Gold Nanocomposites Research Articles

Effect of gold nanocomposite bearing HIF-1α siRNA on radiotherapy in nasopharyngeal carcinoma cell

Purpose: To investigate the effect of gold nanocomposite carrying hypoxia-inducible factor-1α (HIF-1α) siRNA on radiosensitivity of nasopharynx cancer (NPC) cells.
 Methods: Gold nanocomposite (AuNRs-(PEI-PEG)/RGD) or (AuPPR) was first synthesized and its cytotoxicity was evaluated. Then, the expression of HIF-1α in hypoxic NPC cells was assessed. In addition, the radiation sensitivity of AuPPR bearing HIF-1α siRNA on the cells was examined under xray exposure.
 Result: Gold nanocomposite (AuPPR) carrying HIF-1α siRNA (AuPPR-HIF-1α siRNA) significantly down-regulated HIF-1α expression. Under irradiation treatment, AuPPR-HIF-1α siRNA significantly enhanced apoptosis of NPC cells by 33.76 ± 3.65 %, when compared to the control and simple AuPPR group (22.5 ± 4.16 %, p < 0.01). Furthermore, cell cycle was significantly blocked in the sub-G1 phase in AuPPR-HIF-1α siRNA radiotherapy groups, indicating severe cell damage.
 Conclusion: This study has demonstrated that AuPPR-HIF-1α siRNA is effective in improving the radiosensitivity of nasopharyngeal carcinoma cells under hypoxia, and therefore can potentially be used to improve the radiotherapy of this carcinoma

Development of Hydroxy Ethyl Cellulose based (HEC) Gold Nanocomposites Hydrogels for Antimicrobial Application

Development of Hydroxy Ethyl Cellulose based (HEC) Gold Nanocomposites Hydrogels for Antimicrobial Application

“Green” Fluorescent–Plasmonic Carbon-Based Nanocomposites with Controlled Performance for Mild Laser Hyperthermia

Fluorescent carbon nanodots are a promising nanomaterial for different applications in biophotonics, sensing and optical nanothermometry fields due to their strong fluorescence properties. However, their multi-modal applications are considerably limited, requiring the use of several nanoagents that could solve different tasks simultaneously. In this paper, we report the first experimental results on a facile “green” laser-based synthesis of multi-modal carbon–metallic nanocomposites with tuned optical performance. This simple approach leads to the appearance of finely controlled plasmonic properties in carbon-based nanocomposites whose spectral position is adapted by using an appropriate material. Thus, longer laser ablation provokes 29-fold increase in the absorption intensity of carbon–gold nanocomposites due to the increase in the metal content from 13% (30 s) to 53% (600 s). Despite strong plasmonic properties, the metal presence results in the quenching of the carbon nanostructures’ fluorescence (2.4-fold for C-Au NCs and 3.6-fold for C-Ag NCs for 600 s ablation time). Plasmonic nanocomposites with variable metal content reveal a ~3-fold increase in the laser-to-heat conversion efficiency of carbon nanodots matching the temperature range for mild hyperthermia applications. The findings presented demonstrate a facile approach to expanding the properties of chemically prepared semiconductor nanostructures due to the formation of novel semiconductor–metallic nanocomposites using a “green” approach. Together with the ease in control of their performance, it can considerably increase the impact of semiconductor nanomaterials in various photonic, plasmonic and biomedical applications.

X-ray photoelectron spectroscopy and tunable photoluminescence study of gold nanoparticles embedded in PVA films.

This article reports the systematic photoluminescence study of the various contents of gold nanocomposites in polyvinyl alcohol (PVA) films. The variations in the gold content in PVA film were 0.2, 0.5, 1.0, and 1.5wt%. All the samples were excited at two selected wavelengths; those are at 400 nm and 532 nm. On exciting the gold-PVA nanocomposite films at 400 nm the photoluminescence was observed in the region of 430-500 nm in comparison to pure PVA films that show an emission at 400 nm. However, on exciting the gold-PVA nanocomposites at 532 nm, the emission was observed at 560-650 nm with a long tail till 700 nm that is unlike the pure PVA films that do not show any emission peak in this region. This suggests that emission between 430 and 500 nm regions is due to the coordination of PVA with gold nanoparticles because PVA has an emission at 400 nm. However, the emission peak between 560 and 650 nm is entirely due to the gold nanocomposite particle. The peak also shows a smaller red-shift that is usually with the increasing nanoparticles size with the increasing content in the PVA films. The formation of gold nanoparticles was justified by X-ray diffraction (XRD) analysis which is further supported by X-ray photoelectron spectroscopy (XPS) analysis.

Carbon-Dot-Decorated Silver and Gold Nanocomposites for Antibacterial Activity and Degradation of Organic Dyes

Carbon-Dot-Decorated Silver and Gold Nanocomposites for Antibacterial Activity and Degradation of Organic Dyes

Low Conductivity Polyaniline–Gold Nanocomposite via Interfacial Polymerization: Efficient Humidity Sensing by Thin Films and Mechanistic Insights through In Situ Experiments

Low Conductivity Polyaniline–Gold Nanocomposite via Interfacial Polymerization: Efficient Humidity Sensing by Thin Films and Mechanistic Insights through <i>In Situ</i> Experiments

Gold nanoclusters-decorated graphitic carbon nitride nanocomposites with antibacterial and anti-biofilm activities

Gold nanoclusters (AuNCs) are of great potential in antibacterial field, but their unsatisfactory stability as a result of high surface free energy limits their practical applications. One efficient solution is loading the ultrasmall AuNCs onto a substrate or matrix. In this work, graphitic carbon nitride (CN) nanoparticles were firstly functionalized with imidazole groups via a photocatalytic reaction. Then, AuNCs were in-situ synthesized on surface of CN by using imidazole moieties as the reducing and stabilizing ligands via formation of Au-N bonds. Transmission electron microscopy (TEM) analysis of the obtained CN-AuNC nanocomposites verified the uniform distribution of AuNCs with a mean size of 1.8 nm on CN surface. Since the coordination strength of Au-N bond is weaker than that of Au-S bond, ligand exchange can occur for the imidazole-protected AuNCs due to ligand exchange in the presence of thiol compounds. Accordingly, the obtained CN-AuNC nanocomposites exhibited thiol depletion ability. The AuNCs slowly released from the CN surface can enter Escherichia coli (E. coli) due to their ultrasmall size, consume bio-thiols reducing species and increase the oxidative stress, which effectively killed the bacteria and inhibited subsequent biofilm formation. This paper provides a promising bactericidal nanocomposite with intrinsic properties for sterilization.

A CG@MXene nanocomposite-driven E-CRISPR biosensor for the rapid and sensitive detection of Salmonella Typhimurium in food

In this study, we developed a novel electrochemical biosensor based on CRISPR/Cas12a (E-CRISPR) for the rapid and sensitive detection of Salmonella Typhimurium (S. Typhimurium). The CRISPR/Cas12a system was applied to identify S. Typhimurium gene and induce signal changes in electrochemical measurement. The colloidal gold and MXene (CG@MXene) nanocomposites were synthesized and immobilized to improve the performance of the biosensor by decreasing the background noise. The formation process of CG@MXene was well characterized, and experiment conditions were fully optimized. Under the optimal conditions, the proposed E-CRISPR biosensor exhibited excellent sensitivity for S. Typhimurium, with a limit of detection (LOD) of 160 CFU/mL, and great specificity against other common foodborne pathogens. Furthermore, the feasibility of the E-CRISPR biosensor was evaluated by analyzing S. Typhimurium-spiked chicken samples, with a recovery rate ranging from 100.46% to 106.37%. In summary, this research proposed a novel E-CRISPR biosensor from a new perspective to detect S. Typhimurium which can be an alternative approach for bacterial detection in the food supply chain.

Toxicological, hepato-renal, endocrine disruption, oxidative stress and immunohistopathological responses of chitosan capped gold nanocomposite on Biomphalaria alexandrina snails

The present investigation aimed to synthesize chitosan‑gold nanocomposites (Ch-AuNPs) with gamma radiation, then to evaluate its toxic effect on the freshwater snails Biomphalaia alexandrina. Results showed that Ch-AuNPs is spherical shaped with average size 12 nm. It had a toxic effect against B. alexandrina snails with LC50 20.43 mg/l. Exposure of B. alexandrina snails to LC10 7.51 or LC25 13.63 mg/l of Ch-AuNPs, reduced the survival, reproductive and fecundity rates; total protein and albumin; both testosterone (T) and 17β Estradiol (E) levels; SOD and CAT activities of exposed snails while increased the activities of transaminases (AST & ALT), uric acid, creatinine, TAC and MDA levels compared to the control group. Results were supported by histopathological and immunohistopathological alterations of the digestive and hermaphrodite glands. In conclusion B. alexandrina could be used as a model to screen the negative impact of nanomaterials. Also, Ch-AuNPs could be used as a molluscicidal agent.

PCR- and label-free SARS-CoV-2 electrochemical immunosensor

Cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are still ubiquitously persistent, as new variants have emerged worldwide. Furthermore, severity and infectiousness are still not fully understood. Therefore, an imperative need still exists for more and better viral detection and diagnosis tools. Nanostructured electrochemical biosensors have shown outstanding features for highly sensitive Coronavirus disease 2019 (COVID-19) detection and diagnosis. This work reports on an electrochemical immunosensor based on nanocomposite-decorated screen-printed carbon electrodes (SPCE) for one-step detection of the spike protein by differential pulse voltammetry (DPV) without the need for enzymatic or PCR amplification. The SPCEs were decorated with graphene quantum dots (GQDs) coexisting with gold and platinum nanoparticle nanocomposite (GQDs@AuPt), improving their conductive properties and offering a high surface area and available carboxylic groups for the covalent immobilization of capture recombinant antibodies. As a result, the biosensor demonstrated high sensitivity and specificity in detecting spike protein by DPV in a linear range from 0.05 to 1.5 µg/mL and with a LOD of 60.14 ng/mL (0.78 nM). In addition, its potential application was demonstrated by detecting eleven positive concerning four negative nasopharyngeal swab samples from patients with COVID-19 and healthy individuals previously analyzed by the RT-PCR gold standard.

Development of a gliadin immunosensor incorporating gold nanourchin, molybdenum disulfide, titanium dioxide, and Nafion for enhanced electrochemiluminescence

Gluten contamination is a constant risk for people with celiac disease (CD), necessitating the development of specific and ultra-sensitive methods for detecting Gliadin. Here, we report the first use of a screen-printed gold electrode (SPGE) modified with a novel nanocomposite of gold nanourchin/molybdenum disulfide/titanium dioxide (AuNU/MoS2/TiO2) in Nafion to detect Gliadin using electrochemiluminescence (ECL). The nanocomposite enhanced ECL intensity by 5.6 times compared with the bare SPGE. The immunosensor had a linear detection range of 0.005–500 pg/mL, with a low limit of detection (LOD) of 0.005 pg/mL, the lowest among other Gliadin immunosensors. The immunosensor exhibited high selectivity, reproducibility, and stability, and demonstrated excellent recoveries (98.0%–104.9%) of Gliadin from real samples. The proposed immunosensor has the potential to provide a rapid and accurate gluten detection tool for the food industry, and to help protect CD patients against gluten exposure.

Gold nanoblackbodies-based multifunctional nanocomposite for multimodal cancer therapy

Multifunctional nanocomposites are of potential use to achieve complete tumor elimination and, thus, to avoid tumor recurrence. Herein, polydopamine (PDA)-based gold nanoblackbodies (AuNBs) loaded with indocyanine green (ICG) and Doxorubicin (DOX) termed as A-P-I-D nanocomposite were investigated for multimodal plasmonic photothermal-photodynamic-chemotherapy. Upon near-infrared (NIR) irradiation, A-P-I-D nanocomposite showed enhanced photothermal conversion efficiency of 69.2% compared to bare AuNBs (62.9%) due to the presence of ICG, along with ROS (1O2) generation as well as enhanced DOX release. On assessment of therapeutic effects on breast cancer (MCF-7) and melanoma (B16F10) cell lines, A-P-I-D nanocomposite showed significantly lower cell viabilities of 45.5% and 24% compared to 79.3% and 76.8% for AuNBs. Fluorescence images of stained cells revealed characteristic signs of apoptotic mode of cell death, with almost complete damage on A-P-I-D nanocomposite + NIR treated cells. Further, on evaluation of photothermal performance through breast tumor-tissue mimicking phantoms, A-P-I-D nanocomposite provided required thermal ablation temperatures within the tumor along with the potential for the elimination of residual cancerous cells through photodynamic therapy and chemotherapy. Overall, this study demonstrates that A-P-I-D nanocomposite + NIR provides better therapeutic outcome on cell lines and enhanced photothermal performance on breast tumor-tissue mimicking phantoms to be a promising agent for multimodal cancer therapy.

Gold nanoparticles modified reduced graphene oxide nanosheets based dual-quencher for highly sensitive detection of carcinoembryonic antigen

In the current scenario, the dominance of cancer is becoming a disastrous threat to mankind. Therefore, an advanced analytical approach is desired as the need of the hour for early diagnosis to curb the menace of cancer. In this context, the present work reports the development of nano surface energy transfer (NSET) based fluorescent immunosensor for carcinoembryonic antigen (CEA) detection utilizing protein functionalized graphene quantum dots (anti-CEA/amine-GQDs) and a nanocomposite of nanostructured gold and reduced graphene oxide (AuNPs@rGO) as energy donor-acceptor pair, respectively. The obtained AuNPs@rGO nanocomposite has been characterized by different advanced analytical techniques. The functionality of the biosensor depends on quenching the fluorescence of anti-CEA/amine-GQDs donor species by AuNPs@rGO acceptor species, followed by the gradual recovery of GQDs' fluorescence after CEA addition. The efficient energy transfer kinetics have been envisaged by utilizing the AuNPs@rGO nanocomposite as a dual-quencher nanoprobe that revealed improved energy transfer and quenching efficiency (∼62 %, 88 %) compared to AuNPs (∼43 %, 81 %) as a single quencher. Further, the developed biosensing platform successfully detected CEA biomarker with notable biosensing parameters, including a wider linear detection range (0.001–500 ng mL−1), fast response time (24 min), and a significantly low detection limit (0.35 pg mL−1).

Dual potential- and waveband-resolved electrochemiluminescence platform for simultaneous determination of three lung cancer biomarkers

The sensitive simultaneous detection of multiplex biomarkers is critical for the early cancer diagnosis. Herein, a dual potential- and waveband-resolved electrochemiluminescence (ECL) platform is reported for multiplexing immunoassay, using a rotating band-pass filter array for ECL spectrum discrimination. Three lung cancer biomarkers, neuron-specific enolase (NSE), carcinoembryonic antigen (CEA) and cytokeratin 19 fragment antigen (CYFRA21–1) were adopted as model analytes, with nanocomposites of gold nanoparticles/graphene oxide/N, N′- dicaproate sodium-3,4,9,10-perylenedicarboximide (AuNPs/GO/PDI), CdSe nanocrystals (NCs) and CdTe NCs as ECL tags, respectively. After forming corresponding sandwich-type immune-complexes on the surface of modified electrode via an one-pot immune-reaction, the intensities from the ECL tags of AuNPs/GO/PDI (Ep = −0.41∼ −0.46 V), CdSe NCs (λmax = 550 nm, Ep = −1.44∼ −1.46 V), and CdTe NCs (λmax=750 nm, Ep = –1.49 ∼ −1.51 V) in the signal antibody bio-conjugates were measured in a single cathodic potential scan run with K2S2O8 as the coreactant. The interference from the ECL of O2/S2O82- enhanced by the three ECL tags was corrected by the intensity at 649 nm in the waveband-resolved ECL mode. Under optimized conditions, NSE, CYFRA21–1 and CEA were simultaneously quantified with the detection limit values of 0.86, 2.6 and 0.53 fg mL−1, respectively.

An electrochemical biosensor for detecting DNA methylation based on AuNPs/rGO/g-C3N4 nanocomposite

DNA methylation as a ubiquitously regulation is closely associated with cell proliferation and differentiation. Growing data shows that aberrant methylation contributes to disease incidence, especially in tumorigenesis. The approach for identifying DNA methylation usually depends on treatment of sodium bisulfite, which is time-consuming and conversion-insufficient. Here, with a special biosensor, we establish an alternative approach for detecting DNA methylation. The biosensor is consisted of two parts, which are gold electrode and nanocomposite (AuNPs/rGO/g-C3N4). Nanocomposite was fabricated by three components, which are gold nanoparticles (AuNPs), reduced graphene oxide (rGO) and graphite carbon nitride (g-C3N4). For methylated DNA detection, the target DNA was captured by probe DNA immobilized on the gold electrode surface through thiolating process and subjected to hybrid with anti-methylated cytosine conjugated to nanocomposite. When the methylated cytosines in target DNA were recognized by anti-methylated cytosine, a change of electrochemical signals will be observed. With different size of target DNAs, the concentration and methylation level were tested. It is shown that in short size methylated DNA fragment, the linear range and LOD of concentration is 10−7M-10−15M and 0.74 fM respectively; in longer size methylated DNA, the linear range of methylation proportion and LOD of copy number is 3%–84% and 103 respectively. Also, this approach has a high sensitivity and specificity as well as anti-disturbing ability.

Mixed-Dimensional MXene Nanocomposites/Aramid Nanofibers-Based Flexible Pressure and Strain Sensor for Electronic Skin

The implementation of tactile functions in array sensors has created an urgent need for high-performance force sensors with both high linearity and sensitivity so as to ensure the uniformity and accuracy of acquisition of multiple sensing units in the array sensors. In addition, it still remains challenging to fabricate exquisite geometric constructions for integrating highly sensitive materials, extraordinary sensitivity, high stretchability, wide sensing range, and flexibility into a single type of pressure/strain sensor. Herein, a sensitive flexible sensor was fabricated that was composed of mixed-dimensional MXene-based nanocomposites as piezoresistive layers and Ecoflex layers as the encapsulation. The resultant sensors with MXene (Ti3C2Tx)-ANF (aramid nanofiber)-BP (black phosphorus)-gold (Au) nanocomposites exhibited excellent electrical conductivity, ultrahigh press sensitivity of 0.4986 kPa–1 (0–1 kPa), reliable linearity (R2 = 0.998), rapid response time of 12 ms, excellent durability over 4000 cycles, and ultrahigh tensile sensitivity of 9188.583. An 8 × 8 pixel electronic skin was fabricated by the as-prepared mixed-dimensional MXene-based sensors and tested in the identification of sliding movements and surface shape, and the good performance shows great potential applications in the fields of wearable devices, human–machine interaction, and robotics.

Red light-activable biotinylated copper(II) complex-functionalized gold nanocomposite (Biotin-Cu@AuNP) towards targeted photodynamic therapy

We report the synthesis and characterization of red-light activable gold nanoparticle functionalized with biotinylated copper(II) complex of general molecular formula, [Cu(L3)(L6)]-AuNPs (Biotin-Cu@AuNP), where L3 = N-(3-((E)-3,5-di-tert-butyl-2-hydroxybenzylideneamino)-4-hydroxyphenyl)-5-((3aS,4S,6aR)-2-oxo-hexahydro-1H-thieno[3,4-d]imidazol-4-yl)pentanamide, L6 = 5-(1,2-dithiolan-3-yl)-N-(1,10-phenanthrolin-5-yl)pentanamide, which was explored for their photophysical, theoretical and photo-cytotoxic potentials. The nanoconjugate exhibits differential uptake in biotin positive and biotin negative cancer cells as well as normal cells. The nanoconjugate also shows remarkable photodynamic activity against biotin positive A549 (IC50: 13 μg/mL in red light; >150 μg/mL in dark) and HaCaT (IC50: 23 μg/mL in red light; >150 μg/mL in dark) cells under red light (600–720 nm, 30 Jcm−2) irradiation, with significantly high photo-indices (PI>15). The nanoconjugate is less toxic to HEK293T (biotin negative) and HPL1D (normal) cells. Confocal microscopy confirms preferential mitochondrial and partly cytoplasmic localization of Biotin-Cu@AuNP in A549 cells. Several photo-physical and theoretical studies reveal the red light-assisted generation of singlet oxygen (1O2) (Ф (1O2) =0.68) as a reactive oxygen species (ROS) which results in remarkable oxidative stress and mitochondrial membrane damage, leading to caspase 3/7-dependent apoptosis of A549 cells. Overall, the nanocomposite (Biotin-Cu@AuNP) exhibiting red light-assisted targeted photodynamic activity has emerged as the ideal next generation PDT agents.

Enhancing the Efficiency of Doxorubicin -Conjugated with gold nanocomposites for Active Targeting and Laser Treatment for Human Esophagus Cancer Cells

Nanotechnology is being used in cancer treatment to deliver drugs to tumors, improve imaging, and detect cancer cells. Nanoparticles are being used to deliver drugs more effectively to tumors, while also reducing the side effects of the drugs. The current context shows the conceivable biomedical utility of gold nanoparticles (AuNPs) covered with doxorubicin (DOX) for double chemotherapy and photothermal therapy (PTT) of throat cancers (esophagus) in vitro. DOX as FDA-authorized anti-cancer drug was added to AuNPs to enhance the chemotherapy impact. The blended DOX - AuNPs showed exorbitant cytotoxicity at the cancer cells and strong light absorption for temperature expansion in vitro. In the wake of treating DOX– Au nanocomposites with inside the esophagus cell line, PTT-helped DOX-Au nanocomposites involved the fantastical cytotoxicity of the cell strains for 15 min after the laser treatment. Exceptionally cytotoxicity impact in esophagus cell line turned out to be more attractive due to specific light absorption with the aid of using the directed DOX-Au nanocomposites. Thusly, the proposed DOX-Au nanocomposites might be an ability nano-theranostic material for treating throat cancers. The gene expression levels withinside the esophagus cell line from every group with or without laser exposure have been compared individually with control group. Bax has been overexpressed in esophagus cell line organization post 15 min laser irradiation. Conversely, BCL-2 gene has been down regulated with the aid of using RT-PCR analysis post 15 min laser irradiation, while in comparison to control cell line.

Detection of Alpha Fetoprotein Based on AIEgen Nanosphere Labeled Aptamer Combined with Sandwich Structure of Magnetic Gold Nanocomposites.

As a biomarker, alpha-fetoprotein (AFP) is valuable for detecting some tumors in men, non-pregnant women, and children. However, the detection sensitivity in some methods needs to be improved. Therefore, developing a simple, reliable, and sensitive detection method for AFP is important for non-malignant diseases. An aptamer binding was developed based on aggregation-induced emission luminogen (AIEgen) nanosphere labeled with Fe3O4@MPTMS@AuNPs. AFP was detected with a sandwich structure of AuNPs magnetic composite particles. An aggregation-induced emission (AIE) molecule and polystyrene (PS) nanosphere complex were assembled, enhancing the fluorescence and improving the sensitivity of detection. The limit of detection (LOD) was at a given level of 1.429 pg/mL, which can best be achieved in serum samples. Finally, the results obtained showed the complex to be promising in practical applications.

Metal-carbon nanotube composite for wavelength-selective bolometer with improved characteristics

This work comprehensively discusses the utilization of a metal-multiwalled carbon nanotube (CNT) nanocomposite of gold (Au)/CNT for uncooled bolometric application synthesized by a simple rapid green synthesis technique. Enhanced light–matter interaction with the visible (532 nm) and near-infrared (1064 nm) radiations in the nanocomposite is utilized for achieving improved bolometric response at room temperature (RT, ∼300 K). A comparatively higher temperature coefficient of resistance of ∼−0.11%/K (improvement of ∼57%) was achieved in the Au/CNT nanocomposite bolometer (BM). Additionally, the composite BM demonstrated a dual (532 and 1064 nm) spectral selectively and enhanced sensitivity with respective large RT voltage responsivities of ∼11.70 ± 3.45 V/W and ∼503.54 ± 12.77 mV/W, as opposed to null response from the CNT BM. The current study, thus, demonstrates an important step toward designing high-performing CNT BMs for uncooled operation, with added functionality of wavelength-selectiveness.