Silverlon® and Acticoat® are silver coated polymeric substrates that are applied directly to the wound surface. The fundamental similarity of the Silverlon® and Acticoat® is based upon the biological activity of silver.  The principle differences between Silverlon® and Acticoat® are a direct result of:

• The manner in which the silver is plated to the substrate;
• The geometry and surface area of the plated substrate.

Silverlon® is composed of a silver plated three dimensional fabric that utilizes a proprietary autocatalytic electroless chemical (reduction-oxidation) plating technology while Acticoat® is composed of a silver plated flat polymeric sheet material utilizing a patented vapor deposition plating technology.

 The different plating technique and geometry of the plated substrate results in the following differences between Silverlon® and Acticoat®:

• Differences in the Plated Surfaces
• Differences in the Available Total Silver Surface Area
• Differences in the Release Rates of Ionic and Nonionic Silver
• Differences in Flexibility and Wound Conformability
• Differences in Resistivity

The following eight photomicrographs are scanning electron microscopic (SEM) are views at different magnifications of Silverlon® and Acticoat®.  The first group of four photographs are SEM views of Silverlon® whereas the second group of four photographs are SEM views of Acticoat®.

SEM #1 Silverlon® Fabric	SEM #2 Silverlon® Fibers
SEM #3 Silverlon® Fiber	SEM #4 Silverlon® Surface
SEM # 5 Acticoat®  polymer sheet	SEM # 6  Acticoat® Polymeric Sheet
SEM # 7  Acticoat® Cross-Section	SEM # 8  Acticoat® Nan crystals

The total surface area of metallic silver varies significantly between Silverlon® and Acticoat® based upon the differences in the plating technology and the surface area of the substrates plated.  Silverlon® circumferentially plates ALL polymeric surfaces uniformly while Acticoat® plates only one surface of the flat polymeric mesh that is in line with the direction of the vapor flow.  A simplistic view would be to think of the Silverlon® three-dimensional fabric dipped in a paint solution and the Acticoat® flat mesh sheet spray-painted on one surface from one angle. The second major factor that contributes to the difference in total silver surface area is the variation in the total polymeric surface area of each product.  Comparison of the surface area of the Silverlon® fabric, SEM #1, with the surface area of the Acticoat® polymeric mesh, SEM #5, clearly demonstrates this point.  The total plated surface area of Silverlon® is an estimated 50 times the total plated surface area of Acticoat®.   The construction of the original Acticoat® burn dressings was one layer of rayon/polyester pad ultrasonically welded between two layers of silver coated (one side) polyethylene sheet/mesh.  Therefore, one square centimeter of the three layer Acticoat® dressing is equivalent to an estimated two square centimeters of metallic silver.   The Silverlon® Wound Contact Dressing is a three dimensional fabric, wherein all the filaments of the fabric are 100% circumferentially plated.  Therefore, one square centimeter of Silverlon® Wound Contact Dressing is equivalent to 100 square centimeters of silver surface while one square centimeter of Acticoat® Burn Dressing is equivalent to two square centimeters of silver surface.

The Silverlon® autocatlytic silver plating process, uniformly coats the entire polymeric substrate surface circumferentially.  Consequently, the entire surface of the substrate is covered with a uniform coating of silver.  SEM #1 through SEM #4 demonstrate the circumferential and uniform plating of silver on the Silverlon® dressing.  The Acticoat® vapor deposition plating process coats only one surface in a non-circumferential manner.  The vapor deposition plating technique utilized with the manufacturing of Acticoat® results in a shadowing effect on the polymeric substrate with only one surface coated with a non-uniform layer of silver. SEM #6 shows the flat central hub like structure of the Acticoat® mesh polyethylene substrate.  SEM#7 is an enlargement of a transected central hub with SEM #8 an enlargement of the cut edge, demonstrating the fracturing of the silver plated surface into small (nanocrystaline) silver masses at the transected edge of polyethylene substrate.

 The silver released from the Silverlon® surface is 100% in the ionic (Ag+1) with no silver released in the metallic nanocrystaline form.  The silver released from the Acticoat® surface is ionic (Ag+1) and metal nanocrystaline.  The vapor deposition technique utilized in the manufacturer of Acticoat® creates nanocrystaline clusters on the surface of the plated surface that are easily displaced by mechanical forces.  Quantification of the rate of silver (nanocrystaline and ionic) release has been measured for Silverlon® and Acticoat® in vitro.  The Silverlon® silver release rate was measured in vitro in a specified volume of tryptic soy broth while the Acticoat® silver release rate was measured in water flowing through the Acticoat dressing at a flow rate of 0.33 ml/hour (considered ultra slow) or 7.92 ml per 24 hours.  In 24 hours, Acticoat® (64 cm2) release 40 microgram/ml of water.  In 24 hours, Silverlon® (100 cm2) Wound Contact Dressing released 30 micrograms/ml of tryptic soy broth.  Tryptic soy broth more closely approximated the physiology of a wound than water.  Due to the differing experimental procedures, conclusions are difficult at best.  The silver released from Acticoat® comprised a mix of ionic silver and nanocrystaline species of silver whereas the silver release from Silverlon® comprised only ionic silver.

The flexibility and conformability of Silverlon® and Acticoat® vary based upon the differences between a flat polymeric sheet and a fabric. The Silverlon® fabric is significantly more flexible and achieves better conformation to the wound surface.

Silverlon® is 30 time more conductive that Acticoat® due to the differing plating techniques and continuous surface areas.  The issue of conductivity is important.   Dr. Flick has noted in the clinical setting, that the more conductive a wound dressing the greater the analgesic effect of the product.