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Liquid crystalline cubic phase nanoparticles and emulsions stabilized by softwood hemicellulose

Pålsson, David LU (2020) KEML10 20201
Mathematical Statistics
Department of Chemistry
Abstract
Cubosomes are nanoparticles that are prepared by dispersing a liquid crystalline cubic phase. Typically, the cubosomes are stabilized by copolymers to prevent the colloids from aggregating. In this thesis galactoglucomannans (GGM) from softwood was evaluated as a stabilizer for monoolein cubosomes and triolein emulsions.
Galactoglucomannans are the most abundant hemicellulose in softwood and have previously been tested as a stabilizer of emulsions, due to its similarities with commercially used stabiliser such as guar gum. The use of GGM as a stabilizer is a possible new use for materials from biorefineries.
Here, triolein emulsions were prepared with two different GGM samples. The stability of the emulsions over 12 weeks were evaluated... (More)
Cubosomes are nanoparticles that are prepared by dispersing a liquid crystalline cubic phase. Typically, the cubosomes are stabilized by copolymers to prevent the colloids from aggregating. In this thesis galactoglucomannans (GGM) from softwood was evaluated as a stabilizer for monoolein cubosomes and triolein emulsions.
Galactoglucomannans are the most abundant hemicellulose in softwood and have previously been tested as a stabilizer of emulsions, due to its similarities with commercially used stabiliser such as guar gum. The use of GGM as a stabilizer is a possible new use for materials from biorefineries.
Here, triolein emulsions were prepared with two different GGM samples. The stability of the emulsions over 12 weeks were evaluated with DLS measurements. Cubosomes of monoolein stabilized with three different types of GGM was prepared and the obtained cubosomes were examined with SAXS and Cryo-TEM. The stability of the cubosomes were evaluated with zeta potential measurement and a six-week storage tests where the size development was measured by DLS. Ellipsometry was also performed on the cubosomes stabilized with GGM and cubosomes prepared without any stabilizer, and the results were compared. The cubosome stability in phosphate saline buffer over a four-hour period was also evaluated.
The results showed that the emulsions stayed relatively stable over 12 weeks of storage, with some creaming. The SAXS showed that cubosomes with Pn3m structure were formed. The zeta potential and the stability measurements of the cubosomes showed that cubosomes were quite stable. The ellipsometry data and buffer stability measurement were not unambiguous, but from the combined results it was concluded that GGM could be used to stabilize cubosomes. The difference in stabilizing properties between the GGM samples used are discussed. (Less)
Popular Abstract (Swedish)
Kubosomer är nanopartiklar där den inre strukturen är uppbyggd av ett dubbellager av fettmolekyler som omsluter en tredimensionell struktur av vattenkanaler. Denna unika struktur gör att nanopartiklarna kan lastas med hydrofoba, hydrofila och amfifila molekyler. Detta gör dem lovande för bland annat läkemedelsadministration. Kubosomer är i sig själva inte kolloidalt stabila utan aggregerar i en vattenlösning. För att motverka detta tillsätter man stabilisatorer. Dessa är ofta polymerer med en hydrofob och en hydrofil del. Den hydrofoba delen adsorberas på ytan av kubosomerna, medan de hydrofila delarna sticker ut i vattenlösningen. De hydrofila delarna hindrar kubosomerna från att komma för nära varandra och aggregera, vilket kallas... (More)
Kubosomer är nanopartiklar där den inre strukturen är uppbyggd av ett dubbellager av fettmolekyler som omsluter en tredimensionell struktur av vattenkanaler. Denna unika struktur gör att nanopartiklarna kan lastas med hydrofoba, hydrofila och amfifila molekyler. Detta gör dem lovande för bland annat läkemedelsadministration. Kubosomer är i sig själva inte kolloidalt stabila utan aggregerar i en vattenlösning. För att motverka detta tillsätter man stabilisatorer. Dessa är ofta polymerer med en hydrofob och en hydrofil del. Den hydrofoba delen adsorberas på ytan av kubosomerna, medan de hydrofila delarna sticker ut i vattenlösningen. De hydrofila delarna hindrar kubosomerna från att komma för nära varandra och aggregera, vilket kallas steriskt stabilisering.
Hemicellulosa är en grupp av polysackarider som tillsammans med cellulosa och lignin utgör de huvudsakliga komponenterna i trä. Den vanligaste typen av hemicellulosa i barrträd är galactoglucomannan (GGM). Flera polysackarider med liknande struktur som GGM används som stabiliserings- och förtjockningsmedel inom livsmedelsindustrin. Mest känd är troligen gummi arabicum. GGM har använts i ett par studier som stabiliseringsmedel av emulsioner.
I detta arbete undersöktes huruvida GGM kan användas som stabilisator för emulsioner av triolein och vatten och för kubosomer av monoolein. Stabiliteten för emulsionerna och kubosomerna mättes med dynamisk ljusspridning (DLS). Kubosomerna undersöktes därutöver med Small Angle X-ray Scattering (SAXS) och cryogenic Transition Electron Microscopy (Cryo-TEM). Resultatet visade att det går att stabilisera emulsioner och kubosomer med GGM. Kubosomerna var stabila i en vattenlösning i minst sex veckor, medan emulsionerna visade tecken på gräddning och flockuering under de 12 veckor som stabiliteten undersöktes.
Skillnader i stabiliserande förmåga mellan de prover av GGM som användes, samt möjligheten att lignin bundet till GGM förbättrar GGM som stabilisator för kubosomer diskuteras. (Less)
Please use this url to cite or link to this publication:
author
Pålsson, David LU
supervisor
organization
course
KEML10 20201
year
type
M2 - Bachelor Degree
subject
keywords
physical chemistry, cubosomes, emulsions, galactoglucomannans, fysikalisk kemi
language
English
id
9018321
date added to LUP
2020-07-06 10:30:55
date last changed
2020-07-06 10:30:55
@misc{9018321,
  abstract     = {{Cubosomes are nanoparticles that are prepared by dispersing a liquid crystalline cubic phase. Typically, the cubosomes are stabilized by copolymers to prevent the colloids from aggregating. In this thesis galactoglucomannans (GGM) from softwood was evaluated as a stabilizer for monoolein cubosomes and triolein emulsions.
Galactoglucomannans are the most abundant hemicellulose in softwood and have previously been tested as a stabilizer of emulsions, due to its similarities with commercially used stabiliser such as guar gum. The use of GGM as a stabilizer is a possible new use for materials from biorefineries. 
Here, triolein emulsions were prepared with two different GGM samples. The stability of the emulsions over 12 weeks were evaluated with DLS measurements. Cubosomes of monoolein stabilized with three different types of GGM was prepared and the obtained cubosomes were examined with SAXS and Cryo-TEM. The stability of the cubosomes were evaluated with zeta potential measurement and a six-week storage tests where the size development was measured by DLS. Ellipsometry was also performed on the cubosomes stabilized with GGM and cubosomes prepared without any stabilizer, and the results were compared. The cubosome stability in phosphate saline buffer over a four-hour period was also evaluated.
The results showed that the emulsions stayed relatively stable over 12 weeks of storage, with some creaming. The SAXS showed that cubosomes with Pn3m structure were formed. The zeta potential and the stability measurements of the cubosomes showed that cubosomes were quite stable. The ellipsometry data and buffer stability measurement were not unambiguous, but from the combined results it was concluded that GGM could be used to stabilize cubosomes. The difference in stabilizing properties between the GGM samples used are discussed.}},
  author       = {{Pålsson, David}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Liquid crystalline cubic phase nanoparticles and emulsions stabilized by softwood hemicellulose}},
  year         = {{2020}},
}