Green synthesis of silver indium telluride nanocrystals: characterization and photothermal analyses.

Here, we report the preparation and characterization of stable AgIn5Te8 (AITe) nanocrystals (NCs) and their respective AITe-ZnS and AITe-ZnSe alloys. A green route of synthesis is described by using an aqueous electrochemical method in a cavity cell. The elemental ratio modulation of the NCs was investigated to determine the ideal improvement of the structural and electronic properties. The AITe NCs presented an emission band at 889 nm and hypsochromic shifts when coated with ZnS and ZnSe seeds. Photothermal analyses point to theranostic applications.

Dual-functional supramolecular nanohybrids of quantum dot/biopolymer/chemotherapeutic drug for bioimaging and killing brain cancer cells in vitro.

Glioblastoma (GBM) is the utmost aggressive and lethal primary brain cancer, which has a poor prognosis and remains virtually incurable. Nanomedicine with emerging disruptive nanotechnology alternatives, including designed supramolecular nanohybrids has excellent potential as multimodal tools against cancer by combining nanomaterials, biomacromolecules, and drugs. Thus, we developed and constructed for the first time quantum dot-biopolymer-drug nanohybrids based on host-guest chemistry for simultaneous bioimaging, targeting, and anti-cancer drug delivery against GBM cells in vitro. ZnS fluorescent quantum dots (ZnS-QDs) were produced using chemically modified polysaccharide, carboxymethylcellulose (CMC), as water-soluble capping ligand and biofunctional layer via a facile one-step eco-friendly aqueous colloidal process at room temperature and physiological pH. These hybrid inorganic-organic nanocolloids (ZnS@CMC) were electrostatically conjugated with doxorubicin (DOX) anti-cancer drug forming innovative supramolecular complexes (ZnS@CMC-DOX) for amalgamating bioimaging and killing cancer cells. These nanoconjugates were characterized regarding their optical and physicochemical properties combined with morphological and structural features. The cytocompatibility was evaluated by MTT assay using healthy and GBM cells. The results showed that ultra-small ZnS-QDs were expertly produced uniform nanocolloids (average size = 3.6 nm). They demonstrated photoluminescence emission within the visible range of spectra. The cell viability results in vitro showed no cytotoxicity of ZnS@CMC nanohybrids towards both cell types. In summary, the novelty of this research relies on using a nanotheranostic strategy for developing ZnS@CMC-DOX nanohybrids with supramolecular vesicle-like structures. They behaved simultaneously as active fluorescent nanoprobes and nanocarriers with modulated drug release for bioimaging and killing malignant glioma cells proving the high potential for applications in cancer nanomedicine.

The use of gold nanorods as a new vaccine platform against schistosomiasis.

Schistosomiasis is an important parasitic disease affecting >207 million people in 76 countries around the world and causing approximately 250,000 deaths per year. At present, the main strategy adopted for the control of schistosomiasis is the use of safe chemotherapy, such as praziquantel. However, the high rates of reinfection after treatment restrict the use of this treatment approach and assume the need for other forms of control such as vaccination. Sm29 is a protein that is localized in the Schistosoma mansoni tegument of adult worms and schistosomula and is considered a powerful vaccine candidate. Because of the chemical, physical and immunological characteristics of nanoparticles, nanocarriers have received increasing attention. In the field of nanotechnology, gold nanorods are considered potential vaccine carriers. In this study, we bound S. mansoni rSm29 protein to gold nanorods either directly or by cysteamine functionalization. When the worm burden was evaluated, the AuNRs-NH2-rSm29 group of immunized mice showed the best protection level (34%). Following AuNRs-NH2-rSm29 immunization, we observed a Th1 immunological response in mice with higher production of IFN-γ, mainly by CD4+ and CD8+ T cells. Furthermore, AuNRs-NH2-rSm29 could activate dendritic cells in vitro, enhancing MHCII and MHCI expression and the production of IL-1ß in a NLRP3-, ASC- and Caspase-1-dependent manner. In summary, our findings support the use of nanorods as an immunization strategy in vaccine development against infectious diseases.

One-Pot Aqueous Synthesis of Fluorescent Ag-In-Zn-S Quantum Dot/Polymer Bioconjugates for Multiplex Optical Bioimaging of Glioblastoma Cells.

Cancer research has experienced astonishing advances recently, but cancer remains a major threat because it is one of the leading causes of death worldwide. Glioblastoma (GBM) is the most malignant brain tumor, where the early diagnosis is vital for longer survival. Thus, this study reports the synthesis of novel water-dispersible ternary AgInS2 (AIS) and quaternary AgInS2-ZnS (ZAIS) fluorescent quantum dots using carboxymethylcellulose (CMC) as ligand for multiplexed bioimaging of malignant glioma cells (U-87 MG). Firstly, AgInS2 core was prepared using a one-pot aqueous synthesis stabilized by CMC at room temperature and physiological pH. Then, an outer layer of ZnS was grown and thermally annealed to improve their optical properties and split the emission range, leading to core-shell alloyed nanostructures. Their physicochemical and optical properties were characterized, demonstrating that luminescent monodispersed AIS and ZAIS QDs were produced with average sizes of 2.2 nm and 4.3 nm, respectively. Moreover, the results evidenced that they were cytocompatible using in vitro cell viability assays towards human embryonic kidney cell line (HEK 293T) and U-87 MG cells. These AIS and ZAIS successfully behaved as fluorescent nanoprobes (red and green, resp.) allowing multiplexed bioimaging and biolabeling of costained glioma cells using confocal microscopy.

Composition-Tunable Optical Properties of Zn x Cd(1 - x)S Quantum Dot-Carboxymethylcellulose Conjugates: Towards One-Pot Green Synthesis of Multifunctional Nanoplatforms for Biomedical and Environmental Applications.

Quantum dots (QDs) are colloidal semiconductor nanocrystals with unique properties that can be engineered by controlling the nanoparticle size and chemical composition by doping and alloying strategies. However, due to their potential toxicity, augmenting their biocompatibility is yet a challenge for expanding to several biomedical and environmentally friendly applications. Thus, the main goal of this study was to develop composition-tunable and biocompatible Zn x Cd1 - x S QDs using carboxymethylcellulose polysaccharide as direct capping ligand via green colloidal aqueous route at neutral pH and at room temperature for potential biomedical and environmental applications. The ternary alloyed QDs were extensively characterized using UV-vis spectroscopy, photoluminescence spectroscopy (PL), transmission electron microscopy (TEM), X-ray diffraction (XRD), electron energy loss spectroscopy (EELS), and X-ray photoelectrons spectroscopy (XPS). The results indicated that Zn x Cd(1 - x)S QDs were surface stabilized by carboxymethylcellulose biopolymer with spherical morphology for all composition of alloys and narrow sizes distributions ranging from 4 to 5 nm. The XRD results indicated that monophasic ternary alloyed Zn x Cd1 - x S nanocrystals were produced with homogenous composition of the core as evidenced by EELS and XPS analyses. In addition, the absorption and emission optical properties of Zn x Cd1 - x S QDs were red shifted with increasing the amount of Cd2+ in the alloyed nanocrystals, which have also increased the quantum yield compared to pure CdS and ZnS nanoparticles. These properties of alloyed nanomaterials were interpreted based on empirical model of Vegard's law and chemical bond model (CBM). As a proof of concept, these alloyed-QD conjugates were tested for biomedical and environmental applications. The results demonstrated that they were non-toxic and effective fluorophores for bioimaging live HEK293T cells (human embryonic kidney cells) using confocal laser scanning fluorescence microscopy. Moreover, these conjugates presented photocatalytic activity for photodegradation of methylene blue used as model organic industrial pollutant in water. Hence, composition-tunable optical properties of ternary Zn x Cd1 - x S (x = 0-1) fluorescent alloyed QDs was achieved using a facile eco-friendly aqueous processing route, which can offer promising alternatives for developing innovative nanomaterials for applications in nanomedicine and environmental science and technology.