Concentration Of Gold Nanoparticles Research Articles

Insight into Sonodynamic Activities of Gold Nanoparticles with Different Morphologies

AbstractThe sonodynamic activities of gold nanoparticles (GNPs) with different morphologies, gold nanospheres (GNSs), gold nanoflowers (GNFs) and gold nanorods (GNRs), were explored by multi‐spectroscopic methods, in which the lesion degree of human serum albumin (HSA) was used as assessment index. The results revealed that three GNPs all had certain sonosensitivity but varying from different morphologies. It was also found that GNPs concentration and ultrasonic parameters were all critical influencing factors of sonodynamic injury HSA. Investigating the physical damage mechanism, the results indicated that the secondary and tertiary structure of HSA were compromised by ultrasound (US) combined with GNPs, so that the conformation of HSA was altered and the function was variously disturbed due to GNPs different morphologies. Studying the chemical damage mechanism, the results discovered that the yield of singlet oxygen (1O2) produced by GNPs with various morphologies combined with US was significant difference. Therefore, comprehensively analyzing the research results under different factors, the order of sonodynamic activities of GNPs was GNSs≈GNFs>GNRs. These findings may provide reference for the application of GNPs as sonosensitizers in sonodynamic therapy.

Surface enhanced Raman scattering in thin films: the importance of Raman analyte-plasmonic particle inverse geometry

Most of the successful applications of surface enhanced Raman scattering (SERS) involves placing the Raman analyte molecule over the SERS substrate. This conventional geometry of SERS does not work when the Raman analyte is in the form of a thin film. In this report, we experimentally demonstrate the importance of the rarely explored inverse geometry wherein a plasmonic particle is placed over an analyte thin film for SERS study. Initially, as a case study, the effect of size, concentration, and distribution of gold nanoparticles (AuNPs) on the SERS of Si wafer was performed. The AuNPs, prepared by optimized annealing of direct current sputtered Au, were characterized by scanning electron microscopy, atomic force microscopy, and UV-Visible spectrophotometry. Finally, as an application, SERS in inverse geometry was successfully performed with an electron-beam evaporated Si thin film. For the first time, a working formula has been proposed to determine the experimental enhancement factor (EEF) for the inverse geometry of SERS. The values of EEF were estimated to be 1526 and 3274 respectively for Si wafer and Si thin film for the similar distribution of AuNPs of average size 52 nm. This study provides an insight into the characterization of thin films.

Effect of Li2O composition and temperature on the ionic conductivity of lithium-borate-silicate glasses containing gold nanoparticles using electrochemical impedance spectroscopy

This research systematically investigates the conductivity properties of a lithium-borate-silicate glass containing varying amounts of Li2O (30 to 50 mol %) in the presence and absence of a fixed concentration of gold nanoparticles (0.05 M). Three techniques were used to characterize the glass material: Electrochemical Impedance Spectroscopy, X-ray diffraction, and Differential Scanning Calorimetry. Impedance spectra were recorded at temperatures of 100 °C, 140 °C, and 200 °C, and the results were analyzed qualitatively and quantitatively using models based on the equivalent circuit approach. It was observed that below a critical concentration of Li2O, namely 35 mol %, the conductivity behavior exhibits a single relaxation process. However, above the critical concentration, the materials present two relaxation processes associated with changes in morphology. Impedance measurements also evaluate the DC and AC conductivity properties of the glasses. Interestingly, regardless of the morphology, conduction in the glasses appears to be thermally activated, with the conduction mechanism being controlled by polaron hopping in a correlated barrier. There is no evidence suggesting that the gold nanoparticles play a significant role in determining the conduction properties of the glasses, at least within the concentration range studied here.

XMEA: A New Hybrid Diamond Multielectrode Array for the In Situ Assessment of the Radiation Dose Enhancement by Nanoparticles.

This work presents a novel multielectrode array (MEA) to quantitatively assess the dose enhancement factor (DEF) produced in a medium by embedded nanoparticles. The MEA has 16 nanocrystalline diamond electrodes (in a cell-culture well), and a single-crystal diamond divided into four quadrants for X-ray dosimetry. DEF was assessed in water solutions with up to a 1000 µg/mL concentration of silver, platinum, and gold nanoparticles. The X-ray detectors showed a linear response to radiation dose (r2 ≥ 0.9999). Overall, platinum and gold nanoparticles produced a dose enhancement in the medium (maximum of 1.9 and 3.1, respectively), while silver nanoparticles produced a shielding effect (maximum of 37%), lowering the dose in the medium. This work shows that the novel MEA can be a useful tool in the quantitative assessment of radiation dose enhancement due to nanoparticles. Together with its suitability for cells' exocytosis studies, it proves to be a highly versatile device for several applications.

Tailoring plasmonic sensing strategies for the rapid and sensitive detection of hypochlorite in swimming water samples.

Atunable plasmonic sensor has been developedby varying the dextran content in the initially synthesized dextran-gold nanoparticle (dAuNPs) solution. A colloidal nanogold solution (dAuNPs-Sol) was initially prepared using dextran and gold salt in alkaline media by a one-pot green synthetic route. The dAuNPs-Sol was combined with varying amounts of dextran (ranging from 0.01 to 30.01%) to create a tunable probe, along with different solid formats, including tablet (dAuNPs-Tab), powder (dAuNPs-Powder), and composite (dAuNPs-Comp). Both the liquid and solid phase plasmonic probes were characterized using UV-vis spectroscopy, transmission electron microscopy (TEM) dynamic light scattering (DLS), and zeta potential analysis. The impact of dextran content in the dAuNP solution is studied in terms of surface charge and hydrodynamic size. The influence of operational treatments used to achieve solid dAuNPs probes is also explored. All plasmonic probes were employed to detect a broad range of OCl¯ concentrations (ranging from µM to mM) in water through aggregation followed by calculating a lower and upper limit of detection (LLoD, ULoD) of the proposed colorimetric sensors. Results indicate that the most sensitive detection is achieved with a lower dextran content (0.01%), which exhibits an LLoD of 50µM. The dAuNPs-Sol sensor is selective and demonstrates real-world applicability, as confirmed by interference analysis and successful testing with various water samples. Additionally, it is found that a 20 × concentration of dextran-coated gold nanoparticles could be attained without any changes in the particle morphology. This concentration is achieved through a straightforward process that does not require the use of a centrifuge machine. This finding highlights the practicality and simplicity of the method, indicating its potential for scalable and cost-effective production of concentrated dAuNPs without compromising their structural integrity.

Reply to “Comment on Comparison of direct and indirect measures of transport efficiency in single particle inductively coupled plasma mass spectrometry” by H. Goenaga-Infante

This paper provides a rebuttal to the comments on our original research article entitled “Comparison of Direct and Indirect Measures of Transport Efficiency in Single Particle ICP-MS” recently published by Goenaga-Infante in Spectrochimica Acta Part B: Atomic Spectroscopy.The intent of our study is not to condemn the dynamic mass flow (DMF) method but rather to explore the use parameters under which it can and cannot be applied. As explained in the original paper, the goal of this study is to evaluate the ranges of use conditions under which measures of transport efficiency (TE) yield accurate and reproducible results for spICP-MS measurements of particle number concentration (PNC) and particle size (diameter, PS) of various gold nanoparticle (AuNP) suspensions. The evaluation was performed through a systematic comparison of three methods for the measurement of TE: the particle frequency (TEF), particle size (TES), and DMF methods using three types of spray chambers operated at cooled and ambient temperature conditions and employing different ICP-MS platforms. While we appreciate thorough critical and constructive comments on our paper, we strongly disagree that the conclusions and highlights are not supported by the content and findings about the features and benefits of the DMF method.The discussion of three additional independent studies in this field by other spICP-MS expert groups that have been published after the submission of our manuscript is included in this paper. While the DMF approach has been used in two interlaboratory comparisons for TE determination in spICP-MS measurements of PNC, only one laboratory, namely the laboratory led by Goenaga-Infante, provided results using the DMF method in both projects. A method cannot be considered validated if successful results have only been demonstrated within one laboratory.The paper by Goenaga-Infante claims that the main use of DMF, the assignment of a SI traceable PNC value to new commercial nanomaterials (NMs), has not been highlighted explicitly in our original paper. The advantages and disadvantages of the DMF, TES, and TEF methods to measure TE were presented throughout the manuscript and are clearly summarized in the conclusion. The assignment of PNC that is metrologically traceable to the SI implies that all known or suspected uncertainty components including bias are taken into account. Our research shows that under some use conditions, the biases inherent to the DMF method are not yet fully understood and cannot be accounted for. While Cuello-Nuñez et al. Journal of Analytical Atomic Spectrometry, 2020, DOI: https://doi.org/10.1039/c9ja00415g state that cooled conditions (2 °C) were used in their work, they do not define the level of bias that can be expected if different spray chamber temperatures are used, and they do not provide recommendations on the optimal use conditions that define the field of applicability of the DMF method. Furthermore, besides the use of a Scott-type spray chamber cooled to 2 °C, neither the composition material of the spray chamber nor the volume of the Scott-type spray chamber were specified. It is important to note that in our original research, fifteen of the nineteen experiments were conducted using a cooled spray chamber. Also, the four different ICP-MS platforms were used in the standard configuration and with additional spray chamber options encountered in common ICP-MS usage. The value of our work is that it extends the study of Cuello-Nuñez et al. to a wide variety of use conditions routinely encountered in spICP-MS analysis.

Analysis of antibiofilm activity gold and silver nanoparticles against uropathogenic Escherichia coli using confocal laser scanning microscopy

Infectious diseases, including urinary tract infections (UTIs), significantly impact global health, diminishing the quality of life and increasing clinical and economic burdens. Concerns arise due to the potential development of antimicrobial resistance (AMR) facilitated by biofilm formation. Nanotechnology, specifically silver and silver nanoparticles (1–100 nm), proves effective against bacterial strains, making them valuable in the biomedical field. Advances in microscopic imaging techniques, such as Confocal Laser Scanning Microscopy (CLSM), enhance our understanding of biofilms. This study aims to assess the effectiveness and optimal concentration of gold and silver nanoparticles in combating biofilms formed by uropathogenic Escherichia coli (UPEC) through CLSM analysis. The research comprises the following stages: rejuvenation of bacterial isolates and inoculum preparation, testing the anti-biofilm activity of gold and silver nanoparticles at concentrations of 25, 50, 75, and 100 ppm against UPEC using CLSM analysis. The findings reveal that both gold and silver nanoparticles exhibit anti-biofilm activity against UPEC at concentrations of 25, 50, 75, and 100 ppm, as confirmed by CLSM analysis. The optimal concentration for anti-biofilm activity of gold and silver nanoparticles against UPEC is identified as 100 ppm.

Utility of realistic microscopy-based cell models in simulation studies of nanoparticle-enhanced photon radiotherapy

To enhance the effect of radiation on the tumor without increasing the dose to the patient, the combination of high-Z nanoparticles with radiotherapy has been proposed. In this work, we investigate the effects of the physical parameters of nanoparticles (NPs) on the Dose Enhancement Factor (DEF), and on the Sensitive Enhancement Ratio (SER) by applying a version of the Linear Quadratic Model. A method for constructing voxelized realistic cell geometries in Monte Carlo simulations from confocal microscopy images was developed and applied to Gliobastoma Multiforme cell lines (U87 and U373). The comparison of simulations with realistic geometry and spherical geometry shows that there is significant impact on the survival curves obtained for the same irradiation conditions. Using this model, the DEF and the SER are determined as a function of the concentration, size and distribution of gold nanoparticles within the cell. For small NPs, d AuNP = 10 nm, no clear trend in the DEF and SER was observed when the number of NPs within the cell increases. Experimentally, the variable number of NPs measured inside the U373 cells (ranging between 1.48 × 105 and 1.19 × 106) also did not influence much the observed cell survival upon irradiation of the cells with a Co-60 source. The same lack of trend is obtained when the Au content in the cell is kept constant, 0.897 mg/g, but the size of the NPs is changed. However, if the number of NPs is kept constant (7.91 × 105) and the size changes, there is a critical diameter above which the dose effect increases significantly. Using the realistic geometries, it was verified that the key parameter for the DEF and the SER enhancement is the volume fraction of Au in the cell, with NP size being a more important parameter than the number of NPs.

Low Concentrations of Gold Nanoparticles as Electric Charge Carriers in Piezoelectric Cement-Based Materials.

Piezoelectric cement-based composites could serve to monitor the strain state of structural elements or act as self-powered materials in structural health monitoring (SHM) applications. The incorporation of piezoelectric materials as an active phase within cement matrices has presented a highly attractive avenue until today. However, their application is challenged by the low electrical conductivity of the hydrated cement matrix. Gold nanoparticles (Au NPs) possess substantial potential for elevating the free electrical charge within the matrix, increasing its electrical conductivity between the Au NPs and the cement matrix, thereby enhancing the piezoelectric response of the composite. In this sense, the objective of this study is to investigate the effects of incorporating low concentrations of gold nanoparticles (Au NPs) (442 and 658 ppm) on the electrical and piezoelectric properties of cement-based composites. Additionally, this study considers the effects of such properties when the material is cured under a constant electric field. Electrical impedance spectroscopy was used to evaluate the polarization resistance and piezoresistive properties of the material. Additionally, open-circuit potential measurements were taken alongside the application of mechanical loads to assess the piezoelectric activity of the composites. The findings revealed a notable decrease in the composite's total electrical resistance, reaching a value of 1.5 ± 0.2 kΩ, almost four times lower than the reference specimens. In the realm of piezoelectricity, the piezoelectric voltage parameter g33 exhibited a remarkable advancement, improving by a factor of 57 when compared to reference specimens. This significant enhancement can be attributed to both the concentration of Au NPs and the electrical curing process. In summary, the outcomes of this study underscore the feasibility of creating a highly electrically conductive cement-based matrix, using low concentrations of gold nanoparticles as electric charge carries, and indicate the possible piezoelectric behavior of the studied compposite.

Implementation of the Seeded Growth Method in Fabricating 3D‐Printed Nanocomposite Contact Lenses for Selective Transmission

Gold nanoparticles (GNPs) are useful materials that may be used in a variety of applications such as colorblindness management, drug delivery, and bacteria reduction. When incorporated with optical lenses, GNPs cause an absorption dip in the transmission spectra of the lenses. Out of the aforementioned medical applications, colorblindness management is the most benefited from such spectra absorption as it can potentially block problematic wavelengths that patients suffer from and hence manage their colorblindness, where color vision deficiency (CVD), also known as colorblindness, is a congenital ocular disorder that has no current cure, and patients suffering from it rely on wearable aids that enhance their color perception by filtering out the certain wavelengths. Herein, customized gold nanocomposite contact lenses are fabricated via additive manufacturing to filter selective transmission wavelengths in the range of 540 and 560 nm. To allow selective filtering, seed‐mediated synthesis of GNPs through nine growth steps is utilized to vary the GNPs’ size and plasmonic filtering properties. Thereafter, three contact lenses are fabricated with different GNPs concentrations and particle sizes. In the results of the study, it is indicated that the fabricated lenses can block certain wavelengths selectively while acquiring properties similar to commercially available eyewear.

Nanoparticle-mediated enhancement of plant cryopreservation: Cultivar-specific insights into morphogenesis and biochemical responses in Lamprocapnos spectabilis (L.) Fukuhara 'Gold Heart' and 'Valentine'.

The integration of nanoparticles (NPs) holds promising potential to bring substantial advancements to plant cryopreservation, a crucial technique in biodiversity conservation. To date, little attention has been focused on using nanoparticles in cryobiology research. This study aimed to assess the effectiveness of NPs in enhancing the efficiency of plant cryopreservation. In-vitro-derived shoot tips of bleeding heart (Lamprocapnos spectabilis (L.) Fukuhara) 'Gold Heart' and 'Valentine' were used as the plant material. The encapsulation-vitrification cryopreservation protocol included preculture, encapsulation, dehydration, storage in liquid nitrogen, rewarming, and recovery steps. Gold (AuNPs), silver (AgNPs), or zinc oxide (ZnONPs) nanoparticles were added at various concentrations either into the preculture medium or the protective bead matrix during encapsulation. The explant survival and further morphogenic and biochemical events were studied. Results showed that the impact of NPs on cryopreservation outcomes was cultivar-specific. In the 'Valentine' cultivar, incorporating 5 ppm AgNPs within the alginate bead matrix significantly improved cryopreservation efficiency by up to 12%. On the other hand, the 'Gold Heart' cultivar benefited from alginate supplementation with 5 ppm AgNPs and 5-15 ppm ZnONPs, leading to an over 28% increase in the survival rate of shoot tips. Interestingly, adding NPs to the preculture medium was less effective and sometimes counterproductive, despite promoting greater shoot proliferation and elongation in 'Valentine' explants compared to the control. Moreover, nanoparticles often induced oxidative stress (and enhanced the activity of APX, GPOX, and SOD enzymes), which in turn affected the biosynthesis of plant primary and secondary metabolites. It was found that supplementation of preculture medium with higher concentration (15 ppm) of gold, silver and zinc oxide nanoparticles stimulated the production of plant pigments, but in a cultivar-dependent matter. Our study confirmed the beneficial action of nanoparticles during cryopreservation of plant tissues.

Colorimetric detection of oral bacteria using functionalized gold nanoparticles as a plasmonic biosensor array.

Early detection of specific oral bacterial species would enable timely treatment and prevention of certain oral diseases. In this work, we investigated the sensitivity and specificity of functionalized gold nanoparticles for plasmonic sensing of oral bacteria. This approach is based on the aggregation of positively charged gold nanoparticles on the negatively charged bacteria surface and the corresponding localized surface plasmon resonance (LSPR) shift. Gold nanoparticles were synthesized in different sizes, shapes and functionalization. A biosensor array was developed consisting of spherical- and anisotropic-shaped (1-hexadecyl) trimethylammonium bromide (CTAB) and spherical mercaptoethylamine (MEA) gold nanoparticles. It was used to detect four oral bacterial species (Aggregatibacter actinomycetemcomitans, Actinomyces naeslundii, Porphyromonas gingivalis and Streptococcus oralis). The plasmonic response was measured and analysed using RGB and UV-vis absorbance values. Both methods successfully detected the individual bacterial species based on their unique responses to the biosensor array. We present an in-depth study relating the bacteria zeta potential and AuNP aggregation to plasmonic response. The sensitivity depends on multiple parameters, such as bacterial species and concentration as well as gold nanoparticle shape, concentration and functionalization.

Analysis of antibiofilm activity gold and silver nanoparticles against uropathogenic Escherichia coli using confocal laser scanning microscopy

Infectious diseases, including urinary tract infections (UTIs), significantly impact global health, diminishing the quality of life and increasing clinical and economic burdens. Concerns arise due to the potential development of antimicrobial resistance (AMR) facilitated by biofilm formation. Nanotechnology, specifically silver and silver nanoparticles (1–100 nm), proves effective against bacterial strains, making them valuable in the biomedical field. Advances in microscopic imaging techniques, such as Confocal Laser Scanning Microscopy (CLSM), enhance our understanding of biofilms. This study aims to assess the effectiveness and optimal concentration of gold and silver nanoparticles in combating biofilms formed by uropathogenic Escherichia coli (UPEC) through CLSM analysis. The research comprises the following stages: rejuvenation of bacterial isolates and inoculum preparation, testing the anti-biofilm activity of gold and silver nanoparticles at concentrations of 25, 50, 75, and 100 ppm against UPEC using CLSM analysis. The findings reveal that both gold and silver nanoparticles exhibit anti-biofilm activity against UPEC at concentrations of 25, 50, 75, and 100 ppm, as confirmed by CLSM analysis. The optimal concentration for anti-biofilm activity of gold and silver nanoparticles against UPEC is identified as 100 ppm.

Identifying factors controlling cellular uptake of gold nanoparticles by machine learning

There is strong interest to improve the therapeutic potential of gold nanoparticles (GNPs) while ensuring their safe development. The utility of GNPs in medicine requires a molecular-level understanding of how GNPs interact with biological systems. Despite considerable research efforts devoted to monitoring the internalisation of GNPs, there is still insufficient understanding of the factors responsible for the variability in GNP uptake in different cell types. Data-driven models are useful for identifying the sources of this variability. Here, we trained multiple machine learning models on 2077 data points for 193 individual nanoparticles from 59 independent studies to predict cellular uptake level of GNPs and compared different algorithms for their efficacies of prediction. The five ensemble learners (Xgboost, random forest, bootstrap aggregation, gradient boosting, light gradient boosting machine) made the best predictions of GNP uptake, accounting for 80–90% of the variance in the test data. The models identified particle size, zeta potential, GNP concentration and exposure duration as the most important drivers of cellular uptake. We expect this proof-of-concept study will foster the more effective use of accumulated cellular uptake data for GNPs and minimise any methodological bias in individual studies that may lead to under- or over-estimation of cellular internalisation rates.

Numerical modeling of skin tumors subjected to gold nanoparticle assisted laser-induced thermal therapy

Gold nanoparticle (GNP) laser-induced thermal therapy (LITT) for cancer tumor treatment, is a promising therapeutic procedure. It combines the laser deep penetration when operating in near-infrared band and the contrast agent high absorption at the considered wavelengths. Nevertheless, the treatment success is highly sensitive to the nanoparticles spatial/temporal distribution. Therefore, in this work we investigate the LITT effectiveness under conditions of non-uniform GNPs arrangement. In particular, the impact of gold nanoparticles diffusion mass transfer for different waiting periods between the GNPs injection and the treatment start was assessed. Moreover, the inoculated contrast agent concentration effect on the thermal therapy was also evaluated. Therefore, a numerical solver relying on foam-extend v.5.0 library was developed for modeling: (i) realistic intra-tumor injection. (ii) GNPs diffusion in the target area. (iii) thermal effects on skin tumors by means of LITT. It was found that a waiting period of about 24 h between the contrast agent inoculation and the treatment start is recommended. Lastly, injected GNPs concentration has to be also accurately calibrated to guarantee LITT success.

Efficacy of 15 nm Gold Nanoparticles for Image-Guided Gliosarcoma Radiotherapy

Targeted brain cancer treatments are sorely needed to improve long-term prognosis, particularly for gliosarcoma and glioblastoma patients. Gold nanoparticles (GNPs) have unique properties including high atomic number, biocompatibility, and small size for cancer cell internalization. GNPs are consequently an ideal candidate for improved cancer targeting using image-guided radiotherapy. This work investigated 15 nm AuroVistTM GNPs for image-guided gliosarcoma radiotherapy and identified optimum GNP concentrations. The GNPs were found to be 15–20 nm using optical surface plasmon resonance absorption, with a (41.3 ± 0.3) nm hydrodynamic diameter. Confocal imaging showed that 50–500 µg/mL of the GNPs was well-internalized into the 9L cells within 24–48 h. γ-H2AX assays showed that 50–500 µg/mL of the GNPs radiosensitized the 9L cells irradiated with 125 and 150 kVp X-rays. However, only 500 µg/mL of the GNPs produced significant long-term dose enhancement with 150 kVp X-rays (with a sensitization enhancement ratio at 10% survival of 1.43, and 1.13 with 50 µg/mL) using clonogenic assay. CT imaging of the GNPs in the 9L tumors in Fischer rats further showed that GNP concentrations above 500 µg/mL were required to distinguish the tumor from the brain, and the GNPs were detected 48 h after injection. These promising results indicate that the GNPs can be used for selective gliosarcoma treatment with image-guided X-ray radiotherapy at concentrations above 500 µg/mL.

Effect of Gold Nanoparticle Radiosensitization on DNA Damage Using a Quartz Tuning Fork Sensor.

The development of sensor technology enables the creation of DNA-based biosensors for biomedical applications. Herein, a quartz tuning fork (QTF) sensing system was employed as a transducer for biomedical applications to address indirect DNA damage associated with gold nanoparticles (GNPs) and enhance the effectiveness of low-dose gamma radiation in radiation therapy. The experiment included two stages, namely during and after irradiation exposure; shift frequencies (Δf) were measured for 20 min in each stage. During the irradiation stage, the QTF response to DNA damage was investigated in a deionized aqueous solution with and without 100 nm GNPs at different concentrations (5, 10, 15, and 20 µg/mL). Upon exposure to gamma radiation for 20 min at a dose rate of 2.4 µGy/min, the ratio of Δf/ΔT indicates increased fork displacement frequencies with or without GNPs. Additionally, DNA damage associated with high and low GNP concentrations was evaluated using the change in the resonance frequency of the QTF. The results indicate that GNPs at 15 and 10 µg/mL were associated with high damage-enhancement ratios, while saturation occurred at 20 µg/mL. At 15 µg/mL, significant radiotherapy enhancement occurred compared to that at 10 µg/mL at 10 min after exposure. In the post-irradiation stage, the frequency considerably differed between 15 and 10 µg/mL. Finally, these results significantly depart from the experimental predictions in the post-radiation stage. They exhibited no appreciable direct effect on DNA repair owing to the absence of an environment that promotes DNA repair following irradiation. However, these findings demonstrate the potential of enhancing damage by combining GNP-mediated radiation sensitization and biosensor technology. Thus, QTF is recommended as a reliable measure of DNA damage to investigate the dose enhancement effect at various GNP concentrations.

Conjugate dissipative radiative heating with thermal slipping and the entropy production on the thrust of MHD gold blood nanofluid with curvature effects

AbstractThis article analyzes the impact of conjugated dissipative radiative heat transfer with heat source/sink, thermal slip, and the transverse magnetic field on the behavior of the magnetohydrodynamic (MHD) peristaltic thrust containing ferromagnetic gold nanoparticles (AuNPs) with different shape factors through the non‐Newtionian blood flow within compliant walls tube. Entropy generation (EG) plays a prominent role in all aspects connected to thermodynamics and heat transfer aiding in the identification and reduction of system irreversibilities. The sources of irreversibility stem from dissipative friction inherent in fluid flow, the presence of a magnetic field, and the heat transfer process. The ferromagnetic gold nanoparticles (AuNPs) exhibit diverse shapes (bricks, cylinders, and platelets) and possess both magnetic and thermal attributes thereby enhancing the efficiency of heat transfer process. The peristaltic thrust drives the dynamic behavior of the gold blood nanofluid through a compliant tube. The tube walls are flexible and exhibit a curvature effects that can alter the dynamics of fluid flow. The effective Hamilton‐Crosser model is selected to express the thermal conductivity of the nanofluid. Gold blood nanofluids can be treated as incompressible, non‐Newtonian, and MHD fluid flow. The governing equations of the system are solved using the perturbation approach under the assumptions of low Reynolds numbers and long wavelength. Hybrid interactions of magnetic field, radiative heating, thermal slip, elastic wall properties, and gold nanoparticles shapes and concentrations are investigated within the gold blood nanofluid flow. The resulting graphs include the profiles of velocity, temperature distributions, EG, and irreversibility parameters under the influence of the above parameters. The findings reveal that the overall EG rises with increasing values of heat source intensity, Brinkman number, temperature difference factor, compliant wall curvature coefficient, and gold nanoparticles concentrations. Additionally, it is observed that an increase in magnetic flux strength results in the emergence of reversal flow patterns near the walls. This arises due to the augmented magnetic flux obstructing the peristaltic nanofluid flow leading to reduce streamwise velocity. Moreover, heightened magnetic flux strength causes temperature reduction for both thermal slip and non‐slip conditions. Generally, the presence of a thermal slipping parameter further enhances the distribution of temperature. In essence, the rationale and significance of this study primarily revolve around comprehending the interplay of these diverse factors with MHD peristaltic motion of gold blood nanofluid and EG. This not only furthers our theoretical understanding of complex systems but also has practical implications that can improve new technologies, processes, and medical applications. For example, in medical treatments like photothermal therapy (PPT), insights gained from this research can help in developing more effective and precise treatment methods. By understanding the impact of these factors on EG, new ways can be identified to minimize or manage system inefficiencies leading to more sustainable and optimized treatment processes. This research holds promise for application in cancer detection and treatment by employing a combination of PPT and magnetic hyperthermia. This entails dispersing AuNPs into the blood circulation through arteries and blood vessels and subsequently applying photothermal radiation and a magnetic field.

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.