Smartphone-based multi-contrast microscope using color-multiplexed illumination

Daeseong Jung,Suho Ryu,Soocheol Kim,Jong-Seok Lee,Wonchan Lee,Chulmin Joo,Jun-Ho Choi

doi:10.1038/s41598-017-07703-w

Abstract

We present a portable multi-contrast microscope capable of producing bright-field, dark-field, and differential phase contrast images of thin biological specimens on a smartphone platform. The microscopy method is based on an imaging scheme termed “color-coded light-emitting-diode (LED) microscopy (cLEDscope),” in which a specimen is illuminated with a color-coded LED array and light transmitted through the specimen is recorded by a color image sensor. Decomposition of the image into red, green, and blue colors and subsequent computation enable multi-contrast imaging in a single shot. In order to transform a smartphone into a multi-contrast imaging device, we developed an add-on module composed of a patterned color micro-LED array, specimen stage, and miniature objective. Simple installation of this module onto a smartphone enables multi-contrast imaging of transparent specimens. In addition, an Android-based app was implemented to acquire an image, perform the associated computation, and display the multi-contrast images in real time. Herein, the details of our smartphone module and experimental demonstrations with various biological specimens are presented.

Highlights

Microscopes constitute one of the most commonly employed equipment in biology and medicine[1]
Operation of our mobile multi-contrast microscope is based on the previously demonstrated microscopy scheme termed “color-coded LED microscopy21”. (Fig. 1) In cLEDscope, a color LED array is used as the light source, and is placed at a certain distance from the specimen plane, such that its position is approximately located in the Fourier plane of the specimen plane
The pattern consists of two half circles allocated to red and blue, while the outer circle is assigned to green

Summary

Introduction

Microscopes constitute one of the most commonly employed equipment in biology and medicine[1]. Philips et al.[14] demonstrated a multi-contrast microscope on a smartphone platform capable of generating BF, DF, and differential phase contrast[15,16,17,18,19,20] (DPC) images. In this method, a programmable light-emitting-diode (LED) array in a domed arrangement illuminates the specimen at different angles. Synchronized image acquisition with the smartphone camera module and subsequent computation facilitate BF, DF, and DPC imaging The application of this method, requires synchronized operation of the external LED light source and image sensor, corresponding to relatively high implementation complexity. Having a compact design and exhibiting robust performance, our proposed microscope is likely to constitute an ideal imaging tool for educational purposes as well as diagnostics in resource-limited settings

Methods

Results

Conclusion