Access this dataset on Dryad

Principal Investigator Contact Information

Carlos M. Rinaldi-Ramos
Institution: University of Florida
Email: [carlos.rinaldi@ufl.edu]

Alternate Contact Information

Ambar C. Velazquez-Albino
Email: [ambar.acva@gmail.com]

Dates of Data Collection

Data were collected throughout 2024–2025.

Funding

This work was supported by the National Institutes of Health (NIH) through the National Institute for Biomedical Imaging and Bioengineering under award number R01EB031224, the National Cancer Institute (NCI) under award R21CA263653, and the National Institute of Neurological Disorders and Stroke (NINDS) under award R21NS125089.

Related Publication

Ambar C. Velazquez-Albino, Bianca Elsea, Andrii Melnyk, Neel Eswaran, Eric D. Imhoff, Aleia G. Williams, Willem Graham, Jacqueline Anne Johnson, Charles E. Johnson, Megan M. Butala, Carlos M. Rinaldi-Ramos; Esterification synthesis of iron oxide nanoparticle tracers for magnetic particle imaging (MPI). Nanoscale 2026; 18 (5): 2625–2640. https://doi.org/10.1039/d5nr03157e

Recommended Citation for the Data Set

Ambar C. Velazquez-Albino, Bianca Elsea, Andrii Melnyk, Neel Eswaran, Eric D. Imhoff, Aleia G. Williams, Willem Graham, Jacqueline Anne Johnson, Charles E. Johnson, Megan M. Butala, Carlos M. Rinaldi-Ramos; Data for: Esterification synthesis of iron oxide nanoparticle tracers for magnetic particle imaging (MPI) [Dataset]. Dryad. doi:

Dataset Overview

This repository contains the experimental data supporting the manuscript above, which describes an esterification route for synthesizing iron oxide nanoparticle tracers for magnetic particle imaging (MPI). The deposited files fall into three groups, matching the three main experimental studies in the paper:

Per the lab's data-sharing policy, this repository includes the data used to generate the paper's figures, tables, and conclusions (raw exports and analysis-ready/derived data), plus the metadata needed to interpret them. Proprietary instrument-native files not used directly in the analysis (e.g., full native TEM acquisition folders, native FTIR instrument project files) are retained internally by the Rinaldi-Ramos Lab and are available on request; this README notes where that applies.

Synthesis Conditions Summary

Iron oxide nanoparticles were synthesized by esterification of an iron-oleate precursor with oleyl alcohol in a Schlenk-line reactor under argon, with the oleate precursor added continuously via syringe pump.

Reaction conditions relevant to each folder, cross-referenced from the manuscript's figures and results text:

*Flow rate unit conversion:* file/folder names in `(B).../FlowRate study` use volumetric pump rate (mL min⁻¹), while the manuscript reports precursor addition rate in mmolFe min⁻¹. These convert via the Fe(II) oleate concentration (0.5 M): e.g. `0.2mLperMin` = 0.1 mmolFe min⁻¹ (the 	condition identified in the manuscript as optimal). The full mapping: `0.05→0.025`, `0.2→0.1`, `0.5→0.25`, `1→0.5`, `5→2.5 mmolFe min⁻¹` — this matches the manuscript's stated tested range (0.025–2.5 mmolFe min⁻¹) exactly.

Repository Organization and Structure

(A) Fig1. Fe(II) at 290C/
├── FTIR/
│   ├── (Dat) LTE_FTIR_Aliquots.csv            # raw spectra, all aliquots
│   └── (Ana) LTE_FTIR_Aliquots_PeakSummary.csv # tracked peak positions, all aliquots
└── TEM/
    └── LTE_A{2,5,8}_{5,60,120}min_TEM.csv      # per-particle size measurements, one file per aliquot

(B) Fig2. Fe (II) T and FR study/
├── FlowRate study/
│   └── {0.05,0.2,0.5,1,5}mLperMin_TEM.csv      # per-particle size measurements, one file per flow rate
└── Temperature study/
    └── {290,320,350}C_TEM.csv                  # per-particle size measurements, one file per reaction temperature

(C) Fig3-5. Iron oleate study/
├── FTIR/
│   ├── (Dat) OleateStudy_FTIR_Aliquots.csv
│   └── (Ana) OleateStudy_FTIR_Aliquots_PeakSummary.csv
├── Mossbauer/
│   ├── Raw Data.csv                            # spectra + fits, all samples/temperatures
│   └── Fe{2,3,2_3} {293K,6K}.fit   # per-sample fit-parameter reports (7 files)
├── TEM/
│   └── Fe{2,3,2&3}_{5,15,30,45}min_TEM.csv, Fe{2,3,2&3}_final_TEM.csv  # per-particle size measurements (13 files)
├── XRD/
│   └── Fe{2,3,2&3}_XRD.csv                     # diffraction pattern + identified peaks, per sample
└── nD-PEG Coating/
    ├── MPI/
    │   ├── Analysis/
    │   │   ├── RELAX_Fe{2,3,2&3}_Summary.csv           # relaxometry summary, per tracer
    │   │   ├── MPI Serial Dilution_Data Summary.csv    # signal vs. Fe mass, all tracers
    │   │   └── MPI Line Scans_Data Summary.csv         # spatial resolution line-scan summary, all tracers
    │   └── Raw Data/
    │       ├── RELAX scans/Fe{2,3,2&3}_relax_{1,2,3}.csv   # raw relaxometer scans, triplicate per tracer
    │       └── 2D/
    │           ├── Fe{2,3,2&3}_2DSt_1mgFe_{1,2,3}.dcm      # standard 2D MPI images, triplicate per tracer
    │           ├── Serial Dilutions/Fe{2,3}(&3)/Fe*_2DSt_*ngFe.dcm  # 2D MPI images across Fe mass dilution series
    │           └── Line Scans - Resolution Phantom/Fe*_2DSt_*mm.dcm # 2D MPI images at increasing capillary separation
    └── SQUID/
        ├── Fe{2,3,2&3}_MH.dat                  # raw magnetometer output, per tracer
        └── Results Summary_MH.csv              # M vs. H summary, all tracers

List of Abbreviations

Per-Technique Documentation

FTIR ((A).../FTIR, (C).../FTIR)

• (Dat) *_FTIR_Aliquots — raw exported spectra for every aliquot in the study: wavenumber (cm⁻¹) vs. absorbance (A, unitless), one aliquot per column pair. This is the exported spectrum, not the spectrometer's native project file. Aliquots were drawn directly from the reaction and scanned to track reaction progress in real time.

• (Ana) *_FTIR_PeakSummary — tracked peak position (Wave Number, cm⁻¹) for each assigned functional group, by aliquot, used to track esterification progress over reaction time. Peak assignments (from the manuscript):

  Group	Wavenumber
  R-OH	~3227 cm⁻¹
  Ester C=O stretch	~1741 cm⁻¹
  Carboxylic acid C=O stretch (free oleic acid)	~1712 cm⁻¹
  Asymmetric COO⁻ stretch (Fe-oleate)	~1570 cm⁻¹
  Ester C-O stretch	~1241, 1175 cm⁻¹
  Alcohol C-O stretch	~1064 cm⁻¹

TEM particle sizing ((A).../TEM, (B).../*/TEM, (C).../TEM)

Each file is a per-particle table from automated image analysis of TEM micrographs, with columns:

XRD ((C).../XRD)

Each Fe{2,3,2&3}_XRD.csv contains, per sample, three paired series generated by SmartLab Studio II: Calc. data (measured diffraction pattern: 2θ in degrees vs. intensity in counts), Individual peaks (same axes, peak-fitted/smoothed pattern), and Peak bar (2θ positions of software-identified peaks, plotted as a stick pattern; Y is a constant 0 baseline for plotting).

Mössbauer spectroscopy ((C).../Mossbauer)

• Raw Data.csv — combined spectra and fits for all samples/temperatures. Columns: Xdata (velocity, mm/s), Ydata (measured transmission/counts), Yfit (overall fitted curve), Ysite#1–Ysite#4 (fitted sub-spectra for up to 4 magnetically distinct Fe sites), organized by sample (Fe 2, Fe 3, Mix) and measurement temperature (293K, 6K).
• *.fit files (7) — one per sample/temperature combination, plain-text fit reports from the CALFUN/Lorentz.f90 fitting routine. Each reports: source (Fe-57 in Rhodium), drive polarity, velocity waveform, calibration material (α-Fe foil) and calibration file, number of fitted points/parameters, and per-site fitted parameters (relative area, amplitudes, linewidths, isomer shift relative to the α-Fe calibrant, internal hyperfine field, and quadrupole shift e²qQ/2), each with fitted value, a vary/fixed flag, and a standard error.

SQUID magnetometry ((C).../nD-PEG Coating/SQUID)

• Fe{2,3,2&3}_MH.dat — raw MPMS-3 (Quantum Design) output for each tracer's magnetization-vs-field sweep, including full instrument header (hardware/firmware versions, sample mass, sample holder) and per-point columns for temperature (K), magnetic field (Oe), moment (emu) and associated diagnostics/status fields (see in-file [Data] header row for the complete column list).
• Results Summary_MH.csv — processed M–H summary per tracer: Magnetic Field (mT) vs. Magnetization normalized two ways — per mg Fe₃O₄ (Am²/kg Fe3O4) and per mg Fe (Am²/kgFe) — plus Fe mass (mg) used for normalization.
• Data were fit to the Langevin function for superparamagnetism weighted by a log-normal magnetic-diameter distribution (Chantrell et al. model) to obtain the magnetic diameter (Dm) and its geometric deviation (ln σm). Saturation magnetization (Ms) is the maximum of the M–H curve, normalized by Fe mass.
• Fe mass/concentration for normalization (applies here and to the RELAX/MPI summaries below) was determined with a 1,10-phenanthroline colorimetric assay. The raw UV-Vis absorbance data behind this assay are not part of this deposit — only the resulting Fe mass/concentration values, as used to normalize the SQUID and RELAX results, are included.

MPI ((C).../nD-PEG Coating/MPI)

• Raw Data/RELAX scans/Fe{2,3,2&3}_relax_{1,2,3}.csv — raw point-spread-function (PSF) scans from the RELAX™ module (single-channel, non-imaging), triplicate per tracer, with an instrument-generated header (operator, project/exam name, series number). Acquired at 45 kHz, 16 mT field amplitude (x-axis); 5–15 µL of sample (1–2 mgFe mL⁻¹) in a 200 µL microcentrifuge tube, centered in a custom 3D-printed holder in the scanner's field of view (FOV), scanned for 3–5 min.
• Analysis/RELAX_Fe{2,3,2&3}_Summary.csv — per-tracer summary: sample volume (µL), Fe concentration (mg/mL, from the phenanthroline assay above), Fe mass (mg), and the two headline PSF metrics from the manuscript — signal intensity (peak specific intensity, normalized by Fe mass, units mgFe⁻¹) and resolution (system-reported FWHM of the PSF peak, units mT).
• Raw Data/2D/*.dcm — 2D MPI images in DICOM format, acquired in standard multichannel mode (45 kHz for x/z axes, 5.7 T m⁻¹ gradient), reconstructed via x-space direct reconstruction with an equalization filter — i.e., these are the reconstructed/sharpened images used directly in the analysis (confirmed by the manuscript's methods), not unprocessed scanner raw output; the full native scanner output is retained internally. Organized into three experiment types:
  • Fe{2,3,2&3}_2DSt_1mgFe_{1,2,3}.dcm — standard single-concentration images, triplicate per tracer, used as the reference/baseline scan (visual comparison in the paper).
  • Serial Dilutions/Fe{2,3}(&3)/Fe*_2DSt_*ngFe.dcm — serial dilution series (25–1000 ngFe in 5 µL, triplicate capillaries, 0.8 mm ID, placed perpendicular to the FOV) used to establish the linear signal-vs.-Fe-mass response and limit of detection (LOD determined by comparison to the background signal of a water sample).
  • Line Scans - Resolution Phantom/Fe*_2DSt_*mm.dcm — two 0.8 mm-ID capillaries (5 µL / 5–10 µg each) placed parallel to the FOV at increasing separation (3.25–5 mm), used to assess spatial resolution: images analyzed as line-scan profiles (in-house MATLAB), with two signals considered "separated" once the trough between them drops below half the maximum peak signal.
• Analysis/MPI Serial Dilution_Data Summary.csv and Analysis/MPI Line Scans_Data Summary.csv — exports summarizing signal vs. Fe mass and vs. capillary separation, respectively, per tracer, corresponding to the maximum-signal ROI values extracted from the DICOM images above.