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Responsivity analysis of smart nanoparticles using Field-Flow Fractionation
Thesis (MSc) -- Stellenbosch University, 2022.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2022
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| _version_ | 1867613994570743808 |
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| access_status_str | Open Access |
| author | Stanvliet, Zahn |
| author2 | Lederer, Albena |
| author_browse | Lederer, Albena Stanvliet, Zahn |
| author_facet | Lederer, Albena Stanvliet, Zahn |
| author_sort | Stanvliet, Zahn |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MSc) -- Stellenbosch University, 2022. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/126200 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:44:59.428Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2022 |
| publishDateRange | 2022 |
| publishDateSort | 2022 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/126200 Responsivity analysis of smart nanoparticles using Field-Flow Fractionation Stanvliet, Zahn Lederer, Albena Stellenbosch University. Faculty of Science. Dept. of Chemistry and Polymer Science. Field-flow fractionation Nanoparticles Nanostructured materials Drug delivery systems UCTD Thesis (MSc) -- Stellenbosch University, 2022. ENGLISH ABSTRACT: Future research on advanced nanoparticles will be based on well-defined, characterized nanostructured materials. Smart polymersomes, in particular, exhibit a variety of characteristics that are essential for drug delivery systems (DDs). A detailed understanding of self-assembly, responsive behaviour, and the influence of structural features are required to develop smart polymersomes for a given application. This study aimed to better understand the responsiveness of smart polymersomes made from tertiary amine methacrylate-based block copolymers (BCPs) in solution at various temperature and pH conditions and how their composition influences their behavior. Polymersomes based on polyethylene glycol (PEG), poly(diethylaminoethyl methacrylate) (PDEAEMA), poly(dimethylaminoethyl methacrylate) (DMAEMA), and poly(dimethylmaleicimidobutyl methacrylate) (DMIBMA) were investigated by dynamic light scattering (DLS), cryogenic transmission electron microscopy (cryo-TEM) and asymmetric flow field-flow fractionation (AF4). The aforementioned BCPs include permanently hydrophylic blocks with segments that are thermo- and pH-sensitive, hence they possesed dual stimuli responsive character. The responsive block goes through a coil-globule transition when the temperature or pH changes. All BCPs displayed different response behaviours, influenced by the type of comonomer, as well as the amount integrated into the BCP. A phase transition, in this case, is an abrupt change in the BCPs hydrophilicity, when it transitions from a hydrophilic to a hydrophobic state with a change in pH or temperature. By increasing the hydrophobicity of the BCP, the phase transition was pushed to lower pH (at constant temperature) or lower temperatures (at constant pH). The composition of BCPs significantly impacts their temperature sensitivity and solution behaviour. Cross-linked polymersomes exhibited stable reversible swelling. Cross-linked and uncross-linked polymersomes showed no response at elevated temperatures. It was observed for the first time, that uncross-linked polymersomes of PEG PDEA-PDMA-PDMI demonstrated responsiveness at low temperatures between 3 °C and 5 °C. This response is reversible and is suppressed through cross-linking. At low temperatures, the BCP exhibited shape-shifting behaviour. This phenomenon is hypothesized to be caused by surface plasticization of the insoluble structure-directing block, leading to a slight adjustment in the packing parameter, causing a morphological transition. More specifically, the membrane-forming block underwent plasticization triggered by a change in temperature, causing a minute adjustment in the relative degree of hydration of the stimuli-responsive block, effectively raising the hydrophilic block's volume fraction. This behaviour is thought to be caused by the incorporation of DMAEMA units into the stimuli responsive block. AFRIKAANS OPSOMMING: Toekomstige navorsing oor gevorderde nanopartikels sal gebaseer wees op goed gedefinieerde, gekarakteriseerde nano-gestruktureerde materiale. Slim polimersome, veral, vertoon 'n verskeidenheid eienskappe wat noodsaaklik is vir dwelmafleweringstelsels (DD's). 'n Gedetailleerde begrip van selfsamestelling, responsiewe gedrag en die invloed van strukturele kenmerke word vereis om slim polimersome vir 'n gegewe toepassing te ontwikkel. Hierdie studie het ten doel gehad om die responsiwiteit van slim polimersome wat gemaak is van tersiêre amien-metakrilaat-gebaseerde blokkopolimere (BCP's) in oplossing by verskeie temperatuur- en pH-toestande beter te verstaan en hoe hul samestelling hul gedrag beïnvloed. Polimersome gebaseer op poliëtileenglikol (PEG), poli(diëtielamino etielmetakrilaat) (PDEAEMA), poli(dimetielamino-etielmetakrilaat) (DMAEMA), en poli(dimetielmaleicimidobutielmetakrilaat) (DMIBMA) is ondersoek deur dinamiese ligverstrooiing (DLS), kriogene-oordrag-elektron mikroskopie (cryo-TEM) en asimmetriese vloei veldvloei fraksionering (AF4). Die voorgenoemde BCP's sluit permanent hidrofiliese blokke in met segmente wat termo- en pH-sensitief is, dus het hulle 'n dubbele stimuli responsiewe karakter. Die responsiewe blok gaan deur 'n spoel-bol-oorgang wanneer die temperatuur of pH verander. Alle BCP's het verskillende reaksiegedrag getoon, beïnvloed deur die tipe komonomeer, sowel as die hoeveelheid geïntegreer in die BCP. 'n Fase-oorgang, in hierdie geval, is 'n skielike verandering in die BCP se hidrofilisiteit, wanneer dit oorgaan van 'n hidrofiele na 'n hidrofobiese toestand met 'n verandering in pH of temperatuur. Deur die hidrofobisiteit van die BCP te verhoog, is die fase-oorgang na laer pH (by konstante temperatuur) of laer temperature (by konstante pH) gedruk. Die samestelling van BCP's beïnvloed hul temperatuursensitiwiteit en oplossingsgedrag aansienlik. Kruisgebonde polimersome het stabiele omkeerbare swelling getoon. Kruisgebonde en onverbonde polimersome het geen reaksie by verhoogde temperature getoon nie. Daar is vir die eerste keer waargeneem dat ongekruisgekoppelde polimersome van PEG-PDEA-PDMA-PDMI reaksie getoon het by lae temperature tussen 3 °C en 5 °C. Hierdie reaksie is omkeerbaar en word onderdruk deur kruiskoppeling. By lae temperature het die BCP vormverskuiwende gedrag getoon. Hierdie verskynsel word veronderstel om veroorsaak te word deur oppervlakplastisering van die onoplosbare struktuurgerigte blok, wat lei tot 'n effense aanpassing in die pakkingsparameter, wat 'n morfologiese oorgang veroorsaak. Meer spesifiek, die membraanvormende blok het plastisering ondergaan wat veroorsaak is deur 'n verandering in temperatuur, wat 'n minuut aanpassing in die relatiewe graad van hidrasie van die hidrofobiese blok veroorsaak het, wat die hidrofiele blok se volumefraksie effektief verhoog het. Hierdie gedrag word vermoedelik veroorsaak deur die inkorporering van DMAEMA eenhede in die hidrofobiese blok. Die polimersome insluitend die vormverskuifde spesies is met behulp van AF4 gekarakteriseer. AF4 is 'n geskikte tegniek vir die karakterisering van slim polimersome sowel as onbekende nanostrukture. Die magdom inligting wat deur AF4 verkry is, insluitend DLS en cryo-TEM, het 'n dieper begrip van hul eienskappe en responsiwiteit moontlik gemaak. Masters 2022-11-24T11:38:31Z 2023-01-16T12:55:17Z 2022-11-24T11:38:31Z 2023-01-16T12:55:17Z 2021-02 Thesis http://hdl.handle.net/10019.1/126200 en_ZA Stellenbosch University xx, 87 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Field-flow fractionation Nanoparticles Nanostructured materials Drug delivery systems UCTD Stanvliet, Zahn Responsivity analysis of smart nanoparticles using Field-Flow Fractionation |
| title | Responsivity analysis of smart nanoparticles using Field-Flow Fractionation |
| title_full | Responsivity analysis of smart nanoparticles using Field-Flow Fractionation |
| title_fullStr | Responsivity analysis of smart nanoparticles using Field-Flow Fractionation |
| title_full_unstemmed | Responsivity analysis of smart nanoparticles using Field-Flow Fractionation |
| title_short | Responsivity analysis of smart nanoparticles using Field-Flow Fractionation |
| title_sort | responsivity analysis of smart nanoparticles using field flow fractionation |
| topic | Field-flow fractionation Nanoparticles Nanostructured materials Drug delivery systems UCTD |
| url | http://hdl.handle.net/10019.1/126200 |
| work_keys_str_mv | AT stanvlietzahn responsivityanalysisofsmartnanoparticlesusingfieldflowfractionation |