Low-intensity red and infrared laser effects at high fluences on Escherichia coli cultures

Abstract

Semiconductor laser devices are readily available and practical radiation sources providing wavelength tenability and high monochromaticity. Low-intensity red and near-infrared lasers are considered safe for use in clinical applications. However, adverse effects can occur via free radical generation, and the biological effects of these lasers from unusually high fluences or high doses have not yet been evaluated. Here, we evaluated the survival, filamentation induction and morphology of Escherichia coli cells deficient in repair of oxidative DNA lesions when exposed to low-intensity red and infrared lasers at unusually high fluences. Cultures of wild-type (AB1157), endonuclease III-deficient (JW1625-1), and endonuclease IV-deficient (JW2146-1) E. coli, in exponential and stationary growth phases, were exposed to red and infrared lasers (0, 250, 500, and 1000 J/cm2) to evaluate their survival rates, filamentation phenotype induction and cell morphologies. The results showed that low-intensity red and infrared lasers at high fluences are lethal, induce a filamentation phenotype, and alter the morphology of the E. coli cells. Low-intensity red and infrared lasers have potential to induce adverse effects on cells, whether used at unusually high fluences, or at high doses. Hence, there is a need to reinforce the importance of accurate dosimetry in therapeutic protocols.

Фототермическое действие инфракрасного (808 nm) лазерного излучения и наночастиц золота в различных модификациях на S. aureus

“…локальной температуры в окрестности наночастицы и средней температуры суспензии представлены в работах [27,28]. Этот механизм лежит в основе повреждений, возникающих в клетке, и влечет за собой ее гибель [1][2][3][4][5][6]10,[23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. В ходе данного исследования показано, что два типа ЗНЧ (нанокубики и наностержни) вызывали дозозависимое сокращение численности бактериальных популяций под действием излучения с мощностью 60 mW/сm 2 .…”

“…Лазерное излучение с интенсивностью порядка 3000−4000 mW/сm 2 способно привести к обезвоживанию, коагуляции белков, изменению заряда молекул, в частности ключевых ферментов клетки. При этом повреждения затрагивают и ДНК, и ферментативный аппарат, необходимый для ее репарации и восстановления [29].…”

Clinical Effects of Laser Acupuncture plus Chinese Cupping on the Pain and Plasma Cortisol Levels in Patients with Chronic Nonspecific Lower Back Pain: A Randomized Controlled Trial

“…The physiological mechanism of LLLT has been adequately established in cellular experiments. LLLT has been used in culture experiments, in which it affects the survival of plasmids in Escherichia coli cells, and DNA repair was produced by pulsed emission modes through low-level infrared laser action [ 25 ]. Furthermore, AlGhamdi et al demonstrated that LLLT is useful in enhancing the proliferation rate of cell lines [ 26 ].…”

Efficacy of single versus multiple exposure by electromagnetic modalities on gram-negative and positive bacterial strains in an in-vitro model

“…LLLT which is commonly known as Low Level Laser therapy is as a potent modality of treatment for controlling the growth of Gram positive and Gram negative bacteria ( Barboza et al, 2015 , Dixit et al, 2019 , Nussbaum et al, 2002 ). As they are low-cost devices and are progressively being used in health care system.…”

“…As they are low-cost devices and are progressively being used in health care system. It is usually postulated that absorption of laser light through chromophores causes alterations in cell physiology eventually leading to cascade of events resulting in cell damage of the bacteria’s ( Barboza et al, 2015 ).…”