The amniotic membrane, the innermost layer of the placenta, has been used in medical applications for over a century. With its regenerative and anti-inflammatory properties, this biological tissue plays a crucial role in advanced wound care, ophthalmology, and surgical procedures. However, what makes up the amniotic membrane, and why is it beneficial in clinical settings?

Structural Composition Of The Amniotic Membrane

The amniotic membrane is a thin, semi-transparent tissue derived from the placenta after childbirth. It consists of multiple layers, each with unique structural and functional characteristics contributing to its bioactivity. The primary structural layers include:

• Epithelium -A single layer of metabolically active epithelial cells forming the outermost surface.
• Basement Membrane – Rich in collagen types IV and VII, laminin, and fibronectin, providing a scaffold for cell adhesion and migration.
• Compact Layer – A dense, fibrous region containing types I and III collagen, contributing to tensile strength.
• Fibroblast Layer – Contains mesenchymal stromal cells and additional collagen, aiding in matrix formation and modulation of inflammation.
• Spongy Layer—The innermost layer adjacent to the chorion, it is rich in proteoglycans and hyaluronic acid and offers cushioning and anti-scarring functions.

This multilayered architecture makes the amniotic membrane mechanically stable and biologically versatile.

Cellular Components And Their Functions

While the membrane itself is acellular when processed for therapeutic use, in its native state, it contains two main cell types:

• Amniotic Epithelial Cells (AECs) – Located on the epithelial surface, these cells exhibit pluripotent characteristics and contribute to immune modulation and tissue repair.
• Amniotic Mesenchymal Stromal Cells (AMSCs) -Found within the stromal matrix, these cells secrete bioactive molecules that regulate inflammation and promote regeneration.

These native cells are often removed during processing to reduce immunogenicity; however, the growth factors and cytokines they leave behind remain biologically active in processed membranes.

Extracellular Matrix (ECM) And Growth Factors

The amniotic membrane’s extracellular matrix is essential to its regenerative capacity. It consists of:

• Collagens (Types I, III, IV, V, and VII) – These proteins provide tensile strength and structural integrity.
• Elastin – Contributes flexibility and elasticity.
• Laminin and Fibronectin – Facilitate cell adhesion, migration, and organization.
• Proteoglycans and Glycosaminoglycans– Support hydration and create a scaffold for cellular ingrowth.

The growth factors retained in the matrix are equally essential and include:

• Epidermal Growth Factor (EGF)
• Basic Fibroblast Growth Factor (bFGF)
• Transforming Growth Factor-beta (TGF-β)
• Hepatocyte Growth Factor (HGF)
• Vascular Endothelial Growth Factor (VEGF)

These biomolecules aid in modulating inflammation, encouraging angiogenesis, and accelerating tissue remodeling.

Biologic Processing And Product Formats

To prepare the amniotic membrane for clinical application, it undergoes various forms of processing:

• Cryopreservation – Retains more viable biological components but requires cold storage.
• Dehydration – Facilitates room-temperature storage and longer shelf life, though some bioactivity may be reduced.
• Sterilization – Ensures safety for human use without compromising key structural elements.

Processed amniotic membranes are available in different configurations, depending on the intended use and desired properties.

Variations In Membrane Layers And Their Clinical Utility

Different clinical scenarios require membranes with varying levels of durability, bioactivity, and thickness. For this reason, manufacturers now offer amniotic membrane products in multiple-layer formats:

• Single-Layer (Classic)- It is thin and flexible, ideal for ophthalmology and superficial wound care, and is easy to handle and conform to complex surfaces
• Dual-Layer – Offers added tensile strength while maintaining bioactivity. It is Suitable for moderate-depth wounds and surgical grafting.
• Triple-Layer– It provides maximum durability and longevity and is often selected for chronic wounds, deep ulcers, and orthopedic applications where prolonged tissue support is essential.

Layering enhances mechanical resilience without compromising the membrane’s therapeutic potential, giving clinicians more control over treatment outcomes.

Advanced Amniotic Membrane Products

At Acesso Biologics, we offer a comprehensive range of amniotic membrane solutions to meet diverse clinical requirements.

For more information on our amniotic membrane products, contact Acesso Biologics through our Online Form.