Aqueous two-phase systems for starch microsphere formulation and encapsulation of live bacteria : A phase behaviour perspective
(2024)- Abstract
- The human gastrointestinal tract (GIT) is home to a large community of microorganisms that contribute to human health. Delivering live bacteria to the gut for therapeutic purposes can thus be highly beneficial. However, delivering live biotherapeutic products or probiotic bacteria to the GIT presents challenges because the cells must remain viable during production, storage, and administration. Encapsulating the bacteria in starch microspheres is an interesting approach for this purpose. Starch microspheres can be produced in aqueous two-phase systems (ATPSs). These ATPS can be created by dissolving the starch in water along with polymers of a different chemical nature. Emulsification of the system can generate dispersed starch phase... (More)
- The human gastrointestinal tract (GIT) is home to a large community of microorganisms that contribute to human health. Delivering live bacteria to the gut for therapeutic purposes can thus be highly beneficial. However, delivering live biotherapeutic products or probiotic bacteria to the GIT presents challenges because the cells must remain viable during production, storage, and administration. Encapsulating the bacteria in starch microspheres is an interesting approach for this purpose. Starch microspheres can be produced in aqueous two-phase systems (ATPSs). These ATPS can be created by dissolving the starch in water along with polymers of a different chemical nature. Emulsification of the system can generate dispersed starch phase droplets in a continuous polymer phase. Here, the starch can crystallise into solid microspheres, by utilising the natural crystallisation ability of pre-gelatinised starch. The ATPSs can provide a gentle environment for sensitive compounds, such as biologics. Moreover, the digestion of starch in the GIT could potentially be utilised as an oral delivery mechanism for encapsulated cargo.
Starch microsphere encapsulation can thus be regarded as a promising concept in the fields of food and pharmaceutical formulation, and several investigations have been conducted to better understand starch microsphere preparation in ATPSs. However, there is still limited knowledge regarding the starch microsphere formation and how to control the preparation process. One area that has received little focus is phase behaviour in relation to starch microsphere preparation, despite phase behaviour being a fundamental aspect of ATPS science. Moreover, numerous different polymer combinations can make up ATPSs, but polyethylene glycol (PEG) has generally been used as a continuous phase polymer during ATPS starch microsphere preparation.
Therefore, this thesis aims to derive new knowledge about the preparation and formation of starch microspheres in ATPSs and relate this to the phase behaviour of the systems. Our research explored how different parameters (such as the type and size of polymers in the continuous phase) influence ATPS phase behaviour and starch microsphere formation. This thesis also presents a novel method to monitor the starch particle formation process, imaging the crystallisation of starch phase droplets in-situ. The findings highlight the potential of utilising different continuous phase polymers, as well as the importance of the phase behaviour (such as water distribution in the ATPS, which is essential for starch crystallisation). Moreover, the thesis demonstrates that it is possible to encapsulate live bacteria in starch-based ATPS, offering a promising concept for further development in food and pharmaceutical sciences. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/fe8d61fd-63e4-4750-99c0-76adac232d22
- author
- Gidlöf, Zandra LU
- supervisor
- opponent
-
- Former Associate Professor(retired) Bertoft, Eric, Åbo Academy University, Finland
- organization
- publishing date
- 2024
- type
- Thesis
- publication status
- published
- subject
- keywords
- Starch microspheres, Starch microparticles, Microencapsulation, Aqueous two-phase systems, ATPS, Hydrolysed waxy barley starch, PEG, PVP, PEtOx, Phase behaviour, Water distribution, Water activity, Starch crystallisation, Light microscopy, Confocal Raman microscopy, WAXS, Isothermal calorimetry, SEM, DSC, L. reuteri, Probiotics, Live biotherapeutic products
- pages
- 84 pages
- publisher
- Department of Process and Life Science Engineering, Lund University.
- defense location
- Lecture Hall KC:C, Kemicentrum, Naturvetarvägen 22, Faculty of Engineering LTH, Lund. The dissertation will be live streamed, but part of the premises is to be excluded from the live stream.
- defense date
- 2024-11-22 09:00:00
- ISBN
- 978-91-8096-081-6
- 978-91-8096-080-9
- project
- Aqueous two-phase systems for starch microsphere formulation and encapsulation of live bacteria - A phase behaviour perspective
- language
- English
- LU publication?
- yes
- id
- fe8d61fd-63e4-4750-99c0-76adac232d22
- date added to LUP
- 2024-10-25 17:22:18
- date last changed
- 2025-04-04 13:57:29
@phdthesis{fe8d61fd-63e4-4750-99c0-76adac232d22,
abstract = {{The human gastrointestinal tract (GIT) is home to a large community of microorganisms that contribute to human health. Delivering live bacteria to the gut for therapeutic purposes can thus be highly beneficial. However, delivering live biotherapeutic products or probiotic bacteria to the GIT presents challenges because the cells must remain viable during production, storage, and administration. Encapsulating the bacteria in starch microspheres is an interesting approach for this purpose. Starch microspheres can be produced in aqueous two-phase systems (ATPSs). These ATPS can be created by dissolving the starch in water along with polymers of a different chemical nature. Emulsification of the system can generate dispersed starch phase droplets in a continuous polymer phase. Here, the starch can crystallise into solid microspheres, by utilising the natural crystallisation ability of pre-gelatinised starch. The ATPSs can provide a gentle environment for sensitive compounds, such as biologics. Moreover, the digestion of starch in the GIT could potentially be utilised as an oral delivery mechanism for encapsulated cargo. <br/><br/>Starch microsphere encapsulation can thus be regarded as a promising concept in the fields of food and pharmaceutical formulation, and several investigations have been conducted to better understand starch microsphere preparation in ATPSs. However, there is still limited knowledge regarding the starch microsphere formation and how to control the preparation process. One area that has received little focus is phase behaviour in relation to starch microsphere preparation, despite phase behaviour being a fundamental aspect of ATPS science. Moreover, numerous different polymer combinations can make up ATPSs, but polyethylene glycol (PEG) has generally been used as a continuous phase polymer during ATPS starch microsphere preparation. <br/><br/>Therefore, this thesis aims to derive new knowledge about the preparation and formation of starch microspheres in ATPSs and relate this to the phase behaviour of the systems. Our research explored how different parameters (such as the type and size of polymers in the continuous phase) influence ATPS phase behaviour and starch microsphere formation. This thesis also presents a novel method to monitor the starch particle formation process, imaging the crystallisation of starch phase droplets in-situ. The findings highlight the potential of utilising different continuous phase polymers, as well as the importance of the phase behaviour (such as water distribution in the ATPS, which is essential for starch crystallisation). Moreover, the thesis demonstrates that it is possible to encapsulate live bacteria in starch-based ATPS, offering a promising concept for further development in food and pharmaceutical sciences.}},
author = {{Gidlöf, Zandra}},
isbn = {{978-91-8096-081-6}},
keywords = {{Starch microspheres; Starch microparticles; Microencapsulation; Aqueous two-phase systems; ATPS; Hydrolysed waxy barley starch; PEG; PVP; PEtOx; Phase behaviour; Water distribution; Water activity; Starch crystallisation; Light microscopy; Confocal Raman microscopy; WAXS; Isothermal calorimetry; SEM; DSC; L. reuteri; Probiotics; Live biotherapeutic products}},
language = {{eng}},
publisher = {{Department of Process and Life Science Engineering, Lund University.}},
school = {{Lund University}},
title = {{Aqueous two-phase systems for starch microsphere formulation and encapsulation of live bacteria : A phase behaviour perspective}},
url = {{https://lup.lub.lu.se/search/files/198292945/Avhandling_Zandra_Gidl_f_LUCRIS.pdf}},
year = {{2024}},
}