Achieving the co-assembly of more than one component represents an important challenge in the drive to create functional self-assembled nanomaterials. Multicomponent nanomaterials comprised of several discrete, spatially sorted domains of components with high degrees of internal order are particularly important for applications such as optoelectronics. In this work, single-walled carbon nanotubes (SWNTs) were threaded through the inner channel of nanotubes formed by the bolaamphiphilic self-assembly of a naphthalenediimide-lysine (NDI-Bola) monomer. The self-assembly process was driven by electrostatic interactions, as indicated by ζ -potential measurements, and cation–π interactions between the surface of the SWNT and the positively charged, NDI-Bola nanotube interior. To increase the threading efficiency, the NDI-Bola nanotubes were fragmented into shortened segments with lengths of <100 nm via sonication-induced shear, prior to co-assembly with the SWNTs. The threading process created an initial composite nanostructure in which the SWNTs were threaded by multiple, shortened segments of the NDI-Bola nanotube that progressively re-elongated along the SWNT surface into a continuous radial coating around the SWNT. The resultant composite structure displayed NDI-Bola wall thicknesses twice that of the parent nanotube, reflecting a bilayer wall structure, as compared to the monolayer structure of the parent NDI-Bola nanotube. As a final, co-axial outer layer, poly( p -phenyleneethynylene) (PPE-SO 3 Na, M W = 5.76 × 10 4 , PDI – 1.11) was wrapped around the SWNT/NDI-Bola composite resulting in a three-component (SWNT/NDI-Bola/PPE-SO 3 Na) composite nanostructure.
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Carbon nanotube biocompatibility in plants is determined by their surface chemistry
Agriculture faces significant global challenges including climate change and an increasing food demand due to a growing population. Addressing these challenges will require the adoption of transformative innovations into biotechnology practice, such as nanotechnology. Recently, nanomaterials have emerged as unmatched tools for their use as biosensors, or as biomolecule delivery vehicles. Despite their increasingly prolific use, plant-nanomaterial interactions remain poorly characterized, drawing into question the breadth of their utility and their broader environmental compatibility.
Herein, we characterize the response of
While SWNTs themselves are well tolerated by plants, SWNTs surface-functionalized with positively charged polymers become toxic and produce cell death. We use molecular markers to identify more biocompatible SWNT formulations. Our results highlight the importance of nanoparticle surface chemistry on their biocompatibility and will facilitate the use of functionalized nanomaterials for agricultural improvement.
- NSF-PAR ID:
- 10362958
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Journal of Nanobiotechnology
- Volume:
- 19
- Issue:
- 1
- ISSN:
- 1477-3155
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Current practices for delivering agrochemicals are inefficient, with only a fraction reaching the intended targets in plants. The surfaces of nanocarriers are functionalized with sucrose, enabling rapid and efficient foliar delivery into the plant phloem, a vascular tissue that transports sugars, signaling molecules, and agrochemicals through the whole plant. The chemical affinity of sucrose molecules to sugar membrane transporters on the phloem cells enhances the uptake of sucrose‐coated quantum dots (sucQD) and biocompatible carbon dots with β‐cyclodextrin molecular baskets (suc‐β‐CD) that can carry a wide range of agrochemicals. The QD and CD fluorescence emission properties allowed detection and monitoring of rapid translocation (<40 min) in the vasculature of wheat leaves by confocal and epifluorescence microscopy. The suc‐β‐CDs more than doubled the delivery of chemical cargoes into the leaf vascular tissue. Inductively coupled plasma mass spectrometry (ICP‐MS) analysis showed that the fraction of sucQDs loaded into the phloem and transported to roots is over 6.8 times higher than unmodified QDs. The sucrose coating of nanoparticles approach enables unprecedented targeted delivery to roots with ≈70% of phloem‐loaded nanoparticles delivered to roots. The use of plant biorecognition molecules mediated delivery provides an efficient approach for guiding nanocarriers containing agrochemicals to the plant vasculature and whole plants.
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Societal Impact Statement Plant genomes hold the key to understanding the evolutionary history of plants, a lineage that goes back nearly a billion years and contains nearly half a million living species. This history—or phylogeny—is both a record of life now past and a powerful predictive tool for both basic and applied plant science. Coupled phylogenetic and genomic studies can reveal the processes by which new species arise and go extinct, and phylogenies can guide our efforts to improve crop plants, discover new medicines, and develop effective conservation strategies.
Summary Plant genomes exhibit spectacular diversity in size, composition, and complexity, and although we suspect that this diversity is related to the equally spectacular diversity of plant form and function, this link is still poorly understood. Plant genomes carry signatures of evolutionary history, whole‐genome duplication, population processes, and more, and we are just learning how to read this historical information from appropriate genetic markers. But plant genomes are not merely chroniclers of past evolutionary change: they are dynamic, evolving entities in their own right, driving changes in plant chemistry, morphology, ecology, and more. Here, we describe how plant genomes have been harnessed for studies of plant phylogeny and diversification, with examples spanning all green plants, a clade of nearly half a million species spanning nearly a billion years of evolutionary time. Then focusing on angiosperms, we suggest how the process of whole‐genome duplication (polyploidy) has driven, and continues to drive, major innovations in morphology, stress response, and more. Together, these perspectives will begin to reveal how genomic change can lead to novelty and diversity at the organismal level. Finally, we review how little we actually know about plant genomes, given that assembled genome sequences exist for fewer than 1% of all plant species—a major shortcoming as we seek to meet societal challenges of food security, the need for new medicines, and conservation of species in response to climate change.
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Abstract The growth, survival, and productivity of plants are constantly challenged by diverse abiotic stresses. When plants are exposed to stress for the first time, they can capture molecular information and store it as a form of memory, which enables them to competently and rapidly respond to subsequent stress(es). This process is referred to as a priming-induced or acquired stress response. In this review, we discuss how (i) the storage and retrieval of the information from stress memory modulates plant physiological, cellular, and molecular processes in response to subsequent stress(es), (ii) the intensity, recurrence, and duration of priming stimuli influences the outcomes of the stress response, and (iii) the varying responses at different plant developmental stages. We highlight current understanding of the distinct and common molecular processes manifested at the epigenetic, (post-)transcriptional, and post-translational levels mediated by stress-associated molecules and metabolites, including phytohormones. We conclude by emphasizing how unravelling the molecular circuitry underlying diverse priming-stimuli-induced stress responses could propel the use of priming as a management practice for crop plants. This practice, in combination with precision agriculture, could aid in increasing yield quantity and quality to meet the rapidly rising demand for food.
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Abstract DNA polymer‐wrapped single‐walled carbon nanotubes (SWNTs) finds a widespread use in a variety of nanotechnology applications. Molecular dynamics (MD) simulations and experiments are used to explore the relationship between structural conformation, binding affinity, and kinetic stability for short single‐stranded oligonucleotides adsorbed on SWNTs. The conformation of 36 oligonucleotide sequences on (9,4) SWNT is computationally screened, where the polymer lengths are selected so the polymers can, to a first approximation, wrap once around the SWNT circumference. The identified conformations can be broadly classified into “rings” and “non‐rings.” Then, 2D conformational free energy landscapes for selected sequences are obtained by temperature replica exchange calculations. Propensity for “ring” conformations are driven primarily by sequence chemistry and the ability of the polymer to form compact structures. However, ring‐formation probability is found to be uncorrelated with free energy of oligonucleotide binding to SWNTs (∆
G bind). Conformational analyses of oligonucleotides, computed free energy of binding of oligonucleotides to SWNTs, and experimentally determined kinetic stability measurements show that ∆G bindis the primary correlate for kinetic stability. The probability of the sequence to adopt a compact, ring‐like conformation is shown to play a secondary role that still contributes measurably and positively to kinetic stability.
