本文系统介绍了微流激光生化传感机理及其研究进展。基于增益介质调节的微流激光生化传感技术，利用光学微腔内增益介质的数量或状态变化影响激光输出特性；基于微腔调节的微流激光生化传感技术，利用光学微腔性质的变化，引起谐振条件变化，进而引起激光模式、波长或输出方向的变化；基于损耗调节的微流激光生化传感技术，主要包括吸收损耗和散射损耗，待测物或其化学产物对激光产生散射或吸收，使激光强度下降，从而实现生化传感。由于微腔的增敏和激光的放大作用，激光输出特性对腔内生化过程的变化十分敏感，因此微流激光可实现高灵敏、高通量的生化传感。
Optofluidic laser has shown great potential in biochemical sensing. Here in this review, we systematically introduced the sensing mechanism and research progress of optofluidic laser based biochemical sensors. The gain medium regulated optofluidic laser sensing mainly depends on the quantity and state of gain molecules. When the biochemical reaction or molecules change the characteristics of microcavity, the resonance condition changes accordingly, and the change can be reflected and read out in the modes, wavelength and emission direction of lasing light. Furthermore, the biochemical molecules can introduce absorption loss and scattering loss in the laser cavity, causing measurable deterioration in laser intensity. Thanks to the amplification of lasing process and optical microcavity, and the narrow linewidth of laser, the laser output characteristics are ultrasensitive to the subtle changes of biochemical process to achieve high sensitivity and high-throughput biochemical sensing.
[1] Hansch T, Pernier M, Schawlow A. Laser action of dyes in gelatin[J]. IEEE Journal of Quantum Electronics, 1971, 7(1):45-46.
[2] Hansch T W. Edible lasers and other delights of the 1970s[J]. Optics & Photonics News, 2005, 16(2):14-16.
[3] Helbo B, Kristensen A, Menon A. A micro-cavity fluidic dye laser[J]. Journal of Micromechanics and Microengineering, 2003, 13(2):307.
[4] Shivakiran-Bhaktha B N, Bachelard N, Noblin X, et al. Optofluidic random laser[J]. Applied Physics Letters, 2012, 101(15):151101.
[5] Yu J, Liu Y, Wang Y, et al. Optofluidic laser based on a hollow-core negative-curvature fiber[J]. Nanophotonics, 2018, 7(7):1307-1315.
[6] Zhou T, Tang M, Xiang G, et al. Continuous-wave quantum dot photonic crystal lasers grown on on-axis Si (001)[J]. Nature Communications, 2020, 11(1):977.
[7] Moon H J, Chough Y T, An K. Cylindrical microcavity laser based on the evanescent wave coupled gain[J]. Physical Review Letters, 2000, 85(15):3161.
[8] Kazes M, Lewis D Y, Ebenstein Y, et al. Lasing from CdSe/ZnS quantum rods in a cylindrical microcavity[J]. Advanced Materials, 2002, 14(4):317-321.
[9] Schafer J, Mondia J P, Sharma R, et al. Quantum dot microdrop laser[J]. Nano Letters, 2008, 8(6):1709-1712.
[10] Gather M C, Yun S H. Lasing from Escherichia coli bacteria genetically programmed to express green fluorescent protein[J]. Optics Letters, 2011, 36(16):3299-3301.
[11] Lee W, Kim D B, Song M H, et al. Optofluidic ring resonator laser with an edible liquid laser gain medium[J]. Optics Express, 2017, 25(13):14043-14048.
[12] Maecel S, Lewis W, Isla R M B, et al, Monitoring contractility in cardiac tissue with cellular resolution using biointegrated microlasers[J]. Nature Photonics, 2020, 14:452-458.
[13] Malte C G, Seok H Y. Single-cell biological lasers[J]. Nature Photonics, 2011, 5:406-410.
[14] Matjaž H, Seok H Y. Intracellular microlasers[J]. Nature Photonics, 2015, 9:572-576.
[15] Nicola M, Sheldon J J K, Andreas C L, et al. Wavelength-encoded laser particles for massively multiplexed cell tagging[J]. Nature Photonics, 2019, 13:720-727.
[16] Wu X, Oo M K K, Reddy K, et al. Optofluidic laser for dual-mode sensitive biomolecular detection with a large dynamic range[J]. Nature Communications, 2014, 5:3779.
[17] Mao J G, Yang X, Liu Y L, et al. Nanomaterial-enhanced fiber optofluidic laser biosensor for sensitive enzyme detection[J]. Journal of Lightwave Technology, 2020, 38(18):5205-5211.
[18] Gong C Y, Gong Y, Oo M K K, et al. Sensitive sulfide ion detection by optofluidic catalytic laser using horseradish peroxidase (HRP) enzyme[J]. Biosensors and Bioelectronics, 2017, 96:351-357.
[19] Zhang X, Lee W, Fan X. Bio-switchable optofluidic lasers based on DNA Holliday junctions[J]. Lab on a Chip, 2012, 12(19):3673-3675.
[20] Wu J Y, Fan M W, Deng G W, et al. Optofluidic laser explosive sensor with ultralow detectionlimit and large dynamic range using donor-acceptor-donor organic dye[J]. Sensors Actuators B, 2019(298):126830.
[21] Lee W, Fan X D. Intracavity DNA melting analysis with optofluidic lasers[J]. Analytical Chemistry, 2012, 84(21):9558-9563.
[22] Tang S J, Liu Z, Qian Y J, et al. A tunable optofluidic microlaser in a photostable conjugated polymer[J]. Advanced Materials (Deerfield Beach, Fla), 2018, 30(50):e1804556.
[23] Yang X, Shu W, Wang Y, et al. Turbidimetric inhi-bition immunoassay revisited to enhance its sensitivity via an optofluidic laser[J]. Biosensors and Bioelectronics, 2019, 131(15):60-66.
[24] Rui D, Li Y Z, He Y C, et al. Quantitative and sensitive detection of lipase using liquid crystal microfiber biosensor based on whispering-gallery mode[J]. Analyst, 2020(145):7595-7602.
[25] Yang X, Luo Y, Liu Y, et al. Mass production of thin-walled hollow optical fiber enables disposable optofluidic laser immunosensor[J]. Lab on a Chip, 2020, 20(5):923-930.
[26] Gong C Y, Gong Y, Zhao X, et al. Distributed fibre optofluidic laser for chip-scale arrayed biochemical sensing[J]. Lab on a Chip, 2018, 18(18):2741-2748.
