1
|
Ondrušková G, Veselý L, Zezula J, Bachler J, Loerting T, Heger D. Using Excimeric Fluorescence to Study How the Cooling Rate Determines the Behavior of Naphthalenes in Freeze-Concentrated Solutions: Vitrification and Crystallization. J Phys Chem B 2020; 124:10556-10566. [PMID: 33156630 DOI: 10.1021/acs.jpcb.0c07817] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We utilized fluorescence spectroscopy to learn about the molecular arrangement of naphthalene (Np) and 1-methylnaphthalene (MeNp) in frozen aqueous solutions. The freezing induces pronounced compound aggregation in the freeze-concentrated solution (FCS) in between the ice grains. The fluorescence spectroscopy revealed prevalent formation of a vitrified solution and minor crystallization of aromatic compounds. The FCS is shown as a specific environment, differing significantly from not only the pure compounds but also the ice surfaces. The results indicate marked disparity between the behavior of the Np and the MeNp; the cooling rate has a major impact on the former but not on the latter. The spectrum of the Np solution frozen at a faster cooling rate (ca 20 K/min) exhibited a temperature-dependent spectral behavior, whereas the spectrum of the solution frozen at a slower rate (ca 2 K/min) did not alter before melting. We interpret the observation through considering the varied composition of the FCS: Fast freezing leads to a higher water content expressed by the plasticizing effect, allowing molecular rearrangement, while slow cooling produces a more concentrated and drier environment. The experiments were conceived as generalizable for environmentally relevant pollutants and human-made freezing.
Collapse
Affiliation(s)
- Gabriela Ondrušková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Lukáš Veselý
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Jan Zezula
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| | - Johannes Bachler
- Institute of Physical Chemistry, University of Innsbruck, Innrine 52c, A-6020 Innsbruck, Austria
| | - Thomas Loerting
- Institute of Physical Chemistry, University of Innsbruck, Innrine 52c, A-6020 Innsbruck, Austria
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic
| |
Collapse
|
2
|
Imrichová K, Veselý L, Gasser TM, Loerting T, Neděla V, Heger D. Vitrification and increase of basicity in between ice Ihcrystals in rapidly frozen dilute NaCl aqueous solutions. J Chem Phys 2019; 151:014503. [DOI: 10.1063/1.5100852] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Kamila Imrichová
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
- Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, 61264 Brno, Czech Republic
| | - Lukáš Veselý
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| | - Tobias M. Gasser
- Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Thomas Loerting
- Institute of Physical Chemistry, University of Innsbruck, A-6020 Innsbruck, Austria
| | - Vilém Neděla
- Institute of Scientific Instruments of the ASCR, v.v.i., Královopolská 147, 61264 Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, 62500 Brno, Czech Republic
| |
Collapse
|
3
|
Comparing the acidities of aqueous, frozen, and freeze-dried phosphate buffers: Is there a “pH memory” effect? Int J Pharm 2017; 530:316-325. [DOI: 10.1016/j.ijpharm.2017.08.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Revised: 07/25/2017] [Accepted: 08/01/2017] [Indexed: 11/20/2022]
|
4
|
Malongwe JK, Nachtigallová D, Corrochano P, Klán P. Spectroscopic Properties of Anisole at the Air-Ice Interface: A Combined Experimental-Computational Approach. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:5755-5764. [PMID: 27243785 DOI: 10.1021/acs.langmuir.6b01187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A combined experimental and computational approach was used to investigate the spectroscopic properties of anisole in aqueous solutions and at the ice-air interface in the temperature range of 77-298 K. The absorption, diffuse reflectance, and emission spectra of ice samples containing anisole prepared by different techniques, such as slow freezing (frozen aqueous solutions), shock freezing (ice grains), or anisole vapor deposition on ice grains, were measured to evaluate changes in the contaminated ice matrix that occur at different temperatures. It was found that the position of the lowest absorption band of anisole and its tail shift bathochromically by ∼4 nm in frozen samples compared to liquid aqueous solutions. On the other hand, the emission spectra of aqueous anisole solutions were found to fundamentally change upon freezing. While one emission band (∼290 nm) was observed under all circumstances, the second band at ∼350 nm, assigned to an anisole excimer, appeared only at certain temperatures (150-250 K). Its disappearance at lower temperatures is attributed to the formation of crystalline anisole on the ice surface. DFT and ADC(2) calculations were used to interpret the absorption and emission spectra of anisole monomer and dimer associates. Various stable arrangements of the anisole associates were found at the disordered water-air interface in the ground and excited states, but only those with a substantial overlap of the aromatic rings are manifested by the emission band at ∼350 nm.
Collapse
Affiliation(s)
| | - Dana Nachtigallová
- Institute of Organic Chemistry and Biochemistry, Flemingovo nam. 2, 166 10 Prague, Czech Republic
| | | | | |
Collapse
|
5
|
Krausková Ľ, Procházková J, Klašková M, Filipová L, Chaloupková R, Malý S, Damborský J, Heger D. Suppression of protein inactivation during freezing by minimizing pH changes using ionic cryoprotectants. Int J Pharm 2016; 509:41-49. [PMID: 27224008 DOI: 10.1016/j.ijpharm.2016.05.031] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 05/09/2016] [Accepted: 05/16/2016] [Indexed: 11/26/2022]
Abstract
Freezing and lyophilization are often used for stabilization of biomolecules; however, this sometimes results in partial degradation and loss of biological function in these molecules. In this study we examined the effect of freezing-induced acidity changes on denaturation of the model enzyme haloalkane dehalogenase under various experimental conditions. The effective local pH of frozen solutions is shown to be the key causal factor in protein stability. To preserve the activity of frozen-thawed enzymes, acidity changes were prevented by the addition of an ionic cryoprotectant, a compound which counteracts pH changes during freezing due to selective incorporation of its ions into the ice. This approach resulted in complete recovery of enzyme activity after multiple freeze-thaw cycles. We propose the utilization of ionic cryoprotectants as a new and effective cryopreservation method in research laboratories as well as in industrial processes.
Collapse
Affiliation(s)
- Ľubica Krausková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic
| | - Jitka Procházková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic
| | - Martina Klašková
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic
| | - Lenka Filipová
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic
| | - Radka Chaloupková
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic
| | - Stanislav Malý
- Central Institute for Supervising and Testing in Agriculture, Hroznová 2, CZ-656 06, Czech Republic
| | - Jiří Damborský
- Loschmidt Laboratories, Department of Experimental Biology, Faculty of Science, Masaryk University, Kamenice 5/A13, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic
| | - Dominik Heger
- Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5/A8, 625 00 Brno, Czech Republic; Research Centre for Toxic Compounds in the Environment RECETOX, Faculty of Science, Masaryk University, Kamenice 5/A29, 625 00 Brno, Czech Republic.
| |
Collapse
|