pH responsive NKMOF-based platform for targeted delivery of azoxystrobin with enhanced fungicidal efficacy and biosafety

Abstract

In this study, using a facile one-pot approach, we constructed a series of multifunctional and tunable pesticide formulation based on NKMOF-101-M (M = Mg, Mn, Zn, Co, or Ni) for azoxystrobin (AZOX), aiming to efficiently control gray mold disease. The physicochemical properties of AZOX@NKMOF-101-M, including particle size, zeta potential, release profile, and drug adhesion, were systematically characterized. The pesticide loading capacity and encapsulation efficiency reached up to 0.14 mg/mg and 90 %, respectively. Release studies demonstrated a pH-responsive behavior, attributed to the presence of weakly acidic groups in NKMOF-101-M. In vitro antifungal activity assays revealed that the efficacy of AZOX@NKMOF-101-M (M = Mg, Mn, Zn, Ni) was comparable to that of free AZOX. Notably, AZOX@NKMOF-101-Co exhibited significantly enhanced antifungal activity, which might be attributed to the synergistic interaction between AZOX and cobalt ions. In pot trials, AZOX@NKMOF-101-Co demonstrated approximately 80 % efficacy in controlling Botrytis cinerea infection. Fluorescence tracking of NKMOF-101-Co and biosafety experiments showed that NKMOF-101-Co could be absorbed by plant leaves and transported to various parts of tomato seedlings and that AZOX@NKMOF-101-Co was relatively safe for silkworms, zebrafish, and 293 T cells. Furthermore, these formulations could promoted seed germination and tomato growth, thereby functioning as effective fertilizers to enhance crop yield. This work highlights the potential of NKMOF-101-M as a multifunctional platform for the development of novel controlled-release pesticide formulations, offering a promising approach for sustainable agricultural practices.

Keywords: Azoxystrobin; Controlled-release; Metal-organic frameworks; Pesticide formulation; Synergistic antifungal.