The structure of a C70 fullerene molecule resembles an elongated C60 molecule. It has 10 additional carbon atoms that form five extra hexagons as show in red in this illustration. ref
Fullerene vendors will specify a purity percentage for their C60 products. A purity of 99.9% means there is 99.9 % C60, ~ 0.1 % C70 and possibly trace amounts of higher fullerenes.
Published research on the biological affects of C70 is limited to a handful of papers. Information to date does not suggest any dileterious affects. Results suggest that C70 will primarily localize to the ER (endoplasmic reticulum) and to a lessor extent to the mitochondria and lysosomes in cells. In the ER, the C70 will act to reduce ROS (reactive oxygen species).
Key summary points from the papers listed below …
Antioxidant Effect of C60 and C70 Fullerene in the Autoxidation of Ethyl Oleate
It was found that C60 is oxidized to fullerene oxide by scavenging the peroxy radical formed in the allylic position to the double bond of ethyl oleate. The scavenging rate constant of C60 has been measured and found considerably higher than that of C70.
In ethyl palmitate, a saturated fatty acid ester which does not undergo autoxidation, C60, is stable and is not oxidized even at 70°C for several hours.
C70-Carboxyfullerenes as Efficient Antioxidants to Protect Cells against Oxidative-Induced Stress
C70-carboxyfullerenes (dimalonic acid C70 fullerene (DF70) and trimalonic acid C70 fullerene (TF70)) exhibit an obviously protective effect against oxidative stress on C2C12 cells.
Quadri-malonic acid C60 fullerene (QF60)) show a protective effect at relatively higher concentration.
Further study reveals that DF70 and TF70 could enter into cells and mainly localize into the lysosome, which possibly involves the protective mechanism by stabilizing lysosome.
A lysosome is a membrane-bound organelle found in many animal cells and most plant cells. They are spherical vesicles that contain hydrolytic enzymes that can break down many kinds of biomolecules. These organelle are responsible for the digestion of macromolecules, old cell parts and microorganisms.
Structural effect and mechanism of C70-carboxyfullerenes as efficient sensitizers against cancer cells
Malonic acid modified C(70) fullerenes are more efficient than their C(60) counterparts as photosensitizers.
Death occurs via necrosis accompanied by membrane blebbing, which is a unique phenomenon for photosensitizer-induced cell death.
Uptake and distribution of fullerenes in human mast cells
Fullerenes (C70) that have previously been shown to be potent inhibitors of mast cell (MC)-mediated allergic inflammation.
We show C70-TR are non-specifically endocytosed into MC where they are shuttled throughout the cytoplasm, lysosomes, mitochondria, and into endoplasmic reticulum at different times.
These studies show MC endocytose fullerenes where they are shuttled to organelles involved with calcium and reactive oxygen species (ROS) production which may explain their efficacy as cellular inhibitors.
The cytoplasm is all of the material within a cell, enclosed by the cell membrane, except for the cell nucleus.
The functions of the endoplasmic reticulum can be summarized as the synthesis and export of proteins and membrane lipids, but varies between ER and cell type and cell function.