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Light-emitting diode photobiomodulation is the newest category of nonthermal light therapies to find its way to the dermatologic armamentarium. In this article, we briefly review the literature on the development of this technology, its evolution within esthetic and medical dermatology, and provide practical and technical considerations for use in...
Citations
... Interestingly, after comparing the contractile force of the skeletal muscle under frequencies of 1, 2, and 4 Hz, the results showed that the contractile force decreased with the stimulating frequency. Furthermore, the penetration depth of 470-nm light into biological tissues is limited to 500-740 lm, 38,39 which scopes the range of the muscle thickness effectively activated in the biohybrid robot. ...
Biohybrid robots have attracted many researchers' attention due to their high flexibility, adaptation ability, and high output efficiency. Under electrical, optical, and neural stimulations, the biohybrid robot can achieve various movements. However, better understanding and more precise control of the biohybrid robot are strongly needed to establish an integrated autonomous robotic system. In this review, we outlined the ongoing techniques aiming for the contraction model and accurate control for the biohybrid robot. Computational modeling tools help to construct the bedrock of the contraction mechanism. Selective control, closed-loop control, and on-board control bring new perspectives to realize accurate control of the biohybrid robot. Additionally, applications of the biohybrid robot are given to indicate the future direction in this field.
... UV light has the most shallow penetration; when separated to UVC (100-280 nm), UVB (280-320 nm) and UVA(320-400 nm), only UVA can reach to the very depths of the epidermis, which is the most superficial layer of skin with a less than 1 mm of thickness [109]. Blue (400-470 nm) and green (470-550 nm) light can only penetrate skin thickness between 0.5 and 2 mm [110]; and these wavelengths activate several important photoswitches like CRY2, LOV2, and ChR2 [111] which may lead to the necessity of an external light source, causing difficulties in awake animals [112]. Yellow/orange (550-630 nm) and red (630-700) light can penetrate deeper, between 1 to 6 mm skin thickness, reaching below the dermis even in thick skin, and IR light (700-1000 nm) has the maximum penetration of all light wavelengths, transmitting past even bone to reach deeper tissues [110,113]. ...
... Blue (400-470 nm) and green (470-550 nm) light can only penetrate skin thickness between 0.5 and 2 mm [110]; and these wavelengths activate several important photoswitches like CRY2, LOV2, and ChR2 [111] which may lead to the necessity of an external light source, causing difficulties in awake animals [112]. Yellow/orange (550-630 nm) and red (630-700) light can penetrate deeper, between 1 to 6 mm skin thickness, reaching below the dermis even in thick skin, and IR light (700-1000 nm) has the maximum penetration of all light wavelengths, transmitting past even bone to reach deeper tissues [110,113]. Specific wavelength ranges to optimally reach different areas of skin and connective tissue can especially be found in literature of dermal phototherapy. ...
... The intensity, beam width, and duration of the light beam utilized can also affect the penetration depth of light. Increased beam width can lead to greater penetration of the central photons up to a limit (beam width of 10 mm) where the maximal penetration is reached [111], while short pulses of light can in some circumstances reach deeper in the tissue than continuous light [110]. ...
Optogenetics, a revolutionary technique leveraging light stimulation for precise cellular control, holds immense potential in regenerative medicine. Offering unparalleled spatial and temporal accuracy, the entrance of optogenetics into tissue engineering and regenerative medicine (TERM) empowers researchers to modify genes precisely and reversibly, control signal pathways and antibodies, as well as alter biomaterial properties. Optogenetics provides unprecedented control in the manipulation of physiological regeneration, replication of intricate developmental processes, and tissue engineering in a laboratory setting. Although further investigation is required for the safe and feasible injection of optogenetic systems into human bodies, the use of optogenetics has already led to a great amount of research on several tissues and systems. It has found diverse applications in TERM of skin and connective tissue, endothelium, bone, cartilage, and muscle; with researchers leveraging optogenetics for precise control over the in vitro or in vivo production of these tissues, the investigation of critical proteins and pathways, the creation of light‐controlled wound coverings and even as a tool for directional tissue growth in living subjects. Optogenetics emerges as a transformative force in shaping the future of medical science, demonstrating a pivotal role in advancing regenerative medicine and paving the way for innovative therapeutic strategies.
... Apart from TME level, tissue penetration depth of light is critical for PDT [95,96]. Conventional PSs are typically activated by short-wavelength ultraviolet-visible (UV-Vis) light, limiting their effectiveness in treating deep-seated tumors due to insufficient tissue penetration [97]. To address this, various approaches, including near-infrared (NIR) light, X-ray radiation, and self-luminescence have been explored [98]. ...
Photodynamic therapy (PDT) represents a targeted approach for cancer treatment that employs light and photosensitizers (PSs) to induce the generation of reactive oxygen species (ROS). However, PDT faces obstacles including insufficient PS localization, limited light penetration, and treatment resistance. A potential solution lies in nanogenerators (NGs), which function as self-powered systems capable of generating electrical energy. Recent progress in piezoelectric and triboelectric NGs showcases promising applications in cancer research and drug delivery. Integration of NGs with PDT holds the promise of enhancing treatment efficacy by ensuring sustained PS illumination, enabling direct electrical control of cancer cells, and facilitating improved drug administration. This comprehensive review aims to augment our comprehension of PDT principles, explore associated challenges, and underscore the transformative capacity of NGs in conjunction with PDT. By harnessing NG technology alongside PDT, significant advancement in cancer treatment can be realized. Herein, we present the principal findings and conclusions of this study, offering valuable insights into the integration of NGs to overcome barriers in PDT.
... In recent years, light-emitting diode (LED) light sources have become increasingly popular for treating dermatological conditions [5]. Unlike high-powered lasers, which focus on a localized area, LED light sources can effectively treat large areas of skin with an appropriate light output. ...
Background
Light‐emitting diode (LED) light sources have become an increasingly popular choice for the treatment and rejuvenation of various dermatological conditions.
Aims
This study aimed to evaluate the effects of neck rejuvenation, patient satisfaction, and the safety of LED application to the neck in an Asian population.
Methods
This was a multicenter, randomized, double‐blind, sham device study. Seventy participants were enrolled in the study. The participants wore the home‐use LED neck device for 9 min a day, 5 times a week, for a total of 60 sessions. The Lemperle Wrinkle Scale (LWS) and Global Aesthetic Improvement Scale (GAIS) were used to evaluate the results of both investigators and participants. The thyroid gland was examined using ultrasonography to evaluate the safety of the investigational device.
Results
The percentage of participants with improved LWS at Week 12 was significantly higher in the study group. Additionally, the percentage of participants with improved LWS was significantly higher in the study group at Weeks 8, 12, and 16. The LWS at Week 12 corrected with baseline values was found to be significantly different between the two groups. GAIS showed significant differences at 8, 12, and 16 weeks in the investigators' evaluation but not in the participants' evaluation. Repeated‐measures analysis of variance at Weeks 4, 8, 12, and 16 also confirmed a significant difference between the two groups only in investigator assessment. No significant thyroid‐related complications were observed.
Conclusion
LED application to the neck may be considered a satisfactory and safe procedure for neck rejuvenation.
... Meanwhile, the wavelength is an important parameter to assess how light is emitted and how it will interact with the tissue. In the case of lasers used in photomedicine, the wavelength is measured in nanometers (nm) or micrometers (µm) [36]. Wavelength and energy are properties inversely proportional, which means that the smaller the wavelength, the greater the frequency of the waves and the energy of the photons [37]. ...
Major depressive disorder (MDD) is a prevalent mental health condition affecting a significant portion of the population worldwide. This condition can impact individuals of all ages, including adolescents, leading to an impact on various aspects of their lives. Adolescence is a crucial phase of human development, characterized by several neurobiological changes. The onset of MDD during this period can result in damage not only to teenagers but also might have long-lasting implications for their future as adults. Notably, the onset of MDD in adolescents is often associated with various biomarkers, such as increased levels of inflammatory cytokines (e.g., IL-6, TNF-α), oxidative stress markers, and alterations in neurotransmitter levels, indicating a complex interplay of biological factors. Therefore, early intervention is essential for addressing MDD during this phase. Photobiomodulation therapy (PBMT) emerges as an innovative and promising approach that utilizes light, especially in the near-infrared (NIR) and red spectra, to trigger biological and therapeutic effects. Notably, targeting the skull and abdomen with PBMT might explore the bidirectional communication between the intestinal system and the central nervous system in a remote and/or systemic way. In this context, we present the rationale and design of an ongoing study aiming to assess the efficacy of PBMT on depressive symptoms and biomarkers associated with oxidative stress and mitochondrial function in adolescents with MDD.
... They are suitable for superficial tumor treatments and can be used in endoscopic and interstitial applications. LEDs are particularly useful in areas with limited access to advanced medical care due to their low cost and ease of use [51,[145][146][147][148]. ...
Oral cancers, specifically oral squamous cell carcinoma (OSCC), pose a significant global health challenge, with high incidence and mortality rates. Conventional treatments such as surgery, radiotherapy, and chemotherapy have limited effectiveness and can result in adverse reactions. However, as an alternative, photodynamic therapy (PDT) has emerged as a promising option for treating oral cancers. PDT involves using photosensitizing agents in conjunction with specific light to target and destroy cancer cells selectively. The photosensitizers accumulate in the cancer cells and generate reactive oxygen species (ROS) upon exposure to the activating light, leading to cellular damage and ultimately cell death. PDT offers several advantages, including its non-invasive nature, absence of known long-term side effects when administered correctly, and cost-effectiveness. It can be employed as a primary treatment for early-stage oral cancers or in combination with other therapies for more advanced cases. Nonetheless, it is important to note that PDT is most effective for superficial or localized cancers and may not be suitable for larger or deeply infiltrating tumors. Light sensitivity and temporary side effects may occur but can be managed with appropriate care. Ongoing research endeavors aim to expand the applications of PDT and develop novel photosensitizers to further enhance its efficacy in oral cancer treatment. This review aims to evaluate the effectiveness of PDT in treating oral cancers by analyzing a combination of preclinical and clinical studies.
Graphical Abstract
... Red and NIR wavelengths used in photobiomodulation (PBM) are well-documented in the literature for their anti-inflammatory and wound healing properties, with mechanisms involving cytochrome c oxidase [24]. It is also proposed that intra-mitochondrial NO is photodissociated by light, unclogging cytochrome c oxidase and enhancing ATP generation [25]. However, few studies have reported extracellular NO release using PBM. ...
Significance: This study investigates the therapeutic potential of photobiomodulation (PBM) using visible and
near-infrared (NIR) light on nitric oxide (NO) release from intact human skin. Given NO’s critical role in
physiological processes such as wound healing, inflammation control, and vasodilation, this research could lead
to innovative non-invasive treatments.
Aim: The primary aim was to explore how PBM at different wavelengths affects NO release from human skin.
Custom-built airtight sleeves equipped with gas ports were used to measure NO levels, assessing the impact of
three specific wavelengths of light (455 nm, 660 nm, and 850 nm).
Approach: Eighteen healthy participants had their forearms enclosed in airtight sleeves. The skin was irradiated
with the specified wavelengths at a fluence of 45 J/cm2 and an irradiance of 50 mW/cm2 for 15 min. NO
levels were quantified after irradiation using chemiluminescence detection (CLD), which measures the chemiluminescent
reaction of NO with ozone (O3) for real-time analysis.
Results: Significant differences in NO release were observed among the wavelengths tested, indicating that
PBM stimulates NO release from intact human skin.
Conclusions: The study provides strong evidence that PBM using visible and NIR light can enhance NO release
from human skin, suggesting potential therapeutic applications for conditions involving NO. Further research is
needed to understand the mechanisms behind PBM-induced NO release and its clinical implications.
... Several studies have explored the use of light-emitting diodes (LEDs) in dermatology [9] and their role as an activating light source for photosensitizers in photodynamic therapy, a non-invasive phototherapy based on a skincare treatment using varying wavelengths of light [10]. Photodynamic therapy for aesthetic dermatologic conditions has demonstrated some skin rejuvenating effects and does not cause burns compared to other anti-ageing treatments, such as chemical peels, dermabrasion, and laser therapy [11,12]. ...
Currently, the cosmetic industry is developing several treatments based on the use of lights with different wavelengths for anti-ageing strategies and facial rejuvenation. Some lights have been proven to be beneficial for our skincare, but their actual effects require an in-depth analysis. Ultra-weak photon emission (UPE) is a spontaneous, low intensity emission from all living systems produced as a consequence of metabolic reactions (e.g., oxidative metabolism, cell division, photosynthesis, or carcinogenesis). However, it can also be induced by several factors, such as light exposure, wounds, thermal shock, and other stress elements. Thus, measuring human biophotonic emission can open new horizons to explore the real benefits of light therapies, particularly regarding the direct relationship between light exposure and free radicals, such as reactive oxygen species (ROS), which are the main cause of UPE.
In this study, the ultra-weak photon emission from a sample of ten human beings after exposure to different lights was studied using red and green lights (artificially produced by an RGB LED lamp) and natural light (directly received from the sun), aiming to assess the UPE changes when directly focusing these types of lights on the skin. Hence, this technique could be proposed as a pioneering control tool in cosmetics, principally with phototherapies.
... New approaches have been tested and experimental studies have shown that antimicrobial blue light (ABL) therapy can be used as a treatment for VVC and RVVC [6][7][8]. ABL is a safe, painless technique and has super cial penetration into tissues (< 0.4 mm) [9]. In this way, ABL has the ability to inactivate microorganisms through the mechanism of pathogen-induced cell death. ...
... Our study showed that ABL is a well-tolerated and effective symptom treatment for women with RVVC until the 6-month follow-up. Pelvic pain was reported as an adverse event in two patients (3.2%) even though the depth of penetration of ABL into tissues is < 0.4 mm [9]. Thus, we believe that the pain could be due to a mechanical effect. ...
Objective
We conducted a prospective study with the objective of assessing the effects of antimicrobial blue light (ABL) therapy for recurrent vulvovaginal candidiasis (RVVC) in drug-resistant women.
Introduction
RVVC is defined as three or more episodes of candidiasis in a 12-month period. Conventional treatment is complex and often involves long-term or multiple treatments. ABL therapy is a promising treatment option as it is acceptable to women and has with few side effects.
Methods
Our study enrolled RVVC drug-resistant women, who received ABL through 10 sessions for 20 minutes once a week from January 2023 to January 2024. All women were followed up by 6 months after therapy.
Results
We included 62 patients. The overall positive response rates were 79% immediately after treatment and 58% after 6 months, respectively. There was an improvement in the symptoms of pruritus, burning, oedema, erythema and leucorrhoea.
Conclusion
ABL was an effective therapy to be employed in drug-resistant women suffering from RVVC.
... Studies show that it has anti-inflammatory action, activating cellular signaling pathways that modulate the function of skin cells, stimulating the production of fibroblasts, increasing tissue repair, and aiding wound healing through stimulation of oxidative phosphorylation. Therefore, we believe that red light can play an auxiliary role in the treatment of inflammatory acne [19,20]. ...
Aims: This study aims to assess the efficacy of red, blue, and combined red-blue light therapy versus 20% salicylic acid peel in treating Grades 2 and 3 inflammatory acne. Study Design: Cases studies. Place and Duration of Study: Universidade Nove de Julho, Universidade Adventista de São Paulo, São Paulo Brazil. Between March 2022 from April 2024. Introduction: Acne is an inflammatory disorder that occurs in the pilosebaceous follicles and deeply affects the self-esteem and quality of life of individuals. Conventional treatments usually produce side effects and promote antibiotic resistance. Light therapy has emerged as a promising modality in clinical and scientific realms for acne management. This study aims to evaluate the effectiveness of red, blue and combined red-blue light therapy versus 20% salicylic acid peeling in the treatment of inflammatory acne grade 2 and 3. Methodology: We divided 20 participants into four groups who used a mask of LEDs. Group 1 used a mask with blue light (470nm), group 2 used a mask with red light (660nm), group 3 used a mask with red (660nm) and blue (470nm) lights combined in the same device. The groups that used the LED masks received the treatment 3 times a week for 30 days, totaling 12 sessions. Group 4 was submitted to two sessions of salicylic acid peeling at 20%, every 15 days. Results: Blue light (group 1) showed an improvement of 28.40% in the general skin condition. Group 4 of salicylic acid peeling had an improvement of 28.37%. The combined red and blue light group had an improvement of 26.43%, while the red light showed an improvement of 10.97%. Conclusion: Based on the series of cases presented, all groups showed improvement, but blue light showed higher results than red light and salicylic acid. However, studies with a larger number of participants should be performed and the ideal parameters for Led use in inflammatory acne should be discussed.
