As a leading global upstream enterprise in the in vitro diagnostics platform, DIA-UP has been deeply engaged in core biological raw materials for reagents for more than a decade and is a professional provider of special protein raw materials. The self-developed high-quality raw materials have undergone repeated testing and multi-platform verification, and a more systematic and rigorous process and management system are adopted for effective quality control. The first-generation intrinsic factor protein independently developed by DIA-UP has been widely praised by domestic and foreign customers since its launch. Through the continuous exploration and iterative optimization of the core technical team, a brand-new generation of intrinsic factor protein has been newly launched, which can be flexibly applied to multiple platforms such as fluorescent chromatography and chemiluminescence. After multiple steps of column chromatography, 1mol of intrinsic factor can bind to >0.95mol of VB12, with higher sensitivity, higher binding capacity, and better reagent performance. At the same time, Deaoping has established a safer and more stable supply chain, with stable delivery time and rapid response, which can minimize the time cost of customers and efficiently promote the stable development of experimental work.

In the development of high-difficulty luminescent reagents for VB12, the commonly used pairing is a combination of intrinsic factor protein (IF) and VB12 hapten. However, experimental procedures have shown that when intrinsic factor protein (IF) is coated onto magnetic beads, the binding capacity of the intrinsically active IF to VB12 in samples decreases. The cause of this phenomenon is that the covalent coupling of IF to magnetic beads induces structural changes in IF, which significantly affects its affinity for VB12 in samples.

In response to this issue, the core technical team of DIA-UP has independently developed an intrinsic factor magnetic bead coating tool - the intrinsic factor bridging antibody. It achieves indirect coupling between the intrinsic factor protein (IF) and magnetic beads. On the one hand, it can efficiently avoid structural changes caused by covalent coupling between IF and magnetic beads, completely preserving the high binding activity of IF to VB12. On the other hand, it can significantly reduce the dosage of intrinsic factor, helping customers effectively reduce the development cost of VB12 reagents and facilitating the production optimization of high-difficulty reagents.

· Performance Verification Report - Chemiluminescence Platform

When the IF bridging antibody is coated on magnetic beads and different concentrations of intrinsic factor protein (IF): 0-0.5-5-50 ng/mL are added, it shows a good dose-response, proving that it can effectively bridge the IF protein.

· To further confirm whether the binding site of the IF bridging antibody to the intrinsic factor protein would interfere with the binding of VB12, the following experimental protocol was designed:

Generally, the intrinsic factor (IF)-ALP conjugates prepared based on SMCC/SATA and other schemes have heterogeneity, 

and may damage the VB12 binding site on the intrinsic factor. The connection site of intrinsic factor IF-ALP (SDC) is far away

from the VB12 binding domain.

When DIA-UP's intrinsic factor IF-ALP is used to replace the corresponding component of commercial VB12-AP reagents, 

it shows a better signal-to-noise ratio and sensitivity, and the usage concentration of the conjugate is only 5 ng/mL.

Meanwhile, the thermal accelerated stability of DIA-UP's intrinsic factor IF-ALP was further evaluated. 

When stored at 37°C for 7 days at a concentration of 5 ng/mL, the activity retention rate exceeded 90%.