Cellulose Nanocrystals are a Renewable and Biocompatible Nanocarrier of Agrochemicals Directly to Plant Cells

Abstract

More sustainable agricultural practices are critical to meeting humanity's food needs while minimizing adverse environmental impacts. Engineered nanomaterials used as nanocarriers promise to reduce the volume of agrochemicals required for crop production but concerns about nanocontamination of agricultural products necessitate the discovery of naturally occurring alternatives. Here, plant‐derived cellulose nanocrystals (CNC) as a “green” alternative to man‐made nanomaterials for the economical delivery of agrochemicals to plants are suggested. Using confocal microscopy and fluorescently labeled CNC, it is demonstrated that CNC can successfully penetrate the plant cell wall and enter cells without causing any negative effects on the overall plant phenotype, genome, and metabolome. The efficiency of CNC to deliver chemicals is demonstrated through in vitro tests involving CNC covalently conjugated with 2,4‐dichlorophenoxyacetic acid (2,4‐D). Plant cell culture experiments confirmed that CNC can be used as a 2,4‐D nanocarrier and reduces the volume of plant growth regulators needed to cultivate plant cells. This work creates a new platform for cyclical agricultural practices where CNC extracted from agricultural waste can be used for the direct delivery of agrochemicals to crops, thereby reducing the environmental burden created by both agricultural waste and excess herbicides.

Properties of APTES-Modified CNC Films

“…Quantifying the degree of substitution (DS) on CNCs is a known challenge due to the relatively low number of surface hydroxyl groups available for functionalization and the need to use multiple analytical methods, all of which have some experimental limitations . In this study, the DS was calculated based on the number of hydroxyl groups available on the CNCs' surfaces, and the weight percent of nitrogen was determined using ultimate analysis . The number of available hydroxyl groups on a CNC’s surface was determined based on the model predicted by Eyley and Thielemans using eq . N OH = n 1 + n 2 ρ N A L 1 L 2 c ( L 1 + L 2 d false( 110 false) + L 1 + L 2 d false( 1 1̅ 0 false) ) + 2 false( ρ N A L 3 d false( 110 false) d false( 1 1̅ 0 false) false) − 1 where L 1 , L 2 , and L 3 define the height, width, and length of the CNCs, respectively, d (110) and d (11̅0 ) are the horizontal and vertical unit cell dimensions of CNCs, respectively, n 1 and n 2 are the number of primary −OH groups facing (110) and (11̅0) planes in the unit cell, respectively, ρ is the density, c is the unit cell dimension, and N A stands for the Avogadro’s number.…”

“… 31 In this study, the DS was calculated based on the number of hydroxyl groups available on the CNCs' surfaces, and the weight percent of nitrogen was determined using ultimate analysis. 32 The number of available hydroxyl groups on a CNC’s surface was determined based on the model predicted by Eyley and Thielemans 31 using eq 1 . where L 1 , L 2 , and L 3 define the height, width, and length of the CNCs, respectively, d (110) and d (11̅0 ) are the horizontal and vertical unit cell dimensions of CNCs, respectively, n 1 and n 2 are the number of primary −OH groups facing (110) and (11̅0) planes in the unit cell, respectively, ρ is the density, c is the unit cell dimension, and N A stands for the Avogadro’s number.…”

Effects of NaOH Addition on Cellulose Nanocrystal Functionalization with 2,4-Dichlorophenoxyacetic Acid

“…Cellulose nanocrystals (CNCs) have been proven to be an effective nanocarrier of active biomolecules in agricultural and medical applications in part due to their unique properties such as high aspect ratio and needle-like shape, low toxicity to mammals and plants, and renewability (DeLoid et al, 2019; Salari et al, 2019; Vinzant et al, 2023). However, the commercial success of CNC nanocarriers will be dependent on the e ciency of chemical reactions and conjugation performed on a large scale.…”