scholarly journals Radiative and Non-Radiative Decay Pathways in Carbon Nanodots toward Bioimaging and Photodynamic Therapy

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 70
Author(s):  
Yujin Kim ◽  
Yoonsang Park ◽  
Seulgi Han ◽  
Wonchan Park ◽  
Mungu Kim ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Radiative Decay ◽  
Near Infrared ◽  
Energy State ◽  
Carbon Nanodots ◽  
Ros Generation ◽  
Trap States ◽  
Different Types ◽  
Energy States

The origin and classification of energy states, as well as the electronic transitions and energy transfers associated with them, have been recognized as critical factors for understanding the optical properties of carbon nanodots (CNDs). Herein, we report the synthesis of CNDs in an optimized process that allows low-temperature carbonization using ethanolamine as the major precursor and citric acid as an additive. The results obtained herein suggest that the energy states in our CNDs can be classified into four different types based on their chemical origin: carbogenic core states, surface defective states, molecular emissive states, and non-radiative trap states. Each energy state is associated with the occurrence of different types of emissions in the visible to near-infrared (NIR) range and the generation of reactive oxygen species (ROS). The potential pathways of radiative/non-radiative transitions in CNDs have been systematically studied using visible-to-NIR emission spectroscopy and fluorescence decay measurements. Furthermore, the bright photoluminescence and ROS generation of these CNDs render them suitable for in vitro imaging and photodynamic therapy applications. We believe that these new insights into the energy states of CNDs will result in significant improvements in other applications, such as photocatalysis and optoelectronics.

Folic Acid Functionalized Chlorin e6-Superparamagnetic Iron Oxide Nanocarriers as a Theranostic Agent for MRI-Guided Photodynamic Therapy

2021 ◽  
Vol 17 (2) ◽  
pp. 205-215
Author(s):  
Zhenbo Sun ◽  
Mingfang Luo ◽  
Jia Li ◽  
Ailing Wang ◽  
Xucheng Sun ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Folic Acid ◽  
Iron Oxide ◽  
Near Infrared ◽  
Biological Fluids ◽  
Superparamagnetic Iron Oxide ◽  
Chlorin E6 ◽  
Theranostic Agent

Imaging-guided cancer theranostic is a promising strategy for cancer diagnostic and therapeutic. Photodynamic therapy (PDT), as an approved treatment modality, is limited by the poor solubility and dispersion of photosensitizers (PS) in biological fluids. Herein, it is demonstrated that superparamagnetic iron oxide (SPIO)-based nanoparticles (SCFs), prepared by conjugated with Chlorin e6 (Ce6) and modified with folic acid (FA) on the surface, can be used as versatile drug delivery vehicles for effective PDT. The nanoparticles are great carriers for photosensitizer Ce6 with an extremely high loading efficiency. In vitro fluorescence imaging and in vivo magnetic resonance imaging (MRI) results indicated that SCFs selectively accumulated in tumor cells. Under near-infrared laser irradiation, SCFs were confirmed to be capable of inducing low cell viability of RM-1 cells In vitro and displaying efficient tumor ablation with negligible side effects in tumor-bearing mice models.

scholarly journals A self-assembled Ru–Pt metallacage as a lysosome-targeting photosensitizer for 2-photon photodynamic therapy

2019 ◽  
Vol 116 (41) ◽  
pp. 20296-20302 ◽  
Author(s):  
Zhixuan Zhou ◽  
Jiangping Liu ◽  
Juanjuan Huang ◽  
Thomas W. Rees ◽  
Yiliang Wang ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Near Infrared ◽  
Building Blocks ◽  
Cell Uptake ◽  
Photon Absorption ◽  
In Vivo Studies ◽  
Infrared Light ◽  
Ros Generation ◽  
Multicellular Spheroids

Photodynamic therapy (PDT) is a treatment procedure that relies on cytotoxic reactive oxygen species (ROS) generated by the light activation of a photosensitizer. The photophysical and biological properties of photosensitizers are vital for the therapeutic outcome of PDT. In this work a 2D rhomboidal metallacycle and a 3D octahedral metallacage were designed and synthesized via the coordination-driven self-assembly of a Ru(II)-based photosensitizer and complementary Pt(II)-based building blocks. The metallacage showed deep-red luminescence, a large 2-photon absorption cross-section, and highly efficient ROS generation. The metallacage was encapsulated into an amphiphilic block copolymer to form nanoparticles to encourage cell uptake and localization. Upon internalization into cells, the nanoparticles selectively accumulate in the lysosomes, a favorable location for PDT. The nanoparticles are almost nontoxic in the dark, and can efficiently destroy tumor cells via the generation of ROS in the lysosomes under 2-photon near-infrared light irradiation. The superb PDT efficacy of the metallacage-containing nanoparticles was further validated by studies on 3D multicellular spheroids (MCS) and in vivo studies on A549 tumor-bearing mice.

scholarly journals Plasmonic Hot-Electron Reactive Oxygen Species Generation: Fundamentals for Redox Biology

2020 ◽  
Vol 8 ◽  
Author(s):  
Elisa Carrasco ◽  
Juan Carlos Stockert ◽  
Ángeles Juarranz ◽  
Alfonso Blázquez-Castro
Keyword(s):  
Reactive Oxygen Species ◽  
Near Infrared ◽  
Chemical Reactivity ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Ros Generation ◽  
Oxygen Species ◽  
Hot Electron ◽  
Redox Biology

For decades, the possibility to generate Reactive Oxygen Species (ROS) in biological systems through the use of light was mainly restricted to the photodynamic effect: the photoexcitation of molecules which then engage in charge- or energy-transfer to molecular oxygen (O2) to initiate ROS production. However, the classical photodynamic approach presents drawbacks, like per se chemical reactivity of the photosensitizing agent or fast molecular photobleaching due to in situ ROS generation, to name a few. Recently, a new approach, which promises many advantages, has entered the scene: plasmon-driven hot-electron chemistry. The effect takes advantage of the photoexcitation of plasmonic resonances in metal nanoparticles to induce a new cohort of photochemical and redox reactions. These metal photo-transducers are considered chemically inert and can undergo billions of photoexcitation rounds without bleaching or suffering significant oxidative alterations. Also, their optimal absorption band can be shape- and size-tailored in order to match any of the near infrared (NIR) biological windows, where undesired absorption/scattering are minimal. In this mini review, the basic mechanisms and principal benefits of this light-driven approach to generate ROS will be discussed. Additionally, some significant experiments in vitro and in vivo will be presented, and tentative new avenues for further research will be advanced.

Oxygen dependence of redox state of copper in cytochrome oxidase in vitro

1993 ◽  
Vol 74 (4) ◽  
pp. 1622-1627 ◽  
Author(s):  
Y. Hoshi ◽  
O. Hazeki ◽  
M. Tamura
Keyword(s):  
Respiratory Rate ◽  
Cytochrome Oxidase ◽  
Near Infrared ◽  
Energy State ◽  
Oxygen Affinity ◽  
Quantitative Information ◽  
Low Oxygen ◽  
Straight Line ◽  
Oxygen Concentrations

To obtain quantitative information about tissue oxygenation from near-infrared signals, the oxygen dependencies of the redox states of both heme a+a3 and copper in cytochrome oxidase of isolated mitochondria were determined at low oxygen concentrations (10(-6)-10(-9) M) using leghemoglobin as an oxygen indicator. The maximum absorbance changes caused by the aerobic-anaerobic transition measured at 830–760 nm of copper in state 3, state 4, and the uncoupled state were 10, 17, and 5% of those at 605–620 nm of heme a+a3, respectively. Thus the relative absorbance ratio of copper to heme a+a3 could be used as a sensitive indicator for the mitochondrial energy state. The oxygen concentrations required for the half-maximal reduction of heme a+a3 varied with the energy state and the respiratory rate and were 7.8 x 10(-8) and 1.6 x 10(-7) M in state 4 and state 3, respectively. In contrast, that of copper was 7.5 x 10(-8) M and was independent of both the energy state and the respiratory rate. The relationship between the percent oxidation of heme a+a3 and copper in the aerobic-anaerobic transition did not show a straight-line relationship. This was referred to as the difference in oxygen affinity between these two chromophores. The deviation from the straight line was larger in state 3 than in state 4.(ABSTRACT TRUNCATED AT 250 WORDS)

Discovery of a Monoiodo Aza-BODIPY Near-Infrared Photosensitizer: in vitro and in vivo Evaluation for Photodynamic Therapy

2020 ◽  
Vol 63 (17) ◽  
pp. 9950-9964 ◽  
Author(s):  
Zhiliang Yu ◽  
Junliang Zhou ◽  
Xin Ji ◽  
Guangyu Lin ◽  
Shuang Xu ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Near Infrared ◽  
In Vivo Evaluation

Li-Doped ZnO Nanoparticles as Novel Direct Generator of Singlet Oxygen for Potential Photodynamic Therapy Applications

2015 ◽  
Vol 1784 ◽  
Author(s):  
Milton A. Martínez Julca ◽  
Ivonnemary Rivera ◽  
Oscar Perales-Pérez ◽  
Sonia Bailón ◽  
Melina Pérez
Keyword(s):  
Photodynamic Therapy ◽  
Singlet Oxygen ◽  
Zno Nanoparticles ◽  
Band Gap Energy ◽  
Shallow Donor ◽  
Emission Peak ◽  
Ros Generation ◽  
Trap States ◽  
Li Doping ◽  
Doped Zno

ABSTRACTPhotodynamic therapy (PDT) is an alternative to traditional cancer treatments. This approach involves the use of photosensitizer (PS) agents and their interaction with light. As a consequence, cytotoxic reactive oxygen species (ROS) are generated that, in turn will destroy tumors. On the other hand, ZnO is a biocompatible, nontoxic, and biodegradable material with the capability to generate ROS, specifically singlet oxygen (SO), which makes this material a promising candidate for 2-photon PDT. Doping ZnO with Li species is expected to induce defects in the host oxide structure that favors the formation of trap states that should affect the electronic transitions related to the generation of SO. The present work reports the effect of the level of Li-doping on the ZnO structure and its capability to generate SO. Li-doped ZnO nanoparticles were synthesized under size-controlled conditions using a modified version of the polyol method. XRD measurements confirmed the development of well-crystallized ZnO Wurtzite; the average crystallite sizes ranged between 13.3nm and 14.2 nm, with an increase in Li content. The corresponding band gap energy values, estimated from UV-vis measurements, decreased from 3.33 to 3.25 eV. Photoluminescence (PL) measurements of Li-ZnO revealed the presence of emission peaks centered on 363nm, 390nm, and 556 nm; these emission peaks correspond to the exciton emission, transition of shallow donor levels near of the conduction band to valence band such as interstitial Zn, and oxygen vacancies, respectively. The observed increase of the emission intensity of the 390 nm emission peak, relative to the intensity of the main emission peak at 363nm, was attributed to the promote of trap states due to interstitial Zn or Li-incorporation into the host oxide lattice. SO measurements evidenced the enhancing effect of the Li concentration on the capability of the doped ZnO to generate this species. This Li-dependence of SO generation can be attributed to the enhancement of the concentration of trap states in the host ZnO, as suggested by PL measurements. Accordingly, Li-ZnO would become cytotoxic to cancer cells via photo-induced ROS generation enabling this nanomaterial to be considered as a potential direct PS agent for the 2-photon PDT route.

scholarly journals Multifunctional AIE Iridium (III) Photosensitizer Nanoparticles for Two-Photon-Activated Imaging and Mitochondria Targeting  Photodynamic Therapy

2021 ◽  
Author(s):  
Xuzi Cai ◽  
Kangnan Wang ◽  
Wen Ma ◽  
yuanyuan Yang ◽  
Gui Chen ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Water Solubility ◽  
Redox Homeostasis ◽  
Tissue Imaging ◽  
Ros Generation ◽  
Generation Efficiency ◽  
Deep Tissue ◽  
Two Photon ◽  
Targeting Ability

Abstract Developing novel photosensitizers for deep tissue imaging and efficient photodynamic therapy (PDT) remains a challengebecause of the poor water solubility, low reactive oxygen species (ROS) generation efficiency, serve dark cytotoxicity, and weak absorption in the NIR region of conventional photosensitizers. Herein,cyclometalated iridium (III) complexes(Ir)with aggregation-induced emission (AIE) feature, high photoinduced ROS generation efficiency, two-photonexcitation, and mitochondria-targetingcapability were designed and further encapsulated into biocompatible nanoparticles (NPs).The Ir-NPs can be used to disturb redox homeostasis in vitro, result in mitochondrial dysfunction and cell apoptosis. Importantly, invivo experiments demonstrated that theIr-NPs presented obviously tumor-targeting ability, excellent antitumor effect, and low systematic dark-toxicity. Moreover, the Ir-NPs could serve as a two-photon imaging agent for deep tissue bioimaging with a penetration depth of up to 300 μm. This work presents a promising strategy for designing a clinical application of multifunctional Ir-NPs toward bioimaging and PDT.

scholarly journals Precise and Efficient Phototheranostics: Molecular Engineering of Photosensitizers with Near-Infrared Aggregation-Induced Emission for Acid-Triggered Nucleus-Targeted Photodynamic Cancer Therapy

2020 ◽  
Author(s):  
Zhijun Zhang ◽  
Wenhan XU ◽  
Peihong Xiao ◽  
Miaomiao Kang ◽  
Dingyuan Yan ◽  
...  
Keyword(s):  
Cancer Therapy ◽  
Targeted Delivery ◽  
Near Infrared ◽  
Fluorescence Emission ◽  
Molecular Engineering ◽  
Ros Generation ◽  
Subcellular Targeting ◽  
Aggregation Induced Emission ◽  
Photodynamic Cancer Therapy

Phototheranostics involving both fluorescence imaging (FLI) and photodynamic therapy (PDT) has been recognized to be potentially powerful for cancer treatment by virtue of various intrinsic advantages. However, the state-of-the-art materials in this area are still far from ideal towards practical applications, owing to their respective and collective drawbacks, such as inefficient imaging quality, inferior reactive oxygen species (ROS) production, the lack of subcellular-targeting capability, and dissatisfactory theranostics delivery. In this contribution, these shortcomings are successfully addressed through the integration of finely engineered photosensitizers having aggregation-induced emission (AIE) features and well tailored nanocarrier system. The yielded AIE NPs simultaneously exhibit broad absorption in visible light region, bright near-infrared fluorescence emission, extremely high ROS generation, as well as tumor lysosomal acidity-activated and nucleus-targeted delivery functions, making them dramatically promising for precise and efficient phototheranostics. Both in vitro and in vivo evaluations show that the presented nanotheranostic system bearing excellent photostability and appreciable biosecurity well performed in FLI-guided photodynamic cancer therapy. This study thus not only extends the applications scope of AIE nanomaterials, but also offers useful insights into constructing a new generation of cancer theranostics.

scholarly journals Redox-Sensitive and Folate-Receptor-Mediated Targeting of Cervical Cancer Cells for Photodynamic Therapy Using Nanophotosensitizers Composed of Chlorin e6-Conjugated β-Cyclodextrin via Diselenide Linkage

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2190
Author(s):  
Howard Kim ◽  
Mi Woon Kim ◽  
Young-IL Jeong ◽  
Hoe Saeng Yang
Keyword(s):  
Cervical Cancer ◽  
Photodynamic Therapy ◽  
Hela Cells ◽  
Folate Receptor ◽  
Chlorin E6 ◽  
Ros Generation ◽  
Cervical Cancer Cells ◽  
Poly Ethylene

The aim of this study was to fabricate a reactive oxygen species (ROS)-sensitive and folate-receptor-targeted nanophotosensitizer for the efficient photodynamic therapy (PDT) of cervical carcinoma cells. Chlorin e6 (Ce6) as a model photosensitizer was conjugated with succinyl β-cyclodextrin via selenocystamine linkages. Folic acid (FA)-poly(ethylene glycol) (PEG) (FA-PEG) conjugates were attached to these conjugates and then FA-PEG-succinyl β-cyclodextrin-selenocystamine-Ce6 (FAPEGbCDseseCe6) conjugates were synthesized. Nanophotosensitizers of FaPEGbCDseseCe6 conjugates were fabricated using dialysis membrane. Nanophotosensitizers showed spherical shapes with small particle sizes. They were disintegrated in the presence of hydrogen peroxide (H2O2) and particle size distribution changed from monomodal distribution pattern to multimodal pattern. The fluorescence intensity and Ce6 release rate also increased due to the increase in H2O2 concentration, indicating that the nanophotosensitizers displayed ROS sensitivity. The Ce6 uptake ratio, ROS generation and cell cytotoxicity of the nanophotosensitizers were significantly higher than those of the Ce6 itself against HeLa cells in vitro. Furthermore, the nanophotosensitizers showed folate-receptor-specific delivery capacity and phototoxicity. The intracellular delivery of nanophotosensitizers was inhibited by folate receptor blocking, indicating that they have folate-receptor specificity in vitro and in vivo. Nanophotosensitizers showed higher efficiency in inhibition of tumor growth of HeLa cells in vivo compared to Ce6 alone. These results show that nanophotosensitizers of FaPEGbCDseseCe6 conjugates are promising candidates as PDT of cervical cancer.

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