Enhancing NIR-II Upconversion Monochromatic Emission for Temperature Sensing.

The upconversion luminescence (UCL) in the second near-infrared window (NIR-II) is highly attractive due to its excellent performance in high-resolution bioimaging, anticounterfeiting, and temperature sensing. However, upconvertion nanoparticles (UCNPs) are normally emitted in visible light, potentially impacting the imaging quality. Here, a monochromatic Er-rich (NaErF:x%Yb@NaYF) nanoparticles with excitation at 1532 nm and emission at 978 nm is proposed, both situated in the NIR-II region.

Cross Relaxation Channel Tailored Temperature Response in Er -rich Upconversion Nanophosphor.

Recently high doping of lanthanide ions (till 100 %) is realized unprecedentedly in nanostructured upconversion (UC) phosphors. However, oddly enough, this significant breakthrough did not result in a corresponding UC enhancement at ambient temperature, which hinders the otherwise very interesting applications of these materials in various fields. In this work, taking the Er -rich UC nanosystem as an example, we confirm unambiguously that the phonon-assisted cross relaxation (CR) is the culprit.

Significant Enhancement of the Upconversion Emission in Highly Er -Doped Nanoparticles at Cryogenic Temperatures.

Relatively low efficiency is the bottleneck for the application of lanthanide-doped upconversion nanoparticles (UCNPs). The high-level doping strategy realized in recent years has not improved the efficiency as much as expected. It is argued that cross relaxation (CR) is not detrimental to upconversion.

Manipulating the Injected Energy Flux via Host-Sensitized Nanostructure for Improving Multiphoton Upconversion Luminescence of Tm.

Combating the concentration quenching effect by increasing the concentration of sensitized rare-earth ions in rational design upconversion nanostructure will make it easier to utilize injection energy flux and transfer it to emitters, resulting in improved upconversion luminescence (UCL). We proposed a host-sensitized nanostructure (active core@luminescent shell@inert shell) to improve multiphoton UCL of Tm based on the LiLnF host. Yb ions were isolated in the core as energy absorbents, and Tm was doped in the interior LiYbF host shell.

A scintillating nanoplatform with upconversion function for the synergy of radiation and photodynamic therapies for deep tumors.

Collaborative therapy is regarded as an effective approach in increasing the therapeutic efficacy of cancer. In this work, we have proposed and validated the concept of upconversion lumienscence image guided synergy of photodynamic therapy (PDT) and radiotherapy (RT) for deep cancer, a specially designed nanoplatform integrating near infrared (NIR) light activated luminescence upconversion and X-ray induced scintillation. Upon NIR light irradiation, the nanoplatform emits highly monochromatic red light solely for imaging the targeted cancer cells without triggering therapy; however, when the irradiation turns to a low dose of X-rays, scintillation will occur which induces effectively the PDT destroying the cancer cells together with X-ray induced RT.

Hybrid Nanoplatform: Enabling a Precise Antitumor Strategy via Dual-Modal Imaging-Guided Photodynamic/Chemo-/Immunosynergistic Therapy.

Photodynamic therapy (PDT) has been widely used in tumor therapy due to its high spatial-temporal control and noninvasiveness. However, its clinical application is limited by weak efficacy, shallow tissue penetration, and phototoxicity. Herein, a facile theranostic nanoplatform based on photoswitchable lanthanide-doped nanoparticles was designed.

Internal OH induced cascade quenching of upconversion luminescence in NaYF:Yb/Er nanocrystals.

Internal hydroxyl impurity is known as one of the main detrimental factors affecting the upconversion (UC) efficiency of upconversion luminescence (UCL) nanomaterials. Different from surface/ligand-related emission quenching which can be effectively diminished by, e.g.

Ultrastrong Absorption Meets Ultraweak Absorption: Unraveling the Energy-Dissipative Routes for Dye-Sensitized Upconversion Luminescence.

Dye sensitization is becoming a new dimension to highly improve the upconversion luminescence (UCL) of lanthanide-doped upconversion nanoparticles (UCNPs). However, there is still a lack of general understanding of the dye-UCNPs interactions, especially the confused large mismatch between the inputs and outputs. By taking dye-sensitized NaYF:Yb/Er@NaYF:Nd UCNPs as a model system, we not only revealed the in-depth energy-dissipative process for dye-sensitized UCL but also confirmed the first ever experimental observation of the energy back transfer (EBT) in the dye-sensitized UCL.

An 800 nm driven NaErF@NaLuF upconversion platform for multimodality imaging and photodynamic therapy.

Multimodality imaging-guided therapy based on lanthanide-doped upconversion nanoparticles (UCNPs) has become a trend in cancer theranostics. However, the overheating effect of 980 nm excitation in photodynamic therapy (PDT) and the difficulties in optimizing multimodality imaging integration within a single particle are still challenges. Herein, 800 nm driven NaErF4@NaLuF4 UCNPs have been explored for optimized multimodality imaging and near-infrared (NIR) triggered PDT.

Near Infrared Light Sensitive Ultraviolet-Blue Nanophotoswitch for Imaging-Guided "Off-On" Therapy.

Photoswitchable materials are important in broad applications. Recently appeared inorganic photoswitchable upconversion nanoparticles (PUCNPs) become a competitive candidate to surmount the widespread issue of the organic counterparts -photobleaching. However, current PUCNPs follow solely Yb/Nd cosensitizing mode, which results in complex multilayer doping patterns and imperfectness of switching in UV-blue region.

Precisely Tailoring Upconversion Dynamics via Energy Migration in Core-Shell Nanostructures.

Upconversion emission dynamics have long been believed to be determined by the activator and its interaction with neighboring sensitizers. Herein this assumption is, however, shown to be invalid for nanostructures. We demonstrate that excitation energy migration greatly affects upconversion emission dynamics.

Bcl-2 inhibitor uploaded upconversion nanophotosensitizers to overcome the photodynamic therapy resistance of cancer through adjuvant intervention strategy.

Similar to many other anticancer therapies, photodynamic therapy (PDT) also suffers from the intrinsic cancer resistance mediated by cell survival pathways. These survival pathways are regulated by various proteins, among which anti-apoptotic protein Bcl-2 plays an important role in regulation of programmed cell death and has been proved to involve in protecting against oxidative stimuli. Confronted by this challenge, we propose and validate here a novel upconversion photosensitizing nanoplatform which enables significant reduction of cancer resistance and improve PDT efficacy.

Employing shells to eliminate concentration quenching in photonic upconversion nanostructure.

It is generally accepted that a lanthanide ions based upconversion material follows an activator low doping strategy (normally <3 mol%), because of the restriction of the harmful concentration quenching effect. Here, we demonstrate that this limitation can be broken in nanostructures. Simply by using an inert shell coating strategy, the concentration quenching effect for the activator (Er) could be eliminated and highly efficient upconversion luminescence realized in the activator fully doped nanostructure, e.

Precise Photodynamic Therapy of Cancer via Subcellular Dynamic Tracing of Dual-loaded Upconversion Nanophotosensitizers.

Recent advances in upconversion nanophotosensitizers (UCNPs-PS) excited by near-infrared (NIR) light have led to substantial progress in improving photodynamic therapy (PDT) of cancer. For a successful PDT, subcellular organelles are promising therapeutic targets for reaching a satisfactory efficacy. It is of vital importance for these nanophotosensitizers to reach specifically the organelles and to perform PDT with precise time control.

Accurate Quantitative Sensing of Intracellular pH based on Self-ratiometric Upconversion Luminescent Nanoprobe.

Accurate quantitation of intracellular pH (pH) is of great importance in revealing the cellular activities and early warning of diseases. A series of fluorescence-based nano-bioprobes composed of different nanoparticles or/and dye pairs have already been developed for pH sensing. Till now, biological auto-fluorescence background upon UV-Vis excitation and severe photo-bleaching of dyes are the two main factors impeding the accurate quantitative detection of pH.

One-step in situ solid-substrate-based whole blood immunoassay based on FRET between upconversion and gold nanoparticles.

Despite their general clinical applications, current fluorescence-based immunoassays are confronted with serious challenges, e.g. the advance serum/ plasma separation and the tedious washing process in current heterogeneous approaches, and aggregation of particles, low sensitivity and the narrow linear range in homogeneous approaches.

A SERS nano-tag-based fiber-optic strategy for in situ immunoassay in unprocessed whole blood.

Assay technologies capable of detecting biomarker concentrations in unprocessed whole blood samples are fundamental for applications in medical diagnostics. SERS nano-tags integrated fiber-optic biosensor (FOB) was realized for the first time for in situ immunoassay in whole blood. The reliability and sensitivity of this method rely, in a large extent, on the quality and properties of the SERS nano-tags.

Correction: In vivo 808 nm image-guided photodynamic therapy based on an upconversion theranostic nanoplatform.

Correction for 'In vivo 808 nm image-guided photodynamic therapy based on an upconversion theranostic nanoplatform' by Xiaomin Liu, et al., Nanoscale, 2015, 7, 14914-14923.

A highly effective in vivo photothermal nanoplatform with dual imaging-guided therapy of cancer based on the charge reversal complex of dye and iron oxide.

To enhance the treatment efficiency of photothermal therapy (PTT) with very little light-associated side effect, we have constructed a highly effective PTT nanoplatform for fluorescence and MRI dual imaging-guided PTT of cancer, based on IR806 dye and iron oxide complex functionalized with mPEG-PCL-G2.0PAMAM-Cit, which can be for charge-conversion for targeted accumulation in tumor. Combination of iron oxide nanoparticles and IR806 improve light to thermal conversion efficiency and lower light irradiation dose.

A facile and general route to synthesize silica-coated SERS tags with the enhanced signal intensity.

Silica-coated SERS tags have been attracting greater attention in recent years. However, the reported methods to synthesize these tags are tedious, and often subjected to the limited signal intensity. Here, we report a facile and general method to prepare the silica-coated Ag SERS tags with the enhanced signal intensity by no introducing the primers.

In vivo 808 nm image-guided photodynamic therapy based on an upconversion theranostic nanoplatform.

A new strategy for efficient in vivo image-guided photodynamic therapy (PDT) has been demonstrated utilizing a ligand-exchange constructed upconversion-C60 nanophotosensitizer. This theranostic platform is superior to the currently reported nanophotosensitizers in (i) directly bonding photosensitizer C60 to the surface of upconversion nanoparticles (UCNPs) by a smart ligand-exchange strategy, which greatly shortened the energy transfer distance and enhanced the (1)O2 production, resulting in the improvement of the therapeutic effect; (ii) realizing in vivo NIR 808 nm image-guided PDT with both excitation (980 nm) and emission (808 nm) light falling in the biological window of tissues, which minimized auto-fluorescence, reduced light scatting and improved the imaging contrast and depth, and thus guaranteed noninvasive diagnostic accuracy. In vivo and ex vivo tests demonstrated its favorable bio-distribution, tumor-selectivity and high therapeutic efficacy.

Near infrared light-driven water oxidation in a molecule-based artificial photosynthetic device using an upconversion nano-photosensitizer.

We provide the first demonstration of a near infrared light driven water oxidation reaction in a molecule-based artificial photosynthetic device using an upconversion nano-photosensitizer. One very attractive advantage of this system is that using NIR light irradiation does not cause significant photodamage, a serious problem in molecular based artificial photosynthesis under visible light irradiation.

Towards high quality triangular silver nanoprisms: improved synthesis, six-tip based hot spots and ultra-high local surface plasmon resonance sensitivity.

The great application potential of triangular silver nanoprisms (TSNPRs, also referred to as triangular silver nanoplates) is hampered by the lack of methods to produce well-defined tips with high monodispersity, with easily removable ligands. In this work, a simple one-step plasmon-mediated method was developed to prepare monodisperse high-quality TSNPRs. In this approach, the sole surface capping agent was the easily removable trisodium citrate.

Targeted labeling of an early-stage tumor spheroid in a chorioallantoic membrane model with upconversion nanoparticles.

In vivo detection of cancer at an early-stage, i.e. smaller than 2 mm, is a challenge in biomedicine.