Laser Light Research Articles

Rotational magic conditions for ultracold molecules in the presence of Raman and Rayleigh scattering

Molecules have vibrational, rotational, spin-orbit and hyperfine degrees of freedom or quantum states, each of which responds in a unique fashion to external electromagnetic radiation. The control over superpositions of these quantum states is key to coherent manipulation of molecules. For example, the better the coherence time the longer quantum simulations can last. The important quantity for controlling an ultracold molecule with laser light is its complex-valued molecular dynamic polarizability. Its real part determines the tweezer or trapping potential as felt by the molecule, while its imaginary part limits the coherence time. Here, our study shows that efficient trapping of a molecule in its vibrational ground state can be achieved by selecting a laser frequency with a detuning on the order of tens of GHz relative to an electric-dipole-forbidden molecular transition. Close proximity to this nearly forbidden transition allows to create a sufficiently deep trapping potential for multiple rotational states without sacrificing coherence times among these states from Raman and Rayleigh scattering. In fact, we demonstrate that magic trapping conditions for multiple rotational states of the ultracold 23Na87Rb polar molecule can be created.

Preliminary Study of Resonance Systems States in Surface Plasmon Resonance Systems

Abstract Resonance between light and collective electrons is known as Surface Plasmon Resonance or SPR. The development of SPR-based sensors can generate the use of a Kretschmann configuration prism. Otto configuration dielectric medium between prism and gold thin film. For the Kretschmann configuration, a gold thin film between the prism and dielectric medium. So, this research focuses on the use of the Kretschmann configuration in the SPR system because the setup of the half-cylindrical prism is less complicated than using the Otto configuration. In this research, we compare the reflectance of an uncoated half-cylindrical prism and a half-cylindrical prism coated with a gold thin film to see the resonance effect. The beam reflected by the back surface of the prism was detected using a photodiode sensor (OPT-101, Texas Instruments). The photodiode sensor is connected to Arduino Uno, and the voltage reading results are processed with Arduino Ide software. Adjusting the He-Ne laser light’s angle of incidence and the prism’s angle of impact 30° – 50°. The experimental results show that the TIR (total internal reflection) phenomenon occurs in half-cylindrical prisms without a gold coating. Meanwhile, in the half-cylindrical prism coated with gold, a resonance phenomenon can be seen, this case, at a particular angle of incidence, can be detected through a reduction in the beam’s intensity of the reflected light. The photodiode sensor detects a decrease in voltage value, which indicates an intensity decrease, which was originally 4.34 volts to 2.52 volts when the incident angle of the light beam was 45°.

Quantifying Volumetric Scattering Bias in ICESat‐2 and Operation IceBridge Altimetry Over Greenland Firn and Aged Snow

AbstractThe Ice, Cloud, and Land Elevation Satellite‐2 (ICESat‐2) mission has collected surface elevation measurements for over 5 years. ICESat‐2 carries an instrument that emits laser light at 532 nm, and ice and snow absorb weakly at this wavelength. Previous modeling studies found that melting snow could induce significant bias to altimetry signals, but there is no formal assessment on ICESat‐2 acquisitions during the melting season. We performed two case studies over the Greenland Ice Sheet to quantify bias in ICESat‐2 signals over snow: one to validate Airborne Topographic Mapper (ATM) data against Next Generation Airborne Visible/Infrared Imaging Spectrometer (AVIRIS‐NG) grain sizes, and a second to estimate ICESat‐2 bias relative to ATM. We used snow optical grain sizes derived from ATM and AVIRIS‐NG to attribute altimetry bias to snowpack properties. For the first case study, the mean and standard deviation of optical grain sizes were 340 ± 65 µm (AVIRIS‐NG) and 670 ± 420 µm (ATM). A mean altimetry bias of 4.81 ± 1.76 cm was found for ATM, with larger biases linked to increases in grain size. In the second case study, we found a mean grain size of 910 ± 381 µm and biases of 6.42 ± 1.77 cm (ICESat‐2) and 9.82 ± 0.97 cm (ATM). The grain sizes and densities needed to recreate biases with a model are uncommon in nature, so we propose that additional surface attributes must be considered to characterize ICESat‐2 bias over snow. The altimetry biases are within the accuracy requirements of the ICESat‐2 mission, but we cannot rule out more significant errors over coarse‐grained snow.

Low-level laser activates Wnt/β-catenin signaling pathway-promoting hair follicle stem cell regeneration and wound healing: Upregulate the expression of key downstream gene Lef 1.

The objective of this study is to investigate the mechanism by which low-level laser stimulation promotes the proliferation of intraepithelial hair follicle stem cells (HFSCs) in wounds. This research aims to expand the applications of laser treatment, enhance wound repair methods, and establish a theoretical and experimental foundation for achieving accelerated wound healing. The experimental approach involved irradiating a cell model with low-level laser to assess the proliferation of HFSCs and examine alterations in the expression of proteins related to the Wnt/β-catenin signaling pathway. A mouse back wound model was established to investigate the effects of low-level laser irradiation on wound healing rate, wound microenvironment, and the proliferation of HFSCs in relation to the Wnt/β-catenin signaling pathway. The research findings indicate that low-level laser light effectively activates the Wnt signaling pathway, leading to the increased accumulation of core protein β-catenin and the upregulation of key downstream gene Lef 1. Consequently, this regulatory mechanism facilitates various downstream biological effects, including the notable promotion of HFSC proliferation and differentiation into skin appendages and epithelial tissues. As a result, the process of wound healing is significantly accelerated. Low levels of laser activates the Wnt signalling pathway, promotes the regeneration of hair follicle stem cells and accelerates wound healing.

Recent safety and efficacy findings from a phase 1b/2 open-label combination study of ASP-1929 photoimmunotherapy with anti-PD-1 therapy in EGFR-expressing advanced head and neck squamous cell carcinoma (HNSCC).

6083 Background: In the challenging landscape of advanced HNSCC, patients (pts) have overall low survival and high locoregional (LR) recurrence rates. While LR progression is a key contributor to morbidity and mortality, LR control remains low despite aggressive therapy including surgery, radiation, chemotherapy, and immunotherapy. ASP-1929 photoimmunotherapy (PIT) combines EGFR-targeting cetuximab, with a light-activatable dye, IRDye 700DX, and a laser light for localized drug activation. This novel approach has demonstrated rapid and selective tumor necrosis in preclinical studies, and a manageable safety profile in HNSCC early clinical trials. Phase I/II and preclinical data indicate a potential synergy in anti-tumor activity of PIT when combined with anti-PD-1 therapy. Here we present updated interim evaluation findings based on a recent data cut from this study initially presented at the 2023 American Head and Neck Society meeting. Methods: A phase 1b/2 open-label study of pts with recurrent locally advanced (rLA) and/or metastatic (m) HNSCC evaluating the safety and efficacy of ASP-1929 PIT in combination with anti-PD-1 (pembrolizumab) therapy (NCT04305795). Pts with measurable disease by modified RECIST 1.1, at least 1 lesion accessible to light illumination, combined positive score (CPS) ≥1, and who were not candidate for LR therapy could be eligible for the study. Treatment included ASP-1929 PIT (infusion day 8, target tumors illuminated 24±4 hours later) plus anti-PD-1 (days 1&22) during a 6-week cycle for up to 24 months. Primary objectives: safety/tolerability; objective response rate (ORR). Secondary objectives: overall survival (OS); progression-free survival (PFS); duration of response (DOR). Planned sample size: 26 HNSCC pts. Results: Of the 19 r/m HNSCC pts enrolled, 18 pts received both study therapies (PIT-evaluable). Data cut-off was August 31, 2023 (previously reported data cut-off: October 4, 2022). Efficacy results updated for the 18 PIT-evaluable pts: ORR of 33.3% (95% CI 13.3-59.0), including 4 CRs (22.2%) and 2 PRs (11.1%). Median OS not reached; 24-month OS rate estimate was 52.4% (95%CI 25.9-73.4). No change in median PFS, 2.9 months (95%CI 1.4-14.6). Median DOR was not reached at data cut-off (range 2.8+ to 18.0+ months). Safety data remained consistent with the data previously presented. Most common serious adverse reactions were dysphagia (10.5%) and tongue edema (10.5%). There were two grade 4 events: laryngeal edema (PIT-related) and tumor hemorrhage due to advanced disease, and no fatal events. Conclusions: ASP-1929 PIT in combination with anti-PD-1 therapy was generally well tolerated. Initial data demonstrate promising overall survival and response rates with this combination therapy in pts with rLA and/or m HNSCC lacking LR treatment options. Clinical trial information: NCT04305795 .

Verteporfin Photodynamic Therapy for the Treatment of Chorioretinal Conditions: A Narrative Review.

Photodynamic therapy (PDT) with verteporfin involves intravenous administration of a photosensitizer followed by its laser light activation at the target site to inhibit aberrant choroidal vascularization. This narrative review provides an overview of the role verteporfin PDT plays in the management of chorioretinal conditions. A PubMed literature review of all English-language articles published through October 19, 2023, was conducted to identify relevant references. Verteporfin PDT has been shown to be safe and effective for the treatment of patients with choroidal neovascularization (CNV) due to neovascular age-related macular degeneration and is often used in combination with a vascular endothelial growth factor (VEGF) inhibitor. Additionally, patients with polypoidal choroidal vasculopathy, a subtype of neovascular age-related macular degeneration, also benefit from verteporfin PDT combined with a VEGF inhibitor for improving visual acuity. Verteporfin PDT has also been effective in treating patients with peripapillary CNV, as well as eyes with CNV due to ocular histoplasmosis and pathologic myopia. Reduced dose and/or fluence PDT protocols have been effective in patients with central serous chorioretinopathy while reducing adverse effects. In eyes with choroidal hemangioma, tumor regression and visual outcomes have been improved with verteporfin PDT treatment. Photodynamic therapy with verteporfin continues to play an important role in the management of chorioretinal conditions.

Analysis of non-linear optical properties of phytochemical photosensitizers in cancer photodynamic therapy by quantum computational

RationalePhotodynamic therapy (PDT) is based on the reactive oxygen species (ROS) generated by light-activated photosensitizers in the presence of oxygen. Phytochemicals are promising natural photosensitizers, offering a potentially less toxic alternative for cancer treatments. Nonlinear optics (NLO) phenomena, such as second-harmonic generation (SHG), third-harmonic generation (THG), and two-photon absorption (TPA), can enhance light interaction, benefiting photosensitizing applications in PDT. Analyzing the NLO properties of phytochemicals can optimize their use in PDT by improving photosensitizer performance and efficacy. AimThis study aims to examine the NLO properties of selected phytochemicals in a reported polyherbal formulation to understand their potential as effective photosensitizers in PDT, thereby advancing cancer treatment options. MethodsQuantum computational calculations were conducted at the B3LYP/6311 G++(d,p) level of theory to unveil crucial information about structural geometry and nonlinear optical properties. ResultsThe bandgap of aloe emodin, emodin, curcumin, scopoletin berberine, furanocoumarin, rubiadin are 3.279 eV, 3.395 eV, 3.247 eV, 3.930 eV, 2.878 eV, 4.463 eV and 3.546 eV, respectively. The results highlight berberine as the most reactive compound, demonstrating high softness and low hardness. Curcumin and furanocoumarin exhibit distinct electron-donating and accepting tendencies, respectively. In the MESP map of furanocoumarin, scopoletin, and rubiadin the electro-negative region is highly oriented around the ketone group (=O) and partially at another O atom in the pentagon. The compensating electropositive charge was distributed elsewhere. In aloe emodin, emodin, and curcumin the electronegativity was distributed around the ketone group while high electropositivity was observed around the substituted hydroxyl functional groups. In berberine electro negative region is very small and it is more electro-positive in nature. All the selected compounds have significantly greater dipole moment than standard urea (1.3732 Debye), specifically scopoletin and curcumin has 8 times greater value than urea. Concerning chemical potential, curcumin emerges as easily reactive, than berberine. The evaluation of NLO properties, including dipole moment (µ), polarizability (α), and mean first hyperpolarizability (β), underscores the superiority of berberine, making it highly reactive and easily activated during laser light irradiation. Discussion and conclusionBerberine exhibits superior NLO properties, marked by high reactivity, substantial softness, and significant first hyperpolarizability, making it the most effective photosensitizer among the studied phytochemicals for enhancing PDT efficacy in cancer treatments.

Estimating differential penetration of green (532 nm) laser light over sea ice with NASA's Airborne Topographic Mapper: observations and models

Abstract. Differential penetration of green laser light into snow and ice has long been considered a possible cause of range and thus elevation bias in laser altimeters. Over snow, ice, and water, green photons can penetrate the surface and experience multiple scattering events in the subsurface volume before being scattered back to the surface and subsequently the instrument's detector, therefore biasing the range of the measurement. Newly formed sea ice adjacent to open-water leads provides an opportunity to identify differential penetration without the need for an absolute reference surface or dual-color lidar data. We use co-located, coincident high-resolution natural-color imagery and airborne lidar data to identify surface and ice types and evaluate elevation differences between those surfaces. The lidar data reveals that apparent elevations of thin ice and finger-rafted thin ice can be several tens of centimeters below the water surface of surrounding leads, but not over dry snow. These lower elevations coincide with broadening of the laser pulse, suggesting that subsurface volume scattering is causing the pulse broadening and elevation shift. To complement our analysis of pulse shapes and help interpret the physical mechanism behind the observed elevation biases, we match the waveform shapes with a model of scattering of light in snow and ice that predicts the shape of lidar waveforms reflecting from snow and ice surfaces based on the shape of the transmitted pulse, the surface roughness, and the optical scattering properties of the medium. We parameterize the scattering in our model based on the scattering length Lscat, the mean distance a photon travels between isotropic scattering events. The largest scattering lengths are found for thin ice that exhibits the largest negative elevation biases, where scattering lengths of several centimeters allow photons to build up considerable range biases over multiple scattering events, indicating that biased elevations exist in lower-level Airborne Topographic Mapper (ATM) data products. Preliminary analysis of ICESat-2 ATL10 data shows that a similar relationship between subsurface elevations (restored negative freeboard) and “pulse width” is present in ICESat-2 data over sea ice, suggesting that biased elevations caused by differential penetration likely also exist in lower-level ICESat-2 data products. The spatial correlation of observed differential penetration in ATM data with surface and ice type suggests that elevation biases could also have a seasonal component, increasing the challenge of applying a simple bias correction.

Assessment of orofacial nociceptive behaviors of mice with the sheltering tube method: Oxaliplatin-induced mechanical and cold allodynia in orofacial regions.

Preclinical studies on pathological pain rely on the von Frey test to examine changes in mechanical thresholds and the acetone spray test to determine alterations in cold sensitivity in rodents. These tests are typically conducted on rodent hindpaws, where animals with pathological pain show reliable nocifensive responses to von Frey filaments and acetone drops applied to the hindpaws. Pathological pain in orofacial regions is also an important clinical problem and has been investigated with rodents. However, performing the von Frey and acetone spray tests in the orofacial region has been challenging, largely due to the high mobility of the head of testing animals. To solve this problem, we implemented a sheltering tube method to assess orofacial nociception in mice. In experiments, mice were sheltered in elevated tubes, where they were quickly accommodated because the tubes provided safe shelters for mice. Examiners could reliably apply mechanical stimuli with von Frey filament, cold stimuli with acetone spray, and light stimuli with a laser beam to the orofacial regions. We validated this method in Nav1.8-ChR2 mice treated with oxaliplatin that induced peripheral neuropathy. Using the von Frey test, orofacial response frequencies and nociceptive response scores were significantly increased in Nav1.8-ChR2 mice treated with oxaliplatin. In the acetone spray test, the duration of orofacial responses was significantly prolonged in oxaliplatin-treated mice. The response frequencies to laser light stimulation were significantly increased in Nav1.8-ChR2 mice treated with oxaliplatin. Our sheltering tube method allows us to reliably perform the von Frey, acetone spray, and optogenetic tests in orofacial regions to investigate orofacial pain.

Intraoral Applications of Lasers in the Prosthetic Rehabilitation with Fixed Partial Dentures-A Narrative Review.

Laser, an acronym for Light Amplification by Stimulated Emission of Radiation, is a powerful tool with diverse applications in modern dentistry. It emits monochromatic, coherent light resulting from photon-induced chain reactions. Available dental lasers include diode, argon, Er,Cr:YSGG, Er:YAG, Nd:YAG, and CO2. The unique property of these lasers, allowing them to be effectively used on both soft and hard tissues based on the operational parameters, positions them as particularly suited for a wide range of dental procedures. Compared to traditional methods, lasers offer advantages such as improved hemostasis and quicker wound healing. Such benefits stress the shift towards laser technology in dental treatment. In the realm of dental prosthodontics, which focuses on esthetics, functionality, and the physiological aspects of dental prostheses, lasers provide promising outcomes. Among the prosthetic options, fixed partial dentures stand out for their ability to mimic natural teeth, offering both esthetic and functional features, leading to satisfactory long-term outcomes if managed properly. This review paper delves into the specific application of laser technology in the context of prosthetic rehabilitation involving fixed partial dentures. By investigating intraoral laser procedures, it contributes to understanding laser's role in improving patients' satisfaction and clinical efficiency in this field.

Molecular templating of layered halide perovskite nanowires.

Layered metal-halide perovskites, or two-dimensional perovskites, can be synthesized in solution, and their optical and electronic properties can be tuned by changing their composition. We report a molecular templating method that restricted crystal growth along all crystallographic directions except for [110] and promoted one-dimensional growth. Our approach is widely applicable to synthesize a range of high-quality layered perovskite nanowires with large aspect ratios and tunable organic-inorganic chemical compositions. These nanowires form exceptionally well-defined and flexible cavities that exhibited a wide range of unusual optical properties beyond those of conventional perovskite nanowires. We observed anisotropic emission polarization, low-loss waveguiding (below 3 decibels per millimeter), and efficient low-threshold light amplification (below 20 microjoules per square centimeter).

Interference characteristics of leaking SF6 on photoacoustic detection of dissolved C2H4 in transformer oil

AbstractSF6 leaked from gas insulation equipment will interfere with the detection of dissolved characteristic gases in transformer oil. In order to determine the impact of SF6 on the detection of dissolved C2H4 gas in oil, a photoacoustic (PA) C2H4 detection system based on the combination of mid‐infrared thermal radiation source and near‐infrared laser was constructed. The excitation light from two bands was incident on a non‐resonant PA cell. The thermal radiation light source and the laser light source were switched to evaluate the interference level of SF6 on the detection of C2H4. The experimental results show that SF6 has significant interference to C2H4 when using a mid‐infrared thermal radiation light source. The interference coefficient is 2014%. The near‐infrared laser based on PA detection method can effectively suppress the interference of SF6 on C2H4. The minimum detection limit of C2H4 reaches 0.6 ppm when the average time is 60 s.

Photobiomodulation mitigates Bothrops jararacussu venom-induced damage in myoblast cells by enhancing myogenic factors and reducing cytokine production.

Photobiomodulation has exhibited promise in mitigating the local effects induced by Bothrops snakebite envenoming; however, the mechanisms underlying this protection are not yet fully understood. Herein, the effectiveness of photobiomodulation effects on regenerative response of C2C12 myoblast cells following exposure to Bothrops jararacussu venom (BjsuV), as well as the mechanisms involved was investigated. C2C12 myoblast cells were exposed to BjsuV (12.5 μg/mL) and irradiated once for 10 seconds with laser light of 660 nm (14.08 mW; 0.04 cm2; 352 mW/cm2) or 780 nm (17.6 mW; 0.04 cm2; 440 mW/ cm2) to provide energy densities of 3.52 and 4.4 J/cm2, and total energies of 0.1408 and 0.176 J, respectively. Cell migration was assessed through a wound-healing assay. The expression of MAPK p38-α, NF-Кβ, Myf5, Pax-7, MyoD, and myogenin proteins were assessed by western blotting analysis. In addition, interleukin IL1-β, IL-6, TNF-alfa and IL-10 levels were measured in the supernatant by ELISA. The PBM applied to C2C12 cells exposed to BjsuV promoted cell migration, increase the expression of myogenic factors (Pax7, MyF5, MyoD and myogenin), reduced the levels of proinflammatory cytokines, IL1-β, IL-6, TNF-alfa, and increased the levels of anti-inflammatory cytokine IL-10. In addition, PBM downregulates the expression of NF-kB, and had no effect on p38 MAKP. These data demonstrated that protection of the muscle cell by PBM seems to be related to the increase of myogenic factors as well as the modulation of inflammatory mediators. PBM therapy may offer a new therapeutic strategy to address the local effects of snakebite envenoming by promoting muscle regeneration and reducing the inflammatory process.

Studying the viability and growth kinetics of vancomycin-resistant Enterococcus faecalis V583 following femtosecond laser irradiation (420–465 nm)

Enterococcus faecalis is among the most resistant bacteria found in infected root canals. The demand for cutting-edge disinfection methods has rekindled research on photoinactivation with visible light. This study investigated the bactericidal activity of femtosecond laser irradiation against vancomycin-resistant Enterococcus faecalis V583 (VRE). The effect of parameters such as wavelength and energy density on the viability and growth kinetics of VRE was studied to design an optimized laser-based antimicrobial photoinactivation approach without any prior addition of exogenous photosensitizers. The most effective wavelengths were 430 nm and 435 nm at a fluence of 1000 J/cm2, causing a nearly 2-log reduction (98.6% and 98.3% inhibition, respectively) in viable bacterial counts. The colony-forming units and growth rate of the laser-treated cultures were progressively decreased as energy density or light dose increased at 445 nm but reached a limit at 1250 J/cm2. At a higher fluence of 2000 J/cm2, the efficacy was reduced due to a photobleaching phenomenon. Our results highlight the importance of optimizing laser exposure parameters, such as wavelength and fluence, in bacterial photoinactivation experiments. To our knowledge, this is the first study to report an optimized wavelength for the inactivation of VRE using visible femtosecond laser light.

Design of 1450-1500nm Bismuth-doped Fiber Laser

With the rapid development of information technology, people's demand for the transmission capacity of fiber optic communication networks is increasing. How to broaden the bandwidth of communication systems has become one of the key issues in the field of communication. Researchers have found that the operating bandwidth of amplifiers mainly limits the bandwidth of communication systems. Although multiple solutions have been proposed and implemented to address this issue, there are still many gaps in the design of full-band multi wavelength-related light sources. By studying the three-level system of bismuth ions, the rate equation and power transfer equation of a bismuth ion doped fiber laser are simulated, and the pump power threshold and output power are calculated. Using MATLAB for simulation experiments, the relationship between laser power and pump power, as well as their variation with propagation distance, were ultimately obtained. The simulation results show that under 830 pump lights, the pump light threshold power is 10W. After reaching the threshold power, the pump light power and laser power have a linear relationship, and as the propagation distance increases, the pump light power gradually decreases and the laser power gradually increases. The analysis shows that the power generated by the signal light in this band meets the theoretical standards, which verifies the correctness of the scheme.

Exploring the structural, functional, and biocompatibility aspects of marine bacterial extracellular polysaccharides for biopharmaceutical applications

Marine bacterial extracellular polysaccharides (EPS) represent a unique class of biopolymers with vast potential in biopharmaceutical research due to their diverse structural characteristics, functional properties, and biocompatibility. This study delves into the comprehensive analysis of the monosaccharide composition, molecular weight distribution, and conformational dynamics of marine bacterial EPS, employing advanced analytical techniques such as Nuclear Magnetic Resonance (NMR) spectroscopy, Mass Spectrometry (MS), and Size-Exclusion Chromatography coupled with Multi-Angle Laser Light Scattering (SEC-MALLS). Furthermore, we explore the functional applications of these EPS in biofilm inhibition, immunomodulation, and as innovative drug delivery systems, highlighting their role in enhancing antibiotic efficacy and mitigating resistance. Through quantitative analysis and mathematical modeling, including rheological studies and kinetic modeling of biodegradation, this work assesses the EPSs biocompatibility and biodegradability, essential for their safe use in biomedicine. Our findings underscore the potential of marine bacterial EPS in developing novel biopharmaceutical formulations that are not only effective but also environmentally sustainable and biocompatible, paving the way for future advancements in medical and therapeutic applications.

Boosting the in-vitro effectiveness of photodynamic therapy on MCF-7 breast cancer cells with encapsulated malachite green by silica nanoparticles

Photodynamic therapy (PDT) is a promising cancer treatment strategy utilizing photosensitizers (PS) and light to generate singlet oxygen, with Malachite Green (MG) showing high singlet oxygen quantum yield. Effective delivery of MG to the target tissue remains a key challenge. Encapsulation techniques have been investigated to improve PS delivery, minimize PS leakage, inhibit diaphorase-induced reduction, and mitigate PS-related toxicity. Silica nanoparticles (SiNPs) offer favorable characteristics for drug delivery in PDT and serve as promising delivery carriers. In this study, SiNPs were synthesized and employed as carriers for MG. The size and shape of nanoparticles were determined using Transmission Electron Microscopy (TEM). A range of concentrations of MG were applied to MCF-7 breast cancer cells in order to evaluate the cytotoxicity of both naked and encapsulated MG. This helped identify the most effective concentrations and exposure durations required to induce damage under red laser light (Intensity ∼110 mW/cm2). The results indicated that SiNPs-encapsulated MG exhibited superior efficacy compared to naked MG, with a concentration efficacy increase of +50 % and an exposure time efficacy increase of +45 %. This underlines the enhanced capability of encapsulated MG to eliminate MCF-7 cells when compared to naked MG. The application of synthesized SiNPs for MG delivery improved the effectiveness of photodynamic therapy by augmenting MG bioavailability in target cells.

Photodynamic therapy mediated by methylene blue-loaded PEG accelerates skin mouse wound healing: an immune response

PurposeConventional approaches for enhancing wound healing may not always yield satisfactory results. Instead, we test the effectiveness of a newly developed photodynamic therapy (PDT) that uses methylene blue (MB) loaded with polyethylene glycol (PEG) (MB-PEG) hydrogel to accelerate wound healing process in mice.MethodsA dorsal skin incision with 6 mm punch which topically subjected to MB-PEG hydrogel and a low-level laser light of red light to assess the regeneration process of wounded skin. A total of 63 adult male CD1 mice divided into normal group (no treatment) and other wound groups received different treatments of laser (650 ± 5 nm and power intensity of 180 mW/cm2), MB-PEG, or PDT (MB-PEG followed by laser). The wound healing parameters were investigated by histological examination of the skin and measuring of proinflammatory cytokines at the early stage (48 h) and a late one on day 21. Results: at 48 h, the score of tissue granulation, inflammation, and angiogenesis process were markedly improved in wounded groups that received MB + PEG combined with laser compared to the group treated with laser alone. On day 21, a significant improvement of the inflammation was detected in the group treated with MB + PEG plus laser compared to the other groups. At 48 h, the upregulated serum levels of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in the wound group were significantly (P < 0.001) reduced in the group treated with MB + PEG combined with laser.ConclusionMB-PEG based hydrogel improves and accelerates wound closure in the context of laser compared to either single treatment.

Facile way of preparing PMMA@TiO2@SiO2 (P@T@S) composite microspheres with high haze and light transmittance for diffusion film

AbstractIn recent years, optical diffusion film materials with high transmittance and high haze have been widely reported, while there is relatively rare research on their functionalization and practical application especially in real scenario. In this work, optical diffusion films using polymethyl methacrylate (PMMA)@TiO2@SiO2 (P@T@S) composite microspheres were fabricated, which exhibited sufficiently high light transmittance and haze. The binding mode of PMMA microspheres and nanoparticles suggested that PMMA microspheres with a positive surface potential combined with nanoparticles with a negative surface potential through electrostatic attraction to achieve mutual binding. The prepared P@T@S composite microspheres showed better heat and swelling resistance than those of PMMA microspheres. The P@T@S diffusion film, whose excellent light diffusion effect was clearly demonstrated, exhibited the best optical performance among all optical diffusion films prepared. After passing through the P@T@S diffusion film, the laser light was not only uniform but also bright. The findings from this work can provide some insight into further research on optical diffusion films applied in optoelectronic device areas.

Design and Development of a Non-invasive Opto-Electronic Sensor for Blood Glucose Monitoring Using a Visible Light Source.

Background The management of diabetes is critically dependent on the continuous monitoring of blood glucose levels. Contemporary approaches primarily utilize invasive methods, which often prove to be uncomfortable and can deter patient adherence. There is a pressing need for the development of novel strategies that improve patient compliance and simplify the process of glucose monitoring. Aim and objectives The primary objective of this research is to develop a non-invasive blood glucose monitoring system (NIBGMS) that offers a convenient alternative to conventional invasive methods. This study aims to demonstrate the feasibility and accuracy of using visible laser light at a wavelength of 650 nm for glucose monitoring and to address physiological and technical challenges associated with in vivo measurements. Methods Our approach involved the design of a device that exploits the quantitative relationship between glucose concentration and the refraction phenomena of laser light. The system was initially calibrated and tested using glucose solutions across a range of concentrations (25-500 mg/dL). To get around the problems that come up when people's skin and bodies are different, we combined an infrared (IR) transmitter (800 nm) and receiver that checks for changes in voltage, which are indicative of glucose levels. Results The prototype device was compared with a commercially available blood glucose monitor (Accu-Chek active machine; Roche Diabetes Care, Inc., Mumbai, India). The results demonstrated an average linearity of 95.7% relative to the Accu-Chek machine, indicating a high level of accuracy in the non-invasive measurement of glucose levels. Conclusions The findings suggest that our NIBGMS holds significant promise for clinical application. It reduces the discomfort associated with blood sampling and provides reliable measurements that are comparable to those of existing invasive methods. The successful development of this device paves the way for further commercial translation and could significantly improve the quality of life for individuals with diabetes, by facilitating easier and more frequent monitoring.