Green Nanopesticide: pH-Responsive Eco-Friendly Pillar[5]arene-Modified Selenium Nanoparticles for Smart Delivery of Carbendazim to Suppress Sclerotinia Diseases

Controlled-release delivery systems have been widely used to improve the efficacy and bioavailability of pesticides and minimize environmental risks. Herein, a fungicide carbendazim (CBZ)-loaded, a kind of nanovalve including trimethylammoniumpillar[5]­arene (AP5), and methyl orange (MO)-functionalized mesoporous selenium (MSe) nanopesticides (CBZ@AP5/MSe⊃MO) were prepared. The nanovalve endowed CBZ@AP5/MSe⊃MO with a pH-responsive property, so the CBZ@AP5/MSe⊃MO can respond to the microenvironment of the pathogen Sclerotinia sclerotiorum (S. sclerotiorum). First, MO was shed due to protonation, and AP5-functionalized MSe gradually dissolved in an acid environment. Finally, CBZ was released rapidly. It is reported that AP5 and MO as the host and guest functionalized mesoporous selenium (MSe) have never been applied to agriculture. In vitro release experiments showed that the cumulative release rate of CBZ at pH 4.5 was 1.74 times higher than that in a neutral environment. In addition, we found that the contact angle of the CBZ@AP5/MSe⊃MO in maize and rape leaves was effectively decreased, which could retain more in the leaves after washout. It can also decrease the dry biomass and the reducing sugar of S.sclerotiorum. The CBZ@AP5/MSe⊃MO holds a good safety profile for plants, animal cells, and the environment owing to the targeted release properties. These results suggest that CBZ@AP5/MSe⊃MO is an environmentally friendly and effective drug-loaded system against S. sclerotiorum. It provides a new strategy for the design and development of nanopesticides and the control of S. sclerotiorum.