📋 SUMMARY

Research published in ACS Nano (2024) embedded multimodal near-infrared nanosensors in 3D Petri Dish® spheroids to enable real-time monitoring of oxygen gradients. The study revealed previously unknown "inverted" oxygenation patterns in certain spheroid types, advancing understanding of hypoxia in tumor biology.

🔬 Biosensor Technology

Live Microscopy of Multicellular Spheroids with Multimodal Near-Infrared Nanoparticles Reveals Differences in Oxygenation Gradients

ACS Nano · 2024

Cite: ACS Nano (2024).

RESEARCH OVERVIEW

This study presents multimodal near-infrared (MMIR) nanoparticles containing O₂-sensitive metalloporphyrin dyes embedded in biocompatible polymer for quantitative oxygenation monitoring in living spheroids. The nanosensors enable both fluorescence ratio and phosphorescence lifetime measurements on conventional microscopes, revealing complex oxygen gradient patterns that differ significantly between spheroid types.

🔑 Key Findings

  • NIR nanosensors enable real-time, non-invasive oxygen monitoring in intact 3D spheroids
  • Discovered "inverted" oxygenation gradients with higher core oxygen in certain spheroid types
  • Compatible with conventional fluorescence microscopes for accessible quantitative imaging
  • Revealed cell-type-specific metabolic differences between HCT116 cancer and dental pulp stem cell spheroids

🧫 3D Petri Dish® Application

The 3D Petri Dish® micro-mold platform was used to generate uniform multicellular spheroids for nanosensor embedding and oxygenation studies.

  • Uniform Spheroid Generation: 3D Petri Dish® produced consistent spheroid sizes critical for reproducible oxygenation measurements.
  • Nanosensor Integration: MMIR nanoparticles were incorporated during spheroid formation in 3D Petri Dish® micro-molds.
  • Live Monitoring: The platform enabled long-term culture with continuous oxygen gradient tracking.
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FREQUENTLY ASKED QUESTIONS

Q: How do NIR nanosensors measure oxygen in spheroids?
A: The nanosensors contain O₂-sensitive metalloporphyrin dyes that change their phosphorescence lifetime based on local oxygen concentration, enabling quantitative mapping of oxygenation gradients throughout the spheroid.
Q: Why is monitoring oxygen gradients in spheroids important?
A: Oxygen gradients in 3D Petri Dish® spheroids mimic in vivo tumor hypoxia conditions, which critically influence drug resistance, gene expression, and cell behavior in cancer research.