Application of Biological Buffer CAPS 1135-40-6 in PCR Diagnostic Kit

The chemical properties of CAPS: the "golden equilibrium point" for weak base buffering

CAPS is a zwitterionic buffer with a pKa value of 10.4 (25 ℃), exhibiting excellent buffering ability in alkaline environments. Compared with traditional buffering agents such as Tris or HEPES, the buffering range of CAPS (pH 9.7-11.0) is more in line with the requirements of certain special systems in PCR reactions. The cyclohexylamine group in the molecular structure of CAPS buffer endows it with good hydrophobicity, while the sulfonic acid group ensures water solubility. This "flexible and rigid" characteristic allows CAPS to maintain solution pH stability while reducing non-specific interference with enzyme activity, providing a mild and stable environment for PCR reactions.

CAPS powder

The core role of CAPS in PCR

1. PH stability ensures enzyme activity: CAPS precisely regulates the pH value of the reaction system to avoid pH drift caused by solution evaporation or chemical degradation during high-temperature denaturation steps, ensuring that the enzyme catalyzes DNA synthesis under optimal conditions and significantly improves amplification efficiency.

2. Inhibiting non-specific binding and enhancing specificity: CAPS maintains stable ion strength, reduces the probability of primer template mismatch, and its unique chemical structure can reduce solution surface tension, optimize droplet formation, and further reduce background noise in high-precision detection such as PCR.

3. Compatible with complex samples and enhanced anti-interference ability: Clinical samples (such as blood and saliva) often contain inhibitors that may interfere with PCR reactions. The buffer system of CAPS can neutralize the charge effect of some inhibitors, combined with its alkaline environment's denaturation effect on certain protein inhibitors, significantly improving the adaptability of the kit to complex samples.

Practical application cases of CAPS: extensive validation from laboratory to clinical settings

In the nucleic acid detection of COVID-19, CAPS has been included in the PCR kit formula by several authoritative organizations. For example, a certain brand's reagent kit using CAPS buffer system showed higher sensitivity in comparative testing and was able to maintain pH stability under high temperature conditions, reducing false negative results. In addition, in scenarios such as genetic disease mutation detection and tumor marker analysis, the weak alkaline environment of CAPS can optimize probe binding efficiency, enhance fluorescence signal intensity, and provide support for the detection of low abundance targets.

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