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Journal ArticleDOI

Microdroplet Ultrafast Reactions Speed Antibody Characterization.

02 Mar 2021-Analytical Chemistry (American Chemical Society (ACS))-Vol. 93, Iss: 8, pp 3997-4005
TL;DR: It is found that the IgG1 antibody can be digested completely by the IdeS protease in aqueous microdroplets in 250 microseconds, a 7.5 million-fold improvement in speed in comparison to traditional digestion in bulk solution (>30 min).
Abstract: Recently, microdroplet reactions have aroused much interest because the microdroplet provides a unique medium where organic reactions could be accelerated by a factor of 103 or more. However, microdroplet reactions of proteins have been rarely studied. We report the occurrence of multiple-step reactions of a large protein, specifically, the digestion, reduction, and deglycosylation of an intact antibody, which can take place in microseconds with high reaction yields in aqueous microdroplets at room temperature. As a result, fast structural characterization of a monoclonal antibody, essential for assessing its quality as a therapeutic drug, can be enabled. We found that the IgG1 antibody can be digested completely by the IdeS protease in aqueous microdroplets in 250 microseconds, a 7.5 million-fold improvement in speed in comparison to traditional digestion in bulk solution (>30 min). Strikingly, inclusion of the reductant tris(2-carboxyethyl)phosphine in the spray solution caused simultaneous antibody digestion and disulfide bond reduction. Digested and reduced antibody fragments were either collected or analyzed online by mass spectrometry. Further addition of PNGase F glycosylase into the spray solution led to antibody deglycosylation, thereby producing reduced and deglycosylated fragments of analytical importance. In addition, glycated fragments of IgG1 derived from glucose modification were identified rapidly with this ultrafast digestion/reduction technique. We suggest that microdroplets can serve as powerful microreactors for both exploring large-molecule reactions and speeding their structural analyses.
Citations
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Posted Content
TL;DR: In this article, the authors investigated the solvation of methane and methane decorated with charges in spherically confined water droplets and showed that the droplet surfaces are strongly favorable as compared to the interior.
Abstract: We investigate the solvation of methane and methane decorated with charges in spherically confined water droplets. Free energy profiles for a single methane molecule in droplets, ranging in diameter D, from 1 to 4 nm, show that the droplet surfaces are strongly favorable as compared to the interior. From the temperature dependence of the free energy in D=3 nm, we show that this effect is entropically driven. The potentials of mean force (PMFs) between two methane molecules show that the solvent separated minimum in the bulk is completely absent in confined water, independent of the droplet size since the solute particles are primarily associated with the droplet surface. The tendency of methanes with charges (Mq+ and Mq- with q+ = q- = 0.4e, where e is the electronic charge) to be pinned at the surface depends dramatically on the size of the water droplet. When D=4 nm, the ions prefer the interior whereas for D<4 nm the ions are localized at the surface, but with much less tendency than for methanes. Increasing the ion charge to e makes the surface strongly unfavorable. Reflecting the charge asymmetry of the water molecule, negative ions have a stronger preference for the surface compared to positive ions of the same charge magnitude. With increasing droplet size, the PMFs between Mq+ and Mq- show decreasing influence of the boundary due to the reduced tendency for surface solvation. We also show that as the solute charge density decreases the surface becomes less unfavorable. The implications of our results for the folding of proteins in confined spaces are outlined.

48 citations

Journal ArticleDOI
TL;DR: The kinetics of organic reactions of different types in microvolumes (droplets, thin films, and sealed tubes) show effects of gas/solution interfacial area, reaction molecularity and solvent polarity as discussed by the authors.
Abstract: The kinetics of organic reactions of different types in microvolumes (droplets, thin films, and sealed tubes) show effects of gas/solution interfacial area, reaction molecularity and solvent polarity. Partial solvation at the gas/solution interface is a major contributor to the 104 -fold reaction acceleration seen in bimolecular but not unimolecular reactions in microdroplets. Reaction acceleration can be used to manipulate selectivity by solvent choice.

30 citations

Journal ArticleDOI
Xin Yan1
TL;DR: In this paper, a minireview describes the unique reactivities in microdroplets and acceleration mechanisms with examples of experimental and theoretical studies, as well as various methods for scale-up of microdroplet reactions and the accelerated derivatization for in-situ molecular analysis.

21 citations

Journal ArticleDOI
TL;DR: In this paper , the formation of a molecular adduct with the water radical cation is observed in the positive ion mass spectrum while its formation in the interfacial region of the microdroplet (i.e., at the air-droplet interface) is indicated by the strong dependence of the oxidation product formation on the spray distance and the solvent composition.
Abstract: Spontaneous oxidation of compounds containing diverse X=Y moieties (e.g., sulfonamides, ketones, esters, sulfones) occurs readily in organic-solvent microdroplets. This surprising phenomenon is proposed to be driven by the generation of an intermediate species [M+H2O]+·: a covalent adduct of water radical cation (H2O +· ) with the reactant molecule (M). The adduct is observed in the positive ion mass spectrum while its formation in the interfacial region of the microdroplet (i.e., at the air-droplet interface) is indicated by the strong dependence of the oxidation product formation on the spray distance (which reflects the droplet size and consequently the surface-to-volume ratio) and the solvent composition. Importantly, based on the screening of a ca. 21,000-compound library and the detailed consideration of six functional groups, the formation of a molecular adduct with the water radical cation is a significant route to ionization in positive ion mode electrospray, where it is favored in those compounds with X=Y moieties which lack basic groups. A set of model monofunctional systems was studied and in one case, benzyl benzoate, evidence was found for oxidation driven by hydroxyl radical adduct formation followed by protonation in addition to the dominant water radical cation addition process. Significant implications of molecular ionization by water radical cations for oxidation processes in atmospheric aerosols, analytical mass spectrometry and small-scale synthesis are noted.

19 citations

Journal ArticleDOI
TL;DR: In this paper, a point-of-care (POC) test paper was developed for the analysis of EB aldehydes, which are potential biomarkers for lung cancer.
Abstract: Volatile organic compounds (VOCs) from exhaled breath (EB) are considered to be promising biomarkers for lung diseases. A convenient and sensitive point-of-care (POC) testing method for EB VOCs is essential. Here, we developed a POC test paper for the analysis of EB aldehydes, which are potential biomarkers for lung cancer. A probe molecule, 4-aminothiophenol (4-ATP), was anchored on a paper substrate to specifically capture gas-phase aldehydes through the Schiff base reaction. Meanwhile, thin-film reaction acceleration was utilized to increase capture efficiency. By directly coupling the test paper to a mass spectrometer through paper spray, high sensitivity (0.1 ppt) and a wide quantification linear range (from 10 ppt to 1 ppm) were obtained. Analysis of EB from lung cancer patients with the test paper showed a significant increase in several reported aldehyde markers compared to EB from healthy volunteers, indicating the potential of this method for sensitive, low-cost, and convenient lung cancer screening and diagnosis.

15 citations

References
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Journal ArticleDOI
TL;DR: Current knowledge of methods and avenues for their exploitation in the clinic are summarized, which allow the production of rMAbs bearing pre-selected oligosaccharides — glycoforms — to provide maximum efficacy for a given disease indication.
Abstract: To date, more than 20 recombinant immunoglobulin G (IgG) antibody therapeutics are licensed for the treatment of various diseases The mechanism of action of recombinant monoclonal antibodies (rMAbs) has been extensively investigated and several distinct pathways have been defined; selective activation of specific pathways may optimize clinical outcomes for different diseases, such as cancer and chronic inflammation Human IgG is a glycoprotein with oligosaccharides attached at a single site These are essential to the mode of action of rMAbs, and the antibody efficacy can vary depending on the particular oligosaccharide that is attached Methods are now becoming available that allow the production of rMAbs bearing pre-selected oligosaccharides - glycoforms - to provide maximum efficacy for a given disease indication This Review summarizes current knowledge of these methods and avenues for their exploitation in the clinic

781 citations

Journal ArticleDOI
Paul Carter1, Greg A. Lazar1
TL;DR: This Review focuses on emerging and novel mechanisms of action of antibodies and innovative targeting strategies that could extend their therapeutic applications, including antibody–drug conjugates, bispecific antibodies and antibody engineering to facilitate more effective delivery.
Abstract: Antibody therapeutics are now established as a major drug class. Here, Carter and Lazar comprehensively discuss current and emerging platforms and technologies for antibody therapeutics, with an emphasis on approaches that could extend their therapeutic applications, including antibody–drug conjugates, bispecific antibodies and antibody engineering to enable more effective delivery.

528 citations

Journal ArticleDOI
TL;DR: On-line droplet-droplet extraction occurs when a sample spray intersects a reagent electrospray; this allows continuous analysis of trace amounts of compounds directly in complex matrices including undiluted urine, milk and polluted water over extended periods of time.

437 citations

Journal ArticleDOI
TL;DR: The reasoning behind the Critical Path Initiative is explained and examples of successful consortia are discussed, which show the use of public-private partnerships and Consortia to accomplish the needed research.
Abstract: Societal expectations about drug safety and efficacy are rising while productivity in the pharmaceutical industry is falling. In 2004, the US Food and Drug Administration introduced the Critical Path Initiative with the intent of modernizing drug development by incorporating recent scientific advances, such as genomics and advanced imaging technologies, into the process. An important part of the initiative is the use of public-private partnerships and consortia to accomplish the needed research. This article explicates the reasoning behind the Critical Path Initiative and discusses examples of successful consortia.

393 citations