Monitoring perfusion and oxygen saturation in port-wine stains during vascular targeted photodynamic therapy

Devices and Methods for Dosimetry of Personalized Photodynamic Therapy of Tumors: A Review on Recent Trends

Significance: Despite the widespread use of photodynamic therapy in clinical practice, there is a lack of personalized methods for assessing the sufficiency of photodynamic exposure on tumors, depending on tissue parameters that change during light irradiation. This can lead to different treatment results. Aim: The objective of this article was to conduct a comprehensive review of devices and methods employed for the implicit dosimetric monitoring of personalized photodynamic therapy for tumors. Methods: The review included 88 peer-reviewed research articles published between January 2010 and April 2024 that employed implicit monitoring methods, such as fluorescence imaging and diffuse reflectance spectroscopy. Additionally, it encompassed computer modeling methods that are most often and successfully used in preclinical and clinical practice to predict treatment outcomes. The Internet search engine Google Scholar and the Scopus database were used to search the literature for relevant articles. Results: The review analyzed and compared the results of 88 peer-reviewed research articles presenting various methods of implicit dosimetry during photodynamic therapy. The most prominent wavelengths for PDT are in the visible and near-infrared spectral range such as 405, 630, 660, and 690 nm. Conclusions: The problem of developing an accurate, reliable, and easily implemented dosimetry method for photodynamic therapy remains a current problem, since determining the effective light dose for a specific tumor is a decisive factor in achieving a positive treatment outcome.

Non-invasive efficacy assessment of pulsed dye laser and photodynamic therapy for port-wine stain

Port wine stain (PWS) is a congenital vascular malformation that commonly occurs on the face and neck. Currently, the main treatments for port wine stain are pulsed dye laser (PDL) and photodynamic therapy (PDT). However, the efficacy evaluation of PWS mostly relies on the subjective judgement of clinicians, and it is difficult to accurately respond to many small changes after treatment. Therefore, some non-invasive and efficient efficacy assessment methods are also needed. With the continuous development of technology, there are currently many visualisation instruments to evaluate PWS, including dermoscopy, VISIA-CR™ system, reflectance confocal microscopy (RCM), high-frequency ultrasound (HFUS), optical coherence tomography (OCT), Photoacoustic imaging (PAI), laser speckle imaging (LSI) and laser Doppler imaging (LDI). Among them, there are simple and low-cost technologies such as dermoscopy and the VISIA-CR™ system, but they may not be able to observe the deeper structures of PWS. At this time, combining techniques such as HFUS and OCT to increase penetration depth is crucial to evaluate PWS. In the future, the combination of these different technologies could help overcome the limitations of a single technology. This article provides a systematic overview of non-invasive methods for evaluating treatment efficacy in port wine stains and summarises their advantages and disadvantages.

Salvianolic acid B as a potent nano-agent for enhanced ALA-PDT of oral cancer and leukoplakia cells

BACKGROUND

Photodynamic therapy (PDT) relies on the light activation of a photosensitizers to generate reactive oxygen species such as singlet oxygen, but its effect on cancer therapy is limited dramatically by hypoxia in the tumor microenvironment.

OBJECTIVES

To determine the potential of a nano-photosensitizer loaded salvianolic acid B (SalB) and 5-aminolevulinic acid (ALA) for enhancing the efficacy of PDT in oral squamous cell carcinoma Cal27 cells and leukoplakia Leuk1 cells.

RESULTS

Singlet oxygen sensor green (SOSG) assay showed that nano-SalB-ALA generated higher levels of singlet oxygen, compared to nano-SalB and nano-ALA. Cellular uptake assay showed that nano-SalB-ALA effectively absorbed by Leuk1 cells. Importantly, cell counting kit-8 and flow cytometry revealed that PDT with nano-SalB-ALA effectively inhibited the viability and induced the apoptosis of Cal27 and Leuk1 cells, respectively. Moreover, the tumor xenograft study revealed that PDT with nano-SalB-ALA had a stronger inhibitory effect on tumor growth of nude mice, compared to control groups.

CONCLUSIONS

The novel photosensitizer nano-SalB-ALA remarkably enhanced the efficacy of PDT by improving singlet oxygen production, inhibiting cell proliferation, promoting cell apoptosis, and suppressing tumor growth. These suggest PDT with nano-SalB-ALA could be a clinically significant and potent treatment for oral cancer and leukoplakia.

Versatile Peptide-Based Nanosystems for Photodynamic Therapy

Photodynamic therapy (PDT) has become an important therapeutic strategy because it is highly controllable, effective, and does not cause drug resistance. Moreover, precise delivery of photosensitizers to tumor lesions can greatly reduce the amount of drug administered and optimize therapeutic outcomes. As alternatives to protein antibodies, peptides have been applied as useful targeting ligands for targeted biomedical imaging, drug delivery and PDT. In addition, other functionalities of peptides such as stimuli responsiveness, self-assembly, and therapeutic activity can be integrated with photosensitizers to yield versatile peptide-based nanosystems for PDT. In this article, we start with a brief introduction to PDT and peptide-based nanosystems, followed by more detailed descriptions about the structure, property, and architecture of peptides as background information. Finally, the most recent advances in peptide-based nanosystems for PDT are emphasized and summarized according to the functionalities of peptide in the system to reveal the design and development principle in different therapeutic circumstances. We hope this review could provide useful insights and valuable reference for the development of peptide-based nanosystems for PDT.

Effect of Hemoporfin-mediated photodynamic therapy in the treatment of facial port-wine stains on intraocular pressure

BACKGROUND

Photodynamic therapy (PDT) is a potential treatment for port-wine stains (PWS), but its effects on intraocular pressure (IOP) have not been reported. This study evaluated the efficacy of PDT for facial PWS and analyzed the changes in IOP before and after treatment.

METHODS

Data from 32 patients with facial PWS who underwent single PDT treatment at our department were collected. The patients were divided into three groups based on the location of the PWS. Group A (15 cases) involved the eyelid of the eye being measured; Group B (10 cases) was located near the eyes but did not involve the measured eyelid; and Group C (7 cases) was situated on the face but not near the eyes. IOP measurements were taken before and after treatment, and the efficacy and changes in IOP were analyzed.

RESULTS

The overall efficacy rates of single PDT were 84.37 %, demonstrating superior efficacy for the pink type, age < 6 years, and skin lesions < 10 cm2 (P < 0.05). The higher IOP was observed on the side with eyelid involvement of PWS (P < 0.001). The IOP of the affected side in Group A decreased by 2.13 ± 2.10 mmHg on average after treatment, which was statistically significant compared with the other two groups (P<0.05).

CONCLUSIONS

Eyelid involvement in PWS increases the risk of elevated IOP. Hemoporfin-mediated PDT can reduce the IOP in patients with PWS involving the eyelid within a safe range. PDT for facial PWS is considered to be safe and effective.

Dual-function microneedle array for efficient photodynamic therapy with transdermal co-delivered light and photosensitizers

Photodynamic therapy (PDT), as a globally accepted method for treating different forms of skin or mucosal disorders, requires efficient co-delivery of photosensitizers and corresponding therapeutic light. The adverse effects of intravenous injection of photosensitizers have been reduced by the development of microneedle arrays for transdermal local photosensitizer delivery. However, the drawbacks of the only available therapeutic light delivery method at the moment, which is directly applying light to the skin surface, are yet to be improved. This study presents a new strategy in which therapeutic light and photosensitizer were transdermally co-delivered into local tissues. A flexible dual-function microneedle array (DfMNA) which contains 400 microneedles was developed. Each microneedle consists of a dissolvable needle tip (140 μm in height) for delivering the photosensitizer and a transparent needle body (660 μm in height) for guiding therapeutic light. Using port-wine stains, which is a frequently occurring skin disorder caused by vascular malformation, as a model disease, the effectiveness of DfMNA mediated PDT has been verified on mice. Compared with the standard operation procedure of clinical PDT, the DfMNA decreases the amount of photosensitizer from 300 μg to 0.5 μg and reduces therapeutic light irradiance from 100 mW cm^-2 to 60 mW cm^-2 while realizing better treatment effects. As a result, the skin damage and the burden on the metabolic system have been alleviated. The DfMNA has a remarkably reduced photosensitizer amount and, for the first time, realized transdermal delivery of therapeutic light for PDT, thus avoiding the disadvantages of existing PDT methodologies.

High speed photo-mediated ultrasound therapy integrated with OCTA

Photo-mediated Ultrasound Therapy (PUT), as a new anti-vascular technique, can promote cavitation activity to selectively destruct blood vessels with a significantly lower amount of energy when compared to energy level required by other laser and ultrasound treatment therapies individually. Here, we report the development of a high speed PUT system based on a 50-kHz pulsed laser to achieve faster treatment, decreasing the treatment time by a factor of 20. Furthermore, we integrated it with optical coherence tomography angiography (OCTA) for real time monitoring. The feasibility of the proposed OCTA-guided PUT was validated through in vivo rabbit experiments. The addition of OCTA to PUT allows for quantitative prescreening and real time monitoring of treatment response, thereby enabling implementation of individualized treatment strategies.