Extreme Ultraviolet Reflection Spectroscopy of Lanthanides and Actinides Using a High Harmonic Generation Light Source.

Absorption spectroscopy probing transitions from shallow-core d and f orbitals in lanthanides and actinides reveals information about bonding and the electronic structure in compounds containing these elements. However, spectroscopy in this photon energy range is challenging because of the limited availability of light sources and extremely short penetration depths. In this work, we address these challenges using a tabletop extreme ultraviolet (XUV), ultrafast, laser-driven, high harmonic generation light source, which generates femtosecond pulses in the 40-140 eV range. We present reflection spectroscopy measurements at the N4,5 (i.e., predominantly 4d to 5f transitions) and O4,5 (i.e., 5d to 5f transitions) absorption edges on several lanthanide and uranium oxide crystals. We compare these results to density functional theory calculations to assign the electronic transitions and predict the spectra for other lanthanides. This work paves the way for laboratory-scale XUV absorption experiments for studying crystalline and molecular f-electron systems, with applications ranging from surface chemistry, photochemistry, and electronic or chemical structure determination to nuclear forensics.

Superoxide Radicals in Uranyl Peroxide Solids: Lasting Signatures Identified by Electron Paramagnetic Resonance Spectroscopy.

U(VI) peroxide phases (studtite and meta-studtite) are found throughout the nuclear fuel cycle and exist as corrosion products in high radiation fields. Peroxides are part of a family of reactive oxygen species (ROS) that include hydroperoxyl and superoxide species and are produced during alpha radiolysis of water. While U(VI) peroxides have been thoroughly investigated, the incorporation and stability of ROS species within studtite have not been validated. In the current study, electron paramagnetic resonance (EPR) spectroscopy was used to identify the presence of free radicals within a series of U(VI) peroxide samples containing depleted, highly enriched, and natural uranium. Density functional theory calculations indicated that the predicted EPR signals matched well with a superoxide (O2 -⋅) species incorporated into the studtite structure, confirming the presence of ROS in the material. Further analysis of samples that were synthesized between 1945 and 2023 indicated that there is a correlation between the radical signal and the product of specific activity multiplied by age of the sample.

Lineage-specific intolerance to oncogenic drivers restricts histological transformation.

Lung adenocarcinoma (LUAD) and small cell lung cancer (SCLC) are thought to originate from different epithelial cell types in the lung. Intriguingly, LUAD can histologically transform into SCLC after treatment with targeted therapies. In this study, we designed models to follow the conversion of LUAD to SCLC and found that the barrier to histological transformation converges on tolerance to Myc, which we implicate as a lineage-specific driver of the pulmonary neuroendocrine cell. Histological transformations are frequently accompanied by activation of the Akt pathway. Manipulating this pathway permitted tolerance to Myc as an oncogenic driver, producing rare, stem-like cells that transcriptionally resemble the pulmonary basal lineage. These findings suggest that histological transformation may require the plasticity inherent to the basal stem cell, enabling tolerance to previously incompatible oncogenic driver programs.

Intervalence Charge Transfer in Nonbonding, Mixed-Valence, Homobimetallic Ytterbium Complexes.

There are several reports of compounds containing lanthanide ions in two different formal oxidation states; however, there are strikingly few examples of intervalence charge transfer (IVCT) transitions observed for these complexes, with those few occurrences limited to extended solids rather than molecular species. Herein, we report the synthesis, characterization, and computational analysis for a series of ytterbium complexes including a mixed-valence Yb25+ complex featuring a remarkably short Yb···Yb distance of 2.9507(8) Å. In contrast to recent reports of short Ln···Ln distances attributed to bonding through 5d orbitals, the formally Yb25+ complex presented here displays clear localization of Ln2+ and Ln3+ character and yet still displays an IVCT in the visible spectrum. These results demonstrate the ability to tune the electronic structure of formally mixed oxidation state lanthanide complexes: the high exchange stabilization of the Yb2+ 4f14 configuration disfavors the formation of a 5d1 bonding configuration, and the short metal-metal distance enforced by the ligand framework allows for the first observed lanthanide IVCT in a molecular system.

Diabetes Mellitus and Total Ankle Arthroplasty Complications.

BACKGROUND: Postoperative infection, aseptic loosening, and perioperative medical complications after total ankle arthroplasty (TAA) are all devastating problems. While previous studies have shown diabetes as a risk factor predisposing patients to postoperative complications, not all literature supports this association following TAA. The goal of this study is to determine if diabetes influences midterm outcomes following TAA. METHODS: An insurance database was utilized to identify patients undergoing TAA for ankle arthritis with a concurrent diagnosis of diabetes based on Current Procedural Terminology (CPT) and International Classification of Diseases, Ninth Revision (ICD-9) and Tenth Revision (ICD-10), diagnosis and procedure codes from 2010 to 2021. The postoperative outcomes of all-cause revision, periprosthetic joint infection (PJI), septic revision, and aseptic revision were compared between patients with and without diabetes with a minimum 2-year follow-up using Kaplan-Meier and multivariate Cox proportional hazards analyses. Patient demographics, comorbidities, and Charlson Comorbidity Index were analyzed via univariate and multivariate analysis. RESULTS: The study population included 8317 patients, 345 (4.1%) of whom had a concurrent diabetes diagnosis, who underwent TAA. After multivariate Cox proportional hazards analysis, the 5-year cumulative incidence of being coded as having PJI was 7.3% in patients with known diabetes compared to 3.9% in patients without known diabetes, with a 95% increased risk (hazard ratio [HR] 1.95, 95% CI 1.15-3.30, P = .01). Patients with diabetes also demonstrated a 5-year cumulative incidence of septic revision of 1.4% compared to 0.4% in those without, with a 363% increased risk (HR 4.63, 95% CI 1.22-17.52, P = .02). However, there was no difference in the 5-year cumulative incidence of all-cause revision TAA with 4.6% in patients with diabetes and 4.3% in those without (HR 1.29, 95% CI 0.69-2.44, P = .42). CONCLUSION: In this database, the 5-year risk of PJI and septic revision was higher among patients with diabetes compared to those without, but cumulative incidence of all-cause revision TAA was not different between groups. LEVEL OF EVIDENCE: Level III, retrospective cohort database study.

Influence of Linker Identity on the Photochemistry of Uranyl-Organic Frameworks.

While uranyl-based metal-organic frameworks (MOFs) boast impressive photocatalytic abilities, significant questions remain regarding their excitation pathways and methods to fine-tune their performance due to the lack of information regarding heterogeneous uranyl catalysis. Herein, we investigated how linker identity and photoexcitation impact uranyl photocatalysis when the uranyl coordination environment remains constant. Toward this end, we prepared three uranyl-based MOFs (NU-1301, NU-1307, and ZnTCPP-U2) and then examined the structural and photochemical properties of each through X-ray diffraction, X-ray absorption, and photoluminescence. We then correlated our observations to the photocatalytic performance for fluorination of cyclooctane. The excitation profile from NU-1301 and NU-1307 exhibited spin-forbidden linker transitions and uranyl vibronic progressions, with uranyl excitation and emission being most dominant in NU-1301. Consequently, NU-1301 was a more active photocatalyst than NU-1307. In contrast, the excitation profile from ZnTCPP-U2 contained transitions associated with the porphyrin linker exclusively. Photocatalytic activity from ZnTCPP-U2 significantly underperformed in comparison to that of the other two MOFs. These data suggest that linkers' photophysical properties can be used to predict the photocatalytic behavior of uranyl-containing MOFs.

Exploring Differences in Lanthanide Excited State Reactivity Using a Simple Example: The Photophysics of La and Ce Thenoyltrifluoroacetone Complexes.

A series of four lanthanide thenoyltrifluoroacetone (TTA) complexes consisting of two f0 (La3+ and Ce4+) and two f1 (Ce3+) complexes was examined using steady-state and time-resolved spectroscopic techniques. The wide range of spectroscopic techniques presented herein have enabled us to discern the nature of the excited states (charge transfer, CT vs ligand localized, LL) as well as construct a Jablonski diagram for detailing the excited state reactivity within the series of molecules. The wavelength and excitation power dependence for these series of complexes are the first direct verification for the presence of simultaneous competing, noninteracting CT and LL excited states. Additionally, a computational framework is described that can be used to support spectroscopic assignments as a guide for future studies. Finally, the relationship between the obtained photophysics and possible photochemical separation mechanisms is described.

Structure and Dynamics of NaCl/KCl/CaCl2-EuCln (n = 2, 3) Molten Salts.

Modern molten salt reactor design and the techniques of electrorefining spent nuclear fuels require a better understanding of the chemical and physical behavior of lanthanide/actinide ions with different oxidation states dissolved in various solvent salts. The molecular structures and dynamics that are driven by the short-range interactions between solute cations and anions and long-range solute and solvent cations are still unclear. In order to study the structural change of solute cations caused by different solvent salts, we performed first-principles molecular dynamics simulations in molten salts and extended X-ray absorption fine structure (EXAFS) measurements for the cooled molten salt samples to identify the local coordination environment of Eu2+ and Eu3+ ions in CaCl2, NaCl, and KCl. The simulations reveal that with the increasing polarizing the outer sphere cations from K+ to Na+ to Ca2+, the coordination number (CN) of Cl- in the first solvation shell increases from 5.6 (Eu2+) and 5.9 (Eu3+) in KCl to 6.9 (Eu2+) and 7.0 (Eu3+) in CaCl2. This coordination change is validated by the EXAFS measurements, in which the CN of Cl- around Eu increases from 5 in KCl to 7 in CaCl2. Our simulation shows that the fewer Cl- ions coordinated to Eu leads to a more rigid first coordination shell with longer lifetime. Furthermore, the diffusivities of Eu2+/Eu3+ are related to the rigidity of their first coordination shell of Cl-: the more rigid the first coordination shell is, the slower the solute cations diffuse.

Submitochondrial Protein Translocation Upon Stress Inhibits Thermogenic Energy Expenditure.

Mitochondria-rich brown adipocytes dissipate cellular fuel as heat by thermogenic energy expenditure (TEE). Prolonged nutrient excess or cold exposure impair TEE and contribute to the pathogenesis of obesity, but the mechanisms remain incompletely understood. Here we report that stress-induced proton leak into the matrix interface of mitochondrial innermembrane (IM) mobilizes a group of proteins from IM into matrix, which in turn alter mitochondrial bioenergetics. We further determine a smaller subset that correlates with obesity in human subcutaneous adipose tissue. We go on to show that the top factor on this short list, acyl-CoA thioesterase 9 (ACOT9), migrates from the IM into the matrix upon stress where it enzymatically deactivates and prevents the utilization of acetyl-CoA in TEE. The loss of ACOT9 protects mice against the complications of obesity by maintaining unobstructed TEE. Overall, our results introduce aberrant protein translocation as a strategy to identify pathogenic factors. One-Sentence Summary: Thermogenic stress impairs mitochondrial energy utilization by forcing translocation of IM-bound proteins into the matrix.

LKB1-Dependent Regulation of TPI1 Creates a Divergent Metabolic Liability between Human and Mouse Lung Adenocarcinoma.

KRAS is the most frequently mutated oncogene in human lung adenocarcinomas (hLUAD), and activating mutations frequently co-occur with loss-of-function mutations in TP53 or STK11/LKB1. However, mutation of all three genes is rarely observed in hLUAD, even though engineered comutation is highly aggressive in mouse lung adenocarcinoma (mLUAD). Here, we provide a mechanistic explanation for this difference by uncovering an evolutionary divergence in the regulation of triosephosphate isomerase (TPI1). In hLUAD, TPI1 activity is regulated via phosphorylation at Ser21 by the salt inducible kinases (SIK) in an LKB1-dependent manner, modulating flux between the completion of glycolysis and production of glycerol lipids. In mice, Ser21 of TPI1 is a Cys residue that can be oxidized to alter TPI1 activity without a need for SIKs or LKB1. Our findings suggest this metabolic flexibility is critical in rapidly growing cells with KRAS and TP53 mutations, explaining why the loss of LKB1 creates a liability in these tumors. SIGNIFICANCE: Utilizing phosphoproteomics and metabolomics in genetically engineered human cell lines and genetically engineered mouse models (GEMM), we uncover an evolutionary divergence in metabolic regulation within a clinically relevant genotype of human LUAD with therapeutic implications. Our data provide a cautionary example of the limits of GEMMs as tools to study human diseases such as cancers. This article is highlighted in the In This Issue feature, p. 799.

Photochemical separation of plutonium from uranium.

Plutonium-based technologies would benefit if chemical hazards for purifying plutonium were reduced. One critical processing step where improvements could be impactful is the adjustment of plutonium oxidation-states during separations. This transformation often requires addition of redox agents. Unfortunately, many of the redox agents used previously cannot be used today because their properties are deemed incompatible with modern day processing facilities and waste stream safety requirements. We demonstrated herein that photochemistry can be used as an alternative to those chemical agents. We observed that (1) Pu4+ → Pu3+ and UO22+ → U4+ photoreduction proceeded in HCl(aq) and HNO3(aq) and (2) photogenerated Pu3+(aq) and U4+(aq) could be separated using anion exchange chromatography (high yield, >90%; good separation factor, 322).

Oxidizing Americium(III) with Sodium Bismuthate in Acidic Aqueous Solutions.

Historic perspectives describing f-elements as being redox "inactive" are fading. Researchers continue to discover new oxidation states that are not as inaccessible as once assumed for actinides and lanthanides. Inspired by those contributions, we studied americium(III) oxidation in aqueous media under air using NaBiO3(s). We identified selective oxidation of Am3+(aq) to AmO22+(aq) or AmO21+(aq) could be achieved by changing the aqueous matrix identity. AmO22+(aq) formed in H3PO4(aq) (1 M) and AmO21+(aq) formed in dilute HCl(aq) (0.1 M). These americyl products were stable for weeks in solution. Also included is a method to recover 243Am from the americium and bismuth mixtures generated during these studies.

Advancing the Am Extractant Design through the Interplay among Planarity, Preorganization, and Substitution Effects.

Advancing the field of chemical separations is important for nearly every area of science and technology. Some of the most challenging separations are associated with the americium ion Am(III) for its extraction in the nuclear fuel cycle, 241Am production for industrial usage, and environmental cleanup efforts. Herein, we study a series of extractants, using first-principle calculations, to identify the electronic properties that preferentially influence Am(III) binding in separations. As the most used extractant family and because it affords a high degree of functionalization, the polypyridyl family of extractants is chosen to study the effects of the planarity of the structure, preorganization of coordinating atoms, and substitution of various functional groups. The actinyl ions are used as a structurally simplified surrogate model to quickly screen the most promising candidates that can separate these metal ions. The down-selected extractants are then tested for the Am(III)/Eu(III) system. Our results show that π interactions, especially those between the central terpyridine ring and Am(III), play a crucial role in separation. Adding an electron-donating group onto the terpyridine backbone increases the binding energies to Am(III) and stabilizes Am-terpyridine coordination. Increasing the planarity of the extractant increases the binding strength as well, although this effect is found to be rather weak. Preorganizing the coordinating atoms of an extractant to their binding configuration as in the bound metal complex speeds up the binding process and significantly improves the kinetics of the separation process. This conclusion is validated by the synthesized 1,2-dihydrodipyrido[4,3-b;5,6-b]acridine (13) extractant, a preorganized derivative of the terpyridine extractant, which we experimentally showed was four times more effective than terpyridine at separating Am3+ from Eu3+ (SFAm/Eu ∼ 23 ± 1).

Synthesis, solid-state, solution, and theoretical characterization of an "in-cage" scandium-NOTA complex.

Developing chelators that strongly and selectively bind rare-earth elements (Sc, Y, La, and lanthanides) represents a longstanding fundamental challenge in inorganic chemistry. Solving these challenges is becoming more important because of increasing use of rare-earth elements in numerous technologies, ranging from paramagnets to luminescent materials. Within this context, we interrogated the complexation chemistry of the scandium(III) (Sc3+) trication with the hexadentate 1,4,7-triazacyclononane-1,4,7-triacetic acid (H3NOTA) chelator. This H3NOTA chelator is often regarded as an underperformer for complexing Sc3+. A common assumption is that metalation does not fully encapsulate Sc3+ within the NOTA3- macrocycle, leaving Sc3+ on the periphery of the chelate and susceptible to demetalation. Herein, we developed a synthetic approach that contradicted those assumptions. We confirmed that our procedure forced Sc3+ into the NOTA3- binding pocket by using single crystal X-ray diffraction to determine the Na[Sc(NOTA)(OOCCH3)] structure. Density functional theory (DFT) and 45Sc nuclear magnetic resonance (NMR) spectroscopy showed Sc3+ encapsulation was retained when the crystals were dissolved. Solution-phase and DFT studies revealed that [Sc(NOTA)(OOCCH3)]1- could accommodate an additional H2O capping ligand. Thermodynamic properties associated with the Sc-OOCCH3 and Sc-H2O capping ligand interactions demonstrated that these capping ligands occupied critical roles in stabilizing the [Sc(NOTA)] chelation complex.

Spectroscopic and electrochemical characterization of a Pr4+ imidophosphorane complex and the redox chemistry of Nd3+ and Dy3+ complexes.

The molecular tetravalent oxidation state for praseodymium is observed in solution via oxidation of the anionic trivalent precursor [K][Pr3+(NP(1,2-bis-tBu-diamidoethane)(NEt2))4] (1-Pr(NP*)) with AgI at -35 °C. The Pr4+ complex is characterized in solution via cyclic voltammetry, UV-vis-NIR electronic absorption spectroscopy, and EPR spectroscopy. Electrochemical analyses of [K][Ln3+(NP(1,2-bis-tBu-diamidoethane)(NEt2))4] (Ln = Nd and Dy) by cyclic voltammetry are reported and, in conjunction with theoretical modeling of electronic structure and oxidation potential, are indicative of principal ligand oxidations in contrast to the metal-centered oxidation observed for 1-Pr(NP*). The identification of a tetravalent praseodymium complex in in situ UV-vis and EPR experiments is further validated by theoretical modeling of the redox chemistry and the UV-vis spectrum. The latter study was performed by extended multistate pair-density functional theory (XMS-PDFT) and implicates a multiconfigurational ground state for the tetravalent praseodymium complex.

Whispering gallery mode resonators in continuous flow: spectral assignments and sensing with monodisperse microspheres.

Whispering gallery mode resonator (WGMR) microspheres yield highly structured optical spectra that are extremely sensitive to their environment and are of intense interest for use in a variety of sensing applications. Many efforts to leverage the unique sensitivities of WGMRs have relied on stringent experimental requirements to correlate specific spectral shifts/changes to an analyte/stimulus such as (1) precise positional knowledge, (2) reference spectra for each microsphere, and (3) high mechanical stability. Consequently, these factors can hinder adequate mixing or incorporation of analytes and can create challenges for remote sensing. This work describes a continuous flow technique for measuring whispering gallery mode (WGM) spectra of dye-doped microspheres suspended in solution and an accompanying analysis scheme that can extract the local refractive index without a priori knowledge of the microsphere size and position and without a reference spectrum. This measurement technique and analysis scheme was shown to accurately measure the refractive index of a range of alcohol and saline solutions down to a few thousandths of a refractive index unit (RIU). Additionally, a spectral clustering algorithm was applied to the fit results of two batches of microspheres suspended in water and was able to accurately assign spectra back to either batch of microspheres.

Association of Bleeding Disorders and Risk of Complications Following Open Reduction and Internal Fixation of the Ankle.

BACKGROUND: Open reduction and internal fixation (ORIF) of the ankle is a common procedure performed to correct ankle fractures in many different patient populations. Diabetes, peripheral vascular disease, and osteoporosis have been identified as risk factors for postoperative complications following surgery for ankle fractures. To date, there have not been any studies evaluating postoperative outcomes in patients with bleeding disorders undergoing operative treatment for ankle fractures. The aim of this study was to determine the postoperative complication rate following ORIF of the ankle in patients with a bleeding disorder vs those without a bleeding disorder. METHODS: From 2006 to 2018, patients undergoing operative treatment for ankle fracture were identified in the National Surgical Quality Improvement Program database. Two patient cohorts were defined: patients with a bleeding disorder and patients without a bleeding disorder. Patients who underwent either inpatient or outpatient ORIF of the ankle were included in this study. In this analysis, demographics, medical comorbidities, and postoperative complications variables were assessed between the 2 cohorts. Bivariate and multivariate analyses were performed. RESULTS: Of 10 306 patients undergoing operative treatment for ankle fracture, 9909 patients (96.1%) had no bleeding disorder whereas 397 patients (3.9%) had a bleeding disorder. Following adjustment on multivariate analysis, compared to patients who did not have a bleeding disorder, those with a bleeding disorder had an increased risk of any postoperative complications (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.05-2.08, P = .024), requirement for postoperative blood transfusion (OR 2.86, 95% CI 1.53-5.36, P = .001), and extended length of hospital stay greater than 5 days (OR 1.46, 95% CI 1.10-1.93, P = .010). CONCLUSION: Patients with bleeding disorders are associated with increased risk of postoperative complications following ORIF for ankle fractures. Determining patient risk factors and creating optimal preoperative and perioperative management plans in patients with bleeding disorders undergoing ORIF can be beneficial in reducing postoperative complications, improving patient outcomes, and reducing overall morbidity. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Understanding the Photochemical Properties of Polythiophene Polyelectrolyte Soft Aggregates with Sodium Dodecyl Sulfate for Antimicrobial Activity.

The threat of antibiotic-resistant bacteria is an ever-increasing problem in public health. In this report, we examine the photochemical properties with a proof-of-principle biocidal assay for a novel series of regio-regular imidazolium derivative poly-(3-hexylthiophene)/sodium dodecyl sulfate (P3HT-Im/SDS) materials from ultrafast sub-ps dynamics to µs generation of reactive oxygen species (ROS) and 30 min biocidal reactivity with Escherichia coli (E. coli). This broad series encompassing pure P3HT-Im to cationic, neutral, and anionic P3HT-Im/SDS materials are all interrogated by a variety of techniques to characterize the physical material structure, electronic structure, and antimicrobial activity. Our results show that SDS complexation with P3HT-Im results in aggregate materials with reduced ROS generation and light-induced anti-microbial activity. However, our characterization reveals that the presence of non-aggregated or lightly SDS-covered polymer segments is still capable of ROS generation. Full encapsulation of the P3HT-Im polymer completely deactivates the light killing pathway. High SDS concentrations, near and above critical micelle concentration, further deactivate all anti-microbial activity (light and dark) even though the P3HT-Im regains its electronic properties to generate ROS.

Using molten salts to probe outer-coordination sphere effects on lanthanide(III)/(II) electron-transfer reactions.

Controlling structure and reactivity by manipulating the outer-coordination sphere around a given reagent represents a longstanding challenge in chemistry. Despite advances toward solving this problem, it remains difficult to experimentally interrogate and characterize outer-coordination sphere impact. This work describes an alternative approach that quantifies outer-coordination sphere effects. It shows how molten salt metal chlorides (MCln; M = K, Na, n = 1; M = Ca, n = 2) provided excellent platforms for experimentally characterizing the influence of the outer-coordination sphere cations (Mn+) on redox reactions accessible to lanthanide ions; Ln3+ + e1- → Ln2+ (Ln = Eu, Yb, Sm; e1- = electron). As a representative example, X-ray absorption spectroscopy and cyclic voltammetry results showed that Eu2+ instantaneously formed when Eu3+ dissolved in molten chloride salts that had strongly polarizing cations (like Ca2+ from CaCl2) via the Eu3+ + Cl1- → Eu2+ + ½Cl2 reaction. Conversely, molten salts with less polarizing outer-sphere M1+ cations (e.g., K1+ in KCl) stabilized Ln3+. For instance, the Eu3+/Eu2+ reduction potential was >0.5 V more positive in CaCl2 than in KCl. In accordance with first-principle molecular dynamics (FPMD) simulations, we postulated that hard Mn+ cations (high polarization power) inductively removed electron density from Lnn+ across Ln-Cl⋯Mn+ networks and stabilized electron-rich and low oxidation state Ln2+ ions. Conversely, less polarizing Mn+ cations (like K1+) left electron density on Lnn+ and stabilized electron-deficient and high-oxidation state Ln3+ ions.

ThIV-Desferrioxamine: characterization of a fluorescent bacterial probe.

Diversifying our ability to guard against emerging pathogenic threats is essential for keeping pace with global health challenges, including those presented by drug-resistant bacteria. Some modern diagnostic and therapeutic innovations to address this challenge focus on targeting methods that exploit bacterial nutrient sequestration pathways, such as the desferrioxamine (DFO) siderophore used by Staphylococcus aureus (S. aureus) to sequester FeIII. Building on recent studies that have shown DFO to be a versatile vehicle for chemical delivery, we show proof-of-principle that the FeIII sequestration pathway can be used to deliver a potential radiotherapeutic. Our approach replaces the FeIII nutrient sequestered by H4DFO+ with ThIV and made use of a common fluorophore, FITC, which we covalently bonded to DFO to provide a combinatorial probe for simultaneous chelation paired with imaging and spectroscopy, H3DFO_FITC. Combining insight provided from FITC-based imaging with characterization by NMR spectroscopy, we demonstrated that the fluorescent DFO_FITC conjugate retained the ThIV chelation properties of native H4DFO+. Fluorescence microscopy with both [Th(DFO_FITC)] and [Fe(DFO_FITC)] complexes showed similar uptake by S. aureus and increased intercellular accumulation as compared to the FITC and unchelated H3DFO_FITC controls. Collectively, these results demonstrate the potential for the newly developed H3DFO_FITC conjugate to be used as a targeting vector and bacterial imaging probe for S. aureus. The results presented within provide a framework to expand H4DFO+ and H3DFO_FITC to relevant radiotherapeutics (like 227Th).