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Dorchei F, Heydari A, Kroneková Z, Kronek J, Pelach M, Cseriová Z, Chorvát D, Zúñiga-Navarrete F, Rios PD, McGarrigle J, Ghani S, Isa D, Joshi I, Vasuthas K, Rokstad AMA, Oberholzer J, Raus V, Lacík I. Postmodification with Polycations Enhances Key Properties of Alginate-Based Multicomponent Microcapsules. Biomacromolecules 2024; 25:4118-4138. [PMID: 38857534 DOI: 10.1021/acs.biomac.4c00222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2024]
Abstract
Postmodification of alginate-based microspheres with polyelectrolytes (PEs) is commonly used in the cell encapsulation field to control microsphere stability and permeability. However, little is known about how different applied PEs shape the microsphere morphology and properties, particularly in vivo. Here, we addressed this question using model multicomponent alginate-based microcapsules postmodified with PEs of different charge and structure. We found that the postmodification can enhance or impair the mechanical resistance and biocompatibility of microcapsules implanted into a mouse model, with polycations surprisingly providing the best results. Confocal Raman microscopy and confocal laser scanning microscopy (CLSM) analyses revealed stable interpolyelectrolyte complex layers within the parent microcapsule, hindering the access of higher molar weight PEs into the microcapsule core. All microcapsules showed negative surface zeta potential, indicating that the postmodification PEs get hidden within the microcapsule membrane, which agrees with CLSM data. Human whole blood assay revealed complex behavior of microcapsules regarding their inflammatory and coagulation potential. Importantly, most of the postmodification PEs, including polycations, were found to be benign toward the encapsulated model cells.
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Affiliation(s)
- Faeze Dorchei
- Department for Biomaterials Research, Polymer Institute of the Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava, Slovakia
| | - Abolfazl Heydari
- Department for Biomaterials Research, Polymer Institute of the Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava, Slovakia
- National Institute of Rheumatic Diseases, Nábrežie I. Krasku 4, 921 12 Piešt'any, Slovakia
| | - Zuzana Kroneková
- Department for Biomaterials Research, Polymer Institute of the Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava, Slovakia
- National Institute of Rheumatic Diseases, Nábrežie I. Krasku 4, 921 12 Piešt'any, Slovakia
| | - Juraj Kronek
- Department for Biomaterials Research, Polymer Institute of the Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava, Slovakia
- National Institute of Rheumatic Diseases, Nábrežie I. Krasku 4, 921 12 Piešt'any, Slovakia
| | - Michal Pelach
- Department for Biomaterials Research, Polymer Institute of the Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava, Slovakia
| | - Zuzana Cseriová
- Department for Biomaterials Research, Polymer Institute of the Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava, Slovakia
| | - Dušan Chorvát
- Department of Biophotonics, International Laser Centre, Slovak Centre of Scientific and Technical Information, Ilkovičova 3, 841 04 Bratislava, Slovakia
| | - Fernando Zúñiga-Navarrete
- Department of Proteomics, Institute of Virology, Biomedical Research Center of the Slovak Academy of Sciences, Dúbravská cesta 9, 845 05 Bratislava, Slovakia
| | - Peter D Rios
- CellTrans, Inc., 2201 W. Campbell Park Dr., Chicago, Illinois 60612, United States
| | - James McGarrigle
- CellTrans, Inc., 2201 W. Campbell Park Dr., Chicago, Illinois 60612, United States
| | - Sofia Ghani
- CellTrans, Inc., 2201 W. Campbell Park Dr., Chicago, Illinois 60612, United States
| | - Douglas Isa
- CellTrans, Inc., 2201 W. Campbell Park Dr., Chicago, Illinois 60612, United States
| | - Ira Joshi
- CellTrans, Inc., 2201 W. Campbell Park Dr., Chicago, Illinois 60612, United States
| | - Kalaiyarasi Vasuthas
- Centre of Molecular Inflammation Research (CEMIR), Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Prinsesse Kristinas gt.1, NO-7491 Trondheim, Norway
| | - Anne Mari A Rokstad
- Centre of Molecular Inflammation Research (CEMIR), Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Prinsesse Kristinas gt.1, NO-7491 Trondheim, Norway
| | - José Oberholzer
- CellTrans, Inc., 2201 W. Campbell Park Dr., Chicago, Illinois 60612, United States
- Department of Visceral Surgery and Transplantation, University Hospital Zurich, Raemistrasse 100, 8091 Zurich, Switzerland
| | - Vladimír Raus
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského nám. 2, 162 06 Prague 6, Czech Republic
| | - Igor Lacík
- Department for Biomaterials Research, Polymer Institute of the Slovak Academy of Sciences, Dúbravská cesta 9, 845 41 Bratislava, Slovakia
- National Institute of Rheumatic Diseases, Nábrežie I. Krasku 4, 921 12 Piešt'any, Slovakia
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Šabacká P, Maxa J, Švecová J, Talár J, Binar T, Bayer R, Bača P, Dostalová P, Švarc J. Mathematical-Physics Analyses of the Nozzle Shaping at the Aperture Gas Outlet into Free Space under ESEM Pressure Conditions. SENSORS (BASEL, SWITZERLAND) 2024; 24:3436. [PMID: 38894227 PMCID: PMC11174927 DOI: 10.3390/s24113436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2024] [Revised: 05/15/2024] [Accepted: 05/23/2024] [Indexed: 06/21/2024]
Abstract
The paper presents a methodology that combines experimental measurements and mathematical-physics analyses to investigate the flow behavior in a nozzle-equipped aperture associated with the solution of its impact on electron beam dispersion in an environmental scanning electron microscope (ESEM). The shape of the nozzle significantly influences the character of the supersonic flow beyond the aperture, especially the shape and type of shock waves, which are highly dense compared to the surrounding gas. These significantly affect the electron scattering, which influences the resulting image. This paper analyzes the effect of aperture and nozzle shaping under specific low-pressure conditions and its impact on the electron dispersion of the primary electron beam.
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Affiliation(s)
- Pavla Šabacká
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (T.B.); (R.B.); (P.D.)
- Institute of Scientific Instruments of the CAS, Královopolská 147, 612 64 Brno, Czech Republic
| | - Jiří Maxa
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (T.B.); (R.B.); (P.D.)
- Institute of Scientific Instruments of the CAS, Královopolská 147, 612 64 Brno, Czech Republic
| | - Jana Švecová
- Faculty of Military Leadership, University of Defence, 662 10 Brno, Czech Republic; (J.Š.); (J.Š.)
| | - Jaroslav Talár
- Faculty of Military Leadership, University of Defence, 662 10 Brno, Czech Republic; (J.Š.); (J.Š.)
| | - Tomáš Binar
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (T.B.); (R.B.); (P.D.)
| | - Robert Bayer
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (T.B.); (R.B.); (P.D.)
| | - Petr Bača
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (T.B.); (R.B.); (P.D.)
| | - Petra Dostalová
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (T.B.); (R.B.); (P.D.)
| | - Jiří Švarc
- Faculty of Military Leadership, University of Defence, 662 10 Brno, Czech Republic; (J.Š.); (J.Š.)
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Maxa J, Šabacká P, Mazal J, Neděla V, Binar T, Bača P, Talár J, Bayer R, Čudek P. The Impact of Nozzle Opening Thickness on Flow Characteristics and Primary Electron Beam Scattering in an Environmental Scanning Electron Microscope. SENSORS (BASEL, SWITZERLAND) 2024; 24:2166. [PMID: 38610377 PMCID: PMC11014117 DOI: 10.3390/s24072166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/13/2024] [Accepted: 03/26/2024] [Indexed: 04/14/2024]
Abstract
This paper describes the methodology of combining experimental measurements with mathematical-physics analyses in the investigation of flow in the aperture and nozzle. The aperture and nozzle separate the differentially pumped chamber from the specimen chamber in an environmental scanning electron microscope (ESEM). Experimental measurements are provided by temperature and pressure sensors that meet the demanding conditions of cryogenic temperature zones and low pressures. This aperture maintains the required pressure difference between the chambers. Since it separates the large pressure gradient, critical flow occurs on it and supersonic gas flow with the characteristic properties of critical flow in the state variables occurs behind it. As a primary electron beam passes through the differential pumped chamber and the given aperture, the aperture is equipped with a nozzle. The shape of the nozzle strongly influences the character of the supersonic flow. The course of state variables is also strongly influenced by this shape; thus, it affects the number of collisions the primary beam's electrons have with gas molecules, and so the resulting image. This paper describes experimental measurements made using sensors under laboratory conditions in a specially created experimental chamber. Then, validation using mathematical-physical analysis in the Ansys Fluent system is described.
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Affiliation(s)
- Jiří Maxa
- Institute of Scientific Instruments of the CAS, Královopolská 147, 612 64 Brno, Czech Republic
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.)
| | - Pavla Šabacká
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.)
| | - Jan Mazal
- Faculty of Military Robotics, University of Defence, 662 10 Brno, Czech Republic
| | - Vilém Neděla
- Institute of Scientific Instruments of the CAS, Královopolská 147, 612 64 Brno, Czech Republic
| | - Tomáš Binar
- Faculty of Military Leadership, University of Defence, 662 10 Brno, Czech Republic (J.T.)
| | - Petr Bača
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.)
| | - Jaroslav Talár
- Faculty of Military Leadership, University of Defence, 662 10 Brno, Czech Republic (J.T.)
| | - Robert Bayer
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.)
| | - Pavel Čudek
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.)
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Šabacká P, Maxa J, Bayer R, Binar T, Bača P, Dostalová P, Mačák M, Čudek P. Comparative Analysis of Supersonic Flow in Atmospheric and Low Pressure in the Region of Shock Waves Creation for Electron Microscopy. SENSORS (BASEL, SWITZERLAND) 2023; 23:9765. [PMID: 38139611 PMCID: PMC10747329 DOI: 10.3390/s23249765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023]
Abstract
This paper presents mathematical-physics analyses in the field of the influence of inserted sensors on the supersonic flow behind the nozzle. It evaluates differences in the flow in the area of atmospheric pressure and low pressure on the boundary of continuum mechanics. To analyze the formation of detached and conical shock waves and their distinct characteristics in atmospheric pressure and low pressure on the boundary of continuum mechanics, we conduct comparative analyses using two types of inserted sensors: flat end and tip. These analyses were performed in two variants, considering pressure ratios of 10:1 both in front of and behind the nozzle. The first variant involved using atmospheric pressure in the chamber in front of the nozzle. The second type of analysis was conducted with a pressure of 10,000 Pa in front of the nozzle. While this represents a low pressure at the boundary of continuum mechanics, it remains above the critical limit of 113 Pa. This deliberate choice was made as it falls within the team's research focus on low-pressure regions. Although it is situated at the boundary of continuum mechanics, it is intentionally within a pressure range where the viscosity values are not yet dependent on pressure. In these variants, the nature of the flow was investigated concerning the ratio of inertial and viscous flow forces under atmospheric pressure conditions, and it was compared with flow conditions at low pressure. In the low-pressure scenario, the ratio of inertial and viscous flow forces led to a significant reduction in the value of inertial forces. The results showed an altered flow character, characterized by a reduced tendency for the formation of cross-oblique shockwaves within the nozzle itself and the emergence of shockwaves with increased thickness. This increased thickness is attributed to viscous forces inhibiting the thickening of the shockwave itself. This altered flow character may have implications, such as influencing temperature sensing with a tipped sensor. The shockwave area may form in a very confined space in front of the tip, potentially impacting the results. Additionally, due to reduced inertial forces, the cone shock wave's angle is a few degrees larger than theoretical predictions, and there is no tilting due to lower inertial forces. These analyses serve as the basis for upcoming experiments in the experimental chamber designed specifically for investigations in the given region of low pressures at the boundary of continuum mechanics. The objective, in combination with mathematical-physics analyses, is to determine changes within this region of the continuum mechanics boundary where inertial forces are markedly lower than in the atmosphere but remain under the influence of unreduced viscosity.
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Affiliation(s)
- Pavla Šabacká
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.); (T.B.); (P.B.); (P.D.)
| | - Jiří Maxa
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.); (T.B.); (P.B.); (P.D.)
- Institute of Scientific Instruments of the CAS, Královopolská 147, 612 64 Brno, Czech Republic
| | - Robert Bayer
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.); (T.B.); (P.B.); (P.D.)
| | - Tomáš Binar
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.); (T.B.); (P.B.); (P.D.)
| | - Petr Bača
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.); (T.B.); (P.B.); (P.D.)
| | - Petra Dostalová
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.); (T.B.); (P.B.); (P.D.)
| | - Martin Mačák
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.); (T.B.); (P.B.); (P.D.)
| | - Pavel Čudek
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic (R.B.); (T.B.); (P.B.); (P.D.)
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Maxa J, Neděla V, Šabacká P, Binar T. Impact of Supersonic Flow in Scintillator Detector Apertures on the Resulting Pumping Effect of the Vacuum Chambers. SENSORS (BASEL, SWITZERLAND) 2023; 23:4861. [PMID: 37430777 DOI: 10.3390/s23104861] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/26/2023] [Accepted: 05/16/2023] [Indexed: 07/12/2023]
Abstract
The article describes the combination of experimental measurements with mathematical-physics analyses in flow investigation in the chambers of the scintillator detector, which is a part of the environmental scanning electron microscope. The chambers are divided with apertures by small openings that keep the desirable pressure differences between three chambers: The specimen chamber, the differentially pumped intermediate chamber, and the scintillator chamber. There are conflicting demands on these apertures. On the one hand, the diameter of the apertures must be as big as possible so that they incur minimal losses of the passing secondary electrons. On the other hand, it is possible to magnify the apertures only to a certain extent so the rotary and turbomolecular vacuum pump can maintain the required operating pressures in separate chambers. The article describes the combination of experimental measurement using an absolute pressure sensor and mathematical physics analysis to map all the specifics of the emerging critical supersonic flow in apertures between the chambers. Based on the experiments and their tuned analyses, the most effective variant of combining the sizes of each aperture concerning different operating pressures in the detector is determined. The situation is made more difficult by the described fact that each aperture separates a different pressure gradient, so the gas flow through each aperture has its own characteristics with a different type of critical flow, and they influence each other, thereby influencing the final passage of secondary electrons detected by the scintillator and thus affecting the resulting displayed image.
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Affiliation(s)
- Jiří Maxa
- Institute of Scientific Instruments of the CAS, Královopolská 147, 612 64 Brno, Czech Republic
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic
| | - Vilém Neděla
- Institute of Scientific Instruments of the CAS, Královopolská 147, 612 64 Brno, Czech Republic
| | - Pavla Šabacká
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic
| | - Tomáš Binar
- Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 10, 616 00 Brno, Czech Republic
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Chemo-Enzymatic Production of 4-Nitrophenyl-2-acetamido-2-deoxy-α-D-galactopyranoside Using Immobilized β-N-Acetylhexosaminidase. Catalysts 2022. [DOI: 10.3390/catal12050474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
α-Nitrophenyl derivatives of glycosides are convenient substrates used to detect and characterize α-N-acetylgalactosaminidase. A new procedure combining chemical and biocatalytic steps was developed to prepare 4-nitrophenyl-2-acetamido-2-deoxy-α-D-galactopyranoside (4NP-α-GalNAc). The α-anomer was prepared through chemical synthesis of an anomeric mixture followed by selective removal of the β-anomer using specific enzymatic hydrolysis. Fungal β-N-acetylhexosaminidase (Hex) from Penicillium oxalicum CCF 1959 served this purpose owing to its high chemo-and regioselectivity towards the β-anomeric N-acetylgalactosamine (GalNAc) derivative. The kinetic measurements of the hydrolytic reaction showed that the enzyme was not inhibited by the substrate or reaction products. The immobilization of Hex in lens-shaped polyvinyl alcohol hydrogel capsules provided a biocatalyst with very good storage and operational stability. The immobilized Hex retained 97% of the initial activity after ten repeated uses and 90% of the initial activity after 18 months of storage at 4 °C. Immobilization inactivated 65% of the enzyme activity. However, the effectiveness factor and kinetic and mass transfer phenomena approached unity indicating negligible mass transfer limitations.
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Šabacká P, Neděla V, Maxa J, Bayer R. Application of Prandtl's Theory in the Design of an Experimental Chamber for Static Pressure Measurements. SENSORS 2021; 21:s21206849. [PMID: 34696062 PMCID: PMC8538980 DOI: 10.3390/s21206849] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 11/16/2022]
Abstract
Pumping in vacuum chambers is part of the field of environmental electron microscopy. These chambers are separated from each other by a small-diameter aperture that creates a critical flow in the supersonic flow regime. The distribution of pressure and shock waves in the path of the primary electron beam passing through the differentially pumped chamber has a large influence on the quality of the resulting microscope image. As part of this research, an experimental chamber was constructed to map supersonic flow at low pressures. The shape of this chamber was designed using mathematical–physical analyses, which served not only as a basis for the design of its geometry, but especially for the correct choice of absolute and differential pressure sensors with respect to the cryogenic temperature generated in the supersonic flow. The mathematical and physical analyses presented here map the nature of the supersonic flow with large gradients of state variables at low pressures at the continuum mechanics boundary near the region of free molecule motion in which the Environmental Electron Microscope and its differentially pumped chamber operate, which has a significant impact on the resulting sharpness of the final image obtained by the microscope. The results of this work map the flow in and behind the Laval nozzle in the experimental chamber and are the initial basis that enabled the optimization of the design of the chamber based on Prandtl’s theory for the possibility of fitting it with pressure probes in such a way that they can map the flow in and behind the Laval nozzle.
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Affiliation(s)
- Pavla Šabacká
- Institute of Scientific Instruments of the CAS, 61264 Brno, Czech Republic; (P.Š.); (V.N.)
- Department of Electrical and Electronic Technology, Brno University of Technology, 61100 Brno, Czech Republic;
| | - Vilém Neděla
- Institute of Scientific Instruments of the CAS, 61264 Brno, Czech Republic; (P.Š.); (V.N.)
| | - Jiří Maxa
- Institute of Scientific Instruments of the CAS, 61264 Brno, Czech Republic; (P.Š.); (V.N.)
- Department of Electrical and Electronic Technology, Brno University of Technology, 61100 Brno, Czech Republic;
- Correspondence:
| | - Robert Bayer
- Department of Electrical and Electronic Technology, Brno University of Technology, 61100 Brno, Czech Republic;
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Immobilized Cell Physiology Imaging and Stabilization of Enzyme Cascade Reaction Using Recombinant Cells Escherichia coli Entrapped in Polyelectrolyte Complex Beads by Jet Break-Up Encapsulator. Catalysts 2020. [DOI: 10.3390/catal10111288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
A novel, high performance, and scalable immobilization protocol using a laminar jet break-up technique was developed for the production of polyelectrolyte complex beads with entrapped viable Escherichia coli cells expressing an enzyme cascade of alcohol dehydrogenase, enoate reductase, and cyclohexanone monooxygenase. A significant improvement of operational stability was achieved by cell immobilization, which was manifested as an almost two-fold higher summative product yield of 63% after five cascade reaction cycles as compared to the yield using free cells of 36% after the maximum achievable number of three cycles. Correspondingly, increased metabolic activity was observed by multimodal optical imaging in entrapped cells, which was in contrast to a complete suppression of cell metabolism in free cells after five reaction cycles. Additionally, a high density of cells entrapped in beads had a negligible effect on bead permeability for low molecular weight substrates and products of cascade reaction.
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Vetráková Ľ, Neděla V, Runštuk J, Tihlaříková E, Heger D, Shalaev E. Dynamical in-situ observation of the lyophilization and vacuum-drying processes of a model biopharmaceutical system by an environmental scanning electron microscope. Int J Pharm 2020; 585:119448. [PMID: 32461002 DOI: 10.1016/j.ijpharm.2020.119448] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 04/23/2020] [Accepted: 05/18/2020] [Indexed: 01/22/2023]
Abstract
The paper discusses the real-time monitoring of the changing sample morphology during the entire lyophilization (freeze-drying) and vacuum-drying processes of model biopharmaceutical solutions by using an environmental scanning electron microscope (ESEM); the device's micromanipulators were used to study the interior of the samples in-situ without exposing the samples to atmospheric water vapor. The individual collapse temperatures (Tc) of the formulations, pure bovine serum albumin (BSA) and BSA/sucrose mixtures, ranged from -5 to -29 °C. We evaluated the impact of the freezing method (spontaneous freezing, controlled ice nucleation, and spray freezing) on the morphologies of the lyophiles at the constant drying temperature of -20 °C. The formulations with Tc above -20 °C resulted in the lyophiles' morphologies significantly dependent on the freezing method. We interpret the observations as an interplay of the freezing rates and directionalities, both of which markedly influence the morphologies of the frozen formulations, and, subsequently, the drying process and the mechanical stability of the freeze-dried cake. The formulation with Tc below -20 °C yielded a collapsed cake with features independent of the freezing method. The vacuum-drying produced a material with a smooth and pore-free surface, where deep cracks developed at the end of the process.
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Affiliation(s)
- Ľubica Vetráková
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic.
| | - Vilém Neděla
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Jiří Runštuk
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Eva Tihlaříková
- Environmental Electron Microscopy Group, Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic.
| | - Evgenyi Shalaev
- Pharmaceutical Development, Allergan plc, Irvine, CA, United States.
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Neděla V, Tihlaříková E, Maxa J, Imrichová K, Bučko M, Gemeiner P. Simulation-based optimisation of thermodynamic conditions in the ESEM for dynamical in-situ study of spherical polyelectrolyte complex particles in their native state. Ultramicroscopy 2020; 211:112954. [PMID: 32018072 DOI: 10.1016/j.ultramic.2020.112954] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/23/2020] [Accepted: 01/26/2020] [Indexed: 11/18/2022]
Abstract
We present a complex analysis and optimisation of dynamic conditions in the environmental scanning electron microscope (ESEM) to allow in-situ observation of extremely delicate wet bio-polymeric spherical particles in their native state. According to the results of gas flow and heat transfer simulations, we were able to develop an improved procedure leading to thermodynamic equilibrium between the sample and chamber environment. To quantify and hence minimise the extent of any sample deformation during specimen chamber pumping, a strength-stress analysis is used. Monte Carlo simulations of beam-gas, -water, and -sample interactions describe beam scattering, absorbed energy, interaction volume and the emission of signal electrons in the ESEM. Finally, we discuss sample damage as a result of drying and the production of beam-induced free radicals. Based on all experimental and simulation results we introduce a Delicate Sample Observation Strategy for the ESEM. We show how this strategy can be applied to the characterization of polyelectrolyte complex spherical particles containing immobilized recombinant cells E. coli overexpressing cyclohexanone monooxygenase, used as a model biocatalyst. We present the first native-state electron microscopy images of the viscous core of a halved polyelectrolyte complex capsule containing living cells.
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Affiliation(s)
- Vilém Neděla
- Environmental electron microscopy group, Institute of Scientific Instruments of ASCR, Královopolská 147, 61264 Brno, Czech Republic.
| | - Eva Tihlaříková
- Environmental electron microscopy group, Institute of Scientific Instruments of ASCR, Královopolská 147, 61264 Brno, Czech Republic
| | - Jiří Maxa
- Environmental electron microscopy group, Institute of Scientific Instruments of ASCR, Královopolská 147, 61264 Brno, Czech Republic
| | - Kamila Imrichová
- Environmental electron microscopy group, Institute of Scientific Instruments of ASCR, Královopolská 147, 61264 Brno, Czech Republic
| | - Marek Bučko
- Institute of Chemistry, Centre for Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 84538 Bratislava, Slovakia
| | - Peter Gemeiner
- Institute of Chemistry, Centre for Glycomics, Slovak Academy of Sciences, Dúbravská cesta 9, 84538 Bratislava, Slovakia
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Tihlaříková E, Neděla V, Đorđević B. In-situ preparation of plant samples in ESEM for energy dispersive x-ray microanalysis and repetitive observation in SEM and ESEM. Sci Rep 2019; 9:2300. [PMID: 30783188 PMCID: PMC6381206 DOI: 10.1038/s41598-019-38835-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 01/07/2019] [Indexed: 11/25/2022] Open
Abstract
The Extended Low Temperature Method (ELTM) for the in-situ preparation of plant samples in an environmental scanning electron microscope enables carrying out repetitive topographical and material analysis at a higher resolution in the vacuum conditions of a scanning electron microscope or in the low gas pressure conditions of an environmental scanning electron microscope. The method does not require any chemical intervention and is thus suitable for imaging delicate structures rarely observable with common treatment methods. The method enables both sample stabilization as close to their native state as possible, as well as the transfer of the same sample from a low vacuum to an atmospheric condition for sample storage or later study. It is impossible for wet samples in the environmental scanning electron microscope. Our studies illustrate the high applicability of the ELTM for different types of plant tissue, from imaging of plant waxes at higher resolution, the morphological study of highly susceptible early somatic embryos to the elemental microanalysis of root cells. The method established here provides a very fast, universal and inexpensive solution for plant sample treatment usable in a commercial environmental scanning electron microscope equipped with a cooling Peltier stage.
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Affiliation(s)
- Eva Tihlaříková
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, 612 00, Czech Republic.
| | - Vilém Neděla
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, 612 00, Czech Republic
| | - Biljana Đorđević
- Department of Plant Biology, Mendel University in Brno, Brno, 613 00, Czech Republic
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12
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Eliášová K, Vondráková Z, Gemperlová L, Neděla V, Runštuk J, Fischerová L, Malbeck J, Trávníčková A, Cvikrová M, Vágner M. The Response of Picea abies Somatic Embryos to UV-B Radiation Depends on the Phase of Maturation. FRONTIERS IN PLANT SCIENCE 2018; 9:1736. [PMID: 30538715 PMCID: PMC6277568 DOI: 10.3389/fpls.2018.01736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 11/08/2018] [Indexed: 06/09/2023]
Abstract
Ultraviolet-B (UV-B) radiation is a key environmental signal which initiates diverse responses that affect the metabolism, development, and viability of plants. In keeping with our previous studies, we concentrated primarily on how UV-B radiation affects Norway spruce [Picea abies (L.) Karst.] somatic embryo maturation and how phenolics and polyamines (PAs) are linked to the defense response invoked by UV-B irradiation. We treated clusters of Norway spruce embryogenic culture (EC) with UV-B during the five stages of embryo maturation (early, cylindrical, precotyledonary, cotyledonary, and mature embryos). For the first time, we take an advantage of the unique environmental scanning electron microscope AQUASEM II to characterize somatic embryos in their native state. The severity of the irradiation effect on embryonal cell viability was shown to be dependent on the intensity of radiation as well as the stage of embryo development, and might be related to the formation of protoderm. The response of early embryos was characterized by an increase in malondialdehyde (MDA), a marked decrease in PA contents and a decline in phenolics. The reduced ability to activate the defense system seems to be responsible not only for the severe cell damage and decrease in viability but also for the inhibition of embryo development. The significant reduction in spermidine (Spd), which has been reported to be crucial for the somatic embryo development of several coniferous species, may be causally linked to the limited development of embryos. The pronounced decrease in cell wall-bound ferulic acid might correspond to failure of somatic embryos to reach more advanced stages of development. Embryos at later stages of development showed stress defense responses that were more efficient against UV-B exposure.
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Affiliation(s)
- Kateřina Eliášová
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Zuzana Vondráková
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Lenka Gemperlová
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Vilém Neděla
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czechia
| | - Jiří Runštuk
- Institute of Scientific Instruments of the Czech Academy of Sciences, Brno, Czechia
| | - Lucie Fischerová
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Jiří Malbeck
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Alena Trávníčková
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Milena Cvikrová
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Martin Vágner
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
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Kecskemeti A, Gaspar A. Particle-based immobilized enzymatic reactors in microfluidic chips. Talanta 2018; 180:211-228. [DOI: 10.1016/j.talanta.2017.12.043] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 12/13/2017] [Indexed: 10/18/2022]
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14
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Effect of the preparation of lime putties on their properties. Sci Rep 2017; 7:17260. [PMID: 29222495 PMCID: PMC5722907 DOI: 10.1038/s41598-017-17527-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/27/2017] [Indexed: 11/08/2022] Open
Abstract
In the study of lime as the basic component of historical mortars and plasters, four lime putties prepared from various kinds of lime of various granulometry and by various ways of preparation were evaluated. The rheological properties and micro-morphologic changes, growing of calcite crystals, and rate of carbonation were monitored. The lime putty prepared from lump lime achieves the best rheological properties, yield stress 214.7 Pa and plastic viscosity 2.6 Pa·s. The suitability of this lime putty was checked by testing the development of calcium hydroxide and calcite crystals using scanning electron microscopy and environmental scanning electron microscopy. The disordered crystals of calcium hydroxide exhibit better carbonation resulting in the large crystals of calcite; therefore, the mortar prepared from the lump lime has the highest flexural strength and compressive strength 0.8/2.5 MPa, its carbonation is the fastest and exhibits the longest durability. Also, thanks to the micro-morphological characterization of samples in their native state by means of environmental scanning electron microscopy, the new way of lime putty preparation by mixing was proven. The preparation consists in the mechanical crash of the lime particles immediately after hydration. This enables the properties of putty prepared from lump lime to be nearly reached.
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Polyelectrolyte Complex Beads by Novel Two-Step Process for Improved Performance of Viable Whole-Cell Baeyer-Villiger Monoxygenase by Immobilization. Catalysts 2017. [DOI: 10.3390/catal7110353] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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16
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Progress in emerging techniques for characterization of immobilized viable whole-cell biocatalysts. CHEMICAL PAPERS 2017. [DOI: 10.1007/s11696-017-0243-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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17
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Polakovič M, Švitel J, Bučko M, Filip J, Neděla V, Ansorge-Schumacher MB, Gemeiner P. Progress in biocatalysis with immobilized viable whole cells: systems development, reaction engineering and applications. Biotechnol Lett 2017; 39:667-683. [PMID: 28181062 DOI: 10.1007/s10529-017-2300-y] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 02/01/2017] [Indexed: 11/28/2022]
Abstract
Viable microbial cells are important biocatalysts in the production of fine chemicals and biofuels, in environmental applications and also in emerging applications such as biosensors or medicine. Their increasing significance is driven mainly by the intensive development of high performance recombinant strains supplying multienzyme cascade reaction pathways, and by advances in preservation of the native state and stability of whole-cell biocatalysts throughout their application. In many cases, the stability and performance of whole-cell biocatalysts can be highly improved by controlled immobilization techniques. This review summarizes the current progress in the development of immobilized whole-cell biocatalysts, the immobilization methods as well as in the bioreaction engineering aspects and economical aspects of their biocatalytic applications.
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Affiliation(s)
- Milan Polakovič
- Institute of Chemical and Environmental Engineering, Faculty of Chemical and Food Technology, Slovak Technical University, Bratislava, Slovakia
| | - Juraj Švitel
- Institute of Chemical and Environmental Engineering, Faculty of Chemical and Food Technology, Slovak Technical University, Bratislava, Slovakia
| | - Marek Bučko
- Department of Glycobiotechnology, Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jaroslav Filip
- Center for Advanced Materials, Qatar University, Doha, Qatar
| | - Vilém Neděla
- Institute of Scientific Instruments, Academy of Sciences Czech Republic, Brno, Czech Republic
| | | | - Peter Gemeiner
- Department of Glycobiotechnology, Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovakia.
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Hronská H, Mastihuba V, Tokošová S, Rosenberg M. Semicontinual synthesis of alkyl galactosides using β-galactosidase entrapped in polyvinylalcohol hydrogel. BIOCATAL BIOTRANSFOR 2016. [DOI: 10.1080/10242422.2016.1247827] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Helena Hronská
- Faculty of Chemical and Food Technology, Institute of Biotechnology, Slovak University of Technology, Bratislava, Slovak Republic and
| | - Vladimír Mastihuba
- Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Silvia Tokošová
- Faculty of Chemical and Food Technology, Institute of Biotechnology, Slovak University of Technology, Bratislava, Slovak Republic and
| | - Michal Rosenberg
- Faculty of Chemical and Food Technology, Institute of Biotechnology, Slovak University of Technology, Bratislava, Slovak Republic and
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20
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Baeyer-Villiger oxidations: biotechnological approach. Appl Microbiol Biotechnol 2016; 100:6585-6599. [DOI: 10.1007/s00253-016-7670-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 06/02/2016] [Accepted: 06/07/2016] [Indexed: 10/21/2022]
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21
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Wachtmeister J, Rother D. Recent advances in whole cell biocatalysis techniques bridging from investigative to industrial scale. Curr Opin Biotechnol 2016; 42:169-177. [PMID: 27318259 DOI: 10.1016/j.copbio.2016.05.005] [Citation(s) in RCA: 186] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 05/20/2016] [Accepted: 05/21/2016] [Indexed: 11/25/2022]
Abstract
Recent advances in biocatalysis have strongly boosted its recognition as a valuable addition to traditional chemical synthesis routes. As for any catalytic process, catalyst's costs and stabilities are of highest relevance for the economic application in chemical manufacturing. Employing biocatalysts as whole cells circumvents the need of cell lysis and enzyme purification and hence strongly cuts on cost. At the same time, residual cell wall components can shield the entrapped enzyme from potentially harmful surroundings and aid to enable applications far from natural enzymatic environments. Further advantages are the close proximity of reactants and catalysts as well as the inherent presence of expensive cofactors. Here, we review and comment on benefits and recent advances in whole cell biocatalysis.
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Affiliation(s)
| | - Dörte Rother
- IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, 52428 Jülich, Germany.
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22
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Kisukuri CM, Andrade LH. Production of chiral compounds using immobilized cells as a source of biocatalysts. Org Biomol Chem 2015; 13:10086-107. [PMID: 26366634 DOI: 10.1039/c5ob01677k] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The importance of chiral compounds in all fields of technology and life sciences is shown. Small chiral molecules are mainly used as building blocks in the synthesis of more complex and functionalized compounds. Nature creates and imposes stereoselectivity by means of enzymes, which are highly efficient biocatalysts. The use of whole cells as a biocatalyst source is a promising strategy for avoiding some drawbacks associated with the use of pure enzymes, especially their high cost. The use of free cells is also challenging, since cell lysis can also occur under the reaction conditions. However, cell immobilization has been employed to increase the catalytic potential of enzymes by extending their lifetimes in organic solvents and non-natural environments. Besides, immobilized cells maintain their biocatalytic performance for several reaction cycles. Considering the above-mentioned arguments, several authors have synthesized different classes of chiral compounds such as alcohols, amines, carboxylic acids, amides, sulfides and lactones by means of immobilized cells. Our aim was to discuss the main aspects of the production of chiral compounds using immobilized cells as a source of biocatalysts, except under fermentation conditions.
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Affiliation(s)
- Camila M Kisukuri
- Universidade de São Paulo, Instituto de Química, Av. Prof. Lineu Prestes 748, SP 05508-900, São Paulo, Brazil.
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Bertóková A, Vikartovská A, Bučko M, Gemeiner P, Tkáč J, Chorvát D, Štefuca V, Neděla V. Biooxidation of 2-phenylethanol to phenylacetic acid by whole-cellGluconobacter oxydansbiocatalyst immobilized in polyelectrolyte complex capsules. BIOCATAL BIOTRANSFOR 2015. [DOI: 10.3109/10242422.2015.1053470] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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