Introduction

With the continuous growth of the global in vitro diagnostics (IVD) market, China, as one of the world’s largest independent healthcare consumption markets, is entering a period of rapid development.

The localization of core raw materials is not only a key focus of national policy but also the cornerstone for every IVD company to build its core competitiveness.

Although some low- to mid-end raw materials have achieved domestic self-sufficiency, high-end core materials such as enzymes, antibodies, and labeling reagents are still heavily dependent on imports. Among these, the field of labeling reagents has proven particularly challenging due to the complexity of conjugation technologies, strict batch-to-batch variation control, and large-scale manufacturing difficulties.

Core Labeling Reagent SA-HRP: The “Master Key” in IVD

Among numerous critical labeling reagents, streptavidin-horseradish peroxidase conjugate (SA-HRP) plays the role of a “master key” due to its high efficiency and specificity.

As a crucial signal amplification system, SA-HRP significantly enhances detection sensitivity and is widely used in enzyme-linked immunosorbent assays (ELISA), Western blot (WB), flow cytometry (FC), immunohistochemistry (IHC), in situ hybridization (ISH), and protein microarrays, among other immunoassay platforms.

In essence, the performance of SA-HRP directly determines the accuracy and reliability of these mainstream detection methods.

Industry Pain Points: The “Painful Dependence” on Imported SA-HRP

The supply of SA-HRP has long relied on imports, with key materials facing potential supply chain disruptions, unstable prices, and rising cost pressures. Meanwhile, several performance-related issues remain unsolved:

1. Large batch-to-batch variation: 

Performance fluctuations between different batches of imported products force companies to revalidate and adjust their production processes with every batch, extending production cycles and increasing quality control costs.

2. High non-specific adsorption: 

This leads to elevated background signals, increasing the risk of false positives and compromising test accuracy.

3. Stability challenges: 

Product activity may decline during transportation, storage, or use, indirectly shortening the shelf life of diagnostic kits.

These pain points have become bottlenecks restricting both industry innovation and enterprise development.

Hzymes Biotech: Crafting a “Blade of Excellence” in Domestic SA-HRP Through Innovative Processes

Facing these challenges, Hzymes Biotech adheres to its core values of Customer First, Innovation, Excellence, Responsibility, and Win-Win Cooperation, channeling strong R&D capabilities to overcome key technical hurdles.

1. Genetic Engineering Optimization of High-Quality Raw Materials

The company uses a recombinant core SA (molecular weight: 53.2 kDa) engineered to remove non-functional sequences while retaining only the active core domain. This recombinant SA exhibits superior stability and solubility compared to the natural form and exists as a homotetramer, with each mole capable of binding four moles of biotin.

The horseradish peroxidase (HRP) component, produced through recombinant expression, offers high purity and strong enzymatic activity.

2. Precision-Controlled Conjugation Technology

HRP contains abundant carbohydrate groups, which, upon oxidation by sodium periodate, form aldehyde groups that react with amino groups on streptavidin (SA) to produce Schiff bases. Excess sodium periodate is neutralized with ethylene glycol, and unreacted aldehydes are reduced using sodium borohydride to form stable amide bonds. HRP is used in excess, and the final conjugate is purified via molecular sieving to remove free HRP.

The reaction principle diagram of HRP-labeled SA

By integrating recombinant technology with precise process control, Hzymes efficiently and stably combines high-activity recombinant SA with recombinant HRP, resulting in a domestically produced SA-HRP product characterized by minimal batch variation, ultra-low non-specific adsorption, and exceptional stability — ensuring a secure and consistent supply.

Product Advantages: The “Outstanding Performance” of SA-HRP

1. Minimal batch-to-batch variation: 

Controlled within ±10% across three batches.

In gradient dilution ELISA tests using biotinylated antibodies coated on 96-well plates, three SA-HRP batches demonstrated OD value variation of less than ±10% at 405 nm after TMB color development for 20 minutes.

2. Ultra-low non-specific adsorption: 

Clean background signal.

Four self-developed SA-HRP lots diluted to 0.0625 μg/mL were compared with imported controls, showing strong reactivity and exceptionally low background noise.

3. Excellent stability: 

Over 90% signal retention after 7 days at 37°C.

Gradient-diluted SA-HRP samples were stored at 2–8°C and 37°C (for 1, 4, and 7 days). ELISA results showed more than 90% signal retention after 7 days at 37°C.

Validation: Performance on Par with Imported Reagents

Three concentration gradients of self-developed SA-HRP were compared with imported products. Results showed that the reaction signal of the Hzymes product increased proportionally with concentration, maintaining a clean background.

When tested on eight clinical samples alongside imported controls, the results were fully consistent — demonstrating that Hzymes’ SA-HRP performs equivalently to imported reagents.

Product Information