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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, via 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. The novel theranostic nanoplatform is constructed in such a way that the interactions between the upconversion core and the outmost scintillating shell are blocked effectively by an inert layer between them. This structural design not only enables a nearly perfect excitation energy delivery (∼100% at a spectral overlapping wavelength of ∼540 nm) from the outermost scintellating layer to the surface-anchored photosensitizers and so a maximum yield of radical oxygen species, but also achieves a strong NIR induced upconversion luminescence for imaging. Since PDT and RT attack different parts of a cancer cell, this synergy is more effective in destroying cancer than a single therapy, resulting in the reduction of the X-ray irradiation dosage. As a proof of principle, the theranostic effect is validated by in vitro and in vivo experiments, exhibiting the great potential of this sort of nanoplatform in deep cancer treatment. [ABSTRACT FROM AUTHOR]

Color-modulated upconversion nanoparticles (UCNPs) have garnered widespread optical applications owing to their superior properties, including low auto-fluorescence background noise, large anti-Stokes shift, and distinguishable sharp emission bands. Recent success in multicolor alteration of UCNPs has mostly relied on the cross-relaxation between activators and other elements, which allows them to perform excellently in optical encoding and bioimaging. However, the color modulation is subject to the cross-relaxation strategy, which heavily weakens the original emission intensity of the activators. Herein, we report a dye-sensitization strategy of conjugating strong near-infrared absorptive dyes on the surface of UCNPs. It was proven that dye sensitization can manipulate the red to green (R/G) emission ratio of NaYF4:Yb/Er@NaYF4:Nd UCNPs and simultaneously enhance their luminescence intensity. The R/G emission ratio can be tuned to increase or decrease, benefiting from the dye sensitization strategy. Proof of concept was demonstrated for anti-counterfeiting application under orthogonal excitation of 808 nm and 980 nm. [ABSTRACT FROM AUTHOR]

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. In vitro and in vivo tests demonstrated that an effective dual imaging-guided PTT as low as 0.25 W cm−2 could be realized under a light irradiation of 808 nm. These efforts highlight the potential of this PTT nanoplatform in “precision medicine”. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Recent efforts and progress in unraveling the fundamental mechanism of excitation energy migration dynamics in upconversion nanomaterials are covered in this review, including short- and long-term interactions and other interactions in homogeneous and heterogeneous nanostructures. Comprehension of the role of spatial confinement in excitation energy migration processes is updated. Problems and challenges are also addressed. [ABSTRACT FROM AUTHOR]

Applying the Stöber method to directly coat noble metal nanoparticles (NPs) such as gold (Au) and silver (Ag) NPs with silica shells presents challenges, since the noble metal NPs are not stable in alcoholic solution and have low chemical affinity for silica. This paper describes a method which uses 11-mercaptoundecanoic acid (MUA) as a linker molecule between the silica shell and the noble metal NPs. MUA binds strongly to the surface of the NPs via a metal–S bond by replacing the standard capping agents on the surface of the NPs. Upon MUA stabilization, the NPs can be transferred into alcohol solution and show chemical affinity for silica. The MUA-modified NPs can be directly coated with thickness controlled, smooth and homogeneous silica shells via the standard Stöber method by varying the amount of tetraethoxysilane (TEOS). Compared with methods reported in the literature for the coating of such particles, this method can not only be used to successfully coat citrated-stabilized Au or Ag NPs, but can also be extended to encapsulate oleylamine (OA)-stabilized Au NPs and cetyltrimethylammonium bromide (CTAB)-stabilized Au nanorods (NRs) by using MUA to displace the original ligand on the surface of the NPs. Additionally, the obtained metal@SiO2 core–shell NPs have been successfully applied as plasmonic nanoantennas for fluorescence enhancement in metal@SiO2@fluorophore NPs. [ABSTRACT FROM AUTHOR]

To design more effective CIEEL (chemically initiated electron exchange luminescence) systems demands a complete picture of the dynamics of the chemiluminescence, which is often a challenge. In this work, photoluminescence of the methyl m-oxybenzoate anion – the authentic emitter of AMPPD (3-[2-spiroadamantane]-4-methoxy-4-[3-phosphoryloxy]-phenyl-1,2-dioxetane) in aqueous solvent has been studied. Combining the effect of solvent properties, e.g.pH value, and spectroscopic studies employing steady-state and ultrafast time-resolved emission and absorption and 1H NMR techniques, a novel mechanism is proposed. We conclude that the deviation of emission peaks between chemiluminescence and photoluminescence of the authentic emitter of AMPPD i.e.the methyl m-oxybenzoate anion, in alkaline aqueous solvents is due to its hydrolysis, rather than the hydrogen-bonding effect as has been assumed so far. Besides, the hydrogen-bonding is suggested to play a key role in significantly decreasing the chemiluminescence yield of AMPPD in aqueous solution by shortening the lifetime of the excited authentic emitter to 10 ps order of magnitude – three orders of magnitude shorter than the previously reported value (∼10 ns). These results shed light on the chemiluminescence dynamics of AMPPD and facilitate the design of more effective CIEEL systems. [ABSTRACT FROM AUTHOR]

Tailor-designed Au/SiO2core/shell nanoparticles are employed to enhance the efficiency of fluorescence resonance energy transfer based on quantum dots and R-phycoerythrin in solution. [ABSTRACT FROM AUTHOR]

Tailor-designed Au/SiO2core/shell nanoparticles are employed to enhance the efficiency of fluorescence resonance energy transfer based on quantum dots and R-phycoerythrin in solution. [ABSTRACT FROM AUTHOR]

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, via 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. The novel theranostic nanoplatform is constructed in such a way that the interactions between the upconversion core and the outmost scintillating shell are blocked effectively by an inert layer between them. This structural design not only enables a nearly perfect excitation energy delivery (∼100% at a spectral overlapping wavelength of ∼540 nm) from the outermost scintellating layer to the surface-anchored photosensitizers and so a maximum yield of radical oxygen species, but also achieves a strong NIR induced upconversion luminescence for imaging. Since PDT and RT attack different parts of a cancer cell, this synergy is more effective in destroying cancer than a single therapy, resulting in the reduction of the X-ray irradiation dosage. As a proof of principle, the theranostic effect is validated by in vitro and in vivo experiments, exhibiting the great potential of this sort of nanoplatform in deep cancer treatment., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Multi-sized quantum dots (QDs) donors and tailor-made gold nanorods (GNRs) are employed to form a FRET nanoplatform for homogeneous immunoassays developed for analysis of multiple virus antigens. The single GNRs/multiple QDs nanocomposite based nanosensor offers a simple and sensitive approach for multiple analytes detection in a homogeneous format., (This journal is © The Royal Society of Chemistry 2012)

LRET-based optical biosensor of an aptamer-upconversion conjugate was constructed. It is demonstrated that photosensitized breakage and damage of aptamers are eliminated by employing UCNPs as donors, and the as-designed biosensor is specific and sensitive in the detection of ATP.

The concentration quenching threshold of upconversion luminescence was broken through for the first time via a designed strategy: spatial separation of the emitter doping area., (This journal is © The Royal Society of Chemistry 2011)