Specific types of glycosphingolipid (GSL), which are chemically detectable in normal cells, are more highly expressed in tumors. The high level of expression on the surfaces of tumor cells causes an antibody response to these GSLs, which can therefore be described as tumor-associated antigens. Some of these GSLs have been shown to be adhesion molecules involved in tumor cell metastasis, and to be modulators of signal transduction controlling tumor cell growth and motility. Tumor-associated GSL antigens have been used in the development of antitumor vaccines. GSLs and sphingolipids involved in adhesion and signaling are therefore targets for cancer therapy.

Recent research has highlighted a growing focus on stimuli-responsive surfactant wormlike micelles (WLMs), particularly those with switchability. Here we report CO2-switchable WLMs based on the commercial anionic surfactant sodium dodecyl sulfate (SDS) and N,N,N',N'-tetramethyl-1,3-propanediamine (TMPDA) mixed in a mole ratio of 2:1. When CO2 is bubbled into an aqueous mixture of these reactants, the TMPDA molecules are protonated to form quaternary ammonium species, two of which in the same protonated TMPDA molecule "bridge" two SDS molecules by noncovalent electrostatic attraction, behaving like a pseudogemini surfactant and forming viscoelastic WLMs as verified by cryo-TEM. Upon removal of CO2, the quaternized spacers are deprotonated back to tertiary amines, dissociating the pseudogeminis back to conventional SDS molecules that form low-viscosity spherical micelles. Such a reversible sphere-to-worm transition could be repeated several cycles without a loss of response to CO2.

A wormlike micellar system that undergoes a fully reversible, repeatable "sol-gel" transition upon alternative treatment with CO2 and N2 has been developed based on a C18-tailed polyamine surfactant.