Biocomposites from polyhydroxyalkanoates (PHAs) and nanocellulose (NC) are cutting edge materials for in vivo biomedical application. Poly(3-hydroxybutyrate) (PHB), the most studied of the PHAs, is available as industrial grade and it is considered as viable alternative of petroleum-based materials. However, PHB and cellulose themselves have no antibacterial activity to prevent bacterial infections associated with medical devices that constitute the most important cause of hospital death which could be prevented. The scope of this project is to obtain PHB/NC biocomposites with antibacterial activity using eco-friendly submerged liquid plasma (SLP) and nanotechnology. The research topic of plasma submerged in liquids is new but very important for the functionalization of nanaomaterials or synthesis of unconventional polymers with valuable properties for biomedical applications. In the frame of CELLAB-SLP, the biomaterial and eco-friendly technology will constitute the experimental model that will be developed and tested at lab-scale. 

The objective of the project is to develop a new biomaterial with integrated antibacterial activity and a technology to obtain this biomaterial. The new biocomposite must have (i) good processability by compression, extrusion or injection molding in films, plates, tubes or rods as models for biomedical devices; (ii) good mechanical properties and thermal stability; (iii) strong and persistent antibacterial activity beside biocompatibility.

The new biomaterial which will be developed in the frame of this project (lab-prototype) and the technology will be patented. The non-patentable results will be disseminated by conferences and articles. 

ICECHIM:

Panaitescu Denis

Vuluga Zina

Corobea Mihai

Frone Adriana

Chiulan Ioana

Bogdan Trica

Nicolae Cristian

Purcar Violeta

Gabor Raluca

Iorga Michaela

Florea Dorel

Radu Dorian

Corduneanu Gabriela

Anghel Aurelia

INFLPR

Vizireanu Sorin

Dinescu Gheorghe

Mitu Bogdana

Ionita Rosini

Ionita Maria

Stoica Daniel

Satulu Veronica

Teodorescu Maximilian

1. Surface modification of nanocellulose by plasma treatment in contact or submerge in liquids; Synthesis of new PHB/NC biomaterials with antibacterial activity using plasma treatment; Design of the SLP process parameters for controlled composition;
2. Plasma treatment of PHB/NC biomaterials; Antibacterial tests; Prototype built in the lab; Elaboration and validation of laboratory technology; 

Articles

1. Panaitescu DM, Lupescu I, Frone AN, Chiulan I, Nicolae CA, Tofan V, Stefaniu A, Somoghi R, Trusca R., Medium chain-length polyhydroxyalkanoate copolymer modified by bacterial cellulose for medical devices. Biomacromolecules. 2017 Oct 9;18(10):3222-3232. doi: 10.1021/acs.biomac.7b00855.

2. Ioana Chiulan, Adriana Nicoleta Frone, Denis Mihaela Panaitescu, Cristian Andi Nicolae, Roxana Trusca, Surface properties, thermal and mechanical characteristics of poly(vinyl alcohol) – starch - bacterial cellulose composite films, J. Appl. Polym. Sci. 2018, 135, 45800. doi: 10.1002/app.45800.

3. Vizireanu, S., Ionita, M.D., Ionita, R.E., Stoica, S.D., Teodorescu, C.M., Husanu, M.A., Apostol, N.G., Baibarac, M., Panaitescu, D., Dinescu, G., Aging phenomena and wettability control of plasma deposited carbon nanowall layers, Plasma Processes and Polymers, 2017, 14(11).

4. D. M. Panaitescu, S. Vizireanu, C. A. Nicolae, A. N. Frone, A. Casarica, L. G. Carpen and G. Dinescu, Treatment of Nanocellulose by Submerged Liquid Plasma for Surface Functionalization, Nanomaterials 2018, 8(7), 467; https://doi.org/10.3390/nano8070467

5. S.D. Stoica, S. Vizireanu, T. Acsente, G. Dinescu, Hybrid Nanomaterial Architectures: Combining Layers of Carbon Nanowalls, Nanotubes, and Particles, Plasma Chemistry and Plasma Processing, 2018, 38, 695-706.

Invited lecture

1. S. Vizireanu, S.D. Stoica, M.D. Ionita, A. Lazea Stoyanova, L. Nistor, G. Dinescu, Plasma Fabrication, Functionalization and Application of Vertically Oriented Graphene, Twentieth international summer school on vacuum, electron and ion technology, Sozopol, Bulgaria, 25-29/09/2017

Conferences

1. D. M. Panaitescu, I. Lupescu, A. N. Frone, I. Chiulan, C. Nicolae, Z. Vuluga, R. Gabor, G. Dinescu, S. Vizireanu, D. Ionita, A. Casarica, Polyhydroxyalkanoate/bacterial cellulose nanofibers biocomposites with modified surface properties, Fifth International Symposium Frontiers in Polymer Science 17-19 May 2017, Seville, Spain.

2. Denis Panaitescu, Adriana Frone, Sorin Vizireanu, George Dinescu, Ioana Chiulan, Cristian Nicolae, Daniela Ionita, Lavinia Carpen, Cosmin Corobea, Violeta Purcar, Cellulose with modified surface properties by plasma treatment, 19th International Conference on Advanced Materials, ROCAM 2017

3. S. Vizireanu, M.D. Ionita, E. R. Ionita, S.D. Stoica, L. Carpen, M. Teodorescu, I. Ion, D. Panaitescu, G. Dinescu, Nanomaterials processing by plasma in liquids, P6-01, Conference on Plasma Physics and Applications, Magurele, Bucharest, Romania, 15-20/06/2017.

4. V. Satulu, B. Mitu, S. Vizireanu, M. Pandele, S.I. Voicu, L. Kravets, G. Dinescu/Synthesis of composite membranes by RF magnetron sputtering/ RICCCE 20 - 20th Romanian International Conference on Chemistry and Chemical Engineering, Poaiana Brasov Romania, 6-9/09/2017.

5. L.G. Carpen, M. Teodorescu, M.D. Ionita, E.R. Ionita, G. Dinescu, Diagnostic of plasma-liquid mixing and methylene blue decomposition using a RF atmospheric jet, International Conference on Plasmas with Liquids (ICPL 2017), March 5-9, 2017, Prague Czech Republic.

6. S. Vizireanu, M.D. Ionita, S. D. Stoica, M. M. Ionita, Ioana Mitu, L. C. Nistor, G. Dinescu, Nitrogen incorporation in reduced graphene oxide suspension by submerged plasma jet International Conference on Plasmas with Liquids (ICPL 2017), March 5-9, 2017, Prague Czech Republic.

7. S. Vizirean, S.D. Stoica, M. D. Ionita, A. Lazea Stoyanova, L.C. Nistor, G. Dinescu/ Plasma synthesis and treatment for obtaining functional hybrid nanomaterials/, 5th International Conference on Multifunctional, Hybrid and Nanomaterials, Lisabon, Portugalia, 6-10/03/2017

8. S. Vizireanu, M.D. Ionita, S. D. Stoica, L. Carpen, M. Teodorescu, I. Ion, M. Ionita, G. Dinescu, Functionalization of reduced graphene oxide suspension by submerged plasma jet, conferinta European Graphene Forum, Paris, Franta, 26-29/04/2017

9. S. Vizireanu, M. D. Ionita, E. R. Ionita, D. S. Stoica, L. G. Carpen, M. Teodorescu, D. Panaitescu, G. Dinescu, Plasma in liquid for nanocellulose modification, 16th International Conference on Plasma Surface Engineering, Congress Center Garmisch-Partenkirchen Germany, 2018.

Patents:

1. Patent claim OSIM: A/00177/13.03.2018 - Process for treating micro and nanocellulose using submerged liquid plasma treatment and process for obtaining nanocomposites from biopolymers and treated cellulose; authors: Denis Mihaela Panaitescu, Adriana Nicoleta Frone, Ioana Chiulan, Cristian Andi Nicolae, Sorin Vizireanu, Maria Daniela Ionita, Eusebiu Rosini Ionita, Gheorghe Dinescu.

Phase 1/2017 – Surface modification of nanocellulose by plasma treatment in contact or submerge in liquids; Synthesis of new PHB/NC biomaterials with antibacterial activity using plasma treatment; Design of the SLP process parameters for controlled composition.

Duration: 03/01/2017 - 29/12/2017

Expected results:

-          Parameter values for plasma systems in liquid (power, flow range, treatment time, gases);

-          PHB composites with NC modified in various working conditions;

-          Functional plasma jet systems working in suspensions of nanocellulose;

-          Communications: PHB/modified NC composites; SLP systems;

-          Report with scientific data on biomaterial characteristics before and after treatment.

Activities:

Activity I.1Preparation of nanocellulose according to the procedures patented in the frame of the previous projects, and verification of thermal stability and nanodimension (NIRD for Chenistry and Petrocehmistry ICECHIM)

Activity I.2Plasma treatment of NC in water suspension by in contact and submerge techniques (NIRD for Laser, Plasma and Radiation Physics INFLPR)

Activity I.3Characterization of modified NC: composition, dimensions, surface modification (ICECHIM and INFLPR)

Activity I.4 Preliminary conditions established for plasma treatment of NC suspensions in water (ICECHIM and INFLPR)

Activity I.5 Surface modification of NC using plasma treatment in liquids mixture starting from the conditions established in the previous phase (INFLPR)

Activity I.6 Characterization of different modified NC (ICECHIM and INFLPR)

Activity I.7 PHB/modified NC (I) composites by solution casting or melt processing; characterization of composite materials (ICECHIM)

Activity I.8 Surface functionalization of nanocellulose by plasma treatment in liquids using precursor; Characterization of modified NC (ICECHIM and INFLPR)

Activity I.9 Preparation of PHB/modified NC (II) composites by solution casting or melt processing and characterization of composite materials (ICECHIM)

Activity I.10 Dissemination of non-patentable results (ICECHIM and INFLPR)

Results:

-          Parameter values for plasma systems in liquid (established: power, flow range, treatment time, mixture of gases);

-          PHB composites with NC modified in various working conditions;

-          Functional plasma jet systems working in suspensions of nanocellulose;

-          Report with scientific data on biomaterial characteristics before and after treatment;

-          Dissemination: 3 published papers with polymer - NC composites and SLP systems; 8 communications

Phase II

Title: Plasma treatment of PHB/NC biomaterials; Antibacterial tests; Prototype built in the lab; Elaboration and validation of laboratory technology.

Period: 01/01/2018 - 03/07/2018

Summary of the activity report phase II

The CELLAB-SLP project aims to obtain biocomposites from polyhydroxyalkanoates (PHA) and nanocellulose (NC) that show antibacterial activity due to the SLP treatment. In this phase, PHB/ modified NC composites were prepared by direct plasma treatment to imprint antibacterial activity; the biocompatibility and antibacterial activity were tested in an independent laboratory for validation. By direct plasma treatment, an increase in mechanical properties and hydrophilicity of PHB/BC composites has been achieved without compromising the thermal stability. The antibacterial activity increased by 44% and 60% for the two types of biocomposites using the colony counting method. The new biocomposites have been processed in the form of films/plates and in the form of cylindrical bodies (rods) using processing equipments specific to thermoplastic polymers, i.e. melt mixing and compression machines as well as an injection molding machine. Following the establishment of the optimal parameters on these equipments, films and rods prototypes of the selected biocomposites were made on these equipments, which can easily up-scaled at industrial level, thus achieving the TRL4. Thus, the technology for obtaining plasma treated biocomposites containing micro and nanocellulose in order to increase the antibacterial effect (A) and SLP plasma treated micro- or nanocellulose technology (B) were elaborated. Both laboratory technologies have been validated by demonstrating the chemical changes at the surface of nanocellulose and by analyzing the inhibition sites on the basis of the EUCAST or CLSI standards.