Abstract
Lesion positioning therapy optimizes medical treatment by directly targeting lesions. However, strong physical barriers greatly hinder its wide use. Here, the Chinese acupuncture needles (CA-needles) with a screw-thread structure at the tip (ST-needle) and the hydrogel with the function of adhesive metal and loaded drug sustained-release structure are designed, through the minimally invasive and precise positioning of lesions by ST-needles, the dry-wet conversion of hydrogel with absorbing fluids and swelling, and the rotation back of ST-needles, the hydrogel is precisely positioned in the subchondral bone with physical barrier to achieve precise positioning therapy for lesions. In vitro experiments show that the ST-needle penetrates the physical barrier of cartilage and enters the subchondral bone. Simultaneously, the hydrogel transfer efficiency of the ST-needle (73.25%) is significantly higher than that of the CA-needle (29.92%) due to the protective effect of the screw-thread structure. In vivo experiments demonstrate that precise positioning in subchondral bone in osteoarthritis rats with ST-needles effectively inhibits abnormal subchondral bone remodeling, alleviating the degeneration and degradation of cartilage. Therefore, ST-needles achieve lesion positioning therapy through minimally invasive penetration of physical barriers, precisely positioning within lesions, and delivering hydrogel to release drugs.