TY  - CHAP
AU  - Pajić-Lijaković, Ivana
AU  - Milivojević, Milan
AU  - Lević, Steva
AU  - Trifković, Kata T.
AU  - Balanč, Bojana
AU  - Nedović, Viktor
AU  - Stevanović-Dajić, Zora
AU  - Radosević, Radenko
AU  - Bugarski, Branko
PY  - 2019
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/4162
AB  - Some of the main rheological properties that Ca-alginate hydrogel matrix should satisfy for biomedical and biotechnological applications are the matrix viscoelasticity and the ability of stress relaxation. Although alginate satisfies both of them, experimental data note that cell growth is significantly reduced by microenvironmental effects. Microenvironmental restriction effects are connected to matrix resistance stress accumulation. Matrix stress is generated within the boundary layers around the cell aggregates under compression caused by cell rearrangement and growth. Simultaneously induced relaxation phenomena of both subsystems: (1) immobilized cells and (2) hydrogel matrix occur at three time scales through successive relaxation cycles. Complex dynamics of matrix compression intensifies mechanical and electrostatic cell-matrix interactions. Minimizing of the resistance stress is the strategy for improving the matrix performances. Cell action could be simulated in the experiments without cells during repeated stress relaxation cycles. We consider the physical and chemical modifications of Ca-alginate hydrogel.
T2  - Materials for Biomedical Engineering: Bioactive Materials, Properties, and Applications
T1  - Matrix resistance stress reduction-prerequisite for achieving higher concentration of immobilized cells
EP  - 306
SP  - 281
DO  - 10.1016/B978-0-12-818431-8.00009-X
ER  - 

@inbook{
author = "Pajić-Lijaković, Ivana and Milivojević, Milan and Lević, Steva and Trifković, Kata T. and Balanč, Bojana and Nedović, Viktor and Stevanović-Dajić, Zora and Radosević, Radenko and Bugarski, Branko",
year = "2019",
abstract = "Some of the main rheological properties that Ca-alginate hydrogel matrix should satisfy for biomedical and biotechnological applications are the matrix viscoelasticity and the ability of stress relaxation. Although alginate satisfies both of them, experimental data note that cell growth is significantly reduced by microenvironmental effects. Microenvironmental restriction effects are connected to matrix resistance stress accumulation. Matrix stress is generated within the boundary layers around the cell aggregates under compression caused by cell rearrangement and growth. Simultaneously induced relaxation phenomena of both subsystems: (1) immobilized cells and (2) hydrogel matrix occur at three time scales through successive relaxation cycles. Complex dynamics of matrix compression intensifies mechanical and electrostatic cell-matrix interactions. Minimizing of the resistance stress is the strategy for improving the matrix performances. Cell action could be simulated in the experiments without cells during repeated stress relaxation cycles. We consider the physical and chemical modifications of Ca-alginate hydrogel.",
journal = "Materials for Biomedical Engineering: Bioactive Materials, Properties, and Applications",
booktitle = "Matrix resistance stress reduction-prerequisite for achieving higher concentration of immobilized cells",
pages = "306-281",
doi = "10.1016/B978-0-12-818431-8.00009-X"
}

Pajić-Lijaković, I., Milivojević, M., Lević, S., Trifković, K. T., Balanč, B., Nedović, V., Stevanović-Dajić, Z., Radosević, R.,& Bugarski, B.. (2019). Matrix resistance stress reduction-prerequisite for achieving higher concentration of immobilized cells. in Materials for Biomedical Engineering: Bioactive Materials, Properties, and Applications, 281-306.
https://doi.org/10.1016/B978-0-12-818431-8.00009-X

Pajić-Lijaković I, Milivojević M, Lević S, Trifković KT, Balanč B, Nedović V, Stevanović-Dajić Z, Radosević R, Bugarski B. Matrix resistance stress reduction-prerequisite for achieving higher concentration of immobilized cells. in Materials for Biomedical Engineering: Bioactive Materials, Properties, and Applications. 2019;:281-306.
doi:10.1016/B978-0-12-818431-8.00009-X .

Pajić-Lijaković, Ivana, Milivojević, Milan, Lević, Steva, Trifković, Kata T., Balanč, Bojana, Nedović, Viktor, Stevanović-Dajić, Zora, Radosević, Radenko, Bugarski, Branko, "Matrix resistance stress reduction-prerequisite for achieving higher concentration of immobilized cells" in Materials for Biomedical Engineering: Bioactive Materials, Properties, and Applications (2019):281-306,
https://doi.org/10.1016/B978-0-12-818431-8.00009-X . .

TY  - JOUR
AU  - Pajić-Lijaković, Ivana
AU  - Milivojević, Milan
AU  - Lević, Steva
AU  - Trifković, Kata T.
AU  - Stevanović-Dajić, Zora
AU  - Radosević, Radenko
AU  - Nedović, Viktor
AU  - Bugarski, Branko
PY  - 2017
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3666
AB  - Microenvironmentally restricted yeast cell growth within Ca-alginate beads with and without entrapped gas bubbles was considered based on experimental data. Cell growth dynamics was described by (1) the dimensionless cell number density as a function of the cell growth time and (2) the cell distribution per bead cross sections. One of the key control parameters for bioprocess optimization is the matrix resistance stress generated during immobilized cell expansion. The dynamics of the increase in matrix stress was described theoretically based on a multi-scale mathematical model. In order to estimate and reduce the accumulation of matrix stress we considered repeated stress relaxation cycles in separate rheological experiments without immobilized cells. The results revealed that the increase in resistance stress within the Ca-alginate matrix was significant (similar to 7 kPa) after 10 repeated cycles, even under a low compression strain of 2% per cycle. The stress could be reduced by using the Ca-alginate matrix with entrapped gas bubbles. The final cell concentration within the beads with entrapped bubbles was 3.3 times higher in comparison with the beads without bubbles. The bubbles could locally amortize the compression effects within the surrounding cell clusters.
PB  - Elsevier Sci Ltd, Oxford
T2  - Process Biochemistry
T1  - Matrix resistance stress: A key parameter for immobilized cell growth regulation
EP  - 43
SP  - 30
VL  - 52
DO  - 10.1016/j.procbio.2016.10.017
ER  - 

@article{
author = "Pajić-Lijaković, Ivana and Milivojević, Milan and Lević, Steva and Trifković, Kata T. and Stevanović-Dajić, Zora and Radosević, Radenko and Nedović, Viktor and Bugarski, Branko",
year = "2017",
abstract = "Microenvironmentally restricted yeast cell growth within Ca-alginate beads with and without entrapped gas bubbles was considered based on experimental data. Cell growth dynamics was described by (1) the dimensionless cell number density as a function of the cell growth time and (2) the cell distribution per bead cross sections. One of the key control parameters for bioprocess optimization is the matrix resistance stress generated during immobilized cell expansion. The dynamics of the increase in matrix stress was described theoretically based on a multi-scale mathematical model. In order to estimate and reduce the accumulation of matrix stress we considered repeated stress relaxation cycles in separate rheological experiments without immobilized cells. The results revealed that the increase in resistance stress within the Ca-alginate matrix was significant (similar to 7 kPa) after 10 repeated cycles, even under a low compression strain of 2% per cycle. The stress could be reduced by using the Ca-alginate matrix with entrapped gas bubbles. The final cell concentration within the beads with entrapped bubbles was 3.3 times higher in comparison with the beads without bubbles. The bubbles could locally amortize the compression effects within the surrounding cell clusters.",
publisher = "Elsevier Sci Ltd, Oxford",
journal = "Process Biochemistry",
title = "Matrix resistance stress: A key parameter for immobilized cell growth regulation",
pages = "43-30",
volume = "52",
doi = "10.1016/j.procbio.2016.10.017"
}

Pajić-Lijaković, I., Milivojević, M., Lević, S., Trifković, K. T., Stevanović-Dajić, Z., Radosević, R., Nedović, V.,& Bugarski, B.. (2017). Matrix resistance stress: A key parameter for immobilized cell growth regulation. in Process Biochemistry
Elsevier Sci Ltd, Oxford., 52, 30-43.
https://doi.org/10.1016/j.procbio.2016.10.017

Pajić-Lijaković I, Milivojević M, Lević S, Trifković KT, Stevanović-Dajić Z, Radosević R, Nedović V, Bugarski B. Matrix resistance stress: A key parameter for immobilized cell growth regulation. in Process Biochemistry. 2017;52:30-43.
doi:10.1016/j.procbio.2016.10.017 .

Pajić-Lijaković, Ivana, Milivojević, Milan, Lević, Steva, Trifković, Kata T., Stevanović-Dajić, Zora, Radosević, Radenko, Nedović, Viktor, Bugarski, Branko, "Matrix resistance stress: A key parameter for immobilized cell growth regulation" in Process Biochemistry, 52 (2017):30-43,
https://doi.org/10.1016/j.procbio.2016.10.017 . .

TY  - JOUR
AU  - Pajić-Lijaković, Ivana
AU  - Lević, Steva
AU  - Hadnadjev, Miroslav
AU  - Stevanović-Dajić, Zora
AU  - Radosević, Radenko
AU  - Nedović, Viktor
AU  - Bugarski, Branko
PY  - 2015
UR  - http://TechnoRep.tmf.bg.ac.rs/handle/123456789/3140
AB  - Structural changes of Ca-alginate bead due to yeast cell loading and the impact on their mechanical properties were studied based on experimental data of cell number density per beads, cell rearrangement within the bead surface and core regions, bead average volume and density, bead storage and loss moduli. Structural changes could be explained by (1) mechanical and electrostatic cell-matrix interactions and (2) chemical interactions of the matrix with the components of the nutrition medium which include: wash out of Ca2+ ions by presence of non-gelling ions and by chelating compounds such as phosphate. According to obtained results, it was estimated that: (1) cell-matrix electrostatic interactions within the hydrogel matrix at t=0 induced the bead weakening, (2) wash out of Ca2+ ions by presence of non-gelling ions and by chelating compounds such as phosphate led to the bead weakening (regime 1, t is an element of (left perpendicular0, 2 daysright perpendicular), (3) the bead stiffness remained constant (regime 2, t is an element of (left perpendicular2, 4 daysright perpendicular)) and (4) the bead reinforcement was caused by cell clusters rapid increase and their inter connections within the bead surface region (regime 3, t is an element of (left perpendicular4, 5 daysright perpendicular)). Regulation of the matrix resistance stress and the rate of its change could lead to decrease of the micro-environmental restriction effects and the whole process optimization.
PB  - Elsevier Science Bv, Amsterdam
T2  - Biochemical Engineering Journal
T1  - Structural changes of Ca-alginate beads caused by immobilized yeast cell growth
EP  - 38
SP  - 32
VL  - 103
DO  - 10.1016/j.bej.2015.06.016
ER  - 

@article{
author = "Pajić-Lijaković, Ivana and Lević, Steva and Hadnadjev, Miroslav and Stevanović-Dajić, Zora and Radosević, Radenko and Nedović, Viktor and Bugarski, Branko",
year = "2015",
abstract = "Structural changes of Ca-alginate bead due to yeast cell loading and the impact on their mechanical properties were studied based on experimental data of cell number density per beads, cell rearrangement within the bead surface and core regions, bead average volume and density, bead storage and loss moduli. Structural changes could be explained by (1) mechanical and electrostatic cell-matrix interactions and (2) chemical interactions of the matrix with the components of the nutrition medium which include: wash out of Ca2+ ions by presence of non-gelling ions and by chelating compounds such as phosphate. According to obtained results, it was estimated that: (1) cell-matrix electrostatic interactions within the hydrogel matrix at t=0 induced the bead weakening, (2) wash out of Ca2+ ions by presence of non-gelling ions and by chelating compounds such as phosphate led to the bead weakening (regime 1, t is an element of (left perpendicular0, 2 daysright perpendicular), (3) the bead stiffness remained constant (regime 2, t is an element of (left perpendicular2, 4 daysright perpendicular)) and (4) the bead reinforcement was caused by cell clusters rapid increase and their inter connections within the bead surface region (regime 3, t is an element of (left perpendicular4, 5 daysright perpendicular)). Regulation of the matrix resistance stress and the rate of its change could lead to decrease of the micro-environmental restriction effects and the whole process optimization.",
publisher = "Elsevier Science Bv, Amsterdam",
journal = "Biochemical Engineering Journal",
title = "Structural changes of Ca-alginate beads caused by immobilized yeast cell growth",
pages = "38-32",
volume = "103",
doi = "10.1016/j.bej.2015.06.016"
}

Pajić-Lijaković, I., Lević, S., Hadnadjev, M., Stevanović-Dajić, Z., Radosević, R., Nedović, V.,& Bugarski, B.. (2015). Structural changes of Ca-alginate beads caused by immobilized yeast cell growth. in Biochemical Engineering Journal
Elsevier Science Bv, Amsterdam., 103, 32-38.
https://doi.org/10.1016/j.bej.2015.06.016

Pajić-Lijaković I, Lević S, Hadnadjev M, Stevanović-Dajić Z, Radosević R, Nedović V, Bugarski B. Structural changes of Ca-alginate beads caused by immobilized yeast cell growth. in Biochemical Engineering Journal. 2015;103:32-38.
doi:10.1016/j.bej.2015.06.016 .

Pajić-Lijaković, Ivana, Lević, Steva, Hadnadjev, Miroslav, Stevanović-Dajić, Zora, Radosević, Radenko, Nedović, Viktor, Bugarski, Branko, "Structural changes of Ca-alginate beads caused by immobilized yeast cell growth" in Biochemical Engineering Journal, 103 (2015):32-38,
https://doi.org/10.1016/j.bej.2015.06.016 . .