Tag Archives: engineered nanoparticles

New method for measuring risks and quantities of engineered nanomaterials delivered to cells

Despite all the talk about testing engineered nanoparticles and their possible effects on cells, there are problems with the testing process which researchers at the Harvard School of Public Health (HSPH) claim to have addressed (h/t Nanowerk, March 28, 2014).

A March 28, 2014 HSPH press release explains the interest in testing the effects of engineered nanomaterials/nanoparticles on health and describes some of the problems associated with testing their interaction with cells,

Thousands of consumer products containing engineered nanoparticles — microscopic particles found in everyday items from cosmetics and clothing to building materials — enter the market every year. Concerns about possible environmental health and safety issues of these nano-enabled products continue to grow with scientists struggling to come up with fast, cheap, and easy-to-use cellular screening systems to determine possible hazards of vast libraries of engineered nanomaterials. However, determining how much exposure to engineered nanoparticles could be unsafe for humans requires precise knowledge of the amount (dose) of nanomaterials interacting with cells and tissues such as lungs and skin.

With chemicals, this is easy to do but when it comes to nanoparticles suspended in physiological media, this is not trivial. Engineered nanoparticles in biological media interact with serum proteins and form larger agglomerates which alter both their so called effective density and active surface area and ultimately define their delivery to cell dose and bio-interactions. This behavior has tremendous implications not only in measuring the exact amount of nanomaterials interacting with cells and tissue but also in defining hazard rankings of various engineered nanomaterials (ENMs). As a result, thousands of published cellular screening assays are difficult to interpret and use for risk assessment purposes.

The press release goes on to describe the new technique (Note: Links have been removed),

Scientists at the Center for Nanotechnology and Nanotoxicology at Harvard School of Public Health (HSPH) have discovered a fast, simple, and inexpensive method to measure the effective density of engineered nanoparticles in physiological fluids, thereby making it possible to accurately determine the amount of nanomaterials that come into contact with cells and tissue in culture.

The method, referred to as the Volumetric Centrifugation Method (VCM), was published in the March 28, 2014 Nature Communications.

The new discovery will have a major impact on the hazard assessment of engineered nanoparticles, enabling risk assessors to perform accurate hazard rankings of nanomaterials using cellular systems. Furthermore, by measuring the composition of nanomaterial agglomerates in physiologic fluids, it will allow scientists to design more effective nano-based drug delivery systems for nanomedicine applications.

“The biggest challenge we have in assessing possible health effects associated with nano exposures is deciding when something is hazardous and when it is not, based on the dose level. At low levels, the risks are probably miniscule,” said senior author Philip Demokritou, associate professor of aerosol physics in the Department of Environmental Health at HSPH. “The question is: At what dose level does nano-exposure become problematic? The same question applies to nano-based drugs when we test their efficiency using cellular systems. How much of the administered nano-drug will come in contact with cells and tissue? This will determine the effective dose needed for a given cellular response,” Demokritou said.

Federal regulatory agencies do not require manufacturers to test engineered nanoparticles, if the original form of the bulk material has already been shown to be safe. However, there is evidence that some of these materials could be more harmful in the nanoscale — a scale at which materials may penetrate cells and bypass biological barriers more easily and exhibit unique physical, chemical, and biological properties compared to larger size particles. Nanotoxicologists are struggling to develop fast and cheap toxicological screening cellular assays to cope with the influx of vast forms of engineered nanomaterials and avoid laborious and expensive animal testing. However, this effort has been held back due to the lack of a simple-to-use, fast, method to measure the dose-response relationships and possible toxicological implications. While biological responses are fairly easy to measure, scientists are struggling to develop a fast method to assess the exact amount or dose of nanomaterials coming in contact with cells in biological media.

“Dosimetric considerations are too complicated to consider in nano-bio assessments, but too important to ignore,” Demokritou said. “Comparisons of biological responses to nano-exposures usually rely on guesstimates based on properties measured in the dry powder form (e.g., mass, surface area, and density), without taking into account particle-particle and particle-fluid interactions in biological media. When suspended in fluids, nanoparticles typically form agglomerates that include large amounts of the suspending fluid, and that therefore have effective densities much lower than that of dry material. This greatly influences the particle delivery to cells, and reduces the surface area available for interactions with cells,” said Glen DeLoid, research associate in the Department of Environmental Health, one of the two lead authors of the study. “The VCM method will help nanobiologists and regulators to resolve conflicting in vitro cellular toxicity data that have been reported in the literature for various nanomaterials. These disparities likely result from lack of or inaccurate dosimetric considerations in nano-bio interactions in a cellular screening system,” said Joel Cohen, doctoral student at HSPH and one of the two lead authors of the study.

Here’s a link to and a citation for the paper,

Estimating the effective density of engineered nanomaterials for in vitro dosimetry by Glen DeLoid, Joel M. Cohen, Tom Darrah, Raymond Derk, Liying Rojanasakul, Georgios Pyrgiotakis, Wendel Wohlleben, & Philip Demokritou. Nature Communications 5, Article number: 3514 doi:10.1038/ncomms4514 Published 28 March 2014

This paper is behind a paywall but a free preview is available via ReadCube Access.

Inaugural workshop using *nanomaterials for environmental remediation being held in Louisiana

Participants at the Nano-4-Rem (nanomaterials for environmental remediation) aNsseRS workshop will be visiting the Southeastern Louisiana University in Hammond in early June 2013. From the Nov.  6, 2012 news item on Nanowerk,

An inaugural workshop on the safe use of nanomaterials in environmental remediation will be held at Southeastern Louisiana University June 5-7, 2013.

With increased use of nanotechnology and nanomaterials in the cleanup of hazardous sites, there is now a growing body of evidence that exposure to these materials may have adverse health effects, said conference organizer Ephraim Massawe, assistant professor of occupational safety, health and environment.

“The applications and results of nano-enabled strategies and methods for environmental remediation are increasingly promising,” Massawe said. “The challenge is ensuring that such applications are both safe and sustainable.”

There is more information on Southeastern Louisiana University’s Nano-4-Rem aNsseRS webpage,

Background: Groundwater or soil contamination is present at most Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and Resource Conservation and Recovery Act (RCRA) corrective action sites. Traditional technologies, such as pump-and-treat (P&T) and permeable reactive barriers (PRBs), have been used for decades to remediate such sites. In recent years, remediation strategies involving engineered nanoparticles (ENPs) such as zero-valent iron and titanium dioxide have been demonstrated as viable time-saving and cost-effective alternatives to traditional remediation. In addition, advances in nanotechnology-enabled assessment and monitoring methods such as nano-sensors may support more extensive, reliable, and cost effective assessment and management of remediation activities.

At the same time that applications of nano-enabled strategies and methods for environmental remediation are increasingly promising, there is a growing body of evidence linking exposure to certain nanomaterials with adverse health effects in animals at the laboratory scale. The challenge is to ensure that such applications are both safe and sustainable. …

Workshop Objectives: This is the first national workshop that provides an opportunity for representatives from the environmental remediation community, industry, academia, and government to:

  • Share their perspectives, pose questions, and develop ideas for design of good guidelines, selection criteria, and work practices to support safe and sustainable nano-enabled environmental remediation;
  • Become acquainted with other U.S. nanotechnology stakeholders, including vendors, transporters, and contractors of the remediation sites and communities; and
  • Share case studies of nano-enhanced clean up technologies, including selection criteria for alternative remediation strategies and methods, job planning, job tasks, and nanomaterial handling practices.

Furthermore, in the context of nanoinformatics (Nanoinformatics 2020 Roadmap), the workshop will present:

  • Occupational and environmental regulatory issues as they relate to remediation, synthesis and characterization, and application of nanoinformatics for safe and sustainable use of nanomaterials during remediation;
  • Fate and transport of nanomaterials during and after remediation;
  • Risks, including contributions from both toxicological properties of nanomaterials (hazard) and potentials for occupational and environmental exposure, where hazard x exposure = risk;
  • Results of the recent nanoinformatics survey of state agencies and programs described on the workshop website; and
  • Opportunities for developing and sustaining continuing advances and collaborations.

Call for Presenters and Deadlines: Participants are invited from the industry; site contractors, nanomaterial vendors; laboratories that synthesize and characterize ENPs for environmental remediation; regulatory authorities (local, state, and federal government) and academia (faculty and students). Presenters should submit titles and abstracts for podium or poster presentations by December 14, 2012. The workshop or program schedule will be finalized by February 20, 2013. Event date: June 5-7, 2013. Students are encouraged to submit proposals for podium or poster presentations. “Best student” poster and presentation awards will be given. Information about this workshop can also be found at http://cluin.org [a US Environmental Protection Agency ‘office’].

The Nov. 7, 2012 news release from Southeastern Louisiana University which originated the news item (Nanowerk seems to have posted the item before the release was posted on the university website) provides more detail,

The event, “Nano-4-Rem-Anssers 2013: Applications of Nanotechnology for Safe and Sustainable Environmental Remediations,” is one of the first of its kind in the Southeast which has been designed to provide an opportunity for involved parties to share perspectives, pose questions and develop ideas for generating solid guidelines for best work practices that support safe and sustainable nano-enabled environmental remediation.

Southeastern is sponsoring the event with other agencies and institutions, including the U.S. Environmental Protection Agency (EPA), the National Institute of Safety and Health (NIOSH), the Occupational Safety and Health Administration (OSHA) and in conjunction with the National Nanotechnology Coordination Office (NNCO).

The program will include case studies of nano-enhanced clean up technologies, including selection criteria for alternative remediation strategies and methods, job planning and tasks, and safe material handling practices. Other issues to be discussed are updates of toxicity studies, fate and transport of nanoparticules [the French word for nanoparticles is nanoparticules ..  this seems an unusual choice for a news release from a US university but Louisiana was French at one time, so perhaps there’s a desire to retain a linguistic link?]  in soils and groundwater, and nanoinformatics.

I have written about nanoremediation before. Here are a few of the latest,

Nanoremediation techniques from Iran and from South Carolina

Canadian soil remediation expert in Australia

Phyto and nano soil remediation (part 2: nano)

* ‘nanotechnolmaterials corrected to ‘nanomaterials’ on Sept. 23, 2013.