CO2 Laser Crystallization in Ambient for Highly Efficient FAPbI3 Perovskite Solar Cells

Metal halide perovskite solar cells have achieved tremendous progress and have attracted enormous research and development efforts since the first report of demonstration in 2009. Due to fabrication versatility, many heat treatment methods can be utilized to achieve perovskite film crystallization. Herein, 10.6 µm carbon dioxide laser process is successfully developed for the first time for perovskite film crystallization. In addition, this is the first time formamidinium lead triiodide solar cells by laser annealing under ambient are demonstrated. The champion cell produces a power conversion efficiency of 21.8%, the highest for laser-annealed perovskite cells. And this is achieved without any additive, passivation, or post-treatment.

Influence of scar age, laser type and laser treatment intervals on paediatric burn scars: a systematic review and meta-analysis

Background

Laser therapy has emerged to play a valuable role in the treatment of paediatric burn scars; however, there is heterogeneity in the literature, particularly concerning optimal timing for initiation of laser therapy. This study aims to investigate the effect of factors such as scar age, type of laser and laser treatment interval on burn scar outcomes in children by meta-analysis of previous studies.

Methods

A literature search was conducted across seven databases in May 2022 to understand the effects of laser therapy on burn scar outcomes in paediatric patients by metanalysis of standardized mean difference (SMD) between pre- and post-laser intervention. Meta-analyses were performed using the Comprehensive Meta-Analysis software version 4.0. Fixed models were selected when there was no significant heterogeneity, and the random effects model was selected for analysis when significant heterogeneity was identified. For all analyses, a p-value < 0.05 was considered significant.

Results

Seven studies were included in the meta-analysis with a total of 467 patients. Laser therapy significantly improved Vancouver Scar Scale (VSS)/Total Patient and Observer Scar Assessment Scale (Total POSAS), vascularity, pliability, pigmentation and scar height of burn scars. Significant heterogeneity was found between the studies and thus subgroup analyses were performed. Early laser therapy (<12 months post-injury) significantly improved VSS/POSAS scores compared to latent therapy (>12 months post-injury) {SMD -1.97 [95% confidence interval (CI) = -3.08; -0.87], p < 0.001 vs -0.59 [95%CI = -1.10; -0.07], p = 0.03} as well as vascularity {SMD -3.95 [95%CI = -4.38; -3.53], p < 0.001 vs -0.48 [95%CI = -0.66; -0.30], p < 0.001}. Non-ablative laser was most effective, significantly reducing VSS/POSAS, vascularity, pliability and scar height outcomes compared to ablative, pulse dye laser and a combination of ablative and pulse dye laser. Shorter treatment intervals of <4 weeks significantly reduced VSS/POSAS and scar height outcomes compared to intervals of 4 to 6 weeks.

Conclusions

Efficacy of laser therapy in the paediatric population is influenced by scar age, type of laser and interval between laser therapy application. The result of this study particularly challenges the currently accepted initiation time for laser treatment. Significant heterogeneity was observed within the studies, which suggests the need to explore other confounding factors influencing burn scar outcomes after laser therapy.

Scar Therapy of Skin

Scar therapy is truly important in medicine. Patients experience great loss in quality of life with scars. There are many treatment modalities that help treat scars, including topical, intralesional, surgical, and energy-based devices. In addition, early intervention can help mitigate scar formation. Lasers represent a major innovation in the treatment of all types of scars. Treating scars is a multimodal and multispecialty endeavor. This article highlights the use of many therapies to treat scars and scar symptoms including pruritus, pain, and range of motion. This also highlights key literature including multiple recent consensus guidelines in treating scars.

Optimal Timing of Fractional CO 2 Laser on Cleft Lip Scars: A Single-Blind Randomized Controlled Cohort Study

OBJECTIVE

To determine the optimal time to apply a fractional CO 2 laser for the treatment of postsecondary repair scars in patients with cleft lip.

METHODS

Forty-two patients with linear scarring after cleft lip repair were recruited from November 2021 to October 2022. A single-blind, randomized, controlled cohort study was conducted to examine the impact of fractional CO 2 laser treatment compared with conventional conservative treatment. Thirty patients started laser treatment at 1 month ( n = 10), 3 months ( n = 10), and 6 months ( n = 10) postoperatively, and 12 patients were in the control group. Each patient was treated with high-energy low-density fractional CO 2 laser treatment 3 times at an interval of 1 month. The Vancouver Scar Scale (VSS) was used for scar evaluation to determine vascularity, pigmentation, pliability, and height.

RESULTS

The VSS scores decreased significantly after laser treatment ( p < .05), with the most significant improvement in scars in the group that started treatment 1 month after the surgery.

CONCLUSION

Early postoperative fractional CO 2 laser treatment of cleft lip scars is more effective than later treatment.

A Single-Institution Experience About 10 Years With Children Undergoing Fractional Ablative Carbon Dioxide Laser Treatment After Burns: Measurement of Air Pressure-Induced Skin Elevation and Retraction Time (Dermalab) Including Standardized Subjective and Objective Scar Evaluation

Laser treatment has gained more and more importance in the therapy of scars during the last years. Scientific work, especially in children, is scarce on this topic and mostly with an insufficient number of cases or only subjective descriptions. Our study included 77 children from 2012 to 2022 with scars after thermal injury. These were treated at least three times or more by CO2 laser or in combination with pulsed dyed laser (PDL). Beforehand, scar texture and elasticity were determined by a skin elasticity analysis system. Regarding the subjective evaluation, a questionnaire was given to the patients or their parents. Further criteria were the Patient and Observer Scar Assessment Scale (POSAS) and Vancouver Scar Scale (VSS). A statistically significant improvement in elasticity was demonstrated in all scars of any age after each laser treatment. In addition, a significant correlation was found between the number of laser treatments and an increase in elasticity. The assessments of scars after one or more laser sessions by the observer as well as the patient showed a decreasing score in all categories with an increase in the number of laser therapies. The VSS score also improved significantly after each laser session. The mean score before treatment was about 7, after the first laser session, the mean score was already below 6 with a statistical significance. Ninety-six percent of the patients or their parents were satisfied with the laser therapy, and 90% wished to repeat the procedure. This work confirms, by means of the objectification by the scar measurement, the previous scientific works concerning a scar therapy by laser and emphasizes particularly that this can also be used without problems with children with symptomatic scars, contractures, or with cosmetically relevant scars.

Assessment of a 3050/3200 nm fiber laser system for ablative fractional laser treatments in dermatology

Background and Objectives

Mid‐infrared (IR) ablative fractional laser treatments are highly efficacious for improving the appearance of a variety of dermatological conditions such as photo‐aged skin. However, articulated arms are necessary to transmit the mid‐IR light to the skin, which restricts practicality and clinical use. Here, we have assessed and characterized a novel fiber laser‐pumped difference frequency generation (DFG) system that generates ablative fractional lesions and compared it to clinically and commercially available thulium fiber, Erbium:YAG (Er:YAG), and CO₂ lasers.

Materials and Methods

An investigational 20 W, 3050/3200 nm fiber laser pumped DFG system with a focused spot size of 91 µm was used to generate microscopic ablation arrays in ex vivo human skin. Several pulse energies (10–70 mJ) and pulse durations (2–14 ms) were applied and lesion dimensions were assessed histologically using nitro‐blue tetrazolium chloride stain. Ablation depths and coagulative thermal damage zones were analyzed across three additional laser systems.

Results

The investigational DFG system‐generated deep (>2 mm depth) and narrow (<100 µm diameter) ablative lesions surrounded by thermal coagulative zones of at least 20 µm thickness compared to 13, 40, and 320 µm by the Er:YAG, CO₂, and Thulium laser, respectively.

Conclusion

The DFG system is a small footprint device that offers a flexible fiber delivery system for ablative fractional laser treatments, thereby overcoming the requirement of an articulated arm in current commercially available ablative lasers. The depth and width of the ablated microcolumns and the extent of surrounding coagulation can be controlled; this concept can be used to design new treatment procedures for specific indications. Clinical improvements and safety are not the subject of this study and need to be explored with in vivo clinical studies.

Effects of multiple modes of UltraPulse fractional CO2 laser treatment on extensive scarring: a retrospective study

The main therapeutic options for extensive scarring (e.g., > 20% of the total body surface area, or TBSA) after burns and trauma have focused on conservative treatments, such as compression, moisturization, and topical agent application. However, these treatments may not achieve optimal effects due to the large size and complexity of the scars. UltraPulse fractional CO₂ laser treatment is a novel approach that is currently a subject of intense interest; this treatment is most widely used to improve texture, pliability, and pigmentation in all types of scars. However, no studies on the independent use of UltraPulse fractional CO₂ laser treatment for extensive scars have been reported. This retrospective study evaluated a total of 21 patients, whose scars covered 20 to 65% TBSA. Scar thickness was measured by ultrasonography before treatment. Personalized treatment modalities and parameters were set according to the scar type and thickness. Scar formation and treatment effects were evaluated by photography, the Patient and Observer Scar Assessment Scale (POSAS), and patients’ judgment of effectiveness. Where the scars covered joints, joint function was assessed by measuring the maximum range of motion (ROM). With laser therapy, scars became flatter and lighter; furthermore, pruritus, pain, and discomfort decreased significantly. POSAS scores significantly decreased after laser therapy, including the item scores for pain and pruritus. There were no instances of joint contracture, ROM reduction, apparent functional impairment, serious adverse events, or comorbidities. This study demonstrates the safety and efficiency of UltraPulse fractional CO₂ laser treatment for extensive scarring.

Hypertrophic Scar Improvement by Early Intervention With Ablative Fractional Carbon Dioxide Laser Treatment

BACKGROUND AND OBJECTIVES

Ablative fractional laser treatment has been used to improve the color and texture of hypertrophic scars with safe and effective results. However, no consensus on the optimal time to initiate fractional laser treatment is available. The effect on early-stage scars remains controversial. This study was designed to assess the efficacy and safety of ablative fractional carbon dioxide (CO₂ ) laser treatments for hypertrophic burn scars and to analyze the efficacy and safety in the early period within 3 months after injury.

STUDY DESIGN/MATERIALS AND METHODS

We performed a retrospective study of 221 hypertrophic scar patients. According to the time of the first laser treatment after injury, patients were divided into five subgroups, including less than 1 month, 1-3 months, 3-6 months, 6-12 months, and more than 12 months postinjury. One month after the last laser treatment, the scars were assessed by photography, the Vancouver Scar Scale (VSS), durometry, and spectrocolorimetry.

RESULTS

The patients included 118 males and 103 females. The average age was 33.6 years. Fire/flame was the primary injury source. Thirty-six percent of the patients underwent at least one fractional CO₂ laser treatment. All the included patients, including those treated within 1 month after injury, had significantly decreased VSS scores after laser treatment. We also noted that hardness and redness scores were decreased after treatment for both scars treated within 3 months and those treated more than 12 months after injury. Seepage (17.6%), bleeding (22.2%), and swelling (9.0%) were the main adverse events after laser treatment.

CONCLUSIONS

This study demonstrated the safety and efficacy of ablative fractional CO₂ laser treatment applied to early-stage burn scars. The optimal time for laser application for burn patients can be within 1 month after injury. Durometry and spectrocolorimetry were effective for assessing scars as objective modalities. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

Evaluation of the Efficacy of Ultrapulsed CO2 Laser in Chronic Wounds

BACKGROUND AND OBJECTIVES

Chronic wound repair is a major problem in wound treatment. Recently, several studies have suggested that carbon dioxide (CO₂ ) laser can be used to improve the healing of chronic wounds. The aim of the present study was to preliminarily investigate the efficacy of laser debridement in treating chronic wound through a comparison of traditional instrument/surgical debridement with the ultrapulsed CO₂ laser debridement in terms of wound healing, wound infection control, and wound blood perfusion.

STUDY DESIGN/MATERIALS AND METHODS

Patients with chronic wound admitted to the Wound Repair Clinic at The Affiliated Hospital of Southwest Medical University (Luzhou, China) between February 2019 and May 2019 were enrolled. They were randomly divided into two groups. The patients in one group were treated with traditional sharp instrument/surgical debridement (RT group; number of wounds: 28), while the patients in the other group were treated with ultrapulsed CO₂ laser debridement (LT group; number of wounds: 26). An intergroup comparison was performed based on parameters, such as wound healing, wound infection control, and changes in wound blood perfusion.

RESULTS

The wound healing rate and the total time to achieve healing were significantly better in the LT group versus the RT group at 7, 14, 21, and 28 days after treatment. The wound exudation scores were significantly higher in the LT group versus the RT group at 7, 14, and 28 days after treatment. The positive rate of pre-debridement bacterial culture was significantly lower in the LT group versus the RD group at 14 and 28 days after treatment. The percentage of wound perfusion/normal periwound skin perfusion was significantly higher in the LT group versus the RT group at 1, 7, and 14 days after treatment.

CONCLUSION

For the treatment of chronic refractory wounds, the ultrapulsed CO₂ laser exhibits higher accuracy, more effectively controls wound infection, promotes an increase in wound blood perfusion, and achieves faster wound healing compared with traditional sharp instrument/surgical debridement. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.

3D Mesh Releasing Method: A Retrospective Analysis of Fractional CO2 Treatment on Contracture Scars

BACKGROUND AND OBJECTIVES

There has been reports on fractional CO₂ laser successfully improving contracture scars that impair the function of a joint. It seems that certain contracture problems could be solved by laser instead of surgery. However, the clinical application could be difficult when the efficacy of the method remains unknown. The purpose of this study is to report the releasing capacity of the fractional CO₂ laser on contracture scars based on a defined treatment method.

STUDY DESIGN/MATERIALS AND METHODS

We conducted a retrospective study in patients with limited function in joints caused by contracture scars. Fractional CO₂ laser and our "3D mesh releasing" protocol were applied. The primary outcome was the improvement measured in range of motion (ROM) of the relevant joint before all intervention and 6 months after the last treatment.

RESULT

From November 2016 to January 2018, 11 joints of 10 cases were treated by the fractional CO₂ laser. Patients went through 2.27 (standard deviation [SD] 1.42, 1-5) sessions. The average progress of ROM before and 6 months after all treatments was 19.13° (SD 10.25, P < 0.02). In six cases, we recorded that there was an 8.53° (SD 5.81, P < 0.02) of increase in ROM immediately after the laser session, and the average improvement reached up to 13.58° (SD 8.15, P < 0.02) after 2-3 months during the next follow-up.

CONCLUSION

The fractional CO₂ laser could achieve functional improvement in contracture scars and it maintained its effect for at least 6 months. The "3D Mesh Releasing" protocol would help to standardize the treatment procedure. This modality has minimal-invasiveness and potentially could become a supplement to the current treatment choices for mild contracture scars. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.