07 Jul Negative staining of macromolecules
The mPrep system simplifies the preparation of macromolecular and particulate specimens for TEM.
Problems
Negative stain specimen preparation requires fine forceps to transfer filmed grids across droplets of macromolecule or particle suspensions, negative stains, and rinses. This presents microscopists with multiple challenges:
- Grids and support films are easily damaged
- Handling grids is tedious
- Grids are easily lost or mixed up
- Limited quantities of specimen solutions may be available
- Specimen and reagent solutions may evaporate, precipitate or be contaminated
- Inconsistent adsorption and staining times across multiple grids
mPrep solutions
- Encapsulated grids reduce handling and damage
- Grids with specimens may require direct handling only at the microscope
- Grids in mPrep/g capsules are always labeled
- Capsules require only 35 μl to prepare two grids
- Enclosed capsules reduce or eliminate air exposure
- Simultaneous processing assures uniform timing
DNA RecA (TEM negative stain)

Application Notes
Illustrates the preparation of macromolecular specimens for negative stain TEM using mPrep/g capsules, pipettors and Formvar®-filmed TEM grids. The example is a DNA-RecA complex, although the protocol is applicable to many other specimens. The specimen preparation and microscopy was performed in the Department of Biochemistry at the University of Wisconsin – Madison by Mr. Jay Campbell and Dr. Sindhu Chitteni-Pattu, in the laboratory of Dr. Michael M Cox.
Required
mPrep/g capsules to hold TEM grids
mPrep/f couplers to prevent introducing damaging reagents into pipettors
Pipettor (such as a Gilson P200 volume) to enable reagent pipetting into mPrep/s capsules
Recommended
Reagent reservoirs
Microwell plates
mPrep/bench to seal capsule bottoms during long reagent treatments
Gilson Pipetman Neo (P200) pipettors bundled with mPrep/g capsules.
mPrep/g Pipettor Kit single-channel
- Single-channel pipettor
- mPrep/s capsule pack
- 96 pipette tips
mPrep/g Pipettor Kit eight-channel
- Eight-channel pipettor
- mPrep/g capsule pack
- 96 pipette tips
Product Descriptions
Publications
Easier and Safer Biological Staining: High Contrast UranyLess Staining of TEM Grids using mPrep/g Capsules (Microscopy & Microanalysis 2015)
Videos
This video tutorial demonstrates how to use mPrep capsules with multi-channel pipettors and common lab ware to simultaneously deliver reagents to multiple specimens and grids. The video demonstrates TEM fixation and embedding. Reagent processing procedures are similar for all specimen types and for grids with mPrep capsules .
6 minutes 4 seconds
Instructions
Instructions for using mPrep/g capsules for grid handling and processing.
Print this 96-well plate template to organize protocols into columns and rows with a microtiter 96-well plate.
A graphical display illustrating how to load grids into mPrep/g capsules, and how to use pipettors to stain or label grids. Use this guide as a lab reference poster.
Product Descriptions
mPrep grid products
mPrep™ CPD Holder
Holds up to 6 mPrep/s or mPrep/g capsules in Tousimis® CPD apparatus
Product SKU: 33010$225.00
ASP-1000™ mPrep Automatic Specimen Processor
Programable specimen and grid preparation. Request a Quotation
Product SKU: ASP100096-well Plates – 500ul per well
96-well plates, polypropylene, round wells with U-bottom, 10/sleeve
Product SKU: 51001$39.00
12-Channel Reagent Reservoir – Single pack
12-channel reagent reservoir, polypropylene
Product SKU: 52501$7.59
mPrep/g™ Pipettor Kit eight-channel
eight-channel pipettor, mPrep/g capsule pack, 96 pipette tips
Product SKU: 43200$691.00
mPrep/g™ Pipettor Kit single-channel
single-channel pipettor, mPrep/g capsule pack, 96 pipette tips
Product SKU: 43100$376.00
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