NanoMask Testing

The reason we currently choose to test at Nelson Laboratories:

Introduction

The National Institute for Occupational Safety and Health (NIOSH) is the federal agency responsible for conducting research and making recommendations for preventing work-related injury and illness. Their headquarters is in Washington, DC, and their research offices and laboratories are in Cincinnati, OH, Morgantown, WV, Pittsburgh, PA, Spokane, WA and Atlanta, GA. NIOSH utilizes a staff of over 1,400 employees from a wide range of disciplines including medicine, epidemiology, medicine, hygiene, safety, psychology, engineering, statistics, and chemistry.

Nelson Laboratories provides high quality testing to manufacturers in the medical device, nutraceutical and pharmaceutical industries since 1985. They manage a 62,000 square feet FDA registered facility in Salt Lake City, UT where they maintain eightty laboratories along with a custom-built 3,000 square feet cleanroom and employ over 170 scientists and staff. Among their more than 75 degreed scientists are over 25 registered and specialist microbiologists (National Registry of Microbiologists), they currently offer more than 400 microbiological and analytical tests and are 3rd-party certified to ISO 9001 (BSI) and EN 45001/IEC/ISO 17025 standards accredited (AMTAC).

Technology Validation

Filtration efficiency is the measurement of a filter’s capacity to remove particulates, such as bacterium and virus, from moisture or air over a specified period of time. Filtration efficiencies are determined by testing filter media, at a specified flow rate, for penetration by an aerosol with a mean particle size of 0.3 microns. The aerosol testing is commonly performed on various types of filter media to measure efficiency and the test procedure is usually structured in one of two ways; aerosol only and aerosol with viral or bacterial challenge organism.

NIOSH tests N-series against a mildly degrading aerosol sodium chloride (NaCl), and R-series and P-series filters against a highly degrading aerosol of dioctylphthalate (DOP). NIOSH does not currently test filters against any type of challenge organisms and do not offer such testing as an option. Also, NIOSH has acknowledged that their aerosol-only test is incapable of measuring the effectiveness of nanoparticle enhanced filter media.

Nelson Laboratories is able to offer both BFE and VFE testing and as a highly respected independent testing facility their results are accepted by both the U.S. Military and FDA. In addition, the BFE and VFE test procedures can be modified to include a variety of challenge organisms and are effective in evaluating nanoparticle enhanced filters.

The FDA doesn't accept aerosol-only tests as a validation of filtration efficiency for filters incorporated into Class II medical devices or filters used in conjunction with respiratory equipment. They require satisfactory results from BFE (Bacterial Filtration Efficiency) or VFE (Viral Filtration Efficiency) as a validation of filtration efficiency. The U.S. Military also requires satisfactory results against specific viral and bacterial organisms.

This is not intended to denigrate NIOSH, for whom we have the utmost respect, but we currently utilize Nelson Laboratories for two principal reasons: 1) Nelson Laboratories are able to validate filtration efficiencies against biological contaminates. If we were concerned solely with the removal of aerosol or very large particulates the NIOSH test would acceptable, but that is not the case. We are concerned with potentially harmful pathogens that are transmitted by aerosol and want to ensure our filters are effective against viral sized particulates. Therefore, we have chosen to test to a medical standard as we make no distinction between filters intended for medical use and filters intended for personal protection. 2) Nelson Laboratories is able to accurately measure the effectiveness of various nanoparticle solutions on a wide range of specified virus and bacterium.

Why Enhanced Filters are Important

NanoMask prototypes containing nanoparticle enhanced filters were tested at Nelson Laboratories. The challenge organism utilized in the testing was Bacillus thuringiensis, a closely related bacterium to Bacillus anthracis, the cause of lethal anthrax disease. Bacillus anthracis is considered too dangerous to use in the type of study so Bacillus thuringiensis is used because it demonstrates similar spore forming characteristics to Bacillus anthracis and is genotypically and phenotypically very similar.

Test materials included untreated samples and samples treated with reactive nanoparticles placed on the filter surface. After twenty-four hours, the untreated test samples showed a 6507% increase in bacterial CFU (colony forming units), while samples treated with minimum of nanoparticles showed a 21.68% reduction of bacterial CFU. This preliminary testing clearly shows pathogens filtered from airflow continue to ‘live’ and reproduce on the filter, resulting in an increase of the associated risk factors. The testing also indicates that nanoparticles are effective in eradicating pathogens on the surface of the filter media. Subsequent testing of various nanoparticles solutions was conducted in conjunction with EFP’s work to develop filter media for the United States Military. The tests were funded by a Prototype Develepment /Testing / Evaluation Grant by the Center for Commercialization of Advanced Technology awarded in September 2004. The testing was performed against specific pathogens which necessitated the use of Nelson Laboratories in order to validate results.

NIOSH Protocol

Under NIOSH criteria, the filter materials for respirators are tested at a flow rate of 85 L/minute for penetration by particles with median diameter of approximately 0.3 um. Three categories of filter (N, R, and P) are designated, each with three levels of filter efficiency (95%, 99%, 99.97%) for a total of nine respirator classes. The three levels of filter efficiency consist of Type 100 (99.97% efficient), Type 99 (99% efficient), and type 95 (95% efficient). The classes of these particulates respirators certified under this classification are described in 42 CFR Part 84 Subpart K. N-series filters are tested against a mildly degrading aerosol of sodium chloride (NaCl). R-series and P-series filters are tested against a highly degrading aerosol of dioctylphthalate (DOP). Type 95, Type 99 and Type 100 respirators are approved for use against particulates by NIOSH and accepted by OSHA for appropriate use in every work environment.

Nelson Laboratories Protocols

Viral Filtration Efficiency (VFE) and Bacterial Filtration Efficiency (BFE) tests are commonly performed on various types of filter media designed to provide protection against biological aerosols. The VFE and BFE test procedures were designed after Military Specification 36954C. The aerosol challenge mean particle size [MPS] is tightly controlled and challenge aerosol particles are sized using a six-stage viable particle Andersen sampler permitting stage by stage analysis. The aerosol is then directed into a glass aerosol chamber and drawn through the filtration media and into a six-stage Anderson sampler for quantitation. The flow rate of the aerosol is maintained at 1 CFM (cubic feet per minute) or 28.3 LPM (liters per minute). The number of viral or bacterial aerosol droplets contacting the filter media is determined by conducting tests without filter medium in the test system. These challenge control are maintained between 1700-2700 CFU (colony forming units) or PFU (plaque forming units).

The Bacterial Filtration Efficiency test is conducted using Staphylococcus aureus as the challenge organism. S. aureus organisms are gram positive cocci (spherical) with approximate diameters of 0.8 microns. The VFE test is conducted using Bacteriophage OX174 as the challenge organism. Bacteriophage range in size from 0.025 to 0.027 microns. Liquid suspensions of S. aureus and Bacteriophage pump into a “Chicago” nebulizer, which disperses the suspension into small aerosol droplets. The dispersion is polydispersed. The test pressure and challenge flow rate in the nebulizer are consistently maintained to provide an aerosol with a mean particle size of 3 um.

NanoMasks - Avian Flu Tests - Time Kill Study - H5N1 - NanoMask