Disposition of Fluorine on New Firefighter Turnout Gear.

Firefighter turnout gear is essential for reducing occupational exposure to hazardous chemicals during training and fire events. Per-and polyfluoroalkyl substances (PFASs) are observed in firefighter serum, and possible occupational sources include the air and dust of fires, aqueous film-forming foam, and turnout gear. Limited data exist for nonvolatile and volatile PFASs on firefighter turnout gear and the disposition of fluorine on the individual layers of turnout gear. Further implications for exposure to fluorine on turnout gear are not well understood. Three unused turnout garments purchased in 2019 and one purchased in 2008, were analyzed for 50 nonvolatile and 15 volatile PFASs by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-qTOF-MS) and gas chromatography-mass spectrometry (GC-MS), respectively. Particle-induced gamma ray emission (PIGE), a surface technique, and instrumental neutron activation analysis (INAA), a bulk technique, were used to measure total fluorine. Bulk characterization of the layers by pyrolysis-GC/MS (py-GC/MS) was used to differentiate fluoropolymer (e.g., PTFE) films from textile layers finished with side-chain polymers. The outer layer, moisture barrier, and thermal layers of the turnout gear all yielded measured concentrations of volatile PFASs that exceeded nonvolatile PFAS concentrations, but the summed molar concentrations made up only a small fraction of total fluorine (0.0016-6.7%). Moisture barrier layers comprised a PTFE film, as determined by py-GC-MS, and gave the highest individual nonvolatile (0.159 mg F/kg) and volatile PFAS (20.7 mg F/kg) as well as total fluorine (122,000 mg F/kg) concentrations. Outer and thermal layers comprised aromatic polyamide-based fibers (aramid) treated with side-chain fluoropolymers and had lower levels of individual nonvolatile and volatile PFASs. Equal concentrations of total fluorine by both PIGE and INAA on the outer and thermal layers is consistent with treatment with a side-chain fluoropolymer coating. New turnout gear should be examined as a potential source of firefighter occupational exposure to nonvolatile and volatile PFASs in future assessments.

Fabrication of {198Au0} radioactive composite nanodevices and their use for nanobrachytherapy.

We describe the simple fabrication of poly({198Au}) radioactive gold-dendrimer composite nanodevices in distinct sizes (diameter between 10 nm and 29 nm) for targeted radiopharmaceutical dose delivery to tumors in vivo. Irradiation of aqueous solutions of 197Au containing poly(amidoamine) dendrimer tetrachloroaurate salts or {197Au0} gold-dendrimer nanocomposites in a nuclear reactor resulted in the formation of positively charged and soluble poly{198Au0} radioactive composite nanodevices (CNDs). A mouse melanoma tumor model was used to test whether the poly{198Au0} CNDs can deliver a therapeutic dose. A single intratumoral injection of poly{198Au0}(d=22nm) CNDs in phosphate-buffered saline delivering a dose of 74 muCi resulted after 8 days in a statistically significant 45% reduction in tumor volume, when compared with untreated groups and those injected with the "cold" nanodevice. No clinical toxicity was observed during the experiments. This study provides the first proof of principle that radioactive CNDs can deliver therapeutic doses to tumors.

In vivo biodistribution of dendrimers and dendrimer nanocomposites -- implications for cancer imaging and therapy.

Our results indicate that the surface chemistry, composition, and 3-D structure of nanoparticles are critical in determining their in vivo biodistribution, and therefore the efficacy of nanodevice imaging and therapies. We demonstrate that gold/dendrimer nanocomposites in vivo, present biodistribution characteristics different from PAMAM dendrimers in a B16 mouse tumor model system. We review important chemical and biologic uses of these nanodevices and discuss the potential of nanocomposite devices to greatly improve cancer imaging and therapy, in particular radiation therapy. We also discuss major issues confronting the use of nanoparticles in the near future, with consideration of toxicity analysis and whether biodegradable devices are needed or even desirable.