Visible light. Part I: Properties and cutaneous effects of visible light

Photobiomodulation of Blue Light Enhance Melanoma Cellular Recovery Following Viral Infection via Mitochondrial Pathways

This study aimed to elucidate the response of B16F10 cells to blue light following infection with an empty adenoviral vector (Adv). Twenty-four hours post-infection, the B16F10 cells underwent phototherapy, and a range of cellular parameters were assessed, including cell viability, melanin content, cell cycle progression, reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), apoptosis, necrosis, lactate dehydrogenase (LDH) release, and autophagy. The findings indicated that Adv infection elevated melanin content and autophagy, resulting in G1 phase cell cycle arrest. In comparison to the control group, light-treated, Adv-infected cells exhibited reduced inhibition rates, LDH release, apoptosis, and necrosis, while MMP and ROS levels were elevated. The study concluded that although Adv, as a gene delivery vector in conjunction with light therapy, significantly modulated melanin content and autophagy. Moreover, while melanin's light absorption capacity mitigated MMP reduction, the resultant excitation molecules generated ROS, enhancing oxidative stress.

Visible Blue Light Does Not Induce DNA Damage in Human Dermal Fibroblasts

Photobiomodulation (PBM) is a noninvasive treatment modality that utilizes light to influence cellular activity. PBM has applications in various dermatological conditions. As blue light (BL, 400-500 nm) therapy gains popularity, concerns about its potential to induce DNA damage remain. This study investigates the effects of fluorescent BL (417 ± 5 nm) on human dermal fibroblast DNA, specifically examining the formation of cyclobutane pyrimidine dimers (CPD) and 6-4 photoproducts (6-4PPs) at fluences of 10, 30, and 45 J/cm2. Our results demonstrate that BL exposure does not induce detectable DNA damage, in contrast to the well-documented effects of ultraviolet light, which is known to cause such damage. These findings support the safety of fluorescent BL therapy and align with prior research on LED-red and LED-near-infrared wavelengths. Continued clinical investigation of the effects of BL on skin will add to the understanding of the safety profile.

Sunscreens part 1: Mechanisms and efficacy

As our knowledge of the harmful effects of ultraviolet radiation continues to evolve, sunscreen remains an integral part of a comprehensive photoprotection strategy against multiple endpoints of ultraviolet radiation-mediated damage. Part 1 of this review covers sunscreen active and additive ingredient properties, mechanisms of action and gaps in coverage. Following an overview of sunscreen's efficacy in protecting against sunburn, photocarcinogenesis, photoaging, pigmentary disorders, and idiopathic photodermatoses, we highlight considerations for product use and selection in children and individuals with skin of color.

The Pigmentation of Blue Light Is Mediated by Both Melanogenesis Activation and Autophagy Inhibition through OPN3-TRPV1

Blue light, a high-energy radiation in the visible light spectrum, was recently reported to induce skin pigmentation. In this study, we investigated the involvement of TRPV1-mediated signaling along with OPN3 in blue light-induced melanogenesis as well as its signaling pathway. Operating downstream target of OPN3 in blue light-induced melanogenesis, blue light activated TRPV1 and upregulated its expression, resulting in calcium influx. Calcium ion induced the activation of calcium/calmodulin-dependent protein kinase II and MAPK. It also downregulated clusterin expression, leading to the nuclear translocation of PAX3, ultimately affecting melanin synthesis. In addition, blue light interfered with autophagy-mediated regulation of melanosomes by decreasing not only the interaction between clusterin and LC3B but the expression of activating transcription factor family. These findings demonstrate that the pigmenting effects of blue light are mediated by calcium/calmodulin-dependent protein kinase II- and MAPK-mediated signaling as well as clusterin-dependent inhibition of autophagy through OPN3-TRPV1-calcium influx, suggesting, to our knowledge, a previously unreported signaling pathway through which blue light regulates melanocyte biology. Furthermore, these results suggest that TRPV1 and clusterin could be potential therapeutic targets for blue light-induced pigmentation due to prolonged exposure to blue light.

UV/blue-light-blocking polylactide films derived from bio-sources for food packaging application

Transparent biodegradable packaging materials capable of blocking the broad-spectrum of UV and blue light (200-500 nm) are crucial for packaging of light-sensitive food. This study offers a fully bio-based solution based on polylactide and natural light absorbers, aloe-emodin (AE) and riboflavin (RF), whose combined UV-vis absorption spectrum covers all the light between 200 and 500 nm. AE and RF were bonded to polylactide chains by serving as initiators for the ring-opening polymerization of lactide, resulting in the synthesis of light-blocking polylactides, PLA-E and PLA-R. To fabricate UV and blue light-blocking polylactide film (PLA/EmRn), PLA-E and PLA-R were blended with commercial polylactide. For the PLA/EmRn film containing only 0.87 mass% AE and RF group introduced by PLA-E and PLA-R, the transmittance against the UV-B, UV-A and blue light was only 38.8 %, 27.7 % and 25.5 %, respectively. Meanwhile, the film maintains high transparency (91.4 %) and good tensile strength above 59 MPa. Furthermore, the PLA/EmRn film exhibits an extended capacity for light-blocking, which may help reduce the photodegradation of the photosensitive nutrient riboflavin. Its protective performance surpasses both the polylactide film and commercially available PET packaging films. This study offers an eco-friendly strategy for developing UV/blue light-blocking food packaging based on all renewable resources.

Blue Light Emitting Diode Suppresses Sarcoma Cell Proliferation via the Endogenous Apoptotic Pathway Without Damaging Normal Cells

BACKGROUND

The development of novel therapies for sarcoma is urgently required because most sarcomas are refractory to adjuvant therapy and the treatment options are limited. Although antitumor effects of blue light (BL) have been reported for several malignant tumors, its impact on various sarcomas remains unknown. In this study, we examined the antitumor effects of BL on several kinds of bone and soft tissue sarcomas.

METHODS

We used human osteosarcoma, undifferentiated pleomorphic sarcoma, liposarcoma, and myxofibrosarcoma cell lines, as well as a human dermal fibroblast cell line as normal cells. We continuously irradiated these cells with BL in an incubator.

RESULTS

BL inhibited cell proliferation in sarcoma cells, but hardly affected normal cells. BL increased intracellular reactive oxygen species (ROS) levels in sarcoma cells, but not in normal cells. Interestingly, oxidative stress occurred after BL irradiation in both sarcoma and normal cells. In addition, apoptosis, autophagy, and mitochondrial dysfunction, which were induced by ROS, occurred in sarcoma cells. In undifferentiated pleomorphic sarcoma cells, BL caused cell death through activation of the endogenous apoptotic pathway, and autophagy counteracted the apoptosis.

CONCLUSION

Our results indicate that BL might specifically kill sarcoma cells without injuring normal cells and may become a new treatment option for sarcoma.

Moderate static magnetic field modulated lipid metabolism abnormalities induced by continuous artificial light in Caenorhabditis elegans: Role of iron ions

Excessive use of artificial light sources has led to a significant increase in light pollution, which has raised serious concerns due to its serious adverse effects on lipid metabolism. Although moderate static magnetic fields (SMFs) have shown potential in health intervention and treatment as non-invasive and highly permeable physical field, the influence of SMFs on lipid metabolic disturbance induced by lights remains largely unknown. In this study, we explored the lipid metabolism of Caenorhabditis elegans (C. elegans) under varying wavelengths of light ranging from 395 nm to 635 nm, both in the presence and absence of a 0.5 T SMF, and elucidated their underlying mechanisms. Exposure of C. elegans to artificial light at 200 lux resulted in a shortened lifespan while significantly increasing fat accumulation in a wavelength-dependent manner. The presence of 0.5 T SMF significantly extended the lifespan and reduced the size of fat droplets, as well as the content of triglyceride in light exposed worms. These effects were achieved by upregulating the expression of genes related to lipolysis and downregulating the expression of genes related to lipid synthesis. Moreover, the 0.5 T SMF alleviated abnormalities in lipid metabolism caused by light through the regulation of iron ions. Our findings provided clear evidence that moderate SMFs have significant protective effects on lipid metabolism abnormalities induced by artificial light via mediating iron homeostasis, which might contribute to a better understanding of the combined photomagnetic effects in living organisms.

Here Comes the Sun! A Study on Sun Exposure and Associated Risks in the Canadian Population

OBJECTIVE

To evaluate the awareness of and attitudes toward various aspects of sun-exposure risks and protection methods among Canadians.

METHODS

An online survey conducted from September 28 to October 18, 2021, included 17,001 participants aged 18 years and above from 17 countries across 5 continents; the data presented are those of the Canadian population (n = 1,000). The survey focused on demographics, sun-exposure habits, comprehension of risks, and knowledge of photoprotection. The results were analyzed using descriptive statistics to identify prevalent trends and discrepancies in sun-protective behaviours among Canadians.

RESULTS

The majority of Canadian respondents (93%) acknowledged the health risks associated with sun exposure. While 81% of Canadians reported using some form of sun protection, only 10% systematically implemented all recommended protective measures, highlighting a gap in knowledge translation. Misconceptions regarding the safety of tanned skin and the effectiveness of sunscreens were widespread, particularly in younger demographics and in individuals with darker skin. Knowledge and preventive behaviours were markedly better among individuals who regularly consult dermatologists.

CONCLUSIONS

This study highlights general awareness of sun-protective behaviours but a lack of universal and comprehensive implementation among Canadians. Given the knowledge gaps in younger demographics and darker skin phototypes, targeted educational initiatives are essential to correct prevalent misconceptions about sun exposure and tanned skin. Dermatologists and other health care professionals can play a pivotal role in education and primary prevention strategies for skin cancer and other sun-related comorbidities.

Photobiomodulation (100 mW) caution applied to tattooed skin: a cross-sectional study

Photobiomodulation is a technique that can modulate cellular processes and promote therapeutic effects, with the vast majority of applications being painless and nonperceptible. This study aims to determine whether tattooed skin influences cutaneous sensory perception during photobiomodulation application. A cross-sectional study. Participants: 30 participants with tattooed skin on some body regions, mainly on the upper limbs. Data collection was performed in a controlled laboratory environment by a previously trained evaluator. Four modes of irradiation were applied to the skin of the participants, and their sensory perceptions were analyzed with the average time and energy for participants to manifest during irradiations of the PBM. The interventions showed statistically significant differences when comparing the different application mode groups in terms of intervention time with the placebo model. There was an average time and energy during the irradiations: cluster 12s (1.2 J), 660 nm 21s (2.1 J) and 808 nm 14s (1.4 J) until the participants manifested. As a limitation of the study, we can describe the non-observation of skin types I and VI according to the Fitzpatrick scale. This study was evident that tattoos may affect cutaneous sensory perception during photobiomodulation irradiation in all application modes, and the first manifestations reported were: warmth, tingling, and heating.

Australian Sunscreens: The Price of Protection for Skin of Colour With Pigmentary Disorders

Australia experiences some of the highest ultraviolet radiation (UVR) levels globally, known for causing sunburn, skin cancers, photoageing and immunosuppression. While effects of UVA and UVB are well-studied, visible light (VL; 400-700 nm) is the driving force behind pigmentary disorders, especially in skin of colour (SOC) patients. Nearly 50% of Australians are affected, with significant impacts on appearance and psychological well-being. Tinted sunscreens containing iron oxides and pigmentary-grade titanium dioxide are the only effective options for blocking VL. However, Australia's stringent Therapeutic Goods Administration (TGA) regulations limit the availability of colour-matched tinted sunscreens, significantly impacting SOC patients. SOC patients may also underestimate their need for photoprotection, believing their skin provides sufficient natural protection. In dermatological practice, tailored sunscreen recommendations for darker skin tones may sometimes be overlooked. This review explores the barriers to effective treatment and the cost implications for SOC individuals suffering from pigmentary disorders in Australia. The goal is to guide both patients and dermatologists in making informed decisions on VL protection and skin tone matching.

Challenging the skin pigmentation bias in tissue oximetry via time-domain near-infrared spectroscopy

Recently, skin pigmentation has been shown to affect the performance of pulse oximeters and other light-based techniques like photo-acoustic imaging, tissue oximetry, and continuous wave near-infrared spectroscopy. Evaluating the robustness to changes in skin pigmentation is therefore essential for the proper use of optical technologies in the clinical scenario. We conducted systematic time-domain near-infrared spectroscopy measurements on calibrated tissue phantoms and in vivo on volunteers during static and dynamic (i.e., arterial occlusion) measurements. To simulate varying melanosome volume fractions in the skin, we inserted, between the target sample and the measurement probe, thin tissue phantoms made of silicone and nigrosine (skin phantoms). Additionally, we conducted an extensive measurement campaign on a large cohort of pediatric subjects, covering the full spectrum of skin pigmentation. Our findings consistently demonstrate that skin pigmentation has a negligible effect on time-domain near-infrared spectroscopy results, underscoring the reliability and potential of this emerging technology in diverse clinical settings.

Synthesis of eco-friendly CaCO3@Zn-Al MMO core-shell nanoflowers photocatalyst using bio-eggshell waste for improved photocatalytic degradation of RhB under visible light irradiation

In this study, a type-I heterojunction was synthesized based on eggshell waste doped mixed metal oxide (ES@ZnAl MMO) for the degradation of RhB dye under visible light irradiation. The ES@ZnAl MMO core-shell was synthesized using waste eggshell and layered double hydroxide (LDH) as primary precursors. After their mechanochemical assembly and thermal treatment, CaCO3 was formed in both calcite and vaterite forms, alongside mixed metal oxides derived from the LDH (ZnO and Al2O3). The formation of a heterojunction between the semiconductors results in an improved activation of sites, a decrease in bandgap energy from 5.72 to 3.44 eV, and an increase in degradation capacity. The elemental composition, morphology, structural, and optical properties of the ES@ZnAl MMO nanocomposite were analyzed using various techniques. The optimal ES@ZnAl MMO photocatalyst demonstrated superior performance, reaching over 98% of RhB dye degradation under optimal conditions, outperforming pure ZnAl LDH, ZnAl MMO, and ES. After five run cycles, the ES@ZnAl MMO heterojunction still maintained a high photocatalytic performance for RhB dye (99%). Furthermore, it displayed high performance in degrading various other pollutants, including OG, IC, MB, and 2.4-DP, with degradation efficiencies of 97%, 99%, 99%, and 87%, respectively. This economically advantageous heterojunction showed its importance in environmental remediation, presenting a promising solution for addressing diverse pollution challenges.

Advances in the Application of Infrared in Food Processing for Improved Food Quality and Microbial Inactivation

Food processing is a fundamental requirement for extending the shelf life of food products, but it often involves heat treatment, which can compromise organoleptic quality while improving food safety. Infrared (IR) radiation has emerged as a transformative technology in food processing, offering a rapid, energy-efficient method for inactivating microbial cells and spores while preserving the nutritional and sensory attributes of food. Unlike traditional heating methods, IR technology enhances heating homogeneity, shortens processing time, and reduces energy consumption, making it an environmentally friendly alternative. Additionally, IR processing minimizes water usage, prevents undesirable solute migration, and maintains product quality, as evidenced by its effectiveness in applications ranging from drying fruits and vegetables to decontaminating meat and grains. The advantages of IR heating, including its precise and even heat diffusion, ability to retain color and nutrient content, and capacity to improve the microbial safety of food, position it as a promising tool in modern food preservation. Nevertheless, there are gaps in knowledge with respect to optimal application of IR in foods, especially in the maintenance product quality and the impact of factors such as IR power level, temperature, wavelength (λ), food depth, and target microorganisms on the applicability of this novel technology in food systems. Recent research has attempted to address challenges to the application of IR in food processing such as its limited penetration depth and the potential for surface burns due to high energy which has delayed the widespread utilization of this technology in food processing. Thus, this review critically evaluates the application of IR in food safety and quality, focusing on factors that affect its effectiveness and its use to moderate food quality and safety while comparing its advantages/disadvantages over traditional thermal processing methods.

Novel catalyst-free activation of chlorine by visible light for micropollutant abatement

This study systematically investigated the direct activation of chlorine by visible light emitting diode (Vis-LED). Vis-LED could effectively activate chlorine to degrade micropollutants with degradation efficiency and pseudo-first-order degradation rate constant range of 64.3-100 % and 0.0340-0.195 min-1, respectively. Quenching experiments and modeling results suggested that reactive chlorine species (RCS, including ClO•, Cl2•-, and Cl•) and hydroxyl radical (•OH) were involved in the degradation of atenolol (ATL). The contribution ratio of ClO•, free available chlorine, Cl•, Cl2•-, and •OH to ATL degradation were 58.7 %, 17.4 %, 15.6 %, 1.8 %, and 5.9 %, respectively, in Vis-LED448/chlorine process. Moreover, the innate quantum yields of HClO and ClO- decreased from 0.229 and 0.0206 to 0.0489 and 0.0109 mol·Einstein-1, respectively, as the wavelength increased from 448 to 513 nm, leading to a decrease in ATL degradation, which was consistent with the model results. Experimental and modeling results have confirmed that ATL degradation decreased when pH increased from 4.0 to 9.0. Cl- had little effect on the degradation of ATL, while HA and HCO3- affected ATL degradation by scavenging reactive species and/or shielding effect. The concentration of disinfection by-products decreased with the increase of wavelength and pH. In summary, Vis-LED/chlorine is an efficient water treatment process even without a catalyst.

Comparison of the mechanisms of DNA damage following photoexcitation and chemiexcitation

In this review, we compare the mechanisms and consequences of electronic excitation of DNA via photon absorption or photosensitization, as well as by chemically induced generation of excited states. The absorption of UV radiation by DNA is known to produce cyclobutane pyrimidine dimers (CPDs) and thymine pyrimidone photoproducts. Photosensitizers are known to enable such transformations using UV-A and visible light by generating triplet species able to transfer energy to DNA. Conversely, chemiexcitation of DNA is a process related to the formation of high energy peroxides whose decomposition leads to triplet excited species. In practice, both photoexcitation and chemiexcitation produce reactive excited species able to promote some DNA nucleobases to their excited state. We discuss the effect of epigenetic methylation modifications of DNA and the role of endogenous and exogenous photosensitizers on the formation of DNA photoproducts via triplet-triplet energy transfer as well as oxidative DNA damages. The mechanisms of pathogenic pathway involving the generation of CPDs via chemiexcitation (namely dark CPDs, dCPDs) are discussed and compared with photoexcitation considering their spatiotemporal characteristics. Recognition of the multifaceted noxious effects of UV radiation opens new horizons for the development of effective electronically excited quenchers, thereby providing a crucial step toward mitigating DNA photodamage.

Skin Phototype Classification with Machine Learning Based on Broadband Optical Measurements

The Fitzpatrick Skin Phototype Classification (FSPC) scale is widely used to categorize skin types but has limitations such as the underrepresentation of darker skin phototypes, low classification resolution, and subjectivity. These limitations may contribute to dermatological care disparities in patients with darker skin phototypes, including the misdiagnosis of wound healing progression and escalated dermatological disease severity. This study introduces (1) an optical sensor measuring reflected light across 410-940 nm, (2) an unsupervised K-means algorithm for skin phototype classification using broadband optical data, and (3) methods to optimize classification across the Near-ultraviolet-A, Visible, and Near-infrared spectra. The differentiation capability of the algorithm was compared to human assessment based on FSPC in a diverse participant population (n = 30) spanning an even distribution of the full FSPC scale. The FSPC assessment distinguished between light and dark skin phototypes (e.g., FSPC I vs. VI) at 560, 585, and 645 nm but struggled with more similar phototypes (e.g., I vs. II). The K-means algorithm demonstrated stronger differentiation across a broader range of wavelengths, resulting in better classification resolution and supporting its use as a quantifiable and reproducible method for skin type classification. We also demonstrate the optimization of this method for specific bandwidths of interest and their associated clinical implications.

Impact of blue light on cutaneous barrier structures and properties: NPLC/HR-MSn and Raman analyses

Skin health relies heavily on a well-maintained cutaneous barrier. While the detrimental effects of UV radiation on the epidermis are established, the impact of blue light, a significant component of sunlight and artificial sources, is less clear. This study aims to explore blue light's influence on the reconstructed human epidermis (RHE) using two complementary analytical approaches: Raman microspectroscopy and normal phase liquid chromatography coupled with high-resolution mass spectrometry (NPLC/HR-MSn). RHE samples were exposed to blue light (415 nm and 455 nm) during different stages of their maturation. Raman spectra were acquired for both irradiated and non-irradiated (control) samples. Raman descriptors were analyzed to assess potential alterations in the structural organization of proteins and lipids' conformational changes. Additionally, lipids from RHE samples were extracted and analyzed using NPLC/HR-MSn. Blue light exposure led to changes in the structural organization of RHE lipids and proteins, as well as changes in the lipid composition. These changes varied depending on the wavelength and exposure dose. Exposure to blue light could disrupt the integrity of the skin's protective barrier, leading to increased sensitivity to environmental stressors and potential skin damage.

Overcoming Biopotency Barriers: Advanced Oral Delivery Strategies for Enhancing the Efficacy of Bioactive Food Ingredients

Bioactive food ingredients contribute to the promotion and maintenance of human health and wellbeing. However, these functional ingredients often exhibit low biopotency after food processing or gastrointestinal transit. Well-designed oral delivery systems can increase the ability of bioactive food ingredients to resist harsh environments inside and outside the human body, as well as allow for controlled or triggered release of bioactives to specific sites in the gastrointestinal tract or other tissues and organs. This review presents the characteristics of common bioactive food ingredients and then highlights the barriers to their biopotency. It also discusses various oral delivery strategies and carrier types that can be used to overcome these biopotency barriers, with a focus on recent advances in the field. Additionally, the advantages and disadvantages of different delivery strategies are highlighted. Finally, the current challenges facing the development of food-grade oral delivery systems are addressed, and areas where future research can lead to new advances and industrial applications of these systems are proposed.

Photobiomodulation CME part II: Clinical applications in dermatology

Photobiomodulation (PBM) is an emerging treatment modality in dermatology with increasing office and home-based use. PBM is the use of various light sources in the red light (620-700 nm) and near-infrared (700-1440 nm) spectrum as a form of light therapy. PBM is often administered through low-level lasers or light-emitting diodes. Studies show that PBM can be used effectively to treat conditions secondary to cancer therapies, alopecia, ulcers, herpes simplex virus, acne, skin rejuvenation, wounds, and scars. PBM offers patients many benefits compared to other treatments. It is noninvasive, cost-effective, convenient for patients, and offers a favorable safety profile. PBM can be used as an alternative or adjuvant to other treatment modalities including pharmacotherapy. It is important for dermatologists to gain a better clinical understanding of PBM for in-office administration and to counsel patients on proper application for home-use devices to best manage safety and expectations as this technology develops. PBM wavelengths can induce varied biological effects in diverse skin types, races, and ethnicities; therefore, it is also important for dermatologists to properly counsel their skin of color patients who undergo PBM treatments. Future clinical trials are necessary to produce standardized recommendations across conditions and skin types.

Photobiomodulation CME part I: Overview and mechanism of action

Photobiomodulation (PBM), previously known as low-level laser light therapy, represents a noninvasive form of phototherapy that utilizes wavelengths in the red light (RL, 620-700 nm) portion of the visible light (VL, 400-700 nm) spectrum and the near-infrared (NIR, 700-1440 nm) spectrum. PBM is a promising and increasingly used therapy for the treatment of various dermatologic and nondermatologic conditions. Photons from RL and NIR are absorbed by endogenous photoreceptors including mitochondrial cytochrome C oxidase (COX). Activation of COX leads to the following changes: modulation of mitochondrial adenosine triphosphate (ATP), generation of reactive oxygen species (ROS), and alterations in intracellular calcium levels. The associated modulation of ATP, ROS and calcium levels promotes the activation of various signaling pathways (eg, insulin-like growth factors, phosphoinositide 3-kinase pathways), which contribute to downstream effects on cellular proliferation, migration, and differentiation. Effective PBM therapy is dependent on treatment parameters (eg, fluence, treatment duration and output power). PBM is generally well-tolerated and safe with erythema being the most common and self-limiting adverse cutaneous effect.

Human adipose and umbilical cord mesenchymal stem cell-derived extracellular vesicles mitigate photoaging via TIMP1/Notch1

UVB radiation induces oxidative stress, DNA damage, and inflammation, leading to skin wrinkling, compromised barrier function, and an increased risk of carcinogenesis. Addressing or preventing photoaging may offer a promising therapeutic avenue for these conditions. Recent research indicated that mesenchymal stem cells (MSCs) exhibit significant therapeutic potential for various skin diseases. Given that extracellular vesicles (EV) can deliver diverse cargo to recipient cells and elicit similar therapeutic effects, we investigated the roles and underlying mechanisms of both adipose-derived MSC-derived EV (AMSC-EV) and umbilical cord-derived MSC-derived EV (HUMSC-EV) in photoaging. Our findings indicated that in vivo, treatment with AMSC-EV and HUMSC-EV resulted in improvements in wrinkles and skin hydration while also mitigating skin inflammation and thickness alterations in both the epidermis and dermis. Additionally, in vitro studies using human keratinocytes (HaCaTs), human dermal fibroblast cells (HDFs), and T-Skin models revealed that AMSC-EV and HUMSC-EV attenuated senescence, reduced levels of reactive oxygen species (ROS) and DNA damage, and alleviated inflammation induced by UVB. Furthermore, EV treatment enhanced cell viability and migration capacity in the epidermis and promoted extracellular matrix (ECM) remodeling in the dermis in photoaged cell models. Mechanistically, proteomics results showed that TIMP1 was highly expressed in both AMSC-EV and HUMSC-EV and could exert similar effects as MSC-EV. In addition, we found that EV and TIMP1 could inhibit Notch1 and downstream targets Hes1, P16, P21, and P53. Collectively, our data suggests that both AMSC-EV and HUMSC-EV attenuate skin photoaging through TIMP1/Notch1.

Advancements in skin cancer treatment: focus on photodynamic therapy: a review

Some of these include basal cell carcinoma (BCCs), squamous cell carcinoma (SCCs), and melanoma; skin cancer is a leading global health problem due to its high prevalence and possibly due to its serious health implications. Conventional and known therapies like surgeries, radiation therapies and chemotherapy although helpful are sometime deleterious and do not specifically attack the cancers. New advancement is half-breed technique has recently been recognized that photodynamic therapy (PDT) can be considered as a potentially effective modality by using photosensitizers which work through the generation of localized ROS on exposure to light. This review analyzes the recent progress in PDT and evaluation of its effectiveness in the cure of skin malignancies: with the emphasis on its applicability to BCCs and SCCs, as well as the limitations concerning the cure of melanomas. This review gives an insight to how PDT works and how it can be combined with other forms of therapy, and the prospects of photosensitizer carriers with special reference to nanotechnology. Also, the optimization of the parameters associated with the use of PDT is explored in an attempt to improve on its safety and efficacy in treatment. As such, the purpose of this systematic review of the literature is to advance the knowledge of PDT usage in contemporary dermatologic oncology and to contribute to the eventual expansion of this therapy into other skin diseases and potential use as a first-line treatment for skin neoplasia.

Surface properties of carbon nitride materials used in photocatalytic systems for energy and environmental applications

The use of photocatalytic systems involving semiconductor materials for environmental and energy applications, such as water remediation and clean energy production, is highly significant. In line with this, a family of carbon-based polymeric materials known as carbon nitride (CNx) has emerged as a promising candidate for this purpose. Despite CNx's remarkable characteristics of performance, stability, and visible light responsiveness, its chemical inertness and poor surface properties hinder interfacial interactions, which are key to effective catalysis. This highlight reviews the literature focusing on the surface chemistry of CNx, especially its structural formation pathway, reactivity, and solvent interactions. It also explores recent advancements in the use of modified CNx for hydrogen production and arsenic remediation, offering recommendations for future material design improvements.

Visualization, Dynamicity, and Collaborative Networking of Scientific Production on Visible Light and Skin Aging: A Scientometric Analysis

Purpose: The purpose of this is to examine the visualization, dynamicity, and collaborative networking of scientific production on visible light (VL) and skin aging through scientometric analysis. Materials and Methods: This research consisted of a cross-sectional and descriptive design with a scientometric approach that examined the publication trends and collaborative patterns among authors and institutions from 2018 to 2023. A comprehensive search strategy was also employed by using specific keywords related to VL and skin aging. In this case, several indicators were employed, including scholarly output, view count, field-weighted citation impact (FWCI), and citation count. The analyses were performed by using SciVal software and R Studio version 4.3.2. Results: A total of 180 sources were identified, with 280 documents generated, indicating an annual growth rate of 6.72%. The documents, averaging 3.25 years in age, received an average of 12.14 citations, revealing their impact. Additionally, collaborations were evident, with a ratio of 5.6 coauthors per paper and 25.71% consisting of international collaborations. In terms of institutions, there were notable disparities in scholarly activities and impact metrics, highlighting the diversity of the research landscape. Meanwhile, journals, such as Photodermatology, Photoimmunology and Photomedicine, revealed a substantial impact (FWCI 2.05). Overall, the impact of the journals showed a general upward trend, reflecting dynamicity and variability over time. Conclusion: An annual growth rate of 6.72% was found, with 180 sources and 280 papers on VL and skin aging. Moreover, international collaborations, the positive impact in leading journals, and the distribution patterns identified through scientometric laws underscored the vitality and complexity of the field. These results offer valuable insights into guiding future research in this multidisciplinary field.

Uncovering key mechanisms and intervention therapies in aging skin

Advancements in understanding skin aging mechanisms, which encompass both external and internal aging processes, have spurred the development of innovative treatments primarily aimed at improving cosmetic appearance. These findings offer the potential for the development of novel therapeutic strategies aimed at achieving long-term, non-therapy-dependent clinical benefits, including the reversal of aging and the mitigation of associated health conditions. Realizing this goal requires further research to establish the safety and efficacy of targeting aging-related skin changes, such as pigmentation, wrinkling, and collagen loss. Systematic investigation is needed to identify the most effective interventions and determine optimal anti-aging treatment strategies. These reviews highlight the features and possible mechanisms of skin aging, as well as the latest progress and future direction of skin aging research, to provide a theoretical basis for new practical anti-skin aging strategies.

Comparison of blue laser and red light-emitting diode-mediated aminolevulinic acid-based photodynamic therapy for moderate and severe acne vulgaris: A prospective, split-face, nonrandomized controlled study

BACKGROUND

Acne is a chronic inflammatory skin disease. Photodynamic therapy (PDT) is a highly effective and safe drug-device combination treatment, typically using red and blue light. However, direct comparisons of aminolevulinic acid (ALA)-based PDT using these two light sources are lacking. Therefore, we compared the efficacy and adverse effects of ALA-based 450 nm blue laser-mediated PDT (BL-PDT) and 630 ± 10 nm red light-emitting diode-mediated PDT (RL-PDT) in the treatment of moderate-to-severe acne vulgaris, including analyses of different lesion types.

METHODS

Sixteen patients with moderate-to-severe acne vulgaris were recruited. All patients underwent BL-PDT on the left side of the face and RL-PDT on the right side. Treatments were administered thrice at 2-week intervals, and follow-up continued for 2 weeks after the final treatment. The average rates of improvement in inflammatory and non-inflammatory acne lesions, IGA (Investigator's Global Assessment) scales, and IGA success rates were calculated. In addition, adverse effects during and after each treatment were recorded.

RESULTS

At the 2-week follow-up after the final treatment, the average rates of improvement in total acne, inflammatory, and non-inflammatory lesions were 48.0 %, 63.0 %, and 30.0 % in the BL-PDT group and 42.2 %, 58.1 %, and 27.5 % in the RL-PDT group, respectively. The IGA scores for the two groups decreased by 1.8 and 1.7 points, respectively, and the IGA success rate was 53.3 % in both groups. There were no significant differences between the BL-PDT and RL-PDT groups in any measure of effectiveness. However, the BL-PDT group exhibited more severe adverse effects, especially pain and hyperpigmentation.

CONCLUSIONS

BL-PDT and RL-PDT have similar efficacies in moderate-to-severe acne vulgaris and are particularly effective for inflammatory acne lesions. RL-PDT benefits from milder adverse effects than those of BL-PDT.

Modulation of Photosensitizing Responses in Cell Culture Environments by Different Medium Components

Many cell culture experiments are performed under light to evaluate the photodynamic or photosensitizing efficacy of various agents. In this study, the modulation of photosensitizing responses and phototoxicity under cell culture conditions by different medium components was investigated. The significant levels of reactive oxygen species (ROS) generated from DMEM, RPMI 1640, and MEM were observed under the irradiation of fluorescent light (FL) and white and blue LEDs, indicating that these media have their own photosensitizing properties; DMEM showed the most potent property. Phenol red-free DMEM (Pf-D) exhibited a stronger photosensitizing property than normal DMEM by 1.31 and 1.25 times under FL and blue LEDs, respectively; phenol red and riboflavin-free DMEM (PRbf-D) did not show any photosensitizing properties. The inhibitory effect on light transmission was more pronounced in DMEM than in RPMI, and the interference effect on green LED light was greatest at 57.8 and 27.4%, respectively; the effect disappeared in Pf-D. The media containing riboflavin induced strong phototoxicity in HaCaT keratinocytes by generating H2O2 under light irradiation, which was quenched by sodium pyruvate in the media. The presence of serum in the media was also reduced the phototoxicity; H2O2 levels in the media decreased serum content dependently. The phototoxicity of erythrosine B and protoporphyrin IX under FL was more sensitively pronounced in PRbf-D than in DMEM. The present results indicate that several medium components, including riboflavin, phenol red, sodium pyruvate, and serum, could modulate photosensitizing responses in a cell culture system by inducing photosensitizing activation and by interfering with irradiation efficacy and ROS generation.

Insights from Traditional Chinese Medicine for Restoring Skin Barrier Functions

The skin barrier is essential for maintaining the body's internal homeostasis, protecting against harmful external substances, and regulating water and electrolyte balance. Traditional Chinese Medicine (TCM) offers notable advantages in restoring skin barrier function due to its diverse components, targets, and pathways. Recent studies have demonstrated that active ingredients in TCM can safely and effectively repair damaged skin barriers, reinstating their proper functions. This review article provides a comprehensive overview of the mechanisms underlying skin barrier damage and explores how the bioactive constituents of TCM contribute to skin barrier repair, thereby offering a theoretical framework to inform clinical practices.

Dual-Modal Near-Infrared Organic Nanoparticles: Integrating Mild Hyperthermia Phototherapy with Fluorescence Imaging

Purpose

Our study seeks to develop dual-modal organic-nanoagents for cancer therapy and real-time fluorescence imaging, followed by their pre-clinical evaluation on a murine model. Integrating NIR molecular imaging with nanotechnology, our aim is to improve outcomes for early-stage cutaneous melanoma by offering more effective and less invasive methods. This approach has the potential to enhance both photothermal therapy (PTT) and Sentinel Lymph Node Biopsy (SLNB) procedures for melanoma patients.

Methods

NIR-797-isothiocyanate was encapsulated in poly(D,L-lactide-co-glycolide) acid (PLGA) nanoparticles (NPs) using a two-step protocol, followed by thorough characterization, including assessing loading efficiency, fluorescence stability, and photothermal conversion. Biocompatibility and cellular uptake were tested in vitro on melanoma cells, while PTT assay, with real-time thermal monitoring, was performed in vivo on tumor-bearing mice under irradiation with an 808 nm laser. Finally, ex vivo fluorescence microscopy, histopathological assay, and TEM imaging were performed.

Results

Our PLGA NPs, with a diameter of 270 nm, negative charge, and 60% NIR-797 loading efficiency, demonstrated excellent stability and fluorescence properties, as well as efficient light-to-heat conversion. In vitro studies confirmed their biocompatibility and cellular internalization. In vivo experiments demonstrated their efficacy as photothermal agents, inducing mild hyperthermia with temperatures reaching up to 43.8 °C. Ex vivo microscopy of tumor tissue confirmed persistent NIR fluorescence and uniform distribution of the NPs. Histopathological and TEM assays revealed early apoptosis, immune cell response, ultrastructural damage, and intracellular material debris resulting from combined NP treatment and irradiation. Additionally, TEM analyses of irradiated zone margins showed attenuated cellular damage, highlighting the precision and effectiveness of our targeted treatment approach.

Conclusion

Specifically tailored for dual-modal NIR functionality, our NPs offer a novel approach in cancer PTT and real-time fluorescence monitoring, signaling a promising avenue toward clinical translation.

Light-emitting diode irradiation at 590 nm combined with active substances modulates ultraviolet B radiation-induced keratinocyte inflammation

To evaluate the efficacy of yellow light-emitting diode (LED) irradiation at 590 nm, alone or in combination with anti-inflammatory active substances against ultraviolet (UV)-induced inflammation in keratinocytes. HaCaT keratinocytes were pretreated with LED yellow light (590 nm) alone or in combination with an antiinflammatory active substance such as glycerophosphoinositol choline (GC), extract of grains of paradise (Aframomum melegueta Schum, AM), or a bisabolol and ginger root extract mixture (Bb-GE) before UVB irradiation. Following each treatment, we measured the levels of inflammatory mediators secreted by keratinocytes. HaCaT keratinocytes treated with UVB (300 mJ cm-²) and then cultured for 24 h exhibited significantly upregulated expression of proinflammatory factors, including interleukin (IL)-1α, prostaglandin E2 (PGE2), and IL-8. After pretreatment with 590 nm LED, UVB-induced inflammatory responses were significantly inhibited. Co-pretreatment with 590 nm LED irradiation and GC further inhibited the expression of IL-1α and IL-8. IL-8 expression was inhibited by co-pretreatment with 590 nm LED irradiation and AM, whereas PGE2 expression was inhibited by co-pretreatment with 590 nm LED irradiation and Bb-GE. Co-treatment with 590 nm LED irradiation and various active substances modulated UVB-induced inflammation in keratinocytes, suggesting the potential application of this approach to prevent damage caused by voluntary sun exposure in daily life.

Physical Treatments and Therapies for Androgenetic Alopecia

Androgenetic alopecia, the most common cause of hair loss affecting both men and women, is typically treated using pharmaceutical options, such as minoxidil and finasteride. While these medications work for many individuals, they are not suitable options for all. To date, the only non-pharmaceutical option that the United States Food and Drug Administration has cleared as a treatment for androgenetic alopecia is low-level laser therapy (LLLT). Numerous clinical trials utilizing LLLT devices of various types are available. However, a myriad of other physical treatments for this form of hair loss have been reported in the literature. This review evaluated the effectiveness of microneedling, pulsed electromagnetic field (PEMF) therapy, low-level laser therapy (LLLT), fractional laser therapy, and nonablative laser therapy for the treatment of androgenetic alopecia (AGA). It also explores the potential of multimodal treatments combining these physical therapies. The majority of evidence in the literature supports LLLT as a physical therapy for androgenetic alopecia. However, other physical treatments, such as nonablative laser treatments, and multimodal approaches, such as PEMF-LLLT, seem to have the potential to be equally or more promising and merit further exploration.

Age dependency of the reduced scattering coefficient and viscoelastic character, and their relationship in Japanese female skin

We measured the reduced scattering coefficient (µs') with the edge-loss method at skin sites on the faces and upper arms of Japanese females aged 20s to 50s, and observed significant negative correlations at all sites, including the mouth. At the same mouth site, we also measured the viscoelastic properties with a Cutometer MPA580 and evaluated their correlation with µs'. Significant correlations were observed for the parameters of pliability, the portion of the viscoelasticity during the suction phase, and total recovery from the Cutometer against µs' with the effect of age removed. The results experimentally suggest the relation between µs' and the collagen condition.

Photo-Driven Ion Directional Transport across Artificial Ion Channels: Band Engineering of WS2 via Peptide Modification

Biological photo-responsive ion channels play important roles in the important metabolic processes of living beings. To mimic the unique functions of biological prototypes, the transition metal dichalcogenides, owing to their excellent mechanical, electrical, and optical properties, are already used for artificial intelligent channel constructions. However, there remain challenges to building artificial bio-semiconductor nanochannels with finely tuned band gaps for accurately simulating or regulating ion transport. Here, two well-designed peptides are employed for the WS2 nanosheets functionalization with the sequences of PFPFPFPFC and DFDFDFDFC (PFC and DFC; P: proline, D: aspartate, and F: phenylalanine) through cysteine (Cys, C) linker, and an asymmetric peptide-WS2 membrane (AP-WS2M) could be obtained via self-assembly of peptide-WS2 nanosheets. The AP-WS2M could realize the photo-driven anti-gradient ion transport and vis-light enhanced osmotic energy conversion by well-designed working patterns. The photo-driven ion transport mechanism stems from a built-in photovoltaic motive force with the help of formed type II band alignment between the PFC-WS2 and DFC-WS2. As a result, the ions would be driven across the channels of the membrane for different applications. The proposed system provides an effective solution for building photo-driven biomimetic 2D bio-semiconductor ion channels, which could be extensively applied in the fields of drug delivery, desalination, and energy conversion.

Photoprotection: Current developments and controversies

This review aimed at summarizing some of the key points that were discussed during the photoprotection session at the International Forum of Dermatology in 2022. This international conference was designed to address prominent topics of clinical dermatology in a holistic way, allowing to articulate multiple viewpoints. Therefore, this review does not claim to be exhaustive, but is instead intended to give an overview of recent developments and ongoing controversies in the field of photoprotection. Cumulative ultraviolet radiation (UVR) exposure is the major aetiological factor in the development of photoageing, photoimunosuppression and photocarcinogenesis. UVA (320-400 nm) penetrates into the dermis and damages DNA and other intracellular and acellular targets primarily by generating reactive oxygen species (ROS). It is the major contributor to photoageing, characterized by fine and coarse wrinkles, dyspigmentation and loss of elasticity. UVB (290-320 nm) is responsible for sunburns through direct damage to DNA by the formation of 6-4 cyclobutane pyrimidine dimers (CPDs) and pyrimidine 6-4 pyrimidone photoproducts. Both UVA and UVB exposure increase the risk of basal cell carcinoma, squamous cell carcinoma and melanoma. In recent years, visible light (VL; 400-700 nm) has also been implicated in the exacerbation of conditions aggravated by sun exposure such as hyperpigmentation and melasma. Photoprotection is a critical health strategy to reduce the deleterious effects of UVR and VL. Comprehensive photoprotection strategies include staying in the shade when outdoors, wearing photoprotective clothing including a wide-brimmed hat, and sunglasses, and the use of sunscreen. Due to the absorption of UV filters, the safety of sunscreens has been questioned. Newer sunscreens are becoming available with filters with absorption even beyond the UV spectrum, offering enhanced protection compared with older products. Prevention of photocarcinogenesis, sun-induced or sunlight-exacerbated hyperpigmentary conditions and drug-induced photosensitivity is an important reason for adopting comprehensive photoprotection strategies.

Evaluation of thermal shock therapy for reducing pain during intense pulsed light therapy: An intrapatient randomized controlled study

BACKGROUND

Intense pulsed light (IPL) is used for the treatment and improvement of various skin issues. However, patients often experience local skin burning and pain after IPL treatment. Cooling and analgesic measures are indispensable.

AIMS

To investigate the clinical effect of thermal shock therapy on pain relief and reduction of adverse reactions during IPL therapy.

PATIENTS/METHODS

A total of 60 female patients with facial photoaging who received IPL therapy were enrolled in the study. As a comparative split-face study, one side of the face was randomly selected as the control side. The other side was given thermal shock therapy before and after the IPL treatment immediately as analgesic side. The visual analog scale (VAS) was used to evaluate the pain degree of the patients. The telephone follow-ups regarding the occurrence of adverse reactions were conducted respectively on the 2nd day, 7th day, and 1 month after treatment.

RESULTS

The VAS score and skin temperature of analgesia side was lower than that of control side at different stages of treatment. In terms of adverse reactions, the incidence of transient facial redness on the analgesic side was lower than that on the control side. Two patients showed slight secondary pigmentation on the control side, and the other patients showed no other adverse reactions on both sides.

CONCLUSIONS

Thermal shock therapy assisted IPL therapy can reduce skin temperature during treatment, effectively relieve patients' pain, reduce the occurrence of adverse reactions caused by heat injury, and improve patients' comfort level.

Understanding Active Photoprotection: DNA-Repair Enzymes and Antioxidants

The detrimental effects of ultraviolet radiation (UVR) on human skin are well-documented, encompassing DNA damage, oxidative stress, and an increased risk of carcinogenesis. Conventional photoprotective measures predominantly rely on filters, which scatter or absorb UV radiation, yet fail to address the cellular damage incurred post-exposure. To fill this gap, antioxidant molecules and DNA-repair enzymes have been extensively researched, offering a paradigm shift towards active photoprotection capable of both preventing and reversing UV-induced damage. In the current review, we focused on "active photoprotection", assessing the state-of-the-art, latest advancements and scientific data from clinical trials and in vivo models concerning the use of DNA-repair enzymes and naturally occurring antioxidant molecules.

The spinning disc reactor for photocatalytic degradation: A systematic review

In recent years, the use of a horizontal spinning disc reactor (SDR) as a photocatalytic reactor for the degradation of various pollutants in aqueous solutions has increased. This study was searched based on the PRISMA method. Two autonomous researchers carried out for the relevant studies using Scopus, Web of Science (WOS), and Science Direct databases. The search terms expanded focusing on the performance of horizontal spinning disc photocatalytic reactor (SDPR). In this review article, the main objective of the effect of operational factors on the efficiency of the degradation of pollutants with changes in the type of light source (range of visible light and UV radiation), disc rotational speed, flow rate, initial concentration of pollutants, pH, type of disc structure and flow regime are considered. Current challenges in SDPR include issues such as limited mass transfer, uneven light distribution, and difficulties in scaling up. To overcome these challenges, improvements can be made by optimizing reactor design for better mass transfer, enhancing light distribution through advanced light sources or reactor configurations, and developing scalable models that maintain efficiency at larger scales. Additionally, the use of innovative materials and coatings could improve the overall performance of SDPR.

Beyond Traditional Sunscreens: A Review of Liposomal-Based Systems for Photoprotection

Sunscreen products are essential for shielding the skin from ultraviolet (UV) radiation, a leading cause of skin cancer. While existing products serve this purpose, there is a growing need to enhance their efficacy while minimizing potential systemic absorption of UV filters and associated toxicological risks. Liposomal-based formulations have emerged as a promising approach to address these challenges and develop advanced photoprotective products. These vesicular systems offer versatility in carrying both hydrophilic and lipophilic UV filters, enabling the creation of broad-spectrum sunscreens. Moreover, their composition based on phospholipids, resembling that of the stratum corneum, facilitates adherence to the skin's surface layers, thereby improving photoprotective efficacy. The research discussed in this review underscores the significant advantages of liposomes in photoprotection, including their ability to limit the systemic absorption of UV filters, enhance formulation stability, and augment photoprotective effects. However, despite these benefits, there remains a notable gap between the potential of liposomal systems and their utilization in sunscreen development. Consequently, this review emphasizes the importance of leveraging liposomes and related vesicular systems as innovative tools for crafting novel and more efficient photoprotective formulations.

Assessing the efficacy of a 100 ps Nd:YAG laser for tattoo removal in a minipig model

Using a minipig model, we evaluated the efficacy of the 100 ps Nd:YAG laser in the removal of tattoo pigments, specifically blue, green, red, and yellow. We observed distinct pigment responses to 532/1064 nm wavelengths at various energy settings. Through a combination of clinical, spectroscopic, and histological methods, we found the 532 nm wavelength to be most effective in disrupting all colors, with notable results for green and yellow at 0.4 J/cm2 and red at 0.72 J/cm2. The 1064 nm wavelength reduced pigment in yellow (1.51 J/cm2), green (1.35 J/cm2), and blue (1.11 J/cm2) tattoos, but was surpassed by the 532 nm in efficiency. Our data underscores the crucial interplay between pigment traits and laser settings in tattoo removal. We advocate for tailored treatment strategies, integrating pigment hue and laser wavelength, to enhance removal outcomes.

Natural Phytochemical and Visible Light at Different Wavelengths Show Synergistic Antibacterial Activity against Staphylococcus aureus

As the risk of antibiotic-resistant bacteria increases, interest in non-antibiotic treatment is also increasing. Among the methods used in non-antibiotic therapy, natural antibiotics such as essential oils have disadvantages such as low efficiency. In the case of phototherapy, the light used for antibacterial activities has low penetration into the human body because of its short wavelength, making it of low medical utility. To solve this problem, this study aimed to determine conditions for enhancing the antibacterial activity of natural phytochemicals and visible light. Four natural phytochemical extracts that showed high antibacterial properties in previous studies were analyzed. Synergistic effects on antibacterial activity and cytotoxicity were determined when natural phytochemical extracts and visible light were simultaneously used. As a result, it was confirmed that the antibacterial activity increased by four times when Sanguisorba officinalis L. was irradiated with 465 nm for 10 min and 520 nm for 40 min, and Uncaria gambir Roxb. was irradiated with 465 nm for 10 min and 520 nm for 60 min compared to when Sanguisorba officinalis L. and Uncaria gambir Roxb. were used alone. The synergistic effect on antibacterial activity was independent of the absorption peak of the natural phytochemical extracts. In addition, in the case of natural phytochemical extracts with improved antibacterial activity, it was confirmed that the improvement of antibacterial activity was increased in inverse proportion to the light irradiation wavelength and in proportion to the light irradiation time. The antibacterial activity was enhanced regardless of antibiotic resistance. In the case of cytotoxicity, it was confirmed that there was no toxicity to A549 cells when treated with 465 nm, the shortest wavelength among the natural phytochemical extracts. These results show how to replace blue light, which has been underutilized due to its low transmittance and cytotoxicity. They also demonstrate the high medical potential of using natural phytochemical and visible light as a combination therapy.

Acne treatment challenges - Recommendations of Latin American expert consensus

BACKGROUND

Acne is a chronic inflammatory disorder of the pilosebaceous unit that is associated with a negative impact on quality of life, causing anxiety, depression, and poor self-esteem. The treatment of acne is not simple and presents some new challenges. This article addresses important issues faced by dermatologists on their daily, some of them specific for Latin America.

OBJECTIVE

To discuss daily practice recommendations when managing acne patients.

METHODS

A literature review was conducted by a group of eight experts with extensive experience in the field of acne. The results of the data review were presented at an initial kick-off meeting to align the consensus topics. Two e-surveys using the Delphi methodology and an interim group webinar meeting were held.

RESULTS

The expert panel reached a consensus on all proposed key statements, providing scientific support to help dermatologists and healthcare providers make acne management decisions on topics that can be challenging in the everyday practice of dermatology, such as the characteristics of Generation Z or the importance of the maintenance phase of adult acne treatment.

CONCLUSION

This article provides current recommendations for managing acne patients. The high level of agreement achieved based on the latest evidence supports the best acne therapeutic choices in both established topics and new important issues that have emerged in recent years, such as the impact of social media, Generation Z characteristics, and transgender male patient specifics.

Spatially modulated ablation driven by chaotic attractors in human lung epithelial cancer cells

A significant modification in photoinduced energy transfer in cancer cells is reported by the assistance of a dynamic modulation of the beam size of laser irradiation. Human lung epithelial cancer cells in monolayer form were studied. In contrast to the quantum and thermal ablation effect promoted by a standard focused Gaussian beam, a spatially modulated beam can caused around 15% of decrease in the ablation threshold and formation of a ring-shaped distribution of the photothermal transfer effect. Optical irradiation was conducted in A549 cells by a 532 nm single-beam emerging from a Nd:YVO4 system. Ablation effects derived from spatially modulated convergent waves were controlled by an electrically focus-tunable lens. The proposed chaotic behavior of the spatial modulation followed an Arneodo chaotic oscillator. Fractional dynamic thermal transport was analyzed in order to describe photoenergy in propagation through the samples. Immediate applications of chaos theory for developing phototechnology devices driving biological functions or phototherapy treatments can be considered.

Unlocking the Power of Light on the Skin: A Comprehensive Review on Photobiomodulation

Photobiomodulation (PBM) is a procedure that uses light to modulate cellular functions and biological processes. Over the past decades, PBM has gained considerable attention for its potential in various medical applications due to its non-invasive nature and minimal side effects. We conducted a narrative review including articles about photobiomodulation, LED light therapy or low-level laser therapy and their applications on dermatology published over the last 6 years, encompassing research studies, clinical trials, and technological developments. This review highlights the mechanisms of action underlying PBM, including the interaction with cellular chromophores and the activation of intracellular signaling pathways. The evidence from clinical trials and experimental studies to evaluate the efficacy of PBM in clinical practice is summarized with a special emphasis on dermatology. Furthermore, advancements in PBM technology, such as novel light sources and treatment protocols, are discussed in the context of optimizing therapeutic outcomes and improving patient care. This narrative review underscores the promising role of PBM as a non-invasive therapeutic approach with broad clinical applicability. Despite the need for further research to develop standard protocols, PBM holds great potential for addressing a wide range of medical conditions and enhancing patient outcomes in modern healthcare practice.

Enhancement of skin rejuvenation and hair growth through novel near-infrared light emitting diode (nNIR) lighting: in vitro and in vivo study

The study aimed to explore the impact of a novel near-infrared LED (nNIR) with an extended spectrum on skin enhancement and hair growth. Various LED sources, including White and nNIRs, were compared across multiple parameters: cytotoxicity, adenosine triphosphate (ATP) synthesis, reactive oxygen species (ROS) reduction, skin thickness, collagen synthesis, collagenase expression, and hair follicle growth. Experiments were conducted on human skin cells and animal models. Cytotoxicity, ATP synthesis, and ROS reduction were evaluated in human skin cells exposed to nNIRs and Whites. LED irradiation effects were also studied on a UV-induced photoaging mouse model, analyzing skin thickness, collagen synthesis, and collagenase expression. Hair growth promotion was examined as well. Results revealed both White and nNIR were non-cytotoxic to human skin cells. nNIR enhanced ATP and collagen synthesis while reducing ROS levels, outperforming the commonly used 2chip LEDs. In the UV-induced photoaging mouse model, nNIR irradiation led to reduced skin thickness, increased collagen synthesis, and lowered collagenase expression. Additionally, nNIR irradiation stimulated hair growth, augmented skin thickness, and increased hair follicle count. In conclusion, the study highlighted positive effects of White and nNIR irradiation on skin and hair growth. However, nNIR exhibited superior outcomes compared to White. Its advancements in ATP content, collagen synthesis, collagenase inhibition, and hair growth promotion imply increased ATP synthesis activity. These findings underscore nNIR therapy's potential as an innovative and effective approach for enhancing skin and promoting hair growth.

Integrated sun protection advice for the South African population

Exposure to solar ultraviolet radiation (UVR) is associated with several cutaneous adverse effects. However, to the best of our knowledge, in South Africa there are no formal guidelines on sun protection. A group of South African dermatologists and researchers convened over the course of 1 year to deliberate on integrated advice for sun protection among the multi-ethnic South African population. For people with light skin and those with genetic skin disorders (e.g., oculocutaneous albinism), sun protection was identified as critical to prevent sunburn, skin cancer, and photoaging. The evidence is less clear for people with medium and darker skin types, especially the latter, in whom melanin may confer a degree of protection against some parts of the solar spectrum. Recent studies have demonstrated that visible light can cause pigmentary changes in individuals with darker skin types in particular. Sun protection for people of all skin colors is beneficial to protect against photoaging and ocular damage. Herein sun protection advice is suggested for South Africans of all skin colors to reduce morbidity and mortality from sun exposure, particularly relating to skin cancer. Several knowledge gaps are identified as future research priorities.

Guide to tinted sunscreens in skin of color

Disorders of hyperpigmentation, such as melasma and post-inflammatory hyperpigmentation, disproportionately affect skin of color and have a profound impact on quality of life. Exposure to ultraviolet light (UVL) is a well-documented factor in these disorders. However, recent studies show that visible light (VL) is a significant and underrecognized contributor to hyperpigmentation, especially in skin of color. Our objective is to review the role of VL in disorders of hyperpigmentation and that of tinted sunscreens in protecting against VL. Tinted sunscreens containing iron oxides should be recommended over nontinted sunscreens for patients prone to disorders of hyperpigmentation, as iron oxides protect against VL in addition to UVL. Tinted sunscreens are more effective than nontinted sunscreens in preventing melasma relapses and reducing hyperpigmentation, and they may also enhance the depigmenting efficacy of topical hydroquinone. In the search for an ideal tinted sunscreen for a particular patient, several factors must be considered, including a broad spectrum with adequate coverage of both UVL and VL, tint, formulation texture, active ingredients, and cost. VL is increasingly recognized as a major contributor of hyperpigmentation, and adequate treatment for disorders of hyperpigmentation should include protection against VL. Tinted sunscreens are ideal but require consideration of cosmesis, efficacy, and affordability.

Potassium permanganate oxidation enhanced by infrared light and its application to natural water

Photocoupled permanganate (PM) is an effective way to enhance the oxidation efficiency of PM, however, the activation of PM by infrared has received little attention. This study aimed to investigate the ability of infrared light to activate PM. When coupled with infrared, the degradation rate of 4-chlorophenol (4-CP) is increased to 3.54 times of PM oxidation alone. The accelerated reaction was due to the formation of vibrationally excited PM by absorbing 3.1 kJ mol-1 infrared energy, which also leads to the primary reactive intermediates Mn(V/IV) in the reaction system. The infrared coupled PM system also showed 1.14-2.34 times promotion effect on other organic pollutants. Furthermore, solar composed of 45% infrared, coupled PM system showed excellent degradation performance, where the degradation of 4-CP in 10 L of tap water and river water was 68 and 23 times faster than in ultrapure water, respectively. The faster-increased degradation rate in natural waters is mainly due to the abundant inorganic ions, which can stabilize the manganese species, and then has a positive effect on 4-CP degradation. In summary, this work develops a energy-efficient photoactivated PM technology that utilizes infrared and provides new insights into the design of novel sunlight-powered oxidation processes for water treatment.

Effects of low‑power red laser and blue LED on mRNA levels from DNA repair genes in human breast cancer cells

Photobiomodulation (PBM) induced by non-ionizing radiations emitted from low-power lasers and light-emitting diodes (LEDs) has been used for various therapeutic purposes due to its molecular, cellular, and systemic effects. At the molecular level, experimental data have suggested that PBM modulates base excision repair (BER), which is responsible for restoring DNA damage. There is a relationship between the misfunction of the BER DNA repair pathway and the development of tumors, including breast cancer. However, the effects of PBM on cancer cells have been controversial. Breast cancer (BC) is the main public health problem in the world and is the most diagnosed type of cancer among women worldwide. Therefore, the evaluation of new strategies, such as PBM, could increase knowledge about BC and improve therapies against BC. Thus, this work aims to evaluate the effects of low-power red laser (658 nm) and blue LED (470 nm) on the mRNA levels from BER genes in human breast cancer cells. MCF-7 and MDA-MB-231 cells were irradiated with a low-power red laser (69 J cm-2, 0.77 W cm-2) and blue LED (482 J cm-2, 5.35 W cm-2), alone or in combination, and the relative mRNA levels of the APTX, PolB, and PCNA genes were assessed by reverse transcription-quantitative polymerase chain reaction. The results suggested that exposure to low-power red laser and blue LED decreased the mRNA levels from APTX, PolB, and PCNA genes in human breast cancer cells. Our research shows that photobiomodulation induced by low-power red laser and blue LED decreases the mRNA levels of repair genes from the base excision repair pathway in MCF-7 and MDA-MB-231 cells.

Phototherapy for age-related brain diseases: Challenges, successes and future

Brain diseases present a significant obstacle to both global health and economic progress, owing to their elusive pathogenesis and the limited effectiveness of pharmaceutical interventions. Phototherapy has emerged as a promising non-invasive therapeutic modality for addressing age-related brain disorders, including stroke, Alzheimer's disease (AD), and Parkinson's disease (PD), among others. This review examines the recent progressions in phototherapeutic interventions. Firstly, the article elucidates the various wavelengths of visible light that possess the capability to penetrate the skin and skull, as well as the pathways of light stimulation, encompassing the eyes, skin, veins, and skull. Secondly, it deliberates on the molecular mechanisms of visible light on photosensitive proteins, within the context of brain disorders and other molecular pathways of light modulation. Lastly, the practical application of phototherapy in diverse clinical neurological disorders is indicated. Additionally, this review presents novel approaches that combine phototherapy and pharmacological interventions. Moreover, it outlines the limitations of phototherapeutics and proposes innovative strategies to improve the treatment of cerebral disorders.

Near-infrared light does not induce DNA damage in human dermal fibroblasts

Photobiomodulation (PBM) can be used to treat a range of conditions in dermatology. PBM refers to the changes induced by red (RL, 620-700 nm) and near-infrared (NIR, 700-1440 nm) light. Light radiation-induced DNA damage is a major contributor to aging and skin cancer. It is crucial to study the effects of PBM on DNA to ensure safety. Our lab previously demonstrated that RL (633 ± 6 nm) did not result in human dermal fibroblasts (HDFs) DNA damage. This study employed similar methods to investigate NIR effects. Commercially available LED-NIR (830 ± 5 nm) panels (66, 132, and 264 J/cm2 ) did not result in DNA damage measured by cyclobutane pyrimidine dimers and pyrimidine-6,4-pyrimidone photoproducts in HDFs compared to temperature-matched controls immediately, 3 h, and 24 h following irradiation and compared to positive and negative controls. This demonstrates that LED-NIR does not damage DNA in HDFs in vitro.