Transparent Gel Research Articles

Focus control of a concave–convex ultrasonic gel lens in the radial direction

Optical image stabilization (OIS) systems maintain the three-dimensional focal position of a lens through mechanical actuation systems. This paper examines an optical lens for OIS that utilizes ultrasound vibration to alter the focal position, not only in the depth direction but also in the radial direction. The lens has a simple structure with no mechanical moving parts and consists of an ultrasound transducer divided into four pieces, a glass disk, and a transparent viscoelastic gel film that functions as a lens. The acoustic radiation force generated by the resonant flexural vibration of the glass disk can alter the surface profile of the gel film, allowing for a variable-focus function. The concave and convex lenses can be interchanged using two resonant vibration modes: the standing-wave mode, in which the vibration loop appears at the center, and the traveling-wave mode, in which the vibration node appears at the center. The positions of ultrasound vibrations on the lens can be controlled in a two-dimensional plane by adjusting the driving amplitudes of each channel, thereby achieving focus control in the radial direction. The focusing characteristics of the lens are evaluated through ray-tracing simulation.

Characterization and Evaluation of the Cytotoxicity of Pregabalin Gels for Oral Application.

The efficacy of pregabalin in pain treatment has led to the search for new formulations for its use through different routes of administration. This study aimed to prepare, characterize, and evaluate the cytotoxicity of pregabalin (PG) gels for topical application in the oral cavity. Solutions with three different concentrations of PG were prepared and added to a 1.0% carbopol gel base. Thermal analyses (TG and DSC) and FTIR were performed on the gel and pure pregabalin. Stability (preliminary and accelerated) and rheology studies were also conducted on the gels. Cytotoxicity was evaluated in human gingival fibroblasts in the following groups: WG (1.0% carbopol gel base), PG2G (2.0% pregabalin gel), PG5G (5.0% pregabalin gel), and PG10G (10% pregabalin gel). A transparent and homogeneous gel with a pH of 6 was obtained. The formulations showed stability, and the different drug concentrations did not influence the product's characteristics. None of the tested groups showed cytotoxicity for the analyzed cells. The pregabalin gels exhibited favorable and non-toxic characteristics for human gingival fibroblasts in vitro. Therefore, this product may be a promising therapeutic alternative for topical application in the oral mucosa.

Improvement of pasting behavior and retrogradation inhibition of normal corn starch treated with phytic acid and malic acid

Phytic acid (PA) and malic acid (MA), as environmentally friendly, plant-based water-soluble acids, were applied to normal corn starch during dry heating at mildly acidic pH to improve its gelatinization and retrogradation behaviors. A significant increase in peak viscosity (5011–6338 mPa·s) was observed in starch treated with MA compared to native corn starch (1162 mPa·s). The treatment with PA and MA further increased the peak viscosity (8140–8621 mPa·s). The interactions of PA and MA with starch were analyzed using ICP-OES, FTIR, and 13C CP/MAS NMR. Swelling power and solubility increased in MA and PA + MA starches. After storage at 4 °C for 14 d, MA and PA + MA starches produced transparent and fluid gels without forming B-type crystals, which indicated inhibition of starch retrogradation by PA and MA treatments. In conclusion, dry heating with PA and MA produced starch with remarkably superior paste viscosity, swelling, and inhibition of retrogradation.

Dynamic multicolor electrochromic skin in high-brightness flexible WO3/Au asymmetric Fabry–Perot nanocavity fabricated on Nylon 66 porous substrate

Recently, the Fabry–Perot (F–P) cavity electrochromic devices, which are constructed by combining nano-size inorganic electrochromic material WO3 and reflective metal layers, have attracted considerable attention due to their potentials in the fields of dynamic multicolor displays and active camouflage. However, in the few studies that have been reported, the peak reflectance of flexible F–P cavity multicolor electrochromic devices in the visible wavelength band is generally lower than 30 %, which limits their reflective display and camouflage effects in high-brightness environments. Thus, we have combined multicolor reflective electrochromic electrodes in WO3/Au asymmetric F–P nanocavity constructed by magnetron sputtering on a Nylon 66 porous substrate with a highly transparent UV-cured gel electrolyte and a PET plastic sealing procedure. As a result, a flexible and dynamic multicolor electrochromic skin with high reflectance (Rmax＞50 %) and excellent flexibility (bending radius of 4 mm) has been fabricated. The WO3 electrochromic layer at the top works as the dynamic dielectric layer in the broadband absorption Fabry–Perot cavity, and the inert metal Au layer at the bottom works as the reflective layer. The WO3/Au asymmetric F–P cavity can acutely capture the variation in optical constants of WO3 due to the thickness change and electric-driven effects. This cavity facilitates the selective reflection and absorption of the energy distribution of the spectrum after the induced interferometric resonance. As a result, the cavity exhibits a rich array of structural colors, including ocher, taupe, yellow, orange, green, and violet. The electrochromic skin exhibits a fast switching time and maintains 99.43 % of the optical modulation amplitude (ΔR) after 110 coloring/bleaching cycles. It provides a potential option in the field of flexible high-brightness reflective displays and dynamic camouflage in the future.

Ultrasonic aperture-tunable gel lens

Conventional camera modules require mechanical moving parts to move their lenses and to adjust their focal points. This paper examines optically tunable lenses with a focal length and lens aperture that can be controlled using ultrasound vibration and a transparent gel. The lens uses the acoustic radiation force, which induces changes in the lens profile; varifocal convex and concave lenses can be fabricated by adjusting the input signals. The optical characteristics of the lenses were evaluated using ray tracing simulations. The aperture can be controlled with the driving frequency, with higher frequencies leading to a wider range of focal length changes with a lower input voltage.

DEVELOPMENT OF ZINC-LOADED HYDROGEL INFUSED WITH ALOE BARBADENSIS MUCILAGE FOR WOUND HEALING

This study aims to formulate and characterize zinc-loaded hydrogel infused with Aloe barbadensis mucilage for wound dressing. Five formulations containing varying proportions of carbopol, zinc, aloe and water (as vehicle) were developed via physical crosslinking using triethanolamine. All formulations had a translucent off-white colour while the control gave a transparent gel. The viscosity was highest in the control, 30000.00 ± 2.07 PaS. The pH of the formulations was between 5.7 and 5.8. Formulation 2 which is composed of 30 mg of Zinc and 1.4 mg of Aloe barbadensis incorporated into 1% w/v Carbopol Ultrez hydrogel polymer had the lowest swelling index of 79.2 ± 1.95% implying that it had the fastest drug release rate. The wounds treated with Formulation 2 had the most rapid wound healing with no sign of scars in the wound area. Histomorphometric evaluation reflected a high re-epithelisation rate of 70%, a significant percentage occupied by collagen in granulation tissue of 85%. The thickness of the tissue's central region was 10 mm. The inflammatory cells /mm2 tissue was 200 cells/mm2 while the number of microvessels in granulation tissue was 1.0 microvessels/mm2. Zinc-loaded hydrogel infused with Aloe barbadensis mucilage shows great potential as a modern wound dressing.

Formulation and Evaluation of Soap Containing Extracts of Various Ethnomedicines

The herbal soap’s formulation includes neem leaf; all herbal ingredients are easily obtained from the local herbal market. Use of cosmetics is part of caring for the skin and other body parts due to the damaging effects of modern pollution and UV rays on human health; aloe plants produce a material used in cosmetic goods to treat burns, psoriasis, acne, and other skin disorders; preparation of herbal soap is a medication or therapy with therapeutic benefits for the skin, including antibacterial and antifungal qualities; the raw material used to make soap has a number of properties that make it a good medicinal or cosmetic. The plant used to manufacture soap has properties that can help eliminate acne, soften the skin’s epidermis, increase penetration, and hasten healing and resolution. Natural remedies like aloe vera are used to both prevent and cure a range of skin conditions. The medicinal properties of aloe vera soap include antiseptic, antimicrobial, antiviral, antioxidant, and antifungal properties. The aloe vera plant features tubular yellow blossoms, many-seeded fruits, and triangular, fleshy leaves with serrated edges. Each leaf consists of three layers: an inner, transparent gel that contains 99% water and glucomannans, amino acids, lipids, sterols, and vitamins in the remaining 2%. The intermediate layer of latex is composed of a bitter-yellow sap. Neem provides additional medicinal benefits. Studies have demonstrated the anti-inflammatory, anti-hyperglycemic, anti-ulcer, antimalarial, antifungal, antibacterial, antimutagenic, and anticarcinogenic properties of neem and its chemical components. Tulsi provides many skin-benefiting qualities, such as beep-clean skin. Turmeric and vitamin C are also used to help tone the skin when treating breakouts. Homegrown cleaning solutions with medicinal or sedative qualities, such as antimicrobial and antifungal qualities, can benefit the skin. The rough material used in the cleanser formulation has multiple prescription drugs or cosmetics attached to it. The plant used in cleanser formulations has the ability to smooth out skin imperfections, enhance skin texture, prevent breakouts, and hasten healing and resolution.

Construction of a novel tissue engineered meniscus scaffold based on low temperature deposition three-dimenisonal printing technology

To investigate the construction of a novel tissue engineered meniscus scaffold based on low temperature deposition three-dimenisonal (3D) printing technology and evaluate its biocompatibility. The fresh pig meniscus was decellularized by improved physicochemical method to obtain decellularized meniscus matrix homogenate. Gross observation, HE staining, and DAPI staining were used to observe the decellularization effect. Toluidine blue staining, safranin O staining, and sirius red staining were used to evaluate the retention of mucopolysaccharide and collagen. Then, the decellularized meniscus matrix bioink was prepared, and the new tissue engineered meniscus scaffold was prepared by low temperature deposition 3D printing technology. Scanning electron microscopy was used to observe the microstructure. After co-culture with adipose-derived stem cells, the cell compatibility of the scaffolds was observed by cell counting kit 8 (CCK-8), and the cell activity and morphology were observed by dead/live cell staining and cytoskeleton staining. The inflammatory cell infiltration and degradation of the scaffolds were evaluated by subcutaneous experiment in rats. The decellularized meniscus matrix homogenate appeared as a transparent gel. DAPI and histological staining showed that the immunogenic nucleic acids were effectively removed and the active components of mucopolysaccharide and collagen were remained. The new tissue engineered meniscus scaffolds was constructed by low temperature deposition 3D printing technology and it had macroporous-microporous microstructures under scanning electron microscopy. CCK-8 test showed that the scaffolds had good cell compatibility. Dead/live cell staining showed that the scaffold could effectively maintain cell viability (>90%). Cytoskeleton staining showed that the scaffolds were benefit for cell adhesion and spreading. After 1 week of subcutaneous implantation of the scaffolds in rats, there was a mild inflammatory response, but no significant inflammatory response was observed after 3 weeks, and the scaffolds gradually degraded. The novel tissue engineered meniscus scaffold constructed by low temperature deposition 3D printing technology has a graded macroporous-microporous microstructure and good cytocompatibility, which is conducive to cell adhesion and growth, laying the foundation for the in vivo research of tissue engineered meniscus scaffolds in the next step.

Experimental investigation of the flow-induced vibration of a hybrid riser conveying severe slugging

This paper reports the experimental results of the vibration response of a hybrid riser conveying severe slugging. The hybrid riser comprises a vertical rigid riser made of a transparent acrylic tube and a flexible jumper made of a transparent silica gel tube with a length to internal diameter ratio of 261. The horizontal span and vertical height of the flexible jumper are 83.5 and 45 cm, respectively. The flow-induced vibration tests were carried out in the liquid superficial velocity range of Vsl = 0.098–0.688 m/s and the gas superficial velocity range of Vsg = 0.177–0.649 m/s using non-intrusive optical measurement with high-speed cameras. Five flow regimes are observed, including the severe slugging I (SSI), severe slugging II (SSII), severe slugging III (SSIII), stable flow (ST), and oscillation flow regimes. The vibration response of the flexible jumper is related to the flow regime. As the flow regime changes from SSI to SSII, the absence of the slug production stage results in an augmented amplitude. In contrast, the response amplitude is significantly reduced when the flow regime shifts to ST. For the SSI regime, the response amplitude varies over the stage, and the occurrence of multiple frequencies is associated with the pressure fluctuation as well as the different duration of stages. The maximum amplitude is observed in the liquid fallback stage in spite of the limited duration, and the vibration frequency is close to the fundamental natural one. The liquid slugs of different lengths passing through the jumper at different velocities contribute to the presence of the traveling wave characteristic.

Experimental Study of the Implantation Process for Array Electrodes into Highly Transparent Agarose Gel.

Brain-computer interface (BCI) technology is currently a cutting-edge exploratory problem in the field of human-computer interaction. However, in experiments involving the implantation of electrodes into brain tissue, particularly high-speed or array implants, existing technologies find it challenging to observe the damage in real time. Considering the difficulties in obtaining biological brain tissue and the challenges associated with real-time observation of damage during the implantation process, we have prepared a transparent agarose gel that closely mimics the mechanical properties of biological brain tissue for use in electrode implantation experiments. Subsequently, we developed an experimental setup for synchronized observation of the electrode implantation process, utilizing the Digital Gradient Sensing (DGS) method. In the single electrode implantation experiments, with the increase in implantation speed, the implantation load increases progressively, and the tissue damage region around the electrode tip gradually diminishes. In the array electrode implantation experiments, compared to a single electrode, the degree of tissue indentation is more severe due to the coupling effect between adjacent electrodes. As the array spacing increases, the coupling effect gradually diminishes. The experimental results indicate that appropriately increasing the velocity and array spacing of the electrodes can enhance the likelihood of successful implantation. The research findings of this article provide valuable guidance for the damage assessment and selection of implantation parameters during the process of electrode implantation into real brain tissue.

Formation of gel and solid phases in acrylic cuvettes upon exposure to DMSO, oxygen and light: implications for fluorescence spectroscopy

We here report the formation of a turbid-gel phase in acrylic cuvettes upon exposure to pure Dimethyl Sulfoxide (DMSO) at room temperature. The observed phenomenon occurred over a 10 h to 14 h incubation in the presence of environmental oxygen. After the turbid gel was removed from the cuvette, it became a white solid exhibiting unique emission behavior. The formation of the turbid-gel phase was accelerated upon exposure to UV 295 LED pulses of light from 6 h to 8 h. Surprisingly, subsequent exposure of the white solid to a few microliters of pure DMSO and vortexing resulted in its transformation into a transparent gel state in just a few minutes, eventually acquiring transparent and liquid properties. Additionally, the white-solid phase can load other molecules, such as Resveratrol and Quercetin, leading to shifts in the respective emission spectra compared with the same molecule in liquid and pure DMSO. These novel findings highlight the interaction between UV photons, oxygen, DMSO and Acrylic, and potentially distort fluorescence spectroscopy experiments.

Gellan Gum as a Unique Microbial Polysaccharide: Its Characteristics, Synthesis, and Current Application Trends.

Gellan gum (GG) is a linear, negatively charged exopolysaccharide that is biodegradable and non-toxic. When metallic ions are present, a hard and transparent gel is produced, which remains stable at a low pH. It exhibits high water solubility, can be easily bio-fabricated, demonstrates excellent film/hydrogel formation, is biodegradable, and shows biocompatibility. These characteristics render GG a suitable option for use in food, biomedical, and cosmetic fields. Thus, this review paper offers a concise summary of microbial polysaccharides. Moreover, an in-depth investigation of trends in different facets of GG, such as biosynthesis, chemical composition, and physical and chemical properties, is emphasized. In addition, this paper highlights the process of extracting and purifying GG. Furthermore, an in-depth discussion of the advantages and disadvantages of GG concerning other polysaccharides is presented. Moreover, the utilization of GG across different industries, such as food, medicine, pharmaceuticals, cosmetics, etc., is thoroughly examined and will greatly benefit individuals involved in this field who are seeking fresh opportunities for innovative projects in the future.

Gelatin-Immobilized Cu(II) Metal Complex: Synthesis and Applications

Gelatin, resulting from collagen, a naturally occurring protein found in ligaments and tissues, is formed through the boiling of connective tissues, bones and animal skins, commonly sourced from cows. Its exceptional properties, including the ability to form strong, transparent gels and flexible films, easy digestibility, solubility in hot water and positive binding action, make gelatin a highly valuable resource in various industries such as food processing, pharmaceuticals, photography and paper production. It is regarded as non-toxic, biocompatible, biodegradable and generally safe for use. Gelatin serves as a key ingredient in the manufacturing of a wide range of products, with a notable example being hard gelatin capsules, which come in varying levels of solubility in water. In this study, a Schiff base was synthesized by modifying gelatin with salicylaldehyde in ethanol at room temperature, a mixture of gelatin-Schiff base added to appropriate copper chloride sonicated in ethanol, the mixture was poured onto glass plates and allowed to dry. Modified gelatin film was produced and characterized using FTIR spectroscopy, while its surface properties were examined through Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Furthermore, the modified gelatin film’s potential biological activity was assessed against bacterial strains. The antibacterial screening tests revealed that the modified gelatin exhibited promising antibacterial activity against microorganisms, indicating an improvement in its antibacterial efficacy. These findings highlight the enhanced antibacterial potential of the modified gelatin film, further contributing to its versatility and potential applications in various fields. Different molecular weight distributions within the gelatin can lead to variations in film formation and subsequent surface features. Additionally, the composition of the gelatin film, including the presence of any crosslinking agents or modified functional groups, can further influence the resulting surface morphology. This study focuses on the preparation of modified gelatin films using suitable aldehyde compounds and explores their potential for pharmaceutical applications. Various techniques assessment of biological activity will be employed to investigate the properties and performance of the modified gelatin films. HIGHLIGHTS A Schiff base was synthesized by modifying gelatin with salicylaldehyde, a mixture of gelatin-Schiff base added to appropriate copper chloride to produce gelatin-Schiff base-Cu(II) complex Modified gelatin characterized using FTIR spectroscopy, while its surface properties were examined through SEM and AFM The modified gelatin film’s potential biological activity was assessed against bacterial strains GRAPHICAL ABSTRACT

A wearable electrostimulation-augmented ionic-gel photothermal patch doped with MXene for skin tumor treatment

A wearable biological patch capable of producing multiple responses to light and electricity without interfering with daily activities is highly desired for skin cancer treatment, but remains a key challenge. Herein, the skin-mountable electrostimulation-augmented photothermal patch (eT-patch) comprising transparent ionic gel with MXene (Ti3C2Tx) doping is developed and applied for the treatment of melanoma under photostimulation at 0.5 W/cm2. The eT-patch designed has superior photothermal and electrical characteristics owing to ionic gels doped with MXene which provides high photothermal conversion efficiency and electrical conductivity as a medium. Simultaneously, the ionic gel-based eT-patch having excellent optical transparency actualizes real-time observation of skin response and melanoma treatment process under photothermal and electrical stimulation (PES) co-therapy. Systematical cellular study on anti-tumor mechanism of the eT-patch under PES treatment revealed that eT-patch under PES treatment can synergically trigger cancer cell apoptosis and pyroptosis, which together lead to the death of melanoma cells. Due to the obvious advantages of relatively safe and less side effects in healthy organs, the developed eT-patch provides a promising cost-effective therapeutic strategy for skin tumors and will open a new avenue for biomedical applications of ionic gels.

Deionization-induced colorless transparency in physical gels formed by clay aqueous dispersions

Physical gels formed by aqueous clay dispersion are typically turbid and have a milky appearance. The colorless and transparent nature of gels expands the potential for novel applications. In this study, we successfully produced a transparent gel by deionizing the gel as much as possible while maintaining its dynamic elastic modulus, akin to water. The aqueous clay suspensions exhibited specific sol-gel regions corresponding to the type of clay. According to images obtained through cryo-SEM, the three-dimensional network formed by clay became finer when deionization was carried out, and the aqueous dispersion exhibited Rayleigh scattering. The reduction in the extent of Mie scattering due to the suppression of clay aggregation through deionization results in its colorless transparency. This transparent gel will open up various potential applications, including 3D printing support structures, 3D cell culture, 3D art and displays with dispersed materials, educational materials with visual effects, enhancing traditional products, and innovative engineering applications.

Transparent succinonitrile-modified polyacrylate gel polymer electrolyte for solid electrochromic devices

Transparent gel electrolytes have the advantage of optical transparency, higher ionic conductivity, and better electrode adhesion compared with solid inorganic electrolytes, which is of great significance in solid-state electrochromic glass and other electrochemical applications. Here, succinonitrile-modified polyacrylate gel polymer electrolyte (SN-GPE) has been successfully synthesized via an in-situ thermal polymerization under mild conditions. Adopted succinonitrile significantly improves ionic conductivity from 0.02 mS·cm−1 to 4.02 mS·cm−1, maintaining advantageous features such as high transparency and excellent electrochemical performance. The optimized SN-GPEs with good adhesion to both counter and working electrodes were assembled in semi-devices with a configuration of glass/FTO/WO3/SN-GPE/FTO/glass, which showed an excellent optical modulation (ΔT) of 34.5 % at λ = 633 nm and fast response time 4 s/20 s for bleaching/coloration by applying a bias voltage ± 2.8 V, and promising cycling stability with ΔT maintaining 90 % of the original after 2840 cycles, indicative of an extensive potential in the applications of the solid or flexible electrochromic devices. This work significantly broadens the transparent electrolyte family for advanced large-scale electrochromic devices.

Design and characterization of nano sponges loaded vaginal gels of Voriconazole

Objectives: The current inquiry of this research job is to build and analyze a bio adhesive vaginal gel that is packed with Voriconazole Nano sponge for an extended residence duration at the point of infection, resulting in a positive drug release profile. Methods: Nano sponges were created using a solvent evaporation process in varied Voriconazole to β-cyclodextrin ratios. Zeta possibility, polydispersity, size of particles analysis, capture efficiency, and surface morphology of Nao sponges are all determined using scanning microscopes with electrons (SEM). FTIR and DSC investigations were used to determine drug excipient compatibility. Carbopol/Hypromellose/Sodium Carboxymethyl cellulose/HPC has been used to make the bio adhesive gel, while both propyl paraben and a methyl para were employed as antioxidants. Triethanolamine, also was used to regulate the pH, resulting in a transparent gel. The gel base has been incorporated with the improved Voriconazole Nano sponge mixture. The pH, viscosity, spread ability, extrudability, and medication content of Nano sponge in mixes of gels were all investigated. The gel's in vivo diffusion has been examined on goat vaginal mucosal. Cellophane membranes was used in an artificial drug release examination. Results: The improved generation of IDLNS12 Nano sponge (drug-polymer ratio 1:1) demonstrated 91.56% entrapment efficiency. The average particle diameter of all formulations was less than 310 nm. The SEM photographs revealed smooth and spherical particles. INSG4 (Carpool and HPC) gel formulation had a viscosity value of 4529 cps at 2-10 RPM, a gel strength of 92.65N load, and an expansion speed of 37.24 g.cm/seconds. At 12.0 minutes, INSG4 achieved 99.98% drug release. And a mucous adhesive time of in excess of 12 hours. Conclusion: These results suggest that Voriconazole-loaded β-cyclodextrin Nano sponge in mucous adhesive gel might be used for managing infections of vagina perpetually.

Designing Self-Sustained Hydrogel Electrolytes for Aqueous, Transparent, and Flexible Batteries

The arrival of aqueous sodium-ion batteries has been an essential sustainable advancement in energy storage devices. The use of electrolytes based on polymeric hydrogel is emerging due to the facility in which they can be obtained as film, flexibility, and high ionic conductivity. Additionally, these electrolytes have a dual purpose by acting also as separators. This work deals with the preparation and characterization of hydrogels based on polyvinyl alcohol (PVA), sodium chloride (NaCl), and boric acid (H3BO3) to be used as electrolytes in transparent and flexible aqueous sodium-ion batteries. It was observed that lower amounts of NaCl yielded transparent and conductive gels, while increasing the amount of NaCl yielded translucent samples, due to the non-dissolved NaCl. The preparation, gelation step and electrode deposition were optimized to achieve the maximum transparency and conductivity. Subsequently, the selected electrolyte was applied in symmetric devices based on transparent nanocomposite films as electrodes. These devices demonstrated both high transparency and grand current rates. Furthermore, the performance of the electrolyte was verified in a flexible and symmetrical device, revealing an increased current, indicating improved electrode/electrolyte contact. This observation underscores the efficacy of hydrogels in enhancing device performance, particularly in flexible configurations.

Non-thermal CO2 Laser Therapy (NTCLT): A Novel Photobiomodulative Approach for Immediate Pain Relief of Patchy Oral Mucositis Due to Chemotherapy of Solid Tumors.

Introduction: Chemotherapy-induced oral mucositis (COM) is a prominent complication of chemotherapy (CT). Non-thermal CO2 laser therapy (NTCLT) has been demonstrated as an innovative and safe photobiomodulative approach in some kinds of painful oral lesions. The purpose of this study was to evaluate the palliative effects of one session of NTCLT on COM lesions. Methods: Patients with painful COM (WHO grade:≥2) were included in this before-after clinical trial based on the eligibility criteria. The oral lesions were irradiated with a CO2 laser (power: 1 W, scanning the lesions with the rapid circular motion of the defocused handpiece) through a thick layer (3-4 mm) of a transparent gel containing a high-water content. The severity of pain in the lesions was self-assessed using a 0-to-10 visual analogue scale (VAS) for 7 consecutive days. The evaluating physician visited the patients on the 3rd and 7th days in search of any kind of complications. Results: Seventeen adult patients with 35 patches of OM due to chemotherapy of solid tumors completed the trial. Immediately after NTCLT, the mean for non-contact VAS pain scores of the lesions significantly declined from 4.91±2.356 to 0.29±0.622 (P<0.001) and the mean for contact VAS pain scores from 7.77±1.57 to 1.31±1.18 (P<0.001). The mean VAS pain scores of the lesions showed statistically significant differences between the follow-up periods compared to the baseline (P<0.001). The process was completely pain-free and required no anesthesia. After NTCLT, no kind of thermal adverse effects such as irritation, destruction, aggravation and even erythema were observed. Conclusion: Based on the results of this before-after clinical trial, NTCLT has the potential to be considered as a non-invasive and safe palliative option for the pain management of patchy OM due to chemotherapy of solid tumors.

Immediate Analgesic Effect of Non-thermal CO2 Laser Therapy (NTCLT) on Oral Ulcers in a Kidney Transplant Patient with Leukopenia

Introduction: The significant and immediate analgesic effect of Non-thermal CO2 Laser Therapy (NTCLT) as an efficient, safe, and innovative photobiomodulation (PBM) approach has been demonstrated in some painful oral lesions, such as recurrent oral aphthous ulcers, oral lesions of pemphigus vulgaris, and oral mucositis due to chemotherapy of solid tumors. Case Presentation: We report a case of a kidney recipient patient hospitalized due to pancytopenia, fever, and painful oral ulcers. According to the clinical features of the oral lesions and after extensive workups, drug-induced leucopenia, and the resultant leucopenia-induced oral ulceration were the most acceptable diagnoses for the patient. She was referred to our laser department for pain reduction of her painful oral ulcers by NTCLT. The CO2 laser (power: 1 watt) was irradiated through a thick layer of a completely transparent gel with very high water content while scanning the surface of the lesion with rapid circular motion of the defocused handpiece. Results and Conclusions: The pain of the patient's oral ulcer was relieved immediately and dramatically after NTCLT without any visible thermal side effects. The procedure was completely painless, and anesthesia was not required. The results of this report suggest that NTCLT can be considered a promising procedure for significant and instant pain relief of leucopenia-induced oral ulceration in kidney recipient patients without any thermal complications.