Nanomaterials and Biocompatibility
Tuesday, April 4, 2006
Presented by the Nanobiotechnology Discussion Group
Organizer: David LaVan, Yale University
The Nanobiotechnology Discussion Group meets periodically to explore research at the interface between the biological and chemical/physical sciences in the emerging field of nanoscience. Meetings feature talks from leading junior and senior investigators working in this dynamic and interdisciplinary field.
5:00 pm - 7:30 pm: Presentations
Matthew Becker, National Institute of Standards and Technology, "Measurement Challenges at the Cell-material Interface: Differentiating at the Nanoscale."
David Warheit, DuPont, "Impact of Nanoparticulates on Respiratory Health Effects: Toxicity is Not Always Dependent Upon Particle Size and Surface Area."
Tania Vu, Oregon Health & Science University, "Biomolecule-Tethered Nanoparticle Quantum Dots for Selective Interactions with Neural Cells."
Vicki Colvin, Rice University, "Eco-Nano: The Impact of Engineered Nanomaterials on the Environment."
"Measurement Challenges at the Cell-material Interface: Differentiating at the Nanoscale"
A robust framework outlining the critical interactions that govern the biocompatibility of nanomaterials does not exist, but is desperately needed. New synthetic methods are creating increasingly complex bio- and nanomaterials with regiochemical and stoichiometic control over the functional groups. These materials demand a multidisciplinary approach to identify and develop strategies to both characterize and control cell-material interactions. As the size of the nanomaterial and the corresponding number of bio-molecular interaction sites decrease, high levels of precise characterization are required for meaningful bio-measurements. This presentation will highlight several examples of recent and ongoing research efforts within our group that demonstrate how precise measurements are able to discriminate between species possessing very small physico-chemical variations and how these incremental differences drastically influence the measured biological outcomes.
"Impact of Nanoparticulates on Respiratory Health Effects: Toxicity Is Not Always Dependent Upon Particle Size and Surface Area"
The results of several lung toxicology studies in rats have demonstrated that ultrafine or nanoparticles (generally defined as particles in the size range <100 nm) administered to the lungs produce enhanced inflammatory responses when compared to fine-sized particles of similar chemical composition at equivalent doses. However, the common perception that nanoparticles are always more toxic than fine-sized particles is based upon a systematic comparison of only two particle-types, namely, titanium dioxide and carbon black particles. Apart from particle size and corresponding surface area considerations, several additional factors may play more important roles in influencing the pulmonary toxicity of nanoparticles. These include, but are not limited to: 1) surface treatments/coatings of particles; 2) the aggregation/disaggregation potential of aerosolized particles; 3) the method of nanoparticle synthesis—i.e., whether the particle was generated in the gas or liquid phase (i.e., fumed vs. colloidal/precipitated); 4) translocation potential of the particle; 5) particle shape; and 6) surface charge.
Results of pulmonary bioassay hazard/safety studies will be presented demonstrating that fine-sized quartz particles (1.6 micrometers) may produce greater pulmonary toxicity (inflammation, cytotoxicity, cell proliferation, and/or histopathology) in rats when compared to nanoscale quartz particles (50 nm), but not when compared to smaller nanoquartz sizes (e.g., < 30 nm). In addition, other studies have demonstrated no measurable difference in pulmonary toxicity indices among particle-types when comparing expos