- Polydimethylsiloxane (PDMS) is a widely used silicone-based polymer known for its unique combination of flexibility, optical clarity, biocompatibility, and chemical stability. Structurally, it is composed of a repeating siloxane backbone—alternating silicon and oxygen atoms—with methyl groups attached to the silicon atoms. This configuration gives PDMS a high degree of molecular mobility and imparts the material with rubbery elasticity and low surface energy, making it ideal for a variety of industrial, medical, and scientific applications.
- PDMS is thermally stable, hydrophobic, and chemically inert, which makes it resistant to weathering, oxidation, and degradation by most chemicals. It remains stable over a broad temperature range and exhibits excellent insulating properties. These characteristics, combined with its transparency to visible light and non-toxicity, make PDMS particularly valuable in optics, electronics, and biological research. It is also gas-permeable, which is beneficial for cell culture applications that require oxygen and carbon dioxide exchange.
- In the biomedical field, PDMS is a cornerstone material for the fabrication of microfluidic devices, especially Organ-on-a-Chip platforms. Its ability to be easily molded using soft lithography techniques allows researchers to create complex microchannel networks that mimic blood vessels, tissues, or entire organ systems. PDMS can be irreversibly bonded to glass or other PDMS layers to create sealed devices, and its transparency enables real-time optical microscopy of cells and fluids within the system. Additionally, its biocompatibility and low cytotoxicity make it suitable for direct contact with living cells and tissues in vitro.
- Beyond research, PDMS is used in a broad array of consumer and industrial products, such as sealants, lubricants, cosmetics (especially in hair and skin products), medical implants, and food-grade tubing. Its flexibility and resistance to microbial growth also make it ideal for applications in prosthetics, catheters, and other medical devices. In dentistry and dermatology, PDMS-based materials are used for impression molds and topical formulations, respectively.
- Despite its versatility, PDMS has some limitations. Its hydrophobic nature can lead to nonspecific adsorption of proteins and small molecules, which may interfere with biological assays or drug delivery studies. To mitigate this, surface treatments (such as plasma oxidation or chemical coatings) are often applied to render the surface temporarily hydrophilic. Additionally, its mechanical properties can degrade over long-term use or under high-stress conditions, and its tendency to absorb small hydrophobic molecules can affect analytical sensitivity in some microfluidic applications.
