NUS Enterprise

Surface Coating with Controlled and Sustained Silver Release for Long-term Inhibition of Infection and Encrustation

Technology #13185n

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Prof. Koon Gee Neoh
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Dr He Cairan (
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Tech Offer 13185n - Silver Release Coating [PDF]

Surface Coating with Controlled and Sustained Silver Release for Long-term Inhibition of Infection and Encrustation


  • Urinary tract infections; Catheters and stents


  • Patent pending


  • Exclusive/ non-exclusive licensing Partnership in commercial development


ILO Ref: 13185

Dr Cairan He ( Industry Liaison Office, NUS Enterprise

Inventor: Prof. Koon Gee Neoh


  • Controlled and sustained Ag release over a course of several weeks
  • Combination of AgNP-PDA and poly(SBMA- co-AAm) layers reduces bacteria adhesion to
  • > 98%
  • Up to 45 days encrustation resist compared to only 6 days for Dover™ silver coated catheter

Technology Overview

Urinary tract infections (UTIs) account for a large proportion of nosocomial infections, and the urinary catheter is the most important predisposing factor. Escherichia coli (E. coli) is one of the most common pathogens found in both catheter- and ureteral stent-associated UTIs. Encrustation induced by urease-producing uropathogens like Proteus mirabilis (P. mirabilis) causes further complications, with an incidence rate of ~50% among patients with long-term indwelling urinary catheters and ureteral stents. Encrustation may result in obstruction of the catheter, and increase the risk of ascending infection (i.e. pyelonephritis), bloodstream infection and death.

Technology Features

We have developed a methodology employing controlled and sustained release of silver for combating bacterial infection and encrustation in urinary catheters over several weeks. Silver nanoparticles (AgNPs) were first coated on polydopamine (PDA) pre-treated silicone catheter surface through the reduction of AgNO3, and this was followed with another PDA coating. The number of AgNP-PDA bilayers can be manipulated to control the amount of silver loaded  and  subsequent  release. Poly(sulfobetaine methacrylate-co-acrylamide) (poly(SBMA-co-AAm)) was then grafted as a top layer to prevent adsorption of biomolecules and bacterial adhesion on the coating surface. The AgNP-PDA coating is of micron thickness, and does not compromise the mechanical properties of the catheters. Bacterial adhesion and biofilm formation assays showed the poly(SBMA-co- AAm) coating reduces adhesion of E. coli by > 97% and P. mirabilis by > 92% on catheter surfaces, and after combination with the AgNP- PDA bilayers, the reduction efficiency is further enhanced to > 98%. With one and two AgNP-PDA bilayers, the coated catheter can resist encrustation for 12 and 45 days, respectively, compared to ~ 6 days of the commercially available Dover™ silver coated catheter. Such anti-infective and anti-encrustation catheters can potentially have a large impact in reducing patient morbidity and healthcare expenditure, and this coating strategy can be similarly applied to other biomedical devices.



Development Status

The coating process has been demonstrated successfully and is readily converted for scale up industrial use. Data is available for demonstration to interested parties.

About the Inventors

Professor Koon Gee Neoh is a professor at Department of Chemical and Biomolecular Engineering National University of Singapore. She has received numerous prestigious awards and honors including Editorial Advisory Board for Langmuir and National Science Award (1996) etc.

Figure 1 Schematic diagram illustrating (A) synthesis of poly(SBMA-co-AAm), (B) steps for modifying silicone catheter surface, and (C) structural layers of P3 coated catheter.