405 nm light exposure of osteoblasts and inactivation of bacterial isolates from arthroplasty patients : potential for new disinfection applications?

McDonald, Richard and Gupta, Sanjay and MacLean, Michelle and Ramakrishnan, Praveen and Anderson, John and MacGregor, Scott and Meek, Dominic and Grant, Mary (2013) 405 nm light exposure of osteoblasts and inactivation of bacterial isolates from arthroplasty patients : potential for new disinfection applications? European Cells and Materials, 25 (March). pp. 204-214. ISSN 1473-2262 (http://www.ecmjournal.org/journal/papers/vol025/vo...)

[thumbnail of 405 nm light exposure of osteoblasts] PDF. Filename: McDonaldGuptaLacleanetal.pdf
Final Published Version

Download (1MB)

Abstract

Infection rates after arthroplasty surgery are between 1-4 %, rising significantly after revision procedures. To reduce the associated costs of treating these infections, and the patients' post-operative discomfort and trauma, a new preventative method is required. High intensity narrow spectrum (HINS) 405 nm light has bactericidal effects on a wide range of medically important bacteria, and it reduced bacterial bioburden when used as an environmental disinfection method in a Medical Burns Unit. To prove its safety for use for environmental disinfection in orthopaedic theatres during surgery, cultured osteoblasts were exposed to HINS-light of intensities up to 15 mW/cm2 for 1 h (54 J/cm2). Intensities of up to 5 mW/cm2 for 1 h had no effect on cell morphology, activity of alkaline phosphatase, synthesis of collagen or osteocalcin expression, demonstrating that under these conditions this dose is the maximum safe exposure for osteoblasts; after exposure to 15 mW/cm2 all parameters of osteoblast function were significantly decreased. Viability (measured by protein content and Crystal Violet staining) of the osteoblasts was not influenced by exposure to 5 mW/cm2 for at least 2 h. At 5 mW/cm2 HINS-light is an effective bactericide. It killed 98.1 % of Staphylococcus aureus and 83.2 % Staphylococcus epidermis populations seeded on agar surfaces, and is active against both laboratory strains and clinical isolates from infected hip and knee arthroplasties. HINS-light could have potential for development as a method of disinfection to reduce transmission of bacteria during arthroplasty, with wider applications in diverse surgical procedures involving implantation of a medical device. With kind permission of full reproduction from eCM journal (www.ecmjournal.org). Founded by scientists for the benefit of Science rather than profit.