Carbon dots (CDs) with incomparable optical properties are promising nanoparticles for biological and medical applications such as imaging, biosensing, and drug delivery. Because their absorption and emission mechanism is not fully understood, the synthesis of CDs with desire optical characteristics is more challenging. Many efforts have been conducted to obtain robust and reproducible methods for blue and green CDs, but there is no controllable procedure for producing permanent red fluorescence emitting CDs. This review discusses various studies evaluating the effective parameters for synthesizing red carbon dots (R-CDs) to obtain a rational and predictable synthesis method for this type of CDs. Following an introduction, the first section covers the main tunable features of R-CDs. A section on R-CDs preparation follows this by selecting suitable synthesis methods, selecting suitable precursors, computational modeling, statistical optimization, and purifying methods. Several tables are presented that give an overview of each section. The final sections deal with the relationship between the structure of R-CDs and their optical properties, as well as the main nanomedicine applications of R-CDs. The conclusion summarizes the current status, addresses challenges, and gives an outlook on potential future trends.

具有无与伦比光学特性的碳点 (CD) 是用于生物和医学应用（例如成像、生物传感和药物递送）的有前途的纳米粒子。由于尚未完全了解它们的吸收和发射机制，因此合成具有所需光学特性的 CD 更具挑战性。已经进行了许多努力以获得用于蓝色和绿色 CD 的稳健且可重复的方法，但没有用于生产永久性红色荧光 CD 的可控程序。本综述讨论了各种评估合成红碳点 (R-CD) 的有效参数的研究，以获得此类 CD 的合理且可预测的合成方法。在介绍之后，第一部分介绍了 R-CD 的主要可调功能。R-CDs 制备部分通过选择合适的合成方法、选择合适的前体、计算建模、统计优化和纯化方法来遵循这一点。提供了几个表格，概述了每个部分。最后几节讨论了 R-CDs 的结构与其光学性质之间的关系，以及 R-CDs 的主要纳米医学应用。结论总结了当前状态，解决了挑战，并展望了未来的潜在趋势。以及 R-CD 的主要纳米医学应用。结论总结了当前状态，解决了挑战，并展望了未来的潜在趋势。以及 R-CD 的主要纳米医学应用。结论总结了当前状态，解决了挑战，并展望了未来的潜在趋势。