Tin Tungstate Nanoparticles: A Photosensitizer for Photodynamic Tumor Therapy

Photon avalanche assisted upconversion via customizing the green emission

The developed SnWO₄ phosphors incorporated with Ho³⁺, Yb³⁺ and Mn⁴⁺ ions have been explored under 980 nm laser irradiation. The molar concentration of dopants has been optimized to 0.5 Ho³⁺, 3.0 Yb³⁺ and 5.0 Mn⁴⁺ in SnWO₄ phosphors. The upconversion (UC) emission from the codoped SnWO₄ phosphors has been substantially amplified up to 13 times and described based on the energy transfer and charge compensation. On incorporating the Mn⁴⁺ ions in the Ho³⁺/Yb³⁺ codoped system the sharp green luminescence shifted to reddish broadband emission due to the photon avalanche mechanism. The processes accountable for the concentration quenching have been described based on critical distance. The interaction responsible for the concentration quenching in Yb³⁺ sensitized Ho³⁺ and Ho³⁺/Mn⁴⁺:SnWO₄ phosphors is considered to be dipole-quadrupole and exchange interaction type, respectively. The activation energy 0.19 eV has been determined, and the phenomenon of thermal quenching is discussed using a configuration coordinate diagram.

Tungsten-based Nanomaterials in the Biomedical Field: A Bibliometric Analysis of Research Progress and Prospects

Tungsten-based nanomaterials (TNMs) with diverse nanostructures and unique physicochemical properties have been widely applied in the biomedical field. Although various reviews have described the application of TNMs in specific biomedical fields, there are still no comprehensive studies that summarize and analyze research trends of the field as a whole. To identify and further promote the development of biomedical TNMs, a bibliometric analysis method is used to analyze all relevant literature on this topic. First, general bibliometric distributions of the dataset by year, country, institute, referenced source, and research hotspots are recognized. Next, a comprehensive review of the subjectively recognized research hotspots in various biomedical fields, including biological sensing, anticancer treatments, antibacterials, and toxicity evaluation, is provided. Finally, the prospects and challenges of TNMs are discussed to provide a new perspective for further promoting their development in biomedical research.

Investigation of the photoluminescent properties, scintillation behaviour and toxicological profile of various magnesium tungstate nanoscale motifs

We have synthesized several morphologies and crystal structures of MgWO₄ using a one-pot hydrothermal method, producing not only monoclinic stars and large nanoparticles but also triclinic wool balls and sub-10 nm nanoparticles. Herein we describe the importance of reaction parameters in demonstrating morphology control of as-prepared MgWO₄. Moreover, we correlate structure and composition with the resulting photoluminescence and radioluminescence properties. Specifically, triclinic-phase samples yielded a photoluminescence emission of 421 nm, whereas monoclinic-phase materials gave rise to an emission maximum of 515 nm. The corresponding radioluminescence data were characterized by a broad emission peak, located at 500 nm for all samples. Annealing the wool balls and sub-10 nm particles to transform the crystal structure from a triclinic to a monoclinic phase yielded a radioluminescence (RL) emission signal that was two orders of magnitude greater than that of their unannealed counterparts. Finally, to confirm the practical utility of these materials for biomedical applications, a series of sub-10 nm particles, including as-prepared and annealed samples, were functionalized with biocompatible PEG molecules, and subsequently were found to be readily taken up by various cell lines as well as primary cultured hippocampal neurons with low levels of toxicity, thereby highlighting for the first time the potential of this particular class of metal oxides as viable and readily generated platforms for a range of biomedical applications.

Nanotechnology: A Potential Weapon to Fight against COVID-19

The COVID-19 infections have posed an unprecedented global health emergency, with nearly three million deaths to date, and have caused substantial economic loss globally. Hence, an urgent exploration of effective and safe diagnostic/therapeutic approaches for minimizing the threat of this highly pathogenic coronavirus infection is needed. As an alternative to conventional diagnosis and antiviral agents, nanomaterials have a great potential to cope with the current or even future health emergency situation with a wide range of applications. Fundamentally, nanomaterials are physically and chemically tunable and can be employed for the next generation nanomaterial-based detection of viral antigens and host antibodies in body fluids as antiviral agents, nanovaccine, suppressant of cytokine storm, nanocarrier for efficient delivery of antiviral drugs at infection site or inside the host cells, and can also be a significant tool for better understanding of the gut microbiome and SARS-CoV-2 interaction. The applicability of nanomaterial-based therapeutic options to cope with the current and possible future pandemic is discussed here.

Lactose-conjugated porphyrin: synthesis and photobiological evaluation as potential agents for photodynamic therapy

Porphyrin-based photosensitizers are conventional photodynamic agents that are used clinically. However, their clinical applications have been overshadowed by poor water solubility. In addition, they have weak tumor selectivity, which may cause undesirable side effects. The preparation of novel porphyrin derivatives has been explored for potential applications in photodynamic therapy (PDT). To achieve this goal, lactose-conjugated porphyrin nanoparticles (Lac-Por NPs) have been synthesized and characterized. PDT with Lac-Por NPs exhibited tumor-specific cytotoxicity in lactose receptor-overexpressing HepG2 cells in vitro and in vivo. In summary, we designed and synthesized lactose conjugate porphyrins with enhanced water solubility and tumor selectivity. This work expands the application range of porphyrin-based photosensitizers for cancer treatment.

Inorganic Nanomaterials with Intrinsic Singlet Oxygen Generation for Photodynamic Therapy

Inorganic nanomaterials with intrinsic singlet oxygen (1 O2 ) generation capacity, are emerged yet dynamically developing materials as nano-photosensitizers (NPSs) for photodynamic therapy (PDT). Compared to previously reported nanomaterials that have been used as either carriers to load organic PSs or energy donors to excite the attached organic PSs through a Foster resonance energy transfer process, these NPSs possess intrinsic 1 O2 generation capacity with extremely high 1 O2 quantum yield (e.g., 1.56, 1.3, 1.26, and 1.09) than any classical organic PS reported to date, and thus are facilitating to make a revolution in PDT. In this review, the recent advances in the development of various inorganic nanomaterials as NPSs, including metal-based (gold, silver, and tungsten), metal oxide-based (titanium dioxide, tungsten oxide, and bismuth oxyhalide), metal sulfide-based (copper and molybdenum sulfide), carbon-based (graphene, fullerene, and graphitic carbon nitride), phosphorus-based, and others (hybrids and MXenes-based NPSs) are summarized, with an emphasis on the design principle and 1 O2 generation mechanism, and the photodynamic therapeutic performance against different types of cancers. Finally, the current challenges and an outlook of future research are also discussed. This review may provide a comprehensive account capable of explaining recent progress as well as future research of this emerging paradigm.

Single 808 nm near-infrared-triggered multifunctional upconverting phototheranostic nanocomposite for imaging-guided high-efficiency treatment of tumors

Multifunctional phototheranostic nanocomposites are promising for early diagnosis and precision therapy of cancer. Aim to enhance their accuracy and efficiency, in this study, we develop a single-laser excited activatable phototheranostic nanocomposite (UCNPs-D-MQ): 808 nm-excited upconverting nanoparticles (UCNPs) as the matrix programmed assembly with amphipathic compound DSPE-PEG-COOH, a near-infrared absorbing polymer DPP and the pro-photosensitizer MBQB. Upon endocytosed by cancer cells and excited by the 808 nm laser, UCNPs-D-MQ could produce high-yield reactive oxygen species (ROS) as the results of singlet oxygen generation from transferring to methylene blue, GSH depletion and ROS generation from photoactivation. It was proven both in vitro and in vivo that the nanocomposites exhibits remarkable therapeutic efficacy as well as minimal photodamage to normal cells. These results reveal UCNPs-D-MQ as a robust theranostic agent for tumor phototherapy.

Photodynamic Therapy of Inorganic Complexes for the Treatment of Cancer†

Photodynamic therapy (PDT) is a medicinal tool that uses a photosensitizer and a light source to treat several conditions, including cancer. PDT uses reactive oxygen species such as cytotoxic singlet oxygen (¹ O₂ ) to induce cell death in cancer cells. Chemotherapy has historically utilized the cytotoxic effects of many metals, especially transition metal complexes. However, chemotherapy is a systemic treatment so all cells in a patient's body are exposed to the same cytotoxic effects. Transition metal complexes have also shown high cytotoxicity as PDT agents. PDT is a potential localized method for treating several cancer types by using inorganic complexes as photosensitizing agents. This review covers several in vitro and in vivo studies, as well as clinical trials that reported on the anticancer properties of inorganic pharmaceuticals used in PDT against different types of cancer.

CuWO4 Nanodots for NIR-Induced Photodynamic and Chemodynamic Synergistic Therapy

Dynamic therapy, such as photodynamic therapy (PDT) or chemodynamic therapy (CDT), is one of the most promising therapeutic strategies for tumors. Integrating the advantages of near-infrared-induced PDT and CDT can potentially improve the therapeutic performance. A single primitive nanostructure, CuWO₄ nanodots, was developed. It could generate reactive oxygen species under 808 nm light irradiation and release copper ions into the acid tumor microenvironment, thereby boosting Fenton-like reactions. The PDT and CDT would occur when the nanodots were introduced into the tumor tissue and irradiated under 808 nm light. The results of combined PDT and CDT antitumor studies showed the effective inhibition of tumor tissue growth, thereby suggesting that the nanodots are candidate agents for synergistic antitumor applications.

Recent research progress in the construction of active free radical nanoreactors and their applications in photodynamic therapy

Photodynamic therapy is the most important treatment strategy in free radical therapy. However, tumor microenvironment hypoxia is a key obstacle in PDT. In order to overcome this obstacle, the strategy of in situ production of O₂/radicals by catalytic reaction in solid tumors was proposed. In recent years, it has been found that there are many oxygen-independent carbon-based free radicals that can generate toxic active free radicals under laser irradiation and lead to tumor cell death. Based on the rational design of multifunctional nano-medicine, the active free radical nano-generator has opened up a new way for the highly developed nanotechnology and tumor cooperative therapy to improve the therapeutic effect. In this paper, the research status of active free radical nano-generators, especially reactive oxygen species, including the construction mechanism of active free radical nanomaterials, is reviewed and the application of free radical nano-generators in tumor therapy is emphasized.

Degradable Calcium Phosphate-Coated Upconversion Nanoparticles for Highly Efficient Chemo-Photodynamic Therapy

The development of a stimulus-responsive nanosystem provides an effective method for improving the accuracy and efficiency of chemotherapy. Meanwhile, traditional photodynamic therapy (PDT) has been substantially restricted by the low dosage of photosensitizer and limited penetration depth of the ultraviolet (UV) or visible light used for excitation. Here, we designed a smart multifunctional nanoplatform by coating core-shell composite mesoporous silica-encapsulated upconversion nanoparticles and chlorin e6 (Ce6) with degradable calcium phosphate, followed by the loading of doxorubicin (DOX). In our structure, the as-synthesized nanoplatform exhibits high responsiveness to a low pH value and degrades rapidly in the weakly acidic tumor microenvironment, allowing the quick release of loaded DOX in tumor sites. Interestingly, the loaded DOX, whose release depends on the pH value and positively correlates with the calcium-ion concentration, enables drug release to be monitored in real time. Combined with photosensitizer Ce6-induced PDT triggered by an 808 nm near-infrared light, synergistic chemo-photodynamic therapy is achieved, thus leading to a highly efficient anticancer treatment in vitro and in vivo. Importantly, the inherent properties of rare earth ions (Gd³⁺, Yb³⁺, and Nd³⁺) make the nanoplatform possess UCL, MRI, and CT trimode imaging capabilities, thus achieving a multiple imaging modality-guided synergistic therapy.

Preparation and Characterization of Magnetic Fe3O4/CdWO4 and Fe3O4/CdWO4/PrVO4 Nanoparticles and Investigation of Their Photocatalytic and Anticancer Properties on PANC1 Cells

Fe3O4/CdWO4 and Fe3O4/CdWO4/PrVO4 magnetic nanoparticles were prepared at different molar ratios of PrVO4 to previous layers (Fe3O4/CdWO4) via the co-precipitation method assisted by a sonochemical procedure, in order to investigate the photocatalytic performance of these systems and their cytotoxicity properties. The physico-chemical properties of these magnetic nanoparticles were determined via several experimental methods: X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier transformation infrared spectroscopy and ultraviolet-visible diffuse reflection spectroscopy, using a vibrating sample magnetometer and a scanning electron microscope. The average sizes of these nanoparticles were found to be in the range of 60-100 nm. The photocatalytic efficiency of the prepared nanostructures was measured by methylene blue degradation under visible light (assisted by H2O2). The magnetic nanosystem with a 1:2:1 ratio of three oxide components showed the best performance by the degradation of ca. 70% after 120 min of exposure to visible light irradiation. Afterwards, this sample was used for the photodegradation of methyl orange, methyl violet, fenitrothion, and rhodamine-B pollutants. Finally, the mechanism of the photocatalytic reaction was examined by releasing ˙OH under UV light in a system including terephthalic acid, as well as O2-, OH, and hole scavengers. Additionally, the cytotoxicity of each synthesized sample was assessed using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay against the human cell line PANC1 (cancer), and its IC50 was approximately 125 mg/L.

β-SnWO4 with Morphology-Controlled Synthesis and Facet-Depending Photocatalysis

Faceted β-SnWO₄ microcrystals are prepared with different morphologies including tetrahedra, truncated tetrahedra, truncated octahedra, and short-spiked and long-spiked spikecubes. All of these morphologies are prepared with comparable experimental conditions via microwave-assisted synthesis of high-boiling alcohols (the so-called polyol method). The decisive parameters for controlled formation of one or the other morphology of faceted β-SnWO₄ microcrystals are studied and discussed, including microwave-assisted heating, Sn(OH)₂ as the Sn²⁺ reservoir, the temperature of particle nucleation, the temperature of particle growth, and the concentration of the starting materials. Morphology and crystallinity are characterized by scanning electron microscopy, X-ray powder diffraction, UV-vis, and Fourier-transform infrared spectroscopy. Finally, the photocatalytic properties of all obtained faceted microcrystals-tetrahedra, truncated tetrahedra, truncated octahedra, cubes, and short-spiked and long-spiked spikecubes-are exemplarily compared with regard to the photocatalytic decomposition of rhodamine B and the influence of the respective surface crystal planes.

Photosensitizers for Photodynamic Therapy

As an emerging clinical modality for cancer treatment, photodynamic therapy (PDT) takes advantage of the cytotoxic activity of reactive oxygen species (ROS) that are generated by light irradiating photosensitizers (PSs) in the presence of oxygen (O₂ ). However, further advancements including tumor selectivity and ROS generation efficiency are still required. Substantial efforts are devoted to design and synthesize smart PSs with optimized properties for achieving a desirable therapeutic efficacy. This review summarizes the recent progress in developing intelligent PSs for efficient PDT, ranging from single molecules to delicate nanomaterials. The strategies to improve ROS generation through optimizing photoinduced electron transfer and energy transfer processes of PSs are highlighted. Moreover, the approaches that combine PDT with other therapeutics (e.g., chemotherapy, photothermal therapy, and radiotherapy) and the targeted delivery in cancer cells or tumor tissue are introduced. The main challenges for the clinical application of PSs are also discussed.

Defect engineered bioactive transition metals dichalcogenides quantum dots

Transition metal dichalcogenide (TMD) quantum dots (QDs) are fundamentally interesting because of the stronger quantum size effect with decreased lateral dimensions relative to their larger 2D nanosheet counterparts. However, the preparation of a wide range of TMD QDs is still a continual challenge. Here we demonstrate a bottom-up strategy utilizing TM oxides or chlorides and chalcogen precursors to synthesize a small library of TMD QDs (MoS₂, WS₂, RuS₂, MoTe₂, MoSe₂, WSe₂ and RuSe₂). The reaction reaches equilibrium almost instantaneously (~10–20 s) with mild aqueous and room temperature conditions. Tunable defect engineering can be achieved within the same reactions by deviating the precursors’ reaction stoichiometries from their fixed molecular stoichiometries. Using MoS₂ QDs for proof-of-concept biomedical applications, we show that increasing sulfur defects enhanced oxidative stress generation, through the photodynamic effect, in cancer cells. This facile strategy will motivate future design of TMDs nanomaterials utilizing defect engineering for biomedical applications.

Transition metal dichalcogenide (TMD) quantum dots (QDs) have promising electronic properties which might be further tailorable by defect engineering. Here the authors describe a room temperature aqueous based synthesis of TMD QDs with controlled defect concentration, and demonstrate the correlation between defect concentration and biomedical activity.

Mesoporous semiconductors combined with up-conversion nanoparticles for enhanced photodynamic therapy under near infrared light

Photodynamic therapy (PDT) is a promising and effective method for tumor therapy that relies on the reactive oxygen species (ROS) produced by photosensitizers at specific wavelengths to inhibit tumor cells. Inorganic semiconductive materials are potential photosensitizers that can excellently absorb ultraviolet light to produce ROS to kill cancer cells. However, this strategy is still limited in terms of practical applications due to the weak penetration of ultraviolet light through biological tissue, as well as the hypoxic tumor microenvironment, largely decreasing ROS generation. In this research, novel PDT agents made with mesoporous lanthanide-semiconductor composites are developed to obtain a remarkable amount of generated ROS under near-infrared (NIR) laser irradiation. Due to the larger size (about 120 nm) of the up-conversion material (UCM) used as the substrate, coated with different amounts of semiconductors with mesoporous morphologies, this platform could emit higher blue emission under a 980 nm laser. Meanwhile, both of the semiconductors (SnO₂ and TiO₂) used have wide absorbance bands in the ultraviolet region, and the ultraviolet fluorescence emitted from the UCM core under NIR laser excitation can be used as the energy donor. Electron transfer processes in SnO₂ and TiO₂ are generated via the above platforms and produce ROS through photochemical action. Furthermore, the coated semiconductors are mesoporous with larger surface areas (about 302 m² g⁻¹) and various channels; this is beneficial to obtain enough oxygen to generate more ROS under a hypoxic environment. The PDT efficiency of a typical NaYF₄@SnO₂ sample is studied using a DPBF detector, in vitro MTT assays, and in vivo tumor inhibition experiments, revealing that this lanthanide-semiconductor platform could be potentially used as a PDT agent under NIR excitation.

Photodynamic therapy (PDT) is a promising and effective method for tumor therapy that relies on the reactive oxygen species (ROS) produced by photosensitizers at specific wavelengths to inhibit tumor cells.

Y1-receptor-ligand-functionalized ultrasmall upconversion nanoparticles for tumor-targeted trimodality imaging and photodynamic therapy with low toxicity

Achieving efficient photodynamic therapy (PDT) in deeper biological tissue is still the biggest bottleneck that limits its widespread application in clinic. Although deeper biological tissue PDT could be realized through a combination of upconversion nanoparticles with a photosensitizer, issues with particle-size-induced upconversion fluorescence (UF) reduction and the related in vivo toxicity still cannot be solved properly. In this study, we synthesized Y1Rs-ligand [Pro30, Nle31, Bpa32, Leu34]NPY(28-36) (NPY)-modified and photosensitizer MC540-loaded LiLuF4:Yb,Er@nLiGdF4@mSiO2 multifunctional nanocomposites (MNPs) with a core-multishell structure and ultrasmall size. Their in vitro and in vivo breast tumor targeting, trimodality imaging performance, PDT therapeutic efficacy, and acute toxicity were evaluated. Our results demonstrated that the core-multishell MNPs(MC540) could achieve excellent UF imaging, and that doping with Gd3+ and Lu3+ rare earth ions could enhance the MR and CT imaging performance. In addition, the mSiO2 shell provided a higher loading rate for the photosensitizer MC540, and the DSPE-PEG thin layer coating outside the MNPs(MC540) further improved the water solubility and biocompatibility, reducing the acute toxicity of the nanocomposites. Finally, the NPY modification enhanced the targetability of MNPs(MC540)/DSPE-PEG-NPY to breast tumors, improving the trimodality UF, CT, and MR imaging performance and PDT efficacy for Y1-receptor-overexpressed breast cancer. In general, our developed multifunctional nanocomposites can serve as a theranostic agent with low toxicity, providing great potential for their use in clinical breast cancer diagnosis and therapy.

Near-Infrared-Light-Activatable Nanomaterial-Mediated Phototheranostic Nanomedicines: An Emerging Paradigm for Cancer Treatment

Cancer is one of the most deadly diseases threatening the lives of humans. Although many treatment methods have been developed to tackle cancer, each modality of cancer treatment has its own limitations and drawbacks. The development of minimally invasive treatment modalities for cancers remains a great challenge. Near-infrared (NIR) light-activated nanomaterial-mediated phototherapies, including photothermal and photodynamic therapies, provide an alternative means for spatially and temporally controlled minimally invasive treatments of cancers. Nanomaterials can serve as nanocargoes for the delivery of chemo-drugs, diagnostic contrast reagents, and organic photosensitizers, and can be used to directly generate heat or reactive oxygen species for the treatment of tumors without the need for organic photosensitizers with NIR-light irradiation. Here, current progress in NIR-light-activated nanomaterial-mediated photothermal therapy and photodynamic therapy is summarized. Furthermore, the effects of size, shape, and surface functionalities of nanomaterials on intracellular uptake, macrophage clearance, biodistribution, cytotoxicities, and biomedical efficacies are discussed. The use of various types of nanomaterials, such as gold nanoparticles, carbon nanotubes, graphene, and many other inorganic nanostructures, in combination with diagnostic and therapeutic modalities for solid tumors, is briefly reviewed.

A review and outlook in the treatment of osteosarcoma and other deep tumors with photodynamic therapy: from basic to deep

Photodynamic therapy, one of the most promising minimally invasive treatments, has received increasing focus in tumor therapy research, which has been widely applied in treating superficial tumors. Three basic factors - photosensitizer, the light source, and oxidative stress - are responsible for tumor cell cytotoxicity. However, due to insufficient luminous flux and peripheral tissue damage, the utilization of photodynamic therapy is facing a huge limitation in deep tumor therapy. Osteosarcoma is the typical deep tumor, which is the most commonly occurring malignancy in children and adolescents. Despite developments in surgery, high risks of the amputation still threatens the health of osteosarcoma patients. In this review, we summarize recent developments in the field of photodynamic therapy and specifically PDT research in OS treatment modalities. In addition, we also provide some novel suggestions, which could potentially be a breakthrough in PDT-induced OS therapies. PDT has the potential to become an effective therapy while the its limitations still present when applied on the treatment of OS or other types of deep tumors. Thus, more researches and studies in the field are required.

Skin-Attachable, Stretchable Electrochemical Sweat Sensor for Glucose and pH Detection

As part of increased efforts to develop wearable healthcare devices for monitoring and managing physiological and metabolic information, stretchable electrochemical sweat sensors have been investigated. In this study, we report on the fabrication of a stretchable and skin-attachable electrochemical sensor for detecting glucose and pH in sweat. A patterned stretchable electrode was fabricated via layer-by-layer deposition of carbon nanotubes (CNTs) on top of patterned Au nanosheets (AuNS) prepared by filtration onto stretchable substrate. For the detection of glucose and pH, CoWO₄/CNT and polyaniline/CNT nanocomposites were coated onto the CNT-AuNS electrodes, respectively. A reference electrode was prepared via chlorination of silver nanowires. Encapsulation of the stretchable sensor with sticky silbione led to a skin-attachable sweat sensor. Our sensor showed high performance with sensitivities of 10.89 μA mM^-1 cm^-2 and 71.44 mV pH^-1 for glucose and pH, respectively, with mechanical stability up to 30% stretching and air stability for 10 days. The sensor also showed good adhesion even to wet skin, allowing the detection of glucose and pH in sweat from running while being attached onto the skin. This work suggests the application of our stretchable and skin-attachable electrochemical sensor to health management as a high-performance healthcare wearable device.

Monolayer Nanosheets with an Extremely High Drug Loading toward Controlled Delivery and Cancer Theranostics

2D nanomaterials have attracted considerable research interest in drug delivery systems, owing to their intriguing quantum size and surface effect. Herein, Gd³⁺ -doped monolayered-double-hydroxide (MLDH) nanosheets are prepared via a facile bottom-up synthesis method, with a precisely controlled composition and uniform morphology. MLDH nanosheets as drug carrier are demonstrated in coloading of doxorubicin and indocyanine green (DOX&ICG), with an ultrahigh drug loading content (LC) of 797.36% and an encapsulation efficiency (EE) of 99.67%. This is, as far as it is known, the highest LC level at nearly 100% of EE among previously reported 2D drug delivery systems so far. Interestingly, the as-prepared DOX&ICG/MLDH composite material shows both pH-controlled and near-infrared-irradiation-induced DOX release, which holds a promise in stimulated drug release. An in vivo dual-mode imaging, including near-infrared fluorescence and magnetic resonance imaging, enables a noninvasive visualization of distribution profiles at the tumor site. In addition, in vitro and in vivo therapeutic evaluations demonstrate an excellent trimode synergetic anticancer activity and superior biocompatibility of DOX&ICG/MLDH. Therefore, MLDH nanosheets provide new perspectives in the design of multifunctional nanomedicine, which shows promising applications in controlled drug delivery and cancer theranostics.

Zinc phthalocyanine encapsulated in polymer micelles as a potent photosensitizer for the photodynamic therapy of osteosarcoma

Zinc phthalocyanine (ZnPc) is a highly potent second-generation photosensitizer for cancer photodynamic therapy (PDT) with attractive photo-physical and photo-chemical properties. However, poor solubility and strong trend of crystallization prevent it from loading in most of drug delivery systems and hamper its further application. Herein, to overcome this problem, an amphiphilic block copolymer poly(ethylene glycol)-poly[2-(methylacryloyl)ethylnicotinate] (PEG-PMAN) with aromatic nicotinate is used to load ZnPc for their π-π interactions. The formed PEG-PMAN/ZnPc nanoparticle (PPZ) dramatically increases reactive oxygen species production in osteosarcoma cells after light irradiation, causes mitochondrial injury and promotes cell cycle arrest at G2/M, leading to a 100-fold cytotoxicity improvement comparing with free ZnPc. The excellent therapeutic effectiveness and safety of PPZ are also proved by in vivo experiments operating on osteosarcoma model. The finding above indicates that PPZ has promising clinical applications as a next-generation photosensitizer in PDT of osteosarcoma.

Biodegradable MoOx nanoparticles with efficient near-infrared photothermal and photodynamic synergetic cancer therapy at the second biological window

Near-infrared (NIR) laser induced phototherapy has been considered as a noninvasive option for cancer therapy. Herein, we report plasmonic PEGylated molybdenum oxide nanoparticles (PEG-MoO_x NPs) that were synthesized by using a facile hydrothermal method. The PEG-MoO_x NPs exhibit broad absorption at the NIR biological window and remarkable photothermal conversion ability in the first (808 nm) and the second (1064 nm) windows. Moreover, the biocompatible PEG-MoO_x NPs exhibit effective cellular uptake and could be eliminated gradually from the liver and spleen in mice. Studies on the therapeutic effects of these NPs under 808 and 1064 nm exposures with mild hyperthermia are conducted. According to the result, exposure to 1064 nm irradiation can not only effectively convert light into heat but also sensitize the formation of reactive oxygen species (ROS), which exert dramatic cancer cell death and suppression in vivo due to the synergic effect of photothermal therapy (PTT) and photodynamic therapy (PDT). In marked contrast, 808 nm irradiation can only execute limited PTT to cancer cells, showing a relatively low inhibition rate in vitro and in vivo. This biodegradable MoO_x nanoplatform with synergetic PTT and PDT functionalities upon 1064 nm irradiation provided emerging opportunities for the phototherapy of cancer in nanomedicine.

Saline hybrid nanoparticles with phthalocyanine and tetraphenylporphine anions showing efficient singlet-oxygen production and photocatalysis

Gd₄³⁺[AlPCS₄]₃⁴⁻ and La₄³⁺[TPPS₄]₃⁴⁻ ([AlPCS₄]⁴⁻: aluminium(iii) chlorido phthalocyanine tetrasulfonate; [TPPS₄]⁴⁻: tetraphenylporphine sulfonate) inorganic–organic hybrid nanoparticles show efficient ¹O₂ production upon daylight and red-light irradiation.

A metal-semiconductor nanocomposite as an efficient oxygen-independent photosensitizer for photodynamic tumor therapy

Photodynamic therapy (PDT) is regarded as one of the most promising cancer treatments, and oxygen-independent photosensitizers have been intensively explored for advancing the development of PDT. Here, we reported on a superior hybrid nanocomposite (HNC) consisting of a metal (Au deposition) and a semiconductor (CdSe-seeded/CdS nanorods) as a photosensitizer. Under visible light, the photogenerated holes were three-dimensionally confined to the CdSe quantum dots and the delocalized electrons were transferred to the Au tips, which provided hydrogen and oxygen evolution sites for water splitting to generate reactive oxygen species (ROS) with no need for oxygen participation. Compared with semiconductors without deposited metal (i.e. raw CdSe-seeded/CdS nanorods (NRs)) under a normoxic or hypoxic environment, the HNCs exhibited substantially enhanced light-triggered ROS generation in vitro. After being modified with an Arg-Gly-Asp (RGD) peptide sequence, the nanocomposite was deemed as a tumor-targeting, long-lived and oxygen-independent photosensitizer with promoted PDT efficiency for in vivo anti-tumor therapy. This oxygen-independent nanocomposite successfully overcame the hypoxia-related PDT resistance by water splitting, which opened a window to develop conventional semiconductors as photosensitizers for effective PDT.

Dopamine-mediated photothermal theranostics combined with up-conversion platform under near infrared light

An organic-inorganic hybrid core-shell nanostructure, based on mesoporous silica coated upconversion core-shell nanoparticles (NaGdF4:Yb,Er@NaGdF4:Yb@mSiO2-Dopa abbreviated here as UCNP@mSiO2-Dopa) that stably incorporates dopamine (Dopa) in the silica layer was introduced as a theranostic nanoplatform for optical imaging guided photothermal therapy (PTT) using NIR excitation. Silica-attaching polyethylenimine make the Dopa transforms into an active form (transferred Dopa) that strongly absorbs light under single 980 nm irradiation. We show that the activated UCNP@mSiO2-Dopa nanoplatform is able to produce a pronounced photothermal effect, that elevates water temperature from room temperature to 41.8 °C within 2 minutes, while concurrently emitting strong upconverted luminescence (UCL) for visualized guidance under 980 nm laser. In addition, we demonstrate the application of the same UCNP@mSiO2-Dopa nanoplatform for magnetic resonance imaging (MRI) and x-ray computed tomography (CT) enabled by the gadolinium (Gd) element contained in the UCNP. Importantly, the in vitro and in vivo anti-cancer therapeutic effects have been shown efficacious, implying the use of the described nanoplatform as an effective multi-modal imaging enabled PTT agent. Results from the in vivo biodistribution of UCNPs@mSiO2, cellular live/dead assay, and histologic analysis of main organs of treated mice, reveal that the UCNP@mSiO2-Dopa agents are bio-compatible with low toxicity.

Integration of IR-808 Sensitized Upconversion Nanostructure and MoS2 Nanosheet for 808 nm NIR Light Triggered Phototherapy and Bioimaging

Near infrared (NIR) light triggered phototherapy including photothermal therapy (PTT) and photodynamic therapy (PDT) affords superior outcome in cancer treatment. However, the reactive oxygen species (ROS) generated by NIR-excited upconversion nanostructure is limited by the feeble upconverted light which cannot activate PDT agents efficiently. Here, an IR-808 dye sensitized upconversion nanoparticle (UCNP) with a chlorin e6 (Ce6)-functionalized silica layer is developed for PDT agent. The two booster effectors (dye-sensitization and core-shell enhancement) synergistically amplify the upconversion efficiency, therefore achieving superbright visible emission under low 808 nm light excitation. The markedly amplified red light subsequently triggers the photosensitizer (Ce6) to produce large amount of ROS for efficient PDT. After the silica is endowed with positive surface, these PDT nanoparticles can be easily grafted on MoS₂ nanosheet. As the optimal laser wavelength of UCNPs is consistent with that of MoS₂ nanosheet for PTT, the invented nanoplatform generates both abundant ROS and local hyperthermia upon a single 808 nm laser irradiation. Both the in vitro and in vivo assays validate that the innovated nanostructure presents excellent cancer cell inhibition effectiveness by taking advantages of the synergistic PTT and PDT, simultaneously, posing trimodal (upconversion luminescence/computed tomography (CT)/magnetic resonance imaging (MRI) imaging capability.

Cancer Cell Membrane Camouflaged Cascade Bioreactor for Cancer Targeted Starvation and Photodynamic Therapy

Selectively cuting off the nutrient supply and the metabolism pathways of cancer cells would be a promising approach to improve the efficiency of cancer treatment. Here, a cancer targeted cascade bioreactor (designated as mCGP) was constructed for synergistic starvation and photodynamic therapy (PDT) by embedding glucose oxidase (GOx) and catalase in the cancer cell membrane-camouflaged porphyrin metal-organic framework (MOF) of PCN-224 (PCN stands for porous coordination network). Due to biomimetic surface functionalization, the immune escape and homotypic targeting behaviors of mCGP would dramatically enhance its cancer targeting and retention abilities. Once internalized by cancer cells, mCGP was found to promote microenvironmental oxygenation by catalyzing the endogenous hydrogen peroxide (H₂O₂) to produce oxygen (O₂), which would subsequently accelerate the decomposition of intracellular glucose and enhance the production of cytotoxic singlet oxygen (¹O₂) under light irradiation. Consequently, mCGP displayed amplified synergistic therapeutic effects of long-term cancer starvation therapy and robust PDT, which would efficiently inhibit the cancer growth after a single administration. This cascade bioreactor would further facilitate the development of complementary modes for spatiotemporally controlled cancer treatment.

Self-Assembled Carbon Dot Nanosphere: A Robust, Near-Infrared Light-Responsive, and Vein Injectable Photosensitizer

Self-assembly "activated" carbon dot photosensitizer: a robust, NIR-light responsive, and vein injectable carbon dot nanosphere (CDNS) photosensitizer with ¹ O₂ quantum yield of 0.45 under 671 nm laser irradiation has been developed through self-assembly using individual CD as building units. This study develops the biomedical applications of CD, highlights the self-assembly for designing well-defined CD-based photosensitizers, and promotes future explorations of this CDNS photosensitizer in nanomedical and clinical applications.

A Singlet Oxygen Generating Agent by Chirality-dependent Plasmonic Shell-Satellite Nanoassembly

Photodynamic therapy (PDT) agent, which generates singlet oxygen (¹ O₂ ) under light, has attracted significant attention for its broad biological and medical applications. Here, DNA-driven shell-satellite (SS) gold assemblies as chiral photosensitizers are first fabricated. The chiral plasmonic nanostructure, coupling with cysteine enantiomers on its surface, exhibits intense chiroplasmonic activities (-40.2 ± 2.6 mdeg) in the visible region. These chiral SS nanoassemblies have high reactive oxygen species generating efficiency under circular polarized light illumination, resulting in a ¹ O₂ quantum yield of 1.09. Meanwhile, it is found that SS could be utilized as PDT agent with remarkable efficiency under right circular polarized light irradiation in vitro and in vivo, allowing X-ray computed tomography (CT) and photoacoustics (PA) imaging for tumors simultaneously. The achievements reveal that the enantiomer-dependent and structure-induced nanoassemblies play an important role in PDT effects. The present researches open up a new avenue for cancer diagnose and therapy using chiral nanostructures as multifunctional platform.

Highly Emissive Dye-Sensitized Upconversion Nanostructure for Dual-Photosensitizer Photodynamic Therapy and Bioimaging

Rare-earth-based upconversion nanotechnology has recently shown great promise for photodynamic therapy (PDT). However, the NIR-induced PDT is greatly restricted by overheating issues on normal bodies and low yields of reactive oxygen species (ROS, ¹O₂). Here, IR-808-sensitized upconversion nanoparticles (NaGdF₄:Yb,Er@NaGdF₄:Nd,Yb) were combined with mesoporous silica, which has Ce6 (red-light-excited photosensitizer) and MC540 (green-light-excited photosensitizer) loaded inside through covalent bond and electrostatic interaction, respectively. When irradiated by tissue-penetrable 808 nm light, the IR-808 greatly absorb 808 nm photons and then emit a broadband peak which overlaps perfectly with the absorption of Nd³⁺ and Yb³⁺. Thereafter, the Nd³⁺/Yb³⁺ incorporated shell synergistically captures the emitted NIR photons to illuminate NaGdF₄:Yb,Er zone and then radiate ultrabright green and red emissions. The visible emissions simultaneously activate the dual-photosensitizer to produce a large amount of ROS and, importantly, low heating effects. The in vitro and in vivo experiments indicate that the dual-photosensitizer nanostructure has trimodal (UCL/CT/MRI) imaging functions and high anticancer effectiveness, suggesting its potential clinical application as an imaging-guided PDT technique.

Smart Nanostructures for Cargo Delivery: Uncaging and Activating by Light

Nanotechnology has begun to play a remarkable role in various fields of science and technology. In biomedical applications, nanoparticles have opened new horizons, especially for biosensing, targeted delivery of therapeutics, and so forth. Among drug delivery systems (DDSs), smart nanocarriers that respond to specific stimuli in their environment represent a growing field. Nanoplatforms that can be activated by an external application of light can be used for a wide variety of photoactivated therapies, especially light-triggered DDSs, relying on photoisomerization, photo-cross-linking/un-cross-linking, photoreduction, and so forth. In addition, light activation has potential in photodynamic therapy, photothermal therapy, radiotherapy, protected delivery of bioactive moieties, anticancer drug delivery systems, and theranostics (i.e., real-time monitoring and tracking combined with a therapeutic action to different diseases sites and organs). Combinations of these approaches can lead to enhanced and synergistic therapies, employing light as a trigger or for activation. Nonlinear light absorption mechanisms such as two-photon absorption and photon upconversion have been employed in the design of light-responsive DDSs. The integration of a light stimulus into dual/multiresponsive nanocarriers can provide spatiotemporal controlled delivery and release of therapeutic agents, targeted and controlled nanosystems, combined delivery of two or more agents, their on-demand release under specific conditions, and so forth. Overall, light-activated nanomedicines and DDSs are expected to provide more effective therapies against serious diseases such as cancers, inflammation, infections, and cardiovascular disease with reduced side effects and will open new doors toward the treatment of patients worldwide.

Folate-Engineered Microvesicles for Enhanced Target and Synergistic Therapy toward Breast Cancer

As an ideal nanovector candidate, microvesicles (MVs) have been gradually utilized for packaging kinds of functional molecules for effective tumor diagnosis and therapy; however, the deficiency of their tumor targeting influenced their therapy efficacy. Through a facile phospholipid substitution strategy, MVs-based drug delivery system (DDS) was apparently endowed with high tumor targeting toward breast cancer thanks to the modified folate onto the membrane of MVs, simultaneously possessing a synergistic antitumor effect, and in vivo tumor imaging attributed to the SA-QDs labeling. Tumor killing effect could be improved up to 15 percentages with the help of the improved tumor targeting ability.

Black Phosphorus Nanosheet-Based Drug Delivery System for Synergistic Photodynamic/Photothermal/Chemotherapy of Cancer

A black phosphorus (BP)-based drug delivery system for synergistic photodynamic/photothermal/chemotherapy of cancer is constructed. As a 2D nanosheet, BP shows super high drug loading capacity and pH-/photoresponsive drug release. The intrinsic photothermal and photodynamic effects of BP enhance the antitumor activities. The synergistic photodynamic/photothermal/chemotherapy makes BP-based drug delivery system a multifunctional nanomedicine platform.

Novel graphene capsule–aminoporphyrin nanohybrids: preparation and application in photodynamic therapy of cancer

We report on the first preparation of graphene capsule–aminoporphyrin nanohybrids and their application in photodynamic therapy of cancer.

Lanthanide-doped bismuth oxobromide nanosheets for self-activated photodynamic therapy

Low tissue penetration depth of the excited light and complicated synthetic procedures greatly hinder the clinical application of photodynamic therapy (PDT).