ABSTRACT
We have created unique near-infrared (NIR)-emitting nanoscale metal-organic frameworks (nano-MOFs) incorporating a high density of Yb(3+) lanthanide cations and sensitizers derived from phenylene. We establish here that these nano-MOFs can be incorporated into living cells for NIR imaging. Specifically, we introduce bulk and nano-Yb-phenylenevinylenedicarboxylate-3 (nano-Yb-PVDC-3), a unique MOF based on a PVDC sensitizer-ligand and Yb(3+) NIR-emitting lanthanide cations. This material has been structurally characterized, its stability in various media has been assessed, and its luminescent properties have been studied. We demonstrate that it is stable in certain specific biological media, does not photobleach, and has an IC50 of 100 µg/mL, which is sufficient to allow live cell imaging. Confocal microscopy and inductively coupled plasma measurements reveal that nano-Yb-PVDC-3 can be internalized by cells with a cytoplasmic localization. Despite its relatively low quantum yield, nano-Yb-PVDC-3 emits a sufficient number of photons per unit volume to serve as a NIR-emitting reporter for imaging living HeLa and NIH 3T3 cells. NIR microscopy allows for highly efficient discrimination between the nano-MOF emission signal and the cellular autofluorescence arising from biological material. This work represents a demonstration of the possibility of using NIR lanthanide emission for biological imaging applications in living cells with single-photon excitation.
Subject(s)
Lanthanoid Series Elements/chemistry , Metal Nanoparticles/chemistry , Spectroscopy, Near-Infrared/methods , Ytterbium/chemistry , Animals , Crystallization , HeLa Cells , Humans , Lanthanoid Series Elements/pharmacokinetics , Metal Nanoparticles/ultrastructure , Mice , Microscopy, Confocal , Microscopy, Electron, Scanning , Microscopy, Fluorescence , NIH 3T3 Cells , Photons , Polyvinyl Chloride/analogs & derivatives , Polyvinyl Chloride/chemistry , Polyvinyl Chloride/pharmacokinetics , Spectroscopy, Fourier Transform Infrared , Thermogravimetry , X-Ray Diffraction , Ytterbium/pharmacokineticsABSTRACT
We demonstrate the conceptual advantage of using metal-organic frameworks (MOFs) for the creation of a polymetallic material that contains several different near-IR-emitting lanthanide cations and operates as a barcode material with unique luminescence properties. By choosing the ratio of lanthanide salts used during the synthesis, we can control the ratio of lanthanide cations present in the resulting material. We have demonstrated that the emission intensity of each of the different lanthanide cations is proportional to its amount in the MOF crystal, resulting in unique spectroscopic barcodes that depend on the lanthanide cation ratios and compositions.
Subject(s)
Electronic Data Processing/methods , Lanthanoid Series Elements/chemistry , Luminescent Agents/chemistry , Organometallic Compounds/chemistry , Electronic Data Processing/instrumentation , Luminescent Measurements , Materials Testing , Models, Molecular , Molecular Structure , Spectroscopy, Near-Infrared/methodsABSTRACT
The design of metal-organic frameworks (MOFs) incorporating near-infrared emitting ytterbium cations and organic sensitizers allows for the preparation of new materials with tunable and enhanced photophysical properties.
Subject(s)
Organometallic Compounds/chemistry , Ytterbium/chemistry , Cations/chemistry , Crystallography, X-Ray , Molecular Structure , Physical Phenomena , Spectroscopy, Near-InfraredABSTRACT
Metallic nanoparticles of different sizes, shapes and compositions are being avidly explored as materials for next-generation biological labels, therapeutic agents, 'artificial viruses' and diagnostic probes. Gold nanoparticles especially, are making a major impact in these areas, owing in large part to their ease of functionality, low toxicity and unique optical properties. In particular, gold nanoparticles are having a major role in the development of highly sensitive and selective assays for biologically relevant molecules. Some of the assays for nucleic acids and proteins developed in the last 10 years outperform established methods and may soon find routine use in hospital settings.
Subject(s)
Biosensing Techniques/methods , Gold/chemistry , Metal Nanoparticles/chemistry , Nanotechnology/methods , Adenosine/analysis , Adenosine/chemistry , Biosensing Techniques/instrumentation , Nanotechnology/instrumentation , Nucleic Acids/analysis , Nucleic Acids/chemistry , Reproducibility of ResultsABSTRACT
This study details a modular and general synthesis of a new class of molecules consisting of cruciform pi-systems. The key to synthesizing these molecules was an unprecedented double Staudinger cyclization. Once formed, these rigid compounds assemble into ordered monolayer films on metal and metal oxide surfaces to orient their conjugated, bis-phenyloxazole subunits upright. This surface orientation is enforced by the external phenyl substituents that are out of the ring plane, thus preventing the prone conformation.
