However, this benefit comes at a cost: Nanomaterials can also cause unexpected changes in
cell signaling. For example, nanoparticles coated with intercellular adhesion molecule I (ICAM-I)
protein are internalized. This is an unusual finding because ICAM-I is not known to trigger endocytosis.
Yet, packingmultiple ICAM-I proteins onto a nanomaterial’s surface produces unexpected
uptake (7). Another study showed that 14-nm carbon nanoparticles interact with epidermal growth
receptors and β1-integrins on rat alveolar II epithelial cells and induce the activation of the Akt
signaling pathway, causing cell proliferation (8). An additional concern with nanoparticle-ligand
complexes is the potential denaturation of proteins when bound to the engineered surface. The
denaturation of a protein can affect binding to its receptor, increase nonspecific interactions or