7^th International Conference and Expo on Ceramics and Composite Materials June 21-22, 2021 Berlin, Germany

Biography:

Imre Hegedus has started his research activity at Department of Chemistry and Chemical Informatics, University of Szeged in 2003 and he studied quantum chemistry for modelling the optimal spatial structure of selenocysteine amino-acid. From 2005 he had worked at Research Institute of Biomolecular and Process Engineering at University of Pannonia (Veszprem, Hungary) where he has earned his PhD degree. His main research areas are synthesis and study of enzyme nanoparticles and he applied them as industrial biocatalysts as well as protein drug carriers. He has synthesized dendrimers for application them as drug carriers. Other drug carriers as protein nanoparticles, and nanoemulsions have also been synthesized. From 2020 he is working in Department of Biophysics and Radiation Biology in Semmelweis University, Budapest in the Nanobiotechnology and In Vivo Imaging Centre. His research interests lie in nanoparticle synthesis for clinical therapeutic and diagnostic PET/SPECT applications, and nanomaterial characterization, using atomic force microscopy.

Abstract:

Statement of the Problem: Enzyme nanoparticles represent a new class of nanomaterials with acceptable biocatalytic activity and very long life-time. Polymerization initiated from the modified surface of the enzyme (see Image, Step I and II) leads to enzyme molecules covered with a polymer layer. These may have at least one order of magnitude longer lifetime than that of free enzymes. However, their bio-catalytic activity is at least about 50% less than that of free enzymes. It is not clear how the size of the polymer layer and the strength of enzymepolymer bond influence the stability of enzyme nanoparticles.

Methodology & Theoretical Orientation: α-Chymotrypsin enzyme (bovine) was used for the synthesis. Enzyme nanoparticles containing covalent bond (CEN), ionic binding (IEN) and connected with van der Waals forces (vEN) between enzyme molecule and polymer layer are synthesized (see image: SYNTHESIS) and their bio-catalytic activity was investigated at 50 oC (optimal temperature 37 oC). All products were stirred with 100 rpm and samples were withdrawn from time to time for standard activity measurements (ref. 1.)

Findings: The results show that there is a significant difference between the stability of enzyme nanoparticles synthesized by different methods. CEN has the longest lifetime (about 1.7 hour even at 50 oC), when the enzyme:monomer ratio (E/M) during the synthesis is 1:33, but it is the shortest when E/M = 1:18. There is no significant difference between half-lives of E, IEN, vEN and CEN when E/M=1:18 (value is about 0.1 h in all of these cases) (See image: HEAT STABILITY).

Conclusion & Significance: It seems that the minimal amount of E/M for synthesis of efficient product is about 1:30. This ratio results significant enhance of its half-lifetime (ca. 17 times). Enzymes stabilized by polymer layer with ionic and van der Waals interactions could not result in significant stabilization.

Biography:

Elena Grosu has her expertise in obtaining new polymeric composites with controlled properties, such as antibacterial and prolonged use; development of technologies regarding the compounding of thermoplastic polymers, with biocompatibility properties for disposable plastic medical devices; development of new polymeric composites with controlled release of active substances for medical applications; obtaining new polymeric materials with improved antioxidant properties; obtaining biodegradable polymeric composites for medical applications; analysis of the rheological properties of polymeric receptors by determining the melt flow index (MFI) and machinability on the Brabender plastograph; testing the thermal properties of polymeric materials by DSC, physical-mechanical properties (tensile strength, elongation at break, shock resistance Charpy and Izod, FTIR), morphological by SEM.

Abstract:

Some diseases that require the patient to lie down for a long time are associated with the appearance of bedsores on large parts of the human body, due to the pressure subjection of different portions, especially the hips and buttocks. Damaged skin is exposed to microbial infections, which delays the healing process and increases suffering due to pain. Patients should apply andages directly to the damaged skin to protect it from direct contact with clothing and to speed up the healing process. Numerous researches have been carried out to achieve highperformance wound dressings that improve the health of patients. Based on prior studies performed on thiourea derivatives antimicrobial properties, in this paper we present four wound dressing compositions based on medical grade water soluble polymers (poloxamer, β-cyclodextrine, polyvinylpyrolidone, PVA) and additives, named AM1, AM2, AM3, AM4, loaded with new benzoylthiourea derivatives substituted with fluorine atoms named CTEp87, CTEp89, CTEp93, in order to increase the antimicrobial, antifungal and antiviral properties. Before clinical studies, we present some preclinical tests of wound dressing compositions that are mandatory, namely:

- qualitative determination of the antimicrobial effect of the compounds tested by the spot seeding technique.

- quantitative testing performed by the method of serial microdilutions in liquid medium.

- study of the influence of the tested compounds on the development of microbial biofilms on inert substrate.

- testing the adhesion capacity to the polymeric substrate functionalized with benzoylthiourea-derivatives active substances, using the method of determining the number of CFU/ml.

Microbial strains were selected according to the standard “SR EN 14885

-Chemical disinfectants and antiseptics - Application of European Standards for chemical disinfectants and antiseptics”

The antimicrobial efficacy has been reported against Staphylococcus aureus ATCC 25923, P. aeruginosa ATTC27853, Candida albicans ATCC 10231 grown on PDA (potato dextrose agar) media.

Recent Publications

1. Limban C., Chifiriuc M. C., Caproiu M. T., Dumitrascu F., Ferbinteanu M., Pintilie L., Stefaniu A., Vlad I. M., Bleotu C., Marutescu L. G., Nuta D. C., (2020) New substituted benzoylthiourea derivatives: from design to antimicrobial applications benzoylthiourea derivatives: from design to antimicrobial applications. Molecules 25:1478.

2. Grosu E., Trifoi A., Rapa M., Gherman T. M., Turcanu A., Filip P., (2018) Study of the drug diffusion through polymeric membranes. Rev. Chim. 69: 783 – 789.

3. Grosu E., Ficai A., Rapa M., Vlad G., Jecu L., (2013) Selecting medical grade polymers and testing for achieving antibacterial devices tubular prosthetic. Journal of optoelectronics and advanced materials, 7-8: 905 – 910.

4. Fierascu I., Rădițoiu V., Nicolae C.A., Rădițoiu A., Dițu L.M., (2019) Analytical characterization and potential antimicrobial and photocatalytic applications of metal-substituted hydroxyapatite materials. Analytical Letters, 52 (15):2332-2347.

5. Fierascu I., Rădițoiu V., Nicolae C.A., Rădițoiu A., Dițu L.M., (2019) Analytical characterization and potential antimicrobial and photocatalytic applications of metal-substituted hydroxyapatite materials. Analytical Letters, 52 (15):2332-2347.

6. da Silva L. P., Reis R. L., Correlo V. M., Marques A. P., (2019) Hydrogel-based strategies to advance therapies for chronic skin wounds. Annual review of biomedical engineering, 21:145-169.

Biography:

Abstract:

With the increase of the harmful effects of fossil-based adhesives, the elaboration of adhesives from renewable resources was increasingly in demand by the industries eco-friendly. So, in order to present some solutions for these industries, the petroleum phenolic compounds were replaced in this study by natural and renewable resources. In this research, we propose to extract phenolic compounds from the Moroccan bark of Acacia Mollissima using a simple extraction method (a traditional maceration). We choose this spice because it contains a higher content of condensed tannins (already used to made bio-based wood adhesives). The physical, thermal, and thermo-mechanical properties of the developed adhesives were evaluated according to normative tests. The good quality of the adhesives elaborated permitted their use to made bio-based wood composites. In this study, plywood with three panels was developed and the bonding quality of these panels was compared with a standard formulation of synthetic adhesives. The mechanical properties of the plywood panels produced with bio-based adhesives showed an excellent quality of the panels compared with the standard formulations already used to made wood panels and allowed their applications in a dry application when the humidity exceed 60% a few week per an.

Biography:

Dr. Jihua Chen is a research staff at the Center for Nanophase Materials Sciences, Oak Ridge National Laboratory. He obtained a PhD in Macromolecular Science and Engineering from the University of Michigan at Ann Arbor in 2006, followed by a postdoctoral position at the University of Minnesota, Twin Cities before joining ORNL. He served as a reviewer for various scientific journals and research programs. He is an author or coauthor of 150 peer reviewed publications in areas of ion and electron conducting polymers, block copolymers, polymer brushes, biomimetic materials, organic semiconductors, as well as nanostructured hybrid materials for energy and medicine applications.

Abstract:

Crystalline complexes containing polymeric components are found in some of the most amazing materials that exist in nature. For example, spider silk has extruded protein based nanocrystals in an elastic matrix. Calcium carbonate crystals guided in nanoconfinement with natural polymer template contribute to the fine appearance of a pearl and toughness of a shell. Efforts are underway to transfer some of that knowledge to the field of organic electronics and solid state ionics. Herein we present three case studies in light of experimental techniques including low dose transmission electron microscopy and electrical measurements. In the first case, polymer electrolytes with mitigated crystal growth and increased charge hopping provide enhanced ion transport. In the second example, additive guided organic semiconductor growth leads to optimized grain structures and crystal formation for thin film transistors. Finally, progress has been made in polymer-salt complexes in order to achieve enhanced performance for energy storage applications.

Biography:

Abstract:

Cytotoxic and pro-regenerative effects of biogas: 12 – well plates with 1.5 ml of medium per

Well and inserts with or without biogas and 0.5 ml were preincubated in 34°C, 90% of humidity and 5% CO2 to the time of cells’ seeding. Next 2 x 105 hFOB 1.19 cells were seeded into each well. Plates were incubated for 48 h in previous descripted conditions then Proliferation and cytotoxicity test were conducted. Cytotoxic and proregenrative effects of composites.

Direct method: Prior the experiment the composites were inserted into 24 well plates and Immersed in 1 ml of culture medium for 1 hour. Sterilized Ranching rings were placed on the top of the composites followed by hFOB 1.19 cell seeding. For each well 5x104/cm2 hFOB were Seeded inside the Ranching ring. Plates were incubated for 1 hour in 34°C and 5% CO2 to allow cells attachment to the composites. After 1 hour rings were removed, and cells were incubated for 48 h. After that time the cell viability was estimated by mitochondrial activity measurement (WST-1 test) and Cytotoxicity was measured by the leakage of lactate dehydrogenase (LDH cytotoxicity assay). Indirect method: Different composites were inserted into 24 – well plates and immersed in 1,1ml culture medium for 24 hours in 34°C and 5% CO2. After that time the extract was collected. Day prior the experiment hFOB 1.19 cell were seeded at density 5x104/cm2 on 24 – well plates. On the day of experiment medium from wells were removed and collected extracts were added On the cells and then incubated for 48 h 34°C and 5% CO2. After incubation time the cell Viability was estimated by mitochondrial activity measurement (WST-1 test) and cytotoxicity.