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120 results on '"Daskalova, Albena"'

1. Biomimetic Hierarchical Structuring of PLA by Ultra-Short Laser Pulses for Processing of Tissue Engineered Matrices: Study of Cellular and Antibacterial Behavior

Author

Daskalova, Albena, Angelova, Liliya, Filipov, Emil, Aceti, Dante, Mincheva, Rosica, Carrete, Xavier, Kerdjoudj, Halima, Dubus, Marie, Chevrier, Julie, Trifonov, Anton, and Buchvarov, Ivan

Subjects
Physics - Biological Physics
Abstract

The influence of ultra-short laser modification on the surface morphology and possible chemical alteration of poly-lactic acid (PLA) matrix in respect to the optimization of cellular and antibacterial behavior were investigated in this study. Scanning electron microscopy (SEM) morphological examination of the processed PLA surface showed the formation of diverse hierarchical surface microstructures, generated by irradiation with a range of laser fluences (F) and scanning velocities (V) values. By controlling the laser parameters, diverse surface roughness can be achieved, thus influencing cellular dynamics. This surface feedback can be applied to finely tune and control diverse biomaterial surface properties like wettability, reflectivity, and biomimetics. The triggering of thermal effects, leading to the ejection of material with subsequent solidification and formation of raised rims and 3D-like hollow structures along the processed zones, demonstrated a direct correlation to the wettability of the PLA. A transition from superhydrophobic (thetha > 150 deg.) to super hydrophilic (thetha < 20 deg.) surfaces can be achieved by the creation of grooves with V = 0.6 mm/s, F = 1.7 J/cm2. The achieved hierarchical architecture affected morphology and thickness of the processed samples which were linked to the nature of ultra-short laser-material interaction effects, namely the precipitation of temperature distribution during material processing can be strongly minimized with ultrashort pulses leading to non-thermal and spatially localized effects that can facilitate volume ablation without collateral thermal damage.

Published
2021
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2. Dual-Function Femtosecond Laser: β-TCP Structuring and AgNP Synthesis via Photoreduction with Azorean Green Tea for Enhanced Osteointegration and Antibacterial Properties.

Author

Oliveira, Marco, Angelova, Liliya, Grenho, Liliana, Fernandes, Maria Helena, and Daskalova, Albena

Subjects
MESENCHYMAL stem cells, FOURIER transform infrared spectroscopy, TRANSMISSION electron microscopy, SILVER nanoparticles, BONE regeneration
Abstract

β-Tricalcium phosphate (β-TCP) is a well-established biomaterial for bone regeneration, highly regarded for its biocompatibility and osteoconductivity. However, its clinical efficacy is often compromised by susceptibility to bacterial infections. In this study, we address this limitation by integrating femtosecond (fs)-laser processing with the concurrent synthesis of silver nanoparticles (AgNPs) mediated by Azorean green tea leaf extract (GTLE), which is known for its rich antioxidant and anti-inflammatory properties. The fs laser was employed to modify the surface of β-TCP scaffolds by varying scanning velocities, fluences, and patterns. The resulting patterns, formed at lower scanning velocities, display organized nanostructures, along with enhanced roughness and wettability, as characterized by Scanning Electron Microscopy (SEM), optical profilometry, and contact angle measurements. Concurrently, the femtosecond laser facilitated the photoreduction of silver ions in the presence of GTLE, enabling the efficient synthesis of small, spherical AgNPs, as confirmed by UV–vis spectroscopy, Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). The resulting AgNP-embedded β-TCP scaffolds exhibited a significantly improved cell viability and elongation of human bone marrow mesenchymal stem cells (hBM-MSCs), alongside significant antibacterial activity against Staphylococcus aureus (S. aureus). This study underscores the transformative potential of combining femtosecond laser surface modification with GTLE-mediated AgNP synthesis, presenting a novel and effective strategy for enhancing the performance of β-TCP scaffolds in bone-tissue engineering. [ABSTRACT FROM AUTHOR]

Published
2024
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3. Ultra-short laser processing of 3D bioceramic, porous scaffolds designed by freeze foaming method for orthopedic applications.

Author

Daskalova, Albena, Ahlhelm, Matthias, Angelova, Liliya, Filipov, Emil, Avdeev, Georgi, Tatchev, Dragomir, Fernandes, Maria-Helena, Vig, Sanjana, and Buchvarov, Ivan

Subjects
BONE substitutes, LASERS, ORTHOPEDIC surgery, MANUFACTURING processes, FOAM
Abstract

Bone substitutes are widely employed for applications in orthopedic surgery for the replacement of injured bone. Among the diverse methods that are used to design 3D bioceramic matrices, Freeze Foaming has gained attention, since it provides the ability to tune the shape of the created structures. One of the major problems related to these constructs is the lack of porosity at the outwards sides (holder) of the scaffold, thus reducing the cellular affinity and creating a rejection of the implant. In this research, we aimed to develop a bone scaffold with enhanced surface properties and improved cellular affinity. The main aim was to alter the biocompatibility characteristics of the 3D bioceramic constructs. We have produced three-dimensional, complex-shaped hollow shell structures, manufactured by Additive Manufacturing processes and as a second step, filled with a ceramic suspension by the Freeze-Foaming process. 3D constructs from HAP-derived TCP and TCP/ZrO2 were synthesized by freezefoaming method and subsequently irradiated with a fs-laser (λ = 800 nm) spanning a range of parameters for achievement of optimal surface processing conditions. The designed scaffolds demonstrated enhanced topographical properties with improved porosity examined by SEM, EDX, and 3D profilometry after laser treatment. Wettability and computer tomography (CT) evaluation was also performed. The results from X-ray diffraction (XRD) and micro-Raman analysis did not show photochemical and surface or volume defects and changes after laser processing of the ceramic samples. Preliminary results from MG-63 osteoblast-like cell tests showed good cell affinity on the processed surfaces and no cytotoxic effect on the cells. [ABSTRACT FROM AUTHOR]

Published
2024
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5. Design of Laser Activated Antimicrobial Porous Tricalcium Phosphate-Hydroxyapatite Scaffolds for Orthopedic Applications

Author

Filipov, Emil, primary, Yildiz, Ridvan, additional, Dikovska, Anna, additional, Sotelo, Lamborghini, additional, Soma, Tharun, additional, Avdeev, Georgi, additional, Terziyska, Penka, additional, Christiansen, Silke, additional, Leriche, Anne, additional, Fernandes, Maria Helena, additional, and Daskalova, Albena, additional

Published
2024
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11. Single-Step Process for Titanium Surface Micro- and Nano-Structuring and In Situ Silver Nanoparticles Formation by Ultra-Short Laser Patterning

Author

Aceti, Dante Maria, primary, Filipov, Emil, additional, Angelova, Liliya, additional, Sotelo, Lamborghini, additional, Fontanot, Tommaso, additional, Yousefi, Peyman, additional, Christiansen, Silke, additional, Leuchs, Gerd, additional, Stanimirov, Stanislav, additional, Trifonov, Anton, additional, Buchvarov, Ivan, additional, and Daskalova, Albena, additional

Published
2022
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14. Ultra-Short Laser Surface Properties Optimization of Biocompatibility Characteristics of 3D Poly-ε-Caprolactone and Hydroxyapatite Composite Scaffolds

Author

Daskalova, Albena, primary, Filipov, Emil, additional, Angelova, Liliya, additional, Stefanov, Radostin, additional, Tatchev, Dragomir, additional, Avdeev, Georgi, additional, Sotelo, Lamborghini, additional, Christiansen, Silke, additional, Sarau, George, additional, Leuchs, Gerd, additional, Iordanova, Ekaterina, additional, and Buchvarov, Ivan, additional

Published
2021
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15. Biomimetic Hierarchical Structuring of PLA by Ultra-Short Laser Pulses for Processing of Tissue Engineered Matrices: Study of Cellular and Antibacterial Behavior

Author

Daskalova, Albena, primary, Angelova, Liliya, additional, Filipov, Emil, additional, Aceti, Dante, additional, Mincheva, Rosica, additional, Carrete, Xavier, additional, Kerdjoudj, Halima, additional, Dubus, Marie, additional, Chevrier, Julie, additional, Trifonov, Anton, additional, and Buchvarov, Ivan, additional

Published
2021
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18. Defined nano-structuring with ultrashort pulses in gelatin biopolymer films for tissue-engineering

Author

Nathala Chandra S.R., Daskalova Albena, Bliznakova Irina, Lueftenegger Stefan, Zhelyazkova Alexandra, Enikoe Seres, Ganz Thomas, and Husinsky Wolfgang

Subjects
Engineering (General). Civil engineering (General), TA1-2040
Abstract

We compare the morphological modifications in gelatin films, induced with an 800nm femtosecond amplifier, in subject of the number of input pulses and the input pulse duration. Foam is formed in all cases, but only under certain conditions the desirable structures that mimic the native subcellular matrix are formed. The number of input pulses significantly changes the foam structure, allowing a well-defined nano-structuring for optimal tissue-engineering.

Published
2013
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21. Towards laser based methods for improving surface properties of materials.

Author

Daskalova, Albena, Ahlhelm, Matthias, Angelova, Liliya, and Buchvarov, Ivan

Subjects
SURFACE properties, SURFACES (Technology), LASER beams, LASER pulses, SURFACE preparation, ULTRA-short pulsed lasers, PULSED lasers
Abstract

Traditional chemical modification techniques used to alter the surface properties of diverse biomaterials possess drawbacks, such as leaving additional chemical toxicity from the solvents used and altering the mechanical stability. As an alternative approach for surface treatment, ultra-short pulsed laser processing (Fig. 1) is a non-contact method that enables a unique route to manipulate diverse biomaterial surfaces without severe thermal damage leading to heat-affected zones. Application of ultra-short laser radiation induces precise surface modification of scaffolds and allows the creation of multifunctional geometries with the potential to affect the biomimetic and antimicrobial properties of the constructs. By finely tuning the laser processing parameters (scanning velocity (V), laser fluence (F), and a number of applied laser pulses (N), it is possible to influence the surface roughness, thus altering the wettability of the materials without disrupting their chemical composition. The conducted research was performed on a number of materials and has demonstrated that surface topography has a great influence on the biomimetic and antimicrobial behavior of materials used in biomedicine and in everyday life. [ABSTRACT FROM AUTHOR]

Published
2024

48. Forty years after the first dark resonance experiment: an overview of the COSMA project results

Author

Dreischuh, Tanja, Gateva, Sanka, Daskalova, Albena, Serafetinides, Alexandros, Mariotti, E., Bevilacqua, G., Biancalana, V., Cecchi, R., Dancheva, Y., Khanbekyan, Alen, Marinelli, C., Moi, L., Stiaccini, L., Cartaleva, S., Andreeva, C., Alipieva, E., Gateva, S., Krasteva, A., Slavov, D., Taskova, E. T., Taslakov, M., Todorov, P., Tsvetkov, S., Wilson Gordon, A., Margalit, L., Gawlik, W., Pustelny, S., Stabrawa, A., Sudyka, J., Wojciechowski, A., Renzoni, F., Deans, C., Hussain, S., Marmugi, L., Rassi, D., Ozun, O., Sarkisyan, D., Azizbekyan, H., Drampyan, R., Khanbekyan, Alek., Mirzoyan, R., Papoyan, A., Sargsyan, A., Shmavonyan, S., Tonoyan, A., Ghosh, P. N., Dey, S., Mitra, S., Ray, B., Nasyrov, K. A., Chapovsky, P., Entin, V., Nikolov, N., Petrov, N., Budker, D., Patton, B., Wickenbrock, A., Zhivun, L., and Gozzini, S.

Published
2016
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