关键词: 遗传编码荧光探针, 荧光蛋白, 荧光RNA, 分子成像, 疾病诊断

Abstract:

In recent years, significant advances have been made in the field of genetically encoded fluorescent sensors. Fluorescent protein-based sensors have seen continuous improvements in performance, with researchers employing protein engineering techniques to develop brighter and more photostable fluorescent protein variants, as well as extending their emission spectra into the far-red region for deeper tissue imaging. Concurrently, innovative sensing mechanisms have emerged, such as the incorporation of genetically encoded unnatural fluorescent amino acids to construct miniaturized fluorescent reporter molecules, and strategies utilizing protein conformational changes or Förster resonance energy transfer (FRET) to sensitively detect biological signals. Researchers have also developed highly specific fluorescent sensors targeting particular biomarkers, including genetically encoded sensors for detecting ions, metabolites, or enzyme activities, providing powerful tools for precise monitoring of cellular physiological processes. Meanwhile, RNA fluorescent aptamers, another major category of genetically encoded sensors, have achieved substantial progress in structural optimization and functional expansion. Newly screened and engineered fluorescent aptamers exhibit enhanced affinity and specificity toward their fluorescent ligands, significantly improving fluorescence activation efficiency. Certain aptamer-ligand complexes now exhibit brightness comparable to, or even exceeding, traditional fluorescent proteins. Various combinations of aptamers and fluorophores currently cover emission spectra ranging from visible to near-infrared. These RNA-based sensors have successfully enabled the labeling and visualization of endogenous RNA molecules in living cells, facilitating real-time tracking of RNA localization and dynamics. Furthermore, combining fluorescent aptamers with small-molecule recognition aptamers has enabled the creation of novel fluorescent "switch" sensors, whose fluorescence is activated through conformational changes triggered by the presence of specific metabolites. Both types of genetically encoded sensors demonstrate substantial value in disease diagnosis. For instance, fluorescent protein-based biosensors can monitor abnormal fluctuations of intracellular metabolites and signaling molecules, such as glucose or ATP levels, aiding in the elucidation of metabolic characteristics in diseases like diabetes and cancer. Utilizing improved near-infrared fluorescent proteins and fluorescent aptamers in vivo allows deeper tissue penetration and facilitates early detection of pathological changes, such as tumors. Additionally, fluorescent sensors specifically designed for pathological states-such as oxidative stress, pH imbalance, or particular enzyme activities—can directly report disease signals at the cellular level, supporting precise diagnostics. Overall, these advancements significantly enhance the sensitivity and specificity of biological imaging and molecular diagnostics. Looking forward, as sensor performance continues to improve and new sensing principles emerge, genetically encoded fluorescent sensors will play increasingly prominent roles in more complex biological systems and clinical diagnostics, exhibiting tremendous potential for future applications.

Key words: genetically encoded fluorescent sensors, fluorescent proteins, fluorescent aptamers, molecular imaging, disease diagnosis