Selective Photonic Disinfection of Cell Culture Using a Visible Ultrashort Pulsed Laser

Irradiation of femtosecond (fs) pulse lasers in the visible and near-infrared ranges have been proposed as a promising approach for inactivating viruses. However, in order to achieve significant virus inactivation, past works have required relatively long irradiation times (1 hour or longer), even for small volumes. Given its advantages compared with other techniques, there is an urgent need to shorten the time required to inactivate viruses using fs laser technology. In this study, we investigate the inactivation of purified M13 bacteriophage in phosphate-buffered saline with large active volume (1 cm 3 ), and short exposure time (several minutes), using lasers with 20 mJ/pulse energy at various wavelengths (800, 400 nm or both 800 and 400 nm combined). For an exposure time of 15 and 2 minute, the use of a 400 nm wavelength laser results in a high load reduction of 5.8 ± 0.3 and 2.9 ± 0.15, respectively, on the log 10 scale of viability. We show that virus inactivation using the 400 nm laser is much more efficient compared with that using an 800 nm laser, or the simultaneous irradiation of 400 and 800 nm lasers. Higher pathogen inactivation is observed for lasers with shorter pulse duration, whereas at longer pulse durations, the inactivation is reduced. For millijoule-energy fs laser irradiation, the M13 bacteriophage inactivation, via the reduction of the functionality of M13 bacteriophages, is accompanied with relatively small amounts of genetic damage. K E Y W O R D Sfemtosecond laser, inactivation, load reduction, M13 bacteriophage

Section: Introductionmentioning

confidence: 66%

Section: Experimental Results Analysis and Discussionmentioning

confidence: 99%

Q_{0} = \frac{\sqrt{π}}{2} \cdot \frac{n α_{1}}{italicck ε_{0}} \cdot \frac{τ_{L}}{ω_{0}} \cdot I_{0} \cdot e^{- \frac{ω_{0}^{2} τ_{L}^{2}}{4}}

((), α_{1} = \frac{true}{\partial α})

Section: Experimental Results Analysis and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Accelerated inactivation of M13 bacteriophage using millijoule femtosecond lasers

Berchtikou

Greschner

Tijssen

et al. 2019

Comparative study on the inactivation of MS2 and M13 bacteriophages using energetic femtosecond lasers

Berchtikou

Sokullu

Nahar

et al. 2020

Femtosecond (fs) laser irradiation techniques are emerging tools for inactivating viruses that do not involve ionizing radiation. In this work, the inactivation of two bacteriophages representing protective capsids with different geometric constraints, that is, the near-spherical MS2 (with a diameter of 27 nm) and the filamentous M13 (with a length of 880 nm) is compared using energetic visible and near-infrared fs laser pulses with various energies, pulse durations, and exposure times. Intriguingly, the results show that inactivation using 400 nm lasers is substantially more efficient for MS2 compared to M13. In contrast, using 800 nm lasers, M13 was slightly more efficiently inactivated. For both viruses, the genome was exposed to a harmful environment upon fs-laser irradiation. However, in addition to the protection of the genome, the metastable capsids differ in many properties required for stepwise cell entry that may explain their dissimilar behavior after (partial) disassembly. For MS2, the dominant mechanism of fs-laser inactivation was the aggregation of the viral capsid proteins, whereas aggregation did not affect M13 inactivation, suggesting that the dominant mechanism of M13 inactivation was related to breaking of secondary protein links. K E Y W O R D S aggregation of the viral capsid proteins, femtosecond lasers, inactivation, mechanism of femtosecond-laser inactivation, MS2 and M13 bacteriophages

Inactivation of multidrug‐resistant bacteria and bacterial spores and generation of high‐potency bacterial vaccines using ultrashort pulsed lasers

Tsen

Popovich

Hodges

et al. 2021

Multidrug‐resistant organisms (MDROs) represent a continuing healthcare crisis with no definitive solution to date. An alternative to antibiotics is the development of therapies and vaccines using biocompatible physical methods such as ultrashort pulsed (USP) lasers, which have previously been shown to inactivate pathogens while minimizing collateral damage to human cells, blood proteins, and vaccine antigens. Here we demonstrate that visible USP laser treatment results in bactericidal effect (≥3‐log load reduction) against clinically significant MDROs, including methicillin‐resistant Staphylococcus aureus and extended spectrum beta‐lactamase‐producing Escherichia coli. Bacillus cereus endospores, which are highly resistant to conventional chemical and physical treatments, were also shown to be effectively inactivated by USP laser treatment, resulting in sporicidal (≥3‐log load reduction) activity. Furthermore, we demonstrate that administration of USP laser‐inactivated E. coli whole‐cell vaccines at dosages as low as 105 cfu equivalents without adjuvant was able to protect 100% of mice against subsequent lethal challenge. Our findings open the possibility for application of USP lasers in disinfection of hospital environments, therapy of drug‐resistant bacterial infections in skin or bloodstream via pheresis modalities, and in the production of potent bacterial vaccines.