Nanoscale Metal–Organic Frameworks for Ratiometric Oxygen Sensing in Live Cells

Abstract

We report the design of a phosphorescence/fluorescence dual-emissive nanoscale metal–organic framework (NMOF), R-UiO, as an intracellular oxygen (O2) sensor. R-UiO contains a Pt(II)-porphyrin ligand as an O2-sensitive probe and a Rhodamine-B isothiocyanate ligand as an O2-insensitive reference probe. It exhibits good crystallinity, high stability, and excellent ratiometric luminescence response to O2 partial pressure. In vitro experiments confirmed the applicability of R-UiO as an intracellular O2 biosensor. This work is the first report of a NMOF-based intracellular oxygen sensor and should inspire the design of ratiometric NMOF sensors for other important analytes in biological systems.

Metal–Organic Frameworks for Biomedical Applications

“…Lin and co‐workers reported a phosphorescent/fluorescent dual‐emitting ratiometric NMOF biosensor (R‐UiO), consisting of an oxygen‐sensitive probe (Pt‐5,15‐di( p ‐benzoato)porphyrin, DBP‐Pt ligand) and an oxygen‐insensitive probe (rhodamine B isothiocyanate‐conjugated quaterphenyldicarboxylate, QPDC ligand) for intracellular O 2 quantitative determination (Figure 9c). 71 The prepared biosensor showed high stability, good biocompatibility, and efficient cellular uptake, ensuring the feasibility of intracellular O 2 detection. Under hypoxia, normoxia, and aerated conditions, the intracellular O 2 levels measured and imaged by R‐UiO were 5.29 ± 0.12, 4.45 ± 0.09, and 2.80 ± 0.06 mmHg, respectively, which was consistent with the three different O 2 conditions (Figure 9d).…”

Two‐Dimensional Metal–Organic Framework Nanosheets

“…Recently, the preparation of nanoscale MOF crystals with controlled size, shape, and morphology has become an emerging topic, as conventional bulk MOFs cannot completely fulfill the specific requirements for many applications . Particularly, for biological related applications, MOFs with smaller sizes are required in order to facilitate their internalization into cells, such as in biomedical imaging, drug delivery, and biosensing . Nanoscale MOFs also have a higher surface area than that of their bulk counterparts, resulting in their performance improvement in separation, catalysis, and sensing .…”

Controlled Nucleation and Controlled Growth for Size Predicable Synthesis of Nanoscale Metal–Organic Frameworks (MOFs): A General and Scalable Approach

“…Bytaking advantages of the nanosize,t he potential uses of metal-organic frameworks (MOFs) are broadened by nano-MOFs, [1] including application in biomedical sensing and imaging, [2] functional membranes, [3] thin film devices, [4] cancer therapy [5] and drug delivery. [6] Thes ize of nanomaterials is critical for their properties and utility.Asmall change of size within nanoscale (say,t ens of nanometers) may have ad ecisive impact on some properties of nanomaterials.…”