ABSTRACT Magnetosome chains biosynthesized by magnetotactic bacteria combine high magnetic responsivity with efficient magnetothermal conversion but face limitations due to fragile assembly and potential biosafety risks. Here, we report a biomimetic Stöber‐based encapsulation strategy that preserves the native chain architecture while imparting structural robustness and enhanced safety. The resulting B‐MNC exhibit a coercivity (33.6 mT), approximately 5× higher than magnetosomes, 1.4× higher than intact magnetotactic bacteria, and 2.2× higher than chemically synthesized analogs (C‐MNC22). Magnetic characterization reveals ideally uniaxial single‐domain behavior with a remanence ratio ( M rs /M s ) of 0.5, outperforming magnetosomes (0.35), bacteria (0.46), and C‐MNC22 (0.27). Under an alternating magnetic field (144.1 kHz, 34.7 kA m −1 ), aligned B‐MNC achieve a specific absorption rate ( SAR ) of 1749.7 W g −1 , which is approximately 4.72× greater than purified magnetosomes, enabling rapid and efficient heating. In vitro, silica encapsulation markedly improves colloidal stability and cytocompatibility. Upon magnetic hyperthermia (42°C, 20 min), B‐MNC induce 71.4% death of MB49 bladder cancer cells versus only 12.4% for bare magnetosomes. This biomimetic assembly preserves the superior magnetic properties of native magnetosome chains while enhancing magnetic hyperthermia efficacy and biostability, establishing B‐MNC as a promising platform for safe and effective magnetic cancer therapy.
Gao et al. (2026) studied this question.