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Dietrich A, Schiemer R, Kurmann J, Zhang S, Hubbuch J. Raman-based PAT for VLP precipitation: systematic data diversification and preprocessing pipeline identification. Front Bioeng Biotechnol 2024; 12:1399938. [PMID: 38882637 PMCID: PMC11177211 DOI: 10.3389/fbioe.2024.1399938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 05/13/2024] [Indexed: 06/18/2024] Open
Abstract
Virus-like particles (VLPs) are a promising class of biopharmaceuticals for vaccines and targeted delivery. Starting from clarified lysate, VLPs are typically captured by selective precipitation. While VLP precipitation is induced by step-wise or continuous precipitant addition, current monitoring approaches do not support the direct product quantification, and analytical methods usually require various, time-consuming processing and sample preparation steps. Here, the application of Raman spectroscopy combined with chemometric methods may allow the simultaneous quantification of the precipitated VLPs and precipitant owing to its demonstrated advantages in analyzing crude, complex mixtures. In this study, we present a Raman spectroscopy-based Process Analytical Technology (PAT) tool developed on batch and fed-batch precipitation experiments of Hepatitis B core Antigen VLPs. We conducted small-scale precipitation experiments providing a diversified data set with varying precipitation dynamics and backgrounds induced by initial dilution or spiking of clarified Escherichia coli-derived lysates. For the Raman spectroscopy data, various preprocessing operations were systematically combined allowing the identification of a preprocessing pipeline, which proved to effectively eliminate initial lysate composition variations as well as most interferences attributed to precipitates and the precipitant present in solution. The calibrated partial least squares models seamlessly predicted the precipitant concentration with R 2 of 0.98 and 0.97 in batch and fed-batch experiments, respectively, and captured the observed precipitation trends with R 2 of 0.74 and 0.64. Although the resolution of fine differences between experiments was limited due to the observed non-linear relationship between spectral data and the VLP concentration, this study provides a foundation for employing Raman spectroscopy as a PAT sensor for monitoring VLP precipitation processes with the potential to extend its applicability to other phase-behavior dependent processes or molecules.
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Affiliation(s)
- Annabelle Dietrich
- Institute of Process Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Robin Schiemer
- Institute of Process Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Jasper Kurmann
- Institute of Process Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Shiqi Zhang
- Institute of Process Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Jürgen Hubbuch
- Institute of Process Engineering in Life Sciences, Section IV: Biomolecular Separation Engineering, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
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2
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Mangini M, Limatola N, Ferrara MA, Coppola G, Chun JT, De Luca AC, Santella L. Application of Raman spectroscopy to the evaluation of F-actin changes in sea urchin eggs at fertilization. ZYGOTE 2024; 32:38-48. [PMID: 38050697 DOI: 10.1017/s0967199423000552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2023]
Abstract
The actin filaments on the surface of echinoderm oocytes and eggs readily undergo massive reorganization during meiotic maturation and fertilization. In sea urchin eggs, the actin cytoskeletal response to the fertilizing sperm is fast enough to accompany Ca2+ signals and to guide sperm's entry into the egg. Although recent work using live cell imaging technology confirmed changes in the actin polymerization status in fertilized eggs, as was previously shown using light and electron microscopy, it failed to provide experimental evidence of F-actin depolymerization a few seconds after insemination, which is concurrent with the sperm-induced Ca2+ release. In the present study, we applied Raman microspectroscopy to tackle this issue by examining the spectral profiles of the egg's subplasmalemmal regions before and after treating the eggs with actin drugs or fertilizing sperm. At both early (15 s) and late (15 min) time points after fertilization, specific peak shifts in the Raman spectra revealed change in the actin structure, and Raman imaging detected the cytoskeletal changes corresponding to the F-actin reorganization visualized with LifeAct-GFP in confocal microscopy. Our observation suggests that the application of Raman spectroscopy, which does not require microinjection of fluorescent probes and exogenous gene expression, may serve as an alternative or even advantageous method in disclosing rapid subtle changes in the subplasmalemmal actin cytoskeleton that are difficult to resolve.
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Affiliation(s)
- Maria Mangini
- Institute of Experimental Endocrinology and Oncology 'G. Salvatore', Second Unit, National Research Council, 80131Naples, Italy
| | - Nunzia Limatola
- Department of Research Infrastructures for Marine Biological Resources, Stazione Zoologica Anton Dohrn, 80121Naples, Italy
| | - Maria Antonietta Ferrara
- Institute of Applied Sciences and Intelligent Systems 'E. Caianiello', Unit of Naples, National Research Council, 80131Naples, Italy
| | - Giuseppe Coppola
- Institute of Applied Sciences and Intelligent Systems 'E. Caianiello', Unit of Naples, National Research Council, 80131Naples, Italy
| | - Jong Tai Chun
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, 80121Naples, Italy
| | - Anna Chiara De Luca
- Institute of Experimental Endocrinology and Oncology 'G. Salvatore', Second Unit, National Research Council, 80131Naples, Italy
| | - Luigia Santella
- Department of Research Infrastructures for Marine Biological Resources, Stazione Zoologica Anton Dohrn, 80121Naples, Italy
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3
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Bolje A, Gobec S. Analytical Techniques for Structural Characterization of Proteins in Solid Pharmaceutical Forms: An Overview. Pharmaceutics 2021; 13:pharmaceutics13040534. [PMID: 33920461 PMCID: PMC8070348 DOI: 10.3390/pharmaceutics13040534] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/21/2021] [Accepted: 04/08/2021] [Indexed: 11/17/2022] Open
Abstract
Therapeutic proteins as biopharmaceuticals have emerged as a very important class of drugs for the treatment of many diseases. However, they are less stable compared to conventional pharmaceuticals. Their long-term stability in solid forms, which is critical for product performance, depends heavily on the retention of the native protein structure during the lyophilization (freeze-drying) process and, thereafter, in the solid state. Indeed, the biological function of proteins is directly related to the tertiary and secondary structure. Besides physical stability and biological activity, conformational stability (three-dimensional structure) is another important aspect when dealing with protein pharmaceuticals. Moreover, denaturation as loss of higher order structure is often a precursor to aggregation or chemical instability. Careful study of the physical and chemical properties of proteins in the dried state is therefore critical during biopharmaceutical drug development to deliver a final drug product with built-in quality that is safe, high-quality, efficient, and affordable for patients. This review provides an overview of common analytical techniques suitable for characterizing pharmaceutical protein powders, providing structural, and conformational information, as well as insights into dynamics. Such information can be very useful in formulation development, where selecting the best formulation for the drug can be quite a challenge.
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Affiliation(s)
- Aljoša Bolje
- Correspondence: (A.B.); (S.G.); Tel.: +386-147-69500 (A.B.); +386-147-69585 (S.G.)
| | - Stanislav Gobec
- Correspondence: (A.B.); (S.G.); Tel.: +386-147-69500 (A.B.); +386-147-69585 (S.G.)
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4
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Nitika N, Chhabra H, Rathore AS. Raman spectroscopy for in situ, real time monitoring of protein aggregation in lyophilized biotherapeutic products. Int J Biol Macromol 2021; 179:309-313. [PMID: 33689770 DOI: 10.1016/j.ijbiomac.2021.02.214] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/19/2021] [Accepted: 02/28/2021] [Indexed: 10/22/2022]
Abstract
Quality of biotherapeutic products is of paramount importance for ensuring patient safety. Analytical tools that can facilitate rapid quality assessment of the therapeutic product at the point of care are very much in demand. In this article, we apply chemometrics based analysis of Raman spectra towards quantitative prediction of protein aggregation in lyophilized biotherapeutic products. Two commercially available therapeutic proteins, erythropoietin (EPO) and human growth hormone (HGH), have been used to demonstrate the applicability of the proposed approach. Thermally induced protein aggregation was monitored by size exclusion chromatography as well as Raman spectroscopy with a 785 nm wavelength laser. Partial least square (PLS) regression was used to analyse the Raman spectra and create a model for quantitative determination of aggregate. Satisfactory performance was observed with both EPO and HGH with R2 of 0.91 and 0.94, cross-validation correlation coefficient of 0.85 and 0.89, and Root Mean Square Error computed from cross calibration (RMSEcv) of 5.25 and 1.92, respectively. The developed approach can enable rapid and accurate assessment of aggregation in lyophilized samples of biotherapeutic products. The study also demonstrates novel use of Raman spectroscopy for protein quantification through a vial.
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Affiliation(s)
- Nitika Nitika
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - Hemlata Chhabra
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India
| | - Anurag S Rathore
- Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India.
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5
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Stephan B, Tittelbach J, Bühler S. Reisevorbereitungen für Patienten mit Psoriasis unter Immunsuppression. J Dtsch Dermatol Ges 2021; 19:197-208. [PMID: 33586903 DOI: 10.1111/ddg.14377_g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/27/2020] [Indexed: 11/28/2022]
Affiliation(s)
- Brigitte Stephan
- Institut für Versorgungsforschung in der Dermatologie und bei Pflegeberufen (IVDP), Universitätsklinikum Hamburg-Eppendorf (UKE), Hamburg
| | | | - Silja Bühler
- Bernhard-Nocht-Institut für Tropenmedizin (BNITM), Hamburg
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6
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Stephan B, Tittelbach J, Bühler S. Considerations for patients with psoriasis travelling under immunosuppression. J Dtsch Dermatol Ges 2021; 19:197-207. [PMID: 33491922 DOI: 10.1111/ddg.14377] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 07/27/2020] [Indexed: 11/29/2022]
Abstract
With the establishment of modern systemic therapies for psoriasis, comprehensive consultation is required for travelling with immune modulation. Logistic aspects regarding transport and storage, climatic peculiarities of the country of travel and drug dependent risks regarding infections must be considered. Vaccinations and preventive measures are emphasized. Depending on the current national recommendations, special features of vaccinations while under immunosuppression must be taken into account.
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Affiliation(s)
- Brigitte Stephan
- Institute for Health Services Research in Dermatology and Nursing (IVDP), University Medical Center Hamburg-Eppendorf (UKE), Hamburg, Germany
| | - Jörg Tittelbach
- Department of Dermatology, University Hospital of Jena, Jena, Germany
| | - Silja Bühler
- Bernhard Nocht Institute for Tropical Medicine (BNITM), Hamburg, Germany
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7
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Hosseini H, Tsau JS, Shafer-Peltier K, Marshall C, Ye Q, Barati Ghahfarokhi R. Experimental and Mechanistic Study of Stabilized Dry CO2 Foam Using Polyelectrolyte Complex Nanoparticles Compatible with Produced Water To Improve Hydraulic Fracturing Performance. Ind Eng Chem Res 2019. [DOI: 10.1021/acs.iecr.9b01390] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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8
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Zhu Y, Li Y, Wu C, Teng F, Qi B, Zhang X, Zhou L, Yu G, Wang H, Zhang S, Wang Z, Jiang L. Stability Mechanism of Two Soybean Protein-Phosphatidylcholine Nanoemulsion Preparation Methods from a Structural Perspective: A Raman Spectroscopy Analysis. Sci Rep 2019; 9:6985. [PMID: 31061497 PMCID: PMC6502802 DOI: 10.1038/s41598-019-43439-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 04/23/2019] [Indexed: 11/17/2022] Open
Abstract
Ultrasound treatment and high-pressure homogenization were used to prepare soybean protein (SP)-phosphatidylcholine (PC) nanoemulsions in this study. Nanoemulsions prepared by high-pressure homogenization were more stable. The structural changes of SP and PC under ultrasound treatment and high-pressure homogenization treatment were investigated by Raman spectroscopy. It could be concluded that ultrasound and high-pressure homogenization treatments increased both the content of α-helix and unordered structure but decreased that of β-structures of SP, while the interaction between SP and PC decreased α-helix content and also reduced unordered structure and β-sheet structure. Ultrasound treatment and high-pressure homogenization exposed more tryptophan and tyrosine residues to promote hydrophobic interaction between SP and PC, which was beneficial for stabilizing the nanoemulsion. The SP-PC interaction exerted a more significant effect on side chain structure than those observed under ultrasound treatment and high-pressure homogenization. The dominant g-g-t vibrational mode of the disulfide bond of soybean protein was not appreciably changed by the two preparations. High-pressure homogenization increased the disorder of lipid chains of PC, promoting SP-PC interaction and thereby increasing the stability of the nanoemulsion. The structural change provided a theoretical basis for preparation of two nanoemulsions.
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Affiliation(s)
- Ying Zhu
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China
| | - Yang Li
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China
- Institute of Food Industry Research in Harbin, Harbin, 150030, China
| | - Changling Wu
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China
| | - Fei Teng
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China
| | - Baokun Qi
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China
| | - Xiaonan Zhang
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China
| | - Linyi Zhou
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China
| | - Guoping Yu
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China
| | - Huan Wang
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China
| | - Shuang Zhang
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China
| | - Zhongjiang Wang
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China.
| | - Lianzhou Jiang
- College of Food Science, Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, China.
- National Research Center of Soybean Engineering and Technology, Harbin, 150030, China.
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9
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Starciuc T, Guinet Y, Paccou L, Hedoux A. Influence of a Small Amount of Glycerol on the Trehalose Bioprotective Action Analyzed In Situ During Freeze-Drying of Lyzozyme Formulations by Micro-Raman Spectroscopy. J Pharm Sci 2017. [DOI: 10.1016/j.xphs.2017.05.040] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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10
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Buckley K, Ryder AG. Applications of Raman Spectroscopy in Biopharmaceutical Manufacturing: A Short Review. APPLIED SPECTROSCOPY 2017; 71:1085-1116. [PMID: 28534676 DOI: 10.1177/0003702817703270] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The production of active pharmaceutical ingredients (APIs) is currently undergoing its biggest transformation in a century. The changes are based on the rapid and dramatic introduction of protein- and macromolecule-based drugs (collectively known as biopharmaceuticals) and can be traced back to the huge investment in biomedical science (in particular in genomics and proteomics) that has been ongoing since the 1970s. Biopharmaceuticals (or biologics) are manufactured using biological-expression systems (such as mammalian, bacterial, insect cells, etc.) and have spawned a large (>€35 billion sales annually in Europe) and growing biopharmaceutical industry (BioPharma). The structural and chemical complexity of biologics, combined with the intricacy of cell-based manufacturing, imposes a huge analytical burden to correctly characterize and quantify both processes (upstream) and products (downstream). In small molecule manufacturing, advances in analytical and computational methods have been extensively exploited to generate process analytical technologies (PAT) that are now used for routine process control, leading to more efficient processes and safer medicines. In the analytical domain, biologic manufacturing is considerably behind and there is both a huge scope and need to produce relevant PAT tools with which to better control processes, and better characterize product macromolecules. Raman spectroscopy, a vibrational spectroscopy with a number of useful properties (nondestructive, non-contact, robustness) has significant potential advantages in BioPharma. Key among them are intrinsically high molecular specificity, the ability to measure in water, the requirement for minimal (or no) sample pre-treatment, the flexibility of sampling configurations, and suitability for automation. Here, we review and discuss a representative selection of the more important Raman applications in BioPharma (with particular emphasis on mammalian cell culture). The review shows that the properties of Raman have been successfully exploited to deliver unique and useful analytical solutions, particularly for online process monitoring. However, it also shows that its inherent susceptibility to fluorescence interference and the weakness of the Raman effect mean that it can never be a panacea. In particular, Raman-based methods are intrinsically limited by the chemical complexity and wide analyte-concentration-profiles of cell culture media/bioprocessing broths which limit their use for quantitative analysis. Nevertheless, with appropriate foreknowledge of these limitations and good experimental design, robust analytical methods can be produced. In addition, new technological developments such as time-resolved detectors, advanced lasers, and plasmonics offer potential of new Raman-based methods to resolve existing limitations and/or provide new analytical insights.
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Affiliation(s)
- Kevin Buckley
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland - Galway, Galway, Ireland
| | - Alan G Ryder
- Nanoscale Biophotonics Laboratory, School of Chemistry, National University of Ireland - Galway, Galway, Ireland
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11
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Ravera E, Martelli T, Geiger Y, Fragai M, Goobes G, Luchinat C. Biosilica and bioinspired silica studied by solid-state NMR. Coord Chem Rev 2016. [DOI: 10.1016/j.ccr.2016.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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12
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Hédoux A. Recent developments in the Raman and infrared investigations of amorphous pharmaceuticals and protein formulations: A review. Adv Drug Deliv Rev 2016; 100:133-46. [PMID: 26686831 DOI: 10.1016/j.addr.2015.11.021] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 11/26/2015] [Accepted: 11/30/2015] [Indexed: 10/22/2022]
Abstract
The success rate for drug discovery and the development of innovative therapeutic strategies are intimately related to the physical properties of the solid-state condensed matter, which have direct influence on the bioavailability of Active Pharmaceutical Ingredients. In order to transform a new molecule in efficient drug, the material is brought into an amorphous state using various manufacturing processes including freeze drying, spray drying, hot melt extrusion and loading in different delivery devices. The infrared and Raman spectroscopic analyses used for exploring disordered and amorphous states, for the monitoring of the drug physical stability in drug delivery systems are described in this review.
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13
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Bolivar JM, Eisl I, Nidetzky B. Advanced characterization of immobilized enzymes as heterogeneous biocatalysts. Catal Today 2016. [DOI: 10.1016/j.cattod.2015.05.004] [Citation(s) in RCA: 129] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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14
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Paudel A, Raijada D, Rantanen J. Raman spectroscopy in pharmaceutical product design. Adv Drug Deliv Rev 2015; 89:3-20. [PMID: 25868453 DOI: 10.1016/j.addr.2015.04.003] [Citation(s) in RCA: 168] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 03/15/2015] [Accepted: 04/01/2015] [Indexed: 12/20/2022]
Abstract
Almost 100 years after the discovery of the Raman scattering phenomenon, related analytical techniques have emerged as important tools in biomedical sciences. Raman spectroscopy and microscopy are frontier, non-invasive analytical techniques amenable for diverse biomedical areas, ranging from molecular-based drug discovery, design of innovative drug delivery systems and quality control of finished products. This review presents concise accounts of various conventional and emerging Raman instrumentations including associated hyphenated tools of pharmaceutical interest. Moreover, relevant application cases of Raman spectroscopy in early and late phase pharmaceutical development, process analysis and micro-structural analysis of drug delivery systems are introduced. Finally, potential areas of future advancement and application of Raman spectroscopic techniques are discussed.
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15
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Bisson PJ, Whitten JE. A compact Raman converter for UV-VIS spectrometers. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:055107. [PMID: 26026558 DOI: 10.1063/1.4921235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A small form factor, easily constructed converter that adapts fiber coupled UV/VIS CCD detector-based spectrometers into a right angle scattering Raman spectrometer is described. Its design philosophy and design are discussed. An example measurement, the depolarization ratio of carbon tetrachloride, a classic Raman test compound, is presented. The unique instrument features a blue-violet (405 nm wavelength) diode laser that takes advantage of the inverse fourth power wavelength dependence of Raman scattering. The converter also features Glan-Thompson polarizing prisms that enable measurement of depolarization ratios. The spectrometer is also capable of measuring a standard Raman spectrum. A fiber optic link offers flexibility when adapting the converter to any spectrometer system that accepts a fiber optic input. The performance of the instrument is critically discussed in the context of an example measurement.
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Affiliation(s)
- Patrick J Bisson
- Department of Chemistry, University of Massachusetts Lowell, Lowell, Massachusetts 01854, USA
| | - James E Whitten
- Department of Chemistry, University of Massachusetts Lowell, Lowell, Massachusetts 01854, USA
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16
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Roessl U, Humi S, Leitgeb S, Nidetzky B. Design of experiments reveals critical parameters for pilot-scale freeze-and-thaw processing of L-lactic dehydrogenase. Biotechnol J 2015; 10:1390-9. [PMID: 25820483 DOI: 10.1002/biot.201400766] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Revised: 02/17/2015] [Accepted: 03/25/2015] [Indexed: 11/09/2022]
Abstract
Freezing constitutes an important unit operation of biotechnological protein production. Effects of freeze-and-thaw (F/T) process parameters on stability and other quality attributes of the protein product are usually not well understood. Here a design of experiments (DoE) approach was used to characterize the F/T behavior of L-lactic dehydrogenase (LDH) in a 700-mL pilot-scale freeze container equipped with internal temperature and pH probes. In 24-hour experiments, target temperature between -10 and -38°C most strongly affected LDH stability whereby enzyme activity was retained best at the highest temperature of -10°C. Cooling profile and liquid fill volume also had significant effects on LDH stability and affected the protein aggregation significantly. Parameters of the thawing phase had a comparably small effect on LDH stability. Experiments in which the standard sodium phosphate buffer was exchanged by Tris-HCl and the non-ionic surfactant Tween 80 was added to the protein solution showed that pH shift during freezing and protein surface exposure were the main factors responsible for LDH instability at the lower freeze temperatures. Collectively, evidence is presented that supports the use of DoE-based systematic analysis at pilot scale in the identification of F/T process parameters critical for protein stability and in the development of suitable process control strategies.
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Affiliation(s)
- Ulrich Roessl
- Research Center Pharmaceutical Engineering GmbH, Graz, Austria.,Institute for Biotechnology and Biochemical Engineering, Graz University of Technology, Austria
| | - Sebastian Humi
- Research Center Pharmaceutical Engineering GmbH, Graz, Austria.,Institute for Biotechnology and Biochemical Engineering, Graz University of Technology, Austria
| | - Stefan Leitgeb
- Research Center Pharmaceutical Engineering GmbH, Graz, Austria.,Institute for Biotechnology and Biochemical Engineering, Graz University of Technology, Austria
| | - Bernd Nidetzky
- Institute for Biotechnology and Biochemical Engineering, Graz University of Technology, Austria.
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