Related Experiment Video
Updated: Aug 7, 2026
Tracking Single Proteins in Lipid Bilayers Using Fluorescence Microscopy
Published on: December 12, 2025
In situ three-dimensional characterization of membrane fouling by protein suspensions using multiphoton microscopy
David J Hughes1, Zhanfeng Cui, Robert W Field
1Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ, UK.
Abstract:
Fouling of microfiltration membranes leads to severe flux declines and the need to clean or replace the membrane. In situ 3D characterization of protein fouling both on the surface and within the pores of the membrane was achieved using multiphoton microscopy. Time-lapse images of the fouled membrane were obtained for single suspensions and mixtures of fluorescently labeled bovine serum albumin and ovalbumin. Deposited protein aggregates were visible on the membrane and evidently play an important role in fouling. A combination of 3D images and resistance versus time data was used to identify the dominant fouling mechanism. Fouling is initially internally dominated, but after 1 and 15 min for ovalbumin and bovine serum albumin, respectively, the fouling becomes externally dominated. This is in good agreement with two-stage protein fouling models.
Insights
Multiphoton microscopy visualized protein fouling in microfiltration membranes. Protein aggregates drive fouling, which shifts from internal to external domination over time.
Area of Science:
- Membrane science and technology
- Biomaterials engineering
- Surface chemistry
Background:
- Membrane fouling significantly reduces microfiltration efficiency, necessitating cleaning or replacement.
- Understanding protein fouling mechanisms is crucial for optimizing membrane performance and longevity.
Purpose of the Study:
- To characterize the in situ 3D structure of protein fouling on microfiltration membranes.
- To identify the dominant fouling mechanisms and their progression over time.
Main Methods:
- Utilized multiphoton microscopy for in situ 3D imaging of fluorescently labeled protein fouling.
- Acquired time-lapse images of membranes fouled by bovine serum albumin and ovalbumin suspensions.
- Combined 3D imaging data with resistance versus time measurements.
Main Results:
- Visualized deposited protein aggregates on and within membrane pores, confirming their role in fouling.
- Observed that fouling is initially internally dominated.
- Determined that fouling transitions to externally dominated after 1 minute for ovalbumin and 15 minutes for bovine serum albumin.
Conclusions:
- Protein aggregates are key contributors to microfiltration membrane fouling.
- The fouling process exhibits a transition from internal to external domination, consistent with two-stage models.
- In situ 3D characterization provides valuable insights into fouling dynamics.
