An optical refractive index (RI) nanosensor with a high sensitivity and figure of merit (FOM), good stability, and biocompatibility is of great significance for biological detection and sensing in narrow spaces. However, the current optical RI nanosensors are mainly fabricated using metals, semiconductors, and quartz, which are not biocompatible and are even biotoxic, and often face a trade-off between a high sensitivity and a high FOM. Moreover, the sensors are mainly based on surface plasmon resonance, photonic crystals, fiber grating, etc., and, thus, most of them usually require a laser source with a specific optical wavelength or harsh excitation conditions, which are likely to cause photodamage and are unfavorable for biological applications. Hence, polylactic acid (PLA), a flexible dielectric material with good biocompatibility, is functioned by doping high refractive index quantum dots (QDs) and fabricated as a nanowire RI sensor. Doping the QDs into a PLA nanowire can improve the light confinement ability and then enhance Mie resonant scattering of the PLA nanowire, which is very beneficial to obtain a higher quality factor and then a higher-performance nanowire sensor. Under irradiation of a white light source, a high sensitivity with 833.78 nm/RIU (per refractive index unit) and the highest FOM of 9.64 RIU⁻¹ are obtained. The good reliability and reproducibility of the sensors are further demonstrated. By choosing a proper diameter, the scattering peak of the nanosensor can be tuned into a biofriendly spectral range (600–900 nm), which predicts that the PLA nanowire RI sensors have a great potential in biological microenvironment monitoring, biosensing, and biomedical treatment.

中文翻译：

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使用量子点掺杂的聚乳酸纳米线的基于 Mie 共振散射的折射率传感器

具有高灵敏度和品质因数（FOM）、良好的稳定性和生物相容性的光学折射率（RI）纳米传感器对于狭窄空间的生物检测和传感具有重要意义。然而，目前的光学 RI 纳米传感器主要使用金属、半导体和石英制造，这些材料不具有生物相容性，甚至具有生物毒性，并且经常面临高灵敏度和高 FOM 之间的权衡。此外，传感器主要基于表面等离子体共振、光子晶体、光纤光栅等，因此，它们大多需要特定光波长的激光源或苛刻的激发条件，容易造成光损伤和损伤。不利于生物应用。因此，聚乳酸（PLA），一种具有良好生物相容性的柔性介电材料，通过掺杂高折射率量子点 (QD) 发挥作用，并制成纳米线 RI 传感器。将量子点掺杂到 PLA 纳米线中可以提高光限制能力，进而增强 PLA 纳米线的 Mie 共振散射，这非常有利于获得更高的品质因数和更高性能的纳米线传感器。在白色光源的照射下，具有 833.78 nm/RIU（每折射率单位）的高灵敏度和 9.64 RIU 的最高 FOM得到^-1。进一步证明了传感器的良好可靠性和再现性。通过选择合适的直径，纳米传感器的散射峰可以调整到生物友好的光谱范围（600-900 nm），这预示着 PLA 纳米线 RI 传感器在生物微环境监测、生物传感和生物医学治疗方面具有巨大的潜力。