Cellular Toxicity of Nanoparticles By: Amber Cardell

Nanoparticles m – very small 1-100nm in size Characteristics different from bulk material to nanoscale Changes chemical and/or physical properties lty/kerr.html

Nanoparticles- High Surface Area to Volume Ratio High surface tension Tendency to adhere and clump Increases solubility Drives diffusion Reduces melting temp Increases catalytic activity

Problems with Nanoparticles Readily pass through cell membranes Can penetrate RBCs Can penetrate nuclei Can pass the blood-brain barrier Increased mobility and reactivity Can overload phagocytes Can adhere to macromolecules, altering biochemical pathways

Regulation of Nanoparticles Not regulated by the EPA or FDA MSDS does not differentiate nanosize material Causes pollution as byproducts Commonly used in commercial products Cosmetics Protective coatings Toothpaste Stain resistant clothing Suntan lotion

Materials and Methods Cell culture Chinese Hamster Ovary Cells (CHO-K1) Transformed immortal cell line Sensitive to toxic agents Centrifuge cells Aseptic technique 70% ethanol- to sanitize all supplies UV light under hood to eliminate microbial contaminants in the work area

Materials and Methods Controlled environment Culture plates and flasks 5% CO 2, 95% air 37°C Liquid Media 90% Kaighn’s Modification  Essential nutrients for CHO cells 10% fetal bovine serum Penicillin-Streptomycin solution

Materials and Methods Trypsin Detaches cells Hanks Balanced Salt Solution Rinses cells pH indicator Solvent for nanoparticles PBS Rinses cells

Particles Used Latex Beads 800 nm- fine particulate matter Dyed blue 10 μl Talc particles 15 nm diameter Concentrations 0.1 mg/ml 1.0 mg/ml 10 mg/ml (protein content) Silica 7 nm diameter Concentrations 0.1 mg/ml 1.0 mg/ml 10 mg/ml (protein content)

Toxicity Assays Phase Contrast Microscope Trypan Blue Dead cells uptake dye Stored in nucleus Total Protein Content Bradford assay Spectrophotometer Standard curve Lower shows toxicity

CHO Cells- Control Normal Healthy Cell Cells treated with Media 24 hr exposure 100x 400x 1,000x

Experimental Results Cells treated with Latex Beads 10μl 24 hr exposure Beads inside cell Beads outside cell 100x 400x 1,000x

Experimental Results Cells treated with 1.0 mg/ml talc 24 hr exposure Dead cell 100x 400x 1,000x

Experimental Results Cells treated with 1.0 mg/ml Silica 24 hr exposure Dead Cell 100x 400x 1,000x

Cellular Toxicity

Total Cell Protein Content

Total Protein Content

Conclusions Nanoparticles were uptaken by the cells Cell mortality increased with exposure to nanoparticles Silica seemed to be the most toxic agent Further toxicity research is needed before continuing the use of nanoparticles in commercial products

Acknowledgements Dr. Jacqueline Jordan- CSU Rishit Patel and Samantha Stuckey- CSU Derek Truyen Pham- Emory