Assessment of ALA‐induced PpIX production in porcine skin pretreated with microneedles

Self Cite

Photodynamic Inactivation (PDI) is based on the use of a photosensitizer (PS) and light that results mainly in the production of reactive oxygen species, aiming to produce microorganism cell death. PS incubation time and light dose are key protocol parameters that influence PDI response; the correct choice of them can increase the efficiency of inactivation. The results of this study show that a minor change in the PDI protocol, namely light-driven incubation leads to a higher photosensitizer and more uniform cell uptake inside the irradiated zone. Furthermore, as the uptake increases, the damage caused by PDI also increases. The proposed light-driven incubation prior to the inactivation illumination dose has advantages when compared to the traditional PDI treatments since it can be more selective and effective. Using a violet light as pre-illumination (light-driven incubation) source and a red-light system as PDI source, it was possible to demonstrate that when compared to the traditional protocol of dark incubation, the pre-illuminated cell culture showed an inactivation increase of 7 log units. These in vitro results performed in Candida albicans cells may result in the introduction of a new protocol for PDI.

Section: Discussionmentioning

confidence: 99%

Light‐driven photosensitizer uptake increases Candida albicans photodynamic inactivation

Romano

Pratavieira

Silva

et al. 2017

Self Cite

“…PDT with 5‐aminolevulinic acid (ALA) is known to be limited for applications in tumors of large volume mainly due to the limited penetration of topical photosensitization. The kinetics and homogeneity of production of ALA‐induced Protoporphyrin (Pp) IX after the skin pre‐treatment with microneedles rollers of 0.5 mm, 1.0 mm and 1.5 mm length were investigated . An improvement in homogeneity and production of PpIX was shown in a porcine model.…”

Section: Photothermal and Photodynamic Therapymentioning

confidence: 99%

Modern trends in biophotonics for clinical diagnosis and therapy to solve unmet clinical needs

Krafft

2016

This contribution covers recent original research papers in the biophotonics field. The content is organized into main techniques such as multiphoton microscopy, Raman spectroscopy, infrared spectroscopy, optical coherence tomography and photoacoustic tomography, and their applications in the context of fluid, cell, tissue and skin diagnostics. Special attention is paid to vascular and blood flow diagnostics, photothermal and photodynamic therapy, tissue therapy, cell characterization, and biosensors for biomarker detection.

“…Topical PDT employing ALA and MAL has been widely accepted as an effective treatment for actinic keratosis (AK), superficial BCC (sBCC) and Bowen's disease (BD) . However, it is not recommended to treat SCC with deepest neoplastic invasion, in which the lower cream penetration is a limiting factor for the therapeutic effect promoted by PDT .…”

Section: Introductionmentioning

confidence: 99%

Optimization and therapeutic effects of PDT mediated by ALA and MAL in the treatment of cutaneous malignant lesions: A comparative study

Lima

Goulart

Bechara

et al. 2016

5-aminolevulinic acid (ALA) and its methylated ester (MAL) are the most common topical agents used in photodynamic therapy (PDT) as precursors of the photosensitizer protoporphyrin IX (PpIX). The induction of newly PpIX depends on incubation time of each photosensitizer in the tissue and the presence of high intralesional porphyrin levels is an important parameter for the PDT effectiveness. This study used laser-induced fluorescence (LIF) spectroscopy to evaluate the optimum time to light exposure of PDT mediated by ALA (20% w/w) and MAL (10% w/w) to treat malignant lesions precursors of cutaneous squamous cell carcinoma induced in mice. The therapeutic effects obtained by optimized ALA- and MAL-PDT were assessed 10 and 20 days after treatments. Higher PpIX levels were evidenced in the lesions photosensitized by ALA than MAL and according to LIF measurements the PDT irradiation was performed, respectively, at 300 and 330 minutes after ALA and MAL incubation. Histopathological analysis evidenced necrosis and epithelial atrophy after 10 days of PDT using both prodrugs, as well as reepitelization and collagen deposition at 20 days. Thus, despite the distinct concentration of ALA and MAL used in the formulation of each photosensitizing cream, PDT mediated by both photosensitizing agents obtained similar therapeutic outcomes.