Plasmonic Enhancement of Selective Photonic Virus Inactivation

Abstract

Femtosecond (fs) pulsed laser irradiation techniques have attracted interest as a photonic approach for the selective inactivation of virus contaminations in biological samples. Conventional pulsed laser approaches require, however, relatively long irradiation times to achieve a significant inactivation of virus. In this study, we investigate the enhancement of the photonic inactivation of Murine Leukemia Virus (MLV) via 805 nm femtosecond pulses through gold nanorods whose localized surface plasmon resonance overlaps with the excitation laser. We report a plasmonically enhanced virus inactivation, with greater than 3.7-log reduction measured by virus infectivity assays. Reliable virus inactivation was obtained for 10 s laser exposure with incident laser powers ≥0.3 W. Importantly, the fs-pulse induced inactivation was selective to the virus and did not induce any measurable damage to co-incubated antibodies. The loss in viral infection was associated with reduced viral fusion, linking the loss in infectivity with a perturbation of the viral envelope. Based on the observations that physical contact between nanorods and virus particles was not required for viral inactivation and that reactive oxygen species (ROS) did not participate in the detected viral inactivation, a model of virus inactivation based on plasmon enhanced shockwave generation is proposed.

Accelerated inactivation of M13 bacteriophage using millijoule femtosecond lasers

“…The mechanism of femtosecond laser‐induced virus inactivation is highly wavelength dependent. The wavelength dependence of virus inactivation is also demonstrated in previous studies . In the reported literature, there are many discrepancies between the observed nondestructive or destructive effects caused by similar conditions applied to viruses.…”

“…In studies of such a complex phenomenon, it is difficult to say what the contribution of a particular process is. Moreover, a few processes can cause similar effects , and thus, it is difficult to distinguish which one is more important.…”

“…Of course, the final reaction to continued irradiation of the biological material must always be the same, that is, inactivation of the organism. The effects of the interaction of radiation at different excitation wavelengths with M13 bacteriophage were therefore studied . The mechanism of femtosecond laser‐induced virus inactivation is highly wavelength dependent.…”

Femtosecond photonic viral inactivation probed using solid-state nanopores

“…A part of this variation may be attributed to ~ 15% of the phenol-extracted DNA molecules not being in circular form. The radius of gyration, R g and hydrodynamic radius, R h. of free ΦX174 DNA polymer can be estimated from the known persistence length 2 6 c g P L R = (8) where P is persistence length and L c is contour length. [47][48][49] For ΦX174 DNA with 5386 nucleotides and the persistence length ~4.6 nm for DNA, [50] the R g and R h can be estimated as 72 nm and 45.6 nm, respectively.…”

“…Photonic methods have the potential to provide an attractive alternative to existing biocides and ionizing radiation techniques. [4][5][6][7][8] Photonic inactivation has been successfully achieved with the focused femtosecond (fs) laser pulses for exposure times of ≥ 1h on sample volumes typically of ≤2 ml. [4][5][6][7]9,10] Although the ultrafast laser inactivation method for viral inactivation is fairly well established, a systematic understanding of the inactivation ^ Current address of C. Gillespie: Immunogen, 830 Winter St Waltham MA * wanunu@neu.edu and shyam@bu.edu mechanism, which can contribute to the design and optimization of protocols, is currently lacking.…”