微小RNA（miRNA）是癌症早期诊断的重要生物标志物，然而，对miRNA检测的敏感和方便的方法仍然是一个挑战。在这里，我们使用从灵芝孢子中纯化的天然生物聚合物孢粉做为一种等温扩增（杂交链反应，HCR）的底物。孢粉囊（SP）促进了HCR，并且形成了比氧化石墨烯（GO）和碳纳米管（CNTs）更长更丰富的双链DNA（dsDNA）。富含水分的孢粉囊的纳米孔结构提供了一个湿润环境，显著增强了DNA的杂交效率。我们构建了一个超灵敏的荧光生物传感器来检测miR-155。在SP上高效的HCR扩增引导了miR-155的超低检测限（1 aM）和宽线性范围（1 aM-10 fM，R2 = 0.99）。此外，我们的荧光生物传感器能够对miRNA突变体具有高选择性。该生物传感器在人体血清中也具有高灵敏度（检测限为10 aM）。与GO和CNTs相比，它吸附较少的血清蛋白，从而减少了非特异性吸附所引起的干扰。我们的研究将促进将基于SP的生物传感器在医学应用中的推广。Copyright © 2023 Elsevier B.V. All rights reserved.

MicroRNA (miRNA) is an important biomarker for early diagnosis of cancers. However, sensitive and convenient methods for miRNA detection remain a challenge. Here, we use a natural biopolymer sporopollenin purified from Ganoderma lucidum spores as a substrate for isothermal amplification (hybridization chain reaction, HCR). Sporopollenin capsules (SP) promotes HCR and forms longer and more abundant double-stranded DNA (dsDNA) than graphene oxide (GO) and carbon nanotubes (CNTs). The nanoporous structure of sporopollenin capsules containing abundant water provides a hydrous environment and enhances the hybridization efficiency of DNA significantly. We construct an ultrasensitive fluorescent biosensor to detect miR-155. The efficient HCR amplification on SP leads to an ultralow detection limit of 1 aM for miR-155 and a wide linear range of 1 aM-10 fM (R2 = 0.99). Furthermore, our fluorescence biosensor can discriminate miRNA mutants with high selectivity. This biosensor is also highly sensitive in human serum (detection limit 10 aM). It adsorbs less serum protein than GO and CNTs, thus minimizing the interference caused by the non-specific adsorption. Our study would promote medical application of SP-based biosensor in the future.Copyright © 2023 Elsevier B.V. All rights reserved.