Improved photothermal therapy of brain cancer cells and photogeneration of reactive oxygen species by biotin conjugated gold photoactive nanoparticles.

Herein, we report on the design and development of functionalized acrylic polymeric nanoparticles with Spiropyrans (SPs) and imidazole moieties via superficial polymerizations. Then, Au3+ ions were immobilized and reduced on their surface to obtain photoresponsive gold-decorated polymer nanoparticles(Au-NPs). The synthesized Au-NPs were surface adapted with biotin as specific targeting tumor penetration cells and enhance the intercellular uptake through the endocytosis. FT-IR (Fourier-transform Infrared Spectroscopy), UV-Vis (Ultra Violet-Visible Spectrophotometer), EDS (Energy Dispersive X-Ray Spectroscopy), SEM (Scanning Electron Microscope) and HR-TEM (High-resolution transmission electron microscopy) descriptions were engaged to illustrate their spectral analysis and morphological examinations of Bt@Au-NPs. Fluorescence microscopy images of cellular uptake descriptions and ICP-MS (Inductively coupled plasma mass spectrometry) investigation established the cell lines labeling ability and enhanced targetting efficacy of biotin-conjugated Au-NPs (Bt@Au-NPs) toward C6 glioma cells (brain cancer cells) with 72.5% cellular uptake relative to 30.2% for non-conjugated lone. These were further established through intracellular ROS examinations and in vitro cytotoxicity investigation on the C6 glioma cell line. The solid surface plasmon absorptions of the Au-NPs and Bt@Au-NPs providing raised photothermal therapy under UV irradiation. The synthesized multifunctional Bt@Au-NPs with an inclusive combination of potential resources presented encouraging nanoprobe with targeting capability, improved photodynamic and photothermal cancer therapy.

Self-assembled Camptothecin derivatives - Curcuminoids conjugate for combinatorial chemo-photodynamic therapy to enhance anti-tumor efficacy.

Camptothecin (CPT), an alkaloid, was first discovered from plants and has potent anti-tumor activity. Since then, CPT analogs (namely Irinotecan and Topotecan) have been approved by the FDA for cancer treatments. Curcumin, on the other hand, is a widely used photosensitizer in photodynamic therapy (PDT) treatment. In our previous work, we have reported a straightforward strategy to construct a drug self-delivery system in which two-molecular species Irinotecan and Curcumin can self-assembly into a complex of ion pairs, namely ICN, through intermolecular non-covalent interactions. We found that ICN has slightly better chemotherapy efficacy than its individual components with much fewer side effects. In this paper, we aim to combine the chemotherapy and the PDT of ICN to further improve its anti-tumor performance. The efficient cellular uptake of ICNs was observed by confocal microscopy. Dichloro-dihydro-fluorescein diacetate (DCFH-DA) assay was used to detect the generation of singlet oxygen species. We found that the cell viability was 9% with both chemotherapy and PDT, and 31% with chemotherapy alone for the case with an ICN concentration of 10 µM, which demonstrated that the anti-tumor efficacy against the HT-29 cancer cell line was enhanced substantially with the combination therapy strategy. The study with an in vivo mouse model has further verified that the chemo-PDT dual therapy can inhibit tumor growth by 84% and 18.8% comparing with the control group and the chemotherapy group, respectively. Our results demonstrated that the new strategy using self-assembly and carrier-free nanoparticles with their chemo-PDT dual therapy may provide new opportunities to develop future combinatorial therapy methods in treating cancer.

Dual-targeted 5-aminolevulinic acid derivatives with glutathione depletion function for enhanced photodynamic therapy.

Photodynamic therapy (PDT) is a promising tumor therapy which utilizes reactive oxygen species (ROSs) to cause tumor cells death. 5-aminolevulinic acid (ALA) and two of its esters are FDA-approved photosensitizers. However, their clinical application suffers from their instability and lack of tumor selectivity. In addition, the overexpression of glutathione (GSH) in some tumor cells reduces the PDT efficiency due to the ROS-scavenging ability of GSH. In this work, we present three multifunctional ALA derivates with the characteristics of dual-targeting and GSH depletion to improve the therapeutic effect of ALA-based PDT. The general structure of these compounds consists of an ALA methyl ester (ALA-OMe) moiety that can metabolize to photosensitive protoporphyin IX (PpIX) inside the cells, a biotin group for targeting biotin receptor-positive tumor cells and a disulfide bond-based self-immolative linker which can be activated by GSH to liberate ALA-OMe. Simultaneously, the reaction between the disulfide bond and GSH also depletes intracellular GSH, causing tumor cells more vulnerable to ROSs. All three compounds exhibited high stability under physiological conditions. In vitro experiments demonstrated that the more lipophilic compounds 1 and 2 were much more efficient in inducing PpIX production in biotin receptor-overexpressed HeLa cells as compared with their parent compound (ALA-OMe). And the PpIX generation induced by compounds 1 and 2 was positively correlated with the overexpression of biotin receptor and GSH level in tumor cells. More importantly, the GSH depletion ability of them significantly increased their phototoxicity. Furthermore, in comparison with ALA-OMe, compound 2 showed much higher in vivo efficiency in PpIX production. All the results demonstrate that the combination strategy of dual-targeting and GSH depletion can be used to concurrently enhance the tumor-specificity and anti-tumor efficiency of ALA-based PDT. And this strategy may be used for designing other ALA-based photosensitizers with higher tumor-specificity and better therapeutic effects.

Effect of light emitting diode photobiomodulation on murine macrophage function after Bothrops envenomation.

Several reports have suggested that photobiomodulation, owing to its analgesic, anti-inflammatory, and healing effects, may be an effective therapeutic option for local effects of snakebites when the availability and accessibility of conventional serum therapy are inefficient and far from medical care centers. Although there have been studies that demonstrate the application of photobiomodulation in the treatment of local adverse events due to snakebites from snakes of the genus Bothrops, its role in the activation of leukocytes, particularly macrophages, has not been evaluated. Here, we assessed the effect of light-emitting diode (LED) treatment on macrophage activation induced by B. jararacussu venom (BjV). LED treatment caused an increase in the viability of macrophages incubated with BjV. This treatment reduced reactive oxygen species (ROS) and nitric oxide (NO) production by macrophages after incubation with BjV. However, LED treatment did not interfere with IL-1ß and IL-10 production by macrophages after incubation with BjV. In conclusion, this study showed that LED treatment has the potential to be used in combination with conventional serum therapy to prevent or minimize the progression of local to severe symptoms after Bothrops envenomation.

Delivery systems exploiting natural cell transport processes of macromolecules for intracellular targeting of Auger electron emitters.

The presence of Auger electrons (AE) among the decay products of a number of radionuclides makes these radionuclides an attractive means for treating cancer because these short-range electrons can cause significant damage in the immediate vicinity of the decomposition site. Moreover, the extreme locality of the effect provides a potential for selective eradication of cancer cells with minimal damage to adjacent normal cells provided that the delivery of the AE emitter to the most vulnerable parts of the cell can be achieved. Few cellular compartments have been regarded as the desired target site for AE emitters, with the cell nucleus generally recognized as the preferred site for AE decay due to the extreme sensitivity of nuclear DNA to direct damage by radiation of high linear energy transfer. Thus, the advantages of AE emitters for cancer therapy are most likely to be realized by their selective delivery into the nucleus of the malignant cells. To achieve this goal, delivery systems must combine a challenging complex of properties that not only provide cancer cell preferential recognition but also cell entry followed by transport into the cell nucleus. A promising strategy for achieving this is the recruitment of natural cell transport processes of macromolecules, involved in each of the aforementioned steps. To date, a number of constructs exploiting intracellular transport systems have been proposed for AE emitter delivery to the nucleus of a targeted cell. An example of such a multifunctional vehicle that provides smart step-by-step delivery is the so-called modular nanotransporter, which accomplishes selective recognition, binding, internalization, and endosomal escape followed by nuclear import of the delivered radionuclide. The current review will focus on delivery systems utilizing various intracellular transport pathways and their combinations in order to provide efficient targeting of AE to the cancer cell nucleus.

Self-Assembled Naphthalimide Conjugated Porphyrin Nanomaterials with D-A Structure for PDT/PTT Synergistic Therapy.

Light-activated phototherapy, including photothermal and photodynamic therapy, has become a new way for spatiotemporal control and noninvasive treatment of cancer. In this study, two new organic porphyrin molecules (NI-Por and NI-ZnPor) with donor (D)-acceptor (A) structure were designed and synthesized. The donor-acceptor pairs facilitated the intermolecular electron transfer, resulting in the enhancement of near-infrared (NIR) absorbance and nonradiative heat generation. After self-assembling, the nanoparticles were formed with the size around 60 nm. Relative to that of organic molecules, the absorption of NI-Por NPs and NI-ZnPor NPs broadened and red-shifted to the near-infrared region. Moreover, the porphyrin-containing nanoparticles can generate heat and reactive oxygen species (ROS) simultaneously induced by a single laser (635 nm). The intracellular reactive oxygen species production of NI-Por NPs and NI-ZnPor NPs was confirmed using DCFH-DA as an indicator. Furthermore, the localization of NI-Por NP and NI-ZnPor NP in HeLa cells was verified by fluorescence confocal laser microscopy. The photocytoxicity of two nanoparticles against HeLa cells was evaluated through the CCK-8 method. The IC50 of NI-Por NPs and NI-ZnPor NPs upon 635 nm laser irradiation was calculated to be 6.92 µg/mL and 5.86 µg/mL, respectively. Furthermore, the PDT/PTT synergistic effect of NPs under a 635 nm laser was verified through different treatment groups in vitro. All these results demonstrated that the as-prepared porphyrin-based nanoparticles are promising nanoagents for PDT/PTT in clinic.

Macrophage-Mediated Bystander Effects after Different Irradiations through a p53-dependent Pathway.

The goal of this work was to elucidate the mechanisms of bystander effects outside the localized irradiation field and their potential hematological toxicity. In this study, an in vitro multicellular co-culture system was used to investigate the intercellular commutation and related signaling pathways between either irradiated A549 cells or Beas-2B cells and bystander lymphoblast TK6 cells with or without macrophage U937 cells as an intermediator. Results showed that the proliferation ability of bystander TK6 cells was inhibited after co-culture with A549 cells irradiated with γ rays rather than carbon ions. When macrophages were contained in the co-culture system, the cell viability damage to the bystander TK6 cells were further enhanced. However, the proliferation inhibition of bystander TK6 cells after co-culture with irradiated Beas-2B cells was observed only when intermediator macrophages existed in the cell co-culture system. More serious cell injury was detected after carbon-ion irradiation compared with γ-ray irradiation. The p53-relevant apoptosis pathway was activated in both irradiated A549 and Beas-2B cells, each to a different extent. When the p53 pathway of irradiated cells was inhibited by PFT-α, PFTµ or p53 siRNA, the bystander damage to TK6 cells were clearly alleviated. In conclusion, the bystander lymphoblast damage was induced in different cells using different LET radiations. An amplified bystander response was modulated by the intermediator macrophage. The underlying molecular mechanisms of these bystander effects were dependent on the activation of p53 and its relevant apoptosis pathway in the irradiated cells. These results suggest that the bystander and macrophage-mediated bystander effects contribute to the common acute side effect of lymphocytopenia after local irradiation.

Near-Infrared Photoactivatable Semiconducting Polymer Nanoblockaders for Metastasis-Inhibited Combination Cancer Therapy.

Inhibition of protein biosynthesis is a promising strategy to develop new therapeutic modalities for cancers; however, noninvasive precise regulation of this cellular event in living systems has been rarely reported. In this study, a semiconducting polymer nanoblockader (SPNB ) is developed that can inhibit intracellular protein synthesis upon near-infrared (NIR) photoactivation to synergize with photodynamic therapy (PDT) for metastasis-inhibited cancer therapy. SPNB is self-assembled from an amphiphilic semiconducting polymer which is grafted with poly(ethylene glycol) conjugated with a protein biosynthesis blockader through a singlet oxygen (1 O2 ) cleavable linker. Such a designed molecular structure not only enables generation of 1 O2 under NIR photoirradiation for PDT, but also permits photoactivation of blockaders to terminate protein translation. Thereby, SPNB exerts a synergistic action to afford an enhanced therapeutic efficacy in tumor ablation. More importantly, SPNB -mediated photoactivation of protein synthesis inhibition precisely and remotely downregulates the expression levels of metastasis-related proteins in tumor tissues, eventually contributing to the complete inhibition of lung metastasis. This study thus proposes a photoactivatable protherapeutic design for metastasis-inhibited cancer therapy.

Zinc oxide nanoparticles synthesized from Allium cepa prevents UVB radiation mediated inflammation in human epidermal keratinocytes (HaCaT cells).

The extensive relevance of nanoparticles arouses the requirement for manufacturing although the predictable technique are frequently perilous and energy saving. In the current study, zinc oxide nanoparticles manufactured from Allium cepa avert UVB radiation interceded irritation in human epidermal keratinocytes (HaCaT cells). In the current study, the zinc oxide nanoparticles (ZnO-NPs) was synthesized from the extract of A. cepa. The optimized ZnO-NPs hence attained and was enumerated and exemplified by UV visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscope (SEM) and EDAX impending analysis. In addition, amalgamated ZnO-NPs were experienced for cell viability (MTT), formation of reactive oxygen species (ROS), apoptosis, and antioxidant and lipid peroxidation (TBARS) levels. Also, we explored the effect of A. cepa ZnO-NPs in molecular level by evaluating the inflammatory and apoptotic markers, in which ZnO-NPs reinstated the interleukins 6, 10 and related signaling molecules like iNOS, COX-2 levels. Ultimately, ZnO-NPs induce apoptotic markers (Bax, Bcl-2) and also recommended that ZnO-NPs might aggravate cancer cell apoptosis in HaCaT cells.

A Novel Photosensitizer Znln2S4 Mediated Photodynamic Therapy Induced-HepG2 Cell Apoptosis.

Photodynamic therapy (PDT) uses a combination of photosensitizers with visible light to generate reactive species and selectively kill tumor or unwanted tissue. Znln2S4 nanoparticles are widely implemented in photovoltaic device materials and photolysis water catalysts owing to their unique photoelectric properties. Whether Znln2S4 itself can be used as an effective dye in PDT is still unknown. To determine the effects and potential mechanism of Znln2S4PDT on HepG2 cell apoptosis, electron microscopic analysis was performed to monitor the apoptotic morphology of HepG2 cells upon exposure to Znln2S4-PDT. Flow cytometry was performed to measure the apoptosis rate and intracellular ROS production. Western blot and ELISA were performed to reveal the expression changes in Bax, caspase-3 and caspase-9. Data from this work suggested that cells exhibited the typical apoptotic morphology in response to Znln2S4-PDT, with high apoptotic rate. The intracellular ROS production after Znln2S4-PDT occurred in a dose-dependent manner. Moreover, Znln2S4-PDT augmented the expression levels of pro-apoptosis factors, especially, Bax, caspase-3 and caspase-9. Taken together, our novel findings, Znln2S4-PDT elicited HepG2 cell apoptosis, suggesting Znln2S4 as a promising photosensitizer candidate for cancer therapy.

Cellular transformations in near-infrared light-induced apoptosis in cancer cells revealed by label-free CARS imaging.

Photobiomodulation (PBM) involves light to activate cellular signaling pathways leading to cell proliferation or death. In this work, fluorescence and Coherent anti-Stokes Raman Scattering (CARS) imaging techniques were applied to assess apoptosis in human cervical cancer cells (HeLa) induced by near infrared (NIR) laser light (808 nm). Using the Caspase 3/7 fluorescent probe to identify apoptotic cells, we found that the pro-apoptotic effect is significantly dependent of irradiation dose. The highest apoptosis rate was noted for the lower irradiation doses, that is, 0.3 J/cm2 (~58%) and 3 J/cm2 (~28%). The impact of light doses on proteins/lipids intracellular metabolism and distribution was evaluated using CARS imaging, which revealed apoptosis-associated reorganization of nuclear proteins and cytoplasmic lipids after irradiation with 0.3 J/cm2 . Doses of NIR light causing apoptosis (0.3, 3 and 30 J/cm2 ) induced a gradual increase in the nuclear protein level over time, in contrast to proteins in cells non-irradiated and irradiated with 10 J/cm2 . Furthermore, irradiation of the cells with the 0.3 J/cm2 dose resulted in lipid droplets (LDs) accumulation, which was apparently caused by an increase in reactive oxygen species (ROS) generation. We suggest that PBM induced apoptosis could be caused by the ability of NIR light to trigger excessive LDs formation which, in turn, induces cellular cytotoxicity.

Multinuclear Ru(ii) and Ir(iii) decorated tetraphenylporphyrins as efficient PDT agents.

Two novel porphyrin-core systems were prepared by Sonogashira cross-coupling of the terminal alkyne groups of meso-tetra(4-ethynylphenyl)porphyrin-Zn(ii) (P-1) with halogenated Ru(ii)- or Ir(iii)-phenanthroline complexes. The resulting compounds (P-Ru and P-Ir) were spectroscopically characterised and their photophysical properties were investigated (λem 625, 665 nm; τT 339.6 µs (P-Ru) and λem 530, 612, 664 nm; τT 396.6 µs (P-Ir)). Nanosecond time-resolved transient absorption studies were used to explore the 3MLCT nature of the triplet excited states, and the singlet oxygen quantum yields were determined (ΦΔ 44.8 (P-Ru), 33.2 (P-Ir)%). The subcellular uptake of P-Ru and P-Ir and their application as photosensitisers (PS) in photodynamic therapy (PDT) were explored due to their solution photophysics and absence of dark toxicity. Upon irradiation (λexc = 620-630 nm; 10 min; 33 J cm-2), both P-Ru and P-Ir killed 90% of SKBR-3 cells at 1 µM. Notably P-Ru induced a 77% decrease in cell viability at only 0.25 µM.

Exploring subcellular responses of prostate cancer cells to X-ray exposure by Raman mapping.

Understanding the response of cancer cells to ionising radiation is a crucial step in modern radiotherapy. Raman microspectroscopy, together with Partial Least Squares Regression (PLSR) analysis has been shown to be a powerful tool for monitoring biochemical changes of irradiated cells on the subcellular level. However, to date, the majority of Raman studies have been performed using a single spectrum per cell, giving a limited view of the total biochemical response of the cell. In the current study, Raman mapping of the whole cell area was undertaken to ensure a more comprehensive understanding of the changes induced by X-ray radiation. On the basis of the collected Raman spectral maps, PLSR models were constructed to elucidate the time-dependent evolution of chemical changes induced in cells by irradiation, and the performance of PLSR models based on whole cell averages as compared to those based on average Raman spectra of cytoplasm and nuclear region. On the other hand, prediction of X-ray doses for individual cellular components showed that cytoplasmic and nuclear regions should be analysed separately. Finally, the advantage of the mapping technique over single point measurements was verified by a comparison of the corresponding PLSR models.

Photoprotective and Anti-Inflammatory Properties of Vina-Ginsenoside R7 Ameliorate Ultraviolet B-Induced Photodamage in Normal Human Dermal Fibroblasts.

Vina-ginsenoside R7 (R7) has been exhibited to engage in multiple pharmacological activities, such as antioxidant and anti-inflammatory activities. However, no photoaging-related studies have been performed on R7. Research is being conducted with the aim of assessing whether treatment with R7 has a protective effect on UVB-induced photoaging skin. Our results show that UVB exposure directly reduces matrix metalloproteinase (MMP) secretion through R7 by restraining the AP-1/MAPK pathway and blocks extracellular matrix (ECM) expression degradation. In addition, R7 improves the expression of transforming growth factor beta 1 (TGF-ß1), and type I procollagen also facilitates the synthesis of collagen by the TGF-ß/Smad signal transduction pathway. Finally, R7 valid blocks nuclear factor-κB (NF-κB) activation and enhances antioxidative stress capacity through activated nuclear factor (erythroid derived 2)-like 2 (Nrf2). In particular, the application of R7 restrains pro-inflammatory cytokines (TNF-α, IL-6, iNOS), which trigger ECM, degrade enzyme production, and suppress vascular endothelial growth factor (VEGF) secretion. In conclusion, R7 may constitute a promising cosmetic ingredient that can protect against skin photodamage resulting from detrimental UVB irradiation.

Doppler fluctuation spectroscopy of intracellular dynamics in living tissue.

Intracellular dynamics in living tissue are dominated by active transport driven by bioenergetic processes far from thermal equilibrium. Intracellular constituents typically execute persistent walks. In the limit of long mean free paths, the persistent walks are ballistic, exhibiting a "Doppler edge" in light scattering fluctuation spectra. At shorter transport lengths, the fluctuations are described by lifetime-broadened Doppler spectra. Dynamic light scattering from transport in the ballistic, diffusive, or the crossover regimes is derived analytically, including the derivation of autocorrelation functions through a driven damped harmonic oscillator analog for light scattering from persistent walks. The theory is validated through Monte Carlo simulations. Experimental evidence for the Doppler edge in three-dimensional (3D) living tissue is obtained using biodynamic imaging based on low-coherence interferometry and digital holography.

Stimuli responsive PEGylated bismuth selenide hollow nanocapsules for fluorescence/CT imaging and light-driven multimodal tumor therapy.

Stimuli-responsive therapeutic nanosystems exhibit enhanced selectivity and higher biosafety for cancer theranostics via recognizing exogenous or endogenous tumor-associated factors. Herein, we developed a multifunctional nanocomplex (Bi2Se3@PEG/DOX/Ce6 nanocapsules, or BPDC NCs in brief) which was constructed by loading chlorin e6 (Ce6) and doxorubicin (DOX) into PEGylated hollow bismuth selenide nanocapsules. Upon administration of BPDC NCs, composite laser irradiation can effectively activate the local hyperthermia generation and the yield of cytotoxic reactive oxygen species (ROS). In another aspect, on-demand drug release can be triggered in a mild acidic tumor microenvironment or by thermal shock. Moreover, imaging and navigation with respect to infrared thermography, computed tomography (CT) and fluorescence imaging may potentially monitor the biodistribution of BPDC NCs, thanks to the local hyperthermia generation, fluorescence emission of Ce6 and high Z-element of bismuth. Finally, we demonstrated tumor site-specific photothermal therapy (PTT), photodynamic therapy (PDT) and chemotherapeutic effects for highly efficacious tumor suppression with minimized systemic toxicity. Taken together, these findings indeed provide insights that can broaden the application of Bi2Se3 nanocapsules for cancer management and precision medicine.

Microwave diathermy induces mitogen-activated protein kinases and tumor necrosis factor-α in cultured human monocytes.

Although rehabilitation practice for most patients consists of a combined use of thermotherapy that is produced from diathermy devices resulting faster and deeper heating to the patient, major concerns about occupational exposure to electromagnetic radiation for the operators must be considered. In most occasions, physiotherapists have involved multi-hour treatment sessions to different patients, resulting overuse of the diathermy device. Recently, our team along with other groups have raised serious concerns about the occupational safety aspects related to microwave diathermy (MWD) use. Driven by these recent reports, in this work, we tried to investigate the in vitro effects of a physiotherapist routine MWD device regarding its potential inflammatory biological effects that could be evoked in human cultured monocytes. Our results show that MWD does not alter the integrity of the cell membrane and, consequently, the viability of monocytes as assessed by Trypan blue and MTT measurements. Then again, members of the MAPK family (p38 and ERK1/2) were activated upon MWD exposure at 5-30 min, eventually leading to a time-dependent considerable increase in TNF-α production, a key pro-inflammatory mediator. Our results are indicative of a stress-activated phenomenon of monocytes upon MWD radiation, which could trigger potential hazardous cellular outcomes due to thermal and/or non-thermal bystander effects. Our results deserve further investigation, planned by our team in due course, to delineate the clinical correlations of these findings.

Superoxide Radical Photogenerator with Amplification Effect: Surmounting the Achilles' Heels of Photodynamic Oncotherapy.

Strong oxygen dependence, poor tumor targeting, and limited treatment depth have been considered as the "Achilles' heels" facing the clinical usage of photodynamic therapy (PDT). Different from common approaches, here, we propose an innovative tactic by using photon-initiated dyad cationic superoxide radical (O2-•) generator (ENBOS) featuring "0 + 1 > 1" amplification effect to simultaneously overcome these drawbacks. In particular, by taking advantage of the Förster resonance energy transfer theory, the energy donor successfully endows ENBOS with significantly enhanced NIR absorbance and photon utility, which in turn lead to ENBOS more easily activated and generating more O2-• in deep tissues, that thus dramatically intensifies the type I PDT against hypoxic deep tumors. Moreover, benefiting from the dyad cationic feature, ENBOS achieves superior "structure-inherent targeting" abilities with the signal-to-background ratio as high as 25.2 at 48 h post intravenous injection, offering opportunities for accurate imaging-guided tumor treatment. Meanwhile, the intratumoral accumulation and retention performance are also markedly improved (>120 h). On the basis of these unique merits, ENBOS selectively inhibits the deep-seated hypoxic tumor proliferation at a low light-dose irradiation. Therefore, this delicate design may open new horizons and cause a paradigm change for PDT in future cancer therapy.

Radiofrequency radiation at 2.856 GHz does not affect key cellular endpoints in neuron-like PC12 cells.

To investigate the potential cytotoxicity of radiofrequency (RF) radiation on central nervous system, rat pheochromocytoma (PC12) cells were exposed to 2.856 GHz RF radiation at a specific absorption rate (SAR) of 4 W/kg for 8 h a day for 2 days in 35 mm Petri dishes. During exposure, the real-time variation of the culture medium temperature was monitored in the first hour. Reactive oxygen species (ROS) production, intracellular Ca2+ concentration, and cell apoptosis rate were assessed immediately after exposure by flow cytometry. The results showed that the medium temperature raised about 0.93 °C, but no significant changes were observed in apoptosis, ROS levels or intracellular Ca2+ concentration after treatment. Although several studies suggested that RF radiation does indeed cause neurological effects, this study presented inconsistent results, indicating that 2.856 GHz RF radiation exposure at a SAR of 4 W/kg does not have a dramatic impact on PC12 cells, and suggests the need for further investigation on the key cellular endpoints of other nerve cells after exposure to RF radiation.

Variations of Intracellular Ca2+ Mobilization Initiated by Nanosecond and Microsecond Electrical Pulses in HeLa Cells.

GOAL: Herein, the variations in transient Ca2+ mobilizations in HeLa cells exposed to a single, non-thermal pulsed electric field (PEF) are described. METHODS: Three PEF waveforms categorized by pulse duration and intensity were used to deduce the kinetics involved in Ca2+ mobilization. A fast microscopic fluorescent imaging system and a fluorescent molecular probe were used to observe transient intracellular Ca2+ mobilization after pulse exposure. The sources and pathways in the transient Ca2+ mobilizations were investigated using an inhibitor of inositol-1,4,5-trisphosphate receptor (IP3R) on the endoplasmic reticulum (ER) along with a Ca2+-free buffer. RESULTS: When exposed to the 10-µs-long PEF, the Ca2+ concentration increased mainly at the cathodic region near the membrane. However, Ca2+ concentration increased at both anodic and cathodic regions when Na+ concentration in the buffer was reduced. Ca2+ concentration increased only in the presence of extracellular Ca2+. CONCLUSION: These results suggest that the 10-µs PEF takes a large amount of extracellular Na+ into the cell through the electropermeabilized plasma membrane, especially at the anodic side, resulting in the suppression of the Ca2+ influx. On the contrary, the 20-ns-long PEF increased Ca2+ concentration in the surrounding region of the nucleus only in the presence of extracellular Ca2+. The PEF exposure with inhibition of the IP3R indicates that increased Ca2+ ions are released from the ER via the activated IP3R. SIGNIFICANCE: These mechanisms could induce specific cell responses, such as Ca2+ oscillations, Ca2+ waves, and Ca2+ puffs.