Mar 19, 2025
Version 1
Mass photometry V.1
- Minghao Chen1,
- Yuanchang Zhao2
- 1University of California, Berkeley;
- 2UC Berkeley
Protocol Citation: Minghao Chen, Yuanchang Zhao 2025. Mass photometry. protocols.io https://dx.doi.org/10.17504/protocols.io.kqdg3keq7v25/v1
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: March 19, 2025
Last Modified: March 19, 2025
Protocol Integer ID: 124620
Keywords: ASAPCRN, mass photometry, performing mass photometry measurement, mass photometry measurement
Abstract
A protocol for performing mass photometry measurements.
Troubleshooting
Clean the highe-precision coverslips (Azer Scientific) by alternating between isopropanol and water.
Repeat the above treatment for 3 times in a bath sonicator, each 3 min.
Air dry the coverslips
Clean the gasket by alternating between isopropanol and water.
Repeat the above treatment for 3 times, without sonicatino.
Air dry the gasket.
Add 19 ul of mass photometry buffer (30 mM HEPES pH 7.4, 5 mM MgSO4 and 1 mM EGTA) to the well for autofocus
Dilute the protein sample in the mass photometry buffer to a concentration of 5–20 nM.
(Optional) For crosslinking, add 1 μL of 0.1% (v/v) glutaraldehyde in mass photometry buffer to 9uL protein sample and incubated for 10 minutes, followed by quenching the reaction with adding 10 μL of 1M Tris-HCl pH 7.4.
Prior to the measurement, perform mass calibration using a standard mix of conalbumin, aldolase, and thyroglobulin. Analyze the mass photometry profiles and fit them to multiple Gaussian peaks, with
the mean, standard deviation, and percentages calculated using DiscoverMP software (Refeyn).
Measure the protein contrast counts using Refeyn TwoMP mass photometer, with three technical replicates.