In Situ Construction of Upconverting Nano-Bacteria Biohybrids via Biomimetic Mineralization for Synergistic Antitumor Phototherapy

Nano-bacteria biohybrids, which combine the advantages of nanomaterials and bacterial cells, have emerged as innovative platforms for cancer treatment. Integrated with optical nanomaterials, these biohybrids enable effective phototherapy. To overcome the challenge of limited tissue penetration by visible light in phototherapy, upconversion nanoparticles can be used to convert near-infrared (NIR) light into visible light, enabling the treatment of deep-seated tumors. In this study, we present a rapid method to fabricate upconversion nanoparticle-bacteria biohybrids (<i>E. coli</i>@BiF₃:Yb/Er) via biomimetic mineralization under biocompatible conditions within minutes. Additionally, palladium nanoparticles are co-mineralized, enabling the biohybrids to perform both photodynamic and photothermal therapies under NIR light. When applied to mouse models of melanoma and cervical cancer, these biohybrids target the tumor sites efficiently without causing systemic toxicity. Upon excitation with 980 and 808 nm NIR light, these biohybrids effectively suppressed tumor growth, highlighting their potential as a multifunctional therapeutic strategy for cancer treatment.