Table 1.

Summary of the various considered combination product formulations used for the in vitro and in vivo characterization experiments. The HA raw materials were obtained from the same source for each group (i.e., 2.2–2.4 MDa MW ¹), and each formulation was submitted to the same sterilization cycle before direct use or incorporation of the lyophilized FE002 cells. Therefore, all characterization experiments were performed using steam-sterilized hydrogels. HA, hyaluronic acid; MW, molecular weight; PNIPAM, poly(N-isopropylacrylamide).

Formulation Type	Gross (Co-)Polymer Concentration (mg/mL)	Net HA Concentration (mg/mL) 2	Lyophilized FE002 Chondroprogenitor Presence (Y/N)
HA	10	10	N
HA-L-PNIPAM	37	10	N
HA + Cells	10	10	Y (3 × 106 cells/vial)
HA-L-PNIPAM + Cells	37	10	Y (3 × 106 cells/vial)

¹ The retained HA raw material specifications (i.e., molecular weight class) were selected based on technical imperatives (i.e., need of easy injection, maximization of post-sterilization rheological properties) and with focus on clinical/functional aspects (i.e., maximization of in situ product viscosity and residence time, for enhanced function). ² The net HA contents for the HA-L-PNIPAM co-polymers were calculated according to the degrees of substitution experimentally obtained in ¹H NMR spectroscopy characterization.