Platinum-Doped Dendritic Structure as a Phosphorescent Label for Bacteria in Two-Photon Excitation Microscopy

Molina, Noemí; Cnudde, Marvin; Guadix, Juan Antonio; Pérez‐Pomares, José M.; Strassert, Cristian A.; Vida, Yolanda; Pérez‐Inestrosa, Ezequiel

doi:10.1021/acsomega.9b00639

Cited by 9 publications

(6 citation statements)

References 27 publications

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“…Cyclometalated transition metal complexes have been extensively studied in the last decades, mainly due to the broad range of applications derived from their photophysical properties. The utilization of coordination compounds has shown promising results in the fields of bioimaging, − optoelectronics, − photodynamic therapy, , and optical sensors, , among many others. While there are numerous compounds reported with d 6 -configured ions presenting nearly octahedral geometries, such as Ir(III) − or Re(I) complexes, , Pd(II)- and Pt(II)-derived species have also shown a particular collection of interesting features.…”

Section: Introductionmentioning

confidence: 99%

Room-Temperature Phosphorescence from Pd(II) and Pt(II) Complexes as Supramolecular Luminophores: The Role of Self-Assembly, Metal–Metal Interactions, Spin–Orbit Coupling, and Ligand-Field Splitting

et al. 2023

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The synthesis as well as the structural and photophysical characterization of two isoleptic bis-cyclometalated Pt(II) and Pd(II) complexes, namely [PtL] and [PdL], bearing a tailored dianionic tetradentate ligand (L 2− ) are reported. The isostructural character and intermolecular interactions of [PtL] and [PdL] were assessed by NMR spectroscopy and X-ray diffraction analysis. Both complexes show fully ligand-controlled aggregation, demonstrating that a judicious molecular design can tune the photophysical properties. In fact, by introduction of fluorine atoms on defined positions and methoxy groups on complementary sites, metal−metal interactions can be forced by a head-to-tail stacking. Hence, [PtL] shows luminescence from metal-perturbed ligandcentered or from metal-metal-to-ligand charge-transfer triplet states in diluted solutions, in frozen glasses and in crystals, with high photoluminescence quantum yields and long lifetimes in the microsecond range. At room temperature (RT) in concentrated fluid solutions, the palladium analogue [PdL] surprisingly emits luminescence from aggregated species involving supramolecular interactions. Time-resolved photoluminescence and transient absorption spectroscopies demonstrated that ultrafast intersystem crossing occurs for both metals, which outruns any competitive relaxation pathway from the photoexcited singlet state. Furthermore, we demonstrate that the radiationless deactivation can be suppressed in frozen glassy matrices at 77 K and by intermolecular interactions in fluid solutions at RT. In both cases and as indicated by density functional theory calculations, the lowest emissive state acts as an energy trap from which the thermal population of dissociative states with formal occupation of an antibonding Pdcentered 4d x 2 −y 2 orbital is suppressed. This occurs as the energy gap between the emissive and the dark states surpasses kT.

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Section: Introductionmentioning

confidence: 99%

Room-Temperature Phosphorescence from Pd(II) and Pt(II) Complexes as Supramolecular Luminophores: The Role of Self-Assembly, Metal–Metal Interactions, Spin–Orbit Coupling, and Ligand-Field Splitting

et al. 2023

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“…We have also lately shown that the variation of monodentate coligands with variable bulk, ,− degree of coplanarization, and atomic number can drastically influence the structural and photophysical properties of monomeric and aggregated molecular entities with Pt(II) centers. Moreover, ancillary ligands with dendrimeric anchors enabled us to label planktonic bacteria with Pt(II)-based phosphorescence, whereas the adsorption of Pt(II) complexes with suitably substituted tridentate luminophores allowed us to decorate proteins and gel-forming nanoclays …”

Section: Introductionmentioning

confidence: 99%

Conjugated Pt(II) Complexes as Luminescence-Switch-On Reporters Addressing the Microenvironment of Bacterial Biofilms

et al. 2021

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In this work, the synthesis, structural and photophysical characterization of six phosphorescent H 2 O-soluble Pt(II) complexes are reported while addressing their emission maxima, photoluminescence quantum yields (Φ L ), lifetimes (τ), aggregation tendency, and microenvironment sensitivity as a function of the substitution pattern on the main tridentate luminophore. Different ancillary ligands, namely, a trisulfonated phosphane and maltohexaose-conjugated pyridines (with or without amide bridges), were introduced and evaluated for the realization of switch-on-photoluminescent labels reporting on the microenvironment sensed in biofilms of Gram + and Gram − models, namely, Staphylococcus aureus and Escherichia coli. With the aid of confocal luminescence micro(spectro)scopy, we observed that selected complexes specifically interact with the biofilms while leaving planktonic cells unlabeled. By using photoluminescence lifetime imaging microscopy, excited-state lifetimes within S. aureus biofilms were measured. The photoluminescence intensities were drastically boosted, and the excited state lifetimes were significantly prolonged upon binding to the viscous biofilm matrix, mainly due to the suppression of radiationless deactivation pathways upon shielding from physical quenching processes, such as interactions with solvent molecules and 3 O 2 . The best performances were attained for non-aggregating complexes with maltohexaose targeting units and without amide bridges. Notably, in the absence of the maltodextrin, a hydrophobic adamantyl moiety suffices to attain a sizeable labeling capacity. Moreover, photoluminescence studies showed that selected complexes can also effectively interact with E. coli biofilms, where the bacterial cells are able to partially uptake the maltodextrin-based agents. In summary, the herein introduced concepts enable the development of specific biofilm reporters providing spatial resolution as well as lifetime-and spectrum-based readouts. Considering that most theragnostic agents reported so far mainly address metabolically active bacteria at the surface of biofilms but without reaching cells deeply immersed in the matrix, a new platform with a clear structure-property correlation is provided for the early detection of such bacterial arrays.

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“…1308,1309 Strassert, Vida, Perez-Inestrosa, and co-workers have developed a dendritic platinum(II) complex (706) for labeling bacteria. 1310 The terminal amino groups of the dendritic skeleton are critical to the binding of the complex to the anionic bacterial cell surface via hydrogen bonding and electrostatic interactions.…”

Section: Bacterial Envelopementioning

confidence: 99%

Shining New Light on Biological Systems: Luminescent Transition Metal Complexes for Bioimaging and Biosensing Applications

Lee,

2024

Chem. Rev.

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Luminescence imaging is a powerful and versatile technique for investigating cell physiology and pathology in living systems, making significant contributions to life science research and clinical diagnosis. In recent years, luminescent transition metal complexes have gained significant attention for diagnostic and therapeutic applications due to their unique photophysical and photochemical properties. In this Review, we provide a comprehensive overview of the recent development of luminescent transition metal complexes for bioimaging and biosensing applications, with a focus on transition metal centers with a d 6 , d 8 , and d 10 electronic configuration. We elucidate the structure−property relationships of luminescent transition metal complexes, exploring how their structural characteristics can be manipulated to control their biological behavior such as cellular uptake, localization, biocompatibility, pharmacokinetics, and biodistribution. Furthermore, we introduce the various design strategies that leverage the interesting photophysical properties of luminescent transition metal complexes for a wide variety of biological applications, including autofluorescence-free imaging, multimodal imaging, organelle imaging, biological sensing, microenvironment monitoring, bioorthogonal labeling, bacterial imaging, and cell viability assessment. Finally, we provide insights into the challenges and perspectives of luminescent transition metal complexes for bioimaging and biosensing applications, as well as their use in disease diagnosis and treatment evaluation.

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Platinum-Doped Dendritic Structure as a Phosphorescent Label for Bacteria in Two-Photon Excitation Microscopy

Cited by 9 publications

References 27 publications

Room-Temperature Phosphorescence from Pd(II) and Pt(II) Complexes as Supramolecular Luminophores: The Role of Self-Assembly, Metal–Metal Interactions, Spin–Orbit Coupling, and Ligand-Field Splitting

Room-Temperature Phosphorescence from Pd(II) and Pt(II) Complexes as Supramolecular Luminophores: The Role of Self-Assembly, Metal–Metal Interactions, Spin–Orbit Coupling, and Ligand-Field Splitting

Conjugated Pt(II) Complexes as Luminescence-Switch-On Reporters Addressing the Microenvironment of Bacterial Biofilms

Shining New Light on Biological Systems: Luminescent Transition Metal Complexes for Bioimaging and Biosensing Applications

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