Carbon nanotube biocompatibility in plants is determined by their surface chemistry

Background 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. Results Herein, we characterize the response of Arabidopsis thaliana to single walled carbon nanotube (SWNT) exposure with two different surface chemistries commonly used for biosensing and nucleic acid delivery: oligonucleotide adsorbed-pristine SWNTs, and polyethyleneimine-SWNTs loaded with plasmid DNA (PEI-SWNTs), both introduced by leaf infiltration. We observed that pristine SWNTs elicit a mild stress response almost undistinguishable from the infiltration process, indicating that these nanomaterials are well-tolerated by the plant. However, PEI-SWNTs induce a much larger transcriptional reprogramming that involves stress, immunity, and senescence responses. PEI-SWNT-induced transcriptional profile is very similar to that of mutant plants displaying a constitutive immune response or treated with stress-priming agrochemicals. We selected molecular markers from our transcriptomic analysis and identified PEI as the main cause of this adverse reaction. We show that PEI-SWNT response is concentration-dependent and, when persistent over time, leads to cell death. We probed a panel of PEI variant-functionalized SWNTs across two plant species and identified biocompatible SWNT surface functionalizations. Conclusions 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. Graphical Abstract

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 Arabidopsis thaliana transcriptional response to single walled carbon nanotubes (SWNTs) with two different surface chemistries commonly used for biosensing and nucleic acid delivery: oligonucleotide adsorbed-pristine SWNTs, and polyethyleneimine-SWNTs loaded with plasmid DNA (PEI-SWNTs), both introduced by leaf infiltration. We observed that SWNTs elicit a mild stress response almost undistinguishable from the infiltration process, indicating that these nanomaterials are well-tolerated by the plant. However, PEI-SWNTs induce a much larger transcriptional reprogramming that involves stress, immunity, and senescence responses. PEI-SWNT-induced transcriptional profile is very similar to that of mutant plants displaying a constitutive immune response or treated with stress-priming agrochemicals. We selected molecular markers from our transcriptomic analysis and identified PEI as the main cause of this reaction. We show that PEI-SWNT response is concentration-dependent and, when persistent over time, leads to cell death. We probed a panel of PEI variant-functionalized SWNTs across two plant species and identified biocompatible SWNT surface functionalizations. Our results highlight the importance of nanoparticle surface chemistry on their biocompatibility and will facilitate the use of functionalized nanomaterials for agricultural improvement.

Biofunctional Surfaces for Smart Entrapment of Polysomes

Protein synthesis is a central process in all cells, crucial for cell development and maintenance. Translational dysregulation, in fact, is associated with cancer or neurodegenerative diseases. Active protein synthesis occurs on a supramolecular complex, named polyribosome or polysome, formed by a mRNA associated with multiple ribosomes. Polysomes therefore can be considered as a privileged molecular platform to obtain information about the physiological or pathological state in cells. The classical methods for purifying the mRNAs associated with polysomes mainly rely on ultracentrifugation in sucrose gradient followed by standard RNA extraction. This method present several drawbacks, among all it is a time-consuming procedure, which requires a fairly large amounts of starting material. New methods offering an efficient, rapid and user-friendly alternative to standard methods are therefore highly desirable. Here, a panel of surfaces and surface functionalizations were screened for their ability to entrap polysomes with the ultimate aim to set up smart biofunctional surfaces for the purification of nonlabelled polysomes and their associated mRNAs. As a proof-of-concept, prepurified ribosomes and polysomes were incubated on multiple functional surfaces and characterized by atomic force microscopy to assess number and morphology of entrapped polysomes. Surfaces able to efficiently capture polysomes were then included in a microdevice with promising results, opening the future perspective of developing protocols and devices based on biofunctional surfaces.

Assessing the protective effects of different surface coatings on NaYF4:Yb3+, Er3+ upconverting nanoparticles in buffer and DMEM

We studied the dissolution behavior of β NaYF4:Yb(20%), Er(2%) UCNP of two different sizes in biologically relevant media i.e., water (neutral pH), phosphate buffered saline (PBS), and Dulbecco’s modified Eagle medium (DMEM) at different temperatures and particle concentrations. Special emphasis was dedicated to assess the influence of different surface functionalizations, particularly the potential of mesoporous and microporous silica shells of different thicknesses for UCNP stabilization and protection. Dissolution was quantified electrochemically using a fluoride ion selective electrode (ISE) and by inductively coupled plasma optical emission spectrometry (ICP OES). In addition, dissolution was monitored fluorometrically. These experiments revealed that a thick microporous silica shell drastically decreased dissolution. Our results also underline the critical influence of the chemical composition of the aqueous environment on UCNP dissolution. In DMEM, we observed the formation of a layer of adsorbed molecules on the UCNP surface that protected the UCNP from dissolution and enhanced their fluorescence. Examination of this layer by X-ray photoelectron spectroscopy (XPS) and mass spectrometry (MS) suggested that mainly phenylalanine, lysine, and glucose are adsorbed from DMEM. These findings should be considered in the future for cellular toxicity studies with UCNP and other nanoparticles and the design of new biocompatible surface coatings.

GALLIUM NANOPARTICLES AS DELIVERY SYSTEM AGAINST INFECTIOUS DISEASES AND CANCER

As viruses, microbes, other pathogenic microorganisms and toxic agents are responsible for global broad spectrum diseases including cancer and malignant hypercalcemia, resulting significant mortality and morbidity, nanobiotechnology-based nanoparticles are being emerged as new nanomedicines for their biological applications owing to their unique shape, size and ease surface functionalizations. To overcome drug resistance and toxicity, gallium (Ga(III)) metal nanoparticles (GaNPs) have attracted attention for their requirements for prolonged treatments, especially, against human immunodeficiency virus, mycobacterium, hypercalcemia and cancer. These nanoparticles remain stable for the longer periods owing to the formation of native and passivating 2-3 nm oxide layer. Therefore, it is needed to encapsulate the NPs with bioactive compounds within vesicular system associated ligand-binding for specific delivery to target-sites for getting better efficacies. This review depicts especially the role of GaNPs as delivery system against infectious diseases and cancer.

Use of Silica Based Materials as Modulators of the Lipase Catalyzed Hydrolysis of Fats under Simulated Duodenal Conditions

The effect of silica materials and their functionalization in the lipase catalyzed fat hydrolysis has been scarcely studied. Fifteen silica materials were prepared and their effect on the fat hydrolysis was measured, under simulated duodenal conditions, using the pH-stat method. The materials are composed of the combination of three supports (Stöber massive silica nanoparticles, Stöber mesoporous nanoparticles and UVM-7) and four surface functionalizations (methyl, trimethyl, propyl and octyl). In addition, the non-functionalized materials were tested. The functional groups were selected to offer a hydrophobic character to the material improving the interaction with the fat globules and the lipase. The materials are able to modulate the lipase activity and their effect depending on the support topology and the organic covering, being able to increase or reduce the fat hydrolysis. Depending of the material, relative fat hydrolysis rates of 75 to 140% in comparison with absence of the material were obtained. The results were analyzed by Partial Least Square Regression and suggest that the alkyl modified mesopores are able to improve the fat hydrolysis, by contrast the non-porous nanoparticles and the textural pores tend to induce inhibition. The effects are more pronounced for materials containing long alkyl chains and/or in absence of taurodeoxycholate.

Tailoring nanoparticle-biofilm interactions to increase efficacy of antimicrobial agents against Staphylococcus aureus

<p>Considering the timeline required for the development of novel antimicrobial drugs, increased attention should be given to repurposing existing drugs and improving their antimicrobial efficacy, particularly for chronic infections associated with biofilms. Methicillin-susceptible Staphylococcus aureus (MSSA) and methicillin-resistant S. aureus (MRSA) are common causes of biofilm-associated infections however each species has a distinct biofilm phenotype resulting in different biofilm matrix characteristics.. Nanoparticles (NPs) have the potential to significantly enhance the delivery of antimicrobial agents into biofilms, however the physicochemical properties which influence these interactions between NPs and the biofilm are not fully understood. The influence of NP surface chemistry on interactions with MRSA and MSSA biofilms was explored in this study. Mesoporous silica nanoparticles (MSNs) with different surface functionalizations (bare-B, amine-D, carboxyl-C, aromatic-A) were synthesised. Following interaction studies, MSNs were loaded with vancomycin (VAN) to observe biofilm eradication. The two negatively charged MSNs (MSN-B and MSN-C) showed a higher VAN loading in comparison to the positively charged MSNs (MSN-D and MSN-A). Cellular binding with MSN suspensions (0.25 mg mL<sup>-1</sup>) correlated with reduced viability of both MSSA and MRSA biofilm cells. MSNs were shown to be efficient carriers of vancomycin while also displaying significantly improved efficiency compared to free VAN. This allowed the administration of low MSNs concentrations, while maintaining a high local concentration of the antibiotic surrounding the bacterial cells, indicating a promising novel therapeutic approach for S. aureus biofilm infections.</p>