Metal–Organic Frameworks as Sensory Materials and Imaging Agents

Abstract

Metal-organic frameworks (MOFs) are a class of hybrid materials self-assembled from organic bridging ligands and metal ion/cluster connecting points. The combination of a variety of organic linkers, metal ions/clusters, and structural motifs can lead to an infinite array of new materials with interesting properties for many applications. In this Forum article, we discuss the design and applications of MOFs in chemical sensing and biological imaging. The first half of this article focuses on the development of MOFs as chemical sensors by highlighting how unique attributes of MOFs can be utilized to enhance sensitivity and selectivity. We also discuss some of the issues that need to be addressed in order to develop practically useful MOF sensors. The second half of this article focuses on the design and applications of nanoscale metal-organic frameworks (NMOFs) as imaging contrast agents. NMOFs possess several interesting attributes, such as high cargo loading capacity, ease of post-modification, tunable size and shape, and intrinsic biodegradability, to make them excellent candidates as imaging contrast agents. We discuss the use of representative NMOFs in magnetic resonance imaging (MRI), X-ray computed tomography (CT), and optical imaging (OI). Although still in their infancy, we believe that the compositional tunability and mild synthetic conditions of NMOF imaging agents should greatly facilitate their further development for clinical translation.

Photoluminescent Metal–Organic Frameworks for Gas Sensing

“…In addition, luminescence can also be generated from guest chromophore or charge transfer between the host framework and guest molecules. The diversified luminescence mechanisms make MOFs a unique platform for various luminescence applications 2, 3, 4, 26, 27, 28, 29…”

Vibrational fingerprint of the absorption properties of UiO-type MOF materials

“…Owing to the large number of both organic and inorganic building blocks available, MOFs have a high level of tunability. In combination with the large pores and high surface area, this explains why these materials are considered for many potential applications, in particular in the fields of catalysis, gas storage, chemical sensing and separation [6][7][8]. More recently, the research domain of MOFs is extended toward light-based applications, more specifically their use in photocatalysis [9,10] and as luminescent materials [11].…”

Novel Mn3[Co(CN)6]2@SiO2@Ag Core–Shell Nanocube: Enhanced Two‐Photon Fluorescence and Magnetic Resonance Dual‐Modal Imaging‐Guided Photothermal and Chemo‐therapy

“…[27][28][29] Besides, some MOFs can also serve as MRI contrast agents due to the properties of central metal ions. [ 27,30,31 ] All these make them good candidates to serve as diagnostic and therapeutic systems. Noble metals such as gold and silver have recently received great attentions for their novel capacity of controlling drug release due to surface plasmon resonance (SPR) of the noble metal nanoparticles.…”