SMP's patented Plasma Enhanced Chemical Vapor Deposition (PECVD) processes deposit a silicon-based coating on all products. The proprietary PECVD process applies the silica coating to the container in a unit operation where the container is the reaction vessel. This process ensures control of the coating process and simplifies scale-up. Scale-up is achieved by replicating a unit operation. Multiple in-process controls and inspections ensure that each and every product is coated to Six Sigma quality.


SMP's barrier coating is a tri-layer coating system, composed of the following layers:

  • Adhesion
  • SiOx Barrier
  • pH Protective Top Layer


SMP also offers two optional coating layers:

  • Lubricity Coating
    • SMP's lubricity coating allows syringes to be utilized without the use of silicone oil, reducing overall particulates generated
  • Anti-Scratch/Anti-Static Exterior Coating
    • SMP's anti-scratch/anti-static exterior coating reduces the risk of scratching and build-up of static charge, allowing products to be manufactured like their glass counterparts


Benefits to the SMP barrier coating system over glass and plastic include:

  • Coating blocks potential leachables from entering the sample
  • Does not contain the metals found in Type 1 Borosilicate glass, eliminating risk of aggregation and delamination
  • Barrier treatment greatly reduces non-specific protein binding
  • No silicone oil and manufactured in ISO Class 7 clean rooms to reduce particulates with additional Laminar Air Flow above open product to support cleanliness of the product
  • Coating performs well in a wide range of chemical, thermal, and mechanical challenges


SiO2 Medical Products, Inc.'s coating system is deposited onto engineered polymer surfaces in a low pressure PECVD process. The coating is derived from a mixture of a pure siloxane compound and oxygen. The gas mixture is energized to a plasma by applying a voltage drop across two charged electrodes powered by a radiofrequency (RF) power source. The plasma process is driven by electron impact ionization. The use of RF energy to excite the electrons in the plasma results in lower temperatures than other standard methods of energizing electrons, i.e., microwaves.


The plasma places a thin layer of silicon-oxide onto the product's surface during the PECVD process. Electrons and reactive species interact at the polymer surface upon initiation of the plasma by physical or chemical "ablation" of the surface by breaking C-H bonds and ejecting atoms into the plasma. These sites then act as nucleation points where the Si-O-Si backbone (which is formed from the ionization of the siloxane molecule in the gas phase) bonds with the polymer, from which the silica coating grows, eventually forming a uniform, continuous coating over the entire product surface.


The schematic below details the PECVD process when applied using SMP's patented approach:

Above: The syringe is placed into a puck (vessel holder) and a vacuum is established. A mixture of gases is delivered into the evacuated syringe. A radio frequency (RF) electric field is established about the syringe that causes the gas mixture inside the syringe to enter a plasma state (blue glow) initiating the chemical reaction that deposits a coating onto the interior surface of the syringe.

© 2016 SiO Medical Products, Inc.

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