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Plant cell-inspiredmicrocontainers: Fabrication, Characterization and Applications
KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Fibre- and Polymer Technology, Polymeric Materials.ORCID iD: 0000-0001-5098-3525
2019 (English)Doctoral thesis, comprehensive summary (Other academic) [Artistic work]
Abstract [en]

Biomimetic materials have been inspiring mankind since a longtime for applications in a variety of fields. In particular, the production of lipidbasedvesicles have aided in our understanding of a variety of functions in animalcells, and also served as e.g. drug delivery systems and bioreactors. On thecontrary, the preparation of synthetic plant cells is limited, which is mainly due tothe challenges of building the complex plant primary cell wall fencing the lipidplasma membrane in real plant cells.The present thesis focuses on the bottom-up fabrication ofbiomimetic microcontainers that can serve as simple model systems for plant cells.In the first part, the interactions of plant cell wall polysaccharides, cellulosenanofibers (CNFs), pectin and xyloglucan, are examined. The knowledge is used inthe fabrication of microcapsules and the permeability properties were assessed.The results show that the polysaccharides must be assembled in a specific order inthe capsule wall to incorporate all the three polysaccharides. Additionally, thestructural stability and permeability highly depend on the capsule wallcomposition. The permeability also depends on the composition of thesurrounding media.The second part deals with the fabrication of more advancedbiomimetic microcapsules, with a lipid layer beneath the polysaccharide capsulewall. These capsules are semi-permeable and the phase behavior of the lipids isexploited to grow tubular structures (long filamentous structures) through thecapsule wall, as well as create a vesicle-crowded interior. Real plant cells usetubular structure (Plasmodesmata) for intercellular communications.In the third part, application-oriented aspects of the fabricatedmicrocapsules are discussed. The LbL-derived microcapsules (from the first part)were loaded with active glucose oxidase enzyme, thereby allowing their use as aglucose sensor. The capsule wall acts like a sieve, only allowing small molecules toeffectively pass through. Finally, cell culture experiments demonstrate theirbiocompatibility, paving way for tissue culture applications.

Abstract [sv]

Biomimetiska material har inspirerat mänskligheten sedan längeför applikationer inom olika områden. Framställningen av lipidbaserade vesiklarhar särskilt bidragit till vår förståelse av olika funktioner i djurceller samt tjänatsom t.ex. läkemedelsleveranssystem och bioreaktorer. Tvärtom är beredningen avsyntetiska växtceller begränsad, vilket främst beror på utmaningarna med attbygga och kombinera den komplexa primära cellvägg en med ett lipid-baseratplasmamembran.Denna avhandling fokuserar på ”bottom-up” tillverkning avbiomimetiska mikrobehållare som kan fungera som enkla modellsystem förväxtceller. I den första delen undersöks växelverkningarna mellanväxtcellväggspolysackariderna, cellulosa-nanofibrer (CNF), pektin och xyloglucan.Kunskapen används i nästa steg vid tillverkning av mikrokapslar. Resultaten visaratt, om man vill införliva alla tre polysackarider, måste de adsorberas i en specifikordning. Dessutom beror den strukturella stabiliteten och permeabiliteten hoskapselväggen på kapselväggkompositionen. Permeabiliteten beror också påsammansättningen hos den omgivande vätskan.Den andra delen behandlar tillverkning av mer avanceradebiomimetiska mikrokapslar, som innehåller ett lipidskikt underpolysackaridkapselväggen. Dessa kapslar är permeabla för vissa storlekar avmolekyler men inte andra. Lipidernas fasbeteende utnyttjas för att växa tubulärastrukturer (långa trådformade strukturer) genom kapselväggen, samt för att skapaen inre kapselmiljö som består av många små vesiklar. Växtceller i naturenanvänder rörformade strukturer (så kallade plasmodesmata) för att transporteramolekyler mellan närliggande celler.I den tredje delen diskuteras applikationsorienterade aspekter.Mikrokapslarna, som tillverkat med LbL-tekniken (från den första delen), kanladdas med ett glukosoxidas-enzym, varigenom de går att använda somglukossensor. Permeabilitetsegenskaperna hos kapselväggen tillåter bara att småmolekyler att passerar snabbt. Slutligen visar cellkultursexperiment att kapslarnaär biokompatibla, vilket banar väg för nya biomedicinska applikationer.

Place, publisher, year, edition, pages
Stockholm, Sweden: KTH Royal Institute of Technology, 2019. , p. 66
Series
TRITA-CBH-FOU ; 52
National Category
Natural Sciences Plant Biotechnology Materials Engineering
Identifiers
URN: urn:nbn:se:kth:diva-261587ISBN: 978-91-7873-328-6 (print)OAI: oai:DiVA.org:kth-261587DiVA, id: diva2:1358652
Public defence
2019-11-04, F3, Lindstedtsvägen 26, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

QC 2019-10-08

Available from: 2019-10-08 Created: 2019-10-08 Last updated: 2019-10-08Bibliographically approved
List of papers
1. Bioinspired Layer-by-Layer Microcapsules Based on Cellulose Nanofibers with Switchable Permeability
Open this publication in new window or tab >>Bioinspired Layer-by-Layer Microcapsules Based on Cellulose Nanofibers with Switchable Permeability
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2017 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 18, no 4, p. 1401-1410Article in journal (Refereed) Published
Abstract [en]

Green, all-polysaccharide based microcapsules with mechanically robust capsule walls and fast, stimuli-triggered, and switchable permeability behavior show great promise in applications based on selective and timed permeability. Taking a cue from nature, the build-up and composition of plant primary cell walls inspired the capsule wall assembly, because the primary cell walls in plants exhibit high mechanical properties despite being in a highly hydrated state, primarily owing to cellulose microfibrils. The micro capsules (16 +/- 4 mu m in diameter) were fabricated using the layer-by-layer technique on sacrificial CaCO3 templates, using plant polysaccharides (pectin, cellulose nanofibers, and xyloglucan) only. In water, the capsule wall was permeable to labeled dextrans with a hydrodynamic diameter of similar to 6.6 nm. Upon exposure to NaC1, the porosity of the capsule wall quickly changed allowing larger molecules (similar to 12 nm) to permeate. However, the porosity could be restored to its original state by removal of NaCl, by which permeants became trapped inside the capsule's core. The high integrity of cell wall was due to the CNF and the ON/OFF alteration of the permeability properties, and subsequent loading/unloading of molecules, could be repeated several times with the same capsule demonstrating a robust microcontainer with controllable permeability properties.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2017
National Category
Paper, Pulp and Fiber Technology
Identifiers
urn:nbn:se:kth:diva-207697 (URN)10.1021/acs.biomac.7b00126 (DOI)000399061100036 ()28323423 (PubMedID)2-s2.0-85017647489 (Scopus ID)
Note

QC 20170531

Available from: 2017-05-31 Created: 2017-05-31 Last updated: 2019-10-08Bibliographically approved
2. Bioinspired capsules based on nanocellulose, xyloglucan and pectin - The influence of capsule wall composition on permeability properties
Open this publication in new window or tab >>Bioinspired capsules based on nanocellulose, xyloglucan and pectin - The influence of capsule wall composition on permeability properties
2018 (English)In: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 69, p. 196-205Article in journal (Refereed) Published
Abstract [en]

Materials based on renewable biopolymers, selective permeability and stimuli-responsive release/loading properties play an important role in biomedical applications. Here, in order to mimic the plant primary cell-wall, microcapsules have been fabricated using cell wall polysaccharides, namely pectin, xyloglucan and cellulose nanofibers. For the first time, a large amount of xyloglucan was successfully included in such capsules. These capsules demonstrated stimuli-responsive (ON/OFF) permeability and biocompatibility. The live cell staining revealed that the microcapsules' surface enhanced cell growth and also the non-toxic nature of the microcapsules. In water, the microcapsules were completely and partially permeable to fluorescent dextrans with an average molecular weight of 70 kDa (hydrodynamic diameter of ca. 12 nm) and 2000 kDa (ca. 54 nm), respectively. On the other hand, the permeability dropped quickly when the capsules were exposed to 250 mM NaCl solution, trapping a fraction of the 70 kDa dextrans in the capsule interior. The decrease in permeability was a direct consequence of the capsule-wall composition, i.e. the presence of xyloglucan and a low amount of charged molecules such as pectin. The low permeability of capsules in saline conditions (and in a model biological medium), combined with a capsule wall that is made from dietary fibers only, potentially enables their use in biological applications, such as colon targeted delivery in the gastro-intestinal tract. 

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2018
Keywords
Biomimetic microcapsules, Cellulose nanofiber, Xyloglucan, Pectin, Switchable permeability, Layer-by-layer
National Category
Materials Engineering
Identifiers
urn:nbn:se:kth:diva-225719 (URN)10.1016/j.actbio.2018.01.003 (DOI)000427334100015 ()29341931 (PubMedID)
Funder
Swedish Foundation for Strategic Research , ICA14-0045
Note

QC 20180410

Available from: 2018-04-10 Created: 2018-04-10 Last updated: 2019-10-11Bibliographically approved
3. Assembly of Primary Cell-Wall inspired Microcontainers, Plantosomes, as a step towards a Synthetic Plant-Cell
Open this publication in new window or tab >>Assembly of Primary Cell-Wall inspired Microcontainers, Plantosomes, as a step towards a Synthetic Plant-Cell
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(English)Manuscript (preprint) (Other academic) [Artistic work]
National Category
Agricultural and Veterinary sciences Natural Sciences
Identifiers
urn:nbn:se:kth:diva-261398 (URN)
Note

QC 20191011

Available from: 2019-10-06 Created: 2019-10-06 Last updated: 2019-10-11Bibliographically approved
4. Porous Cellulose Nanofiber-Based Microcapsules for Biomolecular Sensing
Open this publication in new window or tab >>Porous Cellulose Nanofiber-Based Microcapsules for Biomolecular Sensing
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2018 (English)In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, no 48, p. 41146-41154Article in journal (Refereed) Published
Abstract [en]

Cellulose nanofibers (CNFs) have recently attracted a lot of attention in sensing because of their multifunctional character and properties such as renewability, nontoxicity, biodegradability, printability, and optical transparency in addition to unique physicochemical, barrier, and mechanical properties. However, the focus has exclusively been devoted toward developing two-dimensional sensing platforms in the form of nanopaper or nanocellulose-based hydrogels. To improve the flexibility and sensing performance in situ, for example, to detect biomarkers in vivo for early disease diagnostics, more advanced CNF-based structures are needed. Here, we developed porous and hollow, yet robust, CNF-based microcapsules using only the primary plant cell wall components, CNF, pectin, and xyloglucan, to assemble the capsule wall. The fluorescein isothiocyanate-labeled dextrans with M-w of 70 and 2000 kDa could enter the hollow capsules at a rate of 0.13 +/- 0.04 and 0.014 +/- 0.009 s(-1), respectively. This property is very attractive because it minimizes the influence of mass transport through the capsule wall on the response time. As a proof of concept, glucose oxidase (GOx) enzyme was loaded (and cross-linked) in the microcapsule interior with an encapsulation efficiency of 68 +/- 2%. The GOx-loaded microcapsules were immobilized on a variety of surfaces (here, inside a flow channel, on a carbon-coated sensor or a graphite rod) and glucose concentrations up to 10 mM could successfully be measured. The present concept offers new opportunities in the development of simple, more efficient, and disposable nanocellulose-based analytical devices for several sensing applications including environmental monitoring, healthcare, and diagnostics.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
cellulose nanofibers, microcapsules, glucose oxidase, sensing, sensor, layer-by-layer
National Category
Polymer Technologies
Identifiers
urn:nbn:se:kth:diva-240733 (URN)10.1021/acsami.8b16058 (DOI)000452694100022 ()30412378 (PubMedID)2-s2.0-85057799223 (Scopus ID)
Funder
Swedish Foundation for Strategic Research , ICA14-0045Swedish Research Council, VR-2017-4887Science for Life Laboratory - a national resource center for high-throughput molecular bioscience
Note

QC 20190109

Available from: 2019-01-09 Created: 2019-01-09 Last updated: 2019-10-08Bibliographically approved

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The full text will be freely available from 2020-10-01 11:00
Available from 2020-10-01 11:00

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Paulraj, Thomas

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7891011121310 of 18
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