Large-scale sensitivity adjustment for Gd-HMME room temperature phosphorescence oxygen sensing.

The oxygen sensing enhancement based on room temperature phosphorescence (RTP) of Gd-HMME adjusted by imidazole was studied. The phosphorescence intensity IP0 and the Stern-Volmer equations under different imidazole concentration were obtained, and the physical mechanism of imidazole regulating the oxygen quenching constant KSV was analyzed. It was found that the KSV value increased by ∼46 folds in the range of 12.4(1)-576.1(5) kPa-1, and the large-scale variation of KSV is conducive to the realization of high precision oxygen concentration measurement in a wide range. In addition, the standard deviation σ of continuous measurement results was given, and the limit of detection (LOD) was determined to be 6.6 ppm.

Involvement of hydrogen peroxide in sonodynamical effect with sinoporphyrin sodium in hypoxic situation.

Sonodynamic therapy (SDT) represents a noninvasive therapeutic method via the activation of certain chemical sensitizers using low-intensity ultrasound to generate various reactive oxygen species (ROS). In this work, we conducted systematic experiments to evaluate the production of hydrogen peroxide (H2O2) in sinoporphyrin sodium (DVDMS) mediated SDT (DVDMS-SDT). We found that the fluorescence intensities of H2O2-specific probe BES-H2O2 and Amplex Red increased significantly exposure to DVDMS-SDT while decreased with the introduction of catalase (H2O2 scavenger), indicating the production of H2O2. And the fluorescence intensity of H2O2 susceptible probes were positively correlated with DVDMS concentration, ultrasound intensity and irradiation time. Under the same molarity concentration, DVDMS has advantages over proto-porphyrin IX (PpIX) and hemoporrin monomethyl ether (HMME) in H2O2 production, indicating that the yield of H2O2 depends on the properties of sensitizer. More importantly, DVDMS-SDT is involved in the process of H2O2 even in the oxygen-free condition, showing its greater superiority for the treatment of tumor under hypoxia environment.

Investigation of high-concentration doping performance based on Er3+-ion-doped Ba6Gd2Ti4O17.

Recently, various strategies have been explored during research into the use of lanthanide-doped luminescent materials to mitigate energy loss at elevated dopant concentrations. Herein we report Yb3+/Er3+ co-doped Ba6Gd2Ti4O17 (BGTO) phosphors with a laminated lattice structure, which can allow the high-concentration doping of Er3+ ions into the oxide. Detailed investigations into the luminescence properties and crystal structures of Yb3+/Er3+ co-doped BGTO reveal that an increase in the dopant concentration is associated with the dimensional limitation of energy transfer in the crystal lattice. This finding may provide a novel avenue for the construction of high-dopant-concentration UC luminescent materials.

An effective oxygen content detection in phosphorescence of PtOEP-C6/Poly (St-co-TFEMA).

The phosphorescence of PtOEP-C6/Poly (St-co-TFEMA) has been investigated to achieve an accurate oxygen content, which is always puzzled as its extreme temperature sensitivity. The relations of oxygen content and phosphorescence intensity ratio can be perfectly fitted by the Stern-Volmer equation at different temperatures, meanwhile the monotonic quenching constant KSV is obtained, which enables us to develop a method of temperature correction to realize the intrinsic oxygen content. Then a clear fundamental picture of the temperature quenching mechanism of PtOEP is drawn by the time-resolved spectroscopy, the temperature sensitivity of phosphorescence arises from the enhanced quenching effect of oxygen by temperature. Our results provide an effective method to gain accurate oxygen content by simple optical measurement.

Reactive oxygen species explicit dosimetry to predict local tumor growth for Photofrin-mediated photodynamic therapy.

Although photodynamic therapy (PDT) is an established modality for cancer treatment, current dosimetric quantities, such as light fluence and PDT dose, do not account for the differences in PDT oxygen consumption for different fluence rates (ϕ). A macroscopic model was adopted to calculate reactive oxygen species concentration ([ROS]rx) to predict Photofrin-PDT outcome in mice bearing radiation-induced fibrosarcoma (RIF) tumors. Singlet oxygen is the primary cytotoxic species for ROS, which is responsible for cell death in type II PDT, although other type I ROS is included in the parameters used in our model. Using a combination of fluences (50-250 J∕cm2) and ϕ (75 or 150 mW∕cm2), tumor regrowth rate, k, was determined for each condition by fitting the tumor volume versus time to V0 *exp(k*t). Treatment was delivered with a collimated laser beam of 1 cm diameter at 630 nm. Explicit dosimetry of light fluence rate on tissue surface, tissue oxygen concentration, tissue optical properties, and Photofrin concentration were performed. Light fluence rate at 3 mm depth (ϕ 3mm) was determined for the treatment volume based on Monte-Carlo simulations and measured tissue optical properties. Initial tissue oxygenation [3 O 2]0 was measured by an Oxylite oxygen probe before PDT and used to calculate [ROS]rx,calc. This value was compared to [ROS]rx,meas as calculated with the entire tissue oxygen spectrum [3 O 2](t), measured over the duration of light delivery for PDT. Cure index, CI = 1-k/kctr , for tumor growth up to 14 days after PDT was predicted by four dose metrics: light fluence, PDT dose, and [ROS]rx,calc, and [ROS]rx,meas. PDT dose was defined as the product of the time-integral of photosensitizer concentration and ϕ at a 3 mm tumor depth. These studies show that [ROS]rx,meas best correlates with CI and is an effective dosimetric quantity that can predict treatment outcome.

Reactive oxygen species explicit dosimetry to predict tumor growth for benzoporphyrin derivative-mediated vascular photodynamic therapy.

Photodynamic therapy (PDT) is a well-established treatment modality for cancer and other malignant diseases; however, quantities such as light fluence and PDT dose do not fully account for all of the dynamic interactions between the key components involved. In particular, fluence rate (ϕ) effects, which impact the photochemical oxygen consumption rate, are not accounted for. In this preclinical study, reacted reactive oxygen species ([ROS]rx) was investigated as a dosimetric quantity for PDT outcome. The ability of [ROS]rx to predict the cure index (CI) of tumor growth, CI = 1 - k / kctr, where k and kctr are the growth rate of tumor under PDT study and the control tumor without PDT, respectively, for benzoporphyrin derivative (BPD)-mediated PDT, was examined. Mice bearing radiation-induced fibrosarcoma (RIF) tumors were treated with different in-air fluences (Φ = 22.5 to 166.7 J / cm2) and in-air fluence rates (ϕair = 75 to 250 mW / cm2) with a BPD dose of 1 mg / kg and a drug-light interval (DLI) of 15 min. Treatment was delivered with a collimated laser beam of 1-cm-diameter at 690 nm. Explicit measurements of in-air light fluence rate, tissue oxygen concentration, and BPD concentration were used to calculate for [ROS]rx. Light fluence rate at 3-mm depth (ϕ3 mm), determined based on Monte-Carlo simulations, was used in the calculation of [ROS]rx at the base of tumor. CI was used as an endpoint for three dose metrics: light fluence, PDT dose, and [ROS]rx. PDT dose was defined as the product of the time-integral of photosensitizer concentration and ϕ3 mm. Preliminary studies show that [ROS]rx best correlates with CI and is an effective dosimetric quantity that can predict treatment outcome. The threshold dose for [ROS]rx for vascular BPD-mediated PDT using DLI of 15 min is determined to be 0.26 mM and is about 3.8 times smaller than the corresponding value for conventional BPD-mediated PDT using DLI of 3 h.

Reactive Oxygen Species Explicit Dosimetry for Photofrin-mediated Pleural Photodynamic Therapy.

Explicit dosimetry of treatment light fluence and implicit dosimetry of photosensitizer photobleaching are commonly used methods to guide dose delivery during clinical PDT. Tissue oxygen, however, is not routinely monitored intraoperatively even though it is one of the three major components of treatment. Quantitative information about in vivo tissue oxygenation during PDT is desirable, because it enables reactive oxygen species explicit dosimetry (ROSED) for prediction of treatment outcome based on PDT-induced changes in tumor oxygen level. Here, we demonstrate ROSED in a clinical setting, Photofrin-mediated pleural photodynamic therapy, by utilizing tumor blood flow information measured by diffuse correlation spectroscopy (DCS). A DCS contact probe was sutured to the pleural cavity wall after surgical resection of pleural mesothelioma tumor to monitor tissue blood flow (blood flow index) during intraoperative PDT treatment. Isotropic detectors were used to measure treatment light fluence and photosensitizer concentration. Blood-flow-derived tumor oxygen concentration, estimated by applying a preclinically determined conversion factor of 1.5 × 109 µMs cm-2 to the blood flow index, was used in the ROSED model to calculate the total reacted reactive oxygen species [ROS]rx. Seven patients and 12 different pleural sites were assessed and large inter- and intrapatient heterogeneities in [ROS]rx were observed although an identical light dose of 60 J cm-2 was prescribed to all patients.

Reactive oxygen species explicit dosimetry to predict local tumor control for Photofrin-mediated photodynamic therapy.

Although photodynamic therapy (PDT) is an established modality for cancer treatment, current dosimetric quantities, such as light fluence and PDT dose, do not account for the differences in PDT oxygen consumption for different fluence rates (ϕ). A macroscopic model was adopted to calculate reactive oxygen species concentration ([ROS]rx) to predict Photofrin-PDT outcome in mice bearing radiation-induced fibrosarcoma (RIF) tumors. Singlet oxygen is the primary cytotoxic species for ROS, which is responsible for cell death in type II PDT, although other type I ROS is included in the parameters used in our model. Using a combination of fluences (50-250 J/cm2) and ϕ (50 - 150 mW/cm2), tumor regrowth rate, k, was determined for each condition by fitting the tumor volume vs. time to V0*exp(k*t). Treatment was delivered with a collimated laser beam of 1 cm diameter at 630 nm. Explicit dosimetry of initial tissue oxygen concentration, tissue optical properties, and Photofrin concentration was used to calculate [ROS]rx,cal. ϕ was determined for the treatment volume based on Monte-Carlo simulations and measured tissue optical properties. Tissue oxygenation is measured using an oxylite oxygen probe to throughout the treatment to calculate the measured [ROS]rx,mea. Cure index, CI = 1-k/k ctr , for tumor gowth up to 14 days were determined as an endpoint using five dose metrics: light fluence, PDT dose, and [ROS]rx,cal, and [ROS]rx,mea. PDT dose was defined as the product of the time-integral of photosensitizer concentration and ϕ at a 3 mm tumor depth. Preliminary studies show that [ROS]rx,mea best correlates with CI and is an effective dosimetric quantity that can predict treatment outcome.

Reactive oxygen species explicit dosimetry to predict tumor growth for BPD-mediated vascular photodynamic therapy.

Photodynamic therapy (PDT) is a well-established treatment modality for cancer and other malignant diseases; however, quantities such as light fluence, and PDT dose do not fully account for all of the dynamic interactions between the key components involved. In particular, fluence rate (ϕ) effects are not accounted for, which has a large effect on the oxygen consumption rate. In this preclinical study, reacted reactive oxygen species ([ROS]rx) was investigated as a dosimetric quantity for PDT outcome. We studied the ability of [ROS]rx to predict the cure index (CI) after PDT of murine tumors; CI = 1 - k/kctr, where k and kctr are the growth rate of PDT-treated and control(untreated) tumor, respectively. Mice bearing radiation induced fibrosarcoma (RIF) tumors were treated with BPD-mediated PDT at different in-air fluences (22.5, 40, 45, 50, 70 and 100 J/cm2) and in-air ϕ (75 and 150 mW/cm2) with a BPD dose of 1 mg/kg and a drug-light interval of 15 mins. Treatment was delivered with a collimated laser beam of 1 cm diameter at 690 nm. Explicit dosimetry of initial tissue oxygen concentration, tissue optical properties, and BPD concentration was used to calculate [ 1 O 2 ] rx . ϕ was calculated for the treatment volume based on Monte-Carlo simulations and measured tissue optical properties. CI was used as an endpoint for four dose metrics: light fluence, PDT dose, and [ROS]rx. PDT dose was defined as the product of the time-integral of photosensitizer concentration and ϕ at a 3 mm tumor depth. Preliminary studies show that [ROS]rx best correlates with CI and is an effective dosimetric quantity that can predict treatment outcome. The threshold dose for [ROS]rx is determined to be 0.23 mM and is about 4.3 times smaller than the corresponding value for conventional BPD-mediated PDT using DLI of 3 hrs.

Photoluminescence properties and spectral structure analysis of NaLn(MoO4)2:Eu3+ (Ln = Gd, Y) phosphors.

In this paper, a facile synthetic route for the preparation of NaLn(MoO4)2:Eu3+ (Ln = Gd, Y) nanocrystals by a hydrothermal method is reported. The NaLn(MoO4)2:Eu3+ (Ln = Gd, Y) micro-powders were synthesized by a high temperature solid-state reaction. The optical properties of Eu3+ as a local structural probe are analyzed when being incorporated into NaLn(MoO4)2 (Ln = Gd, Y) micro-powders and nanocrystals. In NaLn(MoO4)2:Eu3+ (Ln = Gd, Y), the substitution of Ln3+ by Eu3+ is confirmed and the point symmetry of the site and crystal structure are analyzed. The luminescence mechanism and the size dependence of their fluorescence properties in NaLn(MoO4)2:Eu3+ (Ln = Gd, Y) micro-powders and nanocrystals are also discussed in detail.