Rheological insights into Cellulose Nanofibrils: Implications for Biomedical Hydrogels

No Thumbnail Available

Files

URL

Journal Title

Journal ISSN

Volume Title

Kemiantekniikan korkeakoulu | Bachelor's thesis
Electronic archive copy is available locally at the Harald Herlin Learning Centre. The staff of Aalto University has access to the electronic bachelor's theses by logging into Aaltodoc with their personal Aalto user ID. Read more about the availability of the bachelor's theses.
Unless otherwise stated, all rights belong to the author. You may download, display and print this publication for Your own personal use. Commercial use is prohibited.

Authors

Date

2024-05-28

Department

Major/Subject

Kemia ja materiaalitiede

Mcode

CHEM3049

Degree programme

Kemiantekniikan kandidaattiohjelma

Language

en

Pages

28

Series

Abstract

For the past decade, researchers have been exploring the potential of biomaterials in various biomedical applications. One of the most relevant biomaterials is cellulose, being widely available and inexpensive. Cellulose nanofibrils (CNFs) can be extracted from cellulose using chemical and mechanical methods. Cellulose chains, being abundant in hydroxyl groups, enable them to undergo various modifications and, therefore, for multiple applications in medicine, cosmetics, and packaging industry. Researching the suitability of biopolymers in the biomedical field is important because synthetic polymers cannot be utilized due to their potential toxicity and incompatibility. However, consideration is necessary when selecting biomaterials for such applications. They should fulfill the criteria of biocompatibility, non-toxicity, and biodegradability. This thesis focuses on the utilization of cellulose nanofibril hydrogels in biomedical applications. Hydrogels have already been applied to wound healing, cell culturing and controlled drug delivery. The suitability for such applications is considered based on the rheological behavior. Rheology describes the science of flow and deformation, it usually studies the change in shear-thinning properties, such as viscosity and thixotropy. These properties are directly influenced by surface chemistry and concentration of a material. The viscosity of CNF suspensions decreases as the shear rate increases. However, the viscosity increases again, when shear rate is zero, showing that material owns thixotropic behavior. Pure CNF suspensions tend to flocculate, so therefore chemical pretreatments are necessary. Electrostatic repulsion between fibrils with the same charge, due to TEMPO- oxidation, results in improved colloidal stability. TEMPO-CNFs form hydrogels, even at low concentrations. In addition to amazing properties and diverse modification opportunities, CNFs meet plenty of challenges. Cellulose itself is affordable, but TEMPO-oxidation increases the manufacturing costs significantly. Additionally, it lowers the energy consumption of mechanical processes, however, it has a more negative impact on the environment. Lack of mechanical properties causes difficulties, especially in 3D printing. During drying, the scaffolds tend to suffer collapsing. However, combining CNFs with other biomaterials with better properties, is a solution for wider applications opportunities.

Description

Supervisor

Kontturi, Eero

Thesis advisor

Teixeira Polez, Roberta

Keywords

CNF, rheology, biomedical application, hydrogel, TEMPO

Other note

Citation

Permanent link to this item

https://urn.fi/URN:NBN:fi:aalto-202406254950

Collections

[kand] Kemian tekniikan korkeakoulu / CHEM