Themed collection Dalton Discussion 15: Metal ions in medical imaging

Welcome to this Dalton Transactions themed issue including papers from Dalton Discussion 15 – Metal ions in medical imaging: optical, radiopharmaceutical and MRI contrast.

This perspective outlines strategies towards the development of MR imaging probes that our lab has explored.

The use of radiometal isotopes in positron emission tomography: a new success story in nuclear imaging?

A survey of the current status and challenges for the use of radionuclides of the elements in nuclear medicine.

The creation of the most emissive series of europium complexes is traced and examples given of their use in imaging.

New sulfonamides and their metal complexes are reported, with a focus on porphyrin derivatives for simultaneous cellular optical imaging, radiolabelling and Carbonic Anhydrase inhibition capabilities.

Highly paramagnetic coordination clusters with a {Fe₁₀Ln₁₀} core are used as NMR relaxation agents with a first application in a biofilm study.

Cyclen-based ligands containing two picolinate pendant arms form Gd³⁺ complexes remarkably stable and inert with respect to metal ion dissociation.

Biscyclam derivatives containing either a BODIPY moiety or a precursor for ¹⁸F radiolabelling have been prepared for CXCR4 imaging.

Time-gated Tb-to-dye FRET imaging for the investigation of E- and N-cadherin expression on different model cell lines.

The FPR1 antagonist cFLFLFK is conjugated to a tetraglycine chelate, and radiolabelled with ^99mTc. In vitro binding assays demonstrate that the compound, ^99mTc.cFLFLFK, is a useful tool for non-invasive imaging of leukocyte recruitment.

A series of new gadolinium complexes have been synthesised to test the design of dual-modal probes that can display a change in fluorescence or relaxivity response upon zinc binding. By an iterative change in parameters of the probes, the compounds give insight into the design protocols required for successful imaging of zinc ions.

The synthesis of the first technetium-99m and rhenium-188 complexes with two pendant bisphosphonate groups is described, along with their in vivo use in imaging the skeleton and arterial calcification.

The synthesis of a new pyrene-containing Fischer carbene complex is described.

[M(CO)₃]⁺ (M = Tc/Re) complexes with tridentate ligands with a stilbene functional group bind to amyloid-β plaques associated with Alzheimer's Disease.

Four new phosphorescent biscyclometallated iridium(III) ethylenediamine complexes were designed as bioimaging and visualization reagents.

Four new red BODIPY–gold(I) theranostic compounds were synthesized.

In pursuit of the goal of a molecular theranostic suitable for use as a PET radiotracer and a photosensitiser for PDT, a novel ⁶⁸Ga radiolabelled peptide–porphyrin conjugate targeting the α₆β₁-integrin has been developed.

Two europium and terbium luminescent bio-probes whose luminescence can be sensitized by a two-photon sensitisation process have been designed and the proof-of-concept of biphotonic multiplexing experiment is described.

The self-assembling of two macrocyclic Gd-chelates results in a small-sized dimeric system characterized by a remarkably high relaxivity, r₁.

A tris(hydroxypyridinone) chelator coordinates the PET imaging isotope, ⁸⁹Zr⁴⁺, rapidly and quantitatively under ambient conditions, but a ⁸⁹Zr-labelled tris(hydroxypyridinone)-immunoconjugate is not stable to in vivo demetallation.

Sarcophagine ligands with isothiocyanate functional groups were conjugated to trastuzumab, radiolabelled with ⁶⁴Cu and used to image HER2-positive tumours using PET.