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Smart theranostic nanoprobes with the integration of multiple therapeutic modalities are preferred for precise diagnosis and efficient therapy of tumors. However, it remains a big challenge to arrange the imaging and two or more kinds of therapeutic agents without weakening the intended performances. In addition, most existing fluorescence (FL) imaging agents suffer from low spatiotemporal resolution due to the short emission wavelength (<900 nm). Here, novel three-in-one Ag2S quantum dot (QD)-based smart theranostic nanoprobes were proposed for in situratiometric NIR-II FL imaging-guided ion/gas combination therapy of tumors. Under the acidic tumor microenvironment, three-in-one Ag2S QDs underwent destructive degradation, generating toxic Ag+and H2S. Meanwhile, their FL emission at 1270 nm was weakened. Upon introduction of a downconversion nanoparticle (DCNP) as the delivery carrier and NIR-II FL reference signal unit, the formed Ag2S QD-based theranostic nanoprobes could achieve precise diagnosis of tumors through ratiometric NIR-II FL signals. Also, the generated Ag+and H2S enabled specific ion/gas combination therapy toward tumors. By combining the imaging and therapeutic functions, three-in-one Ag2S QDs may open a simple yet reliable avenue to design theranostic nanoprobes.

By integrating near-infrared (NIR) light-dependent optical control and DNA walkers-based signal amplification, upconversion luminescence-activated DNA nanomachines hold great potential in conducting an in vivoanalysis. For the typical DNA nanomachines, the immobile multivalent recognition interface greatly compromised the reaction kinetics and amplification efficiency due to the cleavage-dependent response mode. In this work, novel upconversion luminescence-activated DNA nanomachines with a fluid multivalent recognition interface were reported for rapid and sensitive in vivoimaging. As a proof-of-concept study, the photolocked DNAzyme-based walker system was anchored on the surface of phospholipid membrane-coated upconversion nanoparticles through the cholesterol–phospholipid interaction to acquire a fluid multivalent recognition interface. Upon sequential inputs of NIR light and metal ions, the formed DNA nanomachines were autonomously initiated and generated a cascade of amplified signal. Relative to the typical DNA nanomachines, the proposed ones possess an accelerated reaction rate and an improved amplification capability owing to a higher local concentration by the lateral mobility. The present work provides a versatile alternative for performing precise and highly efficient in vivoanalysis.

Slow intermolecular collisions and “always active” responses compromise the amplification efficiency and response accuracy of nonenzymatic hybridization chain reaction (HCR). In this study, a photoactivatable membrane-oriented HCR (MOHCR) system was rationally designed by binding a photocleavable initiator probe onto a target protein and then anchoring cholesterol-modified hairpin-structure fuel probes. When irradiated, the bound initiator probe was photoactivated and initiated self-assembly to generate activatable and amplified imaging. In a proof-of-concept assay, breast-cancer-derived exosomes were imaged based on the surface protein epithelial cell adhesion molecule (EpCAM). Photoactivatable responses provided precise spatiotemporal control of the MOHCR, and fluidic membranes enabled accelerated reaction kinetics. Our MOHCR system demonstrated high efficiency and accuracy in differentiating between plasma samples from breast cancer patients and healthy donors.

Down/upconversion Ca14Al10Zn6O35inorganic phosphors codoped with Ti4+/Eu3+or Yb3+/Er3+were prepared. The crystal structure and downconversion luminescence properties of Ca14Al10Zn6O35:Ti4+, Eu3+phosphors were studied in detail. Ti4+and Eu3+occupied Al3+and Ca2+sites in the host lattice, respectively. Under the excitation of 273 nm, the emission peak in the 300–570 nm band originated from the 2T2→ O2–transition of Ti4+. The f–f transition of Eu3+ions generated multiple peaks in the 570–800 nm range. The emission intensity of Ti4+and Eu3+ions can be used as a fluorescence intensity ratio (FIR) signal. Based on the FIR technology, the maximum relative sensitivity (Sr) and the minimum temperature uncertainty (δT) reached 1.41% K–1and 0.07 K, respectively. Meanwhile, the temperature-sensing behaviors were explored by the temperature-dependent upconversion spectra of Er3+- and Yb3+-codoped Ca14Al10Zn6O35phosphors. Based on the fluorescence intensity ratio of thermal coupling levels (Er3+:2H11/2/4S3/2), the maximum Srand minimum δTof upconversion phosphors reached 1.28% K–1and 0.08 K in the temperature range of 293–473 K, respectively. Ca14Al10Zn6O35:Ti4+/Eu3+(Yb3+/Er3+) phosphors realize temperature sensors with higher relative sensitivity, and it is a good candidate material for optical temperature measurement.

A novel non-contact optical thermometer, qualified with high sensitivity and temperature resolution, is urgently needed for temperature measuring of micro devices, moving objects and specific severe environments. Hence, a series of dual-emitting La5Si2BO13:Ce3+,Eu2+phosphors were synthesized. The two ions show diverse responses with the changing in temperature. The variational emissions of Ce3+and Eu2+can be converted to FIR (fluorescence intensity ratio) signals. The maximal absolute sensitivity Saand relative sensitivity Srreach up to 0.07526%/K and 3.2241%/K, respectively. It is worthy noting that the Saand Srpossess the same variation tendency and both have high values in the low temperature region (293–373 K), showing the great temperature measuring property especially in low temperature region. The temperature sensing characteristics are superior to the results of most previous reports. The energy transfer (ET) process is certified to occur from Ce3+to Eu2+ions. These studies indicate that La5Si2BO13: Ce3+,Eu2+phosphor could have a good prospect for optical thermometry.

Eu2+/Sm3+co-doped dual-emitting Sr4La(PO4)3O phosphors were synthesized through a convenient high temperature solid state reaction in reductive atmosphere. The structure, luminescence, energy transfer and temperature-dependent luminescence properties of Eu2+/Sm3+co-doped Sr4La(PO4)3O phosphors were researched and analyzed in detail. The blue emission of Eu2+and the red emission of Sm3+can work together as FIR signals. Based on the different response characteristics of these two ion emissions to temperature, Sr4La(PO4)3O:Eu2+/Sm3+phosphor achieves the relative sensitivity of 0.48384%/K and a wide range of temperature measurements from room temperature to 573 K. The results reveal that the Sr4La(PO4)3O:Eu2+/Sm3+phosphor has application prospect in the field of high temperature optical thermometry. The energy transfer mechanism is proved to be the dipole-dipole interaction between Eu2+and Sm3+ions.

ABSTRACTThe control of Ostrinia furnacalis, a major pest of maize in Xinjiang, is challenging owing to the occurrence of resistant individuals. Entomopathogenic fungi (EPF) are natural insect regulators used as substitutes for synthetic chemical insecticides. The fungus Aspergillus nomiusis highly pathogenic to O. furnacalis; however, its virulence characteristics have not been identified. This study aimed to analyse the lethal efficacy, mode of infection on the cuticle, and extracellular enzyme activity of A. nomiusagainst O. furnacalis. We found that the mortality and mycosis of O. furnacaliswere dose-dependent when exposed to A. nomiusand varied at different life stages. The egg-hatching and adult emergence rates decreased with an increase in conidial suspension. The highest mortality (83.33%, 7 d post-infection [DPI]) and mycosis (74.33%, 7 DPI) and the lowest mortality response (8.52 × 103conidia mL−1) and median lethal time (4.91 d) occurred in the 3rdinstar larvae of O. furnacalis. Scanning electron microscopy indicated that numerous conidia germination and infection structure formation may have contributed to the high pathogenicity of A. nomiusagainst O. furnacalis. There were significant correlations between O. furnacalismortality and the activities of extracellular protease, lipase, and chitinase of A. nomius. This study revealed the infection process of the highly pathogenic A. nomiusagainst O. furnacalis, providing a theoretical basis and reference for strain improvement and field application of EPF.

Tumor microenvironment-mediated ratiometric second near-infrared (NIR-II) fluorescence imaging and photodynamic therapy contribute to accurate diagnosis and highly efficient therapy of deep tumors. However, it is challenging to integrate these functions into one nanodrug due to the difficulty in preparing triple-emission nanoprobes. In this work, single-excitation triple-emission (wavelength at 660, 1060, and 1550 nm) down-/up-conversion nanoassemblies were prepared by conjugating dual-ligands-stabilized gold nanoclusters (cgAuNCs) into down-/up-conversion nanoparticles (D/UCNPs), which simultaneously realized ratiometric NIR-II fluorescence imaging and chemo-/photodynamic combination therapy toward tumors upon exposure to an 808 nm laser. The presence of dual ligands endowed cgAuNCs with an enhanced NIR-II fluorescence response to endogenous glutathione, allowing in situ ratiometric NIR-II fluorescence imaging of tumors using the prepared nanoassemblies. Additionally, the stabilizing ligand cyclodextrin of cgAuNCs facilitated the loading of the antitumor drug doxorubicin, and D/UCNPs could be modified with the photosensitizer methylene blue. Such a spatially separated functionalization method enabled chemo-/photodynamic combination therapy. This study provides new insights into the design of multifunctional nanoplatforms for tumor diagnosis and treatment.