Coated Gold Nanoparticles Research Articles

Synthesis, Characterization and Investigation of Water Uptake Capacity of Gelatin Coated Gold Nanoparticles

The present research work focuses on the designing of gelatin coated-Au nanoparticles and evaluating their water imbibitions capacity at different experimental conditions. Gelatin nanoparticles were synthesized by single water in oil (W/O) emulsion cross-linking technique and gold nanoparticles by Turkvitch method. For preparing these nanocarriers, ex-situ as well as in-situ methods were adopted and the prepared gelatin coated-Au nanoparticles were characterized by FTIR, SEM, TEM, XRD and in-vitro cytotoxicity techniques. The effect of various experimental conditions, such as amount of gelatin content, pH, temperature, and simulated biological fluids were investigated on the swelling behavior of nanoparticles. The as prepared gelatin coated-Au nanoparticles could be applied as nanocarriers for delivery of anticancer drugs.

Non-Enzymatic Urea Sensing Based on MWCNT Nanocomposite

In this work, we have demonstrated a urea sensor based on starch coated gold nanoparticles (S-AuNPs) and thiol group (-SH) functionalized multiwall carbon nanotube (MWCNT-SH) nanocomposite. The surface modifications of the MWCNTs are characterized using Fourier transform infrared (FTIR) and Raman spectroscopy. The surface analysis of the nanocomposite is recorded using field emission scanning electron microscope (FESEM) and field emission transmission electron microscope (FETEM). The sensor is developed on a glass substrate where silver and MWCNT-SH/S-AuNPs are used as contact electrodes and sensing material, respectively. The response of the sensor is observed over a range between 10 mg/dL to 60 mg/dL with high sensitivity and limit of detection of 0.48 mg/dL. The sensor has demonstrated almost stable performance for two months with excellent reproducibility. The developed sensor is evaluated to detect urea in a raw milk sample, where the sensor can recover urea between 85.17% and 88.73% in the milk sample. The proposed sensor has the potential to be used for milk quality assessment in households and dairy industries.

Gap-Dependent Surface-Enhanced Raman Scattering (SERS) Enhancement Model of SERS Substrate-Probe Combination Using a Polyelectrolyte Nanodroplet as a Distance Controller.

The development of surface-enhanced Raman scattering (SERS) biosensor platforms based on the sandwich combination of an SERS substrate and Raman reporter coated gold nanoparticle (AuNP) labeled with antibody has been widely performed for highly sensitive detection of biomolecules. The size of biomolecules located between these SERS-active materials dictates the sensitivity enhancement of the sensor. However, no suitable molecular size is provided. In this study, we report the gap-dependent SERS enhancement model using the combination of two SERS-active materials of 2D arrays of gold core-silver shell nanoparticles (Au@Ag core-shell NPs) as SERS-active substrates and mercaptobenzoic acid (MBA)-labeled AuNPs as SERS probes. The distance between these two materials is finely tuned using layer-by-layer assembled polyelectrolyte multilayer films. The morphology of the polyelectrolyte spacer is controlled into a droplet nanostructure, which is assumed to have a comparable shape with globular biomolecules. The well-controlled height or thickness of polyelectrolyte nanodroplet was achieved by changing number of deposition cycles. By increasing the thickness of the polyelectrolyte nanodroplet, MBA SERS intensities gradually decreased until at 40 nm-thick nanodroplet film and maintained afterward. This spacer thickness defined the limit of plasmonic coupling effect from this SERS probe-substrate combination. The SERS enhancement capability of this model was compared to conventional SERS immunoassay using three different antigen-antibody complex sizes of prostate-specific antigen, carcinoembryonic antigen, and carbohydrate antigen 19-9. Good agreement of the limitation of plasmon coupling as a function of the distance between the SERS substrate-probe combination using this developed model and SERS immunoassay was found. The finding provides valuable guidelines for immune-system selection in SERS immunosensors based on SERS substrate-probe combination.

Isolation, characterization and in-vitro antigenicity studies of outer membrane proteins (OMPs) of Salmonella gallinarum coated gold nanoparticles (AuNPs)

The development of biomimetic nanoparticles by combining the natural cellular material with synthetic nanoparticles has inspired innovative therapeutic strategies as compared to traditional line of therapeutics. Therefore, the research was conducted to prepare the outer membrane proteins (OMPs) from Salmonella gallinarum and coated on to the surface of synthetic gold nanoparticles (AuNPs). The size of the final product was characterized by Zeta sizer and Zeta potential. The coating of outer membrane proteins onto the gold nanoparticles (AuNPs) was confirmed by transmission electron microscopy (TEM). The sterility, stability and safety of the prepared antigen was confirmed by standard culture media, in biological buffer solution and in-vitro pyrogenic testing, respectively. In-vitro antigenicity of outer membrane protein alone and coated with gold nanoparticles were observed through macrophage phagocytosis assay. On the basis of results, it was anticipated that bacterial outer membrane protein has immunogenic antigenic properties and coating of bacterial outer membrane protein on the surfaces of synthetic gold nanoparticles not only preserved the complex biological characteristics of bacteria but also provided greater immune responses as compared to outer membrane protein alone. So, it was concluded that the coating of bacterial outer membrane proteins on the surface of synthetic gold nanoparticles have synergistic effects to induce the immune responses and promising potential to develop the effective antibacterial vaccine against salmonellosis in poultry birds.

Novel dual-emissive fluorescent immunoassay for synchronous monitoring of okadaic acid and saxitoxin in shellfish

In this work, we present a novel dual-emissive fluoroimmunoassay for synchronous monitoring of okadaic acid (OA) and saxitoxin (STX) using multicolor fluorescent labels composed of sulfur, phosphorous co-doped graphene quantum dots (S, P-GQDs), and ovalbumin (OVA)-coated gold nanoparticles (OVA-AuNPs). The novel OVA-AuNPs were prepared by the reduction of chloroauric acid under alkaline conditions using OVA as a reducing agent. Both S, P-GQDs and OVA-AuNPs exhibit bright fluorescence, more importantly, a large emission wavelength difference (Δλ = 156 nm) under an excitation of 400 nm and relatively independent fluorescence behavior, which are essential to realizing the dual-signal marks in a directly mixing system. Using a competitive fluorescence-linked immunosorbent assay (cFLISA) format, the dual-emissive cFLISA was successfully utilized to measure OA and STX contents in Alectryonella plicatula (commonly named as fingerprint oyster) and the detection results were in good agreement with the commercial enzyme-linked immunosorbent assay (ELISA) kits.

Reinforcing the Induction of Immunogenic Cell Death Via Artificial Engineered Cascade Bioreactor-Enhanced Chemo-Immunotherapy for Optimizing Cancer Immunotherapy.

Traditional chemo-immunotherapy can elicit T cell immune response by inducing immunogenic cell death (ICD), however, insufficient ICD limits the lasting antitumor immunotherapeutic efficacy. Herein, tadpole-ovoid manganese-doped hollow mesoporous silica coated gold nanoparticles (Au@HMnMSNs) as biodegradable catalytic cascade nanoreactors are constructed to generate intratumoral high-toxic hydroxyl radicals combined with DOX and Aspirin (ASA) for enhancing the induction of ICD and maturation of dendritic cells (DCs). The released Mn2+ can catalyze endogenous H2 O2 to hydroxyl radicals, while internal gold nanoparticles mimetic glucose oxidase (GOx) converted glucose into H2 O2 to accelerate the generation of hydroxyl radicals. On the other hand, tadpole oval-structured Au@HMnMSNs can avoid the inactivation of gold nanoparticles due to strong protein adsorption. The introduction of ASA is to recruit DCs and cytotoxic T lymphocytes (CTLs) to tumor sites and restrain the intratumoral infiltration of immunosuppressive cells by decreasing the expression of prostaglandin E2 (PGE2 ). Accordingly, this work presents a novel insight to introduce GOx-like catalytic cascade ICD nano-inducer into antitumor immunotherapy for synergistic tumor therapy.

On-demand nanoparticle-on-mirror (NPoM) structure for cost-effective surface-enhanced Raman scattering substrates

We report a robust technique to fabricate a cost-efficient Raman substrate which is composed of polyvinylpyrrolidone (PVP) coated gold nanoparticles layer on commercial aluminum foil. The layer of metal nanoparticles on the aluminum foil, i.e., the nanoparticle-on-mirror (NPoM) structure was fabricated by spraying nanoparticle colloidal solution directly on the foil. The detection limit (LOD) of NPoM substrate is investigated by performing the SERS for Rhodamine 6G (R6G) with the concentration ranging from mM to nM without any post treatment of the substrate. The findings show that the LOD of 1 nM and maximum intensity enhancement factor of ~ 24 is accomplished. Field enhancement owing to reflection from the metallic mirror is the reason behind the signal enhancement and it would be beneficial for routine clinical applications, trace chemical detection, and disease diagnostics.

Color-coded Adrenaline Assay Based on GNP@MnO2 Core-shell Nanoparticles with Dark-field Microscopy

Adrenaline (AD) is an important hormone in central nervous system of mammals, and also works as a medium to transmit signal. The abnormal level of AD in nerve tissues and biological fluids can cause a variety of diseases. In this work, we developed a simple and sensitive dark-field microscopy (DFM)-based single-particle detection (SPD) method for quantitative detection of AD in aqueous solution. MnO 2 layer of GNP@MnO 2 core-shell nanoparticles could be readily etched due to the reducibility of AD. Since the localized surface plasmon resonance (LSPR) of GNPs was sensitive to the dielectric change of local environment, the etching process resulted in an evident color change of the probe and could be easily observed in real time under dark-field microscope. The AD was thus sensitively detected in a wide linear concentration range (0.02–5 μmol/L) with a limit of detection (LOD) of 7.17 nmol/L. Moreover, this method was used for the analysis of AD content in commercial injection and satisfactory recoveries were acquired. As a consequence, the sensing assay demonstrated herein based on GNP@MnO 2 NPs showed great application prospects in molecular recognition and drug quality assay. A convenient and sensitive dark field microscopy (DFM) based single particle detection (SPD) method was proposed for adrenaline (AD) detection by MnO 2 coated gold nanoparticles (GNP@MnO 2 NPs). Compared with the traditional techniques, this method collects signal from individual particle and greatly improves the sensitivity. This study provides new insights for the ultrasensitive detection of molecules in clinical diagnosis and pharmaceutical evaluation.

Determination of Dichlorvos in Pears by Surface-Enhanced Raman Scattering (SERS) with Catalysis by Platinum Coated Gold Nanoparticles

A surface-enhanced Raman scattering (SERS) sensor is reported for the determination of dichlorvos, an organophosphate pesticide (OP), in pears. Platinum coated gold nanoparticles (Au@PtNPs) were used as secondary catalysts to provide signal amplification. Acetylcholinesterase (AChE) catalyzed the hydrolysis of acetylthiocholine to form thiocholine. Thiocholine causes the accumulation of Au@PtNPs, which changes the particle size and prevents their peroxidase-mimicking activity. Dynamic light scattering was used to characterize the particle size. Following the addition of dichlorvos, the AChE activity was inhibited, the production of thiocholine and aggregation were reduced, and the peroxidase mimicing property was retained. In the presence of 3,3′,5,5′-tetramethylbenzidine (TMB), a blue product was produced that provided strong SERS signals. The SERS method showed a linear relationship for dichlorvos concentrations from 20 to 2000 µg/L. The developed protocol had a limit of detection of 20 µg/L. This SERS sensor assay was successfully applied for the quantification of dichlorvos in pears with satisfactory recoveries from 80.25 to 94.86%.

Delivery of antisense oligonucleotides using multi-layer coated gold nanoparticles to methicillin-resistant S. aureus for combinatorial treatment

The spread of multidrug-resistant (MDR) bacterial infections has become a serious global threat. We introduce multi-layer coated gold nanoparticles (MLGNPs) delivering antisense oligonucleotides (ASOs) targeting the resistance gene of methicillin-resistant Staphylococcus aureus (MRSA), as a selective antimicrobial by restoring susceptibility. MLGNPs were prepared by multi-step surface immobilization of gold nanoparticles (GNPs) with polyethylenimine (PEI) and loaded with ASO targeting the mecA gene. The MLGNPs were shown to be efficiently internalized into various types of Gram-positive bacteria, including MRSA, Staphylococcus epidermidis, and Bacillus subtilis, which was superior to single-layer coated GNPs and free PEI polymer. The delivery of MLGNPs into MRSA resulted in up to 74% silencing of the mecA gene with high selectivity, in a dose-dependent manner. The treatment of MLGNPs to MRSA in the presence of oxacillin, a beta-lactam antibiotic, showed major suppression (~71%) of bacterial growth, due to the recovery of antibacterial sensitivity. Furthermore, the treatment of MLGNPs in a complex system showed preferential uptake into bacteria over mammalian cells, demonstrating the suitable characteristics of MLGNPs for selective delivery into bacteria. The current approach can be potentially applied for targeting various types of MDR bacterial infections by specific silencing of a resistance gene, as a combinatorial therapeutic used with conventional antibiotics.

Target-triggered DNAzyme walker with 3D walking unit for copper species sensing in serum: A multivalent binding strategy for improving the detection performance

Monitoring copper (Cu) species in bio-samples is critical for the investigation and auxiliary diagnosis of Cu-metabolism disorders. Herein, a target-triggered DNAzyme walker, consisting of Carboxyfluorescein (FAM)-labeled substrates of the Cu-DNAzyme (Cu-Sub) coated gold nanoparticles (AuNPs) ([email protected] track) and the enzyme chain of the Cu-DNAzyme (Cu-Enzy) functionalized magnetic beads ([email protected] 3D walking unit), was designed for the sensitive detection of copper species. Upon addition of copper ion (Cu2+), DNAzyme was activated and triggered the walking process, thereby releasing FAM-labeled fragments and recovering fluorescence. When compared with free-running Cu-Enzy or co-conjugated Cu-Enzy on AuNPs walking units, the [email protected] walking unit exhibited a higher cleavage efficiency, shorter detection time (40 min), and a lower limit of detection (LOD = 3 nM). This improved performance was mainly attributed to multivalent interactions between the 3D track and the 3D walking unit which dramatically increased the affinity and cleavage efficiency. Importantly, good accuracy was observed for copper species analysis in clinical serum samples (n = 130), relative to other instrumentation, inductively coupled plasma atomic emission spectrometry (ICP-AES) (P > 0.01). The serum detection data indicated that total, exchangeable and relative exchangeable Cu variables could serve as potential indicators for the auxiliary diagnosis of Cu-related disorders. Thus, our target-triggered DNAzyme walker provides improved technical support for the in-depth study of clinical Cu metabolic-related diseases.

Nanoparticles Interfere with Chemotaxis: An Example of Nanoparticles as Molecular "Knockouts" at the Cellular Level.

Engineered colloidal nanoparticles show great promise in biomedical applications. While much of the work of assessing nanoparticle impact on living systems has been focused on the direct interactions of nanoparticles with cells/organisms, indirect effects via the extracellular matrix have been observed and may provide deeper insight into nanoparticle fate and effects in living systems. In particular, the large surface area of colloidal nanoparticles may sequester molecules from the biological milieu, make these molecules less bioavailable, and therefore function indirectly as "molecular knockouts" to exert effects at the cellular level and beyond. In this paper, the hypothesis that molecules that control cellular behavior (in this case, chemoattract molecules that promote migration of a human monocytic cell line, THP-1) will be less bioavailable in the presence of appropriately functionalized nanoparticles, and therefore the cellular behavior will be altered, was investigated. Three-dimensional chemotaxis assays for the characterization and comparison of THP-1 cell migration upon exposure to a gradient of monocyte chemoattractant protein-1 (MCP-1), with and without gold nanoparticles with four different surface chemistries, were performed. By time-lapse microscopy, characteristic parameters for chemotaxis, along with velocity and directionality of the cells, were quantified. Anionic poly(sodium 4-styrenesulfonate)-coated gold nanoparticles were found to significantly reduce THP-1 chemotaxis. Enzyme-linked immunosorbent assay results show adsorption of MCP-1 on the poly(sodium 4-styrenesulfonate)-coated gold nanoparticle surface, supporting the hypothesis that adsorption of chemoattractants to nanoparticle surfaces interferes with chemotaxis. Free anionic sulfonated polyelectrolytes also interfered with cell migrational behavior, showing that nanoparticles can also act as carriers of chemotactic-interfering molecules.

Recent Advances in Inorganic Nanomaterials Synthesis Using Sonochemistry: A Comprehensive Review on Iron Oxide, Gold and Iron Oxide Coated Gold Nanoparticles.

Sonochemistry uses ultrasound to improve or modify chemical reactions. Sonochemistry occurs when the ultrasound causes chemical effects on the reaction system, such as the formation of free radicals, that intensify the reaction. Many studies have investigated the synthesis of nanomaterials by the sonochemical method, but there is still very limited information on the detailed characterization of these physicochemical and morphological nanoparticles. In this comprehensive review, recent advances in the sonochemical synthesis of nanomaterials based on iron oxide nanoparticles (Fe3O4NP), gold nanoparticles (AuNP) and iron oxide-coated gold nanoparticles (Fe3O4@Au NP) are discussed. These materials are the most studied materials for various applications, such as medical and commercial uses. This review will: (1) address the simple processing and observations on the principles of sonochemistry as a starting point for understanding the fundamental mechanisms, (2) summarize and review the most relevant publications and (3) describe the typical shape of the products provided in sonochemistry. All in all, this review’s main outcome will provide a comprehensive overview of the available literature knowledge that promotes and encourages future sonochemical work.

Electron microscopy of antibody-conjugated, lutetium-177 lanthanide gold-coated nanoparticles: Proof of concept of targeted loci—A potential theranostic agent

Following murine injection, the ultrastructural loci of nanoparticles (NPs) containing lutetium-177 (Lu-177) conjugated to an anti-thrombomodulin antibody (mAb-201b) were determined. The results confirmed prior work localizing NPs using Single Photon Emission Computed Tomography (SPECT) scans. The in vivo pharmacokinetics of these NPs were also identified. mAb-201b antibodies are primarily attracted to the thrombomodulin, a membrane protein in the endothelium of the lung vasculature. SPECT images demonstrated NPs in the lungs, liver, spleen, and proximal small bowel. Prior injection of clodronate liposomes reduced the number of circulating macrophages, which, in turn, reduced NP phagocytosis. At 24 h after injection of NPs and after final SPECT imaging, the lungs, liver, spleen, and kidneys were harvested for transmission electron microscopy. Although some NPs were found in all four organs, 85% of the injected dose was localized in type I and type II pneumocytes. Small concentrations were found in secondary lysosomes in hepatocytes, in splenic macrophages, and in an intravascular macrophage in a kidney. Importantly, there was no apoptosis or necrosis in any of the tissues, highlighting the relative safety of the radionuclide NP, whose primary interaction with non-targeted organs/tissues is in the filtration process. In addition to validating the biodistribution results of the SPECT scans carried out in our prior work, this study is proof of principle that NPs conjugated with appropriate antibodies can target specific antigens in vivo. From a theranostic perspective, these results suggest that radioactive nanoconjugates labeled with proper antigens should be able to target and destroy a variety of cancers with minimal harm to the surrounding healthy cells.

Colorimetric detection of neomycin sulfate in tilapia based on plasmonic core–shell Au@PVP nanoparticles

The rapid colorimetric detection of neomycin sulfate has been achieved using polyvinyl pyrrolidone shell coated gold nanoparticle (Au@PVP NPs) sol. We also observed that, the aggregation of Au@PVP NPs, possibly caused by the hydrogen bonds formed between neomycin sulfate and PVP shell, generates a new surface plasmon resonance absorption in the wavelength of 600 ~ 700 nm. The proposed method showed an excellent performance towards the determination of neomycin sulfate in wide linear range from 0.01 ~ 10 µM with a correlation coefficient of 0.99 and low detection limit of 1 nM. After extracted with trichloroacetic acid and treated with hot chloroform, neomycin sulfate in the tilapia fish samples was detected with satisfied recovery. Additionally, the high selectivity of Au@PVP NPs sol towards neomycin sulfate has been achieved even in presence of common interfering agents. This method has the advantages of high sensitivity, rapidity, specificity, low cost and no complicated pretreatment procedure.

Tumor cell-targeting radiotherapy in the treatment of glioblastoma multiforme using linear accelerators

Although boron neuron capture therapy (BNCT) has enabled the delivery of stronger radiation dose to glioblastoma multiforme (GBM) cells for precision radiotherapy (RT), patients in need are almost unable to access the treatment due to insufficient operating devices. Therefore, we developed targeted sensitization-enhanced radiotherapy (TSER), a strategy that could achieve precision cell-targeted RT using common linear accelerators. TSER, which involves the combination of GoldenDisk (GD; a spherical radioenhancer), 5-aminolevulinic acid (5-ALA), low-intensity ultrasound (US), and low-dose RT, exhibited synergized radiosensitization effects. Both 5-ALA and hyaluronic-acid-immobilized GD can selectively accumulate in GBM to induce chemical and biological enhancement of radiosensitization, resulting in DNA damage, escalation of reactive oxygen species levels, and cell cycle redistribution, in turn sensitizing GBM cells to radiation under US. TSER showed an enhanced therapeutic effect and survival in the treatment of an orthotropic GBM model with only 20% of the radiation dose compared to that of a 10-Gy RT. The strategy with the potential to inhibit GBM progress and rescue the organ at risk using low-dose RT, thereby improving the quality of life of GBM patients, shedding light on achieving cell-targeted RT using universally available linear accelerators. Statement of significanceWe invented GoldenDisk (GD), a radioenhancer with hyaluronic-acid (HAc)-coated gold nanoparticle (AuNP)-core/silica shell nanoparticle, to make radiotherapy (RT) safer and smarter. The surface modification of HAc and silica allows GD to target CD44-overexpressed glioblastoma multiforme (GBM) cells and stay structurally stable in cytoplasm throughout the course of RT. By combining GD with low-energy ultrasound and an FDA-approved imaging agent, 5-aminolevulinic acid (5-ALA), GBM cells were sensitized to RT leaving healthy tissues in the vicinity unaffected. The ionized radiation can further be transferred to photoelectronic products with higher cytotoxicity by GD upon collision, achieving higher therapeutic efficacy. With the newly-developed strategy, we are able to achieve low-dose precision RT with the use of only 20% radiation dose.

Fine synthesis of Prussian-blue analogue coated gold nanoparticles (Au@PBA NPs) for sorting specific cancer cell subtypes

Multiplex surface-enhanced Raman scattering (SERS) detection of markers without background in tumor biosystems has its superiority over other optical methods. Herein, we reported a strategy of quantitative discrimination of two breast cancer cell subtypes. Based on our previous studies, two kinds of Prussian blue analogue coated gold nanoparticles (Au@PBA NPs) were designed and synthesized by the replacement of Fe2+ with Pb2+ or Cu2+. Therefore, two distinct SERS emissions of C≡N bonds at 2122 cm−1 and 2176 cm−1 have been acquired. When modified with aptamers of epithelial cell adhesion molecule (EpCAM) and epidermal growth factor receptor (EGFR), which are both expressed in MCF-7 and MDA-MB-231 cell lines but in different levels, the SERS nanoprobes simultaneously identified the relative expression of these biomarkers on the cell surface, providing a good example for ratiometric detection in biosystems without any interference. Each surface marker of tumor cells corresponds to a single SERS emission. Thus, each subtype could be described in a molecular profiling way through duplex C≡N bonds-based SERS emission, which is more advanced than traditional flow cytometry method.

Core size optimized silver coated gold nanoparticles for rapid screening of tricyclazole and thiram residues in pear extracts using SERS

Silver-coated gold nanoparticles (Au@AgNPs) were optimized with different gold (Au) core sizes and modified surface with mercaptooctane (MCO) to determine fungicide residues in pear fruit extracts. The developed MCO/Au@AgNPs with a gold core size of 28 nm and silver shell thickness of 6 nm exhibited high sensitivity and significant enhancement of Raman scattering in detecting tricyclazole (TCZ) and thiram fungicides in standard and pear fruit samples. The detection limits for TCZ and thiram in the pear fruit extracts were 0.005 and 0.003 ppm with coefficients of determination of (R2) of 0.9984 and 0.9971, percent recovery ranging from 82.7 to 107.4% and 80.7 to 109.8%, and relative standard deviation (RSD) of 1.5 to 7.9% and 3.7 to 9.5%, respectively. Results showed that this easily prepared method could be employed as SERS active platforms for the rapid assessment of trace contaminants of agrochemicals in agriculture production.

Nucleolin targeted delivery of aptamer tagged Trichoderma derived crude protein coated gold nanoparticles for improved cytotoxicity in cancer cells

The present work demonstrates how the fungal crude protein extract (FE) mediated gold nanoparticles (AuNPs) functionalized with aptamer (APT) improved cytotoxicity in human lung cancer cell line (A549) and brain tumor cell line (LN229). The agarose gel electrophoresis (AGE) confirmed the conjugation of APT in FE-AuNPs. The FTIR results revealed the involvement of FE in the amalgamation of FE-AuNPs. FE-AuNPs (λmax 521 nm) had Z-average size of 19.72 ± 0.26 d. nm and PDI of 0.58 ± 0.01 with a zeta potential of -22.20 mV, whereas APT-FE-AuNPs (λmax521 nm) had the Z-average size of 167.63 ± 1.40 d. nm and PDI of 0.21 ± 0.01 with a zeta potential of -36.36 mV. Both synthesized nanoparticles exhibited less cytotoxicity in normal NIH3T3 cells, while the APT-FE-AuNPs (λmax 521 nm) showed significant cytotoxicity in A549 and LN229 cells. The cells treated with APT-FE-AuNPs (λmax 521 nm) displayed higher percentage of early apoptosis (6.97 %), apoptosis (7.08 %), and necrosis (6.63 %) than those treated with bare or APT-FE-AuNPs (λmax 565 nm) in A549 cells. The results demonstrated that the DNA aptamer (AS1411) tagged with FE-AuNPs (λmax 521 nm) increased their accumulation in cancer cells, which triggered nucleolin targeted cell cytotoxicity through nucleus damage and induction of oxidative stress.

Cell mechanics characteristics of anti-HER2 modified PPy@GNPs and its photothermal treatment of SKOV-3 cells

Nanomaterials and nanotechnology have been widely used in various fields, such as materials, chemical engineering, optics, and other disciplines. In this paper, gold nanoparticles are prepared by the hydrothermal method and treated with polypyrrole coating (PPy-GNPs). Then, the anti-HER2 protein was conjugated to polypyrrole coated gold nanoparticles, and the nanomaterials are named anti-HER2-PPy@GNPs (anti-PPy@GNPs). Their diameter is about 80–90 nm, and they show a strong absorption peak in the near-infrared band, especially under 808 nm laser irradiation. In the MTT test experiment, anti-HER2-PPy@GNPs show a significant inhibitory effect on the SKOV-3 cell. Fluorescent cytoskeletal analysis of SKOV-3 cells and atomic force microscopy (AFM) of the mechanical characteristics of the cell surface revealed that the cell micro-structure, adhesion, and Young's modulus of anti-HER2-PPy@GNPs have changed under the near-infrared illumination. These results indicate anti-HER2-PPy@GNPs has an inhibitory effect on SKOV-3 cells. AFM detects the mechanical characteristics of SKOV-3 cells. Compared with the control group, Young's modulus is increased 52.7%, while the adhesion force is decreased 14.47%.