L.R. White Embedding Media is a low-viscosity, hydrophilic acrylic embedding resin used for light microscopy, electron microscopy, histochemistry, and immunohistochemistry. Its approximately 8 cP viscosity supports rapid infiltration of dehydrated specimens.
The resin can be thermally polymerized directly from the bottle or cured at room temperature or under cooled conditions with L.R. White Accelerator. Sections can be prepared for routine light microscopy or cut ultrathin for electron microscopy.
For workflows requiring both light and electron microscopy from the same specimen, Poly/LEM Fixative is available for combination LM/EM specimen preparation.
Key Properties
- Hydrophilic acrylic embedding resin
- Used for light and electron microscopy
- Suitable for histochemistry and immunohistochemistry workflows
- Viscosity: approximately 8 cP
- Single-component resin for thermal polymerization
- Room-temperature and cold curing available with L.R. White Accelerator
- Supports light-microscopy and ultrathin electron-microscopy sectioning
- Block hardness specification: 61–81
- Package size: 500 g
- Storage: 4°C
Applications
Light Microscopy
L.R. White can be used to prepare plastic-embedded specimens for light microscopy. Larger block faces can be sectioned at approximately 1–5 µm using a microtome and blade suitable for plastic sections.
Electron Microscopy
The same embedding resin can be used for ultrathin section preparation for electron microscopy. Lead citrate, uranyl acetate, and other established heavy-metal staining procedures may be used with L.R. White sections.
Histochemistry & Immunohistochemistry
The hydrophilic acrylic resin is used in histochemical and immunohistochemical workflows. Processing and staining conditions should be selected for the tissue, stain, antibody, and section thickness being used.
Combined Light & Electron Microscopy
L.R. White supports preparation of specimens for both light and electron microscopy from the same embedding system. For combination LM/EM fixation, see Poly/LEM Fixative.
Polymerization & Processing Considerations
- Thermal curing can be performed with resin directly from the bottle
- Thermal polymerization is performed at 60–65°C for approximately 12–20 hours
- Oxygen should be excluded during thermal polymerization because it can inhibit complete curing
- For room-temperature curing, add 20 µL of L.R. White Accelerator to 10 mL of resin immediately before use
- Accelerated resin typically polymerizes in approximately 10–20 minutes at room temperature
- Cold polymerization at 0–4°C can be used to reduce the exotherm during accelerated curing
- Do not use acetone during specimen dehydration because it can inhibit free-radical polymerization of L.R. White
Use graded alcohols for dehydration before infiltration. Infiltration time depends on specimen size and density; the L.R. White procedure uses resin-only infiltration rather than mixtures of resin and dehydration solvent.
Sectioning & Staining
- Use a microtome designed for plastic sections
- Small block faces can be sectioned below 1 µm with an appropriate plastic-sectioning knife
- Larger block faces can be sectioned at approximately 1–5 µm
- Ultrathin sections can be prepared for electron microscopy
- Light-microscopy sections of approximately 2 µm and thicker can be stained with many routine histological stains
- Alcohol-based stains can soften the surrounding resin and should be used for the shortest practical exposure time
For rapid staining of thin plastic sections, Multiple Stain Solution can be used according to its applicable staining procedure.
Application Tips
- Allow only the amount of refrigerated resin required for the procedure to reach room temperature
- Return the stock resin to 4°C promptly after dispensing
- Measure L.R. White Accelerator accurately with a calibrated micropipette
- Avoid excess accelerator, which can produce rapid polymerization, excessive heat, and bubbling
- Maintain oxygen-limited conditions during thermal curing
- Use graded alcohols rather than acetone for dehydration before embedding
Handling & Storage
- Store at 4°C
- Keep the container tightly closed when not in use
- Minimize exposure to atmospheric moisture and oxygen
- Use under a chemical fume hood or with appropriate laboratory ventilation
- Wear protective gloves and eye protection during handling
Why Choose Polysciences?
Trusted by 6,000+ Researchers Worldwide
Cited in Thousands of Peer-Reviewed Studies
U.S. Manufacturing & Global Distribution
Reliable Delivery to 40+ Countries
FAQ
Click a question to expand.
1. What is L.R. White resin?
L.R. White is a low-viscosity, hydrophilic acrylic embedding resin used for light microscopy, electron microscopy, histochemistry, and immunohistochemistry.
2. Can L.R. White be used for both light and electron microscopy?
Yes. L.R. White can be sectioned for light microscopy and for ultrathin electron microscopy, allowing both approaches to be performed using the same embedding resin.
3. What is the viscosity of L.R. White?
L.R. White has a viscosity of approximately 8 cP. Its low viscosity supports infiltration of dehydrated tissue specimens.
4. How is L.R. White polymerized?
L.R. White can be thermally polymerized directly from the bottle at 60–65°C or polymerized at room temperature or under cooled conditions using L.R. White Accelerator.
5. How much L.R. White Accelerator should be used?
For room-temperature curing, add 20 µL of accelerator to 10 mL of L.R. White resin immediately before use and mix thoroughly.
6. How long does accelerated L.R. White take to polymerize?
With the specified accelerator ratio, polymerization typically occurs in approximately 10–20 minutes at room temperature.
7. Can acetone be used to dehydrate specimens before L.R. White embedding?
No. Acetone acts as a free-radical scavenger and can inhibit L.R. White polymerization. Use graded alcohol dehydration instead.
8. What section thicknesses can be prepared from L.R. White blocks?
Small block faces can be sectioned below 1 µm with appropriate plastic-sectioning equipment, while larger blocks can be sectioned at approximately 1–5 µm. Ultrathin sections can also be prepared for electron microscopy.
9. Can routine histological stains be used with L.R. White sections?
Yes. Sections approximately 2 µm and thicker can be stained with many routine histological stains. Alcohol-based staining solutions can soften the surrounding resin, so exposure times should be kept as short as practical.
10. How should L.R. White be stored?
Store at 4°C with the container tightly closed. Limiting exposure to oxygen and atmospheric moisture helps maintain reliable polymerization.
11. What package size is available?
Available in a 500 g package. For larger quantities, use the bulk-quote option.
Safety & Documentation
Use L.R. White with appropriate laboratory ventilation, protective gloves, and eye protection. Review the Safety Data Sheet (SDS) for current handling and safety information, the Product Specification for current product specifications, Technical Data Sheet 305 for L.R. White and L.R. Gold information, and Technical Data Sheet 305A for the detailed L.R. White embedding procedure.
