The Near-Infrared Light Emitted by LiScO2:Cr3+ Phosphor Used to Induce Gland Secretion for Sjogren's Syndrome

Photobiomodulation is promisingly used as a noninvasive new weapon against Sjogren's syndrome, which is a disorder of immune system with two main symptoms of dry eyes and a dry mouth. This work reports a new NIR LED device made from LiScO₂:Cr³⁺ phosphor for the application. The absorbance, internal, and external quantum efficiency of the optimal Li(Sc_0.98Cr_0.02)O₂ phosphor reach 40.9%, 34.5%, and 14.1%, respectively; and the output power and energy conversion efficiency of the LED device packaged using the phosphor driven under 20 mA are 4.23 mW, respectively. The emission spectrum of the LED device can well cover the action spectrum of oxidized Cu_A in cytochrome c oxidase molecules. Both the pathological changes of mice submandibular gland and the expression of human submandibular gland epithelial cells (HSG) in AQP5, M3R andEGR1 confirm that the NIR light has great potential application for treating Sjogren's syndrome. Moreover, study with mice approved that the therapy using the NIR light is more efficient than the conventional medicine treatment using hydroxychloroquine sulfate.