Utilization of gold nanoparticles for the detection of squamous cell carcinoma of the tongue based on laser-induced fluorescence and diffuse reflectance characteristics: an in vitro study

Utilizing Laser-Induced Fluorescence to Evaluate the Efficiency of Carbon Dioxide and Diode Lasers in Dentin Sealing after Tooth Preparation: An in-vitro Study

Adhesive dentistry has made it feasible to design restorations with high aesthetic qualities and little invasiveness. However, the freshly cut dentin after the tooth preparation needs to be sealed to prevent its contaminations, bacterial leakage, and hypersensitivity. Consequently, the immediate dentin sealing (IDS) method has been advised. This study examines different dentinal tubule sealing methods via CO2 laser, diode laser (980-nm) and a two-step self-etch adhesive system applied directly to the fresh cut dentin preceding the placement of the provisional phase. The sealing efficiency of each laser and bond system was evaluated based on the laser-induced fluorescence (LIF) properties and image analysis by scanning electron microscopy. Moreover, the obtained LIF spectra were evaluated using partial least square progression. A two-step adhesive containing a high concentration of S-PRG fillers produced a thick layer that was not perfectly uniform at all sites due to uneven filler distribution in the bond with totally and partially closed dentinal tubules. However, the peaks of the LIF spectra dropped after applying laser because of its sealing effectiveness. Accordingly, CO2 and diode lasers have strong evidence in dentinal tubule sealing and a definitive treatment modality for dentinal hypersensitivity. Moreover, IDS with an adhesive system is superior in occluding dentinal tubules in a biomimetic manner based on its filler content and bioactive properties.

Anticancer effect and laser photostability of ternary graphene oxide/chitosan/silver nanocomposites on various cancer cell lines

Aims: The development of nanocomposites (NCs) of antitumor activity provides a new paradigm for fighting cancer. Here, a novel NC of green synthetic silver nanoparticles (AgNPs), graphene oxide (GO) and chitosan (Cs) NPs was developed. Materials & methods: The prepared GO/Cs/Ag NCs were analyzed using various techniques. Cytotoxicity of the NCs was evaluated against different cancer cell lines by Sulforhodamine B (SRB) assay. Results: GO/Cs/Ag NCs are novel and highly stable. UV-Vis showed two peaks at 227 and 469 nm, indicating the decoration of AgNPs on the surface of GO/Cs NPs. All tested cell lines were affected by GO/Cs NPs and GO/Cs/Ag NCs. Conclusion: The results indicate that GO/Cs/Ag NCs were present on tested cell lines and are a promising candidate for cancer therapy.

Influence of Tumor Volume on the Fluence Rate Within Human Breast Model Using Continuous-Wave Diffuse Optical Imaging: A Simulation Study

Objective: This article investigates the effect of varying breast tumor size on the fluence rate distribution within a breast model during the diffuse optical imaging procedure. Background: Early detection of breast cancer is of significant importance owing to its wide spread among women worldwide. Mastectomy surgery became very common due to the late detection of breast cancers by the conventional diagnostic methods such as X-ray mammography and magnetic resonance imaging. On the contrary, optical imaging techniques provide a safe and more sensitive methodology, which is suitable for the early detection criteria. Methods: The implementation was performed based on simulating multiple detectors placed on the outer surface of a human breast model to compute the optical fluence rate after probing the breast (normal and different tumor sizes) with laser irradiation. Different laser wavelengths ranging from the red to near-infrared rays spectral range were examined to determine the optimum fluence rate that shows the highest capability to differentiate between normal and cancerous breasts. A three-dimensional breast model was created using the COMSOL multiphysics package where the optical fluence rate was estimated based on the finite-element solution of the diffusion equation. Results: To evaluate the efficiency of the suggested technique for identifying cancers and discriminate them from normal breast at various wavelengths (600-1000 nm) and several tumor sizes. Conclusions: The obtained results reveal different fluence rate distributions in the breast with different radius tumors, especially at 600 nm due to the significant differences in the scattering coefficient between malignancies and healthy tissue.

Adaptive optics-based wavefront-enhanced laser-induced fluorescence (WELIF) for improved analytical performance

The current study proposes a novel optical approach based on an adaptive optics (AO) system to enhance the fluorescence intensity in the laser-induced fluorescence (LIF) technique. The proposed method, wavefront-enhanced LIF (WELIF), relies mainly on compensating for the aberrations arising from the excitation-laser wavefront. The AO system consists of an active correction element (deformable mirror (DM)) integrated with a Shack-Hartmann wavefront sensor (SHWFS). The overall system operates in a closed-loop configuration to compensate for the laser beam aberrations in real time. The performance of the interaction of the aberration-free excitation laser beam with solid samples, e.g., bone, leaf, polymer sheet, and with liquid samples, e.g., extra virgin olive oil (EVOO), showed a pronounced improvement in the fluorescence peak intensity. As an analytical application example, detailed WELIF measurements have been performed on five EVOO brands to demonstrate the validity of the new approach. Furthermore, the effectiveness of the proposed system was evaluated by measuring the enhancement factor, i.e., the ratio between the fluorescence peak intensity after aberration compensation (AC) relative to the initial peak intensity before aberration compensation (BC). The results reveal that the fluorescence peak intensities have been enhanced with ranges from 20% to 98% after compensation (AC). Besides, the results were statistically assessed based on the receiver operator characteristic (ROC) curve (84% sensitivity AC and 82% BC) and partial least squares regression, PLSR, with a 0.94 coefficient of determination AC compared to 0.90 BC.

Label-Free Optical Spectroscopy for Early Detection of Oral Cancer

Oral cancer is the 16th most common cancer worldwide. It commonly arises from painless white or red plaques within the oral cavity. Clinical outcome is highly related to the stage when diagnosed. However, early diagnosis is complex owing to the impracticality of biopsying every potentially premalignant intraoral lesion. Therefore, there is a need to develop a non-invasive cost-effective diagnostic technique to differentiate non-malignant and early-stage malignant lesions. Optical spectroscopy may provide an appropriate solution to facilitate early detection of these lesions. It has many advantages over traditional approaches including cost, speed, objectivity, sensitivity, painlessness, and ease-of use in clinical setting for real-time diagnosis. This review consists of a comprehensive overview of optical spectroscopy for oral cancer diagnosis, epidemiology, and recent improvements in this field for diagnostic purposes. It summarizes major developments in label-free optical spectroscopy, including Raman, fluorescence, and diffuse reflectance spectroscopy during recent years. Among the wide range of optical techniques available, we chose these three for this review because they have the ability to provide biochemical information and show great potential for real-time deep-tissue point-based in vivo analysis. This review also highlights the importance of saliva-based potential biomarkers for non-invasive early-stage diagnosis. It concludes with the discussion on the scope of development and future demands from a clinical point of view.

Optical Characterization of Biological Tissues Based on Fluorescence, Absorption, and Scattering Properties

Optical diagnostics methods are significantly appealing in biological applications since they are non-destructive, safe, and minimally invasive. Laser-induced fluorescence is a promising optical spectrochemical analytical technique widely employed for tissue classification through molecular analysis of the studied samples after excitation with appropriate short-wavelength laser light. On the other hand, diffuse optics techniques are used for tissue monitoring and differentiation based on their absorption and scattering characteristics in the red to the near-infrared spectra. Therefore, it is strongly foreseen to obtain promising results by combining these techniques. In the present work, tissues under different conditions (hydrated/dry skin and native/boiled adipose fat) were distinguished according to their fluorescence emission, absorption, and scattering properties. The selected tissues' optical absorption and scattering parameters were determined via Kubelka-Munk mathematical model according to the experimental tissue reflectance and transmittance measurements. Such measurements were obtained using an optical configuration of integrating sphere and spectrometer at different laser wavelengths (808, 830, and 980 nm). Moreover, the diffusion equation was solved for the fluence rate at the sample surface using the finite element method. Furthermore, the accuracy of the obtained spectroscopic measurements was evaluated using partial least squares regression statistical analysis with 0.87 and 0.89 R-squared values for skin and adipose fat, respectively.

Gold nanoparticles loaded chitosan encapsulate 6-mercaptopurine as a novel nanocomposite for chemo-photothermal therapy on breast cancer

Background

As a promising strategy to overcome the therapeutic disadvantages of 6-mercaptopurine (6MP), we proposed the encapsulation of 6MP in chitosan nanoparticles (CNPs) to form the 6MP-CNPs complexes. The encapsulation was followed by the loading of complexes on gold nanoparticles (AuNPs) to generate a novel 6MP-CNPs-AuNPs nanocomposite to facilitate the chemo-photothermal therapeutic effect.

Methods

CNPs were produced based on the ionic gelation method of tripolyphosphate (TPP). Moreover, 6MP-CNPs composite were prepared by the modified ionic gelation method and then loaded on AuNPs which were synthesized according to the standard wet chemical method using trisodium citrate as a reducing and capping agent. The synthesized nanocomposites were characterized by UV–VIS spectroscopy, dynamic light scattering, Fourier transform infrared spectroscopy, and transmission electron microscopy. The potential cytotoxicity of the prepared nanocomposites on MCF7 cell line was carried out using Sulphorhodamine-B (SRB) assay.

Results

Optimization of CNPs, 6MP-CNPs, and 6MP-CNPs-AuNPs revealed 130 ± 10, 200 ± 20, and 25 ± 5 nm particle size diameters with narrow size distributions and exhibited high stability with zeta potential 36.9 ± 4.11, 37, and 44.4 mV, respectively. The encapsulation efficiency of 6MP was found to be 57%. The cytotoxicity of 6MP-CNPs and 6MP-CNPs-AuNPs on breast cell line MCF7 was significantly increased and reached IC50 of 9.3 and 8.7 µM, respectively. The co-therapeutic effect of the nanocomposites resulted in an improvement of the therapeutic efficacy compared to the individual effect of chemo- and photothermal therapy. Irradiation of 6MP-CNPs and 6MP-CNPs-AuNPs with a diode laser (DPSS laser, 532 nm) was found to have more inhibition on cell viability with a decrease in IC50 to 5 and 4.4 µM, respectively.

Conclusion

The Chemo-Photothermal co-therapy treatment with novel prepared nanocomposite exhibits maximum therapeutic efficacy and limits the dosage-related side effects of 6MP.

Graphical Abstract

Enhanced cytotoxic effect of doxorubicin conjugated gold nanoparticles on breast cancer model

Background

The difficulty of achieving targeted drug delivery following administration of presently marketed anticancer therapeutics is still a concern. Metallic nanoparticles (NPs) appear to be promising in this regard. The present study focused on the use of gold nanoparticles (AuNPs) as a drug carrier for anticancer Doxorubicin (DOX) forming DOX–AuNPs nanocomposite. The anticancer effect of the prepared nanocomposite was evaluated using SRP essay on breast cancer cell line (MCF7) for different incubation times (24 h,48, and72hr). The prepared DOX–AuNPs nanocomposite was investigated by UV–visible spectroscopy, TEM, fluorescence spectroscopy, and FTIR spectroscopy.

Results

Our results showed that the prepared AuNPs and DOX–AuNPs nanocomposite have spherical and small size10 ± 2 nm and 12 ± 2 nm respectively. The potential cytotoxicity of the DOX-AuNPs nanocomposite on the MCF7 cell line was significantly increased compared to free DOX. The 20 µM DOX- AuNPs nanocomposite produced a similar decrease in cell survival as 80 µM free DOX.

Conclusion

Future work is in progress to investigate the positive effects of the prepared nanocomposite for chemo-photothermal combination treatment.