{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/115859"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/115859","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Multilamellar lipid structures and their elastic properties in living systems","abstract":"Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-08-01","abstract_html":"Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-08-01","abstract_has_math":false,"creators":["Bandara, Sarith R."],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Materials Science & Engr","degree_department":null,"school":null,"contributors":["Leal, Cecília","Espinosa-Marzal, Rosa","Evans, Christopher","Harley, Brendan","Kilian, Kristopher"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-08","date_published":"2022-08","updated_at":"2026-07-22T22:24:55Z","subjects":["liposomes","LNPs","extracellular vesicles","EVs","extracellular matrix","ECM","hydrogels","osmotic force","lipid droplets","LDs","multilamellar lipid systems","small-angle X-ray scattering","SAXS","laser scanning confocal microscopy","LSCM","polarized optical microscopy","micropipette aspiration","obesity"],"languages":["en","eng"],"rights":["Copyright 2022 Sarith R. Bandara"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2142/115859","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Leal, Cecília","Espinosa-Marzal, Rosa","Evans, Christopher","Harley, Brendan","Kilian, Kristopher"]},{"key":"dc:creator","label":"Author","values":["Bandara, Sarith R."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2022-08","2022-06-06"]},{"key":"dc:type","label":"Dc Type","values":["text","Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Materials Science & Engr"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["liposomes","LNPs","extracellular vesicles","EVs","extracellular matrix","ECM","hydrogels","osmotic force","lipid droplets","LDs","multilamellar lipid systems","small-angle X-ray scattering","SAXS","laser scanning confocal microscopy","LSCM","polarized optical microscopy","micropipette aspiration","obesity"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en","eng"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2022 Sarith R. Bandara"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2142/115859"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-08-01","The student, Sarith Bandara, accepted the attached license on 2022-05-18 at 18:06.","The student, Sarith Bandara, submitted this Dissertation for approval on 2022-05-18 at 18:37.","This Dissertation was approved for publication on 2022-06-06 at 13:35.","DSpace SAF Submission Ingestion Package generated from Vireo submission #18036 on 2022-11-16 at 10:16:04","Lipids—amphiphilic or hydrophobic molecules directly involved in compartmentalization, metabolism, and transport—are essential for life. Amphiphilic lipids, particularly phospholipids, are the key component of cell membranes and other vesicular entities such as endosomes and extracellular vesicles (EVs), which are involved in the trafficking of useful molecules from one location in the body to another. Not only are they effective at transport, but they are also non-toxic, which has led to their increased prevalence in nanomedicine as drug delivery vehicles. Hydrophobic lipids, particularly glycerolipids and sterol lipids, are the main form in which excess nutrients are stored in the body as lipid droplets (LDs). Evidently, their study has a direct bearing on obesity, a leading cause of death worldwide. While the single lipid bilayer has been thoroughly studied and characterized, studies on multilamellar lipid systems—which are also found extensively in nature—are scarce. This thesis investigates how entities in the body composed of these two amphiphilic and hydrophobic lipid divisions evolve into multilamellar structures under different conditions. For vesicles made of self-assembled amphiphilic lipids, there is a gap in the knowledge of how their structures are affected in the extracellular matrix (ECM). We modeled EVs and lipid-based nanoparticles using liposomes and investigated—using small-angle X-ray scattering (SAXS), laser scanning confocal microscopy (LSCM), and cryogenic transmission electron microscopy—how their structure was affected in an ECM environment, with both pseudo-ECM modeled using synthetic hydrogels and actual ECM. We showed that nanometer-sized liposomes transformed into micrometer-sized aggregates in a hydrogel environment. These aggregates comprised multilamellar vesicles with a mean interlamellar spacing of 5.5 nm. Shielding the liposomes with a corona of poly(ethylene glycol) protected the liposomes from the restructuring effect. We conjectured that the hydrogel environment osmotically drove the unilamellar to multilamellar phase transition. These findings could have major implications in the design of nanomedicines and in understanding the fate and function of EVs within the tissue microenvironment. While cellular LDs composed of hydrophobic lipids are known to increase in size and number under caloric excess, how their structures are affected by obesogenic diets has not been well studied. Understanding LD structure as a function of diet could lead to better therapies that combat obesity. Using SAXS, LSCM, and polarized optical microscopy, we compared the structure of LDs isolated from mice fed diets high in fat and sugar to those isolated from mice fed regular diets. We discovered that LDs have a disordered liquid core and an ordered multilamellar shell, with the multilamellar shell displaying more lamellae for high-calorie diets. We also studied diet-based structural changes of adipocytes and adipose tissue that the LDs were derived from. A natural extension to the study of diet-dependence on the structure of LDs and adipose tissue was the investigation of how their mechanical properties were affected upon caloric excess. While studies on mechanical properties of the endoplasmic reticulum—where LDs are created in the cell—are numerous, mechanical properties of LDs have been virtually unexplored. Using micropipette aspiration, we discovered that the membranes of LDs derived from high-calorie diets demonstrated higher area expansivity moduli (or greater resistance to stretching) compared to those of LDs derived from regular diets. Using atomic force microscopy, we also uncovered that adipose tissue followed a similar trend in Young's moduli, with the tissue from high-calorie diets being stiffer than that from regular diets. These findings could explain why LDs from obese sources, which have greater crystallinity in their outer shell and are more mechanically robust, are harder to metabolize."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Multilamellar lipid structures and their elastic properties in living systems"]}]}],"canonical_facts":{"dc:contributor":["Leal, Cecília","Espinosa-Marzal, Rosa","Evans, Christopher","Harley, Brendan","Kilian, Kristopher"],"dc:creator":["Bandara, Sarith R."],"dc:date":["2022-08","2022-06-06"],"dc:description":["Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2024-08-01","The student, Sarith Bandara, accepted the attached license on 2022-05-18 at 18:06.","The student, Sarith Bandara, submitted this Dissertation for approval on 2022-05-18 at 18:37.","This Dissertation was approved for publication on 2022-06-06 at 13:35.","DSpace SAF Submission Ingestion Package generated from Vireo submission #18036 on 2022-11-16 at 10:16:04","Lipids—amphiphilic or hydrophobic molecules directly involved in compartmentalization, metabolism, and transport—are essential for life. Amphiphilic lipids, particularly phospholipids, are the key component of cell membranes and other vesicular entities such as endosomes and extracellular vesicles (EVs), which are involved in the trafficking of useful molecules from one location in the body to another. Not only are they effective at transport, but they are also non-toxic, which has led to their increased prevalence in nanomedicine as drug delivery vehicles. Hydrophobic lipids, particularly glycerolipids and sterol lipids, are the main form in which excess nutrients are stored in the body as lipid droplets (LDs). Evidently, their study has a direct bearing on obesity, a leading cause of death worldwide. While the single lipid bilayer has been thoroughly studied and characterized, studies on multilamellar lipid systems—which are also found extensively in nature—are scarce. This thesis investigates how entities in the body composed of these two amphiphilic and hydrophobic lipid divisions evolve into multilamellar structures under different conditions. For vesicles made of self-assembled amphiphilic lipids, there is a gap in the knowledge of how their structures are affected in the extracellular matrix (ECM). We modeled EVs and lipid-based nanoparticles using liposomes and investigated—using small-angle X-ray scattering (SAXS), laser scanning confocal microscopy (LSCM), and cryogenic transmission electron microscopy—how their structure was affected in an ECM environment, with both pseudo-ECM modeled using synthetic hydrogels and actual ECM. We showed that nanometer-sized liposomes transformed into micrometer-sized aggregates in a hydrogel environment. These aggregates comprised multilamellar vesicles with a mean interlamellar spacing of 5.5 nm. Shielding the liposomes with a corona of poly(ethylene glycol) protected the liposomes from the restructuring effect. We conjectured that the hydrogel environment osmotically drove the unilamellar to multilamellar phase transition. These findings could have major implications in the design of nanomedicines and in understanding the fate and function of EVs within the tissue microenvironment. While cellular LDs composed of hydrophobic lipids are known to increase in size and number under caloric excess, how their structures are affected by obesogenic diets has not been well studied. Understanding LD structure as a function of diet could lead to better therapies that combat obesity. Using SAXS, LSCM, and polarized optical microscopy, we compared the structure of LDs isolated from mice fed diets high in fat and sugar to those isolated from mice fed regular diets. We discovered that LDs have a disordered liquid core and an ordered multilamellar shell, with the multilamellar shell displaying more lamellae for high-calorie diets. We also studied diet-based structural changes of adipocytes and adipose tissue that the LDs were derived from. A natural extension to the study of diet-dependence on the structure of LDs and adipose tissue was the investigation of how their mechanical properties were affected upon caloric excess. While studies on mechanical properties of the endoplasmic reticulum—where LDs are created in the cell—are numerous, mechanical properties of LDs have been virtually unexplored. Using micropipette aspiration, we discovered that the membranes of LDs derived from high-calorie diets demonstrated higher area expansivity moduli (or greater resistance to stretching) compared to those of LDs derived from regular diets. Using atomic force microscopy, we also uncovered that adipose tissue followed a similar trend in Young's moduli, with the tissue from high-calorie diets being stiffer than that from regular diets. These findings could explain why LDs from obese sources, which have greater crystallinity in their outer shell and are more mechanically robust, are harder to metabolize."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2142/115859"],"dc:language":["en","eng"],"dc:rights":["Copyright 2022 Sarith R. Bandara"],"dc:subject":["liposomes","LNPs","extracellular vesicles","EVs","extracellular matrix","ECM","hydrogels","osmotic force","lipid droplets","LDs","multilamellar lipid systems","small-angle X-ray scattering","SAXS","laser scanning confocal microscopy","LSCM","polarized optical microscopy","micropipette aspiration","obesity"],"dc:title":["Multilamellar lipid structures and their elastic properties in living systems"],"dc:type":["text","Thesis"],"thesis:degree_discipline":["Materials Science & Engr"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:24:55Z"}