Abstract:To monitor the progress and prevent the spread of the COVID-19 pandemic in real time and outside laboratories, it is essential to develop effective tests that can ensure rapid, selective, and reliable diagnosis of infected persons in different environments. Key in this regard is the lateral flow immunoassays (LFIAs) that can detect the presence of the SARS-CoV-2 virus quickly, with the aid of nanoparticles (NPs) and specific proteins. We report the use of gold (Au) NPs AuNPs synthesised from a gold(iii) chlori… Show more
“…As another case, Au NPs were synthesized through ultrasonic spray pyrolysis (USP) and lyophilization (freeze-drying) process and were stabilized by polyvinylpyrrolidone (PVP) [ 18 ]. After lading a certain amount of antigen SARS-CoV-2 (“spike” protein S1), aggregation and also redshift of LSPR were observed in the UV-visible spectrum.…”
Severe respiratory syndrome COVID-19 (SARS-CoV-2) outbreak has became the most important global health issue, and simultaneous efforts to fast and low-cost diagnosis of this virus were performed by researchers. One of the most usual tests was colorimetric methods based on the change of color of gold nanoparticles in the presence of viral antibodies, antigens, and other biological agents. This spectral change can be due to the aggregation of the particles or the shift of localized surface plasmon resonance due to the electrical interactions of surface agents. It is known that surface agents could easily shift the absorption peak of metallic nanocolloids which is attributed to the localized surface plasmon resonance. Experimental diagnosis assays for colorimetric detection of SARS-CoV-2 using Au NPs were reviewed, and the shift of absorption peak was studied from the viewpoint of numerical analysis. Using the numerical method, the refractive index and real and imaginary parts of the effective relative permittivity of the viral biological shell around Au NPs were obtained. This model gives a quantitative description of colorimetric assays of the detection of SARS-CoV-2 using Au NPs.
“…As another case, Au NPs were synthesized through ultrasonic spray pyrolysis (USP) and lyophilization (freeze-drying) process and were stabilized by polyvinylpyrrolidone (PVP) [ 18 ]. After lading a certain amount of antigen SARS-CoV-2 (“spike” protein S1), aggregation and also redshift of LSPR were observed in the UV-visible spectrum.…”
Severe respiratory syndrome COVID-19 (SARS-CoV-2) outbreak has became the most important global health issue, and simultaneous efforts to fast and low-cost diagnosis of this virus were performed by researchers. One of the most usual tests was colorimetric methods based on the change of color of gold nanoparticles in the presence of viral antibodies, antigens, and other biological agents. This spectral change can be due to the aggregation of the particles or the shift of localized surface plasmon resonance due to the electrical interactions of surface agents. It is known that surface agents could easily shift the absorption peak of metallic nanocolloids which is attributed to the localized surface plasmon resonance. Experimental diagnosis assays for colorimetric detection of SARS-CoV-2 using Au NPs were reviewed, and the shift of absorption peak was studied from the viewpoint of numerical analysis. Using the numerical method, the refractive index and real and imaginary parts of the effective relative permittivity of the viral biological shell around Au NPs were obtained. This model gives a quantitative description of colorimetric assays of the detection of SARS-CoV-2 using Au NPs.
“…4 c, d. Zeta potential is considered as an indicator of the stability of nanoparticles. This negative value of zeta potential is due to the presence of three deprotonated anionic carboxyl groups of citrate ions which verify the repulsive interaction between nanoparticles and aim to prevent the agglomeration of AuNPs [ 26 , 27 ]. Fig.…”
Multi-drug resistance (MDR) in addition to the damage to non-malignant normal cells are the most difficult in cancer treatment. Drug delivery and Plasmonic photothermal therapy based on the use of resonant metallic nanoparticles have developed as promising techniques to destroy cancer cells selectively. In the present work, gold nanoparticles (AuNPs) were synthesized using trisodium citrate. The prepared AuNPs have a small size of 14 ± 4 nm and exhibit high stability with Zeta potential − 18 mV, AuNPs showed higher photothermal heating efficiency compared to irradiation with a 532 nm laser alone on the breast cancer cell line (MCF-7). Treatment of MCF-7 cells with 0.125 mM AuNPs coupled with laser irradiation for 6 min was found to significantly reduce (34%) the cell viability compared to 5% obtained with AuNPs in the same concentration and 26% with laser irradiation for 6 min without AuNPs. Moreover, the prepared AuNPs were used as an anticancer drug carrier for Doxorubicin (Dox), upon loading Dox to AuNPs there was a slight increase in the particle size to 16 ± 2 nm, FT-IR spectroscopic results showing the binding of Dox to AuNPs was through the –NH group. The potential cytotoxicity of the DOX@AuNPs nanocomposite was significantly increased compared to free DOX on the MCF7 cell line with a decrease in IC50. All these results suggested the potential use of AuNPs as therapeutic photothermal agents and drug carriers in cancer therapy.
“…It is noted that size estimated from TEM microscopy is smaller than that obtained from the dynamic light scattering method. This can be explained in terms of the lack of the hydration shell during the TEM particle size determination [ 25 , 26 ]. Moreover, in the FTIR spectrum of the utilized NPs (Fig.…”
Squamous cell carcinoma is a very common type of oral cancer that affects the health of people with an unacceptably high mortality rate attributed to the difficulties in detecting the disease at an early stage. Therefore, effective techniques for early diagnosis and effective therapy of oral cancer are necessary. In the present study, we exploit the ability of gold nanoparticles (AuNPs) to undergo coupled surface plasmon resonance when closely spaced to improve diagnosing squamous cell carcinoma of the tongue. The prepared AuNPs are characterized by UV–VIS spectroscopy, dynamic light scattering, Fourier transform infrared spectroscopy, and transmission electron microscopy. The size of the prepared AuNPs is 12 ± 2 nm with narrow size distributions and exhibited high stability with a zeta potential of − 16.5 mV. The light fluorescence of the normal and cancer cells is recorded before and after NP addition using a spectrometer upon excitation by 405-nm laser irradiation. Furthermore, the light reflectance of the examined samples is measured at different laser wavelengths (red to NIR region). The obtained results show that the cancer cells mixed with AuNPs produce a higher fluorescence peak at 489.2 nm than the cancer cells without AuNPs. Moreover, the optical diffuse reflectance analyses reveal that the addition of AuNPs enhances cancer detection especially at the 635-nm irradiation with sensitivity (94%), specificity (87%), and overall accuracy (91%).
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