Effect of 630-NM pulsed laser irradiation on the proliferation of HeLa cells in Photofrin(®)-mediated photodynamic therapy

Photodynamic therapy: An emerging therapeutic modality in dentistry

Photodynamic Therapy (PDT) is a rapidly evolving, non-invasive treatment modality with considerable promise in dental pharmacotherapeutics. This review article comprehensively examines PDT, beginning with its principles and then delving into its diverse applications in dentistry, including periodontal disease, endodontics, oral cancer, dental implants, and dental caries. Each area presents the latest research and discusses the potential benefits and challenges. The unique advantages of PDT are highlighted, such as selective targeting, broad-spectrum antimicrobial effect, lack of resistance development, and its synergistic effect with other treatments. However, challenges such as photosensitizer delivery, light penetration, oxygen availability, and the need to standardize protocols are also acknowledged. The review further explores future perspectives of PDT in dentistry, including advancements in photosensitizer design, overcoming hypoxic limitations, personalized protocols, integration with other therapies, and standardization and regulation. The potential of advanced technologies, such as nanotechnology and synthetic biology, to improve PDT outcomes is also discussed. The review concludes that while PDT has shown immense potential to revolutionize dental pharmacotherapeutics, further high-quality research is needed to translate this potential into everyday dental practice. The promising future of PDT in dentistry suggests a more effective and less invasive treatment option for a range of dental conditions.

Microfluidic system with light intensity filters facilitating the application of photodynamic therapy for high-throughput drug screening

BACKGROUND

Photodynamic therapy utilizes light energy with a photosensitizer (a light-sensitive drug) to kill cancer cells through light activation. When a photosensitizer is injected into the bloodstream and exposed to a specific wavelength of light, it generates oxygen to destroy or damage nearby cancer cells, while minimizing side effects on normal cells. Although photodynamic therapy is effective for treating cancer, various parameters, such as the optimum light intensity and photosensitizer dose, are currently poorly understood due to the complexity of conventional experimental schemes.

METHODS

To effectively perform a simultaneous single parallel test for several different light irradiation conditions on each cell, a microfluidic device was developed to generate eight different intensities from a single light-emitting diode source, through eight different color dye concentrations functioning as light intensity filters. To show that this novel high-throughput microfluidic system can analyze the effects of various light intensities during photodynamic therapy, the optimum light intensities and photosensitizer doses were determined for two different cancer cell lines.

RESULTS

Optimum light intensities and photosensitizer were determined for all cell lines. The photodynamic therapy effects in response to different irradiated light intensities were characterized by analyzing cell viability after photosensitizer treatment CONCLUSIONS: : The developed platform is capable of being used as a photodynamic therapy screening tool. The proposed platform provides a simple and robust way to optimize the combined parameters of light intensity and dosage for diverse types of cancer cells.

In-Vitro Co-delivery of Decarbazine and Photosense using Poly lactic-co-glycolic acid nanocarrier for combinational therapy

PLGA (Poly lactic-co-glycolic acid) nanoparticles are in new trend for drug delivery due to their good biodegradability properties. In this study, we have synthesized the PLGA nanoparticles by solvent evaporation method and loaded the decarbazine (DTIC, 5-3,3-(dimethyl-ltriazeno)imidazole-4-carboxamide) and photosense (AlPc4) drug alone as well as combined with two different concentrations i-e 25 nM and 250 nM. No cytotoxicity (viability ∼ 100 %) was observed for different treatment arms either alone or in co-delivery of nano-formulation for Rhabdomyosarcoma (RD) cell culture which showed the biocompatibility of carrier. On comparison, the Photodynamic therapy (PDT) alone showed more significant cell death then the combinational therapy (PDT + chemotherapy) at 2 joule /cm² and 5 joule /cm². Lower doses co-delivery showed light dose dependent toxicity to culture i.e., 0 % death @ 2 joule /cm², ∼ 40 % death @ 5 joule /cm². Gene expressions of four apoptosis related genes (CASP3, CASP9, PARP1 and P53) were quantified by RT-PCR which shows down regulation for all the treatment arms indicating the absence of apoptosis for the cell death during PDT and combinational therapy. It was concluded that apoptosis related genes were down-regulated and morphological changes i.e., swelling and disruption suggest that the mode of cell death was necrosis.

Activatable photodynamic destruction of cancer cells by NIR dye/photosensitizer loaded liposomes

The phototoxicity of Chlorin e6 (Ce6) for photodynamic therapy (PDT) was found to be effectively suppressed by indocyanine green (ICG), a near infrared (NIR) dye.