Lycopene coupled ‘trifoliate’ polyaniline nanofibers as multi-functional biomaterial

Abstract

Bio-conjugation seems to be an unparalleled avenue to tailor the shape-size-bioactivity accord of nanomaterials. In this backdrop, conjugation of tomato peel lycopene through the green chemistry tool of sonication, under statistically optimized parameters led to the morphological alteration of polyaniline (PAni) nanofiber from linear to biomimetic ‘runner’ morphology with trifoliate branching as observed under TEM. X-ray diffractogram was suggestive of alterations in the d-spacing and strain in the polymer backbone post lycopene binding. Post bio-conjugation, the semiconducting-behavior of the PAni nanofibers was retained although lycopene coupling resulted in a decrease in the former's conductivity. DMol3 was employed for the quantum molecular calculations of lycopene interacting with PAni (via non-covalent functionalization involving π–π stacking) and its solvation study. The contribution to HOMO came from the lycopene unit whereas the LUMO had contribution from the aromatic ring of PAni in the conjugated system. The bioactivity of the PAni nanofibers post bio-conjugation was attested by free radical scavenging and anti-lipid peroxidation of liver tissue homogenate. Epiflorescence microscopic imaging demonstrated the cytocompatibility with L929 normal cell line while the nuclear fragmentation and membrane blebbing of apoptotic HeLa cells vouched for the anticancer action of the conjugated system. Furthermore, the reported system exhibited a stimulatory effect on Cucumis sativus seed germination. Thus the study marshals in support of modulated morphology and desirable bio-action of nanoscaled biomaterials via bio-conjugation for advanced applications.