Close

Pocket MUSE: an affordable, versatile and high performance fluorescence microscope using a smartphone

Yehe Liu, Andrew M. Rollins, Richard M. Levenson, Farzad Fereidouni, Michael W. Jenkins

Preprint posted on 8 September 2020 https://www.biorxiv.org/content/10.1101/2020.08.28.273094v2

Article now published in Communications Biology at http://dx.doi.org/10.1038/s42003-021-01860-5

Pocket MUSE and smartphone multi-tasking.

Selected by Mariana De Niz

Categories: cell biology, epidemiology

Background

Smartphone microscopes can be effective tools for a broad range of imaging applications. Particularly, smartphone microscopes have proven to be useful in contexts where access to benchtop microscopes is limited. At present, however, smartphone microscope designs face a tradeoff between cost, imaging performance and functionality. Moreover, the advantages of smartphone-based microscopy are hindered by the need of sometimes complex sample preparation. To address these limitations, in their work Liu et al (1) introduce Pocket Microscopy with Ultraviolet Surface Excitation (MUSE).

Figure 1. Images acquired using Pocket MUSE (Ref 1, provided by Michael Jenkins).

Key findings and developments

Overview of Pocket MUSE basic design

This prototype is fabricated from readily available low-cost electronics, and is based on a small optical module that attaches over the rear lens of the smartphone, and enables multichannel fluorescence over a 10x field of view. It consists of only 4 major components: an objective lens, a sample holder, UV LED light sources (powered directly with the smartphone battery via the USB port through a step regulator), and a base plate.

Beyond this, a challenge for portability, is the need to develop versatile sample preparation techniques, without sacrificing the applicability of smartphone microscopes. To address some of the main hindrances, including the need for tissue sectioning, the authors explored the use of ultraviolet illumination, which is strongly absorbed by biological structures but can only penetrate a few microns deep. Without subsurface signals contributing to blur and background, this eliminates the need to prepare flat thin sections for mobile setups. As sub-285 nm UV light is blocked by common optical materials, it is unnecessary to filter out the excitation light with designated filters, making it possible to capture the entire visible range of the emitted light with an RGB camera in a single shot. Another limitation addressed by Pocket MUSE is that compact smartphones have very small working distances. This makes it difficult to fit most conventional sub-285nm light-emitting diodes (LEDs). To overcome this challenge, Pocket MUSE is designed to deliver light using frustrated total internal reflection (TIR) through a UVC transparent optical window, which is also the sample holder pre-aligned at the focus of the smartphone microscope objective. This results in uniform illumination of the full field of view, and eliminates the need for a focusing system. As a further step, the authors improved Pocket MUSE resolution in order to allow visualization of sub-cellular structures.

Pocket MUSE is designed to take quality images while holding the phone in any orientation with one hand, which is convenient for field for applications, where a stable working bench is not always available. Following use, the sample holder can be easily cleaned, either while attached to the device, or detaching from it.

Sample preparation

In addition to the optical configuration, Pocket MUSE is compatible with a series of simple, portable and user-friendly sample preparation strategies that can be directly implemented for various microscopy applications.

Slide-free histology is one of the best established MUSE applications, and therefore this was tested in the Pocket MUSE design here presented by the authors. The authors explored single-dip staining followed by a brief tap-water washing step, and demonstrated high image contrast in various tissue samples. Comparable to resolution achievable by a 10x objective, basic staining for use with Pocket MUSE allows identification of sub-cellular structures such as nuclei, and is therefore already useful for various histology-based applications. Moreover, a color remapping technique could be implemented to mimic the color contrast of conventional H&E staining. Also, conventional immunohistochemistry (IHC) staining can be used for imaging tissues using Pocket MUSE. In terms of fluorescence imaging, overnight staining allowed the use of fluorophore-conjugated antibodies, and signal from multiple fluorophores can be separated by unmixing the RGB channels.

Proof of concept

The authors demonstrated the use of Pocket MUSE for imaging various plants and other environmental samples. They also explored the use of bright-field and hybrid imaging on a blood-smear. Trans-illumination BF microscopy can be used by directing the sample holder towards a bright diffusive surface in the far field, using regular room light or natural light as illumination. This can be used in combination with fluorescent dyes targeting the nucleus to identify white blood cells. The authors also explored the use of Pocket MUSE for mucosal smear imaging, of a sample collected using a cotton swab and dipped in dyes. MUSE fluorescence results showed high contrast between cell bodies nuclei ad background. Interestingly, Pocket MUSE allowed cells to be imaged directly from the cotton fiber matrices, and a large population of cells could be visualized by simply repositioning the swab. Finally, the authors explored the possibility of visualizing bacteria using Pocket MUSE. They found that although individual bacteria are smaller than the resolution limit of Pocket MUSE, they can be visualized if sparsely dispersed in a fluid sample. Moreover, Pocket MUSE could differentiate different populations of microorganisms for example, stained with different dyes.

What I like about this preprint

             I am a big supporter of open science initiatives in all senses. The work presented here makes it possible for many people to access the microscopic world. Moreover, having worked in field settings, I think the possibility of using this setup for screening and diagnostics has great potential, as it could potentially allow the integration of imaging with other tools currently implemented in mobile devices (such as geographical information systems used for epidemiology).

References

  1. Liu et al, Pocket MUSE: an affordable, versatile and high performance fluorescence microscope using a smartphone, bioRxiv, 2020

 

 

Posted on: 2 December 2020

doi: https://doi.org/10.1242/prelights.26115

Read preprint (No Ratings Yet)

Author's response

Yehe Liu and Michael Jenkins shared

1. What are the main limitations that you would point at the current Pocket MUSE setup in terms of samples that can be imaged, illumination needs, information storage, image processing, etc.? And therefore what would be useful next steps to implement to fully adapt Pocket MUSE as a tool for field studies?

A large variety of samples can be quickly and conveniently imaged with Pocket MUSE. With our current setup, we believe there are many potential applications. Specific applications may require greater fields of view or resolution, which should be achievable by changing our design. Also, our first Pocket MUSE prototype is not optimized for rugged use in the field. Future designs will focus on developing a more robust device that holds up under harsh conditions. Finally, specialized software may be needed for certain field studies, which we discuss below.

 

2. Following from the question above, is it possible to do image processing on Pocket MUSE, so that indeed the full diagnostic capacity is available within the same device?

As mentioned above, it is certainly possible to build specific diagnostic capabilities on Pocket MUSE. Pocket MUSE is a smartphone accessory that generates fluorescence microscopy images on the smartphone. You can process and analyze the images generated through Pocket MUSE on any appropriate platform. Today’s smartphones have great processing power. When necessary, any simple data processing on the computer could be easily implemented on smartphones. One step further, for more sophisticated image processing tasks, AI-based image processing and cloud image processing are both options. Alternatively, lightweight image processing tools can also be built on browsers, making it easier to use across different platforms.

 

3. For conventional tests that you have described in your work, have you envisaged building apps compatible with Pocket MUSE for basic image processing depending on the sample collected and the target analysis?

As we are looking for key applications of Pocket MUSE, we are certainly interested in build specific imaging apps. As there are many open-source image processing tools for smartphones, it is possible and convenient to use these as starting points for Pocket MUSE image processing and analysis. Specifically for Pocket MUSE, we have also envisaged building a universal programming library for data preprocessing because MUSE images are slightly different from typical smartphone photographs and microscope images. Certain image processing tasks like automatic color balance, channel unmixing, and color remapping need to be specialized for Pocket MUSE images.

Have your say

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Sign up to customise the site to your preferences and to receive alerts

Register here

preLists in the cell biology category:

‘In preprints’ from Development 2022-2023

A list of the preprints featured in Development's 'In preprints' articles between 2022-2023

 



List by Alex Eve, Katherine Brown

preLights peer support – preprints of interest

This is a preprint repository to organise the preprints and preLights covered through the 'preLights peer support' initiative.

 



List by preLights peer support

The Society for Developmental Biology 82nd Annual Meeting

This preList is made up of the preprints discussed during the Society for Developmental Biology 82nd Annual Meeting that took place in Chicago in July 2023.

 



List by Joyce Yu, Katherine Brown

CSHL 87th Symposium: Stem Cells

Preprints mentioned by speakers at the #CSHLsymp23

 



List by Alex Eve

Journal of Cell Science meeting ‘Imaging Cell Dynamics’

This preList highlights the preprints discussed at the JCS meeting 'Imaging Cell Dynamics'. The meeting was held from 14 - 17 May 2023 in Lisbon, Portugal and was organised by Erika Holzbaur, Jennifer Lippincott-Schwartz, Rob Parton and Michael Way.

 



List by Helen Zenner

9th International Symposium on the Biology of Vertebrate Sex Determination

This preList contains preprints discussed during the 9th International Symposium on the Biology of Vertebrate Sex Determination. This conference was held in Kona, Hawaii from April 17th to 21st 2023.

 



List by Martin Estermann

Alumni picks – preLights 5th Birthday

This preList contains preprints that were picked and highlighted by preLights Alumni - an initiative that was set up to mark preLights 5th birthday. More entries will follow throughout February and March 2023.

 



List by Sergio Menchero et al.

CellBio 2022 – An ASCB/EMBO Meeting

This preLists features preprints that were discussed and presented during the CellBio 2022 meeting in Washington, DC in December 2022.

 



List by Nadja Hümpfer et al.

Fibroblasts

The advances in fibroblast biology preList explores the recent discoveries and preprints of the fibroblast world. Get ready to immerse yourself with this list created for fibroblasts aficionados and lovers, and beyond. Here, my goal is to include preprints of fibroblast biology, heterogeneity, fate, extracellular matrix, behavior, topography, single-cell atlases, spatial transcriptomics, and their matrix!

 



List by Osvaldo Contreras

EMBL Synthetic Morphogenesis: From Gene Circuits to Tissue Architecture (2021)

A list of preprints mentioned at the #EESmorphoG virtual meeting in 2021.

 



List by Alex Eve

FENS 2020

A collection of preprints presented during the virtual meeting of the Federation of European Neuroscience Societies (FENS) in 2020

 



List by Ana Dorrego-Rivas

Planar Cell Polarity – PCP

This preList contains preprints about the latest findings on Planar Cell Polarity (PCP) in various model organisms at the molecular, cellular and tissue levels.

 



List by Ana Dorrego-Rivas

BioMalPar XVI: Biology and Pathology of the Malaria Parasite

[under construction] Preprints presented at the (fully virtual) EMBL BioMalPar XVI, 17-18 May 2020 #emblmalaria

 



List by Dey Lab, Samantha Seah

1

Cell Polarity

Recent research from the field of cell polarity is summarized in this list of preprints. It comprises of studies focusing on various forms of cell polarity ranging from epithelial polarity, planar cell polarity to front-to-rear polarity.

 



List by Yamini Ravichandran

TAGC 2020

Preprints recently presented at the virtual Allied Genetics Conference, April 22-26, 2020. #TAGC20

 



List by Maiko Kitaoka et al.

3D Gastruloids

A curated list of preprints related to Gastruloids (in vitro models of early development obtained by 3D aggregation of embryonic cells). Updated until July 2021.

 



List by Paul Gerald L. Sanchez and Stefano Vianello

ECFG15 – Fungal biology

Preprints presented at 15th European Conference on Fungal Genetics 17-20 February 2020 Rome

 



List by Hiral Shah

ASCB EMBO Annual Meeting 2019

A collection of preprints presented at the 2019 ASCB EMBO Meeting in Washington, DC (December 7-11)

 



List by Madhuja Samaddar et al.

EMBL Seeing is Believing – Imaging the Molecular Processes of Life

Preprints discussed at the 2019 edition of Seeing is Believing, at EMBL Heidelberg from the 9th-12th October 2019

 



List by Dey Lab

Autophagy

Preprints on autophagy and lysosomal degradation and its role in neurodegeneration and disease. Includes molecular mechanisms, upstream signalling and regulation as well as studies on pharmaceutical interventions to upregulate the process.

 



List by Sandra Malmgren Hill

Lung Disease and Regeneration

This preprint list compiles highlights from the field of lung biology.

 



List by Rob Hynds

Cellular metabolism

A curated list of preprints related to cellular metabolism at Biorxiv by Pablo Ranea Robles from the Prelights community. Special interest on lipid metabolism, peroxisomes and mitochondria.

 



List by Pablo Ranea Robles

BSCB/BSDB Annual Meeting 2019

Preprints presented at the BSCB/BSDB Annual Meeting 2019

 



List by Dey Lab

MitoList

This list of preprints is focused on work expanding our knowledge on mitochondria in any organism, tissue or cell type, from the normal biology to the pathology.

 



List by Sandra Franco Iborra

Biophysical Society Annual Meeting 2019

Few of the preprints that were discussed in the recent BPS annual meeting at Baltimore, USA

 



List by Joseph Jose Thottacherry

ASCB/EMBO Annual Meeting 2018

This list relates to preprints that were discussed at the recent ASCB conference.

 



List by Dey Lab, Amanda Haage
Close