Beware of Shear Force

What Is Really Damaging Your Samples During Centrifugation?

做离心实验时，你有没有遇到过这种情况：明明离心参数没问题，样品却出现降解、失活——细胞破裂、蛋白变性、病毒失活……其实，这很可能不是离心力的问题，而是被你忽略的"隐形杀手"：剪切力。

Have you ever encountered this problem in centrifugation experiments: the parameters seem correct, but the sample still shows degradation or inactivation — cell rupture, protein denaturation, viral inactivation? The culprit may not be centrifugal force, but the often-overlooked "invisible killer": Shear Force.

很多人只关注离心力够不够强，却不知道剪切力会直接破坏样品活性。今天就拆解剪切力的核心理论，告诉你它是什么、从哪来，以及哪些情况会让它变强。

Many people focus only on whether the centrifugal force is strong enough, unaware that shear force can directly destroy sample integrity. In this article, we'll break down the core theory of shear force — what it is, where it comes from, and what makes it stronger.

Section 1: What Is Shear Force — The Invisible Sample Destroyer

剪切力，简单来说，是流体在离心场中运动时，因"速度差异"产生的内摩擦力。我们可以把它理解为：离心时，样品液体内部的"分子/颗粒"互相"拉扯、摩擦"，或者液体与转子壁、离心管壁发生"撞击、摩擦"，产生的一种"破坏性力量"。

In simple terms, shear force is the internal friction generated by velocity differences within a fluid moving in a centrifugal field. Think of it this way: during centrifugation, molecules and particles within the sample liquid "pull and rub" against each other, or the liquid "impacts and rubs" against rotor walls and tube walls — producing a destructive mechanical force.

Section 2: Three Main Sources of Shear Force

剪切力不是凭空产生的，主要与离心机结构、操作参数、流体状态有关，具体有3个核心来源：

Shear force does not appear out of nowhere — it is primarily linked to centrifuge structure, operating parameters, and fluid dynamics. There are three core sources:

① 流体速度梯度与湍流  | Fluid Velocity Gradient and Turbulence

离心时，样品液体随转子旋转，靠近转子壁的液体速度快，中心的速度慢，这种"速度差"会产生剪切力；如果转速过快、液体晃动，还会形成湍流，进一步放大剪切力。

During centrifugation, the sample liquid rotates with the rotor. Fluid near the rotor wall moves faster than fluid at the center — this velocity gradient generates shear force. If rotation speed is excessive or liquid swirls, turbulence develops and further amplifies shear force.

② 壁面冲击与摩擦  | Wall Impact and Friction

样品液体在离心过程中，会撞击离心管壁、转子内壁，或在流道中流动时与壁面摩擦，产生局部强剪切力。尤其是角转子和垂直转子，这种冲击更明显。

Sample liquid impacts the centrifuge tube walls and rotor inner walls during centrifugation, and friction occurs as liquid flows through channels — generating localized high shear forces. Angle rotors and vertical rotors are particularly prone to this effect.

③ 加速/减速的冲击 | Acceleration/Deceleration Impact

离心机启动时快速加速、停止时快速减速，样品液体会因惯性产生"冲击性流动"，瞬间产生较大剪切力。这也是很多敏感样品被破坏的主要原因。

When the centrifuge starts with rapid acceleration or stops with abrupt braking, the sample liquid undergoes "impulse flow" due to inertia — instantly generating strong shear forces. This is one of the leading causes of damage to sensitive samples.

Section 3: Shear Force Differences by Machine Type and Rotor

剪切力的大小，和离心机类型、转子设计直接相关，这也是我们选择"低剪切机型"的核心依据：

The magnitude of shear force is directly related to the centrifuge type and rotor design — this is the core basis for selecting "low shear" equipment:

不同转子的剪切力比较| Shear Force Comparison by Rotor Type

Section 4: The Hidden Hazards of Shear Force

Summary

剪切力是离心实验中最容易被忽略的破坏因素。来源主要有三：速度梯度/湍流、壁面冲击、加减速冲击。选择低剪切转子（水平转子优先）、慢加减速，是保护敏感样品的关键。下一篇，我们来讲如何在保证离心力的前提下，有效降低剪切力的实操技巧！

Shear force is the most overlooked damaging factor in centrifugation. Its three main sources are: velocity gradients/turbulence, wall impact, and acceleration/deceleration impulses. Choosing low-shear rotors (swing-out preferred) and slow speed ramps are key to protecting sensitive samples. Next, we'll cover practical techniques to reduce shear force while maintaining sufficient centrifugal force!

点赞收藏，下一篇解锁"降剪增离"的实操技巧，实验少走弯路！

BIO-CHEM T5R 低速冷冻离心机

T5R 低速冷冻离心机  |  T5R Low-Speed Refrigerated Centrifuge

产品简介| Product Overview

T5R型低速冷冻离心机是一款台式离心机，具备低速多功能性和低温恒温制冷能力，适用于中高通量实验。广泛适用于生物研究、临床检测以及真空采血管去帽等专业应用，能够满足对大容量样本进行分离和纯化的需求。

The T5R is a benchtop low-speed refrigerated centrifuge combining multi-functional low-speed capability with precise low-temperature refrigeration, suitable for medium-to-high throughput experiments. It is widely used in biological research, clinical diagnostics, and specialized applications such as vacuum blood tube decapping, meeting the demands of large-volume sample separation and purification.

T5R 开盖展示  |  T5R — Open Lid View

核心特点| Key Features

① 7寸彩色高灵敏触控电阻屏，可戴手套操作，人性化界面，操作简单便捷。

7-inch color high-sensitivity resistive touch screen with glove-operable design; intuitive user interface for convenient operation.

② 单片机控制，无刷电机驱动，运行稳定、噪音低、转速精度高（±10r/min），无碳粉污染。

MCU-controlled brushless motor drive ensures stable operation, low noise, high speed accuracy (±10 r/min), and no carbon dust contamination.

③ 结构自锁与电机自锁双重锁紧，具有门锁安全检测及门盖未关闭界面提醒。

Dual-lock mechanism (structural + motorized) with door sensor detection and on-screen cover-open alert.

④ 进口泰康压缩机，无氟制冷剂，上电后门盖关闭可持续制冷，确保温度恒定。

Imported Tecumseh compressor with eco-friendly CFC-free refrigerant; continuous refrigeration once powered on with lid closed, maintaining stable temperature.

⑤ 快速预制冷，从室温（24℃）预冷至4℃仅需5–7分钟，极大节省实验等待时间。

Rapid pre-cooling from room temperature (24°C) to 4°C in just 5–7 minutes, greatly reducing experiment waiting time.

⑥ 电机防冷凝水专利设计，防止长时间开机产生冷凝水锈蚀轴承，延长使用寿命。

Patent-pending anti-condensation motor design prevents condensate from corroding bearings during extended use, extending service life.

⑦ 离心结束后可设置门锁自动开启，减少操作步骤，方便取放样品。

Programmable auto-unlock after run completion; reduces procedural steps and simplifies sample handling.

⑧ 内腔与样品挥发物接触部位全采用304不锈钢材质，防腐耐用。

All internal surfaces in contact with sample vapors made of 304 stainless steel for corrosion resistance and durability.

⑨ 实时转速与离心力切换，可直接设置离心力运行，故障时有声音和指示灯提示。

Real-time RPM/RCF switching with direct RCF input; audio and LED fault alerts.

⑩ 升降速快慢可调（9档），防止样品混悬，可设置梯度离心，保证离心效果。

9-level adjustable acceleration/deceleration to prevent sample resuspension; supports programmable gradient centrifugation for optimal results.

产品参数| Technical Specifications

T5R 转子配置  |  T5R Rotor Configuration