Photodynamic therapy (PDT) uses photosensitizers and visible light in combination with molecular oxygen to produce reactive oxygen species (ROS) that kill malignant cells by apoptosis and/or necrosis, shut down the tumor microvasculature and stimulate the host immune system. The excited singlet state of oxygen ( 1 O 2 ) is recognized to be the main cytotoxic ROS generated during PDT for the majority of photosensitizers used clinically and for many investigational new agents, so that maximizing its production within tumor cells and tissues can improve the therapeutic response, and several emerging and novel approaches for this are summarized. Quantitative techniques for 1 O 2 production measurement during photosensitization are also of immense importance of value for both preclinical research and future clinical practice. In this review, emerging strategies for enhanced photosensitized 1 O 2 generation are introduced, while recent advances in direct detection and imaging of 1 O 2 luminescence are summarized. In addition, the correlation between cumulative 1 O 2 luminescence and PDT efficiency will be highlighted. Meanwhile, the validation of 1 O 2 luminescence dosimetry for PDT application is also considered. This review concludes with a discussion on future demands of 1 O 2 luminescence detection for PDT dosimetry, with particular emphasis on clinical translation.Eye-catching color image for graphical abstract.

Based on blood plasma surface-enhanced Raman spectroscopy (SERS) analysis, a simple and label-free blood test for non-invasive cervical cancer detection is presented in this paper. SERS measurements were performed on blood plasma samples from 60 cervical cancer patients and 50 healthy volunteers. Both the empirical approach and multivariate statistical techniques, including principal component analysis (PCA) and linear discriminant analysis (LDA), were employed to analyze and differentiate the obtained blood plasma SERS spectra. The empirical diagnostic algorithm based on the integration area of the SERS spectral bands (1310-1430 and 1560-1700 cm(-1)) achieved a diagnostic sensitivity of 70% and 83.3%, and a specificity of 76% and 78%, respectively, whereas the diagnostic algorithms based on PCA-LDA yielded a better diagnostic sensitivity of 96.7% and a specificity of 92% for separating cancerous samples from normal samples. This exploratory work demonstrates that a silver nanoparticle based SERS plasma analysis technique in conjunction with PCA-LDA has potential for improving cervical cancer detection and screening.

The purpose of this study is to investigate the feasibility for quantitative measurement of singlet oxygen ((1)O(2)) generation by using a newly developed (1)O(2)-specific fluorescence probe Singlet Oxygen Sensor Green reagent (SOSG). (1)O(2) generation from photoirradiation of a model photosensitizer Rose Bengal (RB), in initially air-statured phosphate buffered saline (PBS) was indirectly monitored with SOSG. In the presence of (1)O(2), SOSG can react with (1)O(2) to produce SOSG endoperoxides (SOSG-EP) that emit strong green fluorescence with the maximum at 531 nm. The green fluorescence of SOSG-EP is mainly dependent on the initial concentrations of RB and SOSG, and the photoirradiation time for (1)O(2) generation. Furthermore, kinetic analysis of the RB-sensitized photooxidation of SOSG is performed that, for the first time, allows quantitative measurement of (1)O(2) generation directly from the determination of reaction rate. In addition, the obtained (1)O(2) quantum yield of porphyrin-based photosensitizer hematoporphyrin monomethyl ether (HMME) in PBS by using SOSG is in good agreement with the value that independently determined by using direct measurement of (1)O(2) luminescence. The results of this study clearly demonstrate that the quantitative measurement of (1)O(2) generation using SOSG can be achieved by determining the reaction rate with an appropriate measurement protocol.

Near‐infrared (NIR) emitting materials have attracted considerable attention because of their potential applications in organic light emitting diodes, bioimaging, military, etc. The research on NIR‐emitting materials and devices is motivated by fundamental and practical application demands. In these developed NIR‐emitting materials, transition metal complexes, and thermally activated delayed fluorescence (TADF) molecules, which can harvest triplet excitons, have exhibited significant potential because their theoretical internal quantum efficiency can reach 100%. Herein, the development of these NIR‐emitting materials of transition metal complexes and TADF molecules is reviewed and, furthermore, a clear outlook for a broad range of applications in many disciplinary areas is provided.

Polymeric micelles are emerging as an effective drug delivery system for hydrophobic photosensitizers in photodynamic therapy (PDT). The objective of this study was to investigate the formulation of hydrophobic protoporphyrin IX (PpIX) with MePEG(5000)-b-PCL(4100) [methoxy poly (ethylene glycol)-b-poly (caprolactone)] diblock copolymers and to compare their PDT response to that of free PpIX. The photophysical and photochemical properties of the polymeric PpIX micelles were studied by measuring absorbance and fluorescence spectra, PpIX-loading efficiency and stability, the micelle particle size and morphology, as well as singlet oxygen luminescence and lifetime. The spherical micelles have a high PpIX-loading efficiency of 82.4% and a narrow size distribution with a mean diameter of 52.2 +/- 6.4 nm. The cellular uptake of PpIX in RIF-1 cells using PpIX micelles was approximately two-fold higher than that for free PpIX. Free PpIX and PpIX formulated in micelles exhibited similar subcellular localization in or around the cellular plasma membrane, as demonstrated using fluorescence microscopy. In vitro PDT results showed that the PpIX micelles have markedly increased photocytotoxicity over that with free PpIX, by nearly an order of magnitude at the highest light dose used. The micelles alone had no evident phototoxicity or dark toxicity. These findings suggest that MePEG(5000)-b-PCL(4100) diblock copolymer micelles have great potential as a drug delivery system for hydrophobic photodynamic sensitizers.