Lanthanide-doped upconversion nanoparticles (UCNPs) have gained more attention from researchers due to their unique properties of photon conversion from an excitation/incident wavelength to a more suitable emission wavelength at a designated site, thus improving the scope in the life sciences field. Due to their fascinating and unique optical properties, UCNPs offer attractive opportunities in theranostics for early diagnostics and treatment of deadly diseases such as cancer. Also, several efforts have been made on emerging approaches for the fabrication and surface functionalization of luminescent UCNPs in optical biosensing applications using various infrared excitation wavelengths. In this review, we discussed the recent advancements of UCNP-based analytical chemistry approaches for sensing and theranostics using a 980 nm laser as the excitation source. The key analytical merits of UNCP-integrated fluorescence analytical approaches for assaying a wide variety of target analytes are discussed. We have described the mechanisms of the upconversion (UC) process, and the application of surface-modified UCNPs for in vitro/in vivo bioimaging, photodynamic therapy (PDT), and photothermal therapy (PTT). Based on the latest scientific achievements, the advantages and disadvantages of UCNPs in biomedical and optical applications are also discussed to overcome the shortcomings and to improve the future study directions. This review delivers beneficial practical information of UCNPs in the past few years, and insights into their research in various fields are also discussed precisely.

中文翻译：

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上转换纳米粒子在分析和生物医学科学中的应用：综述

镧系元素掺杂上转换纳米粒子（UCNPs）因其独特的光子从激发/入射波长转换为指定位置更合适的发射波长的特性而受到研究人员的更多关注，从而改善了生命科学领域的范围。由于其引人入胜且独特的光学特性，UCNPs 在治疗诊断学中为癌症等致命疾病的早期诊断和治疗提供了极具吸引力的机会。此外，已经对使用各种红外激发波长的光学生物传感应用中发光 UCNP 的制造和表面功能化的新兴方法进行了一些努力。在本次审查中，我们讨论了使用 980 nm 激光作为激发源的基于 UCNP 的分析化学方法在传感和治疗诊断方面的最新进展。讨论了用于分析多种目标分析物的 UNCP 集成荧光分析方法的主要分析优点。我们已经描述了上转换 (UC) 过程的机制，以及表面改性 UCNPs 在体外/体内生物成像、光动力疗法 (PDT) 和光热疗法 (PTT)。基于最新的科学成果，还讨论了UCNPs在生物医学和光学应用中的优势和劣势，以克服这些不足，完善未来的研究方向。这篇综述提供了过去几年 UCNPs 的有益实践信息，并准确讨论了他们在各个领域的研究见解。