CO2 Laser Research Articles

Efficacy of a Combination Treatment of Ablative Fractional Carbon Dioxide Laser Therapy and Recombinant Human Epidermal Growth Factor for Atrophic Acne Scars.

Atrophic acne scars (AAS) are disfiguring and permanent changes caused by inflammatory acne. Fractional carbon dioxide is a common ablative device used to treat this condition. However, issues such as unclear effectiveness, frequent treatments, and potential side effects exist. In recent years, recombinant human epidermal growth factor (rhEGF) has also been frequently reported for its application in the treatment of acne scars. To explore the potential synergistic effect of fractional carbon dioxide laser combined with rhEGF in AAS treatment. We enrolled 15 patients with AAS. They received fractional carbon dioxide laser treatment and were then randomly assigned to receive either rhEGF or a placebo on one side of the face. The procedure was repeated three times, and the results were evaluated using the échelle d'évaluation clinique des cicatrices d'acné (ECCA) score and analyzed using the CBS camera system, 3D analysis (3DMD). Reflectance confocal microscopy (RCM) examination was also conducted. Both sides exhibited significant improvement in the appearance of the acne scars after treatment, as confirmed by the ECCA score, 3DMD data, and CBS texture score. On the rhEGF-treated side, the pore number and epidermal pigment area significantly improved as compared to the control side, whereas no significant differences were observed in the other data. Under RCM, a significant increase in epidermal thickness and appearance of reticular collagen fibers in the dermal layer after treatment was observed. Compared to the sole use of laser, the combination of fractional carbon dioxide laser and rhEGF does not significantly enhance scar therapeutic effects. However, it does shorten the recovery period after laser treatment and improves the pore appearance.

A Simultaneous Measurement Sensor for Temperature and Curvature Based on Congruent Quasi-Helical Long-Period Fiber Grating.

This article presents a long-period fiber-grating sensor based on a congruent quasi-helical structure (CQH-LPFG) with the two-parameter measurement of both temperature and curvature. The CQH-LPFG sensor was manufactured using a high-frequency CO2 laser, and an innovative quasi-helical structure was introduced into the two-parameter measurement of the temperature and curvature of the optical fiber sensor with excellent results. The experiment and analysis demonstrate that the curvature sensitivities of the three resonance peaks in the 1440 nm to 1540 nm transmission spectrum were 11.88 nm/m-1, 8.05 nm/m-1, and 11.11 nm/m-1, and the curvature varied ranging from 0.156 m-1 to 0.494 m-1. The three resonance peaks showed temperature responsivities of 29.87 pm/°C, 24.65 pm/°C, and 36.85 pm/°C, respectively, and the linear fit was of excellent quality. In the case of measuring both curvature and temperature changes simultaneously, the resonant peak wavelength of the CQH-LPFG sensor was demodulated through matrix analysis, with dip A and dip C providing superior simultaneous measurements. These features make it a promising candidate for applications such as engineering machinery and the health inspection of buildings.

Evaluation of Skin Recovery after Fractional CO2 Laser Treatment of Vulvar Lichen Sclerosus Using Multimodal Optical Coherence Tomography

Evaluation of Skin Recovery after Fractional CO2 Laser Treatment of Vulvar Lichen Sclerosus Using Multimodal Optical Coherence Tomography

Comparative study in treatment of acne scars fractional carbon dioxide laser versus micro needling fractional radio frequency – A retrospective study

Objectives: Efficacy of fractional carbon dioxide laser and microfractional radiofrequency in treatment of acne scars is well substantiated. The objective of this study was to compare the efficacy and safety of carbon dioxide laser versus microfractional radiofrequency in treatment of acne scars in skin type 3,4. Material and Methods: Thirty-two patients of skin types 3–4 with grade 3 and 4 atrophic acne scars, of which 16 were treated with fractional carbon dioxide (CO2) laser and 16 were treated with microfractional radiofrequency were retrospectively analyzed. All patients received either treatment 4 sessions at an interval of 4–6 weeks. Objective assessment was done with qualitative and quantitative Goodman and baron acne scar grading system by assessment of photographs at baseline and 3 months after last session. Results: All the data collected were entered in a Microsoft Excel worksheet and analyzed using R Software R-4.2.1. The study variables acne scar grades were described using frequency with percentage, acne scar scores were described using Mean with Standard deviation, and Median with interquartile range (IQR) (Q1-Q3). Since the data were ordinal, which is non-normal, hence, non-parametric tests are applied. To compare grades between the groups, Mann–Whitney U-test was applied. Conclusion: There was no difference in the last session (after the treatment) between the groups, the Mann– Whitney U-test was 109.5 with P-value of 0.484 >0.05. Therefore, there was no statistically significant difference between the microfractional radiofrequency and carbon dioxide laser group. There were 2 (12.5%) cases reported with post-inflammatory hyperpigmentation in the CO2 laser group and zero cases in the microfractional radiofrequency group.

Efficacy of fractional carbon dioxide laser-assisted drug delivery in the management of post-burn scars – A prospective study

Objectives: The objective of our study is to assess the efficacy of fractional carbon dioxide (CO2) laser-assisted drug delivery (LADD) in the management of post-burn scars. Material and Methods: It is a prospective study conducted from March 2021 to February 2022, with 32 patients ranging in age from 9 to 52 years. The scars lasted anywhere from 6 months to 18 years. The ethical clearance of the Institutional Ethics Committee was obtained. The patient’s median age was 22 (range, 09–52). Patients were assessed using a modified Vancouver scar scale (mVSS) score before and after receiving fractional CO2 laser at monthly intervals. Results: After one treatment, statistically significant improvements in pigment, thickness, and pliability were seen according to the mVSS scores, and these improvements persisted through the final laser session. Conclusion: Our study has demonstrated that fractional CO2 LADD seems to be an encouraging approach in the management of post-burn scars with good patient satisfaction.

Melt Pool Flow Dynamics of Copper Imbued Surface Alloyed 304 Stainless Steel: Role of Laser Power and Scanning Speed Tuning

This study emphasizes the crucial role of Marangoni convection in the laser surface-alloying of 304 stainless steel (304 SS) with copper (Cu). By studying the microscopic behavior of the melt pool during CO2 laser alloying, the study reveals the association between Marangoni convection and the resulting microstructure. The findings demonstrate that the most optimum deposited track can be observed at power 80 W with a scanning speed of 0.4950 mm/s while the highest scanning speed of 0.6329 mm/s produced the finest grains. From the microhardness analysis, sample with the scanning speed of 0.6329 mm/s yielded the best microhardness due to fast cooling and solidification, highlighting the importance of controlling the process parameters to achieve the desired outcome. This data provides valuable insights into the laser-matter interaction and underscores the need to understand underlying melt pool flow dynamics mechanisms such as Marangoni convection to optimize the process for high-quality results.

Additive manufacturing of quartz glass using coaxial wire feeding technology

This study explores the process of coaxial wire feeding and melting for quartz additive manufacturing using Direct Energy Deposition (DED). Quartz glass, valued for its excellent mechanical, optical, and thermal properties, is widely used in semiconductor, aerospace, and optical communication industries. Additive manufacturing offers advantages such as cost-effective materials, rapid formation, and customization of structures. However, current methods for additive manufacturing of quartz glass often result in low quality or require complex post-processing, particularly for optical components. In optics, there is a demand for high-quality, straightforward processes, and custom-shaped quartz glass. This article presents a coaxial wire feeding mechanism wherein quartz wire is fed vertically downward along the optical axis into the melting zone created by a CO2 laser, facilitating smooth material deposition onto the molten zone’s surface. Laser power, wire feeding speed, substrate movement speed, and defocusing distance are key factors influencing the quality of single-layer quartz glass formation. Positive defocusing was found to have a beneficial impact on single-layer quartz glass additive manufacturing. Subsequently, optimized process parameters enabled the production of uniformly cross-sectional single-layer quartz glass. Microscopic morphology analysis and temperature field simulation were conducted on the experimental results before and after optimization. Finally, complex quartz glass structures were additively manufactured using the optimized experimental parameters. Results demonstrate that coaxial wire feeding technology has significant potential for achieving uniform dimensions and complex structures in quartz glass additive manufacturing.

Thin Film of Poly-peri-naphthalene (PPN) Fabricated by Direct Laser Writing and Its Use for Humidity Sensing.

Inspired by the versatility of the direct laser writing carbonization (DLWc) technique as well as the metal-ion-assisted coordination polymer of 3,4,9,10-perylene tetracarboxylic dianhydride (PTCDA), in the present study, we present a DLWc-enabled approach for cost-effectively fabricating a poly-peri-naphthalene (PPN) thin film with the advantages of patternability, environmental benignity, and scalability. Optical and scanning electron microscopy, as well as ultraviolet-visible-near-infrared, Fourier transform infrared, Raman, and X-ray photoelectron spectroscopies, were performed to confirm that the spray-coated thin film of the Mg-PTCDA coordination polymer can be in situ converted into a PPN thin film upon CO2 laser irradiation. The effects of the laser power and Mg2+ concentration on the structure and electrical properties of the laser-processed PPN thin films were investigated. Lastly, we demonstrated that the laser-processed PPN thin films can be used for humidity sensing with characteristics of a rapid response time and excellent hysteresis. It is expected that this new method for fabricating PPN thin films will lead to a wide range of applications of PPN in the fields of sensing, electronics, and energy storage.

Exceptional fabrication of dead-weight-free silicon and graphitic heterostructures anodes for the next advancement of Li-ion batteries

Silicon (Si)-graphite and graphite (without Si) anodes for Li-ion batteries are developed at ambient conditions through the direct irradiation of CO2 laser, resulting in avoiding the use of binders, conductive carbon additives, and organic and water-based solvents. Furfuryl alcohol (FA) is mixed with Si-graphite and graphite, prepared viscous slurry through the heating, cast on the copper foil, and dried. Irradiation of CO2 laser at the electrode of Si-graphite-FA generates in-situ hetero-structures of Si particles, SiC/Si-SiC nanowires made of spontaneously carbon-coated/oxidized nano-layer (∼ 3nm), and graphitic carbon containing few layers of graphene. All the laser-fabricated electrode material is electrochemically active (∼ 0% dead weight) in the Si-graphite and graphite anodes since the FA converts to the graphitic carbon containing few layers of graphene; thus, the fabrication method could benefit the next industrial development. The discharge capacity of the Si-graphite electrode with total material loading is recorded at 502.2 mAh/g (∼ 1.9 mAh cm−2) and capacity retention of ∼ 80 % over the 50 cycles vs. Li/Li+. Also, it shows good discharge capacity when fabricated with NMC622 in full-cell format. Therefore, this performance is highly stable without any binder and conductive carbon, especially for Si-based battery, which fails rapidly due to substantial volume changes (∼ 300 %). Moreover, the performance is highly stable for graphite anode with a discharge capacity retention of 91 % over the 160 cycles as considered 100 % (∼ 345 mAh/g) after the formation cycle.

Highly Sensitive and Flexible Capacitive Pressure Sensors Combined with Porous Structure and Hole Array Using Sacrificial Templates and Laser Ablation.

Flexible, wearable pressure sensors offer numerous benefits, including superior sensing capabilities, a lightweight and compact design, and exceptional conformal properties, making them highly sought after in various applications including medical monitoring, human-computer interactions, and electronic skins. Because of their excellent characteristics, such as simple fabrication, low power consumption, and short response time, capacitive pressure sensors have received widespread attention. As a flexible polymer material, polydimethylsiloxane (PDMS) is widely used in the preparation of dielectric layers for capacitive pressure sensors. The Young's modulus of the flexible polymer can be effectively decreased through the synergistic application of sacrificial template and laser ablation techniques, thereby improving the functionality of capacitive pressure sensors. In this study, a novel sensor was introduced. Its dielectric layer was developed through a series of processes, including the use of a sacrificial template method using NaCl microparticles and subsequent CO2 laser ablation. This porous PDMS dielectric layer, featuring an array of holes, was then sandwiched between two flexible electrodes to create a capacitive pressure sensor. The sensor demonstrates a sensitivity of 0.694 kPa-1 within the pressure range of 0-1 kPa and can effectively detect pressures ranging from 3 Pa to 200 kPa. The sensor demonstrates stability for up to 500 cycles, with a rapid response time of 96 ms and a recovery time of 118 ms, coupled with a low hysteresis of 6.8%. Furthermore, our testing indicates that the sensor possesses limitless potential for use in detecting human physiological activities and delivering signals.

Investigations of the Laser Ablation Mechanism of PMMA Microchannels Using Single-Pass and Multi-Pass Laser Scans.

CO2 laser machining is a cost effective and time saving solution for fabricating microchannels on polymethylmethacrylate (PMMA). Due to the lack of research on the incubation effect and ablation behavior of PMMA under high-power laser irradiation, predictions of the microchannel profile are limited. In this study, the ablation process and mechanism of a continuous CO2 laser machining process on microchannel production in PMMA in single-pass and multi-pass laser scan modes are investigated. It is found that a higher laser energy density of a single pass causes a lower ablation threshold. The ablated surface can be divided into three regions: the ablation zone, the incubation zone, and the virgin zone. The PMMA ablation process is mainly attributed to the thermal decomposition reactions and the splashing of molten polymer. The depth, width, aspect ratio, volume ablation rate, and mass ablation rate of the channel increase as the laser scanning speed decreases and the number of laser scans increases. The differences in ablation results obtained under the same total laser energy density using different scan modes are attributed to the incubation effect, which is caused by the thermal deposition of laser energy in the polymer. Finally, an optimized simulation model that is used to solve the problem of a channel width greater than spot diameter is proposed. The error percentage between the experimental and simulation results varies from 0.44% to 5.9%.

Utility of prostaglandin analogues and phosphodiesterase inhibitors as promising last resorts for the treatment of vitiligo: A systematic review, from mechanisms of action to mono-, combination and comparative therapies.

The treatment of vitiligo is a persistent challenge in dermatology. New treatments are being offered and studied in this field for those resistant to or intolerant of classical therapies. In this systematic review, we study the use of prostaglandin analogues (PGAs) and phosphodiesterase inhibitors (PDEIs) in the treatment of vitiligo, as they are known for their pigmentation inducing effects through activating melanocytes. We searched four main online databases with the keywords "Vitiligo", "Prostaglandin analogue" and "Phosphodiesterase inhibitor". A total of 42 articles were included, with 1027 cases, studying drugs like bimatoprost, latanoprost, travoprost, dinoprostone, apremilast, crisaborole, etc. Among the included studies, the treatment regimens are commonly once or twice daily for 12-48 weeks, with a mean of 20.61 weeks, and the routes of administration are mainly topical gels or ophthalmic solutions and oral tablets. Side effects are mild and tolerable, namely erythema, itching or burning sensations at application site for topicals, or gastrointestinal problems with apremilast. Repigmentation results are significant in both adult and pediatric patients and progressive or stable vitiligo. PGAs and PDEIs outperform many classical therapies, for example, narrowband ultraviolet B phototherapy (NB-UVB), tacrolimus, mometasone or methylprednisolone mini-pulse. PGAs or PDEIs are usually used in combination therapies to either cause synergism or increase drug delivery, and almost always enhance repigmentation, for example, with NB-UVB, fractional CO2 laser, microneedling, and mometasone. Monotherapy or add-on PGAs and PDEIs can be considered effective treatments for vitiligo and promising last resorts for those resistant to other therapies.

Machine Learning Based Surface Finish Prediction and Optimization of Process Parameters in Pulsed CO2 Laser Cutting of Particle (TiC) Reinforced Al6061 Composite Using KNN & ANN

Machine Learning Based Surface Finish Prediction and Optimization of Process Parameters in Pulsed CO2 Laser Cutting of Particle (TiC) Reinforced Al6061 Composite Using KNN & ANN

Successful Treatment of Darier-White Disease with Ablative Fractional Carbon Dioxide Laser.

Successful Treatment of Darier-White Disease with Ablative Fractional Carbon Dioxide Laser.

Advances in the Management of Localized Scleroderma: A Systematic Review of Laser Therapy and Injectable Filler Approaches.

Localized scleroderma (LS), commonly known as morphea, presents a significant clinical challenge due to its chronic, inflammatory nature affecting the skin and potentially underlying tissues. This systematic review explores the innovative approach of combining laser therapy and injectable fillers, specifically hyaluronic acid, for the treatment of LS. We conducted a comprehensive literature review following PRISMA guidelines, examining articles from MEDLINE/PubMed to assess the combined efficacy of these treatments in improving both esthetic and functional outcomes for LS patients. The search yielded 64 articles, with six selected for in-depth analysis for a total of nine patients, covering a range of patient demographics and treatment types. Our review highlights cases where fractional CO2 laser therapy promoted long-term tissue remodeling and instances where hyaluronic acid fillers effectively addressed skin atrophy and volume loss, enhancing both immediate and long-lasting esthetic improvements. The synergy between these treatments suggests a promising dual approach, aiming to maximize esthetic outcomes and to improve the quality of life for LS patients. This review underscores the necessity of further research to establish a comprehensive, evidence-based clinical pathway integrating both treatments for managing LS, thereby enhancing patient satisfaction and addressing the multifaceted nature of this challenging dermatological condition.

One-Step Fabrication of Composite Hydrophobic Electrically Heated Graphene Surface

Ice accumulation poses considerable challenges in transportation, notably in the domain of general aviation. The present study combines the strengths and limitations of conventional aircraft deicing techniques with the emerging trend toward all-electric aircraft. This study aims to utilize laser-induced graphene (LIG) technology to create a multifunctional surface, seamlessly integrating hydrophobic properties with efficient electrical heating to mitigate surface icing effectively. We investigated the utilization of a 10.6 μm CO2 laser for direct writing on polyimide (PI), a widely used insulating encapsulation material. From the thermomechanical perspective, our initial analysis using COMSOL Multiphysics software (V5.6) revealed that when the laser power P exceeds 5 W, the PI substrate experiences ablative damage. The experimental results show that when P ≤ 5 W, an increase in power has a positive impact on the quality, surface porosity, roughness reduction, line-spacing reduction, and water contact-angle enhancement of the graphene. Conversely, when P > 5 W, higher power negatively affects both the substrate and the graphene structure by inducing excessive ablation. However, it influences the graphene line height positively and is consistent with overall experimental–simulation congruence. Furthermore, the incorporation of high-quality graphene resulted in a surface that exhibited higher contact angles (CA > 120°), lower energy consumption, and higher heating efficiency compared to the use of traditional electrically heated materials for anti-icing applications. The potential applications of this one-step fabrication method extend across various industries, particularly aviation, marine engineering, and other ice-prone domains. Moreover, the method has extensive prospects for addressing pivotal challenges associated with ice formation and serves as an innovative and efficient anti-icing technology.

Optical properties of transparent TiO2 films by sintering anatase nanoparticles with a CO2 laser

A novel CO2 laser additive manufacturing technique is reported in this paper for depositing transparent TiO2 films on quartz substrates using anatase TiO2 nanoparticles (NPs). Single- and double-layers of TiO2 films were prepared in two stages: (i) wet deposition using the spin-coating technique, and (ii) laser-assisted both drying of the wet layer and then sintering of the dried NPs to form a film. A theoretical model is presented to select and optimize the laser processing parameters. Scanning electron microscopy (SEM) revealed that the laser heating induces necking and coalescence of TiO2 NPs without cracking the sintered films or damaging the quartz substrate. An anti-reflection coating (ARC) model is utilized to select the film material and film thickness, aiming to reduce the reflectance and enhance the transmittance at certain wavelengths. UV/Vis spectrophotometry showed transmittance above ∼90% in the visible (Vis) range. The effect of laser power on the enhancement of transmittance is presented in this paper. Different concentrations of TiO2 NPs were used to optimize the film thickness. Single layer (∼110nm thick) and double layer films of the same total thickness as the single layer were analyzed to infer the effects of interface on the transmittance of TiO2 films. The transmittance of the single layer is higher, same as that of the double layer. Therefore, the difference in the transmittance of the single- and double-layer may be due to the effect of interface. The optical properties of the anti-reflection TiO2 coating in the UV–Vis ranges were investigated. X-ray diffraction (XRD) analysis showed that the thickness affects the crystallinity of the sintered TiO2 films.

Spacing mode multi-wavelength erbium doped fiber laser based on a symmetrical long-period fiber grating

We present a multiwavelength erbium-doped fiber laser based on a symmetrical long-period fiber grating (LPFG) with tunable spacing mode between single lasing mode and multiwavelength spectra. The LPFG was manufactured using a thermal expansion technique using an LZM-100 glass processing system equipped with a CO2 laser, and it was used as a wavelength-selective filter (WSF) in the laser ring cavity. The laser can emit single, double, triple, quadruple, quintuple, or sextuple lines in the range from 1546 to 1563 nm, which can be tunable by controlling the radius of curvature of the LPFG in the range 0–0.2662 m −1. A minimal spacing mode of 1.92 nm was observed in the multiwavelength region; meanwhile, the fiber laser offers an average spacing mode of 6.945 nm between the multiwavelength region and the single emission. This laser has a 3 dB linewidth of 0.11 nm and a side mode suppression ratio (SMSR) of 55.56 dB. Finally, according to experimental results, the laser has high wavelength stability at room temperature for 88 min.

Effects of “blue” (λ = 450 nm) and pulsed periodic CO2 (λ = 10.6 μm) laser light at the skin of laboratory animals. A comparative experimental study

Effects of “blue” (λ = 450 nm) and pulsed periodic CO2 (λ = 10.6 μm) laser light at the skin of laboratory animals. A comparative experimental study

Mitigating Intraphase Catalytic-Domain Transfer via CO2 Laser for Enhanced Nitrate-to-Ammonia Electroconversion and Zn-Nitrate Battery Behavior.

Developing sustainable energy solutions is critical for addressing the dual challenges of energy demand and environmental impact. In this study, a zinc-nitrate (Zn-NO3-) battery system was designed for the simultaneous production of ammonia (NH3) via the electrocatalytic NO3- reduction reaction (NO3RR) and electricity generation. Continuous wave CO2laser irradiation yielded precisely controlled CoFe2O4@nitrogen-doped carbon (CoFe2O4@NC) hollow nanocubes from CoFe Prussian blue analogs (CoFe-PBA) as the integral electrocatalyst for NO3RR in 1.0-M KOH, achieving a remarkable NH3 production rate of 10.9 mgh-1cm-2 at -0.47 V versus RHE with exceptional stability. In-situ and ex-situ methods revealed that the CoFe2O4@NC surface transformed into high-valent Fe/CoOOH active-species, optimizing the adsorption energy of NO3RR (*NO2 and *NO species) intermediates. Furthermore, DFT calculations validated the possible NO3RR pathway on CoFe2O4@NC starting with NO3- conversion to *NO2 intermediates, followed by reduction to *NO. Subsequent protonation forms the *NH and *NH2 species, leading to NH3 formation via final protonation. The Zn-NO3- battery utilizing the CoFe2O4@NC cathode exhibits dual functionality by generating electricity with a stable open-circuit voltage of 1.38-V versus Zn/Zn2+ and producing NH3. This study inspires the simple design of low-cost catalysts for NO3RR-to-NH3 conversion and positions the Zn-NO3- battery as a promising technology for industrial applications.