Marasini Sanjay, Dean Simon J, Swift Simon, Hussan Jagir R, Craig Jennifer P
Department of Ophthalmology, Aotearoa New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand.
Department of Ophthalmology, Aotearoa New Zealand National Eye Centre, The University of Auckland, Auckland, New Zealand.
J Photochem Photobiol B. 2025 Feb;263:113091. doi: 10.1016/j.jphotobiol.2024.113091. Epub 2025 Jan 3.
Preclinical studies have confirmed the safety and efficacy of narrowband low-intensity ultraviolet C light (UVC) in managing bacterial corneal infection. To further consolidate these findings, the present study aimed to explore in vitro anti-biofilm efficacy of low-intensity UVC light for its potential use in biofilm-related infections.
Pseudomonas aeruginosa biofilm was grown in chamber well slides for 48 h and exposed to one of the following challenges: UVC (265 nm wavelength, intensity 1.93 mW/cm) for 15 s, 30 s, 60 s or 120 s duration, 70% propanol (positive control), or no exposure (negative control). Bacterial LIVE/DEAD staining was conducted at 1 h, 4 h, 6 h and 8 h after challenge exposures to assess the temporal pattern of biofilm inactivation, and slides were imaged using confocal microscopy. Treatment efficacy was quantified by dead biofilm biomass (volume/area - μm/μm) for different treatment groups at each time point.
At each time point post-exposure, dead biofilm biomass was consistently higher in the alcohol- and UVC-challenged groups than in the unchallenged control (p < 0.05), suggesting a sustained biocidal impact after a given challenge. The quantity of dead biofilm biomass did not differ between UVC groups at any time point (p > 0.05). Observed by confocal microscopy, UVC-exposed biofilm demonstrated predominantly intermediate-stage biofilm (i.e., dying state) at 1 h, which progressed to dead biofilm by 4 h.
Low doses of UVC demonstrated potent anti-biofilm activity, even in exposures as short as 15 s, the dose that has previously been deemed to be effective in managing corneal infection in vivo. These data support the potential for this UVC light-based technology to serve as an affordable, convenient, and effective means of treating ocular infections associated with bacterial biofilm.
临床前研究已证实窄带低强度紫外线C光（UVC）在治疗细菌性角膜感染方面的安全性和有效性。为了进一步巩固这些发现，本研究旨在探索低强度UVC光的体外抗生物膜功效，以了解其在生物膜相关感染中的潜在用途。
将铜绿假单胞菌生物膜在腔室载玻片上培养48小时，然后接受以下挑战之一：波长265nm、强度1.93mW/cm的UVC照射15秒、30秒、60秒或120秒，70%丙醇（阳性对照），或不进行照射（阴性对照）。在挑战暴露后1小时、4小时、6小时和8小时进行细菌活/死染色，以评估生物膜失活的时间模式，并使用共聚焦显微镜对载玻片进行成像。通过计算每个时间点不同治疗组的死生物膜生物量（体积/面积 - μm/μm）来量化治疗效果。
在每次暴露后的每个时间点，酒精和UVC处理组的死生物膜生物量始终高于未处理的对照组（p < 0.05），表明在给定挑战后具有持续的杀菌作用。在任何时间点，UVC组之间的死生物膜生物量数量均无差异（p > 0.05）。通过共聚焦显微镜观察，暴露于UVC的生物膜在1小时时主要表现为中间阶段生物膜（即死亡状态），到4小时时发展为死生物膜。
低剂量的UVC显示出强大的抗生物膜活性，即使在短至15秒的暴露下也是如此，该剂量先前已被认为在体内治疗角膜感染有效。这些数据支持了这种基于UVC光的技术作为治疗与细菌生物膜相关的眼部感染的一种经济、便捷且有效的手段的潜力。
