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Sefiane K, Duursma G, Arif A. Patterns from dried drops as a characterisation and healthcare diagnosis technique, potential and challenges: A review. Adv Colloid Interface Sci 2021; 298:102546. [PMID: 34717206 DOI: 10.1016/j.cis.2021.102546] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 10/06/2021] [Accepted: 10/08/2021] [Indexed: 10/20/2022]
Abstract
When particulate-laden droplets evaporate, they leave behind complex patterns on the substrate depending on their composition and the dynamics of their evaporation. Over the past two decades, there has been an increased interest in interpreting these patterns due to their numerous applications in biomedicine, forensics, food quality analysis and inkjet printing. The objective of this review is to investigate the use of patterns from dried drops as a characterisation and diagnosis technique. The patterns left behind by dried drops of various complex fluids are categorised. The potential applications of these patterns are presented, focussing primarily on healthcare, where the future impact could be greatest. A discussion on the limitations which must be overcome and prospective works that may be carried out to allow for widespread implementation of this technique is presented in conclusion.
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Abstract
PURPOSE Morphological features of tear microdesiccates on glass surfaces have been associated with tear fluid status. Tear-film lipids play a critical role in the pathophysiology of some ocular surface disorders. Tear microdesiccates display 4 distinctive morphological domains (zones I, II, III, and transition band). In this study, we investigated the lipid location in tear microdesiccates. METHODS Tear from individual healthy eyes (assessed by symptoms, signs, and slit-lamp examination) was collected using absorbing minisponges. One-µL aliquots were allowed to dry under ambient conditions on microscope slides. Tear microdesiccates were examined by various transmitted light microscopy methods. Tear lipids were located both by partition experiments using 2 lipophilic dyes (Oil red O and Nile blue A) mixed with tear fluid under conditions preserving morphological features of microdesiccates and by assessing the effect of 2 solvents markedly differing in polarity (water and ethanol) on the morphology of particular domains of preformed microdesiccates. RESULTS During desiccation, both Nile blue A and Oil red O became preferentially located in the outermost domain of tear microdesiccates (zone I) without affecting the formation of major fern-like crystalloids (zones II and III). Low volumes of water drastically affected fern-like crystalloids, whereas the gross morphology of zone I was maintained. Contrarily, ethanol, a less polar solvent, was a fixative for fern-like crystalloids, although it markedly affected the bulk of zone I by extracting liquid droplets out of microdesiccates and visibilizing some filamentous subcomponents. CONCLUSIONS Zone I is a hydrophobic domain, whereas zones II and III are highly hydrophilic domains of tear microdesiccates. Zone I represents a lipid-rich structure.
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Traipe-Salas F, Traipe-Castro L, Salinas-Toro D, López D, Valenzuela F, Cartes C, Toledo-Araya H, Pérez C, López Solís R. Progress in tear microdesiccate analysis by combining various transmitted-light microscope techniques. Biol Res 2016; 49:28. [PMID: 27255980 PMCID: PMC4891913 DOI: 10.1186/s40659-016-0089-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 05/24/2016] [Indexed: 11/21/2022] Open
Abstract
Background Tear desiccation on a glass surface followed by transmitted-light microscopy has served as diagnostic test for dry eye. Four distinctive morphological domains (zones I, II, III and transition band) have been recently recognized in tear microdesiccates. Physicochemical dissimilarities among those domains hamper comprehensive microscopic examination of tear microdesiccates. Optimal observation conditions of entire tear microdesiccates are now investigated. One-μl aliquots of tear collected from individual healthy eyes were dried at ambient conditions on microscope slides. Tear microdesiccates were examined by combining low-magnification objective lenses with transmitted-light microscopy (brightfield, phase contrasts Ph1,2,3 and darkfield). Results Fern-like structures (zones II and III) were visible with all illumination methods excepting brightfield. Zone I was the microdesiccate domain displaying the most noticeable illumination-dependent variations, namely transparent band delimited by an outer rim (Ph1, Ph2), homogeneous compactly built structure (brightfield) or invisible domain (darkfield, Ph3). Intermediate positions of the condenser (BF/Ph1, Ph1/Ph2) showed a structured roughly cylindrical zone I. The transition band also varied from invisibility (brightfield) to a well-defined domain comprising interwoven filamentous elements (phase contrasts, darkfield). Conclusions Imaging of entire tear microdesiccates by transmitted-light microscopy depends upon illumination. A more comprehensive description of tear microdesiccates can be achieved by combining illumination methods.
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Affiliation(s)
- Felipe Traipe-Salas
- Cellular and Molecular Biology Program, Faculty of Medicine-ICBM, University of Chile, Independencia 1027, Independencia, Postal code 8380453, Santiago, Chile
| | - Leonidas Traipe-Castro
- Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile
| | - Daniela Salinas-Toro
- Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile
| | - Daniela López
- Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile
| | - Felipe Valenzuela
- Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile
| | - Christian Cartes
- Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile
| | - Héctor Toledo-Araya
- Cellular and Molecular Biology Program, Faculty of Medicine-ICBM, University of Chile, Independencia 1027, Independencia, Postal code 8380453, Santiago, Chile
| | - Claudio Pérez
- Fundación Oftalmológica Los Andes Ophthalmology Clinic (FOLA), Las Hualtatas 5951, Vitacura, Postal code 7650710, Santiago, Chile
| | - Remigio López Solís
- Cellular and Molecular Biology Program, Faculty of Medicine-ICBM, University of Chile, Independencia 1027, Independencia, Postal code 8380453, Santiago, Chile.
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