Domestic substitution for imported exosome extraction reagents, seeking price comparison and trial samples.

For domestic substitution, I suggest not ordering the large box yet. Contact the manufacturer to request a trial sample, run one batch each with 10 mL of cell supernatant and serum, and compare it side by side with the SBI or Invitrogen product you are currently using. Focus on three key indicators: particle count, CD63/TSG101 band intensity, and Calnexin negativity. When calculating the cost per run, include the processing volume and the consumables required for additional precipitation solution or columns, rather than only comparing the box price. If a box costing 500-800 yuan can only be used for 5-6 runs, it is actually not cheap.

The yield of domestic precipitation methods is not necessarily lower than that of SBI, but the background of serum samples tends to be high; if NTA or mass spectrometry is to be performed subsequently, prioritize trying domestic kits based on membrane affinity or size exclusion, as their particle size distribution is closer to that of the Invitrogen column method. Cell supernatant is relatively clean, allowing for higher tolerance of purity. It is recommended to use domestic precipitation methods for cell supernatant to reduce costs, and use membrane affinity or SEC for serum to ensure purity. Validate the two sample types separately; do not use a single kit for both. This way, both funding and results will be secure.

Batch-to-batch stability must be asked about in advance. Require the manufacturer to provide QC data for at least two batches, such as the main peak range of particle size, total protein amount, and particle count. After arrival, perform your own inter-batch validation: divide the same serum sample into 3 tubes, extract using different batches, run Western to compare CD63, and use NTA to check the deviation in main peak particle size. If the supplier cannot specify inter-batch quality control standards, it is advisable to be cautious. Within one week of supply, domestic manufacturers in Jiangsu, Zhejiang, and Shanghai are generally able to deliver, and many support SF Express next-day delivery.

Same here. Imports are too expensive. I've tried a domestic brand before; the purity was acceptable, but you have to optimize it yourself.

For domestic reagents, be sure to get trial samples first and run NTA and WB comparisons before buying in bulk.