Amino-modified Silica Nanoparticles Research Articles

Constructing flame retardant silica nanoparticles through styrene maleic anhydride copolymer grafting for PC/ABS composites

Organic-inorganic hybrid particles have been prepared by grafting styrene maleic anhydride copolymer (SMA) onto reactive amino-modified silica nanoparticles. The SMA modified SiO2 (SMA-SiO2) was incorporated into polycarbonate (PC)/acrylonitrile-butadiene-styrene (ABS) composites (4:1, wt%/wt%) with bisphenol A bis (diphenyl phosphate) (BDP) to simultaneously improve the mechanical properties and flame retardancy. The mechanical properties of the sample containing SMA-SiO2 are apparently improved compared with that of samples containing unmodified SiO2. It is found that SMA-SiO2 tends to distribute at the phase interface of PC/ABS, and therefore improves the compatibility between PC and ABS. Besides, the peak of heat release rate (PHRR) and the total smoke production (TSP) of the PC/ABS composites are decreased by the presence of SMA-SiO2. It is suggested that SMA-SiO2 can form a flame retarding shell at the phase interface to protect ABS. In summary, both the mechanical properties and flame retardancy of PC/ABS composites are significantly improved due to the selective distribution of SMA-SiO2.

Influencing foam properties of aqueous bis(2-ethylhexyl)sulfosuccinate solutions by addition of polypropylene-glycol-modified and amino-modified silica nanoparticles

The effect of silica nanoparticle (SiO2NP) addition on the air-water interfacial rheology and foam properties was investigated in aqueous solutions of bis(2-ethylhexyl)sulfosuccinate (AOT), an anionic surfactant. Two types of SiO2NPs were prepared: polypropylene-glycol-modified SiO2NPs (PPG-SiO2NPs) and amino-modified SiO2NPs (NH2-SiO2NPs). The addition of SiO2NPs stabilized the foam in the aqueous AOT solution in all cases, but the effect on the air-water interfacial behavior differed depending on the SiO2NP type. Adsorption of NH2-SiO2NPs to the air-water interface improved the air-water interfacial dilational viscoelasticity (E), enhancing foam stability. Although PPG-SiO2NPs did not adsorb to the air-water interface, the movement of AOT molecules to the air-water interface was partially suppressed by hydrophobic interaction with PPG-SiO2NPs in the bulk aqueous solution. This event limited the decrease in E, thereby stabilizing the foam.

Tailoring of silica nanoarchitecture to optimize Cu(2−x)S based image-guided chemodynamic therapy agent

The present work introduces various synthetic and post-synthetic modes of co-doping of oleate-oleylamine-stabilized Cu(2−x)S cores with red emitting [Ru(dipy)3]2+ into amino-modified silica nanoparticles (SNs) with the aim to combine chemodynamic therapy (CDT) with cellular uptake and imaging functions. Thereto, the ROS generation by the Cu(2−x)S embedded into the SNs was manifested by the spin trap facilitated ESR technique and correlated with such parameters as size of the embedded cores, content and oxidation extent of copper ions. The parameters were varied through the different extent of an oxidative degradation of the embedded Cu(2−x)S cores by their post-treating with histidine, polyethylenimine and citrate-stabilized carbon dots (CDs). The treating by CDs was chosen as the optimal post-synthetic modification of the composite SNs due to combination of CDT with high stability to aggregation. The green or dual green-red emission of the CD-treated composite SNs visualizes their cell internalization and intracellular localization by means of fluorescence and confocal microscopy methods. Correlation of cytotoxicity data of the differently treated composite SNs with their ability to ROS generation and the intracellular localization highlight the enhanced cell internalization and nuclear confinement of the CD-treated composite SNs as the factor enhancing their cytotoxicity in greater extent than the CDT function.

Excellent Water Lubrication Additives for Silicon Nitride To Achieve Superlubricity under Extreme Conditions.

Superlubricity has been recognized as the future of tribology. However, it is hard to achieve superlubricity under extreme conditions such as a high load and low sliding speed on the macroscale. In this paper, a remarkable synergetic lubricating effect between nanoparticles and silicon nitride (Si3N4) is demonstrated; this effect helps water-lubricated Si3N4 achieve superlubricity under extreme conditions successfully. Different kinds of hairy silica nanoparticles were prepared, dispersed into water, and characterized using a variety of methods. The tribological properties of water-lubricated Si3N4 with nanoparticle additives were tested using a ball-on-disk tribometer under different loads and sliding speeds. The coefficient of friction and wear scar diameter were measured and analyzed. Both the nanoparticle size and surface functional groups have a significant influence on the tribological properties of water-lubricated Si3N4. Amino-modified silica nanoparticles reduce the friction coefficient of water-lubricated Si3N4 by 82.9% under 60 N, compared with that achieved using deionized water, and induce superlubricity after the running-in process. Silica nanoparticles effectively form a homogenous film with silica gel on the worn surface under a high load and thus reduce the wear and maintain the superlubricity under extreme conditions.

Separation behavior of amorphous amino-modified silica nanoparticle/polyimide mixed matrix membranes for gas separation

In this work, amorphous amino-modified silica nanoparticles (AAMSN) were successfully synthesized via the sol-gel method and combined with the polyimide (PI) 4,4′-oxydiphthalic anhydride-2,2′-bis(trifluoromethyl) benzidine (ODPA-TFMB) to prepare mixed matrix membranes (MMMs) for gas separation. The physicochemical properties of the AAMSNs were characterized by thermogravimetric analysis, X-ray diffraction, FTIR spectroscopy, and scanning electron microscopy, and the CO2 capture and O2 enrichment behaviors of MMMs with different AAMSN contents were compared with those of a control PI membrane. The sorption isotherm and permeation data revealed that addition of AAMSNs not only increases the diffusion coefficient of the resulting membranes but also increases their adsorption coefficient due to the amorphous characteristics of the nanoparticles and good adhesion between these particles and the PI. The CO2 permeation properties and CO2/N2 selectivity of the MMM with 20 wt% AAMSN were 210.1 barrer and 30.8, respectively, while those of the control membrane were 66.7 barrer and 27.8, respectively. Mixed gas permeation results also showed that the gas permeability of the MMMs improves and their gas selectivity is maintained compared with those of the control PI membrane. The unique structure of the AAMSN/PI membrane makes it an attractive candidate for CO2 capture and O2 enrichment applications.

Cardanol-based polybenzoxazine superhydrophobic coating with improved corrosion resistance on mild steel

Cardanol-based polybenzoxazine and amino-modified silica nanoparticles were combined to develop a superhydrophobic coating (PC-a/SiO2) on mild steel for anti-corrosion coating application. The thermal curing behavior of the PC-a/SiO2 coating was studied by Fourier transform infrared spectroscopy. The durable PC-a/SiO2 coating with a static water contact angle of 162.8 ± 2.9° could retain its superhydrophobic property even after heat treatment at 250 °C for 1 h or immersion in 3.5 wt% NaCl aqueous solution for 10 days. The electrochemical measurement results indicate that the PC-a/SiO2 coating exhibits superior corrosion resistance during prolonged immersion in 3.5 wt% NaCl aqueous solution. It is expected that the cardanol-based polybenzoxazine superhydrophobic coating is promising for practical applications of corrosion resistance.

Phenol removal from aqueous solution using amino modified silica nanoparticles

Phenols constitute a widespread class of water pollutants that are generated from many industries and are known to cause a significant threat to the aquatic environment. Phenols are, therefore, considered as dangerous pollutants by global international quality organizations. This has led to a growing demand for an efficient technology for phenol removal from wastewater. Different sizes of amino-modified silica nanoparticles (SiNPs) were synthesized with 10–40nm in diameter (AMS-10 to 40), and their properties were characterized in terms of size and surface modification using transmission electron microscope (TEM), dynamic light scattering (DLS), zeta potential, elemental analyses (C, H, N), thermal gravimetric analysis (TGA) and Fourier transform infra-red (FTIR). The adsorption process was carried out utilizing batch mode experiment; the influence of various factors including pH of the medium, the contact time, the initial concentration of the adsorbate and the dose of the adsorbent on the phenol adsorption efficiency of SiNPs of various sizes were investigated. Phenol removal efficiency was found to be size-dependent, such that the phenol adsorption capacity of the SiNPs was in the following order: AMS-10>AMS-20>AMS-30>AMS-40 nm. The adsorption capacity and binding coefficient were calculated to be 35.2mg/g and 0.192mg/L, respectively, for AMS-10. The amino-modified SiNPs were found to be promising adsorbents for the phenol ions removal from the aqueous medium.

The Tribological Properties of Water Lubricated Ceramics with Silica Nanoparticle Additives

Water lubricated ceramics exhibited excellent tribological properties such as super lubricity and good thermal stability. However, long running-in period and low load-carrying capacity limited the application of water lubricated ceramics. Silica nanoparticles have been shown to be highly effective additives for oil lubrication. And because of their economic efficiency, eco-friendliness and excellent tribological properties, silica nanoparticles are considered to be great potential additives for water-based lubricant, especially for ceramic lubrication. Here, we present an exploratory study on silica nanoparticles as water-based lubricant additives for ceramic lubrication. Different silica nanoparticles were synthesized, characterized and added into water as additives. The tribological properties of silica nanoparticles as water based lubricant additives were tested. The tribological mechanism of silica nanoparticles was analyzed. It was found that silica nanoparticles dispersed well and kept stable in water. Both the running-in period and the stable period were influenced by silica nanoparticles. With the optimal 5 wt. % amino modified silica nanoparticles added into the water lubricant, the running-in time dropped by 97.0% and the average friction coefficient by 86.6% compared with the pure water.

Silica nanoparticles with Tb(III)-centered luminescence decorated by Ag0 as efficient cellular contrast agent with anticancer effect

The present work introduces composite luminescent nanoparticles (Ag0-Tb3+-SNs), where ultra-small nanosilver (4 ± 2 nm) is deposited onto amino-modified silica nanoparticles (35±6 nm) doped by green luminescent Tb(III) complexes. Ag0-Tb3+-SNs are able to image cancer (Hep-2) cells in confocal microscopy measurements due to efficient cell internalization, which is confirmed by TEM images of the Hep-2 cells exposed by Ag0-Tb3+-SNs. Comparative analysis of the cytotoxicity of normal fibroblasts (DK-4) and cancer cells (Hep-2) incubated with various concentrations of Ag0-Tb3+-SNs revealed the concentration range where the toxic effect on the cancer cells is significant, while it is insignificant towards the nonmalignant fibroblasts cells. The obtained results reveal Ag0-Tb3+-SNs as good cellular contrast agent able to induce the cancer cells death, which makes them promising theranostic in cancer diagnostics and therapy.

Cellular imaging by green luminescence of Tb(III)-doped aminomodified silica nanoparticles

The work introduces Tb(III)-centered luminescence of amino-modified silica nanoparticles doped with Tb(III) complexes for cellular imaging. For these purposes water-in-oil procedure was optimized for synthesis of 20 and 35nm luminescent nanoparticles with amino-groups embedded on the surface. The obtained results indicate an impact of the nanoparticle size in decoration, aggregation behavior and luminescent properties of the nanoparticles in protein-based buffer solutions. Formation of a protein-based corona on the nanoparticles surface was revealed through the effect of the nanoparticles on helical superstructure of BSA. This effect is evident from CD spectral data, while no any size impact on the adsorption of BSA onto aminomodified silica surface was observed. Cellular uptake of the nanoparticles studied by confocal and TEM microscopy methods indicates greater cellular uptake for the smaller nanoparticles. Cytotoxicity of the nanoparticles was found to agree well with their cellular uptake behavior, which in turn was found to be greater for the smaller nanoparticles.

Synthesis and Characterization of Doxorubicin Loaded pH-Sensitive Magnetic Core–Shell Nanocomposites for Targeted Drug Delivery Applications

In order to improve the effects of medical therapy for cancer, we prepared magnetic nanocomposites (Fe3O4@SiO2–NH–NH[Formula: see text] as doxorubicin (DOX) carriers via two different schemes. Scheme (I): the carriers were synthesized from magnetic silica nanoparticles (Fe3O4@SiO[Formula: see text] via layer by layer modification, scheme (II): the carriers were obtained from amino-modified magnetic silica nanoparticles (Fe3O4@SiO2–NH[Formula: see text] synthesized by one-step, and followed by surface modification. In order to load DOX effectively, the surface of the carriers were further modified to make the surface with a large number of hydrazine bonds which can form a pH-sensitive bond (hydrazone bond) with DOX. The two kinds of carriers both exhibited a size around 80[Formula: see text]nm, high stability and superparamagnetic behavior. However, DOX-loaded carriers (Fe3O4@SiO2–DOX(2)) performed relatively poorer performance in terms of drug loading and releasing (the loading efficiency of DOX decreased from 67.33% to 42.15%, while the releasing efficiency of DOX decreased from 66.16% to 62.23% within 72[Formula: see text]h at pH 4.0). Water-soluble tetrazolium salts (WST-1) assays in cancer cells (Hela) demonstrated that the Fe3O4@SiO2–DOX presented high anti-tumor activity, while the carriers were nearly nontoxic. Thus, the results suggested that the magnetic nanocomposites synthesized by the two different methods both can be employed to deliver DOX, while the carriers obtained via the first method may perform better and would be applied in the field of cancer therapy in the future.

Surface decoration of silica nanoparticles by Pd(0) deposition for catalytic application in aqueous solutions

Abstract The work introduces chemical and electrochemical synthetic routes to obtain Pd(0) nanoparticles (PdNPs) deposited onto silica supports in aqueous media. The former route is performed through reduction of Na 2 [PdCl 4 ] by ascorbic acid in the presence of amino-modified silica nanoparticles (SiO 2 –NH 2 ). The time-dependent variation of pH and the reductant concentration is the simple synthetic route to get uniform deposition of 215 nm sized silica supports by Pd(0) nanoparticles (3–10 nm). The methylviologen-mediated electrochemical synthetic route results in small PdNPs (3–9 nm) located both onto and beyond the silica supports. Thus, the chemical synthetic route provides more homogeneous Pd(0)–SiO 2 –NH 2 aqueous colloids. The results reveal that attractive interactions of amino/ammonium groups of SiO 2 –NH 2 with both [PdCl 4 ] 2− and ascorbate-stabilized Pd(0) seeds are the key reasons for the better Pd(0)-deposition onto silica supports. The chemically deposited Pd(0)–SiO 2 –NH 2 nanoparticles catalyze the chemiluminescence of luminol resulted from the H 2 O 2 -facilitated oxidation in alkaline aqueous solutions.

Amino-functionalized silica nanoparticles for improved enantiomeric separation in capillary electrophoresis using carboxymethyl-β-cyclodextrin (CM-β-CD) as a chiral selector

We report on the use of amino-modified silica nanoparticles (SiNPs) as an additive to the background electrolyte solution to enhance the chiral selectivity of in capillary electrophoresis that is induced by the presence of a small quantity of carboxymethyl-β-cyclodextrin (CM-β-CD). The modified SiNPs were characterized by transmission electron microscopy, elemental analysis and their zeta potential. The method was applied to the separation of four alkaline drugs (ephedrine, chlorpheniramine, propranolol and amlodipine). The addition of the modified SiNPs to the background electrolyte results in a distinct improvement in the separation power, especially when the capillary was pretreated with high concentration of particle suspensions prior to separation. The effects of fractions of modified SiNPs and organic modifier, of the thickness of the SiNP coating layer on the capillary wall were investigated. Under optimum experimental conditions, all the racemates investigated were separated with improved resolution, thus indicating the potential of the method in the field of enantiomeric separation.

Development of surface imprinted core–shell nanoparticles and their application in a solid-phase dispersion extraction matrix for methyl parathion

Applying molecular imprinting techniques to the surface of functionalized SiO2 allows the preparation of molecularly imprinted polymers (MIPs) with accessible, high affinity and surface exposed binding sites. This paper demonstrates a new strategy for producing such hybrid organic–inorganic surface imprinted silica nanoparticles for specific recognition of methyl parathion. The technique provides surface grafting imprinting in chloroform using amino modified silica nanoparticles as supports, acrylamide as the functional monomer, γ-methacryloxypropyl trimethoxy silane as the grafting agent, and methyl parathion as a template. The amino propyl functional monomer layer directs the selective occurrence of imprinting polymerization at the silica surface through copolymerization of grafting agents with functional monomers, but also acts as an assistive monomer to drive the template into the formed polymer shells to create effective recognition sites. The resulting MIPs-SiO2 nanoparticles display three-dimensional core–shell architectures and large surface areas. The molecularly imprinted shell provides recognition sites for methyl parathion, with the materials exhibiting excellent performance for selecting the template. Using MIPs-SiO2 nanoparticles as a matrix of solid-phase dispersion extraction sorbents, trace amounts of methyl parathion are selectivity extracted from pear and green vegetable samples while simultaneously eliminating matrix interferences, attaining recoveries of 84.7–94.4% for the samples.

Synthesis and anticorrosive properties of electroactive polyimide/SiO2 composites

In this study, a series of electroactive polyimide/SiO2 (EPIS) composite materials containing conjugated segments of electroactive amino‐capped aniline trimer (AT) unit were successfully prepared. First of all, the amino‐modified silica (AMS) particles of ∼100 nm in diameter were synthesized by performing the conventional base‐catalyzed sol–gel reactions. Subsequently, the AMS nanoparticles were blending into the polymerization reactions between AT and 4,4′‐(4,4′‐isopropylidenediphenoxy)‐bis(phthalic anhydride), leading to the formation of EPIS composites. The as‐prepared EPIS materials in the form of coating on cold‐rolled steel (CRS) electrode were found to be much superior in corrosion protection over those of non‐electroactive polyimide and EPI materials based on a series of electrochemical corrosion measurements in saline. The significant enhancement in corrosion protection of EPIS coatings on CRS electrodes might probably be attributed to the redox catalytic property of organic EPI inducing the formation of passive metal oxide layer and the barrier property of well‐dispersed AMS nanoparticles existed in EPI matrix. POLYM. COMPOS., 35:617–625, 2014. © 2013 Society of Plastics Engineers

Sorption-assisted surface conjugation: a way to stabilize laccase enzyme

Enyzme immobilization on solid surfaces is one of the most relevant methods to improve enzyme activity and stability under harsh conditions over extended periods. A typically interesting application is the immobilization of laccases, multicopper enzymes oxidizing aromatic compounds, to solid surfaces in order to develop valuable tools for the elimination of micropollutants in wastewater. Laccase of the white-rot fungus Coriolopsis polyzona has been successfully immobilized on fumed silica nanoparticles using a novel method. It consists in the sorption of the enzyme to amino-modified silica nanoparticles and the subsequent covalent cross-linking using glutaraldehyde as a homobifunctional linker. The so-produced nanoparticulate material has been characterized by means of scanning electron microscopy and Brunauer-Emmett-Teller surface area analysis revealing modifications of the surface structure and area during the coupling procedure. Laccase immobilization on spherical nanoparticles produced according to the method of Stöber has been shown to be much less efficient than on fumed silica nanoparticles. Long-term stability assays revealed that the novel developed method allows a drastic stabilization of the enzyme. In real wastewater, 77% of the laccase activity remained on the nanoparticles over 1 month, whereas the activity of free laccase dropped to 2.5%. The activity loss on the nanoparticles resulted from partial inactivation of the immobilized enzymes and additional release into the surrounding solution with subsequent fast inactivation of the free enzymes, since almost no activity was found in the supernatants.

Advanced anticorrosive coatings prepared from electroactive epoxy–SiO 2 hybrid nanocomposite materials

A series of electroactive epoxy/amino-SiO 2 nanocomposite materials containing conjugated segments of electroactive amino-capped aniline trimer (ACAT) unit were successfully prepared. First of all, the amino-modified silica (AMS) particles of ∼50 nm in diameter were synthesized by performing the conventional base-catalyzed sol–gel reactions of tetraethyl orthosilicate (TEOS) in the presence of (3-aminopropyl)-trimethoxysilane (APTES) molecules. Subsequently, the AMS nanoparticles were blended into the epoxy ring-opening polymerization reactions between amino-terminated aniline trimer (ACAT)/T-403 and DGEBA, leading to the formation of electroactive epoxy resin–silica hybrid nanocomposites (EES). Furthermore, the redox behavior of as-prepared EES materials was identified by the electrochemical cyclic voltammetry studies. It should be noted that the as-prepared electroactive hybrid materials in the form of coating on cold-rolled steel (CRS) electrode were found to be much superior in corrosion protection over those of non-electroactive epoxy (NEE) and electroactive epoxy (EE) materials based on a series of electrochemical corrosion measurements in saline. The possible mechanism for the advanced enhancement of corrosion protection of EES coatings on CRS electrode could be interpreted as follows: (1) electroactive epoxy coatings may act as physical barrier coating; (2) redox catalytic capabilities of ACAT units existed in electroactive epoxy may induce the formation of passive metal oxide layers on CRS electrode, as further evidenced by SEM and ESCA studies; (3) well-dispersed AMS nanoparticles in EES matrix could act as effective hinder to enhance the oxygen barrier property of electroactive epoxy matrix, the result could be demonstrated by gas permeability analysis (GPA). Electroactive epoxy/SiO 2 nanocomposites were identified by a series of electrochemical measurements such as corrosion potential ( E corr ), polarization resistance ( R p ), corrosion current ( I corr ) and electrochemical impedance spectroscopy (EIS) studied in 5 wt% NaCl electrolyte.

Comparatively Electrochemical Studies at Different Operational Temperatures for the Effect of Layered Silicate and Spherical Silica on the Anticorrosion Efficiency of PANI Nanocomposite Coatings

In this paper, a series of PANI nanocomposites have been successfully prepared by in situ oxidative polymerization. The as-prepared PANI nanocomposites were subsequently characterized by WAXRD patterns and TEM. It should be noted that the nanocomposite coating containing 3 wt-% of organophilic clay loading was found to exhibit an observable enhanced corrosion protection on cold-rolled steel (CRS) electrode at higher operational temperature of 50 degrees C, which was even better than that of uncoated and electrode-coated with PANI or PANI nanocomposites with 3 wt-% of amino-modified silica nanoparticles alone at room temperature of 30 degrees C based on the electrochemical parameter evaluations (e.g., E(corr), R(p), I(corr), R(corr) and impedance). The vapor permeability property at three different operational temperatures of PANI and PANI nanocomposite membranes were investigated by vapor permeability analyzer (VPA). Effect of material composition on the molecular weight, optical properties and surface hydrophobicity of neat PANI and PANI nanocomposite, in the form of membrane and solution, were studied by gel permeation chromatography (GPC), ultraviolet-visible absorption spectra and contact-angle measurements, respectively. Finally, electrical conductivity at three different operational temperatures of PANI and PANI nanocomposite powder-pressed pellets was also investigated through the measurements of standard four-point-probe technique.

Surface modification of poly(ethylene-co-acrylic acid) with amino-functionalized silica nanoparticles

In this work we studied the possibility to achieve a hybrid-surface through the modification, via a facile wet chemical process, of the surface of films of poly(ethylene-co-acrylic acid) (EAA) with amino-modified silica nanoparticles. Films of EAA were preliminarily activated by the introduction of –COCl groups on their surface. Silica nanoparticles were thereafter covalently bound on the polymeric surface as confirmed by FTIR, ATR-FTIR, XPS, NMR and SEM determinations. The nanoparticles formed a multilayer on the film surface and covered almost uniformly the whole film surface. Direct measurements of superficial amino groups by titration allowed us to detect a concentration of about 18 nmol cm−2. The presence of this uniform layer of nanoparticles bearing polar groups strongly changed the wettability of the material as confirmed by static contact angle measurements that passed from 87° of the neat EAA to about 30° of the amino-functionalized silica nanoparticles modified material.

Preparation, Structure, and Imaging of Luminescent SiO2 Nanoparticles by Covalently Grafting Surfactant-Encapsulated Europium-Substituted Polyoxometalates

A novel route to the preparation of luminescent silica nanoparticles and coloration for living cells was demonstrated in this article. A europium-substituted polyoxometalate was encapsulated by a hydroxyl-group-terminated double-chain quaternary ammonium cation through an ion replacement process, yielding an organic-inorganic complex with core-shell structure bearing hydroxyl groups located at the periphery. The introduction of -OH groups not only increased the solubility of the complex in polar solvents but also caused it to embed into the inner matrix of silica nanoparticles covalently and be well-dispersed through an in situ sol-gel reaction with tetraethyl orthosilicate. Elemental analysis and spectral characterization confirmed the formation of prepared complexes with the anticipated chemical composition. Scanning and transmission electron microscopy images illustrated the size change of luminescent nanoparticles with smooth surfaces and well-dispersed polyoxometalate complexes inside of the silica matrix. X-ray photonic spectra and ζ-potential measurements revealed the chemical association between the silica matrix and the complex. Luminescent spectral characterization indicated the well-retained photophysical property of Eu-substituted polyoxometalate in silica nanoparticles. The surface amino-modified silica nanoparticles were applied to cell coloration, and the dyed Hela cells were observed through laser confocal fluorescence microscopy.