Thermo and LDL-responsive acrylated β-cyclodextrin based microspheres enable targeted oleanolic acid release and LDL removal for atherosclerosis therapy

Low-density lipoprotein apheresis (LDL-a) mainly aims to eliminate circulating low-density lipoprotein (LDL) in patients with atherosclerosis, but seldom alleviates the inflammatory responses that drive disease progression. Since the LDL provides more binding sites for acrylated β-cyclodextrin (AβCD) than oleanolic acid (OA), we propose that LDL could displace AβCD-bound OA, enabling LDL-responsive OA release and simultaneous LDL clearance. Herein, a dual-responsive LDL microsphere adsorbent with inflammation-regulating capability is successfully developed. By combining AβCD with the thermo-responsive poly(N-acryloylglycinamide) (PNAGA), the microspheres enable OA release triggered by both elevated LDL concentrations and temperature. The preloaded OA helps reduce nonspecific interactions between the microspheres and other serum proteins, without compromising the intrinsic LDL adsorption capacity of the microspheres. In normal saline, the elevated LDL concentration and temperature both trigger the release of OA from the microspheres, reflecting their dual-responsive behavior. In plasma, the LDL adsorption capacity of the microspheres reaches 76.9 mg/g. Under dynamic whole blood conditions, this value further increases to 184.6 mg/g. To elucidate the underlying mechanism, the isothermal titration calorimetry (ITC) results reveal that the binding constant (Ka) between AβCD and LDL is significantly higher than that between AβCD and OA. Moreover, the lower Gibbs free energy (ΔG) of AβCD-LDL indicates a more stable interaction. The anti-inflammatory potential of the microspheres is verified through co-incubation with RAW 264.7 macrophages, followed by qualitative immunofluorescence staining and quantitative ELISA analysis of inflammatory cytokines. Subsequently, the in vivo LDL clearance efficacy and biosafety of OA/NDSCD microspheres are validated using the rat hyperlipidemic model. This study demonstrates that the dual-responsive microspheres effectively integrate LDL removal and inflammation modulation, offering a promising approach to atherosclerosis. • The microspheres can integrate the LDL removal and inflammation modulation. • The preloaded OA helps reduce nonspecific interactions between the microspheres and other serum proteins. • LDL-responsive OA release mechanism is validated by ITC based on binding differences. • Simultaneous LDL clearance and OA release based on differences in binding of LDL and OA to microspheres. • Thermo-responsiveness enhanced both LDL scavenging and OA release.