A non-classical route of efficient plant uptake verified with fluorescent nanoparticles and root adhesion forces investigated using AFM

Classical plant uptake is limited to hydrophilic or water-dispersible material. Therefore, in order to test the uptake behaviour of hydrophobic particles, here, we tested the fate of hydrophobic particles (oleylamine coated Cu₂ₓSe NPs (CS@OA)) in comparison to hydrophilic particles (chitosan-coated CU₂ₓSe NPs (CS@CH)) by treatment on the plant roots. Surprisingly, hydrophobic CS@OA NPs have been found to be ~1.3 times more efficient than hydrophilic CS@CH NPs in tomato plant root penetration. An atomic force microscopy (AFM) adhesion force experiment confirms that hydrophobic NPs experience non-spontaneous yet energetically favorable root trapping and penetration. Further, a relative difference in the hydrophobic vs. hydrophilic NPs movement from roots to shoots has been observed and found related to the change in protein corona as identified by two dimensional-polyacrylamide gel electrophoresis (2D-PAGE) analysis. Finally, the toxicity assays at the give concentration showed that Cu₂ₓSe NPs lead to non-significant toxicity as compared to control. This technology may find an advantage in fertilizer application.

Sandeep Sharma, Mohd. Muddassir, Saraladevi Muthusamy, Pardeep Kumar Vaishnav, Manish Singh, Deepak Sharma, Selvaraju Kanagarajan, Vijayakumar Shanmugam