PCL implants were processed for scRNAseq by pooling 2-3 mice for each condition at each time point. Briefly, scaffolds were minced and incubated in RPMI containing 0.2 U/mL Liberase TL (Roche) at 37 ℃ for 20 minutes and then passed through a 70 µm filter to make a single cell suspension. ACK buffer (Gibco) was used to lyse RBCs in suspension, and cells were washed in PBS before being resuspended to 1 million cells/mL in PBS containing 0.04% w/v BSA 10x Genomics single cell 5' kit