AgInS 2 −ZnS (AIZS) nanocrystals (NCs) were synthesized using a simple one-step approach by heating a Ag/ In/Zn/S solution to 210 °C providing highly tunable photoluminescence (PL). The incorporation of Zn even at low temperatures (∼150 °C) and the increased cation exchange of silver by zinc at higher temperatures strongly influence the optical properties of the resulting NCs. The correlation between synthesis parameters and resulting optical properties provided insights on the growth and stability of ternary and quaternary semiconductors. Systematic investigation with time-resolved spectroscopy showed distinguishable PL behaviors between developing and fully grown AIZS NCs. Attempts to coat as-prepared AgInS 2 NCs resulted in the same PL behavior as the one-step reaction product indicating that Zn readily exchanges with Ag ions even when not directly incorporated in the initial reaction mixture. Even with a low amount of zinc, the fully grown AIZS NCs showed improved PL QYs and single exponential decay behavior with long PL lifetimes. Control of the optical properties of these NCs makes them potentially useful for applications in photovoltaics and bioimaging particularly in light of their nontoxicity.

Highly fluorescent Ag nanoclusters were prepared in aqueous solution via a rapid microwave-assisted green approach and used as a novel fluorescence probe for the determination of Cr(3+) ions with high sensitivity and excellent selectivity.

The catalytic activity of nanocrystal catalysts depends strongly on their structures. Herein, we report three distinct structures of Fe(3)O(4) nanocrystals, cluster spheres, octahedra, and triangular plates, prepared by a similar hydrothermal procedure. Additionally, the three Fe(3)O(4) nanostructures were used as peroxidase nanomimetics and the correlation between the catalytic activities and the structures was first explored by using 3,3',5,5'-tetramethylbenzidine and H(2)O(2) as peroxidase substrates. The results showed that the peroxidase-like activities of the Fe(3)O(4) nanocrystals were structure dependent and followed the order cluster spheres>triangular plates>octahedra; this order was closely related to their preferential exposure of catalytically active iron atoms or crystal planes. Such investigation is of great significance for peroxidase nanomimetics with enhanced activity and utilization.

Our exploiting versatile multimodal theranostic agent aims to integrate the complementary superiorities of photoacoustic imaging (PAI), second near-infrared (NIR-II, 1000-1700) fluorescence and T 1 -weighted magnetic resonance imaging (MRI) with an ultimate objective of perfecting cancer diagnosis, thus improving cancer therapy efficacy. Herein, we engineered and prepared a water-soluble gadolinium-chelated conjugated polymer-based theranostic nanomedicine (PFTQ-PEG-Gd NPs) for in vivo tri-mode PA/MR/NIR-II imaging-guided tumor photothermal therapy (PTT). Methods : We firstly constructed a semiconducting polymer composed of low-bandgap donor-acceptor (D-A) which afforded the strong NIR absorption for PAI/PTT and long fluorescence emission to NIR-II region for in vivo imaging. Then, the remaining carboxyl groups of the polymeric NPs could effectively chelate with Gd 3+ ions for MRI. The in vitro characteristics of the PFTQ-PEG-Gd NPs were studied and the in vivo multimode imaging as well as anti-tumor efficacy of the NPs was evaluated using 4T1 tumor-bearing mice. Results : The obtained theranostic agent showed excellent chemical and optical stability as well as low biotoxicity. After 24 h of systemic administration using PQTF-PEG-Gd NPs, the tumor sites of living mice exhibited obvious enhancement in PA, NIR-II fluorescence and positive MR signal intensities. Better still, a conspicuous tumor growth restraint was detected under NIR light irradiation after administration of PQTF-PEG-Gd NPs, indicating the efficient photothermal potency of the nano-agent. Conclusion : we triumphantly designed and synthesized a novel and omnipotent semiconducting polymer nanoparticles-based theranostic platform for PAI, NIR-II fluorescence imaging as well as positive MRI-guided tumor PTT in living mice. We expect that such a novel organic nano-platform manifests a great promise for high spatial resolution and deep penetration cancer theranostics.

Photodynamic therapy (PDT) is a noninvasive and site‐specific therapeutic technique for the clinical treatment of various of superficial diseases. In order to tuning the operation wavelength and improve the tissue penetration of PDT, rare‐earth doped upconversion nanoparticles (UCNPs) with strong anti‐stokes emission are introduced in PDT recently. However, the conventional Yb3+‐sensitized UCNPs are excited at 980 nm which is overlapped with the absorption of water, thus resulting in strong overheating effect. Herein, a convenient but effective design to obtain highly emissive 795 nm excited Nd3+‐sensitized UCNPs (NaYF4:Yb,Er@NaYF4:Yb0.1Nd0.4@NaYF4) is reported, which provides about six times enhanced upconversion luminescence, comparing with traditional UCNPs (NaYF4:Yb,Er@NaYF4). A colloidal stable and non‐leaking PDT nanoplatform is fabricated later through a highly PEGylated mesoporous silica layer with covalently linked photosensitizer (Rose Bengal derivative). With as‐prepared Nd3+‐sensitized UCNPs, the nanoplatform can produce singlet oxygen more effective than traditional UCNPs. Significant higher penetration depth and lower overheating are demonstrated as well. All these features make as‐prepared nanocomposites excellent platform for PDT treatment. In addition, the nanoplatform with uniform size, high surface area, and excellent colloidal stability can be extended for other biomedical applications, such as imaging probes, biosensors, and drug delivery vehicles.

Monodispersed Fe3O4 nanospheres with hollow interior structures exhibiting high saturation magnetization of 83.0 emu g−1 were fabricated by a facile one-pot route. The fabrication process is very simple with only FeCl3·6H2O and anhydrous NaAc as the reactants in an ethylene glycol solution with no templates or surfactants involved. Field-emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and a superconducting quantum interference device magnetometer were used to characterize the morphologies, structures, and properties of the hollow magnetic nanospheres. A plausible mechanism based on oriented attachment and subsequent local Ostwald ripening is proposed. In addition, the experiments of the hollow nanospheres decorated with polyacrylic acids as drug carriers and Rhodamine 6G as a model drug, revealed pH- or salt-responsive release profiles, thus demonstrating the potential of these nanostructures in biomedical applications.

Magnetic field-responsive iron oxide-loaded hollow mesoporous silica nanocapsules that exhibit high drug loading capacity were synthesized using polymer nanospheres as sacrificial templates. Due to their magnetic field induced heating and remotely triggered drug release capabilities, these hybrid nanomaterials provide an excellent platform for the combination of hyperthermia and chemotherapy.

Activatable second near‐infrared window (NIR‐II; 1.0–1.7 µm) fluorescence probes that uncage deep‐tissue penetrating fluorescence by disease‐related biomarker stimuli hold great promise for detecting diseases with a poor understanding of the pathology at the molecular level with unprecedented resolution. However, currently, very few activatable NIR‐II fluorescence probes are reported mainly due to the lack of a simple yet general design strategy. Herein, a new and fairly generic design strategy using a bio‐erasable intermolecular donor–acceptor interaction to construct activatable NIR‐II fluorescence probes is reported. An organic semiconducting nanoprobe (SPNP) is constructed through blending a biomarker‐sensitive organic semiconducting non‐fullerene acceptor (3,9‐bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)‐cyclopentane‐1,3‐dione‐[c]thiophen))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d:2',3'‐d']‐s‐indaceno[1,2‐b:5,6‐b'] dithiophene) (ITTC) (one of electric acceptors in organic solar cells) with a biomarker‐inert semiconducting polymer donor 5‐(4,8‐bis((2‐ethylhexyl)oxy)‐6‐methylbenzo[1,2‐b:4,5‐b']difuran‐2‐yl)‐10‐methylnaphtho[1,2‐c:5,6‐c']bis([1,2,5]thiadiazole) (PDF) in an amphiphilic‐polymer‐coated single nanoparticle to suppress NIR‐II fluorescence of the donor via a intermolecular donor–acceptor interaction. The acceptor ITTC is found to be specifically degraded by hypochlorite (an important biomarker) to erase its acceptor property, thus erasing the intermolecular donor–acceptor interaction and uncaging NIR‐II fluorescence. Consequently, SPNP exhibits a 17.5‐fold higher fluorescence brightness in the hypochlorite‐abnormal inflammation in vivo than in normal tissues. Our bio‐erasable intermolecular donor–acceptor interaction strategy provides simple yet general guidelines to design various biomarker‐activatable NIR‐II fluorescence probes.