Polyethylene Glycol Surface Research Articles

Vortex Nanodiscs Functionalization to Overcome Macrophage Recognition for Efficient Theragnosis Applications

Biological barriers prevent nanotherapeutics successful accumulation at target cells, limiting diagnosis and treatment responses. Magnetic nanodiscs with a spin‐vortex ground state have shown great promise for magnetomechanical cancer cells annihilation and for neuronal stimulation, requiring very low concentrations for an effective result. However, the biological barriers that these particles encounter upon intravenous administration remain a challenge. Herein, the synthesis of biocompatible multilayered Au/Fe/Au nanodiscs with a spin‐vortex ground state and their inert surface modification is reported. Two different surface modifications with two distinct polyethylene glycol (PEG) molecules are performed, which successfully reduce macrophage uptake, while maintaining the nanodiscs’ biocompatibility. By effectively preventing nanodisc uptake, innovative design features can be rationally incorporated to create a new generation of specific nanotherapeutics by modifying the PEG surface with specific targeting molecules.

Degree of PEGylatation of Lumbricus terrestris Hemoglobin Improves Microcirculatory Blood Flow but Increases the Rate of Auto-Oxidation.

The demand for red blood cells (RBCs) is on the rise due to the increasing diagnosis of chronic diseases such as sickle cell anemia, malaria, and thalassemia. Despite many commercial attempts, there are no U.S. FDA-approved artificial RBCs for use in humans. Existing RBC substitutes have employed various strategies to transport oxygen, extend the circulation time, and reduce organ toxicity, but none have replicated the natural protective mechanisms of RBCs, which prevent hemoglobin (Hb) dimerization and heme iron oxidation. Lumbricus terrestris (earthworm) erythrocruorin (LtEc) is a naturally occurring extracellular hemoglobin (Hb) with promising attributes: large molecular diameter (30 nm), high molecular weight (3.6 MDa), low auto-oxidation rate, and limited nitric oxide-scavenging properties. These characteristics make LtEc an ideal candidate as an RBC substitute. However, LtEc has a significant drawback, its short circulatory half-life. To address this issue, we explored thiol-mediated surface PEGylation of LtEc (PEG-LtEc) at varying polyethylene glycol (PEG) surface coverages. Increasing PEG surface coverage beyond 40% destabilizes LtEc into smaller subunits that are 1/12th the size of LtEc. Therefore, we evaluated two PEG surface coverage options: PEG-LtEc-0.2 (20% PEGylation) and PEG-LtEc-1.0 (100% PEGylation). We conducted experiments using golden Syrian hamsters with dorsal window chambers and catheters to assess the efficacy of these solutions. We measured microvascular parameters, organ function, cerebral blood flow, circulation time, mean arterial pressure, heart rate, and blood gases and performed histology to screen for toxicity. Our findings indicate that both PEG-LtEc molecules offer significant benefits in restoring microvascular parameters, organ function, cerebral blood flow, and circulation time compared to LtEc alone. Notably, PEG-LtEc-1.0 showed superior microvascular perfusion, although it exhibited a higher rate of auto-oxidation compared to PEG-LtEc-0.2. These results underscore the advantages of PEGylation in terms of tissue perfusion and organ health while highlighting its limitations.

Enhancing camptothecin loading and release control through physical surface modification of organosilica nanoparticles with polyethylene glycol

The surface modification of nanoparticles holds the potential to enhance the loading capacity of drug molecules and regulate their release, making it possible to exploit the differences between tumor and normal cells. To this end, the surfaces of tetrasulfide-based phenylene-containing biodegradable periodic mesoporous organosilica (BPMO) nanoparticles (designated P4S) are modified herein with a hydrophilic and biocompatible polyethylene glycol (PEG) polymer. The PEG coating is optimized by adjusting the PEG concentration during synthesis, thus resulting in a significant increase in the nanoparticle stability. Furthermore, PEG modification enhances the nanoparticles' camptothecin (CPT) loading capacity. Drug release assessments under physical and acidic pH conditions demonstrate the pH-responsive properties of the P4S nanoparticles upon PEG functionalization, which results in increased drug release at low pH, along with enhanced cellular uptake potential. Notably, the cytotoxicity of CPT against HepG2 cancer cells is significantly improved when loaded into the P4S-PEG nanoparticles. These findings reveal the efficacy of PEG surface modification of the drug-delivery material in augmenting the activity of CPT, with promising prospects for clinical applications.

Improved Imaging Surface for Quantitative Single-Molecule Microscopy.

Preventing nonspecific binding is essential for sensitive surface-based quantitative single-molecule microscopy. Here we report a much-simplified RainX-F127 (RF-127) surface with improved passivation. This surface achieves up to 100-fold less nonspecific binding from protein aggregates compared to commonly used polyethylene glycol (PEG) surfaces. The method is compatible with common single-molecule techniques including single-molecule pull-down (SiMPull), super-resolution imaging, antibody-binding screening and single exosome visualization. This method is also able to specifically detect alpha-synuclein (α-syn) and tau aggregates from a wide range of biofluids including human serum, brain extracts, cerebrospinal fluid (CSF) and saliva. The simplicity of this method further allows the functionalization of microplates for robot-assisted high-throughput single-molecule experiments. Overall, this simple but improved surface offers a versatile platform for quantitative single-molecule microscopy without the need for specialized equipment or personnel.

Relationship between the polyurea underlayer structure and PEG surface coverage

Increasing the surface coverage of antifouling materials is essential to enhance the performance of antifouling coatings. In this study, polyurea thin-film underlayers were fabricated by co-depositing difunctional isocyanates with difunctional or trifunctional amines. The relationships among the underlayer structure, terminal group density before polyethylene glycol (PEG) termination, and PEG surface coverage were investigated. The results showed that employing trifunctional amines in the underlayer led to increased terminal group density before PEG termination. Moreover, the reduced hydrogen-bonding capability between the polyurea molecules contributes to enhanced PEG surface coverage.

Study on the stability and targeting of AuNPs based on PEG and pepducin surface modification

Gold nanoparticles (AuNPs) have garnered significant attention for their potential applications in cancer therapy. This study developed a novel formulation of AuNPs, named AuX2R, utilizing surface modification techniques to enhance biocompatibility and targeting capabilities for cancer treatment. The innovation of AuX2R lies in its simultaneous surface modification with polyethylene glycol (PEG) and lipidized peptides (pepducin), aimed at improving stability and cancer cell specificity. The study compared the stability of three different formulations of AuNPs in various solutions, indicating that PEGylation significantly increased nanoparticle stability, while the incorporation of pepducin enhanced their internalization and targeting towards cancer cells. This research not only provided a detailed analysis of the physicochemical properties and stability of the novel AuNPs but also investigated their internalization in prostate cancer cells, presenting new strategies for cancer therapy.

Elucidation of lipid nanoparticle surface structure in mRNA vaccines

Lipid nanoparticles (LNPs) have been used as a carrier for messenger RNA (mRNA) vaccines. Surface properties of LNPs are important to the stability and function of mRNA vaccines. Polyethylene-glycol (PEG) is a functional lipid at the surface of LNPs that improves colloidal stability, increases circulation time, and impacts cellular uptake. In this study, we explore in-depth lipid composition at the surface of mRNA-LNPs using high-field nuclear magnetic resonance (NMR) spectroscopy. Our results provide a unique surface lipid profile of intact LNPs identifying PEG chains and partial ionizable lipids are present with quantification capability. The surface PEG density is determined to reveal the brush-like conformation on the surface of mRNA-LNPs. Furthermore, we implement a diffusion NMR strategy for routine testing of formulated drug products during drug development. Comparative NMR analysis of different vaccine preparations and stability samples provides a global view of the mRNA-LNP surface structure for enhanced product knowledge.

In situ PEGylation of CAR T cells alleviates cytokine release syndrome and neurotoxicity.

Chimeric antigen receptor T (CAR T) cell immunotherapy is successful at treating many cancers. However, it often induces life-threatening cytokine release syndrome (CRS) and neurotoxicity. Here, we show that in situ conjugation of polyethylene glycol (PEG) to the surface of CAR T cells ('PEGylation') creates a polymeric spacer that blocks cell-to-cell interactions between CAR T cells, tumour cells and monocytes. Such blockage hinders intensive tumour lysing and monocyte activation by CAR T cells and, consequently, decreases the secretion of toxic cytokines and alleviates CRS-related symptoms. Over time, the slow expansion of CAR T cells decreases PEG surface density and restores CAR T cell-tumour-cell interactions to induce potent tumour killing. This occurs before the restoration of CAR T cell-monocyte interactions, opening a therapeutic window for tumour killing by CAR T cells before monocyte overactivation. Lethal neurotoxicity is also lower when compared with treatment with the therapeutic antibody tocilizumab, demonstrating that in situ PEGylation of CAR T cells provides a materials-based strategy for safer cellular immunotherapy.

PEG vs. zwitterions: How these surface decorations determine cellular uptake of lipid-based nanocarriers

AimTo evaluate the impact of polyethylene glycol (PEG) and zwitterionic surface decoration of lipid-based nanocarriers (NC) on cellular uptake. MethodsAnionic, neutral and cationic zwitterionic lipid-based NCs based on lecithin were compared with conventional PEGylated lipid-based NCs regarding stability in biorelevant fluids, interaction with endosome mimicking membranes, cytocompatibility, cellular uptake and permeation across intestinal mucosa. ResultsPEGylated and zwitterionic lipid-based NCs exhibited a droplet size between 100 and 125 nm with a narrow size distribution. For the PEGylated and zwitterionic lipid-based NCs only minor alterations in size and PDI in fasted state intestinal fluid and mucus containing buffer were observed, demonstrating similar bioinert properties. Erythrocytes interaction studies revealed enhanced endosomal escape properties for zwitterionic lipid-based NCs compared to PEGylated lipid-based NCs. For the zwitterionic lipid-based NCs negligible cytotoxicity on Caco-2 and HEK cells, even in the highest tested concentration of 1 % (v/v) was recorded. The PEGylated lipid-based NCs showed a cell survival of ≥75 % for concentrations ≤0.05 % on Caco-2 and HEK cells, which was considered as non-toxic. For the zwitterionic lipid-based NCs up to 60-fold higher cellular uptake on Caco-2 cells was determined compared to PEGylated lipid-based NCs. For the cationic zwitterionic lipid-based NCs the highest cellular uptake with 58.5 % and 40.0 % in Caco-2 and HEK cells, respectively, was determined. The results were confirmed visually by life cell imaging. Ex-vivo permeation experiments using rat intestinal mucosa demonstrated up to 8.6-fold enhanced permeation of the lipophilic marker coumarin-6 in zwitterionic lipid-based NCs compared to the control. Up to 6.9-fold enhanced permeation of coumarin-6 in neutral zwitterionic lipid-based NCs compared to the PEGylated counterpart was recorded. ConclusionThe replacement of PEG surfactants with zwitterionic surfactants is a promising approach to overcome the drawbacks of conventional PEGylated lipid-based NCs regarding intracellular drug delivery.

Crystalline silica particle functionalized by PEG for its collision-enhanced detection at ultramicroelectrode

Detecting individual particulate matter is highly significant in many areas, such as mine safety, environment, and human health. The analytical method based on single entity electrochemistry (SEE) has shown great potential in detecting, counting, and measuring individual particles, especially conductive metals or carbon particles, based on their unique charge transfer reactions at an ultramicroelectrode (UME). In this study, we report an innovative SEE method for improving the sensitivity of the detection of electrochemical inert crystalline silica particles by functionalizing silica particles with polyethylene glycol (PEG) molecules. The PEG surface functionalization of the silica was characterized by Fourier-transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) techniques. The morphology of silica particles was characterized by a scanning electron microscope (SEM), and a transmission electron microscope (TEM) was employed to calibrate size distribution and determine the elemental composition of silica particles. The surface charges of silica particles were measured by dynamic light scattering techniques. The collision behaviors of crystalline silica particles with UME were investigated by cyclic voltammetric experiments, which are rarely reported in the literature. The crystalline silica particles were detected based on electrochemically blocking the flux of the redox mediator at the surface of UME, which showed significant signal amplification in the proposed method. Our method was demonstrated for detecting crystalline silica functionalized with or without PEG, acquiring the limit of quantification (LOQ) values of 0.391 μM (23.45 μg/L) and 0.824 μM (49.45 μg/L), respectively, which confirmed that a more than two times improvement in LOQ could be achieved over the PEG functionalized silica particles. We further presented a theoretical model using finite element simulations with COMSOL Multiphysics. We deduced a quantitative relation between the distribution of the current step size and the size distribution of silica particles. Therefore, the reported method here provides a paradigm for SEE-based detection of electrochemically inert crystalline silica particles, which extends the previous report substantially concerning particle detection.

PH-Responsive Mucus-Penetrating Nanoparticles for Enhanced Cellular Internalization by Local Administration in Vaginal Tissue.

Low mucus penetration ability and cellular uptake seriously limit the effectiveness of local vaginal drug administration because of the rapid foreign particulate and pathogen removal property of the mucus layer. Our previous work proved that nanoparticles with a highly dense polyethylene glycol (PEG) coating can penetrate mucus rapidly (mucus-penetrating nanoparticles, MPPs) and improve drug distribution and retention at mucosal surfaces. However, the "stealth-effect" of the PEG coating also restricts cellular uptake of MPPs. In this work, we designed pH-responsive mucus-penetrating nanoparticles (pMPPs) with hydrazone bonds as the linker to conjugate a dense PEG surface coating, which enabled the pMPPs to rapidly penetrate through the mucus layer. More importantly, the acidic environment of the vaginal mucus induces slow shedding of the PEG layer, leading to a positive charge exposure to facilitate cellular uptake. Overall, pMPPs demonstrate potential as an effective delivery platform for the prophylactic and therapeutic treatment of female reproductive diseases.

The effects of gold nanoparticles with different surface coatings and sizes on biochemical parameters in mice

Objectives: Gold nanoparticles are very popular metallic nanomaterials and they have a wide spectrum of biomedical applications. This study was aimed to the production of stable and monodisperse polyethyleneimine (PEI) and polyethylene glycol (PEG) coated gold nanoparticles (AuNP20 and AuNP50), investigation of their in vivo biochemical effects in the BALB/c mice. Methods: Gold nanoparticles were synthesized and their surfaces were modified by PEI and PEG. All the necessary physicochemical characterizations were performed. After the single high dose i.v. injection (5 mg Au/kg animal weight) of the AuNP groups, their in vivo biochemical effects were evaluated multiparametrically in the mice on day 14. Results: Highly monodisperse and stable AuNPs were synthesized successfully. Significant changes in the biochemical hemogram parameters were observed depending on the surface coatings of the AuNPs. PEI and PEG surface coatings increased biocompatibility. No excessive oxidative stress response was observed in all the gold nanoparticle groups. Conclusions: It has been concluded that the surface chemistry of the particles is a more decisive parameter than the size in terms of in vivo biochemical toxicity. The surface functionalization, stability and biocompatibility of the AuNPs are important parameters for the potential biomedical applications of gold nanoparticles in future studies.

Interaction of Bis-(sodium-sulfopropyl)-Disulfide and Polyethylene Glycol on the Copper Electrodeposited Layer by Time-of-Flight Secondary-Ion Mass Spectrometry

The interactions of the functional additives SPS (bis-(sodium-sulfopropyl)-disulfide) and polyethylene glycol (PEG) in the presence of chloride ions were studied by time-of-flight secondary-ion mass spectrometry (TOF-SIMS) in combination with cyclic voltammetry measurements (CV). The PEG, thiolate, and chloride surface coverages were estimated and discussed in terms of their electrochemical suppressing/accelerating abilities. The conformational influence of both the gauche/trans thiolate molecules, as well as around C-C and C-O of PEG, on the electrochemical properties were discussed. The contribution of the hydrophobic interaction of -CH2-CH2- of PEG with chloride ions was only slightly reduced after the addition of SPS, while the contribution of Cu-PEG adducts diminished strongly. SPS and PEG demonstrated significant synergy by significant co-adsorption. It was shown that the suppressing abilities of PEG that rely on forming stable Cu-PEG adducts, identified in the form C2H4O2Cu+ and C3H6OCu+, were significantly reduced after the addition of SPS. The major role of thiolate molecules adsorbed on a copper surface in reducing the suppressing abilities of PEG rely on the efficient capture of Cu2+ ions, diminishing the available copper ions for the ethereal oxygen of PEG.

Controlling NIR-II emitting gold organic/inorganic nanohybrids with tunable morphology and surface PEG density for dynamic visualization of vascular dysfunction.

Luminescent Au nanoparticles (AuNPs) and their organic/inorganic nanohybrids are of interest due to their favorable properties and promising biomedical applications. However, most existing AuNP-based hybrid nanostructures cannot satisfy high efficiency in synthesis, deep tissue penetration, and long blood circulation simultaneously, thus cannot be employed in dynamic monitoring of biomedical applications. In this paper, using Pluronic F127 as a template, we report a robust approach for one-pot synthesis of AuNP-based organic/inorganic nanohybrids (AuNHs) with bright luminescence in the second near-infrared (NIR-II) window, tunable shape, and controllable surface polyethylene glycol (PEG) density. The nanohybrids could be controlled from a necklace-like shape with a dense brush PEG configuration to a spherical structure with a brush PEG coating, which greatly impacts the in vivo biological behavior. Compared to spherical AuNHs, the necklace-shaped AuNHs present a higher quantum yield and longer blood circulation, which are superior to most of the individual AuNPs. With these outstanding features, the necklace-shaped AuNHs could achieve real-time, dynamic visualization of vascular dysfunction, capable of directing the precise administration of thrombolytics (a medicine for the breakdown of blood clots). These findings could provide a powerful guide for designing novel NIR-II nanoprobes toward in vivo dynamic information visualization.

Diffusiophoresis of a Nonionic Micelle in Salt Gradients; Roles of Preferential Hydration and Salt-Induced Surfactant Aggregation.

Diffusiophoresis is the migration of a colloidal particle in water driven by concentration gradients of cosolutes such as salts. We have experimentally characterized the diffusiophoresis of tyloxapol micelles in the presence of MgSO4, a strong salting-out agent. Specifically, we determined the multicomponent-diffusion coefficients using Rayleigh interferometry, cloud points, and dynamic-light-scattering diffusion coefficients on the ternary tyloxapol-MgSO4-water system at 25 °C. Our experimental results show that micelle diffusiophoresis occurs from a high to a low salt concentration (positive diffusiophoresis). Moreover, our data were used to characterize the effect of salt concentration on micelle size and salt osmotic diffusion, which occurs from a high to a low surfactant concentration. Although micelle diffusiophoresis can be attributed to the preferential hydration of the polyethylene glycol surface groups, salting-out salts also promote an increase in the size of micellar aggregates, ultimately leading to phase separation at high salt concentration. This complicates diffusiophoresis description, as it is not clear how salt-induced surfactant aggregation contributes to micelle diffusiophoresis. We, therefore, developed a two-state aggregation model that successfully describes the observed effect of salt concentration on the size of tyloxapol micelles, in the case of MgSO4 and the previously reported case of Na2SO4. Our model was then used to theoretically evaluate the contribution of salt-induced aggregation to diffusiophoresis. Our analysis indicates that salt-induced aggregation promotes micelle diffusiophoresis from a low to a high salt concentration (negative diffusiophoresis). However, we also determined that this mechanism marginally contributes to overall diffusiophoresis, implying that preferential hydration is the main mechanism causing micelle diffusiophoresis. Our results suggest that sulfate salts may be exploited to induce the diffusiophoresis of PEG-functionalized particles such as micelles, with potential applications to microfluidics, enhanced oil recovery, and controlled-release technologies.

Dye-modified core/shell NaGdF4:Yb,Er@NaYF4 nanoparticles for the detection and irritation assessment of NO2−

Upconversion nanoparticles (UCNPs) have great potential applications in biological imaging, medical treatment and optical sensing. However, the development of an inorganic-organic hybrid fluorescent probe to accurately detect noxious ions and scientifically assess irritation in vivo remains a challenge. Herein, we demonstrate a fluorescent nanoprobe for detecting nitrites (NO2−) and assessing the irritation in jellyfish cell. The nanoprobe was assembled by linking neutral red to the surface of polyethylene glycol (PEG) modified NaGdF4:Yb,Er@NaYF4 core/shell nanoparticles. The nanoprobe could efficiently capture the NO2− in jellyfish and simultaneously visualize the process. It's known that the intensity ratio of green to red emission (IRGRE) of neutral red modified upconversion nanoparticles increases linearly with the amount of NO2− increasing. Moreover, the irritation of NO2− was assessed in jellyfish cells using neutral red modified fluorescent nanoprobe based on cell imaging and spectrum signals, that NO2− has irrecoverable injury to the cells. This work based on dye-modified upconversion luminescence nanoprobe is expected to shed further light on the biological analysis and detection of ions.

Effect of interparticle forces on the stability and droplet diameter of Pickering emulsions stabilized by PEG-coated silica nanoparticles

HypothesisAttractive and repulsive interparticle forces influence the stability and structure of Pickering emulsions. The effect these forces have on emulsion behavior must be better understood to improve Pickering emulsions for subsurface applications, including enhanced oil recovery and aquifer decontamination. Past work demonstrates improved emulsion stability with increasing salinity and reduced electrostatic repulsion, possibly because of interparticle networks. We hypothesize that emulsion stability is similarly improved by reducing interparticle steric repulsion. ExperimentsWe assessed the effect of interparticle forces on emulsion stability by generating decane-in-water emulsions. We used polyethylene glycol (PEG)-coated silica nanoparticles with different diameters, surface modification, and salinities to modify either vdW, steric, or electrostatic interactions. We measured emulsion stability using centrifugation, imaged emulsion droplets with optical microscopy, and analyzed images with ImageJ to calculate droplet diameters. FindingsMildly aggregated particles with 0.5–1.0 μmol/m2 surface PEG exhibit the highest emulsion stability. This optimal surface concentration maximizes a trade-off between particle repulsion and aggregation. Droplet diameters are well explained by an energy balance limited coalescence model, generated by solving DLVO equations. We find that while emulsion stability is influenced by interparticle forces, droplet size is dominated by particle-droplet interactions. These results demonstrate the potential of surface modification to significantly improve emulsion stability.

Enhancing Stability and Mucoadhesive Properties of Chitosan Nanoparticles by Surface Modification with Sodium Alginate and Polyethylene Glycol for Potential Oral Mucosa Vaccine Delivery.

Background: The present study aimed to fabricate surface-modified chitosan nanoparticles with two mucoadhesive polymers (sodium alginate and polyethylene glycol) to optimize their protein encapsulation efficiency, improve their mucoadhesion properties, and increase their stability in biological fluids. Method: Ionotropic gelation was employed to formulate chitosan nanoparticles and surface modification was performed at five different concentrations (0.05, 0.1, 0.2, 0.3, 0.4% w/v) of sodium alginate (ALG) and polyethylene glycol (PEG), with ovalbumin (OVA) used as a model protein antigen. The functional characteristics were examined by dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM)/scanning transmission electron microscopy (STEM). Stability was examined in the presence of simulated gastric and intestinal fluids, while mucoadhesive properties were evaluated by in vitro mucin binding and ex vivo adhesion on pig oral mucosa tissue. The impact of the formulation and dissolution process on the OVA structure was investigated by sodium dodecyl-polyacrylamide gel electrophoresis (SDS-PAGE) and circular dichroism (CD). Results: The nanoparticles showed a uniform spherical morphology with a maximum protein encapsulation efficiency of 81%, size after OVA loading of between 200 and 400 nm and zeta potential from 10 to 29 mV. An in vitro drug release study suggested successful nanoparticle surface modification by ALG and PEG, showing gastric fluid stability (4 h) and a 96 h sustained OVA release in intestinal fluid, with the nanoparticles maintaining their conformational stability (SDS-PAGE and CD analyses) after release in the intestinal fluid. An in vitro mucin binding study indicated a significant increase in mucin binding from 41 to 63% in ALG-modified nanoparticles and a 27–49% increase in PEG-modified nanoparticles. The ex vivo mucoadhesion showed that the powdered particles adhered to the pig oral mucosa. Conclusion: The ALG and PEG surface modification of chitosan nanoparticles improved the particle stability in both simulated gastric and intestinal fluids and improved the mucoadhesive properties, therefore constituting a potential nanocarrier platform for mucosal protein vaccine delivery.

The Effects of Various Surface Coatings of Gold Nanorods on Toxicity, Neuronal Localization, Microstructural Alterations, and In vitro/In vivo Biodistribution

AbstractWith the development of gold nanorods (AuNRs) for a number of biomedical applications, understanding their various biological effects has become important. Surface functionalization of AuNRs is attracting increasing attention with regard to toxicity, cellular uptake, localization, therapeutic potential, and biodistribution. The aim of the study is to synthesis of stable AuNRs functionalized with polyethylenimine (PEI) and polyethylene glycol (PEG), multiparametric investigation of their cellular effects on the dorsal root ganglion (DRG) primary sensory neurones, evaluation of the in vitro/in vivo biodistribution, and toxicity. PEI and PEG surface coatings increased both biocompatibility and biodistribution of the AuNRs. With the near‐infrared laser of the two‐photon microscope, very strong radiations are taken from the nucleolus parts of the neurones particularly and these localizations of the AuNRs‐PEI are confirmed by the transmission electron microscope images. Inductively coupled plasma mass spectrometry analysis shows the presence of AuNRs in liver, spleen, kidney, heart, blood, and brain within a 30 day period. It is observed that the surface coatings of the AuNRs significantly increase the biodistribution and biocompatibility. The surface functionalization, stability, and biocompatibility of the AuNRs are very important parameters for the potential nanotheranostic applications of AuNRs in the next studies.

The toxicity analysis of PVP, PVA and PEG surface functionalized ZnO nanoparticles on embryonic as well as adultDanio rerio.

Globally, the production of zinc oxide nanoparticles (ZnO NPs) increased due to its wide applications including cosmetics, paints etc., and gets accumulated in the environment during their production, use or end-of-life. The toxic effects of the NPs vary with the presence of various surface modification agents. In the current report, toxic effect of bare and capped ZnO NPs with polymeric surface modifying agent including polyvinyl alcohol (PVA), polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) is studied against adult as well as embryonic zebra fish. The surface capped NPs showed great variation in toxicity levels. It was observed that ZnO-PVA showed highly reduced toxic effects relative to ZnO-PEG and ZnO-PVP. Further, various environmental agents including humic acid can also have an impact on NPs toxicity. ZnO particles showed increased toxic effect in humic acid presence. The uptake of ZnO particles by D. rerio was high in the order of PVP-, PEG- and PVA- followed by bare-ZnO. The current investigation found that ZnO NPs dissolution and uptake are the major factors which cause the toxicity against adult as well as embryonic zebra fishes respectively.