Chitosan-capped Gold Nanoparticles Research Articles

Naked-Eye Detection of LAMP-Produced Nucleic Acids in Saliva Using Chitosan-Capped AuNPs in a Single-Tube Assay.

Loop-mediated isothermal amplification (LAMP) is a low-technology molecular assay that is highly adaptable to point-of-care (POC) applications. However, achieving sensitive naked-eye detection of the amplified target in a crude sample is challenging. Herein, we report a simple yet highly efficient and sensitive methodology for the colorimetric visualization of a single target copy in saliva using chitosan-capped gold nanoparticles (Chit-AuNPs) synthesized via a green chemistry approach. The presence or absence of free Chit in the Chit-AuNPs solution was shown to affect LAMP colorimetric detection oppositely: the observed stabilization in the negative samples and aggregation in the positive samples in the presence of free Chit were reversed in the case of neat Chit-AuNPs. The mechanism of the two assays was investigated and attributed to electrostatic and depletion effects exerted between the Chit-AuNPs, free Chit, and the solution components. The developed contamination-free, one-tube assay successfully amplified and detected down to 1-5 cfu of Salmonella and 10 copies of SARS-CoV-2 per reaction (25 μL) used, respectively, as model DNA and RNA targets in the presence of 20% saliva, making the method suitable for POC applications. Compared to the commonly used pH-sensitive dyes, Chit-AuNPs are shown to have an enhanced sensitivity toward naked-eye colorimetric observation owing to the direct detection of DNA amplicons. Thus, this is a simple, highly sensitive, fast, and versatile naked-eye detection methodology that could be coupled to any LAMP or RT-LAMP assay, avoiding the need of using complicated sample pretreatments and/or AuNPs long and laborious functionalization processes.

Green Synthesis of Chitosan-Capped Gold Nanoparticles Using Salvia officinalis Extract: Biochemical Characterization and Antimicrobial and Cytotoxic Activities

Green Synthesis of Chitosan-Capped Gold Nanoparticles Using Salvia officinalis Extract: Biochemical Characterization and Antimicrobial and Cytotoxic Activities

Resonance Rayleigh scattering technique-using chitosan-capped gold nanoparticles, approaches spectrofluorimetric method for determination of Bentazone residual in water samples

In this study, a resonance Rayleigh scattering technique-based sensing method for detecting Bentazone residual in water samples has been developed. This technique was carried out using chitosan-capped gold nanoparticles with a spectrofluorimetric method. Experimental results revealed that the developed method could allow the detection of Bentazone residual as low as a concentration of 0.02 ng mL−1 within 50-sec time. Overall results confirmed the very low detection limit for measuring the Bentazone. The chitosan-capped gold nanoparticles as an excellent sensor were applied to measure and analyze Bentazone in water samples.

Chitosan capped-gold nanoparticles as skin penetration enhancer for small molecules: A study in porcine skin

Skin is considered one of the most convenient sites for drug administration. The present study evaluated the effect of gold nanoparticles stabilized by chitosan (CS-AuNPs) and citrate ions (Ci-AuNPs) on skin permeation of sodium fluorescein (NaFI) and rhodamine b base (RhB) as small model hydrophilic and lipophilic permeants, respectively. CS-AuNPs and Ci-AuNPs were characterized by transmitted electron microscopy (TEM) and dynamic light scattering (DLS). Skin permeation was investigated using porcine skin with diffusion cells and confocal laser scanning microscopy (CLSM). The CS-AuNPs and Ci-AuNPs were spherical-shaped nanosized particles (38.4 ± 0.7 and 32.2 ± 0.7 nm, respectively). The zeta potential of CS-AuNPs was positive (+30.7 ± 1.2 mV) whereas that of Ci-AuNPs was negative (-60.2 ± 0.4 mV). The skin permeation study revealed that CS-AuNPs could enhance the permeation of NaFI with enhancement ratio (ER) of 38.2 ± 7.5, and the effect was superior to that of Ci-AuNPs. CLSM visualization suggested that skin permeation was enhanced by improving the delivery through the transepidermal pathway. However, the permeability of RhB, a lipophilic molecule, was not significantly affected by CS-AuNPs and Ci-AuNPs. Moreover, CS-AuNPs had no cytotoxic toward human skin fibroblast cells. Therefore, CS-AuNPs are a promising skin permeation enhancer of small polar compounds.

Chitosan-Mediated Environment-Friendly Synthesis of Gold Nanoparticles with Enhanced Photonic Reactivity

We developed a very simple, efficient and environment-friendly synthesis method for the manufacturing of high-performance chitosan-capped gold nanoparticles that could be used for biosensing applications. Gold nanoparticles were prepared through the spontaneous reduction of chloroauric acid by chitosan, which was used as both a reducing and a stabilizing agent. The samples were heated to a temperature of 60 °C under ultrasonic conditions. The composite system made of chitosan as a matrix and gold nanoparticles demonstrated a high stability in an aqueous buffer solution. The nanoparticles displayed an enhancement in photonic performance compared with the same property of individual components as a result of surface plasmon resonance at the interface between the structural phases of the hybrid structure. The enhanced photonic reactivity of the hybrid nanostructure may offer new insights for future possible biosensing applications.

Sustainable Synthesis of FITC Chitosan-Capped Gold Nanoparticles for Biomedical Applications

The quest for novel nanoscale materials for different applications necessitates that they are easy to obtain and have excellent physical properties and low toxicity. Moreover, considering the ongoing environmental impact of noxious chemical waste products, it is important to adopt eco-friendly approaches for nanoparticle synthesis. In this work, a natural polymer (medium molecular weight chitosan) derived from chitin was employed as a reducing agent to obtain gold nanoparticles (AuNPs) with a chitosan shell (AuNPs@CS) by a microwave oven. The chitosan is economically viable and cost-competitive in the market showing also nontoxic behavior in the environment and living organisms. The synthesized AuNPs@CS-FITC NPs were fully characterized by spectroscopic and microscopic characterization techniques. The size distribution of NPs was about 15 nm, which is a suitable dimension to use in biomedical applications due to their high tissue penetration, great circulation in blood, and optimal clearance as well as low toxicity. The prepared polymer-capped NPs were further functionalized with a fluorescent molecule, i.e., Fluorescein-5-isothiocyanate (FITC), to perform imaging in the cell. The results highlighted the goodness of the synthesis procedure, as well as the high internalization rate that resulted in an optimal fluorescence intensity. Thus, this work presents a good sustainable/green approach-mediated polymer nanocomposite for various applications in the field of diagnostic imaging.

Synthesis of Carboxymethyl Chitosan-Capped Gold Nanoparticles by Gamma Irradiation with Novel Potential Applications as Antioxidant, Hepatoprotective, and Anticancer Substance

Gold nanoparticles capped by carboxymethyl chitosan (AuNPs/CM-chitosan) with particle sizes of 5.2–7.3 nm were successfully synthesized by the γ-irradiation of Au3+ solutions. Their characteristics were analysed by transmission electron microscope images, powder X-ray diffraction patterns, UV-visible spectroscopy, and Fourier transform infrared spectra. The antioxidant activity of AuNP/CM-chitosan was time dependent and much higher than that of ascorbic acid at the same concentration. On the other hand, the results of tail vein injection of AuNP/CM-chitosan in mice indicated that this product was not toxic to mice and that AuNPs were mainly distributed in liver tissue, at approximately 77.5%, 6 h after injection. The hepatoprotective activity of AuNP/CM-chitosan was also tested in acetaminophen-induced hepatotoxic mice by oral administration at daily doses of 0.5–2 mg/head. The results indicated that compared to the control, supplementation with 2 mg of AuNPs/head strongly reduced the aspartate aminotransferase and alanine aminotransferase indexes in the blood of the tested mice by approximately 66.5 and 69.3%, respectively. Furthermore, the MTT (3[4,5 dimetylthiazol-2-yl]-2,5-diphenyltetrazol bromide) assay on a liver cancer cell line (HepG2) clearly confirmed strong anticancer activity on HepG2 cells treated with 0.05–0.5 mM AuNPs and the tested cells did not survive after treatment with 0.5 mM AuNPs, while the growth of the normal cell line (L929) has no significant effect at the same treated concentration of AuNPs. The AuNP/CM-chitosan in the present study was synthesized by the γ-irradiation method without using any toxic-reducing chemical and stabilized in a natural biocompatible polymer. The strong antioxidant, hepatoprotective, and anticancer effects of this product may be supported to be used in the biomedical field.

A label free nanosensing platform for the detection of cervical cancer through analysis of ultratrace DNA hybridization

BackgroundCervical cancer is a major health problem caused by human papillomavirus (HPV) infection which affects more than 500,000 women every year worldwide. Majority of the cases occur in less developed countries since there are lack of availability of effective screening methods for diagnosis. Therefore, a fast, accurate and early detection platform is developed for HPV detection. The current study describes a sensitive, specific, easy and a cost-effective label free DNA based electrochemical biosensor for HPV-16 detection. MethodologyDetection of HPV-16 is performed by an electrochemical platform coated with chitosan capped gold nanoparticles (ccAuNPs). These nanoparticles were characterized using Ultraviolet–visible (UV–vis) analysis, Fourier Transfer Infrared Ray analysis (FT-IR) and Transmission Electron Microscope (TEM). The probe DNA (PDNA) was then immobilized onto the nanoparticle modified electrode and hybridized with target DNA (TDNA). The electrochemical analysis was done at each step of modification using cyclic voltammetry (CV) and square wave voltammetry (SWV). ResultsThe biosensor responds to TDNA concentration range from 1 pM to 1 μM and the limit of detection is 1 pM with the sensitivity of 0.39 mA pM−1. This proposed biosensor achieved good performance of the PDNA/ccAuNPs modified ITO electrode. ConclusionsThe results illustrate that the developed nanotechnology-based electrochemical DNA biosensor provides very low detection limit in picomolar level. It also exhibited excellent selectivity and stability, which is important for potential applications in the onsite analysis of HPV-16 and in medical diagnosis.

A potential antibiofilm, antimicrobial and anticancer activities of chitosan capped gold nanoparticles prepared by γ–irradiation

ABSTRACT Recently, nanotherapy has been considered a promising and rapidly evolving field to combat cancer. Both gold nanoparticles and chitosan are interesting materials with biological and antitumor properties. The present study aimed to synthesise chitosan/gold nanocomposites (Cs/Au) using gamma irradiation technique and to study their anticancer, antibiofilm and antimicrobial activities. The synthesized Cs/Au nanocomposites were characterized using various analytical tools such as UV-vis, XRD, and TEM. UV-vis absorption spectra exhibited a surface plasmon resonance (SPR) peak at 525 nm that confirming the successful synthesis of colloidal AuNPs. The TEM image demonstrates well-dispersed spherical shaped Au nanoparticles. The cytotoxic activity of Cs/Au nanocomposites was examined against HepG-2 and CACO-2 cell lines in comparison to free chitosan using neutral red assay test. The Cs/Au nanocomposites inhibited the proliferation of cancer cells more than chitosan. Moreover, the prepared Cs/Au nanocomposites showed antibacterial and antibiofilm activities encouraging its potential candidature for biomedical and pharmaceutical purposes.

Rapid synthesis of chitosan-capped gold nanoparticles for analytical application and facile recovery of gold from laboratory waste

Chitosan-capped gold nanoparticles (CS-AuNPs) were synthesized via a rapid method by exposing 0.75 mL of 10 mM HAuCl4 and 5 mL of 0.1% w/v chitosan solution to microwave irradiation at 125 °C for 40 s. The resulting red colloidal solution contained monodispersed, spherical, and stable CS-AuNPs with a mean diameter of 17.8 nm and showed the maximum absorption peak at 520 nm. Owing to the positively charged surface, CS-AuNPs were applied to the assay of the polyanionic compound disodium edetate based on the aggregation-induced red-to-blue color change of the particles and the measurement of increased absorbance at 670 nm. The assay was accurate and precise; its results were comparable to those obtained from the titrimetric reference method. Moreover, gold was shown to be easily recovered from CS-AuNPs through alkaline-induced precipitation followed by acid treatment and heating, which provides a facile and efficient means for treatment of laboratory waste.

Impact of citrate- and chitosan-capped gold nanoparticles on the liver of Swiss albino mice: Histological and cyto-genotoxic study

The present study aimed to disclose the histological alterations and cyto-genotoxic potential induced by citrate- and chitosan-capped AuNPs on liver of adult Swiss albino mice. Animals were randomly divided into 8 groups. The first two groups were intraperitoneally (i.p) injected with physiological saline once and left for 10 days and every other day for 21 days, respectively, and kept as negative control groups. While the third and fourth groups were injected i.p with a single dose of 2 mg/kg of citrate- and chitosan-capped AuNPs, respectively, and left for 10 days. The fifth and sixth groups were injected i.p every other day for 21 days with 200 µg/kg of citrate- and chitosan-capped AuNPs, respectively. Animals of the seventh and eighth groups were injected i.p with 50 mg/kg cyclophosphamide once and left for 10 days and with 20 mg/kg cyclophosphamide every other day for 21 days, respectively. The livers of mice were dissected and processed for microscopic examination and for analyzing the expression of inflammation-related genes using RT-PCR. In addition, bone marrow samples were taken to investigate the mitotic index and the chromosomal aberrations. The present study showed various degrees of structural changes in the liver of animals received AuNPs. Such changes were more prominent in animals treated with a single dose of AuNPs, particularly with citrate-capped AuNPs as compared to chitosan-capped AuNPs. Furthermore, genotoxic analysis did not reveal any genotoxicity for AuNPs with both coats. Therefore, chitosan-capped AuNPs were less hepatotoxic than citrate-capped ones. However, it has not been proven that AuNPs are genotoxic by both coats.

LSPR based optical fiber sensor with chitosan capped gold nanoparticles on BSA for trace detection of Hg (II) in water, soil and food samples

Mercury is a diversely bioaccumulating heavy metal pollutant toxic to all life forms. In this work, an optical biosensor has been developed and calibrated for universal detection and quantification of mercuric ions, in the range 0.1–540 parts per billion, in biological and environmental samples. Chitosan capped gold nanoparticles on bovine serum albumin are proposed as an ultrasensitive plasmonic mercury receptor on U-bend optical fiber platform. The sensor was calibrated and tested with tap water, sewage contaminated water, marine water, long lived sea fish tissue, fossil fuel fly ash contaminated soil and vegetable samples. The sensor performance was validated with real samples inherently containing mercury. Overall standard error of less than 15% and a coefficient of variation less than 12% (n = 3) was found across all samples, indicating good fitness for diverse usage. Experimentally determined limit of detection of mercuric ions was 0.1 parts per billion in tap water (twenty times lesser than the Environment protection agency limit of 2 parts per billion in drinking water) and 0.2 parts per billion in sea fish and vegetable samples with negligible cross sensitivity towards other metal ions.

Chitosan-capped gold nanoparticles for indicating temperature abuse in frozen stored products

The present study aimed to optimize the conditions for the synthesis of gold nanoparticles (AuNP) using chitosan and to assess its effectiveness as temperature threshold indication for frozen storage conditions. Chitosan concentration of 0.25% and temperature of 90 °C for 15 min was optimum for synthesizing AuNP. The maximum absorbance (λmax) was observed at 530 and 540 nm for 0.125% and 0.25% chitosan, respectively, indicating shifting of peak toward longer wavelengths (red shift) with increasing chitosan concentration indicating larger AuNPs. A prominent absorption peak at 1367 cm−1 by Fourier transform-infrared (FTIR) spectrum corresponding to C−C stretching of the glucosamine group of chitosan indicates the chitosan capping on the AuNP. Higher peak intensity and a peak shift toward shorter wavelength were observed for AuNPs exposed to frozen temperature abused conditions. Distinctly clear visible color variation from cherry red to gray indicates its application as temperature abuse indicator in frozen products.

Multifunctional Chitosan-Capped Gold Nanoparticles for enhanced cancer chemo-radiotherapy: An invitro study

Over the last decade, chemo-radiotherapy represented a well-established paradigm for cancer treatment. Developing new strategies to promote the therapeutic efficacy while reducing toxic side effects of chemo-radiotherapy is a main research objective in cancer therapy. A promising new oncological strategy for enhancing chemo-radiotherapy against cancer involves the utilization of multifunctional nanoparticles (nanocarriers and radiosensitizers). In this work, Chitosan-Capped Gold Nanoparticles (CS-GNPs) were synthesized and loaded with an anticancer agent, Doxorubicin (CS-GNPs-DOX). The prepared multifunctional nano-formulation acted as nano-radiosensitizer, in addition to being an intrinsic drug delivery system allowing efficient loading and targeting of chemotherapeutics. The therapeutic efficacy of CS-GNPs-DOX was studied by treating breast cancer cells (MCF-7) with CS-GNPs-DOX accompanied by different doses of X-rays (0.5, 1 and 3 Gy) and assessing the cytotoxic effect via neutral red cell viability assay. Further assessment of the therapeutic efficacy was conducted using flowcytometry to measure the induction of apoptosis, while neutral comet assay was carried out to check DNA double strand breaks. Results showed that CS-GNPs-DOX could enhance the chemo-radiotherapeutic effect by significantly decreasing cancer cells viability with increasing DNA double strand breaks and inducing cell necrosis even at a very low radiation dose (0.5 Gy). Interestingly, the developed multifunctional CS-GNPs-DOX provided a synergistic regimen for cancer treatment that effectively delivered DOX to tumor cells and enhanced the radiosensitization activity, thus minimizing conventional radio-therapeutic required doses. Accordingly, CS-GNPs-DOX represents a promising multifunctional nanoparticle for enhancing breast cancer chemo-radiotherapy.

Development, optimization, and in vitro characterization of dasatinib-loaded PEG functionalized chitosan capped gold nanoparticles using Box–Behnken experimental design

Objective: The purpose of this research study was to develop, optimize, and characterize dasatinib loaded polyethylene glycol (PEG) stabilized chitosan capped gold nanoparticles (DSB-PEG-Ch-GNPs).Methods: Gold (III) chloride hydrate was reduced with chitosan and the resulting nanoparticles were coated with thiol-terminated PEG and loaded with dasatinib (DSB). Plackett–Burman design (PBD) followed by Box–Behnken experimental design (BBD) were employed to optimize the process parameters. Polynomial equations, contour, and 3D response surface plots were generated to relate the factors and responses. The optimized DSB-PEG-Ch-GNPs were characterized by FTIR, XRD, HR-SEM, EDX, TEM, SAED, AFM, DLS, and ZP.Results: The results of the optimized DSB-PEG-Ch-GNPs showed particle size (PS) of 24.39 ± 1.82 nm, apparent drug content (ADC) of 72.06 ± 0.86%, and zeta potential (ZP) of −13.91 ± 1.21 mV. The responses observed and the predicted values of the optimized process were found to be close. The shape and surface morphology studies showed that the resulting DSB-PEG-Ch-GNPs were spherical and smooth. The stability and in vitro drug release studies confirmed that the optimized formulation was stable at different conditions of storage and exhibited a sustained drug release of the drug of up to 76% in 48 h and followed Korsmeyer–Peppas release kinetic model.Conclusions: A process for preparing gold nanoparticles using chitosan, anchoring PEG to the particle surface, and entrapping dasatinib in the chitosan-PEG surface corona was optimized.

Targeted drug delivery of Sunitinib Malate to tumor blood vessels by cRGD-chiotosan-gold nanoparticles

The unique characteristics of tumor vasculature represent an attractive strategy for targeted delivery of antitumor and antiangiogenic agents to the tumor. The purpose of this study was to prepare c(RGDfK) labeled chitosan capped gold nanoparticles [cRGD(CS-Au) NPs] as a carrier for selective intracellular delivery of Sunitinib Malate (STB) to the tumor vasculature. cRGD(CS-Au) NPs was formed by electrostatic interaction between cationic CS and anionic AuNPs. cRGD modified CS-Au NPs had a spherical shape with a narrow size distribution. The entrapment efficiency of sunitinib molecule was found to be 45.2%±2.05. Confocal microscopy showed enhanced and selective uptake of cRGD(CS-Au) NPs into MCF-7 and HUVEC cells compared with non-targeted CS-Au NPs. Our results suggest that it may be possible to use cRGD(CS-Au) NPs as a carrier for delivery of anticancer drugs, genes and biomolecules for inhibiting tumor vasculature.

Synthesis and ultraviolet visible spectroscopy studies of chitosan capped gold nanoparticles and their reactions with analytes.

Gold nanoparticles (AuNPs) had been synthesized with various molarities and weights of reducing agent, monosodium glutamate (MSG), and stabilizer chitosan, respectively. The significance of chitosan as stabilizer was distinguished through transmission electron microscopy (TEM) images and UV-Vis absorption spectra in which the interparticles distance increases whilst retaining the surface plasmon resonance (SPR) characteristics peak. The most stable AuNPs occurred for composition with the lowest (1 g) weight of chitosan. AuNPs capped with chitosan size stayed small after 1 month aging compared to bare AuNPs. The ability of chitosan capped AuNPs to uptake analyte was studied by employing amorphous carbon nanotubes (α-CNT), copper oxide (Cu2O), and zinc sulphate (ZnSO4) as the target material. The absorption spectra showed dramatic intensity increased and red shifted once the analyte was added to the chitosan capped AuNPs.

Chitosan-capped gold nanoparticles for selective and colorimetric sensing of heparin

In this contribution, novel chitosan-stabilized gold nanoparticles (AuNPs) were prepared by mixing chitosan with citrate-reductive AuNPs under appropriate conditions. The as-prepared chitosan-stabilized AuNPs were positively charged and highly stably dispersed in aqueous solution. They exhibited weak resonance light scattering (RLS) intensity and a wine red color. In addition, the chitosan-stabilized AuNPs were successfully utilized as novel sensitive probes for the detection of heparin for the first time. It was found that the addition of heparin induced a strong increase of RLS intensity for AuNPs and the color change from red to blue. The increase in RLS intensity and the color change of chitosan-stabilized AuNPs caused by heparin allowed the sensitive detection of heparin in the range of 0.2–60 μM (~6.7 U/mL). The detection limit for heparin is 0.8 μM at a signal-to-noise ratio of 3. The present sensor for heparin detection possessed a low detection limit and wide linear range. Additionally, the proposed method was also applied to the detection of heparin in biological media with satisfactory results.Electronic supplementary materialThe online version of this article (doi:10.1007/s11051-013-1930-9) contains supplementary material, which is available to authorized users.

Effectively catalytic decomposition of acetaldehydes in spirits by using chitosan-capped gold nanoparticles

As shown in the literature, chitosan (Ch) can react easily with acetaldehydes to form Schiff bases with high yields at room temperature. Therefore, in this work, we report an innovative idea to prepare nanocomposites (NCs) of Ch-capped gold NPs (NPs) for effectively catalytic decomposition of acetaldehyde in spirits. Ch of NCs can easily catch acetaldehydes in spirits. Thus the caught acetaldehydes were therefore concentrated on NCs. Subsequently, the concentrated acetaldehydes were catalytically decomposed on catalysts of Au NPs in Ch/Au NCs. Experimental results indicate that the acetaldehyde was significantly decomposed by ca. 40 % in 120 ppm acetaldehyde-containing white spirits by adding 0.05 ppm Ch-capped Au NPs after three days. This efficiency for catalytic decomposition of acetaldehyde is a marked increase by ca. 200 % of magnitude, as compared with that based on commercial Au NPs with similar sizes at the same Au concentration. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Attenuated effects of chitosan-capped gold nanoparticles on LPS-induced toxicity in laboratory rats

The impact of nanoparticles in medicine and biology has increased rapidly in recent years. Gold nanoparticles (AuNP) have advantageous properties such as chemical stability, high electron density and affinity to biomolecules. However, the effects of AuNP on human body after repeated administration are still unclear. Therefore, the purpose of the present study was to evaluate the effects of gold-11.68nm (AuNP1, 9.8μg) and gold-22.22nm (AuNP2, 19.7μg) nanoparticles capped with chitosan on brain and liver tissue reactivity in male Wistar rats exposed to lipopolysaccharide (LPS from Escherichia coli serotype 0111:B4, 250μg) upon 8 daily sessions of intraperitoneal administration. Our results suggest that the smaller size of chitosan-capped AuNP shows the protective effects against LPS-induced toxicity, suggesting a very high potential for biomedical applications.