Extracellular matrix

Cell anchoring proteins

Artificial cell anchoring

Plasma

PDMS (polydimethyl siloxane)

Synthesis

Biocompatibility

-Chemically inert, non-toxic

-Flexible, soft

-Visibly transparent

-Gas permeable

-Easily processable

-Strong Si-O bonding ~452kJ/mol ex)C-C ~348kJ/mol

-CH3 is hydrophobic

Microfluidics and lab on a chip

-PDMS is the most common material for fabricating microfluidic chips due to its moldability and optical transparency.

-Used for cell culture, organ-on-chip, drug screening, and biosensors.

-Its permeability to gases allows cells to thrive in microfluidic environments.

Organoid: a laboratory-grown, 3D mini-organ-like structure that mimics the key features of a real human organ

Tissue engineering

-PDMS scaffolds can provide mechanical support while allowing nutrient diffusion.

-Surface modifications (e.g., plasma treatment, coating with extracellular matrix proteins) improve cell adhesion.

-Used in vascular grafts, soft tissue implants, and nerve regeneration conduits.

1. Fibrous Capsule Formation

• When PDMS is implanted, the body often responds with a foreign body reaction.
• This leads to a fibrous capsule forming around the implant.

2. Mechanical Issues

• PDMS is soft and elastic, but under long-term stress: It may tear or rupture.

3. Biofouling and Protein Adsorption

• Native PDMS is hydrophobic-> biofilm formation

4. Limited Integration with Tissue

• PDMS is bioinert → it does not bond strongly with bone or tissue.

5. Swelling in Organic Solvents / Lipids

• Although chemically inert, PDMS swells in oils, lipids, or some solvents.

6. Inflammatory / Degradation Issues

• Usually stable, but oxidative degradation (ozone, ROS in vivo) may alter properties.

Medical devices & implants

-Long history of use in catheters, shunts, breast implants, intraocular lenses, and contact lenses.

-Flexible and non-irritating for long-term contact with human tissue.

Catheters

Cerebral shunt

Vessel shunt

Wound healing and dressings

-PDMS films are used as occlusive dressings that are breathable, flexible, and protective.

-Can be incorporated into smart bandages with sensors or drug-release functions.

microneedles

Wearable sensors

Problems

Hydrophobic recovery: even when surfaces are made hydrophilic (via plasma, etc.), PDMS tends to return to hydrophobic state over time. This limits usefulness of modifications.

Small molecule absorption: for drug assays, drug delivery, quantitative measurement in microchannels. Unspecific absorption of hydrophobic molecules distorts results. Mechanical durability: especially when PDMS structures are thin, under load, or under long‐term flow or mechanical stress.

Fabrication limitations: achieving fine resolution in patterning, or combining structures (microchannels, 3D porous scaffolds) with high fidelity and reproducibility.

Future work

Hybrid materials: combining PDMS with hydrogels, more biocompatible polymers, adhesives, or coatings to get the best of both worlds (mechanics + biology).

More permanent surface modifications: e.g., grafting materials instead of only surface oxidation; bulk modifications that give stable functional groups.

Using AI / computational design to optimize microfluidic design or simulate behavior to guide fabrication.

Better standardization for PDMS devices for clinical or commercial translation (e.g. in drug testing, diagnostic devices).

New fabrication techniques (multiphoton lithography, higher resolution 3D printing, etc.) applied to PDMS or PDMS‐based composites.