Dataset Information

Low Efficiency Upconversion Nanoparticles for High-Resolution Coalignment of Near-Infrared and Visible Light Paths on a Light Microscope.

ABSTRACT: The combination of near-infrared (NIR) and visible wavelengths in light microscopy for biological studies is increasingly common. For example, many fields of biology are developing the use of NIR for optogenetics, in which an NIR laser induces a change in gene expression and/or protein function. One major technical barrier in working with both NIR and visible light on an optical microscope is obtaining their precise coalignment at the imaging plane position. Photon upconverting particles (UCPs) can bridge this gap as they are excited by NIR light but emit in the visible range via an anti-Stokes luminescence mechanism. Here, two different UCPs have been identified, high-efficiency micro540-UCPs and lower efficiency nano545-UCPs, that respond to NIR light and emit visible light with high photostability even at very high NIR power densities (>25?000 Suns). Both of these UCPs can be rapidly and reversibly excited by visible and NIR light and emit light at visible wavelengths detectable with standard emission settings used for Green Fluorescent Protein (GFP), a commonly used genetically encoded fluorophore. However, the high efficiency micro540-UCPs were suboptimal for NIR and visible light coalignment, due to their larger size and spatial broadening from particle-to-particle energy transfer consistent with a long-lived excited state and saturated power dependence. In contrast, the lower efficiency nano-UCPs were superior for precise coalignment of the NIR beam with the visible light path (?2 ?m versus ?8 ?m beam broadening, respectively) consistent with limited particle-to-particle energy transfer, superlinear power dependence for emission, and much smaller particle size. Furthermore, the nano-UCPs were superior to a traditional two-camera method for NIR and visible light path alignment in an in vivo Infrared-Laser-Evoked Gene Operator (IR-LEGO) optogenetics assay in the budding yeast Saccharomyces cerevisiae. In summary, nano-UCPs are powerful new tools for coaligning NIR and visible light paths on a light microscope.

SUBMITTER: Sundaramoorthy S

PROVIDER: S-EPMC5720688 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature

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Low Efficiency Upconversion Nanoparticles for High-Resolution Coalignment of Near-Infrared and Visible Light Paths on a Light Microscope.

Sundaramoorthy Sriramkumar S Garcia Badaracco Adrian A Hirsch Sophia M SM Hirsch Sophia M SM Park Jun Hong JH Davies Tim T Dumont Julien J Shirasu-Hiza Mimi M Kummel Andrew C AC Canman Julie C JC

ACS applied materials & interfaces 20170221 9

The combination of near-infrared (NIR) and visible wavelengths in light microscopy for biological studies is increasingly common. For example, many fields of biology are developing the use of NIR for optogenetics, in which an NIR laser induces a change in gene expression and/or protein function. One major technical barrier in working with both NIR and visible light on an optical microscope is obtaining their precise coalignment at the imaging plane position. Photon upconverting particles (UCPs) ...[more]

PMID: 28221018

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Project description:Photodynamic therapy (PDT) has been widely applied in the clinic for the treatment of various types of cancer due to its precise controllability, minimally invasive approach and high spatiotemporal accuracy as compared with conventional chemotherapy. However, the porphyrin-based photosensitizers (PSs) used in clinics generally suffer from aggregation-caused reductions in the generation of reactive oxygen species (ROS) and limited tissue penetration because of visible light activation, which greatly hampers their applications for the treatment of deep-seated tumors. Methods: We present a facile strategy for constructing a NIR-regulated cancer theranostic nanoplatform by encapsulating upconversion nanoparticles (UCNPs) and a luminogen (2-(2,6-bis((E)-4-(phenyl(40-(1,2,2-triphenylvinyl)-[1,10-biphenyl]-4-yl)amino)styryl)-4H-pyran-4-ylidene)malononitrile, TTD) with aggregation-induced emission (AIEgen) characteristics using an amphiphilic polymer, and further conjugating cyclic arginine-glycine-aspartic acid (cRGD) peptide to yield UCNP@TTD-cRGD NPs. We then evaluated the bioimaging and anti-tumor capability of the UCNP@TTD-cRGD NPs under NIR light illumination in an in vitro three-dimensional (3D) cancer spheroid and in a murine tumor model, respectively. Results: With a close match between the UCNP emission and absorption of the AIEgen, the synthesized NPs could efficiently generate ROS, even under excitation through thick tissues. The NIR-regulated UCNP@TTD-cRGD NPs that were developed could selectively light up the targeted cancer cells and significantly inhibit tumor growth during the NIR-regulated PDT treatment as compared with the cells under white light excitation. Conclusion: In summary, the synthesized UCNP@TTD-cRGD NPs showed great potential in NIR light-regulated photodynamic therapy of deep-seated tumors. Our study will inspire further exploration of novel theranostic nanoplatforms that combine UCNPs and various AIEgen PSs for the advancement of deep-seated tumor treatments with potential clinical translations.

Project description:Clinical requirements have necessitated the development of biomedical nanomaterials that can be implanted into tissues or bodies. Physiological regulation can be achieved in these nanomaterials through external light. The combination of nanomaterials with infrared optics can be termed optogenetics. The low autofluorescence of upconversion nanoparticles (UCNPs) has several applications in the biological field. For optogenetics applications, UCNPs with high fluorescence performance and photostability can solve the penetration depth problem. NaYF4:Yb,Tm nanocrystals with controllable sizes, shapes, and compositions were synthesized using a rapid coprecipitation method in organic solvent. UCNPs using single crystal nanoparticles provide higher chemical stability than those using amorphous phase. However, because UCNPs are usually capped with hydrophobic ligands, it is particularly important to prepare biocompatible UCNPs with specific molecular recognition capabilities. Surface modification and subsequent functionalization are essential for the application of inorganic nanomaterials in the biological environment and are arousing increasing research interest. Due to the high biocompatibility and high loading of materials, mesoporous silica and amine groups were selected as the best candidates. Expression of plasmid DNA in vivo and transfection efficiency were determined by fluorescence microscopy and flow cytometry. The MTT assay was used to evaluate the particle biocompatibility; the results showed that UCNP@mSiO2 has great biocompatibility. Additionally, at neutral pH, the cell surface is negatively charged. Therefore, the surface is functionalized with amino groups and can be electrostatically bound to DNA. Finally, UCNP@mSiO2-NH2 as a vector was applied in live cells by loading DNA; according to the results, DNA-UCNPs were successfully transfected in the primary cells, and NaYF4:Yb,Tm@mSiO2-NH2-DNA were observed to have good transfection efficiency by flow cytometry. It is expected that this work will provide a different method from the traditional adenovirus method and improve the immune response and side effects caused by adenovirus.

Dataset Information

Low Efficiency Upconversion Nanoparticles for High-Resolution Coalignment of Near-Infrared and Visible Light Paths on a Light Microscope.

Publications

Low Efficiency Upconversion Nanoparticles for High-Resolution Coalignment of Near-Infrared and Visible Light Paths on a Light Microscope.

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