Metal Peptide Conjugates in Cell and Tissue Imaging and Biosensing

Abstract

Metal complex luminophores have seen dramatic expansion in application as imaging probes over the past decade. This has been enabled by growing understanding of methods to promote their cell permeation and intracellular targeting. Amongst the successful approaches that have been applied in this regard is peptide-facilitated delivery. Cell-permeating or signal peptides can be readily conjugated to metal complex luminophores and have shown excellent response in carrying such cargo through the cell membrane. In this article, we describe the rationale behind applying metal complexes as probes and sensors in cell imaging and outline the advantages to be gained by applying peptides as the carrier for complex luminophores. We describe some of the progress that has been made in applying peptides in metal complex peptide-driven conjugates as a strategy for cell permeation and targeting of transition metal luminophores. Finally, we provide key examples of their application and outline areas for future progress.

Targeting Peptides: The New Generation of Targeted Drug Delivery Systems

“…Based on their excellent in vivo properties, several bifunctional chelators, typically containing a macrocyclic core such as DOTA, DTPA, NOTA, and TETA, have been labeled with radiometals and used in diagnostic imaging. The covalent conjugation to the peptide is frequently achieved at the N-terminus or at the C-terminus via a C-terminal lysine, allowing very thermodynamically stable and kinetically inert complexes [63,[131][132][133].…”

Peptide-Based Materials That Exploit Metal Coordination

“…Peptides and metals have been combined in various ways. For instance, peptide-metal conjugates have been applied to biosensing [121]. Peptides have been used for the sensing of metals too [122].…”

Dual FGFR-targeting and pH-activatable ruthenium–peptide conjugates for targeted therapy of breast cancer

“…Ru, Au, Fe, Co, Ir, and Re) as cytotoxic agents. 19,[39][40][41][42][43][44] We have previously designed a tumor-targeting DDS based on the ruthenium-cyclopentadienyl complex [RuCp(PPh 3 )(2,2′bipy)][CF 3 SO 3 ] (TM34) combined with FGFR-targeting pep-tides. TM34 is highly potent in vitro against several cancer cell lines, in particular, breast cancer cells (MFC-7 and MDA-MB-231), [45][46][47][48] and the peptide was envisaged as the vector to selectively deliver paved the way for the exploration of FGFR inhibitors as potential targeted therapeutic agents.…”