Department of Chemistry and the Institute for Lasers, Photonics, and Biophotonics, University at Buffalo, State University of New York, Buffalo, NY, USA.
Department of Chemical and Biological Engineering, University at Buffalo, State University of New York, Buffalo, NY, USA.
J Nanobiotechnology. 2024 Oct 18;22(1):637. doi: 10.1186/s12951-024-02874-x.
Both lanthanide-containing and fluorine-containing nanomaterials present challenging targets for microbial biosynthesis because these elements are toxic to most bacteria. Here, we overcome these challenges by using an Antarctic Shewanella baltica strain that tolerates these elements and report the first biosynthesis of lanthanide-doped fluoride nanoparticles (NPs) from them. NaYF NPs doped with Er/Yb are prototypical lanthanide-based upconverting nanoparticles (UCNPs) with upconverted luminescence at visible wavelengths under infrared excitation. However, their synthesis employs high precursor concentrations, organic solvents, and elevated temperatures. Microbial biosynthesis offers a greener alternative but has not been explored for these materials. Here, we harness an extremophile S. baltica strain to biosynthesize UCNPs at room temperature, based upon its high tolerance for fluoride and lanthanide ions and the observation that tolerance of lanthanides increased in the presence of fluoride. Our biosynthesis produces electron-dense nanostructures composed of Na, Y, F, Yb, and Er in the bacterial periplasm, adhered to the outer cell membrane, and dispersed extracellularly, which exhibited up-converted emission under 980 nm excitation. This suggests that extracellular or periplasmic mineralization of lanthanides as fluorides protects the bacteria from lanthanide toxicity. Subsequent heating both enhanced upconverted emission from UCNPs and allowed observation of their crystallinity in transmission electron microscopy (TEM). This work establishes the first biosynthesis of NaYF:Yb: Er UCNPs, advancing both nanotechnology and biotechnology.
含镧和含氟的纳米材料都对微生物生物合成提出了挑战，因为这些元素对大多数细菌都有毒性。在这里，我们使用一种能够耐受这些元素的南极希瓦氏菌（Shewanella baltica）菌株克服了这些挑战，并报告了首例镧掺杂氟纳米粒子（NPs）的生物合成。掺铒/镱的 NaYF NPs 是典型的基于镧的上转换纳米粒子（UCNPs），在红外激发下可在可见光波长处实现上转换发光。然而，它们的合成需要使用高浓度的前体、有机溶剂和高温。微生物生物合成提供了一种更环保的替代方法，但尚未针对这些材料进行探索。在这里，我们利用一种极端微生物 S. baltica 菌株在室温下生物合成 UCNPs，这是基于其对氟化物和镧离子的高耐受性，以及在氟化物存在的情况下镧耐受性增加的观察结果。我们的生物合成在细菌周质中产生了由 Na、Y、F、Yb 和 Er 组成的电子致密纳米结构，这些结构附着在细胞膜外，并分散在细胞外，在 980nm 激发下表现出上转换发射。这表明镧作为氟化物的细胞外或周质矿化可以保护细菌免受镧毒性的影响。随后的加热既增强了 UCNPs 的上转换发射，也允许在透射电子显微镜（TEM）中观察到它们的结晶度。这项工作建立了首例 NaYF:Yb:Er UCNPs 的生物合成，推进了纳米技术和生物技术的发展。
