Different Concentrations Of Gold Nanoparticles Research Articles

Improved in vitro biocompatibility and cytoplasmic localization of gold nanoparticles and graphene oxide nanosheets assessed using confocal microscopy

Nanomaterial-based delivery platforms have indeed revolutionized drug delivery systems in recent years. These platforms, which are based on various types of nanoparticles, offer several advantages over traditional drug delivery systems. Therefore, during this work, we synthesized gold nanoparticles (GNPs) and graphene oxide (GO) as representative nanomaterials and assessed their biocompatibility and cytoplasmic localization in vitro. Structural characterization of the prepared nanoparticles was performed by using different techniques. For instance, laser diffraction spectrometry using a Nano-ZS Zetasizer was used to determine the particles size, and Zeta potential. High-resolution transmission electron microscopy (HR-TEM) were utilized to evaluate Particle sizes and morphologies of the prepared nanoparticles. Additionally, the chemical structure of the prepared nanoparticles was assessed by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The effects of the different concentrations of GNPs and GO nanosheets on cell viability and proliferation were evaluated by WST-1 cell proliferation assays. Ultimately, in vitro studies were performed by confocal microscopy to characterize the cellular uptake of the prepared nanoparticles. The net results of this study suggest that both nanomaterials showed a cytoplasmic entry without penetrating the nucleus. They may be useful for slow drug release as well as photothermal and photodynamic therapy using a low-powered laser or IR radiation.

Self-referencing photothermal digital holographic microscope for characterization of low-loss liquids

Measurement of absorption coefficients of transparent samples is important for their characterization and identification; however, it is challenging to measure low values, e.g., 10−3–10−4 cm−1 with high accuracy. Here, we report a compact photothermal lateral shearing digital holographic device. It is based on the thermal lens effect and a common-path, self-referencing digital holographic microscope comprising a glass plate, probe beam, and a CMOS camera. The change in phase distribution caused by the temperature change due to light absorption is measured from the recorded holograms to extract the sample's absorbance and absorption coefficient. The feasibility of the proposed configuration is validated by the experimental results obtained with different concentrations of gold nanoparticles (AuNPs) in an aqueous solution. Determination of AuNPs concentration in the nM range is performed, and the obtained limits of detection and quantitation are 0.04 nM and 0.13, respectively. The calibration curve is linear at a low concentration range of 0.06–0.95 nM with 1% reproducibility. In addition, the method's versatility is demonstrated by measuring the absorption coefficient of low-loss solvents, such as ethanol and water. The determined absorption coefficients agree with the reported values, confirming that this method provides good spectrometric capabilities, such as high sensitivity and accuracy.

Orientation of capture antibodies on gold nanoparticles to improve the sensitivity of ELISA-based medical devices

The sensitivity of ELISA-based devices strongly depends on the right orientation of antibodies on the sensor surface. The aim of this work was to increase the analytical performance of a commercial ELISA-based medical device (VIDAS®), thanks to the specific orientation of antibodies on gold nanostructured disposables. For this purpose, fPSA VIDAS® assay was used as model and the disposable providing the antigen binding surface (SPR®) was functionalized with gold nanostructures coated with monovalent half-fragment antibodies (reduced IgG, rIgG). The functionalization of polystyrene SPRs® with gold nanostructures was achieved through a one-step incubation of gold dispersions in a mixture of non-toxic solvents. Five different concentrations of gold nanoparticles (NPs) were tested with a maximum fluorescence enhancement for NPs density around 3–8 *103 NPs/μm2 (752 ± 11 RFV vs 316 ± 5 RFV of bare SPRs®). The comparison of the dose-response curve obtained with commercial and gold coated-SPRs® revealed a significant improvement (p < 0.0001) of the analytical sensitivity of the VIDAS® system using nanostructured disposables. This improved version of SPRs® allows to distinguish small variations of fPSA concentrations opening the way to the application of this biomarker to other kinds of cancer as recently described in the literature.

Synthesis, characterization and electrochemical behavior for API 5L X70 carbon steel in 5% sulfamic acid medium using PVVH/PEMA blend filled with gold nanoparticles

In the present work, we synthesized the polymer blend of Poly (vinyl chloride-co-vinyl acetate-co-2-hydroxypropyl acrylate), and Poly (ethyl methacrylate) (PEMA) by solution casting method and then filled it with different concentrations of gold nanoparticles (Au-NPs). The present composite was employed as corrosion inhibitors for API 5L X70 carbon steel in 5% sulfamic acid solution by electrochemical methods such as potentiodynamic polarization (PP) and electrochemical impedance spectroscopy (EIS) techniques. The quantum chemical computations utilized by DFT process produced an acceptable theoretical interpretation for the adsorption and inhibition performance of the composite on the carbon steel surface. PP plots demonstrated that the examined samples act as a miscellaneous type inhibitor. With raising its concentrations, the inhibition productivity rises up to 91.3% in case of blend/ 3% Au-NPs as observed from the EIS results. The inhibition mechanism follows Langmuir adsorption isotherm. It was discussed as concerns the nanocomposite investigated adsorption on steel metal surface and confirmed using SEM. Bode plots exposed that, the total impedance elevated with raising examined polymer concentration and the constant addition to the phase angle move was clearly associated with the increasing of the examined polymer concentration adsorbed on carbon steel species. A significant agreement was attained among the quantum chemical variables (DFT and Mulliken atomic charges) and the experimental computations, indicating the efficiency of the nanocomposite to act as effective corrosion inhibitor.

Investigation on synthesis, structural and nonlinear optical responses of cadmium selenide coated with gold nanoparticles induced by femtosecond laser excitation

Nonlinear optical signal enhancement cannot be achieved by using semiconductor materials alone. Here, we show that the recently discovered nonlinear optical behavior of plasmonic nanoparticles and hybrid nanowires enables an enhanced nonlinear optical response. A synthesis, characterization, and nonlinear optical response of synthesized hybrid nanowires structures were studied. The growth of gold nanoparticles (Au NPs) onto cadmium selenide nanowires CdSe NWs with different concentrations of gold nanoparticles coating prepared via an impregnation technique. Au nanoparticles in the CdSe/Au nanowires were uniformly dispersed on the CdSe nanowire surface. The surface morphologies and the propagation manner of hybrid nanostructures were used for transmission electron microscopy (TEM) to study the optical properties of pure and hybrid nanostructures. Dark-field scattering microscopy was used to characterize single CdSe NW and confirm the coating of hybrid CdSe/Au nanowires and characterize the concentration effect of gold nanoparticles. The dark-field scattering spectrum (DFSS) reference to the surface plasmon resonance of nearer Au NPs was observed at ca. 800 nm. By making a comparison between a single cadmium selenide with and without gold nanoparticles coating, hybrid CdSe/Au nanowires exhibit sufficient quality to produce second-harmonic generation stimulated with a pulsed, linearly polarized pump-light from a femtosecond Ti-sapphire laser. The estimated improvement of the second-harmonic generation signal is about ~ 1.8 times, ~ 5.5 times, ~ 6.9 times for low, moderate and full coating of gold nanoparticles, which was mainly due to the high quality of synthesis techniques and good dispersion of gold nanoparticles on CdSe nanowires

COLOR PROPERTIES OF POLYMETHYLMETHACRYLATE MATERIAL INCORPORATED WITH GOLD NANOPARTICLES

The aim of this study was to investigate the influence of the addition of different concentrations of gold nanoparticles (AuNPs) on color parameters of nano-modified polymethyl methacrylate (PMMA) prosthesis base material as well as their mutual comparison. In our investigation, we used AuNPs produced by new technologies Ultrasonic Spray Pyrolysis (USP) method, from the precursor solution from Au (III)acetate. The addition of highly dispersed AuNP in PMMA (ProBase Hot, Ivoclar Vivadent, Liechtenstein), followed by the formation of nano-modified polymer composite is performed in a special way. Four groups of samples by uniform dimensions of 50 x 50 x 4 mm, and with different AuNPs concentration (PMMA-AuNP1 0,12%, PMMA-AuNP2 0,43%, PMMA-AuNP3 0,74% and control group) were performed.The color values show that L * (light) PMMA-AuNP1 sample is slightly lower than the base sample, while the PMMA-AuNP2 and PMMA-AuNP3 have a higher value. The basic sample has the highest C * value, so it is the most saturated (most colorful). The basic sample also has the highest value of b * (more yellow shades), while the other three samples have a lower b * value (more blue shades). Also, the color angle h is smaller than the basic one for all three samples (closer to the red color axis a +). Color changes in base resins were significantly affected by the addition of gold nanoparticles (p˃0.05). The color differences ΔE * are in the range from 2,6 – 4,9. The addition of AuNPs at the tested concentrations does not have a statistically significant effect on the change in material translucency of PMMA/AuNPs nanocomposite.

The effect of different concentrations of gold nanoparticles on growth performance, toxicopathological and immunological parameters of broiler chickens.

The present study aimed to evaluate what dosage of gold nanoparticles (GNPs) would improve growth performance, antioxidant levels and immune defense in broiler chickens. The experiment was carried out on 90 one-day-old mixbred Cobb chicks. The birds were allocated into three groups with three replicates. Group (1) kept as a negative control. Groups (2) and (3) received 5, 15 ppm GNPs via drinking water weekly for 35 days of chicks’ life. Blood samples were collected at 8, 15, 22 and 36 days for oxidative stress evaluations and immunological studies. The birds were slaughtered at the ages of 36 days and thymus, spleen, busa of Fabricius and liver were collected for histopathological description, RT-PCR analysis and DNA fragmentation assay. Our results confirmed that adding of 15ppm GNPs in drinking water were induced remarkable blood oxidative stress damage, histopathological alterations, up-regulation of IL-6, Nrf2 gene expression, and DNA fragmentation in the examined immune organs of the broiler chickens as well as a significant reduction in the antibody titer against Newcastle (ND) and avian influenza (AI) viruses were noticed. On the other hand, the group received 5 ppm GNPs noticed better growth performance with the enhancement of the final food conversion ratio (FCR) without any significant difference in the previous toxicological and immunological parameters compared with the control groups. We suggest that feeding of 5ppm GNPs could improve the antioxidant capacity, immunity and performance in poultry but further food quality assurance tests are required in the future to confirm its safety for people.

Gold nanoparticles incorporated into cryogel walls for efficient nitrophenol conversion

The past several decades have illustrated an enormous interest in noble metal nanoparticles for their superior catalytic activity, however, their industrial use is very restricted due to inefficient recovery leading to potential contamination of products and the environment. Immobilised nanoparticles illustrate promising results for scaling up processes, and can be successfully applied for various catalytic processes including waste industrial water treatment. The aim of the study was to design and study an easy and economically efficient green chemistry approach of preparation of macroporous material, with well distributed gold nanoparticles within the wall of cryogel. Ionic cryogels containing chitosan and tetrachloroaurate complex was reduced by 1.1.3.3-tetramethoxypropane, concurrently allowing chemical cross-linking of the polymer. A mechanism of reduction of noble gold complexes within the cryogel walls by tetramethoxypropane is also studied. Properties of the composite cryogels were evaluated using; differential scanning calorimetry, FT-IR, NMR, compression tests, SEM, TEM), Energy-dispersive X-ray spectroscopy and low temperature nitrogen adsorption. The catalytic activity of the in-situ synthesised gold nanoparticles was comprehensively studied using a model reduction reaction of 4-nitrophenol. Four different concentrations of gold nanoparticles within the cryogel structure were investigated. The turnover number and the turnover frequency parameters for cryogels containing four different concentrations of gold nanoparticles were calculated. The conversion degree of 4-nitrophenol to 4-aminophenol for cryogel containing the lowest of gold nanoparticles reached 96.8% at room temperature. The catalytic activity of incorporated gold nanoparticles for 4-nitrophenol conversion did not decline over 14 consequent testing cycles.

Effect of Ficus carica L. leaves extract loaded gold nanoparticles against cisplatin-induced acute kidney injury

BackgroundCisplatin (CisPt) is one of the most widely used and highly effective drugs for the treatment of various solid tumors, unfortunately acute kidney injury (AKI) is considered one of its side effects through several mechanisms including production of reactive oxygen species (ROS), pro-inflammatory and pro-fibrotic cytokines. Due to the poor effect of AKI therapy, the use of nanoparticles loaded with natural extracts for delivering to the kidney molecules are desirable. AimThis study aims to investigate the effectiveness of different concentrations of gold nanoparticles (Au-NPs) as a carrier for Ficus carica L. (Fig) leaves extract against CisPt induced AKI. MethodsSeventy male albino rats were used and divided into seven groups. After the experimental period, blood was withdrawn, serum was separated for determination of urea, creatinine, homocystein (Hcy) and folic acid while reduced glutathione (GSH), nitric oxide (NO), malondialdehyde (MDA), total antioxidant capacity (TAC) and hydroxyproline content (Hyp) were evaluated in kidney tissue homogenate. ResultsCisPt induced AKI in rats and results in a significant increase in the levels of serum urea, creatinine, Hcy and kidney Hyp, lipid peroxidation along with a significant reduction of kidney GSH, NO and TAC compared to the control rats. Treatment with Au-NPs and Fig extract particularly in a ratio of (3:2) respectively was shown to improve renal functions with efficient capacity in scavenging ROS and reduced AKI severity. ConclusionAu-NPs enhanced the anti-oxidative properties of the Fig extract in targeting kidney damaged tissue and reduced oxidative toxicity induced by CisPt.

Fabrication of Gold Nanoparticles of Different Sizes and its Interaction in Aquatic Phase

ABSTRACTThe generation of AuNPs was realized in presence of gold chloride (Au3+), and citrate solution as reducing agent. The production of AuNPs was proved by the color change in the solution; from yellow to red wine. Purified nanostructures synthesized at citrate/Au3+ molar ratio of 1.0/10.0 evidenced an absorption peak at 526 nm attributed to the localized surface Plasmon Resonance (LSPR) which suggested the formation of small gold nanoparticles (NPs). The decrease of citrate/Au3+ molar ratio at 1.0/3.0 provoked a growing of gold nanostructures, which was evidenced by a red shift in the SPR at 546nm. High Resolution Transmission Electron Microscopy technique evidenced the spherical form and sizes for both nanoparticles at the range 10-15 nm (small NPs) and 20-25 nm (big NPs), respectively. Electron Diffraction (ED) patterns for both sizes evidenced the (111), (200), (220), (311), and (222) reflections of face centered cubic (FCC) gold nanostructures. Studies of energy-dispersive X-ray Spectroscopy indicated peaks at 1.65, 2.12, 9.71, 11.58 and 13.38 keV for both nanostructures, which suggests the presence of gold into the crystalline structure of the nanoparticles. Interaction tests were carried out in presence of marine crustaceans and different concentrations of gold nanoparticles; including a control test. Both sizes evidenced to be toxic when the concentration and exposure time were increased.

Effect of gamma-irradiation on the structural, optical and electrical properties of PEO/starch blend containing different concentrations of gold nanoparticles

ABSTRACTBlend of polyethylene oxide (PEO)/starch (70/30 wt.%) filled with different amounts of gold nanoparticles (AuNPs) were prepared using the casting technique. X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) techniques were used to investigate the structure of polymeric samples before and after exposing to gamma irradiation at different times. XRD showed a gradual decrease in intensity of crystalline peaks with increasing the gamma dose denotes a decrease in the amount of crystalline phase in the films, while the FTIR measurement shows induced changes in chemical structure assigned to the AuNPs amount and irradiation times. The optical energy gap values (Eg) for unirradiated and irradiated samples were calculated and interpreted. The differential scanning calorimetry (DSC) which showed the miscibility between the two components of the blend. The electrical conductivity (σ) measurement was showed increased in electrical conductivity after exposure to the gamma dose. The gold nanoparticles were used as nanofiller to improve the structural and electrical properties of polymeric samples. The results showed the Gamma irradiation significantly effect on the structural and electrical properties of PEO/starch blend.

Enhanced efficiency of electric field tunability in photonic liquid crystal fibers doped with gold nanoparticles.

In this paper, we present our recent research results on light propagation in photonic crystal fibers (PCFs) infiltrated with a 6CHBT nematic liquid crystal (LC) doped with 2-nm gold nanoparticles (NPs) with a concentration in the range of 0.01 - 0.5% wt. Electro-optical response times and thermal tuning of the investigated samples have been studied in detail. We have observed up to ~80% decrease of rise times for different concentrations of gold NPs in the LC. Moreover, a significant reduction of the Fréedericksz threshold voltage (up to 60%) has been observed for samples with higher concentrations of 2-nm gold NPs in 6CHBT.

Spectral behavior of plasmon enhanced fluorescence in organic–inorganic perovskite quantum dot solutions

In this work, the fluorescence emission of hybrid lead bromide perovskite quantum dots is enhanced with the assistance of surface plasmon resonance of gold nanoparticles. Due to the high sensitivity of these quantum dots to an aqueous environment, a water-free synthesis method is chosen for the synthesis of gold nanoparticles. Spherical gold nanoparticles, with a diameter of 13 nm and a surface plasmon resonance peak at 527 nm, are synthesized using oleylamine. CH3NH3PbBr3 perovskite quantum dots, with two different sizes, are also synthesized that show fluorescence emission peaks at 507 and 534 nm. Different concentrations of gold nanoparticles are added to the quantum dots solutions. For quantum dots with a fluorescence peak at a higher energy than localized surface plasmon resonance (LSPR) energy, quenching of fluorescence is observed. However, for quantum dots with a fluorescence peak slightly red-shifted, compared to LSPR, the fluorescence is enhanced by the factor of 2. This fluorescence enhancement is resulted by adding nanoparticles with concentration of 140 μl. By further addition of nanoparticles, quenching of the emission is observed due to the reduction of the distances between the nanoparticles and the perovskite quantum dots.

Improvement of dose distribution in ocular brachytherapy with 125I seeds 20-mm COMS plaque followed to loading of choroidal tumor by gold nanoparticles.

Brachytherapy using removable ophthalmic plaques loaded with suitable small sealed radioactive seeds adjacent to the ocular's tumor has been widely used as an effective treatment. The aim of this study was to investigate the dose distribution in a modeled eyeball followed to loading of an ocular melanoma tumor with different concentrations of gold nanoparticles (GNPs) as dose enhancement agent by Monte Carlo (MC) calculations. The MC code of MCNPX 2.6.0 was used to modeling of COMS standard eye plaque loaded with 24 125I sources (6711 model) located on the sclera of modeled eyeball with detailed structures and materials. A choroidal melanoma tumor was simulated and loaded with different concentrations of spherical gold GNPs (50 nm in diameter). Dose enhancement factors (DEFs) of ocular components were calculated. The dosimetric properties of 125I source (6711 model) and dose distribution of COMS standard eye plaque were calculated successfully as recommended by TG-43U1; AAPM. Loading of tumor with GNPs increased dose to the tumor and decreased dose to the normal tissues; the DEF was increased up to 2.280 and 2.030 for tumor apex, while it was decreased to 0.760 and 0.892 for macula and for gold-tumor mixture and nanolattice distributions, respectively. Loading the choroidal tumor volume with GNPs improves the dose distribution by increasing dose to the tumor and decreasing dose to the health components in ocular brachytherapy with 125I seeds 20-mm COMS plaque.

Thermo- and electro-optical properties of photonic liquid crystal fibers doped with gold nanoparticles.

Thermo- and electro-optical properties of a photonic liquid crystal fiber (PLCF) enhanced by the use of dopants have been investigated. A 6CHBT nematic liquid crystal was doped with four different concentrations of gold nanoparticles (NPs), 0.1, 0.3, 0.5 and 1.0 wt %, for direct comparison of the influence of the dopant on the properties of the PLCF. The thermo-optical effects of the liquid crystal doped with gold NPs were compared in three setups, an LC cell, a microcapillary and within the PLCF, to determine if the observed responses to external factors are caused by the properties of the infiltration material or due to the setup configuration. The results obtained indicated that with increasing NP doping a significant reduction of the rise time under an external electric field occurs with a simultaneous decrease in the nematic–isotropic phase transition temperature, thus improving the thermo- and electro-optical properties of the PLCF.

Structural, optical, morphological and thermal properties of PEO/PVP blend containing different concentrations of biosynthesized Au nanoparticles

Casting technique was used for preparation of polyethylene oxide (PEO)/polyvinyl pyrrolidone (PVP) (70/30wt.%) films filled with different concentrations of gold nanoparticles (Au NPs). X-ray diffraction (XRD) pattern proved the semi-crystalline nature of the pristine and filled polymer blend. Fourier transform infrared (FT-IR) and Ultraviolet/Visible (UV/Vis.) analyses were used to retrace the structural and optical changes with increasing Au content. UV/Vis. analysis spectroscopy was utilized to calculate the optical properties such as optical energy gap Eg, refractive index n and Urbach energy Eu for blend/Au nanocomposite films. Scanning electron micrograph (SEM) suggested the dependence of morphological structure on filling level and the surface morphology changed from rough to smooth. Transmission electron microscope (TEM) micrographs showed that the size of Au NPs was increased with continuous filling in PEO/PVP. Thermogravimetric analysis (TGA) was performed to investigate the thermal stability for nanocomposite films.

Improved Margins Detection of Regions Enriched with Gold Nanoparticles inside Biological Phantom.

Utilizing the surface plasmon resonance (SPR) effect of gold nanoparticles (GNPs) enables their use as contrast agents in a variety of biomedical applications for diagnostics and treatment. These applications use both the very strong scattering and absorption properties of the GNPs due to their SPR effects. Most imaging methods use the light-scattering properties of the GNPs. However, the illumination source is in the same wavelength of the GNPs’ scattering wavelength, leading to background noise caused by light scattering from the tissue. In this paper we present a method to improve border detection of regions enriched with GNPs aiming for the real-time application of complete tumor resection by utilizing the absorption of specially targeted GNPs using photothermal imaging. Phantoms containing different concentrations of GNPs were irradiated with a continuous-wave laser and measured with a thermal imaging camera which detected the temperature field of the irradiated phantoms. By modulating the laser illumination, and use of a simple post processing, the border location was identified at an accuracy of better than 0.5 mm even when the surrounding area got heated. This work is a continuation of our previous research.

Dual Function of Gold Nanoparticles in Synergism with Mitoxantrone and Microwave Hyperthermia Against Melanoma Cells

Background:This study was performed to evaluate any synergetic effects of mitoxantrone (MX) and gold nanoparticles (GNPs) as dual therapeutic approach, along with microwave (MW) hyperthermia for melanoma cancer.Methods:Various tests were performed on the DFW melanoma cell line in the presence of MX and different concentrations of GNPs, with and without MW irradiation. MTT [3-(4,5-dimethylthiazol–2-yl)-2,5-iphenyltetrazolium bromide] assays were conducted to evaluate the effectiveness of the used therapeutic methods in terms of cell survival. Relative lethal synergism (RLS) was calculated as the ratio of cell death following hyperthermia in the presence of a treatment agent to that after applying hyperthermia in the absence of the same treatment agent.Results:Results showed MX and GNPs under MW irradiation to provide maximum cell death (P < 0.001 compared to the other groups). The mean RLS for MW hyperthermia along with the MX-GNP combination was 4.14, whereas in the absence of GNP the value for MX chemotherapy was 0.94.Conclusion:MX chemotherapy in the presence of different concentrations of GNP did not alter cell survival as compared to in its absence.

Spectroscopic and thermal analysis of polyacrylamide/chitosan (PAM/CS) blend loaded by gold nanoparticles

Different concentrations of gold nanoparticles (Au NPs) have been doped to polyacrylamide/chitosan (PAM/CS) blend by casting method to demonstrate the effect of nano particles as a doped on the structural, morphological and thermal behavior for PAM/CS blend. Nanocomposite films were characterized before and after addition of the gold. The FT-IR measurement shows some changes in the chemical structure with increase of the gold nanoparticles. The X-ray diffraction indicated that degree of crystallinity for PAM/CS blend was decreased after adding the nano-gold. Transmission electron microscope (TEM) images of the samples contain the gold nanoparticles in PAM/CS matrices showed that the spherical particle has a size range nearly from 5 to 30nm. The parameters of kinetic thermodynamic like activation energies, enthalpy, Gibbs free energy and entropy were calculated from the thermogravimetric (TG) curves. The thermal data irregularly decrease with increasing of gold nanoparticles. TG analysis showed the thermal stability of nanocomposites films after addition of Au NPs was enhanced.

Gold nanoparticles in combination with megavoltage radiation energy increased radiosensitization and apoptosis in colon cancer HT-29 cells

Purpose: Gold nanoparticles (GNP) act as a radiosensitizer in radiation therapy. However, recent studies have shown contradictory evidence in terms of radiosensitization in the presence of GNP combined with X-ray megavoltage energy (MV) on different cell types. In this study, the effect of GNP on radiosensitization enhancement of HT-29 human colorectal cancer cells at MV X-ray energy was evaluated.Materials and methods: The cytotoxicity and radiosensitization of GNP were evaluated in HT-29 human colorectal cancer cells by MTS-assay and multiple MTS-assay, respectively. Cellular uptake was assayed using graphite furnace atomic absorption spectrometry (GFAAS). Apoptosis and cell cycle progression were determined by an Annexin V-FITC/propidium iodide (PI) kit and PI/RNase solution with flow cytometry, respectively.Results: Results showed that the cell viability of the HT-29 cells was not influenced by exposure to different concentrations of GNP (10–100 μM). GNP alone did not affect the cell cycle progression and apoptosis. In contrast, GNP, in combination with radiation (9 MV), induced more apoptosis. The interaction of GNP with MV energy resulted in a significant radiosensitization enhancement compared with irradiation alone.Conclusion: It was concluded that GNP may work as bio-inert material on HT-29 cancer cells and their enhancement of radiosensitization may be due to increase in the absorbed irradiation dose.