Multifunctional, Tunable Metal–Organic Framework Materials Platform for Bioimaging Applications

Abstract

Herein, we describe a novel multifunctional metal-organic framework (MOF) materials platform that displays both porosity and tunable emission properties as a function of the metal identity (Eu, Nd, and tuned compositions of Nd/Yb). Their emission collectively spans the deep red to near-infrared (NIR) spectral region (∼614-1350 nm), which is highly relevant for in vivo bioimaging. These new materials meet important prerequisites as relevant to biological processes: they are minimally toxic to living cells and retain structural integrity in water and phosphate-buffered saline. To assess their viability as optical bioimaging agents, we successfully synthesized the nanoscale Eu analog as a proof-of-concept system in this series. In vitro studies show that it is cell-permeable in individual RAW 264.7 mouse macrophage and HeLa human cervical cancer tissue culture cells. The efficient discrimination between the Eu emission and cell autofluorescence was achieved with hyperspectral confocal fluorescence microscopy, used here for the first time to characterize MOF materials. Importantly, this is the first report that documents the long-term conservation of the intrinsic emission in live cells of a fluorophore-based MOF to date (up to 48 h). This finding, in conjunction with the materials' very low toxicity, validates the biocompatibility in these systems and qualifies them as promising for use in long-term tracking and biodistribution studies.

Carbon Dots Based Nanoscale Covalent Organic Frameworks for Photodynamic Therapy

“…Recently, porous materials, especially metal-organic frameworks (MOFs), are widely used in drug delivery and bioimaging due to the various structures and multiple functions. [1][2][3][4][5][6][7][8] Relatively, covalent organic frameworks (COFs) formed purely from organic monomers are less explored in biomedical fields due to the large size, low aqueous dispersivity, and poor cell permeability, although they possess unique characters of potential biodegradability in vivo and the low density. [9][10][11] Most of the reported COFs are made from aromatic molecules with several functional groups, such as amino, aldehyde, or boric acid.…”

Amorphous-to-crystalline transition and photoluminescence switching in guest-absorbing metal–organic network thin films

“…30 This is of exclusive interest in bioimaging, bioassays, catalysis, NIR laser systems, and photon-upconversion. [30][31][32][33][34] Here, we show excitingly that our ALD/MLD-grown Nd-TP thin films show photoluminescence switching upon aMOF-to-crystalline transition achieved through water absorption.…”

Enhancing Van der Waals Interactions of Functionalized UiO‐66 with Non‐polar Adsorbates: The Unique Effect of para Hydroxyl Groups

“…To further support the positive effect of the (2,5‐dihydroxyterephthalate (dobdc) linker on O 2 adsorption, another series of isoreticular MOFs were made using the dobdc linker with several rare earth metals. The synthesis and characterization of these analogues was recently reported elsewhere . The XRD patterns exhibit a related structure as the Zr based UiO‐66 MOFs.…”