固定的目的在于保存细胞和组织的原有形态结构，固定剂能阻止内源性溶酶体酶对自身组织和细胞的自溶、抑制细菌和霉菌的生长，固定剂通过凝固、生成添加化合物等使蛋白质内部结构发生改变，从而使酶失活，固定剂对细胞核细胞外成分发生物理改变，固定液主要分为醛类固定液、汞类固定液、醇类固定液、氧化剂类固定液、苦味酸盐类固定液等，较为常用的是醛类中的福尔马林、醇类中的乙醇。
Davidson's 固定液又称戴维森固定液或 Hartmann's 固定液，主要由 15% 乙醇、5% 乙酸、甲醛、去离子水等组成，不含染料、汞或其他金属，是一种快速固定液，有良好的保存细胞核特点，并且产生的福尔马林色素最少，而且产生的收缩率更低，整体形态学细节也更好，可用于常规组织病理学检查，特别适用于肿瘤、骨髓、妇科样本、多脂肪的乳腺和组织活检，也可用于睾丸活检和含脂肪淋巴结的过夜固定。此外，Davidson's 固定液是全眼固定的首选固定液，可提供最佳的组织保存条件，同时避免视网膜脱离。常用于快速脱水和固定以及冷冻切片的快速固定，可作为组织材料的保存剂。该试剂仅用于科研领域，不适用于临床诊断或其他用途。
操作步骤 (仅供参考):
1、取新鲜组织放入 Davidson固定液, 置于室温固定 1-2 天，小样本固定时间不超过 24 小时。对于后续做免疫组化实验的组织固定标本不超过 24 小时，常规组织病理学实验的组织固定不超过 48 小时。
2、从 Davidson固定液中取出组织标本，并用自来水短暂冲洗。
3、固定结束后，可将样本放入 10% 福尔马林或 70% 乙醇中保存。
注意事项:
1、本固定液含一定量的甲醛，对人体有一定损害，请在通风好的环境下小心操作，避免吸入。
2、组织取材的厚度不同，固定时间也不同，对组织恰当的选材有利于固定液的渗透；常规活检组织比较适合的厚度为 2~4mm, 一般不超过 6mm。
3、固定液的容量应足够，一般固定液与组织块的体积比率应大于 10:1; 如果容积不够大，可以在固定期间更换 1~3 次固定液。
4、温度对固定的影响很明显，提高温度可以加速固定作用，但温度不宜过高。
5、取出新鲜组织后，应及时固定。
6、如果标本特别坚硬 (如眼), 固定后可在 70% 乙醇中保存 1 天，再转移到 90% 乙醇中保存 1 天，最后在无水乙醇中保存 1 天，以使标本更容易切割。
7、为了您的安全和健康，固定应在通风橱进行，穿实验服并戴一次性手套操作。
8、试剂开封后请尽快使用，以防影响后续实验效果。
The purpose of fixation is to preserve the original morphological structure of cells and tissues. Fixatives prevent autolysis of tissues and cells triggered by endogenous lysosomal enzymes and suppress the growth of bacteria and fungi. Through coagulation and adduct formation, fixatives alter the internal structure of proteins to inactivate enzymes and induce physical changes to cell nuclei and extracellular components. Fixatives are mainly classified into aldehyde, mercury, alcohol, oxidant and picrate categories, among which formalin (aldehyde type) and ethanol (alcohol type) are widely adopted.
Davidson's Fixative, also named Hartmann's Fixative, is composed of 15% ethanol, 5% acetic acid, formaldehyde and deionized water. It contains no dyes, mercury or other heavy metals. As a rapid fixative, it delivers excellent nuclear preservation, generates minimal formalin pigment, causes low tissue shrinkage and retains superior morphological details. It is applicable to routine histopathological examinations, especially for tumors, bone marrow, gynecological specimens, fatty breast tissues and biopsies. It can also be used for overnight fixation of testicular biopsies and fatty lymph nodes. Moreover, Davidson's Fixative is the preferred fixative for whole-eye specimens, providing optimal tissue preservation and preventing retinal detachment. It is widely used for rapid dehydration, routine fixation and fast fixation for frozen sections, and can serve as a preservative for tissue samples. This reagent is for research use only and not intended for clinical diagnosis.
Operating Procedures (For Reference Only)
1.Immerse fresh tissues in Davidson's Fixative and fix at room temperature for 1–2 days. Fixation of small samples shall not exceed 24 hours. For specimens intended for subsequent immunohistochemistry, fixation time shall be within 24 hours; for routine histopathological tests, fixation shall not exceed 48 hours.
2.Take tissue specimens out of Davidson's Fixative and rinse briefly with tap water.
3.After fixation, store samples in 10% formalin or 70% ethanol.
Precautions
1.This fixative contains formaldehyde which is harmful to human health. Operate cautiously in a well-ventilated area and avoid inhalation of vapors.
2.Fixation time varies with tissue thickness. Proper trimming facilitates penetration of fixative. The optimal thickness of routine biopsy tissues is 2–4 mm and shall not exceed 6 mm.
3.Use sufficient volume of fixative; the volume ratio of fixative to tissue block shall be greater than 10:1. Replace the fixative 1–3 times during fixation if the volume is insufficient.
4.Temperature has a remarkable impact on fixation. Higher temperature accelerates fixation, yet excessive temperature must be avoided.
5.Fix fresh tissues immediately after dissection.
6.For hard specimens such as eyeballs, store in 70% ethanol for 1 day after fixation, then transfer to 90% ethanol for another day, followed by absolute ethanol for 1 day to improve sectioning performance.
7.All fixation operations must be carried out in a fume hood with lab coat and disposable gloves worn for personal safety.
8.Use the reagent promptly after opening to avoid compromised experimental results.
ZJ26F0939292
危险品化学品经营许可证（带存储）