PolyTransport Buffer is a non-fixative transport medium for excised and biopsy tissue awaiting fixation, freezing, or allocation to histology and microscopy workflows. It is designed to maintain specimen pH and osmolarity during transport for 24–48 hours while allowing subsequent selection of the appropriate fixation or processing method.
The buffer has a specified pH of 7.2–7.6 and contains a cryoprotectant and a membrane-stabilizing component. The formulation is intended to limit bacterial growth and autolysis during transport. Specimens can be transferred directly from PolyTransport Buffer to the selected fixative or freezing procedure without an intermediate rinse.
Key Properties
- Product number: 24311
- Product type: Non-fixative tissue transport medium
- pH specification: 7.2–7.6
- Recommended specimen thickness: Approximately 1–1.5 mm
- Specimen transport: Cool to approximately 4°C after placement in buffer
- Extended transport: Maintain specimens at 0–4°C
- Stored specimens: Maintain at 4°C until fixation or freezing
- Maximum holding time for routine paraffin processing: 48 hours
- Electron microscopy specimens: Preferably processed within 24 hours
- Contains a cryoprotectant to assist in limiting ice-crystal formation during rapid freezing
- Contains a membrane-stabilizing component intended to limit membrane lysis
- Formulated to inhibit bacterial growth and autolysis during transport
- No rinse required before fixation or rapid freezing
- Available sizes: 250 mL and 500 mL
- Product storage: 20°C
Applications
Specimen Transport Prior to Fixation
PolyTransport Buffer provides a temporary non-fixative medium for excised or biopsy specimens when immediate fixation is not appropriate or when tissue must be divided among different downstream procedures.
Routine Paraffin Histology
Specimens transported in PolyTransport Buffer may be transferred directly to the selected fixative before routine paraffin processing. Tissue intended for routine paraffin histology should not remain in the transport medium for more than 48 hours.
Frozen-Section Workflows
The formulation contains a cryoprotectant that assists in limiting ice-crystal formation during rapid freezing. Specimens may be transferred without rinsing to a freezing medium such as PolyFreeze Tissue Freezing Medium.
Immunohistochemistry & Histochemistry
PolyTransport Buffer may be used for temporary specimen transport before fixation or processing for immunohistochemical and histochemical procedures. Specimens should proceed to the selected fixation or processing method within the recommended 24–48 hour interval.
Electron Microscopy
PolyTransport Buffer may be used as a temporary non-fixative transport medium when electron microscopy specimens cannot be placed immediately into the selected fixative. For preservation of ultrastructure, processing within 24 hours is preferred.
Specimen Transport & Processing Considerations
- Recommended specimen thickness is approximately 1–1.5 mm
- Thicker specimens may not be penetrated rapidly enough to adequately limit autolysis and cellular damage
- Place specimens into PolyTransport Buffer promptly after excision or collection
- After placement in buffer, reduce the specimen temperature to approximately 4°C for transport
- For transport lasting 24–48 hours, maintain specimens at 0–4°C
- Routine paraffin specimens should not remain in PolyTransport Buffer for more than 48 hours
- Electron microscopy specimens should be processed within 24 hours when possible
- No rinsing is required before transfer to light-microscopy or electron-microscopy fixatives
- No rinsing is required before transfer to a rapid-freezing workflow
PolyTransport Buffer is a transport medium rather than a fixative. Fixative selection, fixation time, and subsequent processing should be determined by the intended histologic, immunohistochemical, frozen-section, or electron-microscopy method.
Application Tips
- Place the specimen into PolyTransport Buffer promptly after collection
- Introduce the specimen into buffer at room temperature, then reduce the specimen temperature to approximately 4°C for transport
- Maintain specimens at 0–4°C during extended shipment
- Keep stored specimens at 4°C until fixation or freezing
- Prepare specimens at approximately 1–1.5 mm thickness when practical to facilitate penetration of the transport medium
- Transfer electron microscopy specimens to the selected fixative as soon as practical and preferably within 24 hours
- Transfer routine paraffin specimens to fixative within 48 hours
- No intermediate rinse is required before fixation or rapid freezing
Handling & Storage
- Store PolyTransport Buffer at 20°C
- The buffer is stable for up to one year at room temperature
- Once opened, use within six months
- Do not reuse transport buffer that has already contained a specimen
- Keep transported and stored specimens at the temperatures specified for the intended holding interval
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FAQ
Click a question to expand.
1. What is PolyTransport Buffer used for?
PolyTransport Buffer is a non-fixative medium used to transport excised and biopsy tissue before fixation, rapid freezing, or allocation to histology and microscopy procedures.
2. Is PolyTransport Buffer a fixative?
No. PolyTransport Buffer is a transport medium rather than a fixative. This allows the specimen to be transported before the appropriate fixation or processing method is selected.
3. What is the pH of PolyTransport Buffer?
The specified pH range is 7.2–7.6.
4. How long can tissue remain in PolyTransport Buffer?
Routine paraffin specimens should not remain in the buffer for more than 48 hours. Electron microscopy specimens are preferably processed within 24 hours. Frozen-section, immunohistochemistry, and histochemistry specimens should proceed to fixation or processing within 24–48 hours.
5. At what temperature should specimens be transported?
After the specimen is placed in PolyTransport Buffer, reduce its temperature to approximately 4°C. For transport over 24–48 hours, maintain the specimen at 0–4°C. Stored specimens should remain at 4°C until fixation or freezing.
6. What specimen thickness is recommended?
A specimen thickness of approximately 1–1.5 mm is recommended to permit rapid penetration of the transport medium.
7. Does tissue need to be rinsed after PolyTransport Buffer?
No. An intermediate rinse is not required before transfer to a light-microscopy or electron-microscopy fixative or before rapid freezing.
8. Can PolyTransport Buffer be used before frozen sectioning?
Yes. The formulation contains a cryoprotectant that assists in limiting ice-crystal formation during rapid freezing. Specimens may be transferred directly to a freezing medium such as PolyFreeze Tissue Freezing Medium.
9. Can PolyTransport Buffer be used before immunohistochemistry or histochemistry?
Yes. PolyTransport Buffer may be used for temporary transport before fixation or processing for immunohistochemical and histochemical procedures.
10. Can PolyTransport Buffer be used before electron microscopy fixation?
Yes. It may be used as a temporary transport medium before transfer to the selected electron-microscopy fixative. Processing within 24 hours is preferred for preservation of ultrastructure. Poly/LEM Fixative is one Polysciences fixative for light and electron microscopy.
11. How should PolyTransport Buffer itself be stored?
Store the buffer at 20°C. It is stable for up to one year at room temperature and should be used within six months after opening.
12. Can PolyTransport Buffer be reused?
No. Transport buffer that has already been used for a specimen should not be reused.
13. What sizes are available?
PolyTransport Buffer is available in 250 mL and 500 mL sizes. Catalog number 24311-250 corresponds to the 250 mL format.
Safety & Documentation
Refer to Technical Data Sheet #631 for specimen preparation, transport conditions, holding times, downstream processing, and product-storage guidance. Review the Product Specification for the pH specification and the Safety Data Sheet for current handling and safety information.
