Transforming small-molecule antibiotics into carrier-free nanoantibiotics represents an opportunity for developing new multifunctional therapeutic agents. In this study, we demonstrate that acoustic cavitation produced by high-frequency ultrasound transforms the antibiotic doxycycline into carrier-free nanobiotics. Upon sonication for 1 h at 10–15 W cm⁻³, doxycycline molecules underwent hydroxylation and dimerization processes to ultimately self-assemble into nanoparticles of ∼100–200 nm in size. Micrometer sized particles can be also obtained by increasing the acoustic power to 20 W cm⁻³. The nanodrugs exhibited antioxidant properties, along with antimicrobial activity against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacterial strains. Our results highlight the feasibility of the ultrasound-based approach for engineering drug molecules into a nanosized formulation with controlled and multiple bio-functionalities.

将小分子抗生素转化为无载体纳米抗生素代表了开发新的多功能治疗剂的机会。在这项研究中，我们证明了高频超声产生的声空化将抗生素多西环素转化为无载体的纳米生物。在 10-15 W cm ^-3下超声处理 1 小时后，强力霉素分子经历羟基化和二聚化过程，最终自组装成尺寸约为 100-200 nm 的纳米颗粒。还可以通过将声功率增加到20 W cm ^-3来获得微米尺寸的颗粒。纳米药物表现出抗氧化特性，以及对革兰氏阳性（金黄色葡萄球菌）和革兰氏阴性（大肠杆菌）的抗菌活性菌株。我们的结果突出了基于超声的方法将药物分子工程化为具有可控和多种生物功能的纳米级制剂的可行性。