The improvement of nucleic acid probes as vital molecular engineering devices will cause a noteworthy contribution to developments in bioimaging, biosensing, and disorders diagnosis. The molecular beacon (MB) which was designed by Tyagi and Kramer in 1996, are loop-stem hairpin-designed oligonucleotides armed with a quencher and a dye (also named reporter groups) at the 3′ or 5′ ends. This construction allows that MBs in the absence of their target complementary molecules do not fluoresce. Through hybridization with their specific targets a spontaneous configuration change on MBs occur and the dye and quencher separate from each other, resulting in emitting the fluorescence. MBs are effective probes for biosensing because of their extraordinary target-specificity, unique structure, inherent fluorescent signal transduction mechanism, low background fluorescence emission, recognition without separation, and favorable thermodynamic properties. In comparison to other probes (such as linear DNA sequences), MBs with the same number of complementary nucleotides matching their target, are multitasking probes. They have advantages of thermodynamic and photostability, flexible ability for conjugation, higher efficient intrinsic signal switching, and ultra-sensitivity. MBs not only are useful for identifying a nucleic acid target but can also be employed for recognition of various non-nucleic acid goals, including heavy metals and cations, enzymes, cells, ATP, etc. Hence, this review highlights the potential of MBs in the improvement of biosensors and their usage in detection of different analytes such as miRNA, mRNA, cocaine, methamphetamine, actin, thrombin, heavy metal and cations and so on.

作为重要分子工程设备的核酸探针的改进将对生物成像，生物传感和疾病诊断的发展做出重要贡献。由Tyagi和Kramer在1996年设计的分子信标（MB）是由环茎发夹设计的寡核苷酸，在3'或5'末端带有猝灭剂和染料（也称为报告基团）。这种构造允许MB在其靶互补分子不存在的情况下不发荧光。通过与它们的特定靶标杂交，MBs发生了自发的构型变化，染料和猝灭剂彼此分离，从而发出荧光。MB具有非凡的靶标特异性，独特的结构，固有的荧光信号转导机制，因此是生物传感的有效探针，低背景荧光发射，无需分离即可识别以及良好的热力学性质。与其他探针（例如线性DNA序列）相比，具有相同数量的互补核苷酸匹配其靶标的MB是多任务探针。它们具有热力学和光稳定性，共轭能力灵活，固有信号切换效率更高和超灵敏的优点。MBs不仅可用于鉴定核酸靶标，还可用于识别各种非核酸目标，包括重金属和阳离子，酶，细胞，ATP等。因此，本综述着重介绍了MBs在生物传感器的改进及其在检测不同分析物（例如miRNA，mRNA，可卡因，甲基苯丙胺，肌动蛋白，凝血酶）中的用途，