Cronin Leah J, Mildren Richard P, Moffitt Michelle, Lauto Antonio, Morton C Oliver, Stack Colin M
School of Science and Health, University of Western Sydney, Campbelltown, NSW, 2560, Australia.
Lasers Med Sci. 2014 Jan;29(1):157-63. doi: 10.1007/s10103-013-1287-4. Epub 2013 Mar 23.
Fungal infection of nails, onychomycosis, is predominantly caused by Trichophyton rubrum. This infection is an important public health concern due to its persistent nature and high recurrence rates. Alternative treatments are urgently required. One such alternative is phototherapy involving the action of photothermal or photochemical processes. The aim of this novel study was to assess which wavelengths within the ultraviolet (UV) spectrum were inhibitory and equally important nail transmissible. Initial irradiations of T. rubrum spore suspensions were carried out using a tunable wavelength lamp system (fluence ≤3.1 J/cm(2)) at wavelengths between 280 and 400 nm (UVC to UVA) to evaluate which wavelengths prevented fungal growth. Light-emitting diodes (LEDs) of defined wavelengths were subsequently chosen with a view to evaluate and potentially implement this technology as a low-cost "in-home" treatment. Our experiments demonstrated that exposure at 280 nm using an LED with a fluence as low as 0.5 J/cm(2) was inhibitory, i.e., no growth following a 2-week incubation (p < 0.05; one-way ANOVA), while exposure to longer wavelengths was not. A key requirement for the use of phototherapy in the treatment of onychomycosis is that it must be nail transmissible. Our results indicate that the treatment with UVC is not feasible given that there is no overlap between the antifungal activity observed at 280 nm and transmission through the nail plate. However, a potential indirect application of this technology could be the decontamination of reservoirs of infection such as the shoes of infected individuals, thus preventing reinfection.
指甲真菌感染，即甲癣，主要由红色毛癣菌引起。由于其持续性和高复发率，这种感染是一个重要的公共卫生问题。迫切需要替代治疗方法。一种这样的替代方法是光疗法，它涉及光热或光化学过程的作用。这项新研究的目的是评估紫外线（UV）光谱中的哪些波长具有抑制作用且对指甲具有同等重要的穿透性。使用可调波长灯系统（通量≤3.1 J/cm²）在280至400 nm（UVC至UVA）波长之间对红色毛癣菌孢子悬液进行初始照射，以评估哪些波长可阻止真菌生长。随后选择了特定波长的发光二极管（LED），以评估并有可能将该技术作为一种低成本的“家庭式”治疗方法来应用。我们的实验表明，使用通量低至0.5 J/cm²的LED在280 nm处进行照射具有抑制作用，即经过2周培养后无生长（p < 0.05；单因素方差分析），而较长波长的照射则没有。光疗法用于治疗甲癣的一个关键要求是它必须能够穿透指甲。我们的结果表明，鉴于在280 nm处观察到的抗真菌活性与透过甲板的穿透性之间没有重叠，所以UVC治疗不可行。然而，这项技术的一个潜在间接应用可能是对感染源进行去污，例如感染个体的鞋子，从而防止再次感染。
