Clinical Trials and Basic Research in Photodynamic Diagnostics and Therapies from the Center for Laser Diagnostics and Therapy in Poland

Evaluation of the Disinfection Efficacy of Er-YAG Laser Light on Single-Species Candida Biofilms: Systematic Review

The relevance of the current study is to increase the resistance of fungal biofilms to traditional disinfection methods. The aim of the study was to determine how effectively Er:YAG laser light inhibits single-species Candida biofilms. The study involved a systematic review of 57 scientific publications (2015-2024) selected according to specific criteria, followed by an assessment of quantitative and qualitative indicators of colony-forming unit reduction. The results show that under optimal parameters (power 1.5-3.9 W and duration 60-90 s), the Er:YAG laser can reduce the number of viable Candida albicans cells by an average of 70-90%, and when combined with sodium hypochlorite or chlorhexidine solutions, this figure can exceed 90%. Separate in vitro tests show that Candida glabrata and Candida tropicalis require higher power or longer exposure to achieve a similar effect, while the use of the Er:YAG laser on titanium and dental surfaces minimizes damage to the substrate and effectively removes the biofilm matrix. In addition, laser treatment accelerates tissue regeneration and helps reduce the number of cases of reinfection, which is confirmed by the positive dynamics in clinical practice. Data analysis using confocal microscopy and microbiological seeding indicates a significant disruption of the biofilm structure and increased permeability to antimycotics after laser exposure. Er:YAG laser disinfection method is promising in counteracting fungal biofilms, especially for surfaces with a high risk of microbial colonization. The practical value lies in the possibility of developing standard protocols for the clinical use of the laser, which will increase the effectiveness of treatment and prevention of Candidal lesions.

Applications and challenges of photodynamic therapy in the treatment of skin malignancies

Photodynamic Therapy (PDT), as a minimally invasive treatment method, has demonstrated its distinct advantages in the management of skin malignant tumors. This article examines the current application status of PDT, assesses its successful cases and challenges in clinical treatment, and anticipates its future development trends. PDT utilizes photosensitizers to interact with light of specific wavelengths to generate reactive oxygen species that selectively eradicate cancer cells. Despite PDT's exceptional performance in enhancing patients' quality of life and prognosis, the limitation of treatment depth and the side effects of photosensitizers remain unresolved issues. With the advancement of novel photosensitizers and innovative treatment technology, the application prospects of PDT are increasingly expansive. This article delves into the mechanism of PDT, its application in various skin malignancies, its advantages and limitations, and envisions its future development. We believe that through continuous technological enhancements and integration with other treatment technologies, PDT has the potential to assume a more pivotal role in the treatment of skin malignancies.

Advances in Medicine: Photodynamic Therapy

Over the past decades, medicine has made enormous progress, revolutionized by modern technologies and innovative therapeutic approaches. One of the most exciting branches of these developments is photodynamic therapy (PDT). Using a combination of light of a specific wavelength and specially designed photosensitizing substances, PDT offers new perspectives in the fight against cancer, bacterial infections, and other diseases that are resistant to traditional treatment methods. In today's world, where there is a growing problem of drug resistance, the search for alternative therapies is becoming more and more urgent. Imagine that we could destroy cancer cells or bacteria using light, without the need to use strong chemicals or antibiotics. This is what PDT promises. By activating photosensitizers using appropriately adjusted light, this therapy can induce the death of cancer or bacterial cells while minimizing damage to surrounding healthy tissues. In this work, we will explore this fascinating method, discovering its mechanisms of action, clinical applications, and development prospects. We will also analyze the latest research and patient testimonies to understand the potential of PDT for the future of medicine.

Synergistic antimicrobial photodynamic therapy using gated mesoporous silica nanoparticles containing curcumin and polymyxin B

Photodynamic Therapy is a therapy based on combining a non-toxic compound, known as photosensitizer (PS), and irradiation with light of the appropriate wavelength to excite the PS molecule. The photon absorption by the PS leads to reactive oxygen species generation and a subsequent oxidative burst that causes cell damage and death. In this work, we report an antimicrobial nanodevice that uses the activity of curcumin (Cur) as a PS for antimicrobial Photodynamic Therapy (aPDT), based on mesoporous silica nanoparticles in which the action of the classical antibiotic PMB is synergistically combined with the aPDT properties of curcumin to combat bacteria. The synergistic effect of the designed gated device in combination with irradiation with blue LED light (470 nm) is evaluated against Escherichia coli, Pseudomonas aeruginosa and Staphylococcus epidermidis. The results show that the nanodevice exhibits a noteworthy antibacterial activity against these microorganisms, a much more significant effect than free Cur and PMB at equivalent concentrations. Thus, 0.1 µg/mL of MSNs-Cur-PMB eliminates a bacterial concentration of about 105 CFU/mL of E. coli, while 1 µg/mL of MSNs-Cur-PMB is required for P. aeruginosa and S. epidermidis. In addition, antibiofilm activity against the selected bacteria was also tested. We found that 0.1 mg/mL of MSNs-Cur-PMB inhibited 99 % biofilm formation for E. coli, and 1 mg/mL of MSNs-Cur-PMB achieved 90 % and 100 % inhibition of biofilm formation for S. epidermidis and P. aeruginosa, respectively.

Fluorescence spectral analysis and logistic regression modeling for diagnosing basal cell carcinoma on head and neck

The optical fluorescence method is distinguished by key features such as non-invasiveness, high sensitivity, and resolution, which are superior to traditional diagnostic approaches. Unlike histopathological examinations and biochemical analyses, optical diagnostic methods obviate the need for tissue sampling, enabling the analysis of virtually unlimited material. The research aims to examine the effectiveness of emission spectra analysis in the diagnosis of basal cell carcinoma (BCC) of the scalp and neck. The analysis was based on data provided by Specialized Hospital No. 2 in Bytom comprising a study sample of 10 patients. For each patient, fluorescence emission spectra were recorded from each of 512 points along a 5 mm line. The results obtained from the histopathological examination, the analysis and morphological evaluation of the tissue, and the diagnosis through microscopic observation were used to define a dichotomous variable (presence or absence of a cancerous lesion), adopted in the study as the modeled variable. The next step of the presented study involved constructing a logistic regression model for identifying cancerous lesions depending on the biochemical indicator's relative fluorescence value (RFV) and emission wavelength (ELW) within the 620 nm to 730 nm range. This wavelength range is often used in fluorescence diagnostics to detect various pathologies, including cancerous lesions. The resulting binary logistic regression model, logit(p)=-33.17+0.04ELW+0.01RFV, indicates a statistically significant relationship between wavelength and relative fluorescence values with the probability of detecting cancer. The estimated model exhibits a good fit and high predictive accuracy. The overall model accuracy is 84.8 %, with the correct classification rates at approximately 96 % for healthy individuals and 74 % for individuals with cancer. These findings underscore the potential of photodynamic diagnostics in cancer detection and monitoring.

Photodynamic inactivation of Streptococcus pneumoniae with external illumination at 808 nm through the ex vivo porcine thoracic cage

Pneumonia is responsible for high mortality rates around the world, and its major treatment is based on antibiotic treatment. Antimicrobial resistance has been increasing in the last years, resulting in relevant public health concern. A promising alternative for pneumonia is antimicrobial photodynamic therapy. The purpose of this study was to investigate whether 808 nm wavelength is able to be transmitted through the biological tissues of the thoracic wall and be delivered in enough energy inside the cage to activate indocyanine green and promote photodynamic response. A light source panel was developed composed of 200 lasers centered at 808 nm with an irradiance of 77.8 ± 10.0 mW/cm² and tested in an ex vivo thoracic cage model. Monte Carlo simulations were used to understand the photon migration through all the tissues at the thoracic wall. It was observed that tissues responsible for the major absorption of photons are the skin and subcutaneous fat. Experimental measurement of the irradiance was obtained after the light pass-through ex vivo pig thoracic cage, obtaining 3% to 5% of the emitted irradiance. Finally, it was observed that even with 3% of the initial irradiance, a 99.9% reduction of the Streptococcus pneumoniae was successfully achieved after 42.6 minutes of irradiation.

Targeted Nanoparticle Photodynamic Diagnosis and Therapy of Colorectal Cancer

Colorectal cancer (CRC) is an aggressive cancer that remains a challenge to diagnose and treat. Photodynamic diagnosis (PDD) and therapy (PDT) are novel alternative techniques, which can enhance early diagnosis, as well as elicit tumor cell death. This is accomplished through photosensitizer (PS) mediated fluorescence and cytotoxic reactive oxygen species activation upon laser light irradiation excitation at specific low and high range wavelengths, respectively. However, the lack of PS target tumor tissue specificity often hampers these techniques. This study successfully fabricated a bioactive nanoconjugate, ZnPcS4-AuNP-S-PEG5000-NH2-Anti-GCC mAb (BNC), based upon a polyethylene glycol-gold nanoparticle, which was multi-functionalized with a fluorescent PDT metalated zinc phthalocyanine PS, and specific anti-GCC targeting antibodies, to overcome CRC PDD and PDT challenges. The BNC was found to be stable and showed selectively improved subcellular accumulation within targeted CRC for improved PDD and PDT outcomes in comparison to healthy in vitro cultured cells. Additionally, the BNC reported significantly higher late apoptotic PDT-induced CRC cell death rates (34% ***) when compared to PDT PS administration alone (15% *). These results indicated that the improved PDD and PDT outcomes were due to the specific PS accumulation in CRC cells through nanoparticle carriage and bioactive anti-GCC targeting.

Photodynamic Therapy for the Treatment of Infected Leg Ulcers-A Pilot Study

Chronic and infected leg ulcers (LUs) are painful, debilitating, resistant to antibiotics, and immensely reduce a patient’s quality of life. The purpose of our study was to demonstrate the efficacy of photodynamic therapy (PDT) for the treatment of infected chronic LUs. Patients were randomized into two experimental groups: the first group received 5-aminolevulinic acid photodynamic therapy (ALA-PDT) (10 patients), and the second group of 10 patients received local octenidine dihydrochloride (Octenilin gel) exposed to a placebo light source with an inserted filter that mimiced red light. In the PDT group, we used 20% ALA topically applied for 4 hrs and irradiation from a Diomed laser source with a wavelength of 630 nm at a fluency of 80 J/cm². ALA-PDT was performed 10 times during a 14-day hospitalization in 10 patients of both sexes aged 40–85 years with chronic leg ulcers. Treatments were carried out at 3-week intervals for 3–5 cycles. At 8-month follow-up with the PDT group, complete remission (CR) was obtained in four patients (40%), partial response (>50% reduction in ulcer diameter) in four patients (40%), and no response in two patients (20%) who additionally developed deterioration of the local condition with swelling, erythema, and inflammation. To assess the degree of pain during the trials, we used a numeric rating scale (NRS). From the preliminary results obtained, we concluded that PDT can be used to treat leg ulcers as a minimally invasive and effective method with no serious side effects, although further studies on a larger group of patients with LUs are warranted.

An update in clinical utilization of photodynamic therapy for lung cancer

Lung cancer is one of the leading causes of cancer-related death worldwide, with nearly 1.8 million-diagnosis and 1.59 million deaths. Surgery, radiotherapy, and chemotherapy in individual or combination are commonly used to treat lung cancers. Photodynamic therapy (PDT) is a highly selective method for the destruction of cancer cells by exerting cytotoxic activity on malignant cells. PDT has been the subject of numerous clinical studies and has proven to be an effective strategy for cancer therapy. Clinical studies revealed that PDT could prolong survival in patients with inoperable cancers and significantly improve quality of life. For inoperable lung cancer cases, PDT could be an effective therapy. Despite the clinical success reported, PDT is still currently underutilized to treat lung cancer and other tumors. PTD is still a new treatment approach for lung cancer mainly due to the lack of enough clinical research evaluating its' effectiveness and side effects. In this review, we discuss the current prospects and future potentials of PDT in lung cancer treatment.

Alternative methods of photodynamic therapy and oxygen consumption measurements-A review

Photooxidation generates reactive oxygen species (ROS) through the interaction of dyes or surfaces with light radiation of appropriate wavelength. The reaction is of wide utility and is highly effective in photodynamic therapy (PDT) of various types of cancer and skin disease. Understanding generation of singlet oxygen has contributed to the development of PDT and its subsequent use in vivo. However, this therapy has some limitations that prevent its use in the treatment of cancers located deep within the body. The limited depth of light penetration through biological tissue limits initiation of PDT action in deep tissue. Measurement of oxygen photo consumption is critical due to tumor hypoxia, and use of magnetic resonance imaging (MRI) is particularly attractive since it is non-invasive. This article presents bioluminescence (BL) and chemiluminescence (CL) phenomena based on publications from the last 20 years, and preliminary results from our lab in the use of MRI to measure oxygen concentration in water. Current work is aimed at improving the effectiveness of singlet oxygen delivery to deep tissue cancer.