Short communicationEvaluation of penetration of nanocarriers into red pepper leaf using confocal laser scanning microscopy

•Nanocarriers (negative and positive charge) were prepared by hot high pressure homogenization.•Encapsulation efficiency, payload and concentration of pesticide in the formulations were high.•Penetration of nanocarriers was illustrated by confocal laser scanning microscopy observation.•Both of negatively and positively charged nanocarriers quickly penetrated into red pepper leaf.•Negatively charged nanocarriers had a faster penetration than positively charged nanocarriers.

Penetration of nanocarriers into red pepper leaf was evaluated with the aim of identifying a novel way to enhance the efficacy of applied pesticides on the field. In addition, the effect of surface charge of the nanocarriers on penetration was also studied. Particularly, corn oil-nanoemulsions (NE) and chitosan coated NE (CH-NE) were successfully prepared with a high encapsulation efficiency, a high payload, a very small size, a small polydispersity index, and a high zeta potential. However, after being coated with chitosan, the zeta potential of NE changed from a negative charge to a positive charge. Penetration experiments were also carried out using a Franz diffusion cell followed by visualization using confocal laser scanning microscopy. The images of the vertical sections illustrated that penetration of nanocarriers (NE and CH-NE) into the red pepper leaf occurred very quickly. Nanocarriers fully penetrated the whole leaf after 60 min. Moreover, multi-depth images that paralleled the leaf surface (horizontal visualization) together with removal of plant-autofluorescent emissions and three-dimensional graphs describing the penetration of NE and CH-NE demonstrated that the negatively charged nanocarriers (NE) had a higher penetration rate compared to that of the positively charged nanocarriers (CH-NE).