Flat‐Field Lens Grating Microspectrometer for Spectroscopic Multiplex Bioassay

Spectroscopic multiplex bioassay allows the rapid and simultaneous detection of various biomarkers in biomedical applications. The high cost and bulky configuration of conventional spectrometers hinder the decentralization of biomedical instruments for point‐of‐care diagnostics. Here a flat‐field lens grating‐based microspectrometer (FLG‐µSPEC) is reported for continuous detection of multi‐target nucleic acid amplification. FLG‐µSPEC features the vertical integration of microslit, integrated flat‐field lens and transmission grating (FLG), concave mirror, and CMOS line sensor. FLG effectively corrects the field curvature by flattening the focal plane of dispersed wavelengths and also facilitates compact module packaging. FLG‐µSPEC module is precisely assembled into a dimension of 10 mm × 16 mm × 10 mm. The average spectral resolution exhibits 3.4 ± 0.9 nm over an operating range of 500 to 950 nm. A spectral detection system utilizing FLG‐µSPEC demonstrates the amplification of lambda DNA (𝜆‐DNA) for each target, exhibiting a high correlation with the obtained result from a conventional real‐time PCR (qPCR) machine. Furthermore, multiplex qPCR analysis using FLG‐µSPEC and spectral deconvolution successfully demonstrates simultaneous and accurate quantification of three different targets. The FLG‐µSPEC module offers diverse on‐demand analytical applications, including not only multiplex bioassay but also environmental monitoring.