Nanoparticle-filled capillary electrophoresis for the separation of long DNA molecules in the presence of hydrodynamic and electrokinetic forces

The Apoptotic, Oxidative and Histological Changes Induced by Different Diameters of Sphere Gold Nanoparticles (GNPs) with Special Emphasis on the Hepatoprotective Role of Quercetin

Purpose

Gold nanoparticles (GNPs) as pharmaceutical and drug delivery tools exhibited harmful effects on human health and other living species. Quercetin (Qur) reveals various pharmacological effects specially antioxidant, anti-inflammatory and antiapoptotic. This study is directed to investigate hepatotoxicity of GNPs, in addition, to assess the impact of Qur in mitigating the toxicological effects of GNPs.

Methods

Groups of rats were treated with or without sphere GNPs (10, 20 and 50 nm) and Qur (200 mg/kg b.wt.). Blood and liver samples from euthanized rats were subjected to biochemical, hematological, histopathological, and immunohistochemical investigations.

Results

In comparison with 20 and 50 nm treated groups, the 10 nm GNPs significantly increased serum hepatic enzymes, aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and bilirubin. These 10 nm GNPs were associated with oxidative stress and markedly decreased antioxidant enzymes: catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase (SOD). Immunohistochemically, 10 nm GNPs expressed intense positive signals in nuclei of hepatocytes when stained with anti-caspase-3 antibody confirming extensive apoptosis. Pre-cotreatment with Qur decreased all tested hepatic enzymes and increased serum level of antioxidant enzymes compared to 10 nm GNPs. Qur treatment strongly exhibited anti-Ki67 antibody (proliferative marker) indicating high proliferation of hepatic parenchyma. Histopathologically, 10 nm GNPs revealed diffuse hydropic degenerations, severe sinusoidal congestion, coagulative necrosis, sever steatosis and diffuse hemosiderosis within the hepatic parenchyma. Qur treatment ameliorated most of these pathological effects.

Conclusion

The smaller diameters of GNPs induce potential oxidative stress, cytotoxic, and apoptotic effects in hepatic tissues rather than larger ones. In addition, Qur demonstrated a significant prophylactic role against hepatotoxicity of GNPs.

Gold and silver nanoparticles functionalized with 4',7-dihydroxyflavone exhibit activity against Leishmania donovani

Leishmaniasis is a neglected tropical disease that has been burdening the world for over a century. Though there are drugs to treat leishmaniasis, the repertoire suffers several drawbacks like toxicity and low therapeutic value. Therefore, there is a rising concern to develop new anti-leishmanial strategies. In this study, we report, for the first time, the one-pot synthesis method and functionalization of gold and silver nanoparticles with 4',7-dihydroxyflavone (Au-47DHF and Ag-47DHF)) and their anti-leishmanial activity. Oval and spherical-shaped Au-47DHF nanoparticles were obtained with an average size of 5.8 ± 0.1 nm and while synthesized dodecahedron-shaped Ag-47DHF had an average size of 25.1 ± 1 nm. The zeta potential of Au-47DHF and Ag-47DHF were measured to be stable with values of 40 mV and 60 mV, respectively. The functionalization of nanoparticles with 4',7-dihydroxyflavone was confirmed by FTIR spectra. Both Au-47DHF and Ag-47DHF exhibited promising anti-leishmanial activity against the promastigote forms with IC₅₀ values of 0.1226 ± 0.02 µg/ml and 0.8483 ± 0.14 µg/ml, respectively. The nanoparticles were also capable of anti-intracellular amastigote activity with 0.121 ± 0.36 µg/ml and 0.215 ± 0.85 µg/ml for Au-47DHF and Ag-47DHF, respectively. Interestingly, the treatment with Au-47DHF and Ag-47DHF nanoparticles generated high ROS concentrations in the parasites suggesting a ROS-mediated anti-leishmanial activity of Au-47DHF and Ag-47DHF. Concluding from the results, we present here a novel synthesis method of Au-47DHF and Ag-47DHF nanoparticles that have immense potential to be anti-leishmanial agents.

Green synthesis and bactericidal activities of isotropic and anisotropic spherical gold nanoparticles produced using Peganum harmala L leaf and seed extracts

Shape, size, and homogeneity affect the biological activity of gold nanoparticles (AuNPs) in nanomedicine and catalytic applications. Here we biosynthesized monodispersed isotropic and polydispersed anisotropic spherical AuNPs from leaf and seed extract broths of the medicinal plant Peganum harmala L. (Ph. L). Synthesized AuNPs were characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy (FT-IRS), field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The antimicrobial activity of AuNPs against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) human pathogens was also assessed. Leaf- and seed-derived AuNPs had characteristic localized surface plasmon resonances of 530 and 578 nm, respectively. TEM, FE-SEM, EDX, and XRD revealed the formation of elemental face-centered cubic spherical monodispersed isotropic AuNPs of average size 43.44 nm and polydispersed anisotropic AuNPs of average size 52.04 nm from leaf and seed extract broths, respectively. FT-IR revealed polyphenols and alcohols as responsible for AuNP capping, reduction, and protection. Anisotropic AuNPs showed no antibacterial activity, whereas isotropic AuNPs showed good inhibition of both E. coli and S. aureus. This represents a simple and ecofriendly protocol for the green synthesis of monodispersed isotropic spherical AuNPs, which may have value in a variety of applications.

Recent advances in nanomaterial-based capillary electrophoresis

This review gives a summary of applications of different nanomateials, such as gold nanoparticles (AuNPs), carbon-based nanoparticles, magnetic nanoparticles (MNPs), and nano-sized metal organic frameworks (MOFs), in electrophoretic separations. This review also emphasizes the recent works in which nanoparticles (NPs) are used as pseudostationary phase (PSP) or immobilized on the capillary surface for enhancement of separation in CE, CEC, and microchips electrophoresis.

Biofabrication of gold nanoparticles by Lyptolyngbya JSC-1 extract as super reducing and stabilizing agents: Synthesis, characterization and antibacterial activity

This study describes the first ever utilization of cell free aqueous extract of cyanobacterium Leptolyngbya JSC-1 as a source of strong reducing and stabilizing agents for the optimal biofabrication of gold nanoparticles (AuNPs) through an eco-friendly synthetic route. Well dispersed crystalline AuNPs of spherical morphology with a particle size of 100-200 nm were prepared. FTIR spectral analysis was then performed to characterize the possible functionalities of JSC-1 extract, mainly involved in stabilizing and formation of AuNPs. Based on the redox potential of JSC-1 extract, it was further confirmed that the extract provide a strong reducing environment in the reaction medium and causes reduction of gold ions. The resultant AuNPs were then explored to find out their photo-catalytic activity for methylene blue and antibacterial activities against E. coli (18 ± 2 mm) and S. aureus (14 ± 2 mm). It has been mechanistically identified that AuNPs caused bacterial membrane damage and cell disruption by inducing the production of intracellular reactive oxygen species (ROS). Together, these finding reveals that biochemically capped AuNPs are the promising antibacterial agents that induce oxidative stress in the two bacterial species evaluated and cause their membrane disruption leading to cell leakage and death.

Cytotoxicity of spherical gold nanoparticles synthesised using aqueous extracts of aerial roots of Rhaphidophora aurea (Linden ex Andre) intertwined over Lawsonia inermis and Areca catechu on MCF-7 cell line

A facile synthesis of gold nanoparticles (GNPs) using the aqueous extracts of the aerial roots of Rhaphidophora aurea (Linden ex Andre) intertwined over Lawsonia inermis and Areca catechu was carried out under different conditions, namely room temperature, higher temperature, sonication, solar irradiation and pH variation. The surface plasmon resonance (SPR) band at 536 and 575 nm obtained in UV-visible spectrum revealed the formation of AuNP's. The sharp SPR band of the synthesised nanogold indicates the formation of spherical-shaped and uniform-sized nanoparticles. The TEM analysis revealed spherical nanogold particles of size 35 and 10 nm for MM and MP extracts. The secondary metabolites present in the aqueous extract are suggested to be responsible for the reduction of metal ions to metal nanoparticles as evidenced from results of FTIR analysis. Rapid synthesis of GNPs by sunlight is the production of microscopic grains of gold due to the dissociation of gold chloride. This may induce the reaction between secondary metabolites and gold chloride solutions and results in GNPs. The cytotoxic activity of the synthesised nanogold studied against human breast cancer cells (MCF-7) by 3-[4,5-dimethylthiazol-2-yl]2,5-diphenyltetrazolium bromide assay showed significant activity at higher concentration.

Recent advances in plant-mediated engineered gold nanoparticles and their application in biological system

For biosynthesis of gold nanoparticles different parts of a plant are used as they contain metabolites such as alkaloids, flavonoids, phenols, terpenoids, alcohols, sugars and proteins which act as reducing agents to produce nanoparticles. They also act as capping agent and stabilizer for them. They are used in medicine, agriculture and many other technologies. The attention is therefore focussed on all plant species which have either aroma or colour in their leaves, flowers or roots for the synthesis of nanoparticles because they all contain such chemicals which reduce the metal ions to metal nanoparticles. The size and morphology of gold nanoparticles is dependent on the biogenic-synthetic route, incubation time, temperature, concentration and pH of the solution. In this review, we have discussed the latest developments for the fabrication of gold nanoparticles from herbal extract, their characterization by UV-vis., Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, X-ray diffraction, atomic force microscopy, energy-dispersive X-ray spectroscopy, dynamic light scattering and Zeta Potential techniques. Their application in drug delivery, cancer treatment, catalysis and as antimicrobial agent has also been discussed.

Application of gold nanoparticles produced by laser ablation for immunochromatographic assay labeling

Nanodispersed gold is widely used as a marker in different analytical systems. For such purposes, it is usually obtained by the reduction of salts. This work studied the potential analytical applications of nanodispersed gold obtained by laser ablation because gold produced with this method has no chemical coating. The nanoparticles produced were characterized by transmission electron microscopy and spectrophotometry. The average size of the particles was 24.5 nm. Concentration dependences of antibody immobilization on ablative gold were obtained. With the use of antibody-conjugated nanoparticles, an immunochromatographic system was constructed for the detection of zearalenone mycotoxin. This immunoassay was characterized by a detection limit of 0.1 ng/ml antigen with an assay duration of only 15 min, which is on par with current test systems comprising nanodispersed gold obtained by chemical reduction. The simplicity of ablative dispersing makes this a prospective method for the labeling of various antibodies for analytical use.

Silver and gold nanoparticles from Sargentodoxa cuneata: synthesis, characterization and antileishmanial activity

Promising antileishmanial properties were observed with Sargentodoxa cuneata mediated Ag and AuNPs. This study opens a platform for the synthesis of new leishmanicidal agents.

Use of nanomaterials in capillary and microchip electrophoresis

This review gives an overview of different separation strategies with nanomaterials and their use in capillary electrophoresis (CE) and capillary electrochromatography, as well as in microchip electrophoresis, including metal and metal oxide nanoparticles, carbon nanotubes, fullerene and polymer nanoparticles, as well as silica nanoparticles. The paper highlights the new developments and innovative applications of nanoparticles as pseudostationary phases or immobilized on the capillary surface for CE separation. The separation and characterization of target nanoparticles with different sizes by CE are reviewed likewise.

Ultrafast, efficient separations of large-sized dsDNA in a blended polymer matrix by microfluidic chip electrophoresis: a design of experiments approach

Double-stranded (ds) DNA fragments over a wide size range were successfully separated in blended polymer matrices by microfluidic chip electrophoresis. Novel blended polymer matrices composed of two types of polymers with three different molar masses were developed to provide improved separations of large dsDNA without negatively impacting the separation of small dsDNA. Hydroxyethyl celluloses with average molar masses of ∼27  kDa and ∼1  MDa were blended with a second class of polymer, high-molar mass (∼7  MDa) linear polyacrylamide. Fast and highly efficient separations of commercially available DNA ladders were achieved on a borosilicate glass microchip. A distinct separation of a 1-kb DNA extension ladder (200-40,000  bp) was completed in 2  min. An orthogonal design of experiments was used to optimize experimental parameters for DNA separations over a wide size range. We find that the two dominant factors are the applied electric field strength and the inclusion of a high concentration of low-molar mass polymer in the matrix solution. These two factors exerted different effects on the separations of small dsDNA fragments below 1  kbp, medium dsDNA fragments between 1 and 10  kbp, and large dsDNA fragments above 10  kbp.

Salt-mediated self-assembly of thioctic acid on gold nanoparticles

Self-assembled monolayer (SAM) modification is a widely used method to improve the functionality and stability of bulk and nanoscale materials. For instance, the chemical compatibility and utility of solution-phase nanoparticles are often improved using covalently bound SAMs. Herein, solution-phase gold nanoparticles are modified with thioctic acid SAMs in the presence and absence of salt. Molecular packing density on the nanoparticle surfaces is estimated using X-ray photoelectron spectroscopy and increases by ∼20% when molecular self-assembly occurs in the presence versus the absence of salt. We hypothesize that as the ionic strength of the solution increases, pinhole and collapsed-site defects in the SAM are more easily accessible as the electrostatic interaction energy between adjacent molecules decreases, thereby facilitating the subsequent assembly of additional thioctic acid molecules. Significantly, increased SAM packing densities increase the stability of functionalized gold nanoparticles by a factor of 2 relative to nanoparticles functionalized in the absence of salt. These results are expected to improve the reproducible functionalization of solution-phase nanomaterials for various applications.

Silica spheres coated with C18-modified gold nanoparticles for capillary LC and pressurized CEC separations

Nonporous monodispersed silica spheres of 1.3 microm were coated with gold nanoparticles (AuNPs) and subsequently coated with n-octadecanethiol. By transmission electron microscopy analysis, the average diameter of the AuNPs on the silica spheres was determined to be 12 nm. The chromatographic and electrochromatographic properties of self-assembled n-octadecanethiol AuNP-coated silica microspheres (C18-AuNPs-SiO2) were investigated using a group of nonpolar PAHs. The stationary phase appears to display a characteristic reversed-phase behavior. Higher separation efficiency and shorter separation times were obtained using pressurized CEC (pCEC) compared with capillary LC (CLC). A maximum column efficiency of about 2.5x10(5) plates per meter and less than 18 min separation time for benzene were obtained in pCEC while only 66 507 plates per meter and an analysis time of nearly 100 min were observed in CLC mode. A chemical stability test of the C18-AuNPs-SiO2 stationary phase under extremely high and low pH conditions demonstrated that it is stable at pH 12 and 1 for at least 60 h. The results confirm that C18-AuNPs-SiO2 possesses a high rigidity to withstand high packing pressures and can be used as a good stationary phase for CLC and pCEC.

Investigations of the mechanism of gold nanoparticle stability and surface functionalization in capillary electrophoresis

Covalently functionalized gold nanoparticles influence capillary electrophoresis separations of neurotransmitters in a concentration- and surface-chemistry-dependent manner. Gold nanoparticles with either primarily covalently functionalized carboxylic acid (Au@COOH) or amine (Au@NH(2)) surface groups are characterized using extinction spectroscopy, transmission electron microscopy, and zeta potential measurements. The impact of the presence of nanoparticles and their surface chemistry is investigated, and at least three nanoparticle-specific mechanisms are found to effect separations. First, the degree of nanoparticle-nanoparticle interactions is quantified using a new parameter termed the critical nanoparticle concentration (CNC). CNC is defined as the lowest concentration of nanoparticles that induces predominant nanoparticle aggregation under specific buffer conditions and is determined using dual-wavelength photodiode array detection. Once the CNC has been exceeded, reproducible separations are no longer observed. Second, nanoparticle-analyte interactions are dictated by electrostatic interactions which depend on the pK(a) of the analyte and surface charge of the nanoparticle. Finally, nanoparticle-capillary interactions occur in a surface-chemistry-dependent manner. Run buffer viscosity is influenced by the formation of a nanoparticle steady-state pseudostationary phase along the capillary wall. Despite differences in buffer viscosity leading to changes in neurotransmitter mobilities, no significant changes in electroosmotic flow were observed. As a result of these three nanoparticle-specific interactions, Au@NH(2) nanoparticles increase the mobility of the neurotransmitters while a smaller opposite effect is observed for Au@COOH nanoparticles. Understanding nanoparticle behavior in the presence of an electric field will have significant impacts in separation science where nanoparticles can serve to improve either the mobility or detection sensitivity of target molecules.

Applications of gold nanoparticles in cancer nanotechnology

It has been almost 4 decades since the "war on cancer" was declared. It is now generally believed that personalized medicine is the future for cancer patient management. Possessing unprecedented potential for early detection, accurate diagnosis, and personalized treatment of cancer, nanoparticles have been extensively studied over the last decade. In this review, we will summarize the current state-of-the-art of gold nanoparticles in biomedical applications targeting cancer. Gold nanospheres, nanorods, nanoshells, nanocages, and surface enhanced Raman scattering nanoparticles will be discussed in detail regarding their uses in in vitro assays, ex vivo and in vivo imaging, cancer therapy, and drug delivery. Multifunctionality is the key feature of nanoparticle-based agents. Targeting ligands, imaging labels, therapeutic drugs, and other functionalities can all be integrated to allow for targeted molecular imaging and molecular therapy of cancer. Big strides have been made and many proof-of-principle studies have been successfully performed. The future looks brighter than ever yet many hurdles remain to be conquered. A multifunctional platform based on gold nanoparticles, with multiple receptor targeting, multimodality imaging, and multiple therapeutic entities, holds the promise for a "magic gold bullet" against cancer.

Surfactant coated fullerenes C60 as pseudostationary phase in electrokinetic chromatography

In the present paper, surfactant coated fullerenes C(60) (SC-C(60)) have been proposed as a novedous pseudostationary phase to improve separation of different aromatic compounds. The target analytes were beta-lactams antibiotics, non-steroidal anti-inflammatory drugs and amphenicols. In all cases, the analytes interacted with the pseudostationary phase producing an important enhancement on resolution. The results were compared with those obtained with surfactant coated carbon nanotubes (single-walled and multi-walled nanotubes), showing that in the proposed conditions, fullerenes C(60) were advantageous as interactions between the analytes and the pseudostationary phase were more effective. Finally, the procedure was applied to pharmaceuticals and urine samples, with satisfactory results.

Use of nanoparticles in capillary and microchip electrochromatography

Applications of nanoparticles are of rising interest in separation science, due to their favorable surface-to-volume ratio as well as their applicability in miniaturization. A stationary phase with large surface area in combination with an electroosmotic flow-driven system has great potential in a highly efficient separation system. This review covers the use of various nanoparticles as stationary or pseudostationary phase in capillary and microchip electrochromatography. The use of nanoparticles in pseudostationary phase capillary electrochromatography and open-tubular capillary electrochromatography are thoroughly discussed. The stationary and pseudostationary phases that are described include polymer nanoparticles, gold nanoparticles, silica nanoparticles, fullerenes and carbon nanotubes.

Silica nanoparticles as pseudostationary phase for protein separation

This paper investigated the potential use of silica nanoparticles (SNPs) as pseudostationary phase (PSP) for protein separation. The wall adsorption of SNPs as well as the influences of SNPs and poly(ethylene oxide) (PEO) were studied. The SNPs showed selectivity toward the proteins, and the concentration ratio of SNPs to PEO influenced the separation. The proteins that could not be baseline-resolved under conventional CZE mode were separated in a buffer consisting of 30 mM phosphoric acid, 0.05% PEO, and 0.05% SNPs at pH 2.37, with detection limits ranging from 2 to 45.5 ppm. The intraday and interday RSDs of the migration times were in the ranges of 2.1-2.8% (n = 5) and 2.5-3.4% (three days, n = 3 x 5 = 15), respectively.

Effects of novel quasi-interpenetrating network/gold nanoparticles composite matrices on DNA sequencing performances by CE

Gold nanoparticles (GNPs) with particle sizes of about 20, 40, and 60 nm were prepared and added into a quasi-interpenetrating network (quasi-IPN) composed of linear polyacrylamide (LPA) with different viscosity-average molecular masses of 1.5, 3.3, and 6.5 MDa and poly-N,N-dimethylacrylamide (PDMA) to form polymer/metal composite matrices, respectively. These novel matrices could improve ssDNA sequencing performances due to interactions between GNPs and polymer chains and the formation of physical cross-linking points as demonstrated by intrinsic viscosities and glass transition temperatures. The effects of the parameters in relation to quasi-IPN/GNPs matrices, such as GNP contents, GNP particle sizes, LPA molecular masses, and solution concentrations, on ssDNA sequencing performances were studied. In the presence of GNPs, the separation had the advantages of high resolution, speediness, excellent reproducibility, long shelf life and easy automation. Therefore, less viscous matrix solutions (with moderate size GNPs) due to lower solution concentration and lower-molecular-mass LPA could be used to replace more viscous solutions (without GNPs) due to higher solution concentration or higher-molecular-mass LPA to separate DNA, while the sieving performances were approximate even higher, which helped to achieve full automation especial for capillary array electrophoresis (CAE) and microchip electrophoresis (MCE).

Novel quasi-interpenetrating network/gold nanoparticles composite matrices for DNA sequencing by CE

In order to further improve ssDNA sequencing performances using quasi-interpenetrating network (quasi-IPN) as a matrix composed of linear polyacrylamide (LPA) with lower viscosity-average molecular mass (3.3 MDa) and poly(N,N-dimethylacrylamide) (PDMA), gold nanoparticles (GNPs) were prepared and added into this quasi-IPN to form polymer/metal composite sieving matrices. The studies of intrinsic viscosity and differential scanning calorimetry (DSC) on quasi-IPN and quasi-IPN/GNPs indicate that there were interactions between GNPs and polymer chains. The sequencing performances on ssDNA using quasi-IPN and quasi-IPN/GNPs (with different GNPs concentrations) as sieving matrices were studied and compared by CE at different temperatures. The results show that resolutions of quasi-IPN/GNPs were higher than those of quasi-IPN without GNPs and approximated those of quasi-IPN composed of LPA with higher MW (6.5 MDa) and PDMA without GNPs in the bare fused-silica capillaries. Furthermore, the sequencing time of quasi-IPN/GNPs was shorter than that of quasi-IPN under the same sequencing conditions. The influences of GNPs and sequencing temperature on the sequencing performances of ssDNA were also discussed. The separation reproducibility of quasi-IPN/GNPs solution was excellent and its shelf life was more than 8 months.

Analysis of double-stranded DNA by capillary electrophoresis using poly(ethylene oxide) in the presence of hexadecyltrimethylammonium bromide

The impact of hexadecyltrimethylammonium bromide (CTAB) on the separation of ds-DNA by capillary electrophoresis in conjunction with laser-induced fluorescence (CE-LIF) detection using poly(ethylene oxide) (PEO) solution is described. The use of CTAB for improved separation reproducibility and efficiency of DNA has not been demonstrated although it is widely used for controlling the magnitude and direction of electroosmotic flow in CE. With increasing CTAB concentration, the interactions of DNA with ethidium bromide (EtBr) and with the capillary wall decrease. For the separation of DNA fragments with the sizes ranging from several base pairs (bp) to 2,176 bp, a polymer solution consisting of 0.75% poly(ethylene oxide), 100 mM TB buffer (pH 8.0), 25 microg/mL EtBr, and 0.36 microg/mL CTAB is proper. Using the PEO solution, we separated a mixture of DNA markers V (pBR 322/HaeIII digest) and VI (pBR 328/BglI digest and pBR 328/HinfI digest) within 8 min at -375 V/cm, with the limit of detection of 2.0 ng/mL based on the peak height for the 18-bp DNA fragment. The method is highly efficient (>10(6)plate/m), repeatable (RSD of the migration times <1.5%), and sensitive. In addition, it is convenient to fill a capillary (75 microm in diameter) with such a low-viscosity PEO solution by syringe pushing.

Applications of nanomaterials in liquid chromatography: Opportunities for separation with high efficiency and selectivity

During recent decades, great efforts have been made to improve the chemical stability, selectivity, and separation efficiency of stationary phases in liquid chromatography. Significant progress has been achieved, especially after the introduction of nanomaterials into separation science. This review covers the applications of nanomaterials playing various roles in liquid chromatography. Future possibilities for developing nanomaterial-based stationary phases are also discussed.

Nanoparticle-based pseudostationary phases in capillary electrochromatography

During the past decades, research has been performed to enhance selectivity in CE by introducing different types of additives into the electrolyte. Research concerning this has taken many directions, especially during the last 5 years. A promising technique, which benefits from no packing or frits, is to use nanoparticles as the pseudostationary phase (PSP) in CEC. PSPs have the advantage of introducing a novel interaction phase for every analysis, which greatly simplify column exchange and circumvent contamination inherited from complex mixtures, e.g., biological samples. The field of nanoparticle-based PSPs used in CEC is covered in this review. The term CEC will be used consequently throughout this review, although some authors used the term EKC to categorize their work. Important requirements for the nanoparticles used and possible reasons for band broadening will be discussed. Applications with silica nanoparticles, polymer nanoparticles, molecularly imprinted polymer nanoparticles, gold nanoparticles, dendrimers, and polymeric surfactants as PSP will also be discussed.