🏠 Home / By Experiment / Molecular Biology /PCR 中文 EN
🧬 Molecular Biology · Core Method

PCR (Polymerase Chain Reaction)

Exponentially amplify a target DNA fragment through denaturation → annealing → extension cycles.
🎯 Difficulty ★☆☆ Beginner ⏱ Total time ~2–3 h 🎯 Use Amplify target DNA fragment
📖 Principle (in one sentence)
Using DNA polymerase guided by primers, target DNA is exponentially amplified (2^n) through repeated cycles of high-temperature denaturation, low-temperature annealing, and optimal-temperature extension.
4 steps below. Click each step to see how-to + linked products. The cart is global — items added on the WB page are merged here too.

📋 Protocol

Full flow at a glance, add products directly
1

Template & Primer Preparation

20 min
Prepare the DNA template (genomic DNA / plasmid / cDNA), design and synthesize forward and reverse primers.
💡 Tip　Keep primer GC content at 40–60%, avoid hairpins and primer dimers.
⚠️ Caution　Too much template inhibits the reaction; 10–100 ng is optimal.
🧪 Materials for this step (click to shop by spec/brand)
PCR 引物（上游 + 下游）Tansoole · Primer SynthesisShop →基因组 DNA 提取试剂盒Tansoole · DNA ExtractionShop →
2

Prepare Reaction Mix

15 min
Assemble the PCR mix on ice: buffer, dNTPs, primers, template, DNA polymerase, and water.
💡 Tip　Prepare a Master Mix first to reduce pipetting error.
⚠️ Caution　Work on ice and add DNA polymerase last to avoid enzyme inactivation.
🧪 Materials for this step (click to shop by spec/brand)
dNTP 混合物Tansoole · PCR ReagentsShop →Taq DNA 聚合酶Tansoole · PCR ReagentsShop →PCR 缓冲液（含 Mg²⁺）Tansoole · PCR ReagentsShop →
3

PCR Amplification (Cycling)

1.5 h
Set program: 95°C denature 30s → 55–65°C anneal 30s → 72°C extend, 30–35 cycles.
💡 Tip　Annealing temperature ≈ primer Tm − 5°C; optimize it first when bands are non-specific.
🧪 Materials for this step (click to shop by spec/brand)
PCR 管（0.2 mL）Tansoole · ConsumablesShop →
4

Gel Electrophoresis Detection

40 min
Run 5 µL product on agarose gel with a DNA ladder, visualize under UV.
💡 Tip　Add loading buffer before loading for settling and visualization.
⚠️ Caution　Nucleic acid stains are toxic; wear gloves and dispose of waste properly.
🧪 Materials for this step (click to shop by spec/brand)
琼脂糖Tansoole · ElectrophoresisShop →DNA MarkerTansoole · DNA LadderShop →核酸染料 / EBTansoole · ElectrophoresisShop →

⚠️ 4 Common Beginner Mistakes (Pitfall Guide)

  • ① Forgot primers or template: missing key components, no amplification.
  • ② Wrong annealing temperature: too high → no product; too low → non-specific bands.
  • ③ Contamination: aerosol contamination causes false positives; work in separate areas and change tips.
  • ④ Too many cycles: 30–35 is enough; more causes non-specific amplification and misincorporation.

❓ FAQ (Troubleshooting)

+No bands — what went wrong?
Check: (1) missing primer/template, (2) enzyme inactive, (3) annealing too high, (4) degraded template.
+Non-specific bands?
Raise annealing temperature, reduce cycles, or optimize primer specificity.
+Faint bands?
Increase template amount, cycle number, or polymerase amount.

🧾 My Shopping List

Items you add on the products page appear here, shared across pages
Nothing added yet
🛒 Go to Products
Data authenticity:Product categories from Tansoole taxonomy; method→step→product connected. Updated: 2026-08-18 · v2.0