{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,29]],"date-time":"2026-05-29T11:23:56Z","timestamp":1780053836767,"version":"3.54.0"},"reference-count":54,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2021,8,5]],"date-time":"2021-08-05T00:00:00Z","timestamp":1628121600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100006196","name":"Jet Propulsion Laboratory","doi-asserted-by":"publisher","award":["none"],"award-info":[{"award-number":["none"]}],"id":[{"id":"10.13039\/100006196","id-type":"DOI","asserted-by":"publisher"}]},{"name":"National Science Foundation United States","award":["1828793"],"award-info":[{"award-number":["1828793"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Life"],"abstract":"<jats:p>Digital holographic microscopy provides the ability to observe throughout a volume that is large compared to its resolution without the need to actively refocus to capture the entire volume. This enables simultaneous observations of large numbers of small objects within such a volume. We have constructed a microscope that can observe a volume of 0.4 \u00b5m \u00d7 0.4 \u00b5m \u00d7 1.0 \u00b5m with submicrometer resolution (in xy) and 2 \u00b5m resolution (in z) for observation of microorganisms and minerals in liquid environments on Earth and on potential planetary missions. Because environmental samples are likely to contain mixtures of inorganics and microorganisms of comparable sizes near the resolution limit of the instrument, discrimination between living and non-living objects may be difficult. The active motion of motile organisms can be used to readily distinguish them from non-motile objects (live or inorganic), but additional methods are required to distinguish non-motile organisms and inorganic objects that are of comparable size but different composition and structure. We demonstrate the use of passive motion to make this discrimination by evaluating diffusion and buoyancy characteristics of cells, styrene beads, alumina particles, and gas-filled vesicles of micron scale in the field of view.<\/jats:p>","DOI":"10.3390\/life11080793","type":"journal-article","created":{"date-parts":[[2021,8,5]],"date-time":"2021-08-05T09:35:32Z","timestamp":1628156132000},"page":"793","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Microscopic Object Classification through Passive Motion Observations with Holographic Microscopy"],"prefix":"10.3390","volume":"11","author":[{"given":"Devan","family":"Rouzie","sequence":"first","affiliation":[{"name":"Department of Physics, Portland State University, 1719 SW 10th Ave., Portland, OR 97201, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian","family":"Lindensmith","sequence":"additional","affiliation":[{"name":"Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91125, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jay","family":"Nadeau","sequence":"additional","affiliation":[{"name":"Department of Physics, Portland State University, 1719 SW 10th Ave., Portland, OR 97201, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"47","DOI":"10.1023\/A:1013958519734","article-title":"Europa as an Abode of Life","volume":"32","author":"Chyba","year":"2002","journal-title":"Orig. Life Evol. Biosph."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"740","DOI":"10.1089\/ast.2013.1003","article-title":"Science potential from a Europa lander","volume":"13","author":"Pappalardo","year":"2013","journal-title":"Astrobiology"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"678","DOI":"10.1016\/j.asr.2010.11.010","article-title":"Strategies for detection of putative life on Europa","volume":"48","author":"Vorobyova","year":"2011","journal-title":"Adv. Space Res."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"909","DOI":"10.1089\/ast.2008.0265","article-title":"A The Possible Origin and Persistence of Life on Enceladus and Detection of Biomarkers in the Plume","volume":"8","author":"McKay","year":"2008","journal-title":"Astrobiology"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"730","DOI":"10.1089\/ast.2011.0813","article-title":"LIFE: Life Investigation For Enceladus A Sample Return Mission Concept in Search for Evidence of Life","volume":"12","author":"Tsou","year":"2012","journal-title":"Astrobiology"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"876","DOI":"10.1089\/ast.2017.1665","article-title":"Could It Be Snowing Microbes on Enceladus? Assessing Conditions in Its Plume and Implications for Future Missions","volume":"17","author":"Porco","year":"2017","journal-title":"Astrobiology"},{"key":"ref_7","unstructured":"Hand, K.P. (2017, August 10). Report of the Europa Lander Science Definition Team, Available online: https:\/\/europa.nasa.gov\/resources\/58\/europa-lander-study-2016-report\/."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"6372","DOI":"10.1038\/ncomms7372","article-title":"Diverse uncultivated ultra-small bacterial cells in groundwater","volume":"6","author":"Luef","year":"2015","journal-title":"Nat. Commun."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"859","DOI":"10.1089\/ast.2007.0043","article-title":"Fluorescence Microscopy as a Tool for In Situ Life Detection","volume":"8","author":"Nadeau","year":"2008","journal-title":"Astrobiology"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"755","DOI":"10.1089\/ast.2015.1376","article-title":"Microbial Morphology and Motility as Biosignatures for Outer Planet Missions","volume":"16","author":"Nadeau","year":"2016","journal-title":"Astrobiology"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1981","DOI":"10.1128\/AEM.01724-09","article-title":"Agreement, Precision, and Accuracy of Epifluorescence Microscopy Methods for Enumeration of Total Bacterial Numbers","volume":"76","author":"Seo","year":"2010","journal-title":"Appl. Environ. Microbiol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"3","DOI":"10.1111\/j.1574-6941.2005.00003.x","article-title":"Bacterial motility: Links to the environment and a driving force for microbial physics","volume":"55","author":"Mitchell","year":"2006","journal-title":"FEMS Microbiol. Ecol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"761","DOI":"10.1038\/nrmicro3567","article-title":"Live from under the lens: Exploring microbial motility with dynamic imaging and microfluidics","volume":"13","author":"Son","year":"2015","journal-title":"Nat. Rev. Microbiol."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"227","DOI":"10.1007\/BF02540225","article-title":"The influence of cell size on marine bacterial motility and energetics","volume":"22","author":"Mitchell","year":"1991","journal-title":"Microb. Ecol."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"281","DOI":"10.1016\/0022-2836(91)90212-O","article-title":"Characterization of the cytoplasm of Escherichia coli K-12 as a function of external osmolarity. Implications for protein-DNA interactions in vivo","volume":"222","author":"Cayley","year":"1991","journal-title":"J. Mol. Biol."},{"key":"ref_16","unstructured":"Ayres, S.L. (2017). Cell Density (Mass per Unit Volume) of Diatom Cells and Chains in Relation to Their Size, Growth, and Nutritional Condition, University of Maine."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1080\/09670269910001736362","article-title":"Growth and silica content of the diatoms Thalassiosira weissflogii and Navicula salinarum at different salinities and enrichments with aluminium","volume":"34","author":"Vrieling","year":"1999","journal-title":"Eur. J. Phycol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"521","DOI":"10.1016\/0076-6879(88)67058-3","article-title":"Buoyancy and suspension of planktonic cyanobacteria","volume":"167","author":"Oliver","year":"1988","journal-title":"Methods Enzymol."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"2927","DOI":"10.1002\/aic.16138","article-title":"Recombinantly Expressed Gas Vesicles as Nanoscale Contrast Agents for Ultrasound and Hyperpolarized MRI","volume":"64","author":"Farhadi","year":"2018","journal-title":"AIChE J."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"8127","DOI":"10.1021\/acs.nanolett.0c03159","article-title":"Genetically Encoded Phase Contrast Agents for Digital Holographic Microscopy","volume":"20","author":"Farhadi","year":"2020","journal-title":"Nano Lett."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"279","DOI":"10.1016\/0022-2836(79)90281-X","article-title":"Average thickness of the gas vesicle wall in Anabaena flos-aquae","volume":"129","author":"Walsby","year":"1979","journal-title":"J. Mol. Biol."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2118","DOI":"10.1002\/jgrc.20086","article-title":"The settling velocity of mineral, biomineral, and biological particles and aggregates in water","volume":"118","author":"Maggi","year":"2013","journal-title":"J. Geophysical. Res.-Oceans"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"10997","DOI":"10.1021\/la301370y","article-title":"Importance of particle tracking and calculating the mean-squared displacement in distinguishing nanopropulsion from other processes","volume":"28","author":"Dunderdale","year":"2012","journal-title":"Langmuir"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"17367","DOI":"10.1364\/OE.23.017367","article-title":"Robust, compact implementation of an off-axis digital holographic microscope","volume":"23","author":"Wallace","year":"2015","journal-title":"Opt. Express"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Lindensmith, C.A., Rider, S., Bedrossian, M., Wallace, J.K., Serabyn, E., Showalter, G.M., Deming, J.W., and Nadeau, J.L. (2016). A Submersible, Off-Axis Holographic Microscope for Detection of Microbial Motility and Morphology in Aqueous and Icy Environments. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0147700"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"123113","DOI":"10.1063\/1.4904449","article-title":"A Mach-Zender digital holographic microscope with sub-micrometer resolution for imaging and tracking of marine micro-organisms","volume":"85","author":"Kuhn","year":"2014","journal-title":"Rev. Sci. Instrum."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"138","DOI":"10.1002\/biot.201000427","article-title":"Miniaturized lensless imaging systems for cell and microorganism visualization in point-of-care testing","volume":"6","author":"Gurkan","year":"2011","journal-title":"Biotechnol. J."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"A68","DOI":"10.1364\/AO.52.000A68","article-title":"Automated three-dimensional detection and classification of living organisms using digital holographic microscopy with partial spatial coherent source: Application to the monitoring of drinking water resources","volume":"52","author":"Minetti","year":"2013","journal-title":"Appl. Optics"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"342","DOI":"10.1016\/j.pocean.2015.04.016","article-title":"The role of advection in the distribution of plankton populations at a moored 1-D coastal observatory","volume":"137","author":"Cross","year":"2015","journal-title":"Progress Oceanogr."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1002\/lom3.10402","article-title":"Automated plankton classification from holographic imagery with deep convolutional neural networks","volume":"19","author":"Guo","year":"2021","journal-title":"Limnol. Oceanogr. -Methods"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1016\/j.optcom.2014.10.035","article-title":"Digital holographic microscopy for microalgae biovolume assessment","volume":"336","author":"Monaldi","year":"2015","journal-title":"Optics Commun."},{"key":"ref_32","first-page":"18","article-title":"Application of Digital Holographic Microscopy for Automatic Monitoring of Freely Floating Microorganisms","volume":"108","author":"Orzo","year":"2017","journal-title":"Ercim News"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"1613","DOI":"10.1016\/j.optcom.2011.11.077","article-title":"Digital holographic microscopy for detection of Trypanosoma cruzi parasites in fresh blood mounts","volume":"285","author":"Romero","year":"2012","journal-title":"Opt. Commun."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"17512","DOI":"10.1073\/pnas.0704658104","article-title":"Digital holographic microscopy reveals prey-induced changes in swimming behavior of predatory dinoflagellates","volume":"104","author":"Sheng","year":"2007","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_35","first-page":"011010","article-title":"Holographic Imaging Reveals the Mechanism of Wall Entrapment in Swimming Bacteria","volume":"7","author":"Bianchi","year":"2017","journal-title":"Phys. Rev. X"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"10761","DOI":"10.1364\/OE.15.010761","article-title":"Tracking biological microorganisms in sequence of 3D holographic microscopy images","volume":"15","author":"DaneshPanah","year":"2007","journal-title":"Opt. Express"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"084301","DOI":"10.1063\/1.3473937","article-title":"Microbial population dynamics by digital in-line holographic microscopy","volume":"81","author":"Frentz","year":"2010","journal-title":"Rev. Sci. Instrum."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"26","DOI":"10.1007\/s00348-016-2113-0","article-title":"Three-dimensional swimming motility of microorganism in the near-wall region","volume":"57","author":"Lee","year":"2016","journal-title":"Exp. Fluids"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"064004","DOI":"10.1088\/0957-0233\/22\/6\/064004","article-title":"Three-dimensional motion measurements of free-swimming microorganisms using digital holographic microscopy","volume":"22","author":"Lee","year":"2011","journal-title":"Meas. Sci. Technol."},{"key":"ref_40","first-page":"56343","article-title":"Quantifying Microorganisms at Low Concentrations Using Digital Holographic Microscopy (DHM)","volume":"129","author":"Bedrossian","year":"2017","journal-title":"J. Vis. Exp."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"913","DOI":"10.1089\/ast.2016.1616","article-title":"Digital Holographic Microscopy, a Method for Detection of Microorganisms in Plume Samples from Enceladus and Other Icy Worlds","volume":"17","author":"Bedrossian","year":"2017","journal-title":"Astrobiology"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"216","DOI":"10.1002\/andp.18782411005","article-title":"Uber eine besondere Art der Tonerregung","volume":"5","author":"Strouhal","year":"1878","journal-title":"Ann. Phys."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"373","DOI":"10.1146\/annurev-fluid-120710-101156","article-title":"Fluid Mechanics of Planktonic Microorganisms","volume":"44","author":"Guasto","year":"2012","journal-title":"Annu. Rev. Fluid Mech."},{"key":"ref_44","doi-asserted-by":"crossref","unstructured":"Fregoso, S.F., Lima, F., Wallace, J.K., Bedrossian, M., McKeithen, D., Kettenbeil, C., Loya, F., and Lindensmith, C. (2020). DHMx (Digital Holographic Microscope Experience) Software Tool. Digital Holography and Three-Dimensional Imaging, Optical Society of America.","DOI":"10.1364\/DH.2020.HF2G.7"},{"key":"ref_45","doi-asserted-by":"crossref","unstructured":"Mann, C.J., and Kim, M.K. (2006). Quantitative phase-contrast microscopy by angular spectrum digital holography. Three-Dimensional and Multidimensional Microscopy: Image Acquisition and Processing XIII, SPIE.","DOI":"10.1117\/12.645412"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"94","DOI":"10.3389\/fphy.2019.00094","article-title":"Multiwavelength digital holographic imaging and phase unwrapping of protozoa in amplitude and phase using custom Fiji plug-ins","volume":"7","author":"Cohoe","year":"2019","journal-title":"Front. Phys."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"4300","DOI":"10.1364\/OE.14.004300","article-title":"Total aberrations compensation in digital holographic microscopy with a reference conjugated hologram","volume":"14","author":"Colomb","year":"2006","journal-title":"Opt. Express"},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"676","DOI":"10.1038\/nmeth.2019","article-title":"Fiji: An open-source platform for biological-image analysis","volume":"9","author":"Schindelin","year":"2012","journal-title":"Nat. Methods"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"A11","DOI":"10.1364\/JOSAA.404004","article-title":"Using the Gouy phase anomaly to localize and track bacteria in digital holographic microscopy 4D images","volume":"38","author":"Gibson","year":"2021","journal-title":"J. Opt. Soc. Am. Opt. Image Sci. Vis."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"16764","DOI":"10.1364\/OE.394231","article-title":"Enhancing final image contrast in off-axis digital holography using residual fringes","volume":"28","author":"Bedrossian","year":"2020","journal-title":"Opt. Express"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"2419","DOI":"10.1007\/s11051-014-2419-x","article-title":"Dark field nanoparticle tracking analysis for size characterization of plasmonic and non-plasmonic particles","volume":"16","author":"Wagner","year":"2014","journal-title":"J. Nanopart. Res."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"065605","DOI":"10.1088\/0957-0233\/23\/6\/065605","article-title":"Improved nano-particle tracking analysis","volume":"23","author":"Walker","year":"2012","journal-title":"Meas. Sci. Technol."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"073043","DOI":"10.1088\/1367-2630\/ab2f52","article-title":"Single-trajectory spectral analysis of scaled Brownian motion","volume":"21","author":"Sposini","year":"2019","journal-title":"New J. Phys."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"16","DOI":"10.1140\/epje\/i2011-11016-9","article-title":"Probing passive diffusion of flagellated and deflagellated Escherichia coli","volume":"34","author":"Tavaddod","year":"2011","journal-title":"Eur Phys. J. 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