Carbon Nanotubes as Intracellular Protein Transporters:  Generality and Biological Functionality

Abstract

Various proteins adsorb spontaneously on the sidewalls of acid-oxidized single-walled carbon nanotubes. This simple nonspecific binding scheme can be used to afford noncovalent protein-nanotube conjugates. The proteins are found to be readily transported inside various mammalian cells with nanotubes acting as the transporter via the endocytosis pathway. Once released from the endosomes, the internalized protein-nanotube conjugates can enter into the cytoplasm of cells and perform biological functions, evidenced by apoptosis induction by transported cytochrome c. Carbon nanotubes represent a new class of molecular transporters potentially useful for future in vitro and in vivo protein delivery applications.

Exploring the diameter and surface dependent conformational changes in carbon nanotube-protein corona and the related cytotoxicity

“…8, at pH 7.4 BSA molecules bear negative charge surface with potential of about −6.86 mV while −45.9, −34.8, and −27.0 mV for <10, 10-20 and 20-40 nm CNTs, respectively. Based on the fact that carboxylized CNTs interact with proteins through mainly electrostatic forces [23,24], it is assumed that the hydrophobic cavity of BSA, which is positive-charged at pH 7.4, is the main site to interact with the negative-charged CNTs. Trp-212, which originally buried in the hydrophobic cavity of BSA, has high possibility of coming into contact with CNTs, causing synchronous fluorescence spectra shifts at = 60 nm.…”

Folate and iron difunctionalized multiwall carbon nanotubes as dual-targeted drug nanocarrier to cancer cells

“…In the past 10 years, a variety of f-CNTs including oxidized, aminated, surfactant-assisted dispersed, polymer-assisted dispersed, and bio-molecular modified CNTs have been discovered [8] and utilized as the effective bio-molecular carriers to deliver peptides, proteins, nucleic acids and small molecular drugs into cellular systems. For instance, Kam et al have demonstrated the intracellular transportation of DNA [9], siR-NA [10], and proteins [11] using functionalized single-walled carbon nanotubes (f-SWCNTs) as non-targeted drug carriers. Pantarotto et al explored the delivery of bioactive peptides of K(FITC)QRMHLRQYELLC into 3T3 cells [12], methotrexate into Jurkat cells [13] and plasmid DNA into HeLa cells [14], using f-CNTs as non-targeted drug carriers.…”

Carbon Nanotube‐based Vectors for Delivering Immunotherapeutics and Drugs

“…Low toxicity was not only a characteristic of SWNTs functionalized with peptides. Both f -SWNTs and f -MWNTs, regardless of cell subtypes, are nontoxic on their own [90,220]. HeLa cells, incubated for several hours with about 1 mg mL À1 of CNTs mixed with plasmid DNA in different charge ratios, did not demonstrate signs of apoptosis [191].…”

“…However, only a few examples of delivery of therapeutic agents using CNTs are currently reported in the literature. Dai and coworkers have shown the potential of CNTs to transport proteins into the cells [90]. Single-walled CNTs were shortened to a length between 20 and 100 nm using strong acid conditions.…”