PHASES

Phase I

Title: Understanding the mechanism through which microalgae growth conditions governs the extracted sEPS’s antibacterial,

morphological, thermal and structural properties

Period: 08.01.2025 – 31.12.2025

Summary of the activity report

Removable orthodontic appliances (ROA) are particularly important in the treatment of dental diseases, but, in addition to this beneficial role, they can create a favorable environment for the proliferation of pathogenic microorganisms and the formation of a biofilm on the surface of the orthodontic appliance. The overall objective of the Waste2Coat project is the conversion of polysaccharide-rich bio-waste from microalgae culture into new durable and functional biomaterials with antibacterial properties and applications in orthodontic engineering. Special attention was paid to understanding the connection between the microalgae growth medium, the inoculum preparation method and the structural and biological characteristics of the final EPS. Thus, during this phase, different autotrophic and/or mixotrophic growth conditions in closed photobioreactors of Porphyridium purpureum were tested. Also, specific microalgae culture media were tested and optimized to obtain high yields of sEPS from microalgae biomass and, following the experiments carried out, Porphyridium purpureum cultivation methodology was established. The extracted EPS were subjected to a complex characterization in order to select the version with the highest thermal stability and content of active sulfur groups. Several types of biomaterials (in the form of films and scaffolds) were produced, all based on mixtures formed of nanocellulose, treated with silane agents or oxidized, and fucoidan and/or genipin in different mass ratios. In order to improve the mechanical resistance of biomaterials in the form of scaffolds, sodium and calcium salts were tested, these being recognized as crosslinking agents for sulfated polysaccharides. The obtained biomaterials were characterized from a morphological, structural, thermal and rheological point of view. Also, some of the obtained biomaterials were subjected to antibacterial evaluation using specific methods. As a result of these works, several protocols were established for obtaining biomaterials that contain sEPS and nanocellulose.

DISSEMINATION

Published papers:     

1.          Panaitescu DM, Vizireanu Sorin, Raduly MF, Sătulu V, Stancu C, Marascu V, Nicolae C-A, Gabor AR, Oprică GM, Uşurelu CD, Caraş I, Frone AN.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) modified with toughening agents and surface treated by atmospheric cold plasma for tissue engineering.

International Journal of Biological Macromolecules, 2025, 333:148780. https://doi.org/10.1016/j.ijbiomac.2025.148780

2.         Panaitescu DM, Vizireanu SI, Oprică GM, Uşurelu CD, Stancu C, Sătulu V, Ghiurea M, Nicolae C-A, Raduly MF, Frone AN. Influence of Cold Plasma Treatment on Cellulose Modification with Different Oxidizing Agents. Materials, 2025, 18(5):1066. https://doi.org/10.3390/ma18051066

Conferences:

1.          Gabriela-Mădălina Oprică, Cătălina-Diana Ușurelu, Cristian-Andi Nicolae, Marinela Victoria Dumitru, Valentin Rădițoiu, Denis-Mihaela Panaitescu, Radu-Claudiu Fierăscu, Adriana-Nicoleta Frone^*, Impact of surface treatments on cellulose nanofibers: a comparative study on their interaction with a sulfated polysaccharide. Applications of Chemistry in Nanosciences and Biomaterials Engineering NanoBioMat 2025 – Winter Edition, 26-28 November, Bucharest, oral presentation, online

2.      Gabriela-Madalina Oprica, Catalina-Diana Usurelu, Adriana-Nicoleta Frone, Cristian-Andi Nicolae, Iulia-Elena Neblea, Valentin Radițoiu, Raluca Augusta Gabor, Radu-Claudiu Fierascu, Denis-Mihaela Panaitescu, Physical-chemical characterization of novel polysaccharide-based gels. 23^rd International Balkan Workshop on Applied Physics and Materials Science IBWAP Constanta, 9-12 July, 2025, poster presentation

3.       Catalina-Diana Usurelu, Gabriela-Madalina Oprica, Denis Mihaela Panaitescu, Adriana Nicoleta Frone^*, Cristian Andi Nicolae, Valentin Raditoiu, Elena-Iulia Neblea, Ioana Catalina Gifu, Mircea Teodorescu. Thermal properties and morphological features of new polysaccharide-based systems. 23^rd

International Balkan Workshop on Applied Physics and Materials Science IBWAP Constanta, 9-12 July, 2025, poster presentation

4.         Gabriela – Mădălina Oprică, Catalina-Diana Usurelu, Adriana-Nicoleta Frone, Cristian-Andi Nicolae, Iulia-Elena NEBLEA, Valentin Radițoiu, Denis-Mihaela Panaitescu, Radu-Claudiu Fierascu, Physical-chemical evaluation of natural materials containing a seaweed polysaccharide, 11^th edition of the International Scientific Conference “Applications of Chemistry in Nanosciences and Biomaterials Engineering (NanoBioMat)” for young researchers, 25-27 June 2025, oral presentation, online – awarded.

5.          Cătălina-Diana Uşurelu, Gabriela Mădălina Oprică, Cristina Firincă, Cristian Andi Nicolae, Adriana Nicoleta Frone, Mircea Teodorescu, Denis Mihaela Panaitescu, A study on the modification of nanocellulose with a naturally occurring aldehyde possessing antibacterial properties, Young Researchers’ International Conference on Chemistry and Chemical Engineering (YRICCCE V) Cluj-Napoca, Romania, 8 – 10 May, 2025, oral presentation.

6.         Gabriela-Mădălina Oprică, Cătălina-Diana Uşurelu, Gabriel Vasilievici, Valentin Raditoiu, Cristian Andi Nicolae, Augusta Raluca Gabor, Denis Mihaela Panaitescu, Adriana Nicoleta Frone, The modification of nanocellulose with a sulfated polysaccharide: A physico-chemical study, Young Researchers’ International Conference on Chemistry and Chemical Engineering (YRICCCE V) Cluj-Napoca, Romania, 8 – 10 May, 2025, oral presentation.

7.         Cătălina-Diana Uşurelu, Gabriela-Mădălina Oprică, Denis Mihaela Panaitescu, Cristian Andi Nicolae, Valentin Rădiţoiu, Ioana Cătălina Gîfu, Marinela Victoria Dumitru, Mircea Teodorescu, Adriana Nicoleta Frone, New polysaccharide-based formulations with applications in biomedicine, Exploratory Workshop NeXT-Chem: Innovative Cross-Sectoral Technologies, 22-23 May 2025, Bucharest, oral presentation – awarded

8.    Cătălina-Diana Uşurelu, Gabriela Mădălina Oprică, Adriana Nicoleta Frone, Cristina Firincă, Valentin Rădiţoiu, Cristian Andi Nicolae, Mircea Teodorescu, Denis Mihaela Panaitescu, Compositions with antibacterial properties for dental tissue engineering based on biopolymers and nanocellulose modified with natural aldehydes, 9th International conference on Advanced Polymer Materials and Nanocomposites, ANM 2025 University of Aveiro, Portugal, 23-25 July 2025, oral presentation -online

Other

1. The concept of Waste2Coat project was granted with the gold medal in the frame of ”International Innovation and Invention Show EURO POLITEHNICUS 2025”, 21-23 November 2025 Bucharest, Romania.