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Microcalorimetric method to assess phagocytosis: macrophage-nanoparticle interactions
M H D Kamal Al-Hallak1, Muhammad Khan Sarfraz, Shirzad Azarmi
1Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, 3126 Dentistry/Pharmacy Centre, Edmonton, Alberta, Canada T6G 2N8.
The AAPS Journal
|November 9, 2010
Summary
Isothermal microcalorimetry (ITMC) effectively detects macrophage-nanoparticle interactions by measuring thermal activity. Different nanoparticle formulations show varying interactions, with mannosylated gelatin NPs exhibiting the highest engagement.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Cell Biology
Background:
- Macrophage-nanoparticle interactions are crucial for drug delivery and toxicology.
- Accurate methods are needed to quantify these interactions, particularly phagocytosis.
- Isothermal microcalorimetry (ITMC) offers a sensitive approach to monitor cellular energetics.
Purpose of the Study:
- To evaluate isothermal microcalorimetry (ITMC) as a tool for detecting and quantifying macrophage-nanoparticle interactions.
- To investigate how different nanoparticle (NP) formulations influence macrophage interaction via phagocytosis.
- To correlate thermal activity changes with NP uptake by macrophages.
Main Methods:
- Preparation of four distinct nanoparticle formulations: uncoated poly(isobutyl cyanoacrylate) (PIBCA), polysorbate-80-coated PIBCA, gelatin, and mannosylated gelatin NPs.
- Culture of alveolar macrophages and measurement of their thermal activity using ITMC.
- Titration of NP suspensions to macrophages and calculation of relative interactive coefficients based on heat exchange.
- Control experiments using cytochalasin B (Cyto B) to inhibit phagocytosis.
Main Results:
- Significant differences in thermal activity and interactive coefficients were observed among the NP formulations.
- Mannosylated gelatin NPs showed the highest heat exchange (75.4 ± 7.5 J) and interactive coefficient (9,269 ± 630 M-1).
- Polysorbate-80-coated NPs exhibited the lowest heat exchange (15.2 ± 3.4 J) and interactive coefficient (890 ± 120 M-1).
- Cyto B significantly inhibited the macrophage response, confirming the link between thermal activity and phagocytosis.
- Results were consistent with flow cytometry data.
Conclusions:
- Isothermal microcalorimetry (ITMC) is a valuable tool for monitoring biological responses to nano-sized dosage forms.
- ITMC can differentiate macrophage-nanoparticle interactions based on NP formulation, offering insights into phagocytosis.
- This technique aids in understanding cellular energetics and advancing the development of colloidal drug delivery systems.
