Designing of UCNPs@Bi@SiO2 Hybrid Theranostic Nanoplatforms for Simultaneous Multimodal Imaging and Photothermal Therapy

Fluorescent aptasensor for highly sensitive detection of Staphylococcus aureus based on dual-amplification strategy by integrating DNA walking and hybridization chain reaction

Food-borne diseases caused by bacteria threaten human health. Herein, we presented a new fluorescent aptasensor by coupling DNA walking and hybridization chain reaction (HCR) for convenient and sensitive quantification of bacteria. Staphylococcus aureus (S. aureus) was selected as target. When there was target in the system, the binding of S. aureus with its aptamer caused the disintegration of aptamer/DNA walker on the surface of AuNPs and released DNA walker. With the help of Nt.BsmAI, DNA walker moved along the surface of AuNPs and trigger probe was detached from AuNPs. The trigger probe could initiate hybridization chain reaction (HCR) and opened the stems of H1@AuNPs probe and H2@AuNPs probe. After the addition of nicking endonuclease, the adjacent upconversion nanoparticles (UCNPs, NaYF4:Yb3+, Er3+) were further away from the quenchers (AuNPs) of H1 and H2. Therefore, the fluorescence intensity of UCNPs could be restored via fluorescence resonance energy transfer (FRET). Bacteria were thus detected by recording the fluorescence intensity of UCNPs. This method is simple, rapid and sensitive. It can directly detect bacteria in a low background signal. The limit of detection (LOD) was 10 CFU/mL, detection time was less than 3 h. Recovery rates in simulated milk, honey and human serum samples ranged from 93.6 % to 105.8 %. The strategy opens up new paths for early diagnosis of diseases and food monitoring.

Recent progress on bismuth-based light-triggered antibacterial nanocomposites: Synthesis, characterization, optical properties and bactericidal applications

Bacterial infections pose a seriously threat to the safety of the environment and human health. In particular, the emergence of drug-resistant pathogens as a result of antibiotic abuse and high trauma risk has rendered conventional therapeutic techniques insufficient for treating infections by these so-called "superbugs". Therefore, there is an urgent need to develop highly efficient and environmentally-friendly antimicrobial agents. Bismuth-based nanomaterials with unique structures and physicochemical characteristics have attracted considerable attention as promising antimicrobial candidates, with many demonstratingoutstanding antibacterial effects upon being triggered by broad-spectrum light. These nanomaterials have also exhibited satisfactory energy band gaps and electronic density distribution with improved photonic properties for extensive and comprehensive applications after being modified through various engineering methods. This review summarizes the latest research progress made on bismuth-based nanomaterials with different morphologies, structures and compositions as well as the different methods used for their synthesis to meet their rapidly increasing demand, especially for antibacterial applications. Moreover, the future prospects and challenges regarding the application of these nanomaterials are discussed. The aim of this review is to stimulate interest in the development and experimental transformation of novel bismuth-based nanomaterials to expand the arsenal of effective antimicrobials.

Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application

The invention of silica-based bioactive glass in the late 1960s has sparked significant interest in exploring a wide range of silicon-containing biomaterials from the macroscale to the nanoscale. Over the past few decades, these biomaterials have been extensively explored for their potential in diverse biomedical applications, considering their remarkable bioactivity, excellent biocompatibility, facile surface functionalization, controllable synthesis, etc. However, to expedite the clinical translation and the unexpected utilization of silicon-composed nanomedicine and biomaterials, it is highly desirable to achieve a thorough comprehension of their characteristics and biological effects from an overall perspective. In this review, we provide a comprehensive discussion on the state-of-the-art progress of silicon-composed biomaterials, including their classification, characteristics, fabrication methods, and versatile biomedical applications. Additionally, we highlight the multi-dimensional design of both pure and hybrid silicon-composed nanomedicine and biomaterials and their intrinsic biological effects and interactions with biological systems. Their extensive biomedical applications span from drug delivery and bioimaging to therapeutic interventions and regenerative medicine, showcasing the significance of their rational design and fabrication to meet specific requirements and optimize their theranostic performance. Additionally, we offer insights into the future prospects and potential challenges regarding silicon-composed nanomedicine and biomaterials. By shedding light on these exciting research advances, we aspire to foster further progress in the biomedical field and drive the development of innovative silicon-composed nanomedicine and biomaterials with transformative applications in biomedicine.

Near-Infrared-Responsive Rare Earth Nanoparticles for Optical Imaging and Wireless Phototherapy

Near-infrared (NIR) light is well-suited for the optical imaging and wireless phototherapy of malignant diseases because of its deep tissue penetration, low autofluorescence, weak tissue scattering, and non-invasiveness. Rare earth nanoparticles (RENPs) are promising NIR-responsive materials, owing to their excellent physical and chemical properties. The 4f electron subshell of lanthanides, the main group of rare earth elements, has rich energy-level structures. This facilitates broad-spectrum light-to-light conversion and the conversion of light to other forms of energy, such as thermal and chemical energies. In addition, the abundant loadable and modifiable sites on the surface offer favorable conditions for the functional expansion of RENPs. In this review, the authors systematically discuss the main processes and mechanisms underlying the response of RENPs to NIR light and summarize recent advances in their applications in optical imaging, photothermal therapy, photodynamic therapy, photoimmunotherapy, optogenetics, and light-responsive drug release. Finally, the challenges and opportunities for the application of RENPs in optical imaging and wireless phototherapy under NIR activation are considered.

Upconversion nanoparticles@AgBiS2 core-shell nanoparticles with cancer-cell-specific cytotoxicity for combined photothermal and photodynamic therapy of cancers

UCNPs@AgBiS₂ core-shell nanoparticles that AgBiS₂ coated on the surface of upconversion nanoparticles (UCNPs) was successfully prepared through an ion exchange reaction. The photothermal conversion efficiency of AgBiS₂ can be improved from 14.7% to 45% due to the cross relaxation between Nd ions and AgBiS₂. The doping concentration of Nd ions played a critical role in the production of reactive oxygen species (ROS) and enhanced the photothermal conversion efficiency. The NaYF₄:Yb/Er/Nd@NaYF₄:Nd nanoparticles endows strong upconversion emissions when the doped concentration of Nd ions is 1% in the inner core, which excites the AgBiS₂ shell to produce ROS for photodynamic therapy (PDT) of cancer cells. As a result, the as-prepared NaYF₄:Yb/Er/Nd@NaYF₄:Nd@AgBiS₂ core-shell nanoparticles showed combined photothermal/photodynamic therapy (PTT/PDT) against malignant tumors. This work provides an alternative near-infrared light-active multimodal nanostructures for applications such as fighting against cancers.

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UCNPs@AgBiS₂ core-shell nanoparticles firstly prepared via a facile chemical process.

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The photothermal conversion efficiency for UCNPs@AgBiS₂ core-shell nanoparticles reached up to 45%.

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The as-prepared UCNPs@AgBiS₂ core-shell nanoparticles showed superoroir therapeutic efficacy for cancers.

Nanocomposites based on lanthanide-doped upconversion nanoparticles: diverse designs and applications

Lanthanide-doped upconversion nanoparticles (UCNPs) have aroused extraordinary interest due to the unique physical and chemical properties. Combining UCNPs with other functional materials to construct nanocomposites and achieve synergistic effect abound recently, and the resulting nanocomposites have shown great potentials in various fields based on the specific design and components. This review presents a summary of diverse designs and synthesis strategies of UCNPs-based nanocomposites, including self-assembly, in-situ growth and epitaxial growth, as well as the emerging applications in bioimaging, cancer treatments, anti-counterfeiting, and photocatalytic fields. We then discuss the challenges, opportunities, and development tendency for developing UCNPs-based nanocomposites.

On-Demand Triggered Chemodynamic Therapy by NIR-II Light on Oxidation-Prevented Bismuth Nanodots

As the least toxic heavy metal, monoelemental bismuth nanomaterials with several superiorities are the ideal theranostic agents. However, bismuth nanoparticles are easily oxidized by oxygen in air or media, limiting their clinical application. In contrast, the oxidization of Bi⁰ to Bi³⁺ can activate the chemodynamic therapy (CDT) by transferring endogenous H₂O₂ into ^•OH. Herein, a well-designed Bi-DMSNs@PCM nanosystem was prepared via in situ growth of Bi nanodots and a coating of phase-change material (PCM) on the surface of dendritic mesoporous silica nanoparticles (DMSNs). The coated PCM protects the Bi nanodots from oxidation by keeping them in the Bi⁰ state for more than 15 d. When irradiated using the near infrared-II (NIR-II) laser with a low power density (0.5 W/cm²), the heat generated from the Bi nanodots melts the PCM shell to trigger CDT through a Fenton-like reaction, accompanied by heat-induced photothermal therapy (PTT). Notably, the CDT can also compensate for the reduced PTT effect caused by the oxidation of Bi nanodots, and a satisfactory treatment effect is realized. Additionally, photoacoustic and computed tomography imaging properties were obtained. Our strategy transfers the detrimental self-oxidation of bismuth to a beneficial therapeutic mode, enhancing the potential of Bi for clinical use.

Fibronectin-Coated Metal-Phenolic Networks for Cooperative Tumor Chemo-/Chemodynamic/Immune Therapy via Enhanced Ferroptosis-Mediated Immunogenic Cell Death

The development of nanomedicine formulations to overcome the disadvantages of traditional chemotherapeutic drugs and integrate cooperative theranostic modes still remains challenging. Herein, we report the facile construction of a multifunctional theranostic nanoplatform based on doxorubicin (DOX)-loaded tannic acid (TA)-iron (Fe) networks (for short, TAF) coated with fibronectin (FN) for combination tumor chemo-/chemodynamic/immune therapy under the guidance of magnetic resonance (MR) imaging. We show that the DOX-TAF@FN nanocomplexes created through in situ coordination of TA and Fe(III) and physical coating with FN have a mean particle size of 45.0 nm, are stable, and can release both DOX and Fe in a pH-dependent manner. Due to the coexistence of the TAF network and DOX, significant immunogenic cell death can be caused through enhanced ferroptosis of cancer cells via cooperative Fe-based chemodynamic therapy and DOX chemotherapy. Through further treatment with programmed cell death ligand 1 antibody for an immune checkpoint blockade, the tumor treatment efficacy and the associated immune response can be further enhanced. Meanwhile, with FN-mediated targeting, the DOX-TAF@FN platform can specifically target tumor cells with high expression of α_vβ₃ integrin. Finally, the TAF network also enables the DOX-TAF@FN to have an r₁ relaxivity of 6.1 mM^-1 s^-1 for T₁-weighted MR imaging of tumors. The developed DOX-TAF@FN nanocomplexes may represent an updated multifunctional nanosystem with simple compositions for cooperative MR imaging-guided targeted chemo-/chemodynamic/immune therapy of tumors.

An outstanding role of novel virus-like heterojunction nanosphere BOCO@Ag as high performance antibacterial activity agent

The development of highly efficient photonic nanomaterials with synergistic biological effects is critical and challenging task for public hygiene health well-being and has attracted extensive interest. In this study, a type of near-infrared (NIR) driven, virus-like heterojunction was first developed for synergistic biological application. The Ag-coated Bi₂CO₅ nanomaterial (BOCO@Ag) demonstrated good biocompatibility, low cytotoxicity, high antibacterial activity and excellent light utilization stability. The synthesized BOCO@Ag performed a potential high photothermal conversion (efficiency~46.81%) to generate high temperatures when irradiated with near-infrared light illumination. As expected, compared to single Ag+ disinfection, BOCO@Ag can exhibit better antibacterial performance when combined with photothermal energy and released Ag+ . These results suggest that BOCO@Ag can be a promising photo-activate antimicrobial candidate and provide security for humans health and the environment treatment.

Selenium Vacancy Engineering Using Bi2Se3 Nanodots for Boosting Highly Efficient Photonic Hyperthermia

Despite bismuth-based energy conversion nanomaterials having attracted extensive attention for nanomedicine, the nanomaterials suffer from major shortcomings including low tumor accumulation, long internal retention time, and undesirable photothermal conversion efficiency (PCE). To combat these challenges, bovine serum albumin and folic acid co-modified Bi2Se3 nanomedicine with rich selenium vacancies (abbreviated as VSe-BS) was fabricated for the second near-infrared (NIR-II) light-triggered photonic hyperthermia. More importantly, selenium vacancies on the crystal planes (0 1 5) and (0 1 11) of VSe-BS with similar formation energies could be distinctively observed via aberration-corrected scanning transmission electron microscopy images. The defect engineering endows VSe-BS with enhanced conductivity, making VSe-BS possess outstanding PCE (54.1%) in the NIR-II biowindow and desirable photoacoustic imaging performance. Tumor ablation studies indicate that VSe-BS possesses satisfactory therapeutic outcomes triggered by NIR-II light. These findings give rise to inspiration for further broadening the biological applications of defect engineering bismuth-based nanomaterials.

How do bismuth-based nanomaterials function as promising theranostic agents for the tumor diagnosis and therapy?

The complexity of tumor microenvironment and the diversity of tumors seriously affect the therapeutic effect, the focus, therefore, has gradually been shifted from monotherapy to combination therapy in clinical research in order to improve the curative effect. The synergistic enhancement interactions among multiple monotherapies majorly contribute to the birth of the multi-mode cooperative therapy, whose effect of the treatment is clearly stronger than that of any single therapy. In addition, the accurate diagnosis of the tumour location is also crucial to the treatment. Bismuth-based nanomaterials (NMs) hold great properties as promising theranostic platforms based on their many unique features that include low toxicity, excellent photothermal conversion efficiency as well as high ability of X-ray computed tomography imaging and photoacoustic imaging. In this review, we will introduce briefly the main features of tumor microenvironment first and its effect on the mechanism of nanomedicine actions and present the recent advances of bismuth-based NMs for diagnosis and photothermal therapy-based combined therapies using bismuth-based NMs are presented, which may provide a new way for overcoming drug resistance and hypoxia. At the end, further challenges and outlooks regarding this promising field are discussed accompanied with some design tips for bismuth-based NMs, hoping to provide researchers some inspirations to design safe and effective nanotherapeutic agents for the clinical treatments of cancers.

Lanthanide ion (Ln3+ )-based upconversion sensor for quantification of food contaminants: A review

The food safety issue has gradually become the focus of attention in modern society. The presence of food contaminants poses a threat to human health and there are a number of interesting researches on the detection of food contaminants. Upconversion nanoparticles (UCNPs) are superior to other fluorescence materials, considering the benefits of large anti-Stokes shifts, high chemical stability, non-autofluorescence, good light penetration ability, and low toxicity. These properties render UCNPs promising candidates as luminescent labels in biodetection, which provides opportunities as a sensitive, accurate, and rapid detection method. This paper intended to review the research progress of food contaminants detection by UCNPs-based sensors. We have proposed the key criteria for UCNPs in the detection of food contaminants. Additionally, it highlighted the construction process of the UCNPs-based sensors, which includes the synthesis and modification of UCNPs, selection of the recognition elements, and consideration of the detection principle. Moreover, six kinds of food contaminants detected by UCNPs technology in the past 5 years have been summarized and discussed fairly. Last but not least, it is outlined that UCNPs have great potential to be applied in food safety detection and threw new insight into the challenges ahead.

Mannose modified zwitterionic polyester-conjugated second near-infrared organic fluorophore for targeted photothermal therapy

Cancer resistance has been the huge challenge to clinical treatment. A photothermal therapy of second near-infrared (NIR-II) organic dye small molecule has been used to conquer the cancer resistance. However, the available NIR-II dye lacks selectivity and spreads throughout the body. It has toxicity and indiscriminate burn injuries normal cells and tissues during therapy. Hence, to improve the therapeutic outcomes, herein, for the first time, we report the mannose-modified zwitterionic nanoparticles loading IR1048 dye, aiming to overcome cancer cellular resistance. The targeting molecule mannose has been applied to modify zwitterionic polyester, and the obtained polyester is employed to load IR1048 to prolong the circulation time in the blood and improve the stability of loaded dye, due to the good cytocompatibility of polyester and the antifouling properties of zwitterions. In vitro experimental results show that the pH-responsive targeted nanoparticles display satisfactory photophysical properties, prominent photothermal conversion efficiency (44.07%), excellent photothermal stability, negligible cytotoxicity for normal cells and strong photothermal toxicity to drug-resistant cancer cells. Moreover, due to the mannose targeting effect, cancer cells can endocytose the nanoparticles effectively. All these results demonstrate potential application of this alternative hyperthermal delivery system with remote-controllable photothermal therapy of tumor for accurate diagnosis by NIR-II fluorescence imaging.

Magnetic-gold theranostic nanoagent used for targeting quad modalities T 1 & T 2-MRI/CT/PA imaging and photothermal therapy of tumours

We describe a new type of ultra-small magneto-gold nanoparticle (MGN) with folic acid (FA)-based tumour targeting and multimodal imaging-guided photothermal therapy (PTT) properties that can be used as a theranostic nanoagent. The nanoagent integrates these MGNs–FA with surface modifications, and as expected, is monodisperse, and exhibits small size, strong NIR absorption, photothermal stability, good relaxivity and X-ray absorption coefficient, tumour targeting and excellent biocompatibility. Based on these properties, the nanoagent was successfully tested, both as a photothermal agent for high PTT efficacy and as a multimodality contrast agent for T₁- & T₂-MRI/CT/PA imaging in vitro and in vivo. Notably, the results of in vivo theranostic experiments with these MGNs–FA showed that they are highly effective and safe, indicating that they are efficient and promising theranostic agents that permit comprehensive imaging for diagnosis and therapy.

The schematic diagram of the biofunctionalized magneto-gold nanoparticles as theranostic nanoagents for T₁ & T₂-MRI/CT/PAI quad modalities imaging and PTT therapy of tumours.

Upconversion nanoparticles modified by Cu2S for photothermal therapy along with real-time optical thermometry

Highly effective photothermal conversion performance coupled with high resolution temperature detection in real time is urgently needed for photothermal therapy (PTT). Herein, ultra-small Cu₂S nanoparticles (NPs) were designed to absorb on the surface of NaScF₄: Yb³⁺/Er³⁺/Mn²⁺@NaScF₄@SiO₂ NPs to form a central-satellite system, in which the Cu₂S NPs play the role of providing significant light-to-heat conversion ability and the Er³⁺ ions in the NaScF₄: Yb³⁺/Er³⁺/Mn²⁺ cores act as a thermometric probe based on the fluorescence intensity ratio (FIR) technology operating in the biological windows. A wavelength of 915 nm is used instead of the conventional 980 nm excitation wavelength to eliminate the laser induced overheating effect for the bio-tissues, by which Yb³⁺ can also be effectively excited. The temperature resolution of the FIR-based optical thermometer is determined to be better than 0.08 K over the biophysical temperature range with a minimal value of 0.06 K at 298 K, perfectly satisfying the requirements of biomedicine. Under the radiation of 915 nm light, the Cu₂S NPs exhibit remarkable light-to-heat conversion capacity, which is proved by photothermal ablation testing of E. coli. The results reveal the enormous potential of the present NPs for PTT integrated with real-time temperature sensing with high resolution.

Imaging-guided nanomedicine development

Nanomedicine research is an active field that produces thousands of studies every year. However, translation of nanotherapeutics to the clinic has yet to catch up with such a vast output. In recent years, the need to better understand nanomedicines' in vivo behavior has been identified as one of the major challenges for efficient clinical translation. In this context, noninvasive imaging offers attractive solutions to provide valuable information about nanomedicine biodistribution, pharmacokinetics, stability, or therapeutic efficacy. Here, we review the latest imaging approaches used in the development of therapeutic nanomedicines, discuss why these strategies bring added value along the translational pipeline, and give a perspective on future advances in the field.

Hetero-Core-Shell BiNS-Fe@Fe as a Potential Theranostic Nanoplatform for Multimodal Imaging-Guided Simultaneous Photothermal-Photodynamic and Chemodynamic Treatment

Photothermal/photodynamic therapy (PTT/PDT) and synergistic therapeutic strategies are often sought after, owing to their low side effects and minimal invasiveness compared to chemotherapy and surgical treatments. However, in spite of the development of the most PTT/PDT materials with good tumor-inhibitory effect, there are some disadvantages of photosensitizers and photothermal agents, such as low stability and low photonic efficiency, which greatly limit their further application. Therefore, in this study, a novel bismuth-based hetero-core-shell semiconductor nanomaterial BiNS-Fe@Fe with good photonic stability and synergistic theranostic functions was designed. On the one hand, BiNS-Fe@Fe with a high atomic number exhibits good X-ray absorption, enhanced magnetic resonance (MR) T₂-weighted imaging, and strong photoacoustic imaging (PAI) signals. In addition, the hetero-core-shell provides a strong barrier to decline the recombination of electron-hole pairs, inducing the generation of a large amount of reactive oxygen species (ROS) when irradiated with visible-NIR light. Meanwhile, a Fenton reaction can further increase ROS generation in the tumor microenvironment. Furthermore, an outstanding chemodynamic therapeutic potential was determined for this material. In particular, a high photothermal conversion efficiency (η = 37.9%) is of significance and could be achieved by manipulating surface decoration with Fe, which results in tumor ablation. In summary, BiNS-Fe@Fe could achieve remarkable utilization of ROS, high photothermal conversion law, and good chemodynamic activity, which highlight the multimodal theranostic potential strategies of tumors, providing a potential viewpoint for theranostic applications of tumors.

Pnictogen Semimetal (Sb, Bi)-Based Nanomaterials for Cancer Imaging and Therapy: A Materials Perspective

Innovative multifunctional nanomaterials have attracted tremendous interest in current research by facilitating simultaneous cancer imaging and therapy. Among them, antimony (Sb)- and bismuth (Bi)-based nanoparticles are important species with multifunction to boost cancer theranostic efficacy. Despite the rapid development, the extensive previous work treated Sb- and Bi-based nanoparticles as mutually independent species, and therefore a thorough understanding of their relationship in cancer theranostics was lacking. We propose here that the identical chemical nature of Sb and Bi, being semimetals, provides their derived nanoparticles with inherent multifunction for near-infrared laser-driven and/or X-ray-based cancer imaging and therapy as well as some other imparted functions. An overview of recent progress on Sb- and Bi-based nanoparticles for cancer theranostics is provided to highlight the relationship between chemical nature and multifunction. The understanding of Sb- and Bi-based nanoparticles in this way might shed light on the further design of smart multifunctional nanoparticles for cancer theranostics.

"One stone, two birds": engineering 2-D ultrathin heterostructure nanosheet BiNS@NaLnF4 for dual-modal computed tomography/magnetic resonance imaging guided, photonic synergetic theranostics

It is interesting yet challenging to design theranostic nanoplatforms for the accurate diagnosis and therapy of diseases; these nanoplatforms consist of single contrast-enhanced imaging or therapeutic agents, and they possess their own unique shortcomings that limit their widespread bio-medical applications. Therefore, designing a potential theranostic agent is an emerging approach for the synergistic diagnosis and therapeutics in bio-medical applications. Herein, a lanthanide-loaded (NaLnF₄) heterostructure BiOCl ultrathin nanosheet (BiNS@NaLnF₄) as a theranostic agent was synthesized facilely by a solvothermal protocol. BiNS@NaLnF₄ was employed as a multi-modal contrast agent for computed tomography (CT) and magnetic resonance imaging (MRI), showing a high-performance X-ray absorption contrast effect, an outstanding T₁-weighted imaging function result, good cytocompatibility and favorable in vivo effective imaging for CT. Notably, BiNS@NaLnF₄ was applied to achieve a satisfactory photon-thermal conversion efficiency (35.3%). Moreover, the special heterostructure barrier achieved increased utilization of electrons/holes, enhancing the generation of reactive oxygen species (ROS) under visible-light irradiation to further expand the therapeutic effect. Dramatically, visible light emission with the up-conversion law was employed to stimulate ROS after irradiation with a 980 nm laser. Simultaneously, the as-prepared BiNS@NaLnF₄ can be applied in photothermal/photodynamic therapy (PTT/PDT) investigation for tumor ablation. In summary, the results reveal that BiNS@NaLnF₄ is a potential multi-modal theranostic candidate, providing new insights for synergistic theranostics of tumors.

NIR-triggered upconversion nanoparticles@thermo-sensitive liposome hybrid theranostic nanoplatform for controlled drug delivery

A novel hybrid photothermal theranostic nanoplatform UCNPs@Bi@SiO2@GE HP-lips is developed. Upon NIR irradiation, the nanoplatform could photothermally trigger controlled drug release and present bright upconversion luminescence.

Engineering Cu2−xS-conjugated upconverting nanocomposites for NIR-II light-induced enhanced chemodynamic/photothermal therapy of cancer

Cu2−xS-conjugated upconverting nanocomposites with an outstanding photothermal killing effect and a PT-enhanced CDT effect for NIR-II light-induced enhanced chemodynamic/photothermal therapy of cancer.

Use of the Highly Biocompatible Au Nanocages@PEG Nanoparticles as a New Contrast Agent for In Vivo Computed Tomography Scan Imaging

In recent years, contrast agents have been widely used in imaging technology to improve quality. Nanoparticles have better in vivo detection capability than conventional molecular scale contrast agents. In this study, a new type of Au nanocages@PEG nanoparticles (AuNC@PEGs) with a strong X-ray absorption coefficient was synthesized as a contrast agent for computed tomography (CT) scan imaging. Results showed that AuNC@PEGs had good aqueous dispensation, low cytotoxicity, and strong X-ray absorption ability. Furthermore, in vivo studies have shown that the synthesized AuNC@PEGs have an evident contrast enhancement, long circulation time in the blood, and negligible toxicity in vivo. Therefore, the synthesized functionalized AuNC@PEGs in this study have great potential for clinical application in CT scan imaging.

Decoration of upconversion nanocrystals with metal sulfide quantum dots by a universal in situ controlled growth strategy

Conjugating transition-metal sulfide quantum dots and upconversion nanocrystals (UCNCs) has aroused widespread concern due to enhanced physical and chemical properties in contrast to only their simple sum. However, the synthesis of such hybrid nanoparticles by a universal in situ growth strategy has been scarcely reported so far. Herein, we developed a facile approach to functionalize NaYF₄:Yb/Er with chitosan (NaYF₄:Yb/Er@CS), which not only could improve the hydrophilicity of NaYF₄:Yb/Er, but also can form stable chelates with transition-metal ions. Then, ultrasmall metal sulfide (Mⁿ⁺S, M = Ag, Cu, Cd) quantum dots (QDs) can be conjugated homogeneously on the surface of NaYF₄:Yb/Er@CS. Taking Ag₂S as an example, the growth behavior of Ag₂S QDs on the surface of NaYF₄:Yb/Er@CS was studied specifically. The influence of the Ag : Y ratio, S : Ag ratio, pH value, reaction time and reaction temperature on the growth behavior of Ag₂S on the surface of NaYF₄:Yb/Er@CS was investigated systematically. Meanwhile, this innovative strategy is also suitable for the growth of ultrasmall QDs in various shapes, including plates, spheres and rods. The resultant NaYF₄:Yb/Er@CS@Ag₂S system possesses both upconversion luminescence (UCL) properties of NaYF₄:Yb/Er and a good photothermal conversion effect of Ag₂S, and is a promising candidate for UCL imaging guided PTT of cancer.

Fabrication of NaYF4:Yb3+,Tm3+-modified Ag nanocubes with upconversion luminescence and photothermal conversion properties

Herein, uniform Ag nanocube@NaYF₄:Yb³⁺,Tm³⁺ multifunctional nanocomposites were constructed by a facile synthetic strategy. Following the successful synthesis of Ag nanocubes, cubic phase NaYF₄:Yb³⁺,Tm³⁺ upconversion luminescent nanocrystals were modified on the surface of the Ag nanocubes, enhanced the mutual assistance of energy and versatility of the materials. Upon irradiation with a near-infrared laser, the nanocomposites exhibited excellent upconversion fluorescence and good photothermal conversion capability. Furthermore, the potential biological applications and biosafety of the Ag@NaYF₄:Yb³⁺,Tm³⁺ nanocomposites were also demonstrated; the obtained nanocomposites could achieve a good bactericidal performance and photothermal treatment of cancer cells, and they could be potentially applied in the biomedical field as a promising agent. Furthermore, this method provides a facile approach for synthesizing a multifunctional nanocomposite with different properties.

Ag nanocubes@NaYF₄:Yb³⁺,Tm³⁺ multifunctional nanocomposites with florescence and photothermal ability are fabricated by a facile strategy, which enhance the mutual assistance of energy and biological application.

A redox-activated theranostic nanoplatform: toward glutathione-response imaging guided enhanced-photodynamic therapy

A redox-sensitive nanoagent (DCMn-RA) for dual-mode GSH detection, NIR-II imaging and enhanced PDT is described.