Modern Trends in Imaging VIII: Lensfree Computational Microscopy Tools for Cell and Tissue Imaging at the Point-of-Care and in Low-Resource Settings

Abstract

The recent revolution in digital technologies and information processing methods present important opportunities to transform the way optical imaging is performed, particularly toward improving the throughput of microscopes while at the same time reducing their relative cost and complexity. Lensfree computational microscopy is rapidly emerging toward this end, and by discarding lenses and other bulky optical components of conventional imaging systems, and relying on digital computation instead, it can achieve both reflection and transmission mode microscopy over a large field-of-view within compact, cost-effective and mechanically robust architectures. Such high throughput and miniaturized imaging devices can provide a complementary toolset for telemedicine applications and point-of-care diagnostics by facilitating complex and critical tasks such as cytometry and microscopic analysis of e.g., blood smears, Pap tests and tissue samples. In this article, the basics of these lensfree microscopy modalities will be reviewed, and their clinically relevant applications will be discussed.

High-throughput monitoring of major cell functions by means of lensfree video microscopy

“…In addition, they have demonstrated the possibility of coupling lensfree imaging with other imaging modalities, e.g. fluorescence and reflection measurements17181920. These studies confirm the use of lensfree imaging technique as a pragmatic response to the increasing complexity of imaging systems, primarily because of its low cost and ease of use.…”

“…Although several articles demonstrate the application of lensfree technique to cell imaging1220212223242526, none of them show the possibility of using lensfree imaging for continuous cell culture monitoring inside standard incubator for extended period of observation, in a way compatible with standard practices followed by the biologists. Kim et al demonstrated real-time detection of cardiotoxicity using lensfree imaging inside standard incubator, by measuring the variances of beating cardiomyocytes27.…”

Recent approaches for optical smartphone sensing in resource-limited settings: a brief review

“…69 Further in-depth discussion of smartphone microscopy can be found in other topic-specic reviews. [108][109][110][111] Challenges and future needs Overall, perhaps the most basic challenge in smartphone optical sensing is interference from uncontrolled or uneven lighting, which can fundamentally detract from the raw signal being detected. Common control measures include the use of enclosed lighting and imaging attachments for the smartphone, as well as collimating lenses or optical bers to reduce light dispersion.…”

Mkit: A cell migration assay based on microfluidic device and smartphone

“…A highly integrated portable and robotically controlled live cell imaging system was employed for cell migration assay in a microfluidic device (Saito et al 2016). In addition, USB microscopes or webcams were also used for functional cell and tissue imaging, which significantly lower the costs while maintaining adequate imaging performance (Isikman et al 2012;Kim et al 2011;Kim et al 2012;Lynch et al 2014;Walzik et al 2015). We have previously performed cell chemotaxis test using a USB microscope based portable system and a smartphone for remote data monitoring (Wu et al 2014).…”