Photodynamic Reaction Research Articles

Oxidovanadium(V) complexes as promising anticancer photosensitizers

Photodynamic therapy (PDT) is an alternative treatment widely used against cancer. PDT requires molecular systems, known as photosensitizers (PS), which not only exhibit strong absorption at a particular wavelength range, but also need to be selectively accumulated inside cancer cells. PS are activated by specific wavelengths that cause tumor cell death by mechanisms related with oxidative stress. In this paper, three oxidovanadium(V) complexes linked to a Schiff base, which exhibit anticancer activity by displaying desirable accumulation inside malignant cells, are studied using Density Functional Theory (DFT) and Time Dependent-DFT (TD-DFT) methodologies to characterize their structural and photophysical properties as possible PS. The maximum absorption of these complexes in aqueous solution was predicted to be approximately 460 nm presenting a ligand-to-metal charge transfer. Additionally, we describe the photodynamic type reaction that these complexes can undergo when considered as PS candidates. Our results suggest that the system, containing triethylammonium as substituent, is the most suitable complex to act both as PS and as a possible therapeutic candidate in PDT.

Impact of thiosemicarbazones on the accumulation of PpIX and the expression of the associated genes

Thiosemicarbazone derivatives are known for their broad biological activity including their antitumor potency. The aim of the current study was to examine the effect of a novel series of non-toxic iron chelators on the accumulation of protoporphyrin IX after external 5-aminolevulonic acid administration. From this series we selected one the most promising derivative which causes a pronounced increase in the concentration of protoporphyrin IX. The increase of the photosensitizer concentration is necessary for the trigger the efficient therapeutic effect of the photodynamic reaction. For selected compound 2 we performed an examination of a panel of the genes that are involved in the heme biosynthesis and degradation. Results indicated the crucial roles of ferrochelatase and heme oxygenase in the described processes. Surprisingly, there was a strict dependence on the type of the tested cell line. A decrease in the expression of the two aforementioned enzymes after incubation with compound 2 and 5-aminolevulonic acid is a commonly known fact and we detected this trend for the MCF-7 and HCT 116 cell lines. However, we noticed the upregulation of the tested targets for the Hs683 cells. These unconventional results prompted us to do a more in-depth analysis of the described processes. In conclusion, we found that compound 2 is a novel, highly effective booster of photodynamic therapy that has prospective applications.

Impact of Chlorophyllin Dye on some Enzyme Systems of the Cotton Leafworm, Spodoptera littoralis (Boisd.)

The second larval instarof the cotton leafworm, Spodoptera littoralis (Boisd.) as a series polyphagous pest was treated, in laboratory, by ingestion of two chlorophyll derivatives namly copper chlorophyllin (Chl-Cu) and magnesium chlorophyllin (Chl-Mg) to study the possible role of mixed function oxidases (MFO) in detoxifying the dye, and determine the efficancy of treatment on protein metabolizing enzymes or transaminases. Moreover, to clarify whether the photoactive dyes have non phototoxic effect. The larvae were treated for 24 hrs with LC50 of the dye followed by exposure to direct sunlight for 2 hr. Copper chlorophyllin was more potent than magnesium chlorophyllin and represented by LC50 = 0.130M and LC50 =0.299 M, respectively. The percentage mortility of larvae treated by LC50 of the dyes and kept in dark during the experimental time was up to 9%. The dark process appear to be less active than the light induced photo dynamic reactions. Biochemical analyses revealed that treatment led to induction of MFO system. It was 733, 926 and 687 μ mole substrate oxidized /min/g. b. wt for Chl-Mg, Chl-Cu and control, respectively. Effect of treatment on transaminases showed that GPT activity was significantly changed by both chlorophyll derivatives, while GOT activity was non significantly changed. Induced GPT level could be considered as a sing or secondary effect of chlorophyllin poisoning. This effect has been interprreted as suggestive of interinsic capacity of insect to repair damage. MFO might share in detoxifying chlorophyllins, and development of resistance to photodynamic pesticides. The observed dark effect suggests that the used photosynthetizers posses low interinsic chemical toxicity.

Folate-directed zinc (II) phthalocyanine loaded polymeric micelles engineered to generate reactive oxygen species for efficacious photodynamic therapy of cancer.

Targeted and effective drug transport is becoming an attractive option in cancer therapy since it can improve drug efficacy and reduce drugs' side effects in normal tissues. In addition to using specific surface ligand molecules, the selective drug delivery can be accomplished via enhanced permeability and retention effect. Therefore, in our studies, we entrapped zinc (II) phthalocyanine (ZnPc) - a second generation photosensitizer - in folate-functionalized micelles of the biocompatible, FDA-approved for biomedical application diblock copolymer methoxypoly(ethylene oxide)-b-poly(L-lactide) (mPEG-b-PLLA) and its derivative with folate (FA) attached to the end of PEG chain (FA-PEG-b-PLLA). Dynamic light scattering (DLS) measurements confirmed the micellar size to be <150 nm in diameter, a low polydispersity index, and good colloid stability of the studied nanocarriers, while atomic force microscopy (AFM) was used to study their morphology. The application potential of the resulting micelles was evaluated in cyto- and photocytotoxicity studies in conjunction with intracellular distribution and accumulation imaging of the photosensitizer delivered to ovarian carcinoma (SKOV-3) and metastatic melanoma (Me45) cell lines. Reactive oxygen species generation study was performed after photodynamic reaction, and cellular cytoskeleton reorganization was visualized after undergoing a photodynamic reaction. The results demonstrated that the functionalized polymeric micelles are promising nanocarriers for photodynamic therapy procedures and can be used in anticancer drug delivery.

Expression of peptide transporter 1 has a positive correlation in protoporphyrin IX accumulation induced by 5-aminolevulinic acid with photodynamic detection of non-small cell lung cancer and metastatic brain tumor specimens originating from non-small cell lung cancer.

Recently, 5-aminolevulinic acid (5-ALA)-induced protoporphyrin IX fluorescence was reported to be a useful tool during total surgical resection of high-grade gliomas. However, the labeling efficacy of protoporphyrin IX fluorescence is lower in metastatic brain tumors compared to that in high-grade gliomas, and the mechanism underlying protoporphyrin IX fluorescence in metastatic brain tumors remains unclear. Lung cancer, particularly non-small cell lung cancer (NSCLC), is the most common origin for metastatic brain tumor. Therefore, we investigated the mechanism of protoporphyrin IX fluorescence in NSCLC and associated metastatic brain tumors. Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) was employed to evaluate the protein and mRNA levels of five transporters and enzymes involved in the porphyrin biosynthesis pathway: peptide transporter 1 (PEPT1), hydroxymethylbilane synthase (HMBS), ferrochelatase (FECH), ATP-binding cassette 2 (ABCG2), and heme oxygenase 1 (HO-1). The correlation between protein, mRNA, and protoporphyrin IX levels in NSCLC cells were evaluated in vitro. Immunohistochemistry was used to determine proteins that played a key role in intraoperative protoporphyrin IX fluorescence in clinical samples from patients with NSCLC and pathologically confirmed metastatic brain tumors. A significant correlation between PEPT1 expression and protoporphyrin IX accumulation in vitro was identified by western blotting (P = 0.003) and qRT-PCR (P = 0.04). Immunohistochemistry results indicated that there was a significant difference in PEPT1 between the intraoperative protoporphyrin IX fluorescence-positive and protoporphyrin IX fluorescence-negative groups (P = 0.009). Expression of PEPT1 was found to be positively correlated with 5-ALA-induced protoporphyrin IX accumulation detected by photodynamic reaction in metastatic brain tumors originating from NSCLC.

The Structures, Spectroscopic Properties, and Photodynamic Reactions of Three [RuCl(QN)NO]- Complexes (HQN = 8-Hydroxyquinoline and Its Derivatives) as Potential NO-Donating Drugs.

The structures and spectral properties of three ruthenium complexes with 8-hydroxyquinoline (Hhqn) and their derivatives 2-methyl-8-quinolinoline (H2mqn) and 2-chloro-8-quiolinoline (H2cqn) as ligands (QN = hqn, 2mqn, or 2cqn) were calculated with density functional theory (DFT) at the B3LYP level. The UV-Vis and IR spectra of the three [RuCl(QN)NO]− complexes were theoretically assigned via DFT calculations. The calculated spectra reasonably correspond to the experimentally measured spectra. Photoinduced NO release was confirmed through spin trapping of the electron paramagnetic resonance spectroscopy (EPR), and the dynamic process of the NO dissociation upon photoirradiation was monitored using time-resolved infrared (IR) spectroscopy. Moreover, the energy levels and related components of frontier orbitals were further analyzed to understand the electronic effects of the substituent groups at the 2nd position of the ligands on their photochemical reactivity. This study provides the basis for the design of NO donors with potential applications in photodynamic therapy.

Ultrasensitive redox-responsive porphyrin-based polymeric nanoparticles for enhanced photodynamic therapy

Stimulus-sensitive nanoparticles (NPs) have been established to widely adapt to remarkable abnormalities under the tumor microenvironment, which can observably enhance the therapeutic efficiency, improve the specific targeting ability and reduce the side effects. Photodynamic therapy (PDT) as a promising non-invasive and selective treatment for cancers through photodynamic reaction can profit from stimulus-sensitive NPs. Herein, a harmonious amphiphilic polymer (PEG-b-PTPPDS-b-PEG) with an extremely sensitive redox response is constructed via click chemistry between N3-TPPC6-N3, PEG-N3 and alkynyl-containing disulfide ester for PDT. This polymer can be self-assembled into micelles with excellent stability, ultra-fast sensitivity of redox-triggered porphyrin release, and significant photodynamic anticancer performance. The redox-triggered dissociation of micelles and the release of porphyrin are much faster than common porphyrin-containing polymer. The bio-distribution and phototoxicity of micelles against A549 cells are measured and evaluated in vitro by flow cytometry, confocal scanning laser microscopy (CLSM) and MTT assay, respectively. The results reveal that PEG-b-PTPPDS-b-PEG micelles can effectively enhance the cellular uptake and cellular internalization of porphyrin and have an extremely low dark toxicity with efficient PDT towards A549 cells. This intracellular responsive nanoparticle provides a potential strategy for anticancer therapeutic application.

Photodynamic therapy of cancer with liposomal photosensitizers.

The photodynamic reaction involves the light-induced generation of an excited state in a photosensitizer molecule (PS), which then results in the formation of reactive oxygen species in the presence of oxygen, or a direct modification of a cellular molecule. Most PSs are porphyrinoids, which are highly lipophilic, and are administered usually in liposomes to facilitate their effective delivery to target cells. The currently available liposomal formulations are Visudyne® and Fospeg®. Novel PSs were developed and tested for their photodynamic activity against cancer cells. Several compounds were highly phototoxic to oral cancer cells both in free and liposome-encapsulated form, with nanomolar IC50 values. The lowest IC50s (7-13nM) were obtained with a PS encapsulated in cationic liposomes.

P-10 - Oxidative stress induced by UV-B and sunlight mediated photoactivation of carbazole inhibits normal human skin cells physiology

Solar ultraviolet (UV) radiation causes skin cancer after prolongs exposure. Carbazole (CBZ) has a tricyclic structure and is produced from fossil fuels, cigarette smoke, eye kohl, black tattoo ink, coal and wood combustion. We have studied the photomodification of CBZ under UV-B (0.9mw/cm2) and sunlight. Phototoxicity of CBZ was done on human skin keratinocytes (HaCaT) through MTT, NRU and cell migration assays. CBZ generates reactive oxygen species (ROS) through type-I photodynamic reaction and measured through H2DCFDA and DHE fluorescence in cells. Photosensitized CBZ induced apoptosis which was confirmed through sub-G1 fraction, morphological changes, cytochrome c and caspase-12 release from mitochondria and ER, PS translocation, CPDs/6,4PPs/MN formation. Our RT-PCR and western blot results strongly supports our view point of apoptotic cell death through up-regulation of pro-apoptotic genes followed by antioxidant genes keap-1, nrf-2 and hmox-1. Therefore, much attention should be paid to concomitant exposure of carbazole and UV-R for its total environmental impact.

Nanopurpurin-based photodynamic therapy destructs extracellular matrix against intractable tumor metastasis

Nanomaterials-based photodynamic therapy (PDT) has been used to treat malignant cells. However, the intrinsic impact of nanomaterials-based PDT on mechanical properties of intractable tumor cells is not well understood. Herein, we demonstrated that the mechanical forces of Taxol-resistant tumor cells were decreased by nanopurpurin-based PDT destructing extracellular matrix (ECM), increasing therapy sensitivity and repressing tumor metastasis. Combining FIRMS and general confocal microscope, we observed that the disruption of ECM by photodynamic reaction of P18-nanoconfined liposome (P18⊂L) induced a decrease of adhesion force and biomechanical properties of Taxol-resistant cells through the attenuation of actomyosin-based contractility thereby inhibiting cell migration and metastasis in vivo. Moreover, the destroyed ECM by P18⊂L PDT increased the therapy sensitivity. A clearer understanding of the effect of nanopurpurin-based PDT on mechanical properties and behaviors of intractable tumor cells will provide new and important basis for developing new therapeutic strategies.

Synchronous delivery of oxygen and photosensitizer for alleviation of hypoxia tumor microenvironment and dramatically enhanced photodynamic therapy

Photosensitizer, proper laser irradiation, and oxygen are essential components for effective photodynamic therapy (PDT) in clinical cancer therapy. However, native hypoxic tumoral microenvironment is a major barrier hindering photodynamic reactions in vivo. Thus, we have prepared biocompatible liposomes by loading complexes of oxygen-carrier (hemoglobin, Hb) and photosensitizer (indocyanine green, ICG) for enhanced PDT against hypoxic tumor. Ideal oxygen donor Hb, which is an oxygen-carried protein in red blood cells, makes such liposome which provide stable oxygen supply. ICG, as a photosensitizer, could transfer energy from lasers to oxygen to generate cytotoxic reactive oxygen species (ROS) for treatment. The liposomes loading ICG and Hb (LIH) exhibited efficient tumor homing upon intravenous injection. As revealed by T2-weighted magnetic resonance imaging and immunohistochemical analysis, the intratumoral hypoxia was greatly alleviated, and the level of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in tumor was obviously down-regulated. A weak PDT efficiency was found in cells incubated in simulated hypoxia condition in vitro, while PDT effect was dramatically enhanced in LIH treated hypoxia cells under near-infrared (NIR) laser, which was mainly attributed to massive generation of ROS with sufficient oxygen supply. ROS trigger oxidative damage of tumors and induce complete suppression of tumor growth and 100% survival rate of mice, which were also in good health condition. Our work highlights a liposome-based nanomedicine that could effectively deliver oxygen to tumor and alleviate tumor hypoxia state, inducing greatly improved efficacy compared to conventional cancer PDT and demonstrates the promise of modulating unfavorable tumor microenvironment with nanotechnology to overcome limitations of cancer therapies.

Magnetic chitosan/graphene oxide composite loaded with novel photosensitizer for enhanced photodynamic therapy.

Photodynamic therapy (PDT) is an increasingly recognized alternative to treat various cancers in clinical practice. Most second-generation photosensitizers (PS) are hydrophobic and have poor targeting selectivity, which limit their efficacy for PDT. In this paper, graphene oxide (GO) coupled with magnetic Fe3O4 nanoparticles and chitosan (CS) (MCGO) was prepared by a one-pot solvothermal method and used as a nanocarrier for loading the new photosensitizer HNPa (λmax = 698 nm), which was first synthesized by our group, and was considered as a good water-soluble drug and an excellent tissue-penetrating agent due to its strong absorption at 698 nm (near-infrared region). The synthesized composite (MCGO–HNPa) showed high stability, good water solubility and biocompatibility, expected magnetic targetability, and good photostability for PDT even in low concentrations. Our research reveals that MCGO nanomaterials can promote the production and release of singlet oxygen (ΦΔ = 62.9%) when compared with free HNPa. In addition, the in vitro cell uptake experiments suggested that the MCGO nanomaterials can accelerate the penetration of HNPa drugs into the tumor cell nucleus and that the drug release behavior is pH-sensitive. The MTT assay results against human hepatoma cell lines HepG-2 clearly show that the MCGO–HNPa composite can effectively result in cell damage and apoptotic cell death under light, and that the nanocomposite can improve the PDT antitumor effect of PS agents with negligible dark toxicity. Meanwhile, the research on the photoreaction mechanism reveals that Type I and Type II photodynamic reactions can occur simultaneously in this PDT process, and their relative contributions depend on the type and dose of the photosensitizer. Type II has a greater effect on PDT than Type I, especially for a higher HNPa photosensitizer dose. All the results reveal the promising application of the presented novel strategy.

Advances in equipment for tumor sonodynamic therapy

Photodynamic therapy (PDT) is a new technique for interventional minimally invasive therapy of cancer. It has many advantages such as less trauma, low toxicity, quick recovery, good selectivity and adaptability, and repeatable/palliative treatment. It uses the photodynamic reaction between photosensitizer and oxygen molecules under the light condition, so that tumor cells can be damaged and even be killed, to cure cancer. PDT equipment is a new type of medical equipment which is used in PDT for cancer treatment. Its main components include the light source, the light transmission system, the control system and the monitoring system. Stable and flexible PDT equipment can greatly improve the curative effect of PDT, which will promote the applications of PDT clinically. This paper is mainly a summary and analysis of the vital structures of PDT equipment for cancer, including the light source, optical transmitting system, optical power and temperature detection and control system, blood oxygen concentration monitoring system, as well as the photosensitizer concentration monitoring and tumor localization devices. Light source is the most important part of the device. Different types of light sources can be used in different clinical occasion. Despite the traditional light sources such as LED or lasers, some new light sources are also invented, thus giving more choices to the clinical application. In choosing the appropriate light source, the wavelength and output power is also vital for the clinical effect. To keep the output power stable is still the challenge in the design of light sources. The optical transmitting system guides the light to the tumor in deep, which can be flexible in design according to the different organs and the structure of tissues. The parameters which are needed to be detected and controlled include the temperature, optical power, blood oxygen concentration, photosensitizer concentration. The stability of these parameters guarantee the treatment effect of individual treatment, and some new methods and techniques are invented recently and are still to be developed. Image navigation system is an auxiliary for PDT. It can be achieved by existing imaging technology such as the ultrasonic imaging and MRI. The establishment of image model can also help to analyze the therapeutic schedule and plan the route of treatment. These medical images give PDT an accurate positioning of the region of interest, so that certain regions can get the appropriate light dose, thus broaden the scope of PDT to adapt, showing great value of development. There are also techniques devoting to designing intelligent PDT instrument such as remote control and the portable devices, which will make PDT more flexible for patients to receive the treatment. At present, these structure and designs mentioned above are mostly developed separately, so the PDT equipment which integrates the fundamental structure with advanced monitoring and controlling system is required to be invented. The research and development of the devices for PDT are not relatively mature and specialized enough, and has not yet formed a commercialized scale, but some progress has been made in the key parts of PDT equipment. Nowadays most researches are focused on the light source and optical transmission structure, but there will be more development space for PDT parameters monitoring, image navigation, tumor positioning and other technological problems, which will improve the stability and reliability of PDT equipment, promoting the PDT equipment to be better used in clinical.

Photodynamic therapy in fibrosarcoma BALB/c animal model: Observation of the rebound effect

In vivo spectrofluorometric analysis during photodynamic therapy (PDT) is a fundamental tool to obtain information about drug bleaching kinetics. Using a portable spectrofluorometer with an excitation source emitting at 400nm wavelength and a spectral analyzer ranging from 500nm to 800nm, the evolution of the meta-tetra(hydroxyphenyl) chlorin (m-THPC) photosensitizer fluorescence spectrum at the tumoral tissue of BALB/c murines with fibrosarcoma located at their flank was followed up. Ex vivo fluorescence measurements of the tumor and skin were also performed with the aim of better characterizing the in vivo signal at different parts of the tumor. PDT was performed employing a LED 637nm light source. Fluorescence at different parts of the tumor and at the tail and armpit of mice was measured immediately after injection and followed daily. The average fluorescence intensity in the tumor reached a maximum after 24-72h. Subsequently, illuminations 24, 48, 72 and 96h post-injection were performed, and the fluorescence was measured immediately before and after each illumination. Eventually, 24h post-illumination, the fluorescence at certain parts of the tumor increased in comparison with that measured immediately after illumination. This effect, named "rebound effect", was due to the new local accumulation of the drug, and was used to perform a second illumination on some mice to increase the amount of photodynamic reaction and significantly improve the PDT outcome. These results are encouraging to optimize PDT in the proposed animal model, thinking about the possible translation to humans.

光増感反応の不整脈アブレーション治療に対する応用：PD ABLATION

光増感反応の不整脈アブレーション治療に対する応用：PD ABLATION

Photodynamic therapy for biliary tract organ via a novel ultra-small composite optical fiberscope.

Photodynamic therapy (PDT) is a method used treat tumors via utilizing photodynamic reactions between photosensitive substances with tumor affinity and lasers. For overall bile duct cancers, PDT has been demonstrated to resolve stenosis and improve prognosis; however, when limited to intrahepatic bile duct cancers, modifications to the laser irradiation are necessary as surrounding hepatocytes incorporate a large amount of photosensitive substances. Furthermore, the intrahepatic bile duct is thin, and a guide sheath and thin fiber are necessary to transport laser irradiation probes to the target region. In the present study, a parallel-type ultra-small composite optical fiberscope (COF) with an outer diameter of 1 mm or smaller was developed to target a thin intrahepatic bile duct. PDT was performed using an animal model and talaporfin sodium (Laserphyrin), which is rapidly excreted by hepatocytes and is suitable for use with a long-wavelength laser due to its high tissue penetrating ability. The results demonstrated that Laserphyrin does not cause necrotic changes in the normal biliary tract mucosa. In addition, COF images of sufficient quality were acquired. The present results suggest that COF may be used for the treatment of deep bile duct lesions.

Nano artificial red cells with sufficient oxygen supply for boosted photodynamic therapy

Photodynamic therapy (PDT) has been increasingly applied in clinical cancer treatments. However, native hypoxic tumor microenvironment and lacking of oxygen supply are major barriers to potent photodynamic reactions. Here, we report smart nano artificial red cells loading photosensitizer and hemoglo

Irradiance dependence of the conduction block of an in vitro cardiomyocyte wire

BackgroundTo obtain therapeutic condition precisely by in vitro experiment, we studied the irradiance dependence of the electrical conduction blockage caused by a photodynamic reaction using a high extracellular concentration of talaporfin sodium on a novel in vitro cardiomyocyte electrical conduction wire. MethodsThe cardiomyocyte wires were constructed on patterned cultivation cover glass, which had cultivation areas 60μm in width, and a maximum length of 10mm. The talaporfin sodium concentration was set to 20μg/mL. The photodynamic reaction with a high extracellular photosensitizer concentration was performed with a short time interval (approximately 15min) between photosensitizer exposure and irradiation. A 663-nm laser was applied to the cardiomyocyte wire, and the irradiance was varied between 3 and 120mW/cm2. The cardiomyocyte electrical conduction was evaluated using the cross-correlation function of intracellular Ca2+ probe fluorescence brightness from an upper and lower section outside the laser irradiation area of a wire every 10s, which lasted up to 600s. ResultsThe onset of electrical conduction blockage was defined by an 85% decrease in the cross-correlation function, compared with its initial value. The time for the electrical conduction blockage decreased from 600 to 300s as the irradiance was increased. Also, the probability of electrical conduction blockage was found to increase with increasing irradiance. ConclusionsWe found a strong dependence on the irradiance for the time and probability of electrical conduction blockage.

Advances in equipment for tumor photodynamic therapy

Photodynamic therapy (PDT) is a new technique for interventional minimally invasive therapy of cancer. It has many advantages such as less trauma, low toxicity, quick recovery, good selectivity and adaptability, and repeatable/palliative treatment. It uses the photodynamic reaction between photosensitizer and oxygen molecules under the light condition, so that tumor cells can be damaged and even be killed, to cure cancer. PDT equipment is a new type of medical equipment which is used in PDT for cancer treatment. Its main components include the light source, the light transmission system, the control system and the monitoring system. Stable and flexible PDT equipment can greatly improve the curative effect of PDT, which will promote the applications of PDT clinically. This paper is mainly a summary and analysis of the vital structures of PDT equipment for cancer, including the light source, optical transmitting system, optical power and temperature detection and control system, blood oxygen concentration monitoring system, as well as the photosensitizer concentration monitoring and tumor localization devices. Light source is the most important part of the device. Different types of light sources can be used in different clinical occasion. Despite the traditional light sources such as LED or lasers, some new light sources are also invented, thus giving more choices to the clinical application. In choosing the appropriate light source, the wavelength and output power is also vital for the clinical effect. To keep the output power stable is still the challenge in the design of light sources. The optical transmitting system guides the light to the tumor in deep, which can be flexible in design according to the different organs and the structure of tissues. The parameters which are needed to be detected and controlled include the temperature, optical power, blood oxygen concentration, photosensitizer concentration. The stability of these parameters guarantee the treatment effect of individual treatment, and some new methods and techniques are invented recently and are still to be developed. Image navigation system is an auxiliary for PDT. It can be achieved by existing imaging technology such as the ultrasonic imaging and MRI. The establishment of image model can also help to analyze the therapeutic schedule and plan the route of treatment. These medical images give PDT an accurate positioning of the region of interest, so that certain regions can get the appropriate light dose, thus broaden the scope of PDT to adapt, showing great value of development. There are also techniques devoting to designing intelligent PDT instrument such as remote control and the portable devices, which will make PDT more flexible for patients to receive the treatment. At present, these structure and designs mentioned above are mostly developed separately, so the PDT equipment which integrates the fundamental structure with advanced monitoring and controlling system is required to be invented. The research and development of the devices for PDT are not relatively mature and specialized enough, and has not yet formed a commercialized scale, but some progress has been made in the key parts of PDT equipment. Nowadays most researches are focused on the light source and optical transmission structure, but there will be more development space for PDT parameters monitoring, image navigation, tumor positioning and other technological problems, which will improve the stability and reliability of PDT equipment, promoting the PDT equipment to be better used in clinical.

The influence of photodynamic reaction on the human ovarian and breast cancer cells in vitro

The influence of photodynamic reaction on the human ovarian and breast cancer cells in vitro