Master Thesis

Title: Optimization of the Nano Cellulose production using homogenisation
The use of environmentally friendly, renewable, and sustainable biomaterials is becoming increasingly important. This area of research has attracted the interest of academy and industry because such materials are one solution to resource depletion, environmental pollution, global warming, and the energy crisis. Moreover, biopolymers are essential in biomedicine and nutrition. In this context, so called nanocelluloses and other nano bio polymers (chitin/chitosan, polyesters) are considered promising. Those are isolated as nano-particles, very thin fibres, or crystals from ubiquitous renewable biopolymer sources; example cellulosic sources (e.g., wood, algae, bacteria (also polyesters), tunicates).

These materials can be sourced from conventional agriculture and forestry, but more importantly, can be obtained through industrial biotechnology in the future. They are biodegradable and combine stiffness with high strength, low thermal expansion, low density, high dimensional stability, and can be modified during and after biosynthesis or processing.

Due to these properties, nano-fibrillated celluloses (NFC) or nano crystalline celluloses (NCC) and other nano- biopolymers are expected to appear in various markets soon. These include paper, pulp and packaging, composites, sound and thermal insulation, batteries and fuel cells, sensors, tissue regeneration, 3D printing, drug delivery, cosmetics, and food.

NFC and NCC can be produced in larger quantities from biogenic fibres (using a high-pressure techniques known as fluidizing or homogenizing processes as a core technology.  Pre- and post-treatment equipment for nano-fibre production is necessary as listed above and consist of feedstock, pre-processing, core-processing, characterization/analytics.

In this Master Thesis:

  • different pre-treatment processes (chemical, enzymatic)
  • different conditions parameter using Homogenisation technique (time, pressure, concentration…)

will be studied in order to optimize the production process of the tuned NFC and NCC, which will be produced first time at IBioSys labs using new Homogenizator installed in our labs recently. https://www.tugraz.at/institute/ibiosys/equipment/ibiosys-lab.

Contact person:

Prof. Dr. Karin Stana Kleinschek

Institute for chemistry and technology of biobased systems

Contact email:

karin.stanakleinschek@tugraz.at

Bachelor thesis

Title: Enzyme crosslinked polysaccharide hydrogels

Short description: In view of the demand for environmentally friendly and safe biomaterials for tissue engineering, hydrogels made of natural polymers (e.g. nanocellulose) have become a desirable candidate for the construction of scaffolds for 3D printing applications.

This study will investigate the dual enzyme crosslinking of alginate tyramine utilizing glucose oxidase (GOx) and horseradish peroxidase (HRP) to develop novel hydrogels with enhanced properties. Alginate, a biopolymer known for its biocompatibility and gel-forming capabilities, will be conjugated with tyramine. The crosslinking process will be initiated through a two-enzyme system, such as GOx and HRP. This dual enzyme system offers a controlled and efficient method for hydrogel formation under mild conditions, representing a green chemistry approach. The resultant hydrogels are expected to show an improved mechanical strength, stability, and biodegradability. Their physicochemical properties, including water retention and swelling behavior, will be systematically characterized. The potential biomedical applications of these hydrogels can be realized in tissue engineering.

Key tasks:

  • Conjugate alginate with tyramine to introduce phenolic groups.
  • Catalyze the oxidation of glucose with GOx to generate hydrogen peroxide.
  • Utilize HRP to mediate the crosslinking of phenolic groups on alginate tyramine using hydrogen peroxide.
  • Form a robust hydrogel network through dual enzyme crosslinking.
  • Characterize the physicochemical properties of the hydrogels, including water retention and swelling behavior.

 

Contact person:

Prof. Dr. Karin Stana Kleinschek

Institute for chemistry and technology of biobased systems

Contact email:

karin.stanakleinschek@tugraz.at

tamilselvan.mohan@tugraz.at

Bachelor thesis

Title: Tempo modification of nanocellulose and enzyme assisted crosslinking

Short description: In view of the demand for environmentally friendly and safe biomaterials for tissue engineering, hydrogels made of natural polymers (e.g. nanocellulose) have become a desirable candidate for the construction of scaffolds for 3D printing applications.

This study will explore the synergistic modification of nanocellulose through 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) mediated oxidation and subsequent tyramine functionalization, followed by crosslinking with horseradish peroxidase (HRP). TEMPO oxidation will selectively carboxyl groups on nanocellulose, enhancing its reactivity and functional versatility. The introduction of tyramine to the oxidized nanocellulose will create reactive sites for enzymatic crosslinking. Utilizing HRP in the presence of hydrogen peroxide, we will achieve efficient crosslinking of tyramine-modified nanocellulose, forming a robust hydrogel network. This bio-catalytic process offers a green chemistry approach to producing biocompatible, mechanically resilient nanocellulose-based materials. The resultant hydrogels will exhibit improved mechanical properties, water retention, and biodegradability, presenting significant potential for biomedical applications, including tissue engineering and drug delivery systems.

Key tasks:

  • TEMPO oxidation to selectively carboxylate groups on nanocellulose.
  • Conjugation of tyramine to oxidized nanocellulose to create reactive sites for enzymatic crosslinking.
  • Utilize horseradish peroxidase (HRP) in the presence of hydrogen peroxide for efficient crosslinking of tyramine-modified nanocellulose.
  • Form a robust hydrogel network through HRP-mediated crosslinking.

 

Contact person:

Prof. Dr. Karin Stana Kleinschek

Institute for chemistry and technology of biobased systems

Contact email:

karin.stanakleinschek@tugraz.at

tamilselvan.mohan@tugraz.at