Can biowarfare agents be defeated with light?

Abstract

Biological warfare and bioterrorism is an unpleasant fact of 21st century life. Highly infectious and profoundly virulent diseases may be caused in combat personnel or in civilian populations by the appropriate dissemination of viruses, bacteria, spores, fungi, or toxins. Dissemination may be airborne, waterborne, or by contamination of food or surfaces. Countermeasures may be directed toward destroying or neutralizing the agents outside the body before infection has taken place, by destroying the agents once they have entered the body before the disease has fully developed, or by immunizing susceptible populations against the effects. A range of light-based technologies may have a role to play in biodefense countermeasures. Germicidal UV (UVC) is exceptionally active in destroying a wide range of viruses and microbial cells, and recent data suggests that UVC has high selectivity over host mammalian cells and tissues. Two UVA mediated approaches may also have roles to play; one where UVA is combined with titanium dioxide nanoparticles in a process called photocatalysis, and a second where UVA is combined with psoralens (PUVA) to produce “killed but metabolically active” microbial cells that may be particularly suitable for vaccines. Many microbial cells are surprisingly sensitive to blue light alone, and blue light can effectively destroy bacteria, fungi, and Bacillus spores and can treat wound infections. The combination of photosensitizing dyes such as porphyrins or phenothiaziniums and red light is called photodynamic therapy (PDT) or photoinactivation, and this approach cannot only kill bacteria, spores, and fungi, but also inactivate viruses and toxins. Many reports have highlighted the ability of PDT to treat infections and stimulate the host immune system. Finally pulsed (femtosecond) high power lasers have been used to inactivate pathogens with some degree of selectivity. We have pointed to some of the ways light-based technology may be used to defeat biological warfare in the future.

Evaluation of three different decontamination techniques on biofilm formation, and on physical and chemical properties of resin composites

“…Additionally, CH 3 deformation was observed between 1450 cm 21 and 1380 21 (asymmetric and symmetric stretching). The presence of Si-O-Si and Si-O bonds of the fillers was detected at 1100 cm 21 and 1030 cm 21 .…”

“…13 Gamma radiation can destroy or damage living cells, 16 causes degradation of materials by increasing the temperature of the polymer, and leads to increase of resins degree of conversion. 13,20 UV light has biocide effects (UVC: wavelength between 200 and 280 nm) 21,22 and is also used for the sterilization process, especially for heat sensitive materials. 22 Unlike chemical products, chemical residues or byproducts are avoided, and light is nonpolluting and environmentally friendly.…”

“…UV light has biocide effects (UVC: wavelength between 200 and 280 nm) and is also used for the sterilization process, especially for heat sensitive materials . Unlike chemical products, chemical residues or byproducts are avoided, and light is nonpolluting and environmentally friendly . The inactivation of many microorganisms by UV light is established from the formation of dimers in RNA and DNA .…”

Immune response after photodynamic therapy increases anti-cancer and anti-bacterial effects

“…Also several types of virus have been tested for the affection by PDT, including herpes viruses HSV-1 [97] (PDT by methylene blue and light), enveloped RNA viruses from two different families, Semliki Forest Virus ( Togaviridae ) and vesicular stomatitis virus ( Rhabdoviridae ) (PDT by buckminsterfullerene and light) [98] and others [99] .…”

Antimicrobial and anti-biofilm activity and biological decontamination efficiency of ED-1 emulsion

“…The first step in neutralizing biological warfare agents is disinfection, or in other words, treatments that can destroy or neutralize the agent in a wide range of inorganic, organic, or living environments before the agent has had a chance to come into contact with human beings in a sufficiently large dose to cause infection of harm. 7 Decontamination, aimed at eliminating the hazard biological warfare agents, is required on the battlefield as well as in laboratories, and biological agent production, storage, and destruction sites. Many current decontaminating formulations are effective, but they require the use of strong oxidizing agents or organic solvents that have deleterious effects on human health and the surrounding environment.…”