Lanthanide Metal–Organic Frameworks for Multispectral Radioluminescent Imaging

Abstract

In this report, we describe the X-ray luminescent properties of two lanthanide-based nanoscale metal−frameworks (nMOFs) and their potential as novel platforms for optical molecular imaging techniques such as X-ray excited radioluminescence (RL) imaging. Upon X-ray irradiation, the nMOFs display sharp tunable emission peaks that span the visible to nearinfrared spectral region (∼400−700 nm) based on the identity of the metal (Eu, Tb, or Eu/Tb). Surface modification of the nMOFs with polyethylene glycol (PEG) resulted in nanoparticles with enhanced aqueous stability that demonstrated both cyto-and hemo-compatibility important prerequisites for biological applications. Importantly, this is the first report to document and investigate the radioluminescent properties of lanthanide nMOFs. Taken together, the observed radioluminescent properties and low in vitro toxicity demonstrated by the nMOFs render them promising candidates for in vivo translation.

High‐Z Metal–Organic Frameworks for X‐ray Radiation‐Based Cancer Theranostics

“…In 2020, Neufeld et al. proposed europium and terbium‐based 1,4‐benzenedicarboxylic acid (BDC) nMOFs as molecular contrast probes for X‐ray luminescence imaging [17] . Following X‐ray excitation, all nMOFs displayed bright radioluminescence within the visible spectrum derived from the lanthanide metal (Figure 4 a).…”

“… (a) RL emission spectrum and (b) RL imaging of TbBDC‐PEG, EuBDC‐PEG, and EuxTbxBDC‐PEG nMOF concentrations (mg mL −1 ) in H 2 O. (c) In vitro RLI of CT26 cell pellets under X‐ray excitation of (i) blank cells and cells incubated with (ii) EuBDC‐PEG, (iii) TbBDC‐PEG, and (iv) EuxTbxBDC‐PEG nMOFs for 24 h. Adapted with permission [17] . Copyright 2020, American Chemical Society.…”

“…In 2020, Neufeld et al proposed europiuma nd terbium-based 1,4-benzenedicarboxylic acid (BDC) nMOFs as molecular contrast probesf or X-ray luminescence imaging. [17] Following X-ray excitation, all nMOFsd isplayed bright radioluminescence within the visible spectrum derived from the lanthanide metal ( Figure 4a). For example, examination of the EuBDC emission spectra reveals characteristic Eu 3 + emission at approximately 582, 593, 616, 654, and 702 nm ( Figure 4b).…”

“…Anticancer efficacyi na4T1 murine breast cancerm odel demon- In vitro RLI of CT26 cell pellets under X-ray excitationo f(i) blank cells and cellsi ncubated with (ii)EuBDC-PEG, (iii)TbBDC-PEG,and (iv) EuxTbxBDC-PEG nMOFs for 24 h. Adapted with permission. [17] Copyright 2020, American Chemical Society. strated that the combinedt reatment of intravenously administrated Hf-TCPP with RT and PDT significantly improved tumor regression,d emonstrating the potentialo fh igh-Z nMOFs for enhancing RT.T his carboxylate nMOF is hydrolyticallys ensitive and decomposes over time to permitefficient clearance, unlike inorganic high-Z NPs Metal-organic frameworks for RT and X-ray photodynamic therapy Tumor hypoxia and lowt issue penetration of light are often cited as limitations of PDT,w hich relies on direct excitation of ap hotosensitizer in the presence of molecular oxygen to produce atherapeutic effect.…”

Pan‐lanthanides method for plastic doping, application in photophysics, and scintillation with proof of photoelectric event occurrences

“…The Lanthanides row (referred to as a whole using Ln symbol) is a family of heavy elements that sees a lot of interest in research. It is common to see studies on their chemistry (eg, catalysis, 1‐3 synthesis 4 ), their photophysics (narrow emission, 5,6 visible, and infrared emission 7,8 ), their applications in materials science (plastic labeling, 9 crystals 10‐15 ), and in nuclear sciences (scintillator, 16‐19 beta detection, 20 and radioluminescence imaging 21,22 ). Gathering expertise from these fields, our group earlier focused on using gadolinium in a plastic scintillator 23 as a thermal neutron absorber 24,25 .…”