Although agrochemical practices can enhance agricultural
productivity,
their intensive application has resulted in the deterioration of ecosystems.
Therefore, it is necessary to develop more efficient and less toxic
methods against pests and infections while improving crop productivity.
Moving toward sustainable development, in this work, we originally
described the preparation of a composite (ZIF-8@HA) consisting of
the coating of zeolitic-like metal–organic framework (MOF)
ZIF-8 (based on Zn, an essential micronutrient in plants with antibacterial,
antifungal, and antifouling properties) with hydroxyapatite (HA) nanoparticles
(i.e., nanofertilizer). The interaction between the HA and ZIF-8 has
been characterized through a combination of techniques, such as microscopic
techniques, where the presence of a HA coating is demonstrated; or
by analysis of the surface charge with a dramatic change in the Z-potential
(from +18.7 ± 0.8 to −27.6 ± 0.7 mV for ZIF-8 and
ZIF-8@HA, respectively). Interestingly, the interaction of HA with
ZIF-8 delays the MOF degradation (from 4 h for pristine ZIF-8 to 168
h for HA-coated material), providing a slower and gradual release
of zinc. After a comprehensive characterization, the potential combined
fertilizer and bactericidal effect of ZIF-8@HA was investigated in
wheat (Triticum aestivum) seeds and Pseudomonas syringae (Ps). ZIF-8@HA
(7.3 ppm) demonstrated a great fertilizer effect, increasing shoot
(9.4 %) and root length (27.1 %) of wheat seeds after 11 days at 25
°C under dark conditions, improving the results obtained with
HA, ZIF-8, or ZnSO4 or even physically mixed constituents
(HA + ZIF-8). It was also effective in the growth inhibition (>80
% of growth inhibition) of Ps, a vegetal pathogen
causing considerable crop decline. Therefore, this work demonstrates
the potential of MOF@HA composites and paves the way as a promising
agrochemical with improved fertilizer and antibacterial properties.