1
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Lu M, Wu Y, Li Y, Ding L, Dai Z, Gu Q. Analysis of the adhesion mechanism of functionalized carbon nanotubes by molecular dynamics simulation. RSC Adv 2024; 14:21425-21431. [PMID: 38979464 PMCID: PMC11228758 DOI: 10.1039/d4ra02964j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2024] [Accepted: 06/30/2024] [Indexed: 07/10/2024] Open
Abstract
Although a lot of research has been carried out on the adhesion mechanism of gecko bristles, the research on materials inspired by gecko bristles is still limited to the design of geometric structure and the optimization of preparation process, and the adhesion mechanism of materials is still unclear. In this paper, the molecular structure of the end of the bristle-like material is focused on, and the interaction between functional group modified carbon nanotubes and the interface is analyzed by molecular dynamics simulation. Thus, the influence of different polar functional groups on the interfacial force between carbon nanotubes and silica is revealed, and the adhesion enhancement mechanism of polar groups on the interface between carbon nanotubes and silica is further verified.
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Affiliation(s)
- Mingyue Lu
- School of Mechanical Engineering, Jiangsu University of Technology Changzhou 213000 China
| | - Yanyan Wu
- School of Mechanical Engineering, Jiangsu University of Technology Changzhou 213000 China
| | - Yang Li
- Jiangsu Provincial Key Laboratory of Bionic Functional Materials, College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics Nanjing 210016 China
| | - Li Ding
- School of Mechanical Engineering, Jiangsu University of Technology Changzhou 213000 China
| | - Zhendong Dai
- Jiangsu Provincial Key Laboratory of Bionic Functional Materials, College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics Nanjing 210016 China
| | - Qinming Gu
- Key Laboratory for Precision and Non-Traditional Machining Technology of Ministry of Education, Dalian University of Technology Dalian 116024 China
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2
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Jadeja S, Kupcik R, Fabrik I, Sklenářová H, Lenčo J. A stationary phase with a positively charged surface allows for minimizing formic acid concentration in the mobile phase, enhancing electrospray ionization in LC-MS proteomic experiments. Analyst 2023; 148:5980-5990. [PMID: 37870390 DOI: 10.1039/d3an01508d] [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: 10/24/2023]
Abstract
The default choice of mobile phase acidifier for bottom-up LC-MS proteomic analyses is 0.10% formic acid because of its decent acidity, decent ion pairing ability, and low suppression of electrospray ionization. In recent years, state-of-the-art columns have been designed specifically to provide efficient separation even when using an MS-friendly mobile phase of low ionic strength. Despite this, no attempts have been made to improve the sensitivity of the MS-based analytical methods by reducing the amount of formic acid in the mobile phase. In this study, we evaluated the effect of reduced formic acid concentration in the mobile phase on the chromatographic behavior and MS response of peptides when separated using columns packed with a C18 stationary phase with a positively charged surface. Using 0.01% formic acid in the mobile phase maintained excellent chromatographic performance and increased MS signal response compared to the standard of 0.10%. The enhanced MS response translated to about 50% improved peptide identifications depending on the complexity and amount of sample injected. The increased retention of peptides at a reduced formic acid concentration was directly proportional to the number of acidic residues in the peptide sequence. The study was carried out by covering a spectrum of protein samples with varied complexity using analytical flow, micro-, and nanoflow regimes to expand the applicability in routine practice.
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Affiliation(s)
- Siddharth Jadeja
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 03 Hradec Králové, Czech Republic.
| | - Rudolf Kupcik
- Biomedical Research Centre, University Hospital Hradec Králové, Sokolská 581, 500 05 Hradec Králové, Czech Republic
| | - Ivo Fabrik
- Biomedical Research Centre, University Hospital Hradec Králové, Sokolská 581, 500 05 Hradec Králové, Czech Republic
| | - Hana Sklenářová
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 03 Hradec Králové, Czech Republic.
| | - Juraj Lenčo
- Department of Analytical Chemistry, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovského 1203/8, 500 03 Hradec Králové, Czech Republic.
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3
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Managing nonspecific adsorption to liquid chromatography hardware: A review. Anal Chim Acta 2023; 1250:340994. [PMID: 36898813 DOI: 10.1016/j.aca.2023.340994] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 02/19/2023]
Abstract
The choice of alternative materials over stainless steel hardware in the construction of liquid chromatography systems has unveiled the degree to which nonspecific adsorption impacts the reproducibility of LC methods. Some of the major contributors to nonspecific adsorption losses are charged metallic surfaces and leached metallic impurities, that may interact with the analyte and result in analyte loss and overall poor chromatographic performance. In this review, we describe several mitigation strategies available to chromatographers to minimize nonspecific adsorption to chromatographic systems. Alternative surfaces to stainless steel such as titanium, PEEK, and hybrid surface technologies are discussed. Furthermore, mobile phase additives used to prevent metal ion-analyte interactions are reviewed. Nonspecific adsorption of analytes is not reserved to metallic surfaces, as analytes may adsorb to the surfaces of filters, tubes, and pipette tips during sample preparation. Identifying the source of nonspecific interactions is paramount, as mitigation strategies may differ depending on what stage nonspecific losses are taking place. With this in mind, we discuss diagnostic methods that may help the chromatographer to differentiate losses resulting from sample preparation, and losses during LC runs.
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4
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Floros DJ, Xu K, Berthiller F, Schwartz-Zimmermann H. Comparison of chromatographic conditions for the targeted tandem mass spectrometric determination of 354 mammalian metabolites. J Chromatogr A 2023; 1697:463985. [PMID: 37062154 DOI: 10.1016/j.chroma.2023.463985] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/22/2023] [Accepted: 04/08/2023] [Indexed: 04/18/2023]
Abstract
Metabolomics is becoming increasingly popular in livestock research, but no single analytical method can cover the entire metabolome. As such, we compared similar and complementary chromatographic methods with respect to analyte coverage and chromatographic properties of mammalian metabolites. We investigated 354 biologically relevant primary metabolites from 19 compound classes including amino acids, bile acids, biogenic amines, carboxylic acids, lipids, nucleotides and sugars. A total of 2063 selected reaction monitoring transitions were optimized on a triple quadrupole mass spectrometer. We then determined the retention profiles and peak parameters of our compounds using an anion exchange chromatography (AIC), three reversed-phase (RP) and three hydrophilic interaction liquid chromatography (HILIC) methods. On average, HILIC methods covered 54% of all metabolites with retention factors >1, while average RP coverage was 41%. In contrast to RP, HILIC methods could also retain polar metabolites such as amino acids and biogenic amines. Carboxylic acids, nucleotides, and sugar related compounds were best separated by AIC or zwitterionic pHILIC with alkaline eluents. Combining two complementary HILIC and RP methods increased the library coverage to 92%. By further including important short chain fatty acids, a combination of HILIC, RP and AIC methods achieved a coverage of 97%. The resulting dataset of LC and MS/MS parameters will facilitate the development of tailor-made quantitative targeted LC-MS/MS methods to investigate the mammalian metabolome.
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Affiliation(s)
- Dimitrios J Floros
- Christian Doppler Laboratory for Innovative Gut Health Concepts of Livestock, Institute of Bioanalytics and Agro-Metabolomics, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Str. 20, 3430 Tulln, Austria
| | - Kangkang Xu
- Christian Doppler Laboratory for Innovative Gut Health Concepts of Livestock, Institute of Bioanalytics and Agro-Metabolomics, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Str. 20, 3430 Tulln, Austria
| | - Franz Berthiller
- Christian Doppler Laboratory for Innovative Gut Health Concepts of Livestock, Institute of Bioanalytics and Agro-Metabolomics, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Str. 20, 3430 Tulln, Austria.
| | - Heidi Schwartz-Zimmermann
- Christian Doppler Laboratory for Innovative Gut Health Concepts of Livestock, Institute of Bioanalytics and Agro-Metabolomics, Department of Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad-Lorenz-Str. 20, 3430 Tulln, Austria
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5
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Li X, Zhang J, Jin Y, Liu Y, Li N, Wang Y, Du C, Xue Z, Zhang N, Chen Q. Effect of pH-Dependent Homo/Heteronuclear CAHB on Adsorption and Desorption Behaviors of Ionizable Organic Compounds on Carbonaceous Materials. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:12118. [PMID: 36231423 PMCID: PMC9566536 DOI: 10.3390/ijerph191912118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/19/2022] [Accepted: 09/22/2022] [Indexed: 06/16/2023]
Abstract
Herein, the adsorption/desorption behaviors of benzoic acid (BA) and phthalic acid (PA) on three functionalized carbon nanotubes (CNTs) at various pH were investigated, and the charge-assisted H-bond (CAHB) was verified by DFT and FTIR analyses to play a key role. The results indicated that the adsorption order of BA and PA on CNTs was different from Kow of that at pH 2.0, 4.0, and 7.0 caused by the CAHB interaction. The strength of homonuclear CAHB (≥78.96 kJ·mol-1) formed by BA/PA on oxidized CNTs is stronger than that of heteronuclear CAHB formed between BA/PA and amino-functionalized CNTs (≤51.66 kJ·mol-1). Compared with the heteronuclear CAHB (Hysteresis index, HI ≥ 1.47), the stronger homonuclear CAHB leads to clearly desorption hysteresis (HI ≥ 3.51). Additionally, the contribution of homonuclear CAHB (≥52.70%) was also greater than that of heteronuclear CAHB (≤45.79%) at pH 7.0. These conclusions were further confirmed by FTIR and DFT calculation, and the crucial evidence of CAHB formation in FTIR was found. The highlight of this work is the identification of the importance and difference of pH-dependent homonuclear/heteronuclear CAHB on the adsorption and desorption behaviors of ionizable organic compounds on carbonaceous materials, which can provide a deeper understanding for the removal of ionizable organic compounds by designed carbonaceous materials.
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Affiliation(s)
- Xiaoyun Li
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi’an 710119, China
- International Joint Research Centre of Shaanxi Province for Pollutants Exposure and Eco-Environmental Health, Xi’an 710119, China
| | - Jinlong Zhang
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi’an 710119, China
| | - Yaofeng Jin
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi’an 710119, China
| | - Yifan Liu
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi’an 710119, China
| | - Nana Li
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi’an 710119, China
| | - Yue Wang
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi’an 710119, China
| | - Cong Du
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi’an 710119, China
| | - Zhijing Xue
- Department of Environmental Science, School of Geography and Tourism, Shaanxi Normal University, Xi’an 710119, China
| | - Nan Zhang
- Environmental Protection Department of Mahe Town, Yuyang District, Yulin 719000, China
| | - Qin Chen
- Northwest Land and Resource Research Center, Shaanxi Normal University, Xi’an 710119, China
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6
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Lardeux H, Goyon A, Zhang K, Nguyen JM, Lauber MA, Guillarme D, D'Atri V. The impact of low adsorption surfaces for the analysis of DNA and RNA oligonucleotides. J Chromatogr A 2022; 1677:463324. [PMID: 35858489 DOI: 10.1016/j.chroma.2022.463324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 12/20/2022]
Abstract
As interest in oligonucleotide (ON) therapeutics is increasing, there is a need to develop suitable analytical methods able to properly analyze those molecules. However, an issue exists in the adsorption of ONs on different parts of the instrumentation during their analysis. The goal of the present paper was to comprehensively evaluate various types of bioinert materials used in ion-pairing reversed-phase (IP-RPLC) and hydrophilic interaction chromatography (HILIC) to mitigate this issue for 15- to 100-mer DNA and RNA oligonucleotides. The whole sample flow path was considered under both conditions, including chromatographic columns, ultra-high-performance liquid chromatography (UHPLC) system, and ultraviolet (UV) flow cell. It was found that a negligible amount of non-specific adsorption might be attributable to the chromatographic instrumentation. However, the flow cell of a detector should be carefully subjected to sample-based conditioning, as the material used in the UV flow cell was found to significantly impact the peak shapes of the largest ONs (60- to 100-mer). Most importantly, we found that the choice of column hardware had the most significant impact on the extent of non-specific adsorption. Depending on the material used for the column walls and frits, adsorption can be more or less pronounced. It was proved that any type of bioinert RPLC/HILIC column hardware offered some clear benefits in terms of adsorption in comparison to their stainless-steel counterparts. Finally, the evaluation of a large set of ONs was performed, including a DNA duplex and DNA or RNA ONs having different base composition, furanose sugar, and modifications occurring at the phosphate linkage or at the sugar moiety. This work represents an important advance in understanding the overall ON adsorption, and it helps to define the best combination of materials when analyzing a wide range of unmodified and modified 20-mer DNA and RNA ONs.
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Affiliation(s)
- Honorine Lardeux
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), University of Geneva, CMU-Rue Michel Servet 1, Geneva 4 1211, Switzerland; School of Pharmaceutical Sciences, University of Geneva, CMU-Rue Michel Servet 1, Geneva 4 1211, Switzerland
| | - Alexandre Goyon
- Small Molecule Pharmaceutical Sciences, Genentech Inc., DNA Way, South San Francisco, CA 94080, USA
| | - Kelly Zhang
- Small Molecule Pharmaceutical Sciences, Genentech Inc., DNA Way, South San Francisco, CA 94080, USA
| | | | | | - Davy Guillarme
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), University of Geneva, CMU-Rue Michel Servet 1, Geneva 4 1211, Switzerland; School of Pharmaceutical Sciences, University of Geneva, CMU-Rue Michel Servet 1, Geneva 4 1211, Switzerland
| | - Valentina D'Atri
- Institute of Pharmaceutical Sciences of Western Switzerland (ISPSO), University of Geneva, CMU-Rue Michel Servet 1, Geneva 4 1211, Switzerland; School of Pharmaceutical Sciences, University of Geneva, CMU-Rue Michel Servet 1, Geneva 4 1211, Switzerland.
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7
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A universal approach to recover the original superhydrophilicity of micro/nano-textured metal or metal oxide surfaces. J Colloid Interface Sci 2022; 628:534-544. [PMID: 36007418 DOI: 10.1016/j.jcis.2022.08.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 07/20/2022] [Accepted: 08/07/2022] [Indexed: 11/20/2022]
Abstract
Micro/nano-textured metal or metal oxide surfaces that are naturally superhydrophilic will spontaneously transform into hydrophobic even superhydrophobic after being exposed to ambient air due to the adsorption of airborne organics. This fast wettability transition not only affects the true evaluation of surface wettability but also deteriorates the application performance. Albeit the mechanisms responsible for the wettability transition have been clarified, there is no universal method to recover the initial superhydrophilicity, and how the surface morphology affects the wettability transition is still unclear. Herein, we observe and compare the wettability transition of a wide variety of micro/nano-textured metal or metal oxide surfaces and propose a solvent cleaning method to recover their original superhydrophilicity. We prove that the spontaneously adsorbed organics can be removed by our proposed cleaning method while maintaining the original surface morphology and composition. Our proposed cleaning method is valid for both micro/nano-textured metal and metal oxide surfaces. We also prove that the rate of the wettability transition is not primarily affected by the specific area of surface structures but by the closeness of structural arrangement. Densely packed surface nanostructures can significantly delay the wettability transition by suppressing the diffusion of organic molecules. Our results help the true evaluation of surface wettability and provide a route for the design and preparation of long-lasting superhydrophilic surfaces.
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8
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McCalley DV. Influence of metals in the column or instrument on performance in hydrophilic interaction liquid chromatography. J Chromatogr A 2022; 1663:462751. [PMID: 34995861 DOI: 10.1016/j.chroma.2021.462751] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/13/2021] [Accepted: 12/13/2021] [Indexed: 10/19/2022]
Abstract
A method is proposed for measuring the relative contribution of extracolumn and column effects to the detrimental interactions which occur between metal-sensitive solutes and the complete HPLC system. The method involves the substitution of a length of narrow bore silica tubing for the column and measuring the extracolumn contribution, which is subtracted from the total bandspreading measured with a column in place to yield the column contribution. The investigation focussed on HILIC separations, which have been relatively little studied compared with similar effects in RPLC. Metal-solute interactions can lead to tailing peaks and reduced sensitivity or even irreversible adsorption of particularly challenging solutes such as mono-, di- and triphosphorylated nucleotides, which show strong interactions between their phosphate groups and metals. A deactivated HILIC column, treated by a vapour deposition procedure gave generally good results when using high pH (pH 9.0) mobile phases, which suppress the effects of metals. The addition of metal complexing agents such as citrate at low millimolar concentration gave further improvements in peak shape at high pH, and even micromolar concentrations of citrate or medronic acid showed good results. These lower concentrations are more favourable for LC-MS. Addition of the higher concentration of citrate gave acceptable results for the nucleotides even at low pH (pH 3.0). With the standard UHPLC instrument used, loss of efficiency due to metal solute interactions was 25% or less, with most losses due to interactions with the column, although this result will depend on the condition and design of the instrument, which is easily assessed by the proposed procedure.
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Affiliation(s)
- David V McCalley
- Centre for Research in Biosciences, University of the West of England, Frenchay, Coldharbour Lane, Bristol BS16 1QY, United Kingdom.
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9
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Guimaraes GJ, Bartlett MG. The critical role of mobile phase pH in the performance of oligonucleotide ion-pair liquid chromatography-mass spectrometry methods. Future Sci OA 2021; 7:FSO753. [PMID: 34840810 PMCID: PMC8610006 DOI: 10.2144/fsoa-2021-0084] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 09/29/2021] [Indexed: 11/24/2022] Open
Affiliation(s)
- Guilherme J Guimaraes
- Department of Pharmaceutical & Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA, USA
| | - Michael G Bartlett
- Department of Pharmaceutical & Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA, USA
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10
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Guimaraes GJ, Sutton JM, Gilar M, Donegan M, Bartlett MG. Impact of Nonspecific Adsorption to Metal Surfaces in Ion Pair-RP LC-MS Impurity Analysis of Oligonucleotides. J Pharm Biomed Anal 2021; 208:114439. [PMID: 34742118 DOI: 10.1016/j.jpba.2021.114439] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 12/11/2022]
Abstract
Nonspecific adsorption has been a consistent challenge in the analysis of oligonucleotides. Nonspecific adsorption is a result of interactions between charged acidic analytes and adsorption sites present in metallic surfaces located in the fluidic path of chromatography systems. Due to their high surface area, adsorption to column frits is especially concerning. Poor peak shape, low recovery and compromised LOQ have been associated with this phenomenon. Alternative methods including substitution of stainless steel for different hardware materials and mobile phase additives have been explored in an attempt to minimize this issue. Chemical modification of metal surfaces using hybrid surface technology (HST) by-passes the limitation of stainless steel construction material by forming a hybrid organic/inorganic layer that acts as a barrier and limits nonspecific interactions. In this study we explore the implications of this new technology in sensitive analysis and determination of relative impurity levels of oligonucleotides. Higher relative impurity levels and better reproducibility were obtained with columns using HST.
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Affiliation(s)
- Guilherme J Guimaraes
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, 250W. Green Street, Athens, Georgia 30602, United States
| | - J Michael Sutton
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, 250W. Green Street, Athens, Georgia 30602, United States
| | - Martin Gilar
- Waters Corporation, Milford, Massachusetts 01757, United States
| | - Michael Donegan
- Waters Corporation, Milford, Massachusetts 01757, United States
| | - Michael G Bartlett
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, 250W. Green Street, Athens, Georgia 30602, United States.
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11
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Kawaguchi H, Imanaka H, Imamura K, Ishida N. Direct measurements of interaction forces of bovine serum albumin and lysozyme with stainless steel by atomic force microscopy. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.127137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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12
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Gallegos A, Wu J. Molecular thermodynamics for amino‐acid adsorption at inorganic surfaces. AIChE J 2021. [DOI: 10.1002/aic.17432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alejandro Gallegos
- Department of Chemical and Environmental Engineering University of California Riverside California USA
| | - Jianzhong Wu
- Department of Chemical and Environmental Engineering University of California Riverside California USA
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13
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Birdsall RE, Kellett J, Ippoliti S, Ranbaduge N, Lauber MA, Yu YQ, Chen W. Reducing metal-ion mediated adsorption of acidic peptides in RPLC-based assays using hybrid silica chromatographic surfaces. J Chromatogr B Analyt Technol Biomed Life Sci 2021; 1179:122700. [PMID: 34329890 DOI: 10.1016/j.jchromb.2021.122700] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 03/05/2021] [Accepted: 04/02/2021] [Indexed: 10/21/2022]
Abstract
In this study we evaluate column hardware exhibiting a novel hybrid silica surface in its ability to mitigate metal-induced adsorption artifacts such as chromatographic peak tailing for acidic amino acid residue containing peptides. Using a conventional reversed-phase liquid chromatography (RPLC)-based method, chromatographic performance of a peptide map was compared using a traditional stainless-steel column and an equivalent column bearing a novel hybrid silica surface. Tailing factors for six peptides containing acidic amino acid residues (Tf ≥ 1.50) were observed to be reduced up to 80% to a nominal value Tf ≤ 1.2 with R.S.D. % ≤ 4%. Furthermore, recovery for two of the identified peptides exhibited increased recovery in addition to reduced peak tailing when using the column bearing the hybrid silica surface. Performance was unaffected for peaks where there were no implications of metal induced effects. Collectively, this study demonstrates that the novel hybrid silica surface can effectively reduce peak tailing for acidic residue containing peptides.
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Affiliation(s)
- Robert E Birdsall
- Waters Corporation, 34 Maple Street, Milford, MA 01757, United States.
| | - Jacob Kellett
- Waters Corporation, 34 Maple Street, Milford, MA 01757, United States.
| | - Samantha Ippoliti
- Waters Corporation, 34 Maple Street, Milford, MA 01757, United States.
| | - Nilini Ranbaduge
- Waters Corporation, 34 Maple Street, Milford, MA 01757, United States.
| | - Matthew A Lauber
- Waters Corporation, 34 Maple Street, Milford, MA 01757, United States.
| | - Ying Qing Yu
- Waters Corporation, 34 Maple Street, Milford, MA 01757, United States.
| | - Weibin Chen
- Waters Corporation, 34 Maple Street, Milford, MA 01757, United States.
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14
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Gilar M, DeLano M, Gritti F. Mitigation of analyte loss on metal surfaces in liquid chromatography. J Chromatogr A 2021; 1650:462247. [PMID: 34087520 DOI: 10.1016/j.chroma.2021.462247] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 04/21/2021] [Accepted: 05/07/2021] [Indexed: 10/21/2022]
Abstract
The adsorptive loss of acidic analytes in liquid chromatography was investigated using metal frits. Repetitive injections of acidic small molecules or an oligonucleotide were made on individual 2.1 or 4.6 mm i.d. column frits. Losses were observed for adenosine 5'-(α,β-methylene) diphosphate, 2-pyridinol 1-oxide and the 25-mer phosphorothioate oligonucleotide Trecovirsen (GEM91) on stainless steel and titanium frits. Analyte adsorption was greatest at acidic pH due to the positive charge on the metal oxide surface. Analyte recovery increased when a series of injections was performed; this effect is known as sample conditioning. Nearly complete recovery was achieved when the metal adsorptive sites were saturated with the analyte. A similar effect was achieved by conditioning the frits with phosphoric, citric or etidronic acids, or their buffered solutions. These procedures can be utilized to mitigate analyte loss. However, the effect is temporary, as the conditioning agent is gradually removed by the running mobile phase. Metal frits modified with hybrid organic/inorganic surface technology were shown to mitigate analyte-to-metal surface interactions and improve recovery of acidic analytes. Quantitative recovery of a 15-35 mer oligodeoxythymidine mixture was achieved using column hardware modified with hybrid surface technology, without a need for column conditioning prior to analysis.
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Affiliation(s)
- Martin Gilar
- Waters Corporation, 34 Maple Street, Milford, MA 01757, USA.
| | - Mathew DeLano
- Waters Corporation, 34 Maple Street, Milford, MA 01757, USA
| | - Fabrice Gritti
- Waters Corporation, 34 Maple Street, Milford, MA 01757, USA
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15
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DeLano M, Walter TH, Lauber MA, Gilar M, Jung MC, Nguyen JM, Boissel C, Patel AV, Bates-Harrison A, Wyndham KD. Using Hybrid Organic-Inorganic Surface Technology to Mitigate Analyte Interactions with Metal Surfaces in UHPLC. Anal Chem 2021; 93:5773-5781. [PMID: 33798331 DOI: 10.1021/acs.analchem.0c05203] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Interactions of analytes with metal surfaces in high-performance liquid chromatography (HPLC) instruments and columns have been reported to cause deleterious effects ranging from peak tailing to a complete loss of the analyte signal. These effects are due to the adsorption of certain analytes on the metal oxide layer on the surface of the metal components. We have developed a novel surface modification technology and applied it to the metal components in ultra-HPLC (UHPLC) instruments and columns to mitigate these interactions. A hybrid organic-inorganic surface, based on an ethylene-bridged siloxane chemistry, was developed for use with reversed-phase and hydrophilic interaction chromatography. We have characterized the performance of UHPLC instruments and columns that incorporate this surface technology and compared the results with those obtained using their conventional counterparts. We demonstrate improved performance when using the hybrid surface technology for separations of nucleotides, a phosphopeptide, and an oligonucleotide. The hybrid surface technology was found to result in higher and more consistent analyte peak areas and improved peak shape, particularly when using low analyte mass loads and acidic mobile phases. Reduced abundances of iron adducts in the mass spectrum of a peptide were also observed when using UHPLC systems and columns that incorporate hybrid surface technology. These results suggest that this technology will be particularly beneficial in UHPLC/mass spectrometry investigations of metal-sensitive analytes.
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Affiliation(s)
- Mathew DeLano
- Waters Corporation, 34 Maple Street, Milford, Massachusetts 01757, United States
| | - Thomas H Walter
- Waters Corporation, 34 Maple Street, Milford, Massachusetts 01757, United States
| | - Matthew A Lauber
- Waters Corporation, 34 Maple Street, Milford, Massachusetts 01757, United States
| | - Martin Gilar
- Waters Corporation, 34 Maple Street, Milford, Massachusetts 01757, United States
| | - Moon Chul Jung
- Waters Corporation, 34 Maple Street, Milford, Massachusetts 01757, United States
| | - Jennifer M Nguyen
- Waters Corporation, 34 Maple Street, Milford, Massachusetts 01757, United States
| | - Cheryl Boissel
- Waters Corporation, 34 Maple Street, Milford, Massachusetts 01757, United States
| | - Amit V Patel
- Waters Corporation, 34 Maple Street, Milford, Massachusetts 01757, United States
| | | | - Kevin D Wyndham
- Waters Corporation, 34 Maple Street, Milford, Massachusetts 01757, United States
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Soares SF, Rocha MJ, Ferro M, Amorim CO, Amaral JS, Trindade T, Daniel-da-Silva AL. Magnetic nanosorbents with siliceous hybrid shells of alginic acid and carrageenan for removal of ciprofloxacin. Int J Biol Macromol 2019; 139:827-841. [PMID: 31394147 DOI: 10.1016/j.ijbiomac.2019.08.030] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 07/30/2019] [Accepted: 08/05/2019] [Indexed: 12/12/2022]
Abstract
Water contamination with antibiotics is a serious environmental threat. Ciprofloxacin (CIP) is one of the most frequently detected antibiotics in water. Herein, silica-based magnetic nanosorbents prepared using three seaweed polysaccharides, alginic acid, κ- and λ-carrageenan, were developed and evaluated in the uptake of ciprofloxacin. The sorbents were firstly characterized in detail to assess their morphology and composition. A systematic investigation was conducted to study the adsorption performance towards CIP, by varying the initial pH, contact time and initial CIP concentration. The maximum adsorption capacity was 464, 423 and 1350 mg/g for particles prepared from alginic acid, κ- and λ-carrageenan respectively. These high values indicate that these materials are among the most effective sorbents reported so far for the removal of CIP from water. The kinetic data were consistent with the pseudo-second-order model. The CIP adsorption on λ-carrageenan particles followed a cooperative process with sigmoidal isotherm that was described by the Dubinin-Radushkevich model. The high charge density of λ-carrageenan and the propensity of CIP molecules to self-aggregate may explain the cooperative nature of CIP adsorption. The sorbents were easily regenerated in mild conditions and could be reused in CIP removal up to 4 times without a significant loss of adsorptive properties.
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Affiliation(s)
- Sofia F Soares
- CICECO-Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Maria João Rocha
- CICECO-Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Marta Ferro
- CICECO - Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Carlos O Amorim
- CICECO-Aveiro Institute of Materials, Department of Physics, University of Aveiro, Aveiro, 3810-193, Portugal
| | - João S Amaral
- CICECO-Aveiro Institute of Materials, Department of Physics, University of Aveiro, Aveiro, 3810-193, Portugal
| | - Tito Trindade
- CICECO-Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Ana L Daniel-da-Silva
- CICECO-Aveiro Institute of Materials, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
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17
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Zhang X, Chen L, Yuan L, Liu R, Li D, Liu X, Ge G. Conformation-Dependent Coordination of Carboxylic Acids with Fe 3O 4 Nanoparticles Studied by ATR-FTIR Spectral Deconvolution. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5770-5778. [PMID: 30458104 DOI: 10.1021/acs.langmuir.8b03303] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The coordination of valeric acid (VA), glutaric acid (GA), and tricarballylic acid (TA) with Fe-OH on the Fe3O4 nanoparticle surface has been systematically studied to elucidate the effects of COOH, molecular configuration, and ligand concentration on the coordination by the combined use of attenuated total reflectance Fourier transform infrared (ATR-FTIR) and thermogravimetric analysis (TGA). The results show that the binding ability of the acids increases with the increase in the COOH number. Multiple conformations coexist for the dicarboxylic and tricarboxylic acid coordinated on the iron oxide NPs. Saturated coordination formed with only a one-, two-, or three-COOH conformation for VA, GA, and TA, respectively, occurs under ligand-scarce conditions, while unsaturated coordination formed with the mixture of uncoordinated, one-, and/or two-COOH conformations for VA, GA, and TA, respectively, exists under ligand-abundant conditions. The maximum coordination numbers for monolayer adsorption for VA, GA, and TA on Fe3O4 NPs are 9, 2.4, and 2.7 nm-2, respectively. This study helps us to understand the fine coordination mechanism caused by the acid molecules with different configurations and elucidates, for the first time, the fine conformational variance incurred by the surrounding ligand with different concentrations and the way in which the ligand is added.
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Affiliation(s)
- Xiaorui Zhang
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology , Beijing 100190 , P. R. China
- University of Chinese Academy of Sciences , No. 19(A) Yuquan Road , Beijing 100049 , P. R. China
| | - Lan Chen
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology , Beijing 100190 , P. R. China
| | - Li Yuan
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology , Beijing 100190 , P. R. China
| | - Renxiao Liu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology , Beijing 100190 , P. R. China
| | - Dexing Li
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology , Beijing 100190 , P. R. China
| | - Xiaoping Liu
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology , Beijing 100190 , P. R. China
| | - Guanglu Ge
- CAS Key Laboratory of Standardization and Measurement for Nanotechnology, CAS Center for Excellence in Nanoscience , National Center for Nanoscience and Technology , Beijing 100190 , P. R. China
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18
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Loupe N, Doan J, Smotkin ES. Twenty years of operando IR, X-ray absorption, and Raman spectroscopy: Direct methanol and hydrogen fuel cells. Catal Today 2017. [DOI: 10.1016/j.cattod.2016.06.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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19
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Shi J, Li F, Yin D, Xu Z, Cheng L. Sorption and degradation of phthalate esters by a novel functional hyper-cross-linked polymer. CHEMOSPHERE 2017; 171:149-157. [PMID: 28013076 DOI: 10.1016/j.chemosphere.2016.12.048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 12/04/2016] [Accepted: 12/10/2016] [Indexed: 06/06/2023]
Abstract
A novel functional hyper-cross-linked polymer (NFHP) modified with trimethylamine was prepared. NFHP was characterized by FTIR, XPS, XRD, SEM and Micromeritics ASAP-2010 automatic surface area analysis instrument. Adsorption and hydrolysis degradation of phthalate acid esters (PAEs) by NFHP were also investigated as a function of temperature, equilibrium concentration and PAEs types. Results indicated that NFHP could adsorb and catalyze hydrolysis of PAEs simultaneously. There was a positive relationship between the removal capacity and temperature, equilibrium concentration, and PAEs hydrophobicity. However, the increase of PAEs equilibrium concentration and hydrophobicity resulted in the decreased level of their hydrolysis, while high temperature promoted the hydrolysis of PAEs. Film diffusion was the rate controlling step of the removal process. The apparent removal rate of PAEs increased as temperature increased due to the higher diffusion coefficient at higher temperature. The results of continuous fixed-bed runs demonstrated that NFHP was capable of synchronously removing PAEs and their hydrolysis products from tap water. In the effluent solution, the PAEs concentration was below the detection limit (0.01 mg/L) of HPLC within 1400 BVs. Moreover, the exhausted NFHP beads can be completely regenerated for repeated use. Physical adsorption, hydrolysis degradation and ion-exchange played significant roles in removing of PAEs and their hydrolysis products. The analysis of hydrolysis products, FTIR and XPS spectra proved that physical adsorption, hydrolysis and ion-exchange were the main removal mechanism. The results reported herein suggested that this novel material has a great potential in efficient removal of PAEs from wastewater.
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Affiliation(s)
- Jing Shi
- School of Engineering, China Pharmaceutical University, Nanjing 211198, People's Republic of China
| | - Fei Li
- School of Environmental Science & Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, People's Republic of China
| | - Danyang Yin
- School of Environmental Science & Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, People's Republic of China
| | - Zhengwen Xu
- School of Environmental Science & Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, People's Republic of China; Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Nanjing University of Information Science & Technology, Nanjing 210044, People's Republic of China.
| | - Ling Cheng
- School of Environmental Science & Engineering, Nanjing University of Information Science and Technology, Nanjing 210044, People's Republic of China
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20
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Imamura K, Oshita M, Iwai M, Kuroda T, Watanabe I, Sakiyama T, Nakanishi K. Influences of properties of protein and adsorption surface on removal kinetics of protein adsorbed on metal surface by H2O2-electrolysis treatment. J Colloid Interface Sci 2010; 345:474-80. [PMID: 20199779 DOI: 10.1016/j.jcis.2010.01.083] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Revised: 01/24/2010] [Accepted: 01/27/2010] [Indexed: 10/19/2022]
Abstract
"H(2)O(2)-electrolysis" treatment is an alternative method for removing proteinaceous materials that are adsorbed to metal surfaces. The method is based on the generation of hydroxyl radicals by electrolysis of hydrogen peroxide and the subsequent decomposition of organic substances adhering to the metal surface. We herein investigated the influence of some parameters on the kinetics of protein removal by H(2)O(2)-electrolysis. These parameters included the properties of proteins and the type of metal surface. Sixteen types of proteins and nine types of metal surfaces were used. The removal of adsorbed protein from a metal surface during the treatment was monitored by ellipsometry. Apparent first-order rate constants for removal, k(c)(l), for various adsorption and treatment conditions were determined. The k(c)(l) value varied markedly with the type of protein and was also influenced by the pH used in the adsorption. The isoelectric point (pI) of protein used was found to be a major factor. The amount of adsorbed protein removed by a unit amount of (·)OH was larger for a metal surface with a lower pI. The impact of the properties of the protein and metal surface on the removal kinetics are discussed, focusing on relationships with the adsorption characteristics of the protein.
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Affiliation(s)
- Koreyoshi Imamura
- Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, Okayama 700-8530, Japan.
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21
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Imamura K, Shimomura M, Nagai S, Akamatsu M, Nakanishi K. Adsorption characteristics of various proteins to a titanium surface. J Biosci Bioeng 2009; 106:273-8. [PMID: 18930005 DOI: 10.1263/jbb.106.273] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2008] [Accepted: 06/17/2008] [Indexed: 11/17/2022]
Abstract
Adsorption characteristics of 18 proteins, with different sizes and isoelectric points, to a titanium oxide surface were studied. The adsorption isotherms were categorized based on protein type and pH: type 1, irreversible adsorption; type 2, Langmuir-type reversible adsorption; and type 3, reversible and irreversible adsorption. Most of the proteins tested were irreversibly adsorbed in the pH range of 3-8, whereas most adsorbed reversibly at pH 8.5-9.4. Protamine, with a pI value of 12, adsorbed reversibly in the pH range of 3-9. pH values that gave maximal sums of irreversibly and reversibly adsorbed proteins were in the pH range of 3-8 and tended to increase slightly with the pI value of the corresponding protein. pH values that gave maximal quantities of irreversibly adsorbed protein ranged between 4-6 and were nearly independent of pI.
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Affiliation(s)
- Koreyoshi Imamura
- Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, Tsushima-Naka, Okayama 700-8530, Japan
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22
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Imamura K, Kawasaki Y, Nagayasu T, Sakiyama T, Nakanishi K. Adsorption characteristics of oligopeptides composed of acidic and basic amino acids on titanium surface. J Biosci Bioeng 2007; 103:7-12. [PMID: 17298894 DOI: 10.1263/jbb.103.7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Accepted: 09/28/2006] [Indexed: 11/17/2022]
Abstract
The adsorption characteristics of octapeptides, containing different numbers of aspartic acid, lysine, and alanine residues (i.e., D(4)K(0)A(4), D(4)K(1)A(3), D(4)K(3)A(1), D(4)K(4)A(0), and D(0)K(4)A(4)) on the surface of titanium (Ti) particles were investigated in the pH range of 3.0-8.8 at 30 degrees C. The adsorption isotherms for octapeptides having four plural aspartic acid residues with or without lysine residues showed two distinct adsorption modes, i.e., irreversible and reversible modes, at pHs 3.0-6.5; at pH 7.0 or higher, the adsorption mode was reversible. Increasing the number of lysine residues at a fixed number of aspartic acid residues (i.e., 4) decreased the amount of peptides adsorbed in both modes. D(4)K(4)A(0) adsorbed irreversibly at pHs 3.0-6.5, due to the fact that negatively charged carboxyl groups directly interact with a positively charged Ti surface, whereas positively charged amino groups of lysine residues are directed in an opposite direction toward the solution side, as predicted by molecular mechanics/dynamics calculations.
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Affiliation(s)
- Koreyoshi Imamura
- Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, Tsushima-naka, Okayama 700-8530, Japan
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Nagayasu T, Imamura K, Nakanishi K. Adsorption characteristics of various organic substances on the surfaces of tantalum, titanium, and zirconium. J Colloid Interface Sci 2005; 286:462-70. [PMID: 15897059 DOI: 10.1016/j.jcis.2005.01.023] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2004] [Accepted: 01/18/2005] [Indexed: 11/15/2022]
Abstract
Adsorption characteristics of carboxylic acids, amines, an octapeptide composed of four L-alanine and four L-aspartic acid residues (Peptide-A4D4), and beta-lactoglobulin (beta-Lg) on tantalum (Ta), titanium (Ti), and zirconium (Zr) particles were examined at 30 degrees C and in some case, were compared with their adsorption onto SUS316L stainless steel particles (S6L). The adsorption isotherms on the Ta, Ti, and Zr particles could usually be expressed either by a Langmuir-type equation for reversible adsorption or by a modified Langmuir-type adsorption equation including terms for both reversible and irreversible adsorption. The adsorption equilibrium of benzoic acid, benzylamine, and m-xylylenediamine on all the metal surfaces followed a Langmuir-type equation, while those of phthalic acid, mellitic acid, and Peptide-A4D4 could be fitted to the modified Langmuir-type adsorption equation. The adsorption characteristics of different adsorbates on the different surfaces were discussed particularly with reference to the pH dependencies of the q(irrev), q(rev), and K values and the electrostatic properties of the oxidized surface of the metal particles. Fourier transform infrared spectroscopic analyses using a reflection/absorption technique (RA-IR) indicated that phthalic acid and mellitic acid are adsorbed in similar adsorption states irrespective of the type of metal. beta-Lg was adsorbed onto the surfaces principally in an irreversible manner. The desorption behavior of beta-Lg from Ta, Ti, and S6L surfaces was examined, in order to evaluate the extent of interaction between beta-Lg and the metals.
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Affiliation(s)
- Takeshi Nagayasu
- Department of Bioscience and Biotechnology, Faculty of Engineering, Okayama University, 3-1-1 Tsushima-naka, Okayama 700-8530, Japan
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