Related Experiment Videos
Formalin removal from archival tissue by critical point drying
Sheng-Guo Fang1, Qiu-Hong Wan, Noboru Fujihara
1sgfang@mail.hz.zj.cn
Biotechniques
|September 20, 2002
Summary
High molecular weight DNA can be extracted from old fixed tissues using gradual dehydration and critical point drying. This method yields reliable DNA suitable for various analyses, including PCR amplification and fingerprinting.
Area of Science:
- Biochemistry
- Molecular Biology
- Histology
Background:
- Formalin fixation causes DNA cross-linking, complicating nucleic acid extraction from tissues.
- Older fixed tissue specimens yield fragmented DNA, limiting its use to PCR amplification.
Purpose of the Study:
- To develop a method for extracting high molecular weight DNA from old formalin-fixed tissue specimens.
- To assess the reliability and utility of DNA extracted using the novel method.
Main Methods:
- Gradual dehydration and critical point drying were employed for DNA extraction.
- DNA quality was assessed by its ability to serve as a template for amplifying mitochondrial DNA (mtDNA) and nuclear DNA (nDNA) fragments.
- Fingerprinting analysis was performed to evaluate DNA hybridization capabilities.
Main Results:
- High molecular weight DNA (>194 kb) was successfully extracted from fixed tissue samples aged 16-70 years.
- The extracted DNA was reliable for amplifying mtDNA fragments (403 and 1198 bp) and an nDNA fragment (1844 bp).
- DNA derived by this method demonstrated successful hybridization with DNA probes.
Conclusions:
- Gradual dehydration and critical point drying enable the extraction of high-quality, high molecular weight DNA from old formalin-fixed tissues.
- This method significantly expands the utility of archival fixed tissue specimens for molecular analyses.
- Extracted DNA is suitable for amplification, restriction digestion, and hybridization studies.