Potential targetability of multi-walled carbon nanotube loaded with silver nanoparticles photosynthesized from Ocimum tenuiflorum (tulsi extract) in fertility diagnosis

Abstract

Nanocarrier mediated targeted delivery and biosensing in reproductive health care is a major exploratory domain. This work demonstrates the loading of silver nanoparticle (AgNP) inside the multiwalled carbon nanotube (MWCNT) and their targetability to the intracellular part of the sperm cell for its further application in biosensing based infertility diagnosis. Ocimum tenuiflorum (tulsi extract) mediated photosynthesized AgNP exhibited spherical shape, 5–40 nm size and surface plasmonic resonance at 430 nm. After loading of freshly prepared AgNP into emulsified MWCNT, the loading was confirmed with spectroscopic and microscopic methods. FTIR analysis displayed significant shifting at 3450 cm−1 (–OH stretching) and 1615 cm−1 (CNT back bone) which validated the binding of AgNP with MWCNT and interestingly heat flow analysis revealed that Ag loaded MWCNT has greater stability than AgNP. Moreover, AFM based surface profile height analysis clearly showed the loading of AgNP inside MWCNT as surface height of MWCNT increased from 22 to 32 nm, which in turn confirmed the encapsulation of 10 nm size of AgNP inside the tube. Furthermore, surface enhanced Raman spectroscopy (SERS) confirmed the homogeneous loading as there were no changes in D/G ratio. SERS analysis for the interaction of AgNP loaded MWCNT with freshly collected healthy, motile human spermatozoa showed a significant Raman shift at 800–780 cm−1 (NH2+ twist) and 1050–1060 cm−1 (vas PO3−) for change in DNA packaging process and its stabilizing protein polyamine respectively. Finally, DNA fragmentation and morphological examination confirmed the binding and targetability of AgNP to the sperm nucleus. Improved targeting efficiency and biosenssing ability make AgNP-MWCNT composite suitable in fertility diagnosis.