Search

Near-infrared (NIR)-activable liposomes containing photosensitizer (PS)-lipid conjugates are emerging as tunable, high-payload, and tumor-selective platforms for photodynamic therapy (PDT)-based theranostics. To date, the impact that the membrane composition of a NIR-activable liposome (the chemical nature and subsequent conformation of PS-lipid conjugates) has on their in vitro and in vivo functionality has not been fully investigated. While their chemical nature is critical, the resultant physical conformation dictates their interactions with the immediate biological environments. Here, we evaluate NIR-activable liposomes containing lipid conjugates of the clinically-used PSs benzoporphyrin derivative (BPD; hydrophobic, membrane-inserting conformation) or IRDye 700DX (hydrophilic, membrane-protruding conformation) and demonstrate that membrane composition is critical for their function as tumor-selective PDT-based platforms. The PS-lipid conformations were primarily dictated by the varying solubilities of the two PSs and assisted by their lipid conjugation sites. Conformation was further validated by photophysical analysis and computational predictions of PS membrane partitioning (topological polar surface area [tPSA], calculated octanol/water partition [cLogP], and apparent biomembrane permeability coefficient [Papp]). Results show that the membrane-protruding lipo-IRDye700DX exhibits 5-fold more efficient photodynamic generation of reactive molecular species (RMS), 12-fold expedited phototriggered burst release of entrap-ped agents, and 15-fold brighter fluorescence intensity as compared to the membrane-inserting lipo-BPD-PC (phosphatidylcholine conjugate). Although the membrane-inserting lipo-BPD-PC exhibits less efficient photo-dynamic generation of RMS, it allows for more sustained phototriggered release, 10-fold greater FaDu cancer cell phototoxicity, and 7.16-fold higher tumor-selective delivery in orthotopic mouse FaDu head and neck tumors. These critical insights pave the path for the rational design of emerging NIR-activable liposomes, whereby functional consequences of membrane composition can be tailored toward a specific therapeutic purpose.

Multifunctional magnetic nanoparticles (NPs) that can generate and monitor heat (in real-time) during thermal therapy are a major challenge in nanomedicine. Here, we report a trimodal system combin...

We report the microwave-assisted synthesis of binary doped optical-magnetic up/downconverting NaGdF4:RE and iron oxide/SiO2/NaGdF4:RE nanoparticles. The morphological characteristics were finely tuned from elongated rod-shaped to ovoidal nanoparticles. The (Yb, and Er) activated particles provided an excellent up/down conversion luminescence emission in the green and mid-infrared region under excitation of 980 nm, whereas the (Ce, and Eu) activated systems exhibited a strong red emission via the Gd3+ sublattice upon excitation in the UV region. The magnetic hysteresis at 300 K for β-NaGdF4:RE showed typical signatures of a paramagnetic system, whereas iron oxide/SiO2/β-NaGdF4:RE exhibited superparamagnetic behavior along with a Curie-like component. The luminescence quenching effects induced by the presence of iron oxide phase have been validated through comparing the emission/lifetime decay curves. In addition to the excellent optical and magnetic properties, these materials show remarkably high longitudal and transverse relaxivity values (for Fe and Gd) and thus are potential candidates for T1 and T2-weighted bioimaging.

To investigate the role of magnetic anisotropy on magnetic hyperthermia heating efficiency at low field conditions, Mn, MnZn, and MnCo-ferrite nanoparticles were synthesized using the hydrothermal method. The coercive field temperature dependence method was used to determine the blocking temperature distribution of the particles by considering the temperature dependence of anisotropy and magnetization and the random anisotropy axis configuration. The data allowed one to estimate the room-temperature quasi-static superparamagnetic diameter, which was found to be lower than the theoretical value. Magnetic hyperthermia experiments of the magnetic nanocolloids at 522 kHz indicated that soft nanomagnets heat more efficiently at clinically relevant conditions. The heating performance was found to decrease at the higher fraction of blocked nanoparticles. For instance, samples with similar size distribution and mean diameter of 10 nm, at a field amplitude of only 120 Oe (9.6 kA m–1), showed a decrease of specific...

The design of novel materials is a fundamental focal point of material science research. Nanomaterials less than 100 nm in size have attracted significant interest over several decades due to their unique properties led by surface effect and finite size effect. Colloidal chemistry plays a key role in the controlled production of different classes of nanoparticles, thus being a subject of growing interest in several fields of materials, inorganic, physical chemistry, biophysics, and biomedical. Therefore, in this chapter, we sought to present an introductory outline of liquid-phase synthesis, nucleation, and growth mechanism of nanomaterials focusing on the magnetic nanoparticles. As per the broadness of this book, special attention was devoted to nanoparticles based on iron oxide and rare earth compounds, due to their rapid flourishing importance in biomedical field. Therefore, the work presents ideas involved in the most commonly applied methodologies for the liquid-phase synthesis of nanoparticles, such as co-precipitations and hydro/solvothermal techniques, as well as precipitations into nanoreactors based on reverse microemulsions, with a brief survey of the main advances in these fields in recent years. We have thoroughly presented the synthesis routes of several hybrid nanostructures such as magnetic silica/carbon, magnetic luminescence, magneto-plasmonics, and others. At last, the importance of surface modification and further bio-conjugation has been discussed.

Inorganic nanomaterials have been extensively investigated for several biological applications ranging from targeted drug delivery to cancer treatment and tissue engineering to in vivo imaging. Gold and iron oxide nanoparticles (IONPs) are important candidate of inorganic nanomaterials considering their non-toxic nature and relevant magnetic and optical properties. Most of the biomedical applications involve detailed tuning of surface charge and physiochemical properties. Understanding of pharmacokinetics of these nanoparticles is very important to elaborate on the distribution and fate in the living organism. Many factors including size distribution, charge, and plasma protein adsorption; coating molecules can tune effectively to monitor the biodistribution and pharmacokinetics of the gold- and iron oxide-based nanoparticles. This chapter reviews the crucial parameters that affect the biodistribution, fate, and toxicity of the inorganic nanoparticles in the biological systems.

The present chapter gives an overview of third-generation solar cells with special emphasize on important synthesis protocol for ZnO, TiO2, and rare earth-based upconverting materials for their utilization in the field of solar cells. Moreover, we have discussed working principle and basic requirements for organic-based solar cells, which is in major focus of research worldwide. This is booming research field and has enormous scope to serve humankind to combat energy scarcity and futuristic application for harvesting the solar energy.

In the present chapter, we have reviewed the possibility of LaMnO3 and Sr-doped perovskite manganites LaMnO3 (LMO) nanomaterials in therapeutics and diagnostics with a special attention for hyperthermia applications. In addition, we have also emphasized on the importance of synthesis, heating mechanism, concept of self-regulated hyperthermia, and toxicity issue of this important class of nanomaterials for their safer use in biological applications.

Magnetic particle hyperthermia is potentially the most significant and promising methods for cancer treatment. The high efficiency of this magnetic hyperthermia therapy is derived from a capability of nano-heterostructures to generate site-specific heating of tumors tissues due to their unique physicochemical properties with an ability to be functionalized at molecular and cellular level for biochemical interactions. Au-Fe3O4 nano-heterostructures are gaining ample significance in industry and research because of their superior properties coming from both individual and combinational features of gold and iron oxide nanoparticles. In this chapter, we have discussed the heat dissipation mechanisms and various parameters crucial for assessing the hyperthermia efficacy of gold-iron oxide and noble metal-ferrite systems.

Recent time has witnessed a progressive growth in the fabrication multifunctional upconversion-magnetic hybrid nanostructured materials due to their important applications. The magnetic-luminescent hybrid nanostructures, which combine luminescent nanoparticles with magnetic nanoentities, exhibit potentials for enhanced bioimaging, controlled drug delivery, and enhanced thermal therapy. Such nanoparticles have potential to have simultaneous systematic use of theranostics and drug delivery and could lead to new opportunities in nanobiomedicines. In the present chapter, we have discussed an important class of magnetic-luminescent nanomaterials for their application in theranostic and drug delivery.

Green emitting iron-oxide@NaGdF4:RE3+ (RE = 5%Ce, 5%Tb, 5%Dy) nanoparticles have been synthesized using microwave assisted solvothermal method. The Rietveld analysis of powder X-ray diffraction and high-resolution transmission electron microscopy provides an average crystallite size (∼20 nm) and the hexagonal crystal structure. Magnetic hysteresis loops at 300 K display superparamagnetic behavior along with paramagnetic feature for the reference NaGdF4:RE3+, further validated through magnetization versus temperature curves taken in an external magnetic field of 100 Oe. The photoluminescence investigation of the nanoparticles, suggest a down-converting energy transfer. The excitation spectra consist of a dominant broad band at around 254 nm due to Ce3+(4f–5d) along with f-f transitions due to Gd3+, Tb3+ and Dy3+ ions. The strong emission color lines due to characteristic transitions of Tb3+ (5D4 → 7FJ, J = 6–3), and Dy3+ (4F9/2–6H15/2, 6H13/2), were observed. The luminescence quenching in iron-oxide/NaGdF4:RE3+ through leakage path provided by iron-oxide to excite electrons has been confirmed and explained by comparing the time decay analysis.

The preparation of novel triply-doped bifunctional Fe3O4/ZnS@LaF3:xCe3+,xGd3+,yTb3+ (x = 5; y = 5, 10 and 15 mol%) nanocomposites with efficient optical and magnetic features has been reported. The ZnS semiconductor functionalized Fe3O4 particles were coated with LaF3:RE3+ materials via a chitosan-assisted co-precipitation method. The size of iron oxide ∼7.2 nm and trigonal structures of bifunctional nanostructures were confirmed through X-ray diffraction and high-resolution transmission electron microscopy. The static magnetic measurements supported and manifested the superparamagnetic behavior of the materials at 300 K. A broad emission band was observed in the blue region (400–550 nm) due to the sulphur vacancy on the surface of the Fe3O4/ZnS nanocomposite. For a triply doped bifunctional nanostructure, the excitation spectra revealed broad absorption bands centered at around 270 nm, which were attributed to the 4f(7F7/2) → 5d interconfigurational transition of the Ce3+ ion accompanied by narrow absorption lines arising from the 4f–4f intraconfigurational transitions of the Tb3+ ion. The emission spectra of the nanocomposites showed characteristic narrow emission lines assigned to the 5D4 → 7FJ transitions (J = 6–0) of the Tb3+ ion. The energy transfer process from the Ce3+ → Gd3+ → Tb3+ ions has also been presented and discussed. Furthermore, the structural, photoluminescence and magnetic properties of Fe3O4/ZnS@LaF3:RE3+ suggested that it may be an efficient candidate for magnetic light-converting molecular devices (MLMCDs) and high energy radiation detection.

Nanoscience provides several modalities to combat cancer disease effectively. Magnetic hyperthermia and photothermal therapy techniques are central research themes among various groups in the world by utilizing magnetic and optical characteristics of distinct or composite nanoentities. This review provides the current research on both the techniques and their successes towards clinical translation. This review discusses about the various heating mechanisms involved in magnetic and photo-induced hyperthermia. We have evaluated potential functional nanoparticles with excellent properties capable of providing innovative future solutions to current problems associated with these therapies. Several factors (extracellular and intracellular) have been covered and explained which may affect such thermal treatments. We have provided some instrumental and technical details of both the techniques that are important for consideration in using these modalities of treatments. A direct comparison of these two techniques and a further need of the combined therapy (magnetic hyperthermia plus photothermal therapy) was highlighted as a new pathway for cancer treatments.

The promises of magnetic nanomaterials are huge, and to achieve the grand challenges in the field of nanomagnetism, it is necessary to understand magnetism at nanoscale. The fundamental characteristic of the same material differs greatly at nanoscale and macroscale. The reason is broken translation symmetry at nanoscale, along with the sizes of nano-objects proportionate to characteristic lengths of the inherent material, and some other effects. In this chapter, an overview of the fundamentals of magnetism at nanoscale, with emphasis on explaining the mechanism underlying various phenomenon at nanolevel, is provided. Special attention has been paid to the origin of magnetic domains, exchange bias, and role of different anisotropies in nanomagnetism, as they have become a key issue in current research. An insight to the exchange-spring magnets and exchange-biased magnets will foster the realization of new materials that may be processed into the next generation of advanced permanent magnets.

Luminescence-tunable multicolored LaF

Luminescence-tunable multicolored LaF3:xCe3+,xGd3+,yEu3+ (x = 5; y = 1, 5, 10, and 15 mol%) nanoparticles have been synthesized via a low cost polyol method. Powder X-ray diffraction and high-resolution transmission electron microscopy studies confirm the hexagonal phase of the LaF3:xCe3+,xGd3+,yEu3+ nanophosphors with average sizes (oval shape) ranging from 5 to 7 nm. Energy-dispersive X-ray spectroscopy analyses show the uniform distribution of Ce3+, Gd3+, and Eu3+ dopants in the LaF3 host matrix. The photoluminescence spectra and electron paramagnetic resonance measurements guarantee the presence of Eu2+, corroborated through DC susceptibility measurements of the samples displaying paramagnetic behavior at 300 K, whereas weak ferromagnetic ordering is shown at 2 K. The non-radiative energy transfer processes from the 4f(2F5/2) → 5d state (Ce3+) to the intraconfigurational 4f excited levels of rare earth ions and simultaneous emissions in the visible region from the 4f65d1 (Eu2+) and 5D0 (Eu3+) emitting levels, leading to overlapped broad and narrow emission bands, have been proclaimed. The energy transfer mechanism proposes involvement of the Gd3+ ion sub-lattice as the bridge and finally trapping by Eu2+/3+, upon excitation of the Ce3+ ion. The calculation of experimental intensity parameters (Ω2,4) has been discussed and the highest emission quantum efficiency (η = 85%) of the Eu3+ ion for the y = 10 mol% sample is reported. The advantageous existence of the Eu2+/Eu3+ ratio along with variously doped nanomaterials described in this work, results in tunable emission color in the blue-white-red regions, highlighting the potential application of the samples in solid-state lighting devices, scintillation devices, and multiplex detection.

Multifunctional magnetic nanostructures have been appealing in nanoscience owing to their manifold importance in the superfluity of electronic devices and biomedical applications. The integration of multiple discrete functionalities of two or more nanoparticles in a single hybrid system with different types of structures leads to diverse execution capabilities in, for example, catalysis, magnetic sensors, magnetic read heads, and storage devices. These hybrid systems require a theoretical approach to realize their various unknown characteristics. This chapter presents a brief introduction to multifunctional complex magnetic nanostructures, their synthesis and characterization techniques, along with important applications in the magnetic sector. The major focus is on core-shell and dumbbell nanoparticles. Progress in theoretical models to explain complex magnetic phenomena is also discussed.

Microwave assisted solvothermal method has been employed to synthesize multifunctional upconverting β-NaGdF4:Ln3+ and magnetic-upconverting Fe3O4/γ-Fe2O3at NaGdF4:Ln3+ (Ln = Yb and Er) nanoparticles. The powder x-ray diffraction data confirms the hexagonal structure of NaGdF4:Ln3+ and high resolution transmission electron microscopy shows the formation of rod shaped NaGdF4:Ln3+ (∼ 20 nm) and ovoid shaped Fe3O4/γ-Fe2O3NaGdF4:Ln3+ (∼ 15 nm) nanoparticles. The magnetic hysteresis at 300 K for β-NaGdF4:Ln3+ demonstrates paramagnetic features, whereas iron-oxideβ-NaGdF4:Ln3+ exhibits superparamagnetic behavior along with a linear component at large applied field due to paramagnetic NaGdF4 matrix. Both nanoparticle samples provide an excellent green emitting [(2H11/2, 4S3/2)→4I15/2 (∼ 540 nm)] upconversion luminescence emission under excitation at 980 nm. The energy migration between Yb and Er in NaGdF4 matrix has been explored from 300-800 nm. Intensity variation of blue, green and red lines and the observed luminescence quenching due to the presence of Fe3O4/γ-Fe2O3 in the composite has been proposed. These kinds of materials contain magnetic and luminescence characteristics into single nanoparticle open new possibility for bioimaging applications. Fil: Shrivastava, Navadeep. Universidade Federal Do Maranhao.; Brasil Fil: Rocha, Uéslen. Universidade Federal de Alagoas; Brasil Fil: Muraca, Diego. Universidade Estadual de Campinas; Brasil Fil: Jacinto, Carlos. Universidade Federal de Alagoas; Brasil Fil: Moreno, Mario Sergio Jesus. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Vargas, Jose Marcelo. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina Fil: Sharma, S.K.. Universidade Federal Do Maranhao.; Brasil