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Functionalization of Atomic Force Microscope Cantilevers with Single-T Cells or Single-Particle for Immunological Single-Cell Force Spectroscopy
Published on: July 10, 2019
Direct observation of single particle electrostatic charging by atomic force microscopy
Matthew J Bunker1, Martyn C Davies, Michael B James
1Laboratory of Biophysics and Surface Analysis, The School of Pharmacy, University of Nottingham, Nottingham, Notts, UK.
Pharmaceutical Research
|March 22, 2007
Summary
Atomic force microscopy (AFM) offers a novel way to study electrostatic charging in pharmaceutical particles. This method quanties charge generation and dissipation influenced by relative humidity.
Area of Science:
- Pharmaceutical Science
- Surface Science
- Electrostatics
Background:
- Understanding electrostatic charging of pharmaceutical particles is crucial for drug formulation and handling.
- Traditional methods for studying particle charging have limitations in precision and direct observation.
Purpose of the Study:
- To demonstrate the utility of Atomic Force Microscopy (AFM) for direct investigation of electrostatic charging and dissipation in single pharmaceutical particles.
- To establish a novel AFM-based methodology for analyzing particle electrostatics.
Main Methods:
- Lactose particles were attached to AFM cantilevers and charged on a glass surface at low relative humidity (RH).
- Force-distance curves were recorded to measure long-range electrostatic interactions.
- Contact charging and tribocharging methods were compared, and the effect of RH on charge dissipation was studied.
Main Results:
- Tribocharging generated significantly more electrostatic charge compared to repeated local contacts.
- Increasing the relative humidity from 0.1% to 5% led to the dissipation of tribo-generated charge within 37 minutes.
Conclusions:
- AFM provides a powerful, novel approach to directly study electrostatic charging mechanisms and charge dissipation in pharmaceutical particles.
- The technique allows for quantitative comparison of charging methods and assessment of environmental factors like RH on charge stability.
