I want to buy an expression profiling gene chip. Which is more suitable for mouse tissues, Agilent or Affymetrix?

Hybridization ovens and scanners are not mandatory purchases. Many university platforms or third-party companies offer surrogate hybridization and scanning services for Agilent or Affymetrix, charged per slide, suitable for projects with 20 slides or fewer. The key is to confirm that the third party uses a scanner model compatible with the chip, for example, Agilent chips with SureScan or the same series, and Affymetrix with the GeneChip Scanner, and to require output of raw data formats such as .tif, .CEL, or Feature Extraction results. It is best to first test with 1 standard quality control chip or a slide with normal signal from a previous batch to confirm that the PMT settings and resolution of their scanning are consistent with the manufacturer's protocol. If the budget is tight, you can purchase only the chips and outsource hybridization, washing, and scanning as a whole, but the contract should specify data quality standards and compensation for delays.

From a reproducibility perspective, Affymetrix's closed-tube single-channel system is more beginner-friendly and offers better batch-to-batch stability; Agilent's 60-mer probes also provide good specificity and dynamic range, but dye bias must be noted when switching samples in two-color experiments. For 20 samples, it is recommended not to run a single slide as a single group; use at least 3-4 biological replicates per group, and reserve 1-2 technical replicates. Before selecting a platform, you can download mouse liver Affy and Agilent datasets from GEO, run a quick PCA with limma, and examine batch effects and background distribution. If samples are to be submitted across different times, it is advisable to use the same batch of extraction kits and to randomize sample processing and submission order to reduce non-platform-related interference.

For 20 mouse liver tissue samples, if the budget is tight, it is advisable to first clarify whether single-channel or dual-channel requirements are needed. Agilent's SurePrint chips offer flexible spotting, with rapid probe design updates, and generally have shorter lead times than Affymetrix's standard chips; Affymetrix has accumulated more historical data in public databases, with a relatively stable reputation for reproducibility. For both companies on the same platform, intra-batch CV can typically be controlled to around ten-plus percent, but Agilent dual-color experiments are more operator-dependent. You can request reference data for mouse liver from both companies' agents separately, then use your own RNA for 1-2 pilot experiments to check the number of detected genes and internal control consistency. When considering price, do not look only at the chip unit price; calculate the total cost including hybridization, scanning, and QC.