The study investigates the use of single-walled carbon nanotubes (SWNTs) as intracellular protein transporters. Various proteins, including streptavidin, protein A, bovine serum albumin, and cytochrome c, spontaneously bind to the sidewalls of acid-oxidized SWNTs through non-specific interactions. These proteins can be transported inside mammalian cells via the endocytosis pathway, where they are released from endosomes and enter the cytoplasm. The biological functionality of these protein-nanotube conjugates is demonstrated by their ability to induce apoptosis in cells, as evidenced by the release of cytochrome c and the subsequent activation of caspases. The research highlights the potential of SWNTs as molecular transporters for in-vitro and in-vivo protein delivery applications, with the need for further investigation into detailed uptake mechanisms, cargo release strategies, and long-term cytotoxicity effects.The study investigates the use of single-walled carbon nanotubes (SWNTs) as intracellular protein transporters. Various proteins, including streptavidin, protein A, bovine serum albumin, and cytochrome c, spontaneously bind to the sidewalls of acid-oxidized SWNTs through non-specific interactions. These proteins can be transported inside mammalian cells via the endocytosis pathway, where they are released from endosomes and enter the cytoplasm. The biological functionality of these protein-nanotube conjugates is demonstrated by their ability to induce apoptosis in cells, as evidenced by the release of cytochrome c and the subsequent activation of caspases. The research highlights the potential of SWNTs as molecular transporters for in-vitro and in-vivo protein delivery applications, with the need for further investigation into detailed uptake mechanisms, cargo release strategies, and long-term cytotoxicity effects.