Laser ablation and topical drug delivery: a review of recent advances

Strategies to Improve the Transdermal Delivery of Poorly Water-Soluble Non-Steroidal Anti-Inflammatory Drugs

The transdermal delivery of non-steroidal anti-inflammatory drugs (NSAIDs) has the potential to overcome some of the major disadvantages relating to oral NSAID usage, such as gastrointestinal adverse events and compliance. However, the poor solubility of many of the newer NSAIDs creates challenges in incorporating the drugs into formulations suitable for application to skin and may limit transdermal permeation, particularly if the goal is therapeutic systemic drug concentrations. This review is an overview of the various strategies used to increase the solubility of poorly soluble NSAIDs and enhance their permeation through skin, such as the modification of the vehicle, the modification of or bypassing the barrier function of the skin, and using advanced nano-sized formulations. Furthermore, the simple yet highly versatile microemulsion system has been found to be a cost-effective and highly successful technology to deliver poorly water-soluble NSAIDs.

Carbon dots as a novel photosensitizer for photodynamic therapy of cancer and bacterial infectious diseases: recent advances

Carbon dots (CDs) are novel carbon-based nanomaterials that have been used as photosensitizer-mediated photodynamic therapy (PDT) in recent years due to their good photosensitizing activity. Photosensitizers (PSs) are main components of PDT that can produce large amounts of reactive oxygen species (ROS) when stimulated by light source, which have the advantages of low drug resistance and high therapeutic efficiency. CDs can generate ROS efficiently under irradiation and therefore have been extensively studied in disease local phototherapy. In tumor therapy, CDs can be used as PSs or PS carriers to participate in PDT and play an extremely important role. In bacterial infectious diseases, CDs exhibit high bactericidal activity as CDs are effective in disrupting bacterial cell membranes leading to bacterial death upon photoactivation. We focus on recent advances in the therapy of cancer and bacteria with CDs, and also briefly summarize the mechanisms and requirements for PSs in PDT of cancer, bacteria and other diseases. We also discuss the role CDs play in combination therapy and the potential for future applications against other pathogens.

Deep learning-assisted 3D laser steering using an optofluidic laser scanner

Laser ablation is an effective treatment modality. However, current laser scanners suffer from laser defocusing when scanning targets at different depths in a 3D surgical scene. This study proposes a deep learning-assisted 3D laser steering strategy for minimally invasive surgery that eliminates laser defocusing, increases working distance, and extends scanning range. An optofluidic laser scanner is developed to conduct 3D laser steering. The optofluidic laser scanner has no mechanical moving components, enabling miniature size, lightweight, and low driving voltage. A deep learning-based monocular depth estimation method provides real-time target depth estimation so that the focal length of the laser scanner can be adjusted for laser focusing. Simulations and experiments indicate that the proposed method can significantly increase the working distance and maintain laser focusing while performing 2D laser steering, demonstrating the potential for application in minimally invasive surgery.

Efficacy and Safety of Ablative Fractional Laser in Melasma: A Meta-analysis and Systematic Review

Melasma is a common acquired skin pigmentation disorder. The treatment is urgent but challenging. Ablative fractional laser (AFL) can improve pigmentation, but the efficacy and potential side effects are still debatable. This study aimed to evaluate the efficacy and safety of ablative fractional lasers in the treatment of melasma. A comprehensive systematic search of literature published before June 20, 2023, was conducted on online databases, including PubMed, Embase, Cochrane Library, and Web of Science. The data obtained were analyzed using Review Manager 5.4 software. Fourteen randomized controlled trials, comprising 527 patients, were included. Compared to the drug alone, the combination of AFL and the drug showed improved therapeutic efficacy in the melasma area and severity index (MASI) (MD = 1.54, 95% CI [0.16, 2.92], P = 0.03) and physician global assessment (RR = 1.61, 95% CI [1.08, 2.41], P = 0.02). However, no statistically significant results were found in patient self-assessment (RR = 1.56, 95% CI [0.88, 2.76], P = 0.12). As an individual therapy, AFL is not superior to any other lasers in terms of MASI (MD = 2.66, 95% CI [-1.32, 6.64], P = 0.19) or melanin index (MD = -7.06, 95% CI [-45.09, 30.97], P = 0.72). Common adverse events included transient erythema, burning, edema, and superficial crusting. Only a few patients experienced reversible post-inflammatory hyperpigmentation, herpes labialis, and acne breakouts. These results support the application of AFL as a viable treatment option for melasma, particularly in refractory and severe cases. Rational parameterization or combination therapy may lead to significant clinical improvement with fewer complications.

The quantitative analysis of low-concentration (2%) ALA-PDT assisted with Q-switch 1064-nm Nd:YAG laser for acne vulgaris treatment

Conventional 5-aminolevulinic acid-photodynamic (ALA-PDT) therapy (10-20%) has been widely applied for moderate-to-severe acne. The aim of this study is to investigate the effects of non-ablative Q-switched 1064-nm Nd:YAG laser-assisted ALA-PDT with low concentration (2%) on the treatment of acne vulgaris. Enrolled patients were randomly assigned to 2 groups. One group received combined therapy of 2% ALA-PDT and non-ablative Q-switched 1064-nm Nd:YAG laser, and the other received only 2% ALA-PDT. Patients in each group had received 3-session treatments with 4-week intervals (week 0, 4, and 8). Sebum secretion, melanin index, erythema index, and transepidermal water loss (TEWL) were assessed at week 2, 8, 12, and 24. VISIA® skin image system score and global esthetic improvement scale (GAIS) were also evaluated. Twenty-four participants were enrolled and evenly randomized to two groups. Significant improvement in sebum secretion was noted in combined therapy group compared to the monotherapy group at week 12 (37.5% versus 16.3%), and the improvement would still be noted until week 24 (18.3% versus 17.4%). Combined group also showed more severe melanin index and erythema index after treatment. For VISIA® skin analysis, patients in combined group had better percentile ranking in porphyrins and red-light images. There were no significant differences in GAIS at the end of the follow-up between each group, whereas higher proportion of satisfaction was noted in combined group at week 2. With the assistance of laser, low concentrations (2%) of 5-ALA can provide effective phototoxic reactions in treating acne vulgaris. The satisfaction of patients is high with acceptable adverse effects.

The Secretome of Irradiated Peripheral Mononuclear Cells Attenuates Hypertrophic Skin Scarring

Hypertrophic scars can cause pain, movement restrictions, and reduction in the quality of life. Despite numerous options to treat hypertrophic scarring, efficient therapies are still scarce, and cellular mechanisms are not well understood. Factors secreted by peripheral blood mononuclear cells (PBMCsec) have been previously described for their beneficial effects on tissue regeneration. In this study, we investigated the effects of PBMCsec on skin scarring in mouse models and human scar explant cultures at single-cell resolution (scRNAseq). Mouse wounds and scars, and human mature scars were treated with PBMCsec intradermally and topically. The topical and intradermal application of PBMCsec regulated the expression of various genes involved in pro-fibrotic processes and tissue remodeling. We identified elastin as a common linchpin of anti-fibrotic action in both mouse and human scars. In vitro, we found that PBMCsec prevents TGFβ-mediated myofibroblast differentiation and attenuates abundant elastin expression with non-canonical signaling inhibition. Furthermore, the TGFβ-induced breakdown of elastic fibers was strongly inhibited by the addition of PBMCsec. In conclusion, we conducted an extensive study with multiple experimental approaches and ample scRNAseq data demonstrating the anti-fibrotic effect of PBMCsec on cutaneous scars in mouse and human experimental settings. These findings point at PBMCsec as a novel therapeutic option to treat skin scarring.

Laser-Assisted Drug Delivery in the Treatment of Scars, Rhytids, and Melasma: A Comprehensive Review of the Literature

Although broad reviews on laser-assisted drug delivery (LADD) have been published in the past, an updated focused examination of its utility in the context of common, treatment-resistant, dermatologic conditions has not been published. This article reports a comprehensive scoping review of the potential benefits of LADD compared to laser or drug monotherapy for the treatment of 3 such conditions: scars, rhytids, and melasma. A PubMed (National Institutes of Health; Bethesda, MD) search was conducted for keywords including "laser-assisted drug delivery," "scar," "rhytid," and "melasma." Out-of-scope studies were excluded. To evaluate the efficacy of LADD for the treatment of scars, relevant articles were categorized by scar type: hypertrophic/keloid, atrophic, and hypopigmented. LADD, with both ablative and nonablative laser types, was studied in combination with corticosteroids, botulinum toxin-A (BTX-A), 5-fluorouracil, 5-aminolevulinic acid photodynamic therapy, stem cells, platelet-rich plasma, and prostaglandin analogs for the treatment of scars. Some randomized controlled trials demonstrated the efficacy of LADD, whereas others showed no significant differences in clinical outcomes but demonstrated reduced adverse effects. Regarding rhytids, laser treatment has been combined with various cosmeceuticals, including poly-L-lactic acid, topical retinaldehyde, and topical BTX-A. The studies reviewed supported the use of LADD with these drugs over monotherapy. Some studies showed that LADD was effective for the absorption of drugs such as poly-L-lactic acid and BTX-A which are often not effective topically. For melasma treatment, LADD with tranexamic acid and hydroquinone was superior in some studies, but not significantly different than monotherapy in other studies. LADD with certain drugs could be considered to treat scars, rhytids, and melasma.

LEVEL OF EVIDENCE: 5

Laser-assisted nanoparticle delivery to promote skin absorption and penetration depth of retinoic acid with the aim for treating photoaging

Retinoic acid (RA) is an approved treatment for skin photoaging induced by ultraviolet (UVA). Topically applied RA is mainly located in the stratum corneum (SC) with limited diffusion into the deeper strata. A delivery system capable of facilitating dermal delivery and cellular internalization for RA is critical for a successful photoaging therapy. Two delivery approaches, namely nanoparticles and laser ablation, were combined to improve RA's absorption efficacy and safety. The nanoparticle absorption enhancement by the lasers was compared between full-ablative (Er:YAG) and fractional (CO₂) modalities. We fabricated poly-L-lactic acid (PLA) and PLA/poly(lactic-co-glycolic acid) (PLGA) nanoparticles by an emulsion-solvent evaporation technique. The mean size of PLA and PLA/PLGA nanocarriers was 237 and 222 nm, respectively. The RA encapsulation percentage in both nanosystems was > 96 %. PLA and PLA/PLGA nanocarriers promoted RA skin deposition by 5- and 3-fold compared to free control. The ablative lasers further enhanced the skin deposition of RA-loaded nanoparticles, with the full-ablative laser showing greater permeation enhancement than the fractional mode. The skin biodistribution assay evaluated by confocal and fluorescence microscopies demonstrated that the laser-assisted nanoparticle delivery achieved a significant dermis and follicular accumulation. The cell-based study indicated a facile uptake of the nanoparticles into the human dermal fibroblasts. The nanoparticulate RA increased type I collagen and elastin production in the UVA-treated fibroblasts. A reduction of matrix metalloproteinase (MMP)-1 was also highlighted in the photoaging cells. The calculation of therapeutic index (TI) by multiplying collagen/elastin elevation percentage and skin deposition predicted better anti-photoaging performance in Er:YAG laser-assisted nanoparticle delivery than CO₂ laser. Nanoencapsulation of RA decreased the cytotoxicity against skin fibroblasts. In vivo skin tolerance test on a nude mouse showed less skin damage after topical application of the nanoparticles than free RA. Our results hypothesized that the laser-mediated nanoparticle delivery provided an efficient and safe use for treating photoaging.

Enhancing Skin Uptake of Topical Antioxidants With 1,440-nm Nonablative Fractional Diode Laser Pretreatment

BACKGROUND

Energy-based devices, such as nonablative lasers, are a promising method to enhance the delivery and absorption of topically applied molecules.

OBJECTIVE

To characterize ex vivo uptake of common antioxidant topicals after pretreatment with a nonablative laser wavelength.

MATERIALS AND METHODS

Using donor human skin tissue, uptake of 3 topical antioxidants was analyzed (C E Ferulic with 15% l-ascorbic acid [15% vitamin C serum], Phloretin CF with ferulic acid [10% vitamin C serum], and Phyto+ [botanical serum]; SkinCeuticals, Dallas, TX; 2010 formulations) after pretreatment with a 1,440-nm nonablative fractional diode laser.

RESULTS

Pretreatment with the 1,440-nm laser enhanced uptake of 15% and 10% vitamin C serums by approximately 10 and 21 times, respectively, compared to controls. Laser pretreatment also enhanced uptake of botanical serum by approximately 6 times relative to controls. Permeation of vitamin C and botanical serums was also enhanced through laser pretreatment.

CONCLUSION

Nonablative laser pretreatment increased uptake and permeation of topical antioxidants. Optimizing treatment requires consideration of the device and treatment parameters as well as the properties of the topical formulation.

Laser-assisted nanocarrier delivery to achieve cutaneous siRNA targeting for attenuating psoriasiform dermatitis

Psoriasis is an autoimmune skin disorder presenting the excessive expression of interleukin (IL)-6. The topical use of small interfering RNA (siRNA) has been increasingly discovered for treating skin diseases. A delivery system capable of protecting siRNA while facilitating both skin targeting and cellular entrance is critical for the successful medication of topically-applied siRNA. Herein, we developed a delivery system for siRNA based on poly(lactic-co-glycolic acid) (PLGA) nanoparticles and combined this system with an ablative laser to promote skin absorption for topical psoriasis therapy. The siRNA absorption enhancement was compared by two laser modalities: a fractional CO₂ laser and a fully-ablative Er:YAG laser. We characterized the effect of the delivery system by the cellular uptake, IL-6 silencing, in vitro skin absorption, cutaneous biodistribution, and in vivo psoriasiform dermatitis in mice. The nanocarriers showed minimal cytotoxicity and facile cellular uptake to knock down the IL-6 expression. The nanoformulation containing a cationic surfactant (Forestall) for ion pairing with siRNA achieved a 66% and 77% IL-6 knockdown efficiency toward keratinocytes and macrophages, respectively. In the Franz cell absorption, the lasers increased the naked siRNA penetration to the receptor compartment by 3.7-5.0-fold but remarkably reduced skin deposition using imiquimod (IMQ)-treated psoriasiform skin as the barrier. The fractional laser facilitated nanoparticle-associated siRNA skin deposition up to 3.3-fold, whereas the transport of the nanocarriers to the receptor was negligible. Qualitatively, the lasers increased nanoparticle delivery in the epidermis with limited effect to elevate the penetration depth. The fractional-mediated nanocarrier delivery dramatically attenuated the erythema and scaly lesions of psoriasiform dermatitis. The histological examination displayed a reduction of epidermal hyperplasia and macrophage infiltration by the combination of laser and nanosystem. The passive and laser-assisted naked siRNA delivery was less effective in mitigating dermatitis. The topical delivery of fractional laser-assisted nanoparticles on mice resulted in a 56% IL-6 knockdown. Our results manifested the benefit of cutaneous siRNA targeting using ablative lasers to deliver nanocarriers for treating psoriatic inflammation.

Evaluating the Efficacy of the Er,Cr:YSGG Fractional Laser Before Treatment With Triamcinolone NN Ointment in Oral Lichen Planus Lesions

Introduction: It has been demonstrated that laser technology can enhance topical drug absorption. This study aimed to determine the effects of Er,Cr:YSGG laser radiation before the application of topical corticosteroids in the healing of oral lichen planus. Methods: In this double-blind split-mouth clinical trial, 32 lesions were chosen from eight patients affected by oral lichen planus (OLP). The oral lesions were randomly categorized into two groups. The first group had topical treatment with triamcinolone NN ointment and the second group had laser radiation (Er,Cr:YSGG) for eight weeks before starting the ointment. For each lesion, the irritating level based on the VAS score, the lesion level based on the Thongprasom scale score, and the healing time were measured, and the collected data were analyzed by the Friedman test and the Wilcoxon’s statistical test. Results: The mean healing time based on the verbal analog scale (VAS) score was not significantly different between the two treatment groups (P>0.05). The mean healing time based on Thongprasom scale scores did not show any significant difference between the two treatment groups (P>0.05). Conclusion: The application of the Er,Cr:YSGG laser before treatment with triamcinolone NN ointment did not show any advantage for the average healing time compared to a medicine regimen with only triamcinolone NN ointment.

Cutaneous Delivery of Cosmeceutical Peptides Enhanced by Picosecond- and Nanosecond-Domain Nd:YAG Lasers with Quick Recovery of the Skin Barrier Function: Comparison with Microsecond-Domain Ablative Lasers

Picosecond or nanosecond-domain non-ablative lasers generate faster photothermal effects and cause less injury than microsecond lasers. In this study, we investigated the enhancing effect of 1064 nm picosecond- and nanosecond-domain neodymium (Nd):yttrium–aluminum–garnet (YAG) lasers on the cutaneous delivery of cosmeceutical peptides. Microsecond-domain fractional ablative CO2 and fully ablative erbium (Er):YAG lasers were also used for comparison. In the Franz diffusion cell study, pig or mouse skin was treated with a laser before exposure to palmitoyl tripeptide (PT)-1, PT-38, and copper tripeptide (CT)-1 at a concentration of 150 μM. Psoriasiform, atopic dermatitis (AD)-like, and photoaged skins were also developed as permeation barriers. The non-ablative laser elicited the ultrastructural disruption of the stratum corneum and epidermal vacuolation. All laser modalities significantly increased the skin permeation of peptides in vitro. The non-ablative laser chiefly enhanced peptide delivery to the receptor compartment, whereas the ablative laser mainly increased the intracutaneous peptide deposition. The picosecond- and nanosecond-domain Nd:YAG lasers elevated the amount of PT-1 in the receptor up to 40- and 22-fold compared with untreated skin, respectively. Laser treatment promoted peptide delivery in barrier-deficient and inflamed skins, although this enhancement effect was less than that observed in healthy skin. Fluorescence microscopy indicated the capability of the non-ablative laser to deliver peptides to deeper skin strata. The ablative laser confined the peptide distribution in the epidermis. Confocal microscopy showed that peptides penetrated the skin along the microdots created by the fractional Nd:YAG and CO2 lasers. The skin barrier function determined by transepidermal water loss suggested quick recovery when using a nanosecond-domain laser (within 4 h). A longer period was needed for the skin treated with the fully ablative Er:YAG laser (76–84 h). Nanosecond non-ablative laser-facilitated peptide delivery may become an efficient and safe approach for cosmeceutical applications.

Laser-Assisted Hyaluronic Acid Delivery by Fractional Carbon Dioxide Laser in Facial Skin Remodeling: A Prospective Randomized Split-Face Study in France

BACKGROUND AND OBJECTIVES

Combining the efficacy of ablative fractional carbon dioxide lasers (AFXL) to laser-assisted hyaluronic acid delivery (LAHAD) has not yet been studied. The objective of our study was to evaluate the safety and the efficacy of laser-assisted hyaluronic acid (HA) delivery with AFXL in facial skin remodeling.

STUDY DESIGN/MATERIALS AND METHODS

We conducted a prospective, double-blinded, randomized split-face study on 20 patients from 30 to 70 years old, with a skin phototype from I to IV. Each patient received full-face treatment with AFXL, immediately followed by the application in droplets into the fractional ablative tunnels of 1 ml of HA gel on one hemiface and 1 ml of physiological saline on the other hemiface. To evaluate postlaser aftermath, the intensity of erythema, edema, and crusts was graded. To assess facial skin remodeling, we scored the improvement of skin texture, firmness, fine lines, and skin radiance from baseline. Patients were evaluated on the 3rd and 7th day, 1st and 3rd month using clinical evaluations, photographs, and patient questionnaires.

RESULTS

We showed equivalence in postlaser aftermath between HA-treated and nontreated hemiface. Trend data analyses at the 3rd month suggested that immediate application of HA after AFXL resulted in a greater improvement in facial skin remodeling, especially for skin texture (mean score of 2.60 vs. 2.45) and skin firmness (mean score of 2.55 vs. 2.40). Skin radiance showed the best improvement, reaching almost a score of 5/10.

CONCLUSIONS

LAHAD with AFXL is a safe treatment showing promising results in facial skin remodeling. These findings need to be confirmed by a larger study to evaluate the value of LAHAD in daily clinical practice. Lasers Surg. Med. © 2021 Wiley Periodicals LLC.

Low-fluence laser-facilitated platelet-rich plasma permeation for treating MRSA-infected wound and photoaging of the skin

Platelet-rich plasma (PRP) is rich in cytokines and growth factors and is a novel approach for tissue regeneration. It can be used for skin rejuvenation but the large molecular size of the actives limits its topical application. In this study, low-fluence laser-facilitated PRP was delivered to evaluate its effect on absorption through the skin, infection-induced wound, and photoaging. The PRP permeation enhancement was compared for two ablative lasers: fractional (CO₂) laser and fully-ablative (Er:YAG) laser. In the Franz cell experiment, pig skin was treated with lasers with superficial ablation followed by the application of recombinant cytokines, growth factors, or PRP. The transport of interferon (IFN)-γ and tumor necrosis factor (TNF)-α was negligible in intact skin and stratum corneum (SC)-stripped skin. Both lasers significantly elevated skin deposition of IFN-γ and TNF-α from PRP, and fully-ablative laser showed a higher penetration enhancement. A similar tendency was found for vascular endothelial growth factor and epidermal growth factor. Er:YAG laser-exposed skin displayed 1.8- and 3.9-fold higher skin deposition of platelet-derived growth factor (PDGF)-BB and transforming growth factor (TGF)-β1 from PRP, respectively. According to the confocal images, both laser interventions led to an extensive and deep distribution of IFN-γ and PDGF-BB in the skin. In the in vivo methicillin-resistant Staphylococcus aureus (MRSA) infection model, CO₂ laser- and Er:YAG laser-assisted PRP delivery reduced bacterial load from 1.8 × 10⁶ to 5.9 × 10⁵ and 1.4 × 10⁴ colony-forming units, respectively. The open wound induced by MRSA was closed by the laser-assisted PRP penetration. In the mouse photoaging model, elastin and collagen deposition were fully restored by combined PRP and full-ablative laser but not by PRP alone and PRP combined with fractional laser. Laser-facilitated PRP delivery even with a low fluence setting can be considered a promising strategy for treating some dermatological disorders.

The Evolving Story of Laser Therapeutics for Basal Cell Carcinoma

BACKGROUND

The increasing burden from basal cell carcinoma (BCC) has stimulated the development of alternative treatments for these tumors.

OBJECTIVE

This review focuses on upcoming laser treatments for BCC and highlights the limitations of these therapies.

METHODS

A PUBMED search was conducted for articles on laser therapy of BCC. Key studies involving lasers to treat BCC were reviewed. Novel approaches to BCC are also described.

RESULTS

Vascular-specific laser therapy has increasingly been studied as an addition in the therapeutic armamentarium of BCC. Although these studies demonstrate efficacy for nonaggressive BCC, optimization of this technique is ongoing to minimize scarring. A more targeted approach to the treatment of BCC, such as immunized photothermal therapy or laser-assisted chemotherapeutic delivery, may result in less scarring, while maintaining efficacy similar to that of lasers targeting tumor vasculature.

CONCLUSION

Vascular-specific laser therapies show promise in treating low-risk BCC; however, scarring is not an uncommon adverse event. Although only animal studies have been performed to date, laser-activated gold nanoparticle therapy and laser-assisted drug delivery of vismodegib are potential therapies that theoretically confer a more selective approach. Laser modalities demonstrate promise in the treatment of nonaggressive BCC, although long-term studies have yet to be published.

Treatment of Psoriasis: Novel Approaches to Topical Delivery

Topical treatment is the cornerstone for the management of mild to moderate psoriasis. Despite efforts in drug development, patient's satisfaction with the available topical treatments is limited. A strategy to improve safety, efficacy and comfort of topical treatment provides the development of new drug delivery and drug carrier systems. This review provides an overview of recent advances in this field with a focus on psoriasis. Laser-assisted drug delivery, foam formulations, nanoparticles, ethosomes, and niomes are considered. Hopefully, these new developments will improve topical drug therapy and patient satisfaction.