A two-photon fluorescence labelling probe (LP) was synthesised, and LP-Ag was obtained by LP labelling the N-protein antigen (Ag) of COVID-19. LP-Ag was made into an immunochromatographic strip. When a blood sample was added to the sample hole of the test card, it would move forward along the nitrocellulose (NC) film. If the sample contained IgM, the IgM bound to LP-Ag and formed an M line with the coated mouse anti-human IgM antibody, giving a positive response to the presence of IgM of COVID-19. The sensitivity, specificity, and accuracy of the immunochromatographic strip based on the LP was compared with those of the nucleic acid detection method and the colloidal gold method, proving it to be much simpler than the nucleic acid detection method, which can greatly shorten the detection period, and to be much more stable than the colloidal gold method, which can overcome uncertainty. LP-Ag can be used to image lung tissue with COVID-19 by two-photon fluorescence microscopy (TFM).

合成了双光子荧光标记探针（LP），通过LP标记COVID-19的N蛋白抗原（Ag）获得了LP-Ag。将LP-Ag制成免疫层析条。将血液样本添加到测试卡的样本孔后，它将沿硝酸纤维素（NC）膜向前移动。如果样品中包含IgM，则IgM与LP-Ag结合并与被包被的小鼠抗人IgM抗体形成M系，从而对COVID-19的IgM的存在产生阳性反应。将基于LP的免疫层析条的灵敏度，特异性和准确性与核酸检测方法和胶体金法的灵敏度，特异性和准确性进行了比较，证明它比核酸检测方法简单得多，可以大大缩短检测时间时期，并且比胶体金法要稳定得多，可以克服不确定性。LP-Ag可用于通过双光子荧光显微镜（TFM）对COVID-19的肺组织进行成像。