1064-nm Picosecond Research Articles

1064-nm Picosecond Laser Treatment for Hydroxychloroquine-Induced Hyperpigmentation of the Lower Extremities.

1064-nm Picosecond Laser Treatment for Hydroxychloroquine-Induced Hyperpigmentation of the Lower Extremities.

Comparison of the efficacy and safety of a 730-nm picosecond titanium sapphire laser and a 1064-nm picosecond neodymium yttrium aluminum garnet laser for the treatment of acquired bilateral nevus of Ota-like macules: A split-face, evaluator-blinded, randomized, and controlled pilot trial.

The picosecond neodymium yttrium aluminum garnet laser (PNYL) has been successfully used in treating acquired bilateral nevus of Ota-like macules (ABNOM). The 730-nm picosecond titanium sapphire laser (PTSL) is an emerging tool for pigmentary disorders. However, no studies have compared two different wavelengths of picosecond laser for the treatment of ABNOM. To compare the efficacy and safety of the 730-nm PTSL with the 1064-nm PNYL in the treatment of ABNOM. Fifteen participants with ABNOM were randomized to undergo a single session of either the 730-nm PTSL on one side of the face and 1064-nm PNYL on the other side. Efficacy and safety assessments were performed by blinded visual evaluations at baseline, 12 weeks, and 24 weeks posttreatment. Participants' satisfaction and adverse effects were recorded. Compared to baseline, The 730-nm PTSL-treated side showed better improvement than that of the 1064-nm PNYL-treated side at 24 weeks posttreatment (1.67 ± 1.047 vs. 0.87 ± 0.640, p = 0.027). There were no significant differences in pain sensation and participants' satisfaction between the two laser treatments. The 730-nm PTSL is more effective than the 1064-nm PNYL in the treatment of ABNOM.

The treatment of infantile giant café au lait spot using golden parameter therapy with a high fluence 1064-nm Q-switched Nd: YAG laser

Background Infantile café au lait spot is a brown macule with various sizes (diameter: 0.5 cm–30 cm). Infantile giant café au lait spot (IGCALS) is a huge (diameter >20cm) irregular-shaped benign hyperpigmented skin disorder that arises in infants. There has been no clearly established laser treatment consensus for the treatment of IGCALS because infants are too fragile to receive laser treatment with long hours and broad areas along with the possibility of undesirable cosmetic results. Objectives This study investigated the safety and efficacy of Golden Parameter Therapy (GPT) using a high fluence 1064-nm Q-switched Nd:YAG laser (QSNL) for IGCALS treatment. Methods This study included 24 Korean patients with IGCALS. Twenty-one patients who were treated with a 1064-nm QSNL weekly for 30–50 treatment sessions with GPT. The parameters included a spot size of 7 mm, a fluence of 2.2 J/cm2 and a pulse rate of 10 Hz with one pass using a sliding-stacking technique over the IGCALS. In control group, three patients were treated with a 532-nm picosecond laser monthly for three treatment sessions with a spot size of 3 mm, a fluence of 1 J/cm2 and a pulse rate of 2 Hz. Results After the last treatment, 21 patients with IGCALS reached the complete removal of pigmented lesions, which can be considered optimal cosmetic results without any side effects such as purpura, crust, post-inflammatory hyperpigmentation, iatrogenic punctate leukoderma, and scarring. There are no recurrences in any patients after 6–21 months’ follow-up, but treatment failure occurred in three patients who were treated with 532 nm picosecond laser. Conclusions Convincingly, we argue that early intervention before 12 months of age with GPT using a high fluence 1064 nm QSNL is a safe, applicable and effective treatment for IGCALS, minimizing side effects without any recurrences.

Exploring Fractional Pigment Toning: A Novel Approach for Treating Benign Pigmented Lesions in Asian Patients With Fitzpatrick Skin Types III-V.

Laser therapy has emerged as a widely favored treatment option for solar lentigines (SL). However, a significant challenge associated with this treatment, particularly among individuals with darker skin tones, is the notable risk of postinflammatory hyperpigmentation (PIH) induction. In response to these concerns, the authors conducted a prospective, self-controlled study to comprehensively evaluate the safety and effectiveness of 532-nm picosecond laser, both with and without a microlens array (MLA), for the management of SL in patients with Fitzpatrick skin types (FST) III-V. Twenty-seven patients with FST III-V and bilateral SL on the face underwent randomized treatment. One side of the face was treated with a 532-nm picosecond laser coupled with an MLA, utilizing the fractional pigment toning (FPT) technique, while the other side received treatment without the MLA, following the conventional technique (CT). The FPT technique utilized a 9-mm spot size with a fluence of 0.47 J/cm2 for two passes covering 40% of the area. In contrast, the CT used a 4.5-mm handpiece with fluence ranging from 0.3 to 0.7 J/cm2. Patients received a single treatment and were evaluated for pigment clearance, occurrence of PIH, and other adverse effects at 2 weeks, 1, 3, and 6 months posttreatment. Twenty-seven participants completed the study protocol. Analysis of pigment clearance, measured via 3D photography, showed significant improvement from 2 weeks to 6 months posttreatment for both the FPT technique (p < 0.001) and CT (p = 0.004). PIH occurred in 64%, 80%, 96%, and 88% of cases on the CT side, compared to 8%, 32%, 36%, and 16% on the FPT technique side at 2 weeks, 1, 3, and 6 months posttreatment, respectively. The incidence of PIH was significantly lower on the FPT technique side compared to the CT side throughout the follow-up periods. Additionally, transient and mild hypopigmentation occurred in one participant (4%) on the FPT technique side and in five participants (20%) on the CT side. No other adverse effects were observed during the study. The 532-nm picosecond laser emerges as a safe and efficacious treatment modality for SL in individuals with FST III-V. Particularly noteworthy is the efficacy of the FPT technique, which demonstrates comparable effectiveness while significantly reducing the incidence of PIH compared to the CT.

Novel High-Powered 532-nm Picosecond Laser for Solar Lentigines in Fitzpatrick Skin Types III and IV.

Novel High-Powered 532-nm Picosecond Laser for Solar Lentigines in Fitzpatrick Skin Types III and IV.

Comparison of the fractionated Nd: YAG 1064-nm picosecond laser with holographic optics and the fractional CO2 laser in atrophic acne scar treatment: a prospective, randomized, split-face study.

The 1064-nm picosecond laser with holographic optics demonstrated significant efficacy in treating atrophic acne scars. Picosecond lasers with fractionated optics have enabled the development ofa breakthrough skin rejuvenation method. The authors compared the fractionated, non-ablative neodymium-doped yttrium aluminum garnet 1064-nm picosecond laser with holographic optics and the fractional CO2 laser in treating atrophic acne scars. One side of each patient's face was randomly allocated and treated with three sessions of the 1064-nm picosecond laser with holographic optics at 2-month intervals. In contrast, the other side was treated with the fractional CO2 laser. Participants were followed up 3 months after the final session. The primary outcome included the physicians' evaluation using the ECCA grading scale and a four-point scale to assess improvement. The patients' assessment of progress, their overall satisfaction and preferences, and the side effects were also evaluated. No significant difference was observed between the two lasers in terms of the mean ECCA scores after treatments (P = 0.209). The physicians' improvement assessment was more significant for the fractional CO2 laser (P = 0.001). The patients' evaluation of improvement and subjective satisfaction were consistent with physicians' four-point scale results. The picosecond laser side had fewer adverse effects (P < 0.001). The fractionated, non-ablative Nd: YAG 1064-nm picosecond laser with holographic optics and the fractional CO2 laser were effective and safe in treating atrophic acne scars. Significantly better clinical outcomes were observed with the fractional CO2 laser, whereas fewer adverse effects were noted with the 1064-nm picosecond laser with holographic optics.

Combining large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers for promoting protective melanosome autophagy via the PI3K/Akt/mTOR signalling pathway for the treatment of melasma.

Melasma is a common condition of hyperpigmented facial skin. Picosecond lasers are reported to be effective for the treatment of melasma. We aimed to identify the most effective therapeutic mode and elucidate the potential molecular mechanisms of picosecond lasers for the treatment of melasma. Female Kunming mice with melasma-like conditions were treated using four different picosecond laser modes. Concurrently, invitro experiments were conducted to assess changes in melanin and autophagy in mouse melanoma B16-F10 cells treated with these laser modes. Changes in melanin in mouse skin were detected via Fontana-Masson staining, and melanin particles were evaluated in B16-F10 cells. Real-time polymerase chain reaction and western blotting were used to analyse the expression levels of melanosome and autophagy-related messenger ribonucleic acid (mRNA) and proteins. A combination of large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers resulted insignificant decreases in melanin as well as in mRNA and protein expression of melanin-synthesizing enzymes (TYR, TRP-1 and MITF). This combination also led to increased expression of the autophagy-related proteins, Beclin1 and ATG5, with a marked decrease in p62 expression. Intervention with the PI3K activator, 740 Y-P, increased TYR, TRP-1, MITF, p-PI3K, p-AKT, p-mTOR and p62 expression but decreased the expression of LC3, ATG5 and Beclin1. A combination of large-spot low-fluence 1064-nm and fractional 1064-nm picosecond lasers proved more effective and safer. It inhibits melanin production, downregulates the PI3K/AKT/mTOR pathway, enhances melanocyte autophagy and accelerates melanin metabolism, thereby reducing melanin content.

Wavelength-dependent threshold fluences for melanosome disruption to evaluate the treatment of pigmented lesions with 532-, 730-, 755-, 785-, and 1064-nm picosecond lasers.

A threshold fluence for melanosome disruption has the potential to provide a robust numerical indicator for establishing clinical endpoints for pigmented lesion treatment using a picosecond laser. Although the thresholds for a 755-nm picosecond laser were previously reported, the wavelength dependence has not been investigated. In this study, wavelength-dependent threshold fluences for melanosome disruption were determined. Using a mathematical model based on the thresholds, irradiation parameters for 532-, 730-, 755-, 785-, and 1064-nm picosecond laser treatments were evaluated quantitatively. A suspension of melanosomes extracted from porcine eyes was irradiated using picosecond lasers with varying fluence. The mean particle size of the irradiated melanosomes was measured by dynamic light scattering, and their disruption was observed by scanning electron microscopy to determine the disruption thresholds. A mathematical model was developed, combined with the threshold obtained and Monte Carlo light transport to calculate irradiation parameters required to disrupt melanosomes within the skin tissue. The threshold fluences were determined to be 0.95, 2.25, 2.75, and 6.50 J/cm² for 532-, 730-, 785-, and 1064-nm picosecond lasers, respectively. The numerical results quantitatively revealed the relationship between irradiation wavelength, incident fluence, and spot size required to disrupt melanosomes distributed at different depths in the skin tissue. The calculated irradiation parameters were consistent with clinical parameters that showed high efficacy with a low incidence of complications. The wavelength-dependent thresholds for melanosome disruption were determined. The results of the evaluation of irradiation parameters from the threshold-based analysis provided numerical indicators for setting the clinical endpoints for 532-, 730-, 755-, 785-, and 1064-nm picosecond lasers.

Comparison of the 1064-nm picosecond laser with fractionated microlens array and 1565-nm non-ablative fractional laser for the treatment of enlarged pores: a randomized, split-face, controlled trial.

This split-face randomized study compared the efficacy and safety between 1064-nm picosecond laser with fractionated microlens array (MLA) and 1565-nm nonablative fractional laser to treat enlarged pores. Participants with enlarged facial pores were enrolled and underwent three consecutive sessions at 2-week intervals with either a 1064-nm picosecond laser with MLA or a 1565-nm nonablative fractional laser. Images were captured at each visit. Objective (pore number) and subjective assessments, including patient self-evaluations and quartile improvement scales, were used to evaluate the treatment efficacy. The pain levels and adverse effects were recorded at each subsequent visit. The participants were 3 men and 22 women with enlarged facial pores. At the initial and 2-month checkups after the last treatment, the pore numbers were significantly decreased bilaterally for both lasers. The respective quartile improvement scale scores for the 1064-nm picosecond and 1565-nm fractional lasers were 2.22 ± 1.06 and 2.14 ± 1.11, while those for patient self-assessment were 3.72 ± 0.74 and 3.68 ± 0.75. The pore number, quartile improvement scale score, and patients' self-assessments did not differ significantly between the two lasers. Treatment with the 1064-nm picosecond laser better reduced pain compared with the 1565-nm nonablative fractional laser (4.11 ± 1.33 vs. 4.83 ± 1.17). The occurrence of pigmentation did not differ significantly between the lasers. Both the 1064-nm picosecond laser with MLA and the 1565-nm nonablative fractional laser are viable options for treating enlarged pores, and showed comparable respective efficacies; however, the former was less likely to cause hyperpigmentation and was better tolerated.

Evaluation of the efficacy and safety of a 1064nm picosecond Nd:YAG laser for the treatment of atrophic acne scars in Asians

Objective: To evaluate the efficacy and safety of a 1064nm picosecond Nd:YAG laser for atrophic acne scars in Asians. Subject and method: Twenty-three patients with atrophic acne scar lesions were included in this study. Patients were treated with a 1064nm picosecond Nd:YAG laser every 4 weeks for three sessions. The treatment results were evaluated after 1 month of the third session. Result: All patients had a definite reduction in acne scar amount after each session that was maintained during follow-up. Rolling scars and ice-pick responded better (26.7%; 30.8%) to laser treatment than boxcar (15.9%). The Goodman and Baron scores fell from 18.3 ± 7.4 to 13.5 ± 6.8 (a 26.2% improvement), and the change was significant p = 0.001. Conclusion: The 1064nm picosecond Nd:YAG laser is safe and effective for the treatment of acne scars in Asians.

42903 Treatment of hyperpigmentation in photodamaged facial skin using phloretin, vitamin C and ferulic acid serum after a 1064-nm picosecond laser in Latin skin

42903 Treatment of hyperpigmentation in photodamaged facial skin using phloretin, vitamin C and ferulic acid serum after a 1064-nm picosecond laser in Latin skin

Efficacy and Safety of Picosecond Laser in the Treatment of Melasma: A Network Meta-analysis.

The role of lasers in the treatment of melasma and acquired hyperpigmentation disease of the skin has been suggested by clinicians. However, there is no consensus on the most efficient and safe treatment method. To systematically evaluate the efficacy and safety of picosecond laser in the treatment of melasma. PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, Chinese scientific journal database, and Wanfang database were searched. The data for therapeutic efficacy, melasma area and severity score, and incidence rate of adverse reactions were extracted from the included studies. A total of 20 studies involving 1,182 patients were included in this network meta-analysis. Combined therapy with carbamic acid and 1064-nm picosecond laser was the best measure. Melasma area and severity index score of patients after low-power fractional CO2 laser treatment was higher than that of patients after the treatment with 1064-nm picosecond laser. Aminomethyl cyclic acid combined with 1064-nm picosecond laser may have the highest effective rate after treatment. Low-power fractional CO2 laser provided the lowest melasma area and severity index score after treatment, and the incidence rate of adverse reactions after treatment, was highest when intense pulsed light was used.

Early acne scar intervention with 1064nm picosecond laser in patients receiving oral isotretinoin: a randomized split-face controlled pilot study.

Early acne scar intervention is important. Oral isotretinoin is widely used in patients with moderate to severe acne. Picosecond laser has shown a promising effect on scar clearance. However, there is a lack of reports on the efficacy and safety of early acne scar management by using 1064-nm picosecond laser in patients receiving low-dose oral isotretinoin. Twenty-four patients with atrophic acne scars of Fitzpatrick skin type III to V were enrolled. All patients were receiving low-dose oral isotretinoin (0.12-0.22mg/kg/day) during the treatment. The face of the participants was randomly assigned to receive 2 sessions of fractional picosecond 1064nm Nd: YAG laser (FxPico) treatment and 2 follow-ups, with an interval of 1month (month 0-3). Clinical efficacy and safety were assessed by photographs, ECCA grading scale, the number of scar lesions melanin and erythema indexes (MI and EI), TEWL, DLQI, and patient satisfaction and the adverse events were recorded on every visit. FxPico significantly decreased the ECCA score and showed higher improvement in the ECCA score. FxPico treated side achieved a significant reduction in all acne scar types, while only boxcar scars and rolling scars showed higher improvement. TEWL but not MI or EI were significantly improved. DLQI and patient satisfaction were higher with the FxPico-treated side than control side. No adverse effects were observed and all the side effects observed were temporary and tolerable. Early intervention by FxPico on patients receiving low-dose oral isotretinoin is a safe and effective modality to improve atrophic acne scars.

Evaluation of the safety and efficacy of a fractional picosecond 1064nm laser for post-acne erythema in adult Chinese patients.

To evaluate the efficacy and safety of fractional 1064nm picosecond Nd:YAG laser (FPNYL) in the treatment of post-acne erythema (PAE) of adult Chinese. A total of 22 patients received 1 session of treatment and were followed up at the eighth week. Primary outcomes were measured by the Clinician erythema assessment scale (CEAS). Secondary outcomes included a global aesthetic improvement scale (GAIS) and patients' assessment of satisfaction on a five-point scale. Pain scores and adverse effects were also evaluated. Twenty-two patients with Fitzpatrick skin types III and IV were enrolled in the study and completed all treatments and follow-up visits. The mean CEAS scores fell from 2.74±0.80 to 1.95±0.75 (p<0.05). The mean GAIS of PAE improvement was 2.46±0.68. Erythema percentile scores by VISIA increased from 32.63±7.0 to 45.75±11.45 (t=5.442, p=0). The patient satisfaction score was 1.86±1.17. The pain scores were 3.27±1.17 for the FPNYL treatment (varied from 2 to 6). There were moderate erythema and oedema, which last for 3.84±0.78 days. There were overall 68.18% (15/22) patients who felt pruritus in different degrees and 27.27% patients who encountered acne eruptions (white head type). No scar, hyperpigmentation or hypopigmentation was found. Treatment with fractional 1064nm picosecond Nd:YAG laser is effective and safe for PAE of Chinese patients.

Prospective Study of 532-nm Picosecond Laser for the Treatment of Pigmented Lesions of the Face and Dorsal Hands.

Pigmented lesions from chronic UV photoaging are extremely common on the face and hands. To evaluate the safety and efficacy of a 532-nm picosecond laser for these types of pigmented lesions. This was a single-center, prospective, open-label clinical trial. Eligible subjects with pigmentation on the face and hands received 3 monthly treatments, with 1 month (1M) and 3 months (3M) follow-up. Change in investigator-graded overall facial and per lesion pigmentation and subject-graded satisfaction and pigmentation improvement was evaluated by a 5-point scale. Immediate skin response and adverse events (AEs) were evaluated post-treatment. The melanin index was measured using a mexameter. Randomized before and after photographs were graded by 3 blinded physicians for degree of pigmentation improvement. Twenty-five subjects (22F/3M) with Fitzpatrick skin types I-III were enrolled, with 23 subjects completing. Treatments used a 532 nm wavelength, 800 ps pulse duration, 4-6mm spot size, and 0.1 to 0.6J/cm2 fluence. Good-to-excellent clearance at 1M/3M was demonstrated in ≥95% of lesions (n = 116). Only mild treatment-related pain was reported, with transient post-treatment AEs (mean downtime of 2.1 ± 2.0 days) and no serious treatment-related AEs. Subject satisfaction (satisfied or very satisfied) was 95% at 1M and 91% at 3M. Treatment with a 532-nm picosecond laser is safe and highly effective for the treatment of the pigmented lesions of the face and dorsal hands.

Use of combined picosecond 1064nm and thulium laser 1927nm in melasma treatment – case report

Melasma is an acquired, chronic skin pigmentation disorder that affects mainly women and can significantly affect the quality of life and self-esteem of patients. Many therapeutic procedures have been described in the literature, nevertheless the disease is difficult to treat.&#x0D; A case report. The paper presents a case of successful laser treatment in a 44-year-old woman with a long history of facial skin discoloration of the type of melasma. The patient was treated with combined laser therapy in the area of ​​facial discoloration with a picosecond laser and a thulium laser.&#x0D; Aim The aim of this study is to draw attention to the possibility of using laser therapy in the treatment of melasma-type skin hyperpigmentation. In this article, we describe a case of brightening of a melasma-type discoloration during a single laser treatment combining the use of a 1064nm picosecond laser and a 1927nm thulium laser, in order to meet interests of patients and physicians in the use of laserotherapy in the treatment of discoloration, especially in patients who do not tolerate well the side effects of pharmacological therapies.&#x0D; Conclusions. The use of laser therapy, with particular emphasis on the picosecond and thulium laser, can be an important and effective element in the treatment of melasma-type hyperpigmentation of the skin.

Outcomes of 1064-nm picosecond laser alone and in combination with fractional 1064-nm picosecond laser in tattoo removal.

Removal of the unwanted tattoo was initially focused treatment of picosecond laser in the setting of the unfractionated beam, whereas the fractionated 1064-nm picosecond lasers (Fr-Pico) has been successfully utilized in various skin conditions, including scar and benign pigmented lesions. However, no studies compared the combination of Fr-Pico and unfractional 1064-nm picosecond laser (UFr-Pico) and UFr-Pico alone in tattoo removal. This study aims to compare the efficacy and safety of the combination of Fr-Pico and UFr-Pico and the UFr-Pico and in tattoo removal. Nineteen black tattoos in 11 patients were treated with UFr-Pico on one half and in combination with Fr-Pico on another half over three sessions with 4-week intervals and 4-week follow-up after the last session. Treatment efficacy was assessed using digital photographs, skin imaging analysis, and patient satisfaction. After three treatments, tattoo clearance scores revealed that greater than 50% clearance was achieved in 11 (84.6%) tattoos treated with combination side and 9 (69.2%) tattoos with UFr-Pico alone. Significant differences were observed between the groups at 8 and 12weeks. Skin textural changes also demonstrated significant improvements in the combination side at Week 12. Adverse events, such as blistering and textural changes, were fewer in the combination side. The combination of 1064nm Fr-Pico and UFr-Pico may be more effective and safer in tattoo removal than UFr-Pico alone.

Randomized, evaluator-blinded comparative study of a potassium titanyl phosphate (KTP) 532-nm picosecond laser and an alexandrite 755-nm picosecond laser for the treatment of solar lentigines in Asians.

Various pigment-specific lasers can be used to treat solar lentigines. However, the most effective treatment options remain to be explored to reduce complications, such as postinflammatory hyperpigmentation, especially in dark-skinned patients. This study aims to compare the efficacy and safety between the KTP 532-nm picosecond laser and the alexandrite 755-nm picosecond laser for the treatment of solar lentigines in Asians. Thirty patients who had at least two solar lentigines on their arms were enrolled. A total of 30 paired lentiginous lesions were randomly selected for a single treatment with either a KTP 532-nm picosecond laser or an alexandrite 755-nm picosecond laser. Mean luminance score (L*) was evaluated at baseline and at 6 and 12weeks to determine treatment efficacy. Improvement was assessed by a blinded physician using a 5-point score. Satisfaction was rated by patients using a visual analog scale. All adverse events were documented. All 30 patients completed the study. Both lasers showed significant improvement in mean L* from baseline (p<0.001). With the parameter settings employed, lesions treated with the alexandrite 755-nm picosecond laser showed greater improvement in mean L* when compared with treatment with the KTP 532-nm picosecond laser at 12weeks follow-up (p=0.002). According to physician scoring, more than 50% improvement was observed in 25 and 19 lesions of the alexandrite 755-nm picosecond laser group and the KTP 532-nm picosecond laser group, respectively. Adverse events did not differ between groups. A significantly higher satisfaction score was observed with the alexandrite 755-nm picosecond laser at the last visit (p=0.038). Both types of picosecond laser may be used to treat solar lentigines. Proper treatment settings and endpoint observation are the most important factor to achieve a successful outcome.

The dual toning technique of 1064nm Nd:YAG picosecond and quasi-long pulsed laser combined with D-pigment cream in treatment of melasma

Objective: To evaluate the efficacy and safety of the dual toning laser of Nd:YAG 1064nm picosecond and quasi-long pulsed laser combined with D-pigment night cream in treatment of severe melasma. Subject and method: Twenty four Vietnamese females, mean age of 44.46 ± 8.04 years, Fitzpatrick skin type IV with the clinical diagnosis of dermal and mixed-type melasma were treated with 5 combination sessions of picosecond laser Nd:YAG 1064nm (Picoplus) with a spot size of 8mm, the energy of 0.65 - 0.8J/cm2 and quasi-long pulsed mode laser (Clarity) with the duration of 0.35ms, the spot size of 15mm, the energy of 2.6J/cm2, ICD (Intelligent Cool Device) off. Mild and transient erythema was the endpoint. Laser treatments were given every 4 weeks. All patients were applied with UVA/B sunscreen, SPF of at least 30 in daytime and D-pigment cream at night. Improvement was rated by mMASI at the baseline (first -T1) and after 5 sessions (sixth -T6). Result: The mean mMASI score of 24 patients at T1 was 11.10 ± 3.59 (min 6.0; max 22.4); after one month of 5th session, the mean mMASI score at T6 was reduced to 5.43 ± 2.18 (min 1.8 - max 11.0) (mMASI score reduced by a mean of 5.68 ± 2.36), achieving 51.06 ± 13.17% reduction. There were no unexpected side effects in any patients. Conclusion: Dual toning technique using 1064nm Nd:YAG picosecond and quasi-long pulsed laser combined with D-pigment cream at night was safe, effective and well-tolerated in treatment of patients with melasma. Further larger studies should be carried out with control to confirm the advantage of the method.

Two-photon fluorescence lifetime for label-free microfluidic droplet sorting

Microfluidic droplet sorting systems facilitate automated selective micromanipulation of compartmentalized micro- and nano-entities in a fluidic stream. Current state-of-the-art droplet sorting systems mainly rely on fluorescence detection in the visible range with the drawback that pre-labeling steps are required. This limits the application range significantly, and there is a high demand for alternative, label-free methods. Therefore, we introduce time-resolved two-photon excitation (TPE) fluorescence detection with excitation at 532 nm as a detection technique in droplet microfluidics. This enables label-free in-droplet detection of small aromatic compounds that only absorb in a deep-UV spectral region. Applying time-correlated single-photon counting, compounds with similar emission spectra can be distinguished due to their fluorescence lifetimes. This information is then used to trigger downstream dielectrophoretic droplet sorting. In this proof-of-concept study, we developed a polydimethylsiloxane-fused silica (FS) hybrid chip that simultaneously provides a very high optical transparency in the deep-UV range and suitable surface properties for droplet microfluidics. The herein developed system incorporating a 532-nm picosecond laser, time-correlated single-photon counting (TCSPC), and a chip-integrated dielectrophoretic pulsed actuator was exemplarily applied to sort droplets containing serotonin or propranolol. Furthermore, yeast cells were screened using the presented platform to show its applicability to study cells based on their protein autofluorescence via TPE fluorescence lifetime at 532 nm.Graphical abstract