Intelligent stealth andrographolide imprinted drug carrier of poly(2-ethyl-2-oxazoline) with multi-stimuli responsiveness and A549 lung cancer cell cytotoxicity†

The stealth segment poly(2-ethyl-2-oxazoline) (PEOX) was attempted to be grafted onto the surface of an andrographolide-imprinted polymer (ADR-MMIP) invented in our laboratory to obtain a new intelligent stimuli-responsive drug carrier with better controllable ADR release, anti-cancer, and stealth (ability to evade the immune system) properties. Serial characterization using modern instrumental analysis techniques, including Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), transmission electron microscopy (TEM) as well as Brunauer–Emmett–Teller (BET) and zeta potential (ZP) analyses, confirmed that the novel target ADR/PEOX-MMIP was successfully prepared. Material performance tests showed that ADR/PEOX-MMIP had favourable stability and exhibited a mere decrease of 14.83% in adsorption capacity after five adsorption–desorption cycles, good selectivity adsorption for ADR with a relative selectivity coefficient of 1.4375, an acceptable ADR loading capacity of 11.46 mg g⁻¹, and satisfactory ADR-controllable release with a maximum cumulative drug release rate of 73.10% in response to pH/redox/light stimulation in vitro and a slower release time of 210 h compared with ADR-MMIP (60 h). Notably, ADR/PEOX-MMIP possessed definite A549 lung cancer cell cytotoxicity, with a maximum cell inhibition rate of 36% at a concentration of 160 μg mL⁻¹ and excellent stealth performance for escaping the non-specific effects of macrophages, which indicate that it should be able to effectively improve the present therapeutic defects of ADR, both in theory and real-world practice, and provide a new idea for the development of intelligent drug carriers in the future. The adsorption mechanism of the prepared target material is also discussed in detail in this study.