Department of Electrical and Computer Engineering, School of Engineering, Rutgers, The State University of New Jersey, USA.
Global Health Institute, Rutgers, The State University of New Jersey, New Brunswick, USA.
Lab Chip. 2022 Sep 27;22(19):3755-3769. doi: 10.1039/d2lc00589a.
Smartphone fluorescent microscopes (SFM) offer many functional characteristics similar to their benchtop counterparts at a fraction of the cost and have been shown to work for biomarker detection in many biomedical applications. However, imaging and quantification of bioparticles in the sub-micron and nanometer range remains challenging as it requires aggressive robustness and high-performance metrics of the building blocks of SFM. Here, we explored multiple excitation modalities and their performance on the imaging capability of an SFM. Employing spatial positional variations of the excitation source with respect to the imaging sample plane (, parallel, perpendicular, oblique), we developed three distinct SFM variants. These SFM variants were tested using green-fluorescent beads of four different sizes (8.3, 2, 1, 0.8 μm). Optimal excitation voltage range was determined by imaging these beads at multiple excitation voltages to optimize for no data loss and acceptable noise levels for each SFM variant. The SFM with parallel excitation was able to only image 8.3 μm beads while the SFM variants with perpendicular and oblique excitation were able to image all four bead sizes. Relative performance of the SFM variants was quantified by calculating signal difference to noise ratio (SDNR) and contrast to noise ratio (CNR) from the captured images. SFM with oblique excitation generated the highest SDNR and CNR values, whereas, for power consumption, SFM with perpendicular excitation generated the best results. This study sheds light on significant findings related to performance of SFM systems and their potential utility in biomedical applications involving sub-micron imaging. Similarly, findings of this study are translatable to benchtop microscopy instruments as well as to enhance their imaging performance metrics.
智能手机荧光显微镜 (SFM) 提供了许多与台式显微镜相似的功能特性，但其成本仅为其一小部分，并且已经证明在许多生物医学应用中可用于生物标志物检测。然而，在亚微米和纳米范围内对生物粒子进行成像和定量仍然具有挑战性，因为这需要 SFM 的构建块具有激进的稳健性和高性能指标。在这里，我们探索了多种激发模式及其对 SFM 成像能力的性能。通过相对于成像样品平面采用激发源的空间位置变化（平行、垂直、倾斜），我们开发了三种不同的 SFM 变体。使用四个不同尺寸（8.3、2、1、0.8 μm）的绿色荧光珠测试了这些 SFM 变体。通过在多个激发电压下对这些珠子进行成像，确定了最佳激发电压范围，以优化每个 SFM 变体的无数据丢失和可接受的噪声水平。平行激发的 SFM 仅能够对 8.3 μm 的珠子进行成像，而垂直和倾斜激发的 SFM 变体能够对所有四个珠子尺寸进行成像。通过计算从捕获的图像中获得的信号噪声比 (SDNR) 和对比度噪声比 (CNR)，对 SFM 变体的相对性能进行了量化。具有倾斜激发的 SFM 产生了最高的 SDNR 和 CNR 值，而对于功耗，具有垂直激发的 SFM 产生了最佳结果。这项研究揭示了与 SFM 系统性能相关的重要发现及其在涉及亚微米成像的生物医学应用中的潜在用途。同样，这项研究的发现也可转化为台式显微镜仪器，并可提高其成像性能指标。
