testing while providing valuable insights into cellular interactions within tissue-like structures. As such, 3D skin models not only benefit the cosmetic industry by facilitating product development but also hold promise for broader applications in medical research, contributing to advancements in dermatology and beyond.
In reality, the submission of numerous 3D skin model manufacturers to the European Center for the Validation of Alternative Methods (ECVAM) reflects the growing interest and investment in alternative methods for cosmetic testing. ECVAM plays a crucial role in validating these models to ensure their reliability, relevance, and applicability for regulatory purposes.
The approval of some commercial skin models by the Organization for Economic Co-operation and Development (OECD) further underscores their acceptance and recognition at an international level. OECD validation signifies that these models meet rigorous scientific standards and can be utilized for cosmetic risk assessments in compliance with regulatory requirements.
This validation and approval process not only enhances confidence in the use of 3D skin models but also promotes their adoption as viable alternatives to traditional animal testing methods. By facilitating the use of validated models, regulatory bodies contribute to the advancement of humane and scientifically robust approaches to cosmetic safety assessment.
Ultimately, these advancements pave the way for the creation of safer and more efficacious beauty and dermatological products. By better understanding how formulations interact with human skin at a cellular level, researchers can identify potential risks and optimize product formulations to enhance safety and efficacy. This not only benefits consumers by offering products that are more tailored to their needs but also contributes to the overall advancement of cosmetic and dermatological science.
