Expansion Mini-Microscopy: An Enabling Alternative in Point-of-Care Diagnostics.

Diagnostics play a significant role in health care. In the developing world and low-resource regions the utility for point-of-care (POC) diagnostics becomes even greater. This need has long been recognized, and diagnostic technology has seen tremendous progress with the development of portable instrumentation such as miniature imagers featuring low complexity and cost. However, such inexpensive devices have not been able to achieve a resolution sufficient for POC detection of pathogens at very small scales, such as single-cell parasites, bacteria, fungi, and viruses. To this end, expansion microscopy (ExM) is a recently developed technique that, by physically expanding preserved biological specimens through a chemical process, enables super-resolution imaging on conventional microscopes and improves imaging resolution of a given microscope without the need to modify the existing microscope hardware. Here we review recent advances in ExM and portable imagers, respectively, and discuss the rational combination of the two technologies, that we term expansion mini-microscopy (ExMM). In ExMM, the physical expansion of a biological sample followed by imaging on a mini-microscope achieves a resolution as high as that attainable by conventional high-end microscopes imaging non-expanded samples, at significant reduction in cost. We believe that this newly developed ExMM technique is likely to find widespread applications in POC diagnostics in resource-limited and remote regions by expanded-scale imaging of biological specimens that are otherwise not resolvable using low-cost imagers.

[1]  Aydogan Ozcan,et al.  Field-portable wide-field microscopy of dense samples using multi-height pixel super-resolution based lensfree imaging. , 2012, Lab on a chip.

[2]  Michael J Rust,et al.  Sub-diffraction-limit imaging by stochastic optical reconstruction microscopy (STORM) , 2006, Nature Methods.

[3]  Samuel Schaefer,et al.  Automated, portable, low-cost bright-field and fluorescence microscope with autofocus and autoscanning capabilities. , 2012, Applied optics.

[4]  Aydogan Ozcan,et al.  Field-Portable Pixel Super-Resolution Colour Microscope , 2013, PloS one.

[5]  Derek K. Tseng,et al.  Imaging and sizing of single DNA molecules on a mobile phone. , 2014, ACS nano.

[6]  Hakho Lee,et al.  Digital diffraction analysis enables low-cost molecular diagnostics on a smartphone , 2015, Proceedings of the National Academy of Sciences.

[8]  Ali Khademhosseini,et al.  Google Glass-Directed Monitoring and Control of Microfluidic Biosensors and Actuators , 2016, Scientific Reports.

[9]  Aydogan Ozcan,et al.  Wide-field lensless fluorescent microscopy using a tapered fiber-optic faceplate on a chip. , 2011, The Analyst.

[10]  Ali Khademhosseini,et al.  Hybrid Microscopy: Enabling Inexpensive High-Performance Imaging through Combined Physical and Optical Magnifications , 2016, Scientific Reports.

[11]  Paul W. Tillberg,et al.  Striosome–dendron bouquets highlight a unique striatonigral circuit targeting dopamine-containing neurons , 2016, Proceedings of the National Academy of Sciences.

[12]  L. Cai,et al.  In Situ Transcription Profiling of Single Cells Reveals Spatial Organization of Cells in the Mouse Hippocampus , 2016, Neuron.

[13]  Edward S. Boyden,et al.  Expansion microscopy , 2015, Science.

[14]  Ali Khademhosseini,et al.  Nano/Microfluidics for diagnosis of infectious diseases in developing countries. , 2010, Advanced drug delivery reviews.

[15]  C. Moseke,et al.  Reaction kinetics of dual setting α-tricalcium phosphate cements , 2015, Journal of Materials Science: Materials in Medicine.

[16]  Derek Tseng,et al.  Targeted DNA sequencing and in situ mutation analysis using mobile phone microscopy , 2017, Nature Communications.

[17]  X. Zhuang,et al.  Spatially resolved, highly multiplexed RNA profiling in single cells , 2015, Science.

[18]  Ali Khademhosseini,et al.  Lens-Free Imaging for Biological Applications , 2012, Journal of laboratory automation.

[19]  Joshua C Vaughan,et al.  Expansion microscopy with conventional antibodies and fluorescent proteins , 2016, Nature Methods.

[20]  Aydogan Ozcan,et al.  Field-portable lensfree tomographic microscope. , 2011, Lab on a Chip.

[21]  Timur Zhiyentayev,et al.  Single-cell in situ RNA profiling by sequential hybridization , 2014, Nature Methods.

[22]  James Clements,et al.  Foldscope: Origami-Based Paper Microscope , 2014, PloS one.

[23]  Yibo Zhang,et al.  Wide-field computational imaging of pathology slides using lens-free on-chip microscopy , 2014, Science Translational Medicine.

[24]  A. Ozcan,et al.  Ultra wide-field lens-free monitoring of cells on-chip. , 2008, Lab on a chip.

[25]  R. P. Thompson,et al.  Confocal microscopy of thick sections from acrylamide gel embedded embryos , 1995, Microscopy research and technique.

[26]  Y. S. Zhang,et al.  A cost-effective fluorescence mini-microscope for biomedical applications. , 2015, Lab on a chip.

[27]  Allison M Sheen,et al.  Reagent-free and portable detection of Bacillus anthracis spores using a microfluidic incubator and smartphone microscope. , 2015, The Analyst.

[28]  Edward S Boyden,et al.  Protein-retention expansion microscopy of cells and tissues labeled using standard fluorescent proteins and antibodies , 2016, Nature Biotechnology.

[29]  Kwanghun Chung,et al.  Multiplexed and scalable super-resolution imaging of three-dimensional protein localization in size-adjustable tissues , 2016, Nature Biotechnology.

[30]  Derek Tseng,et al.  Compact, light-weight and cost-effective microscope based on lensless incoherent holography for telemedicine applications. , 2010, Lab on a chip.

[31]  Hazen P Babcock,et al.  High-throughput single-cell gene-expression profiling with multiplexed error-robust fluorescence in situ hybridization , 2016, Proceedings of the National Academy of Sciences.

[32]  Y. Cohen,et al.  Characterization of inhomogeneous polyacrylamide hydrogels , 1992 .

[33]  Long Cai,et al.  Single cell systems biology by super-resolution imaging and combinatorial labeling , 2012, Nature Methods.

[34]  Ali Khademhosseini,et al.  A mini-microscope for in situ monitoring of cells. , 2012, Lab on a chip.

[35]  A. Gamal,et al.  Miniaturized integration of a fluorescence microscope , 2011, Nature Methods.

[36]  S. Hell,et al.  Stimulated emission depletion (STED) nanoscopy of a fluorescent protein-labeled organelle inside a living cell , 2008, Proceedings of the National Academy of Sciences.

[37]  Aydogan Ozcan,et al.  High-throughput and label-free single nanoparticle sizing based on time-resolved on-chip microscopy. , 2015, ACS nano.

[38]  D. Grijpma,et al.  Tissue adhesives for meniscus tear repair: an overview of current advances and prospects for future clinical solutions , 2016, Journal of Materials Science: Materials in Medicine.

[39]  Edward S Boyden,et al.  Nanoscale Imaging of RNA with Expansion Microscopy , 2016, Nature Methods.

[40]  David E. Williams,et al.  Point of care diagnostics: status and future. , 2012, Analytical chemistry.

[41]  A. Ozcan,et al.  Holographic pixel super-resolution in portable lensless on-chip microscopy using a fiber-optic array. , 2011, Lab on a chip.

[42]  Kaikai Guo,et al.  FPscope: a field-portable high-resolution microscope using a cellphone lens. , 2014, Biomedical optics express.

[43]  Mark C. Pierce,et al.  Portable, Battery-Operated, Low-Cost, Bright Field and Fluorescence Microscope , 2010, PloS one.

[44]  Christophe Zimmer,et al.  smiFISH and FISH-quant – a flexible single RNA detection approach with super-resolution capability , 2016, Nucleic acids research.

[45]  Hongying Zhu,et al.  Cost-effective and compact wide-field fluorescent imaging on a cell-phone. , 2011, Lab on a chip.

[46]  Gerard L. Coté,et al.  Malaria Diagnosis Using a Mobile Phone Polarized Microscope , 2015, Scientific Reports.

[47]  N. Engel,et al.  Point-of-Care Testing for Infectious Diseases: Diversity, Complexity, and Barriers in Low- And Middle-Income Countries , 2012, PLoS medicine.