Publications by authors named "Yuetian Chen"

20 Publications

  • Page 1 of 1

Zwitterion-Functionalized SnO Substrate Induced Sequential Deposition of Black-Phase FAPbI with Rearranged PbI Residue.

Adv Mater 2022 Aug 11;34(32):e2203143. Epub 2022 Jul 11.

School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, China.

Black-phase formamidinium lead iodide (FAPbI ) with narrow bandgap and high thermal stability has emerged as the most promising candidate for highly efficient and stable perovskite photovoltaics. In order to overcome the intrinsic difficulty of black-phase crystallization and to eliminate the lead iodide (PbI ) residue, most sequential deposition methods of FAPbI -based perovskite will introduce external ions like methylammonium (MA ), cesium (Cs ), and bromide (Br ) ions to the perovskite structure. Here a zwitterion-functionalized tin(IV) oxide (SnO ) is introduced as the electron-transport layer (ETL) to induce the crystallization of high-quality black-phase FAPbI . The SnO ETL treated with the zwitterion of formamidine sulfinic acid (FSA) can help rearrange the stack direction, orientation, and distribution of residual PbI in the perovskite layer, which reduces the side effect of the residual PbI . Besides, the FSA functionalization also modifies SnO ETL to suppress deep-level defects at the perovskite/SnO interface. As a result, the FSA-FAPbI -based perovskite solar cells (PSCs) exhibit an excellent power conversion efficiency of up to 24.1% with 1000 h long-term operational stability. These findings provide a new interface engineering strategy on the sequential fabrication of black-phase FAPbI PSCs with improved optoelectronic performance.
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http://dx.doi.org/10.1002/adma.202203143DOI Listing
August 2022

Stable Pure Iodide MACsPbI Perovskite toward Efficient 1.6 eV Bandgap Photovoltaics.

J Phys Chem Lett 2022 Jun 2:5088-5093. Epub 2022 Jun 2.

School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai 200240, China.

Perovskite photovoltaics with the advantages of facile fabrication and high efficiency have been the rising star in the field for a decade. Methylammonium lead triiodide (MAPbI) was the first widely studied perovskite to initiate the boom of perovskite photovoltaics, but it was later considered thermodynamically instable for commercialization. Here, we demonstrate that simple cesium (Cs) doping without any complicated process can form a stable MA-based perovskite with a widened bandgap, which may broaden the application of MA-based perovskites in tandem solar cells. A record-high efficiency of ≤22% is thus achieved for a 1.6 eV bandgap perovskite solar cell. This work not only provides a new stable and efficient pure iodide candidate as a 1.6 eV bandgap perovskite but also reveals that Cs incorporation can help improve the efficiency and stability of MA-based perovskites.
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http://dx.doi.org/10.1021/acs.jpclett.2c01356DOI Listing
June 2022

Electro-Reforming Polyethylene Terephthalate Plastic to Co-Produce Valued Chemicals and Green Hydrogen.

J Phys Chem Lett 2022 Jan 12;13(2):622-627. Epub 2022 Jan 12.

School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.

Upcycling plastic waste pollution for sustainable resources and energy is an ideal solution to plastic waste-related environmental issues. Polyethylene terephthalate (PET), one of the most prominent single-use daily plastics with up to millions of tons produced annually, has recently been explored with respect to chemical recycling to ameliorate its environmental impact. In this work, we report an electrochemical upcycling approach to electrocatalytic oxidation of PET hydrolysate using Cu-based nanowire catalysts. We demonstrate that the electrocatalyst can catalyze the ethylene glycol (EG) molecule derived from PET waste toward formate with high selectivity and exhibit a lower onset potential for EG oxidation than for water oxidation. Experimental and density functional theory calculation results reveal that the oxidation pathway of EG on CuO can selectively break the C-C bond to generate formic acid. This work sheds light on employing earth-abundant metal catalysts to convert PET plastic waste to produce valued chemicals and green hydrogen.
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http://dx.doi.org/10.1021/acs.jpclett.1c03658DOI Listing
January 2022

Potential lead toxicity and leakage issues on lead halide perovskite photovoltaics.

J Hazard Mater 2022 03 20;426:127848. Epub 2021 Nov 20.

School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China. Electronic address:

Recently, lead halide perovskite solar cells have become a promising next-generation photovoltaics candidate for large-scale application to realize low-cost renewable electricity generation. Although perovskite solar cells have tremendous advantages such as high photovoltaic performance, low cost and facile solution-based fabrication, the issues involving lead could be one of the main obstacles for its commercialization and large-scale applications. Lead has been widely used in photovoltaics industry, yielding its environmental and health issues of vital importance because of the widespread application of photovoltaics. When the solar cell panels especially perovskite solar cells are damaged, lead would possibly leak into the surrounding environment, causing air, soil and groundwater contamination. Therefore, lots of research efforts have been put into evaluating the lead toxicity and potential leakage issues, as well as studying the encapsulation of lead to deal with leakage issue during fire hazard and precipitation in photovoltaics. In this review, we summarize the latest progress on investigating the lead safety issue on photovoltaics, especially lead halide perovskite solar cells, and the corresponding solutions. We also outlook the future development towards solving the lead safety issues from different aspects.
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http://dx.doi.org/10.1016/j.jhazmat.2021.127848DOI Listing
March 2022

Deep-Red Perovskite Light-Emitting Diodes Based on One-Step-Formed γ-CsPbI Cuboid Crystallites.

Adv Mater 2021 Dec 10;33(51):e2105699. Epub 2021 Oct 10.

School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, China.

Inorganic CsPbI perovskite with high chemical stability is attractive for efficient deep-red perovskite light-emitting diodes (PeLEDs) with high color purity. Compared to PeLEDs based on ex-situ-synthesized CsPbI nanocrystals/quantum dots suffering from low conductivity and efficiency droop under high current densities, in situ deposited 3D CsPbI films from precursor solutions can maintain high conductivity but show high trap density. Here, it is demonstrated that introducing diammonium iodide can increase the size of colloids in the precursor solution, retard the phase-transition rate, and passivate trap states of the in-situ-formed cuboid crystallites. The PeLED based on the one-step-formed 3D CsPbI cuboid crystallite films shows a peak external quantum efficiency (EQE) value up to 15.03% because of the high conductivity and reduced trap states. Furthermore, this one-step method also has a wide processing window, which is attractive for flow-line production of large-area PeLED modules. The fabrication of a 9 cm PeLED that exhibits a peak EQE of 10.30% is successfully demonstrated.
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http://dx.doi.org/10.1002/adma.202105699DOI Listing
December 2021

Efficient and Stable CsPbI Inorganic Perovskite Photovoltaics Enabled by Crystal Secondary Growth.

Adv Mater 2021 Nov 13;33(44):e2103688. Epub 2021 Sep 13.

School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, 800 Dongchuan Road, Minhang District, Shanghai, 200240, China.

Defect-triggered phase degradation is generally considered as the main issue that causes phase instability and limited device performance for CsPbI inorganic perovskites. Here, a defect compensation in CsPbI perovskite through crystal secondary growth of inorganic perovskites is demonstrated, and highly efficient inorganic photovoltaics are realized. This secondary growth is achieved by a solid-state reaction between a bromine salt and defective CsPbI perovskite. Upon solid-state reaction, the Br ions can diffuse over the entire CsPbI perovskite layer to heal the undercoordinated Pb and conduct certain solid-state I/Br ion exchange reaction, while the organic cations can potentially heal the Cs cation vacancies through coupling with [PbI ] octahedra. The carrier dynamics confirm that this crystal secondary growth can realize defect compensation in CsPbI . The as-achieved defect-compensated CsPbI not only improves the charge dynamics but also enhances the photoactive phase stability. Finally, the CsPbI -based solar cell delivers 20.04% efficiency with excellent operational stability. Overall, this work proposes a novel concept of defect compensation in inorganic perovskites through crystal secondary growth induced by solid-state reaction that is promising for various optoelectronic applications.
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http://dx.doi.org/10.1002/adma.202103688DOI Listing
November 2021

MA Cation-Induced Diffusional Growth of Low-Bandgap FA-Cs Perovskites Driven by Natural Gradient Annealing.

Research (Wash D C) 2021 18;2021:9765106. Epub 2021 Aug 18.

School of Environmental Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240, China.

Low-bandgap formamidinium-cesium (FA-Cs) perovskites of FA Cs PbI ( < 0.1) are promising candidates for efficient and robust perovskite solar cells, but their black-phase crystallization is very sensitive to annealing temperature. Unfortunately, the low heat conductivity of the glass substrate builds up a temperature gradient within from bottom to top and makes the initial annealing temperature of the perovskite film lower than the black-phase crystallization point (~150°C). Herein, we take advantage of such temperature gradient for the diffusional growth of high-quality FA-Cs perovskites by introducing a thermally unstable MA cation, which would firstly form -phase FA-MA-Cs mixed perovskites with low formation energy at the hot bottom of the perovskite films in the early annealing stage. The natural gradient annealing temperature and the thermally unstable MA cation then lead to the bottom-to-top diffusional growth of highly orientated -phase FA-Cs perovskite, which exhibits 10-fold of enhanced crystallinity and reduced trap density (~3.85 × 10 cm). Eventually, such FA-Cs perovskite films were fabricated into stable solar cell devices with champion efficiency up to 23.11%, among the highest efficiency of MA-free perovskite solar cells.
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http://dx.doi.org/10.34133/2021/9765106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8391048PMC
August 2021

Organic Matrix Assisted Low-temperature Crystallization of Black Phase Inorganic Perovskites.

Angew Chem Int Ed Engl 2022 Jan 7;61(1):e202110603. Epub 2021 Oct 7.

School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, China.

All-inorganic perovskites have attracted increasing attention for applications in perovskite solar cells (PSCs) and optoelectronics, including light-emitting devices (LEDs). Cesium lead halide perovskites with tunable I/Br ratios and a band gap aligning with the sunlight region are promising candidates for PSCs. Although impressive progress has been made to improve device efficiency from the initial 2.9 % with low phase stability to over 20 % with high stability, there are still questions regarding the perovskite crystal growth mechanism, especially at low temperatures. In this Minireview, we summarize recent developments in using an organic matrix, including the addition and use of organic ions, polymers, and solvent molecules, for the crystallization of black phase inorganic perovskites at temperatures lower than the phase transition point. We also discuss possible mechanisms for this low-temperature crystallization and their effect on the stability of black phase perovskites. We conclude with an outlook and perspective for further fabrication of large-scale inorganic perovskites for optoelectronic applications.
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http://dx.doi.org/10.1002/anie.202110603DOI Listing
January 2022

Highly Stable Inorganic Lead Halide Perovskite toward Efficient Photovoltaics.

Acc Chem Res 2021 Sep 24;54(17):3452-3461. Epub 2021 Aug 24.

School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China.

ConspectusOwing to the remarkable progress achieved over the past decade with research efforts from the perspectives of material synthesis, device configuration, and theoretical investigation, metal halide perovskites have emerged as a revolutionary class of light-absorbing semiconductors. The perovskite photovoltaic devices have demonstrated an impressive increase in power conversion efficiency. For single-junction perovskite solar cells, the value has risen from the initial one-digit maximum to the state-of-art record of 25.5%. Among various chemical and structural variations of perovskites, inorganic lead halides possess a more favorable operational stability and hold greater potential for perovskite/silicon tandem photovoltaics' top cells. At the initial stage of exploring all-inorganic perovskites for optoelectronic applications, many concepts, technical routes, and modification strategies were directly adopted from research on the more-developed field of organic-inorganic hybrid perovskite (OIHP). However, as understandings on inorganic perovskite deepen with research experience gained from both experimental and theoretical progression, it has been found that the difference between the asymmetric, volatile organic cations and the spherical, stable inorganic cations can lead to drastic changes on overall material properties and the subsequent device performances. In detail, the disparities reflect the crystalline and phase profiles of the material, the fabrication and passivation rationales of perovskite thin films, and the photophysics in the assembled optoelectronic devices. Therefore, the discussions of all-inorganic perovskites have their own exclusivity and are worthy of a specialized scrutinization.Here in this Account, the latest progress on the stabilization of inorganic lead halide perovskites for efficient photovoltaic applications is highlighted. A library of chemical compositions will be discussed with a focus on notable works about CsPbI, which possesses a more favorable bandgap as a tandem to commercialized silicon solar cells. To underscore the influence of the crystal phase on the stability of inorganic perovskites, fundamental investigations regarding the chemical and physical properties, including experimental and theoretical studies, will be summarized as a means of phase control. The stability of inorganic lead halide perovskites can also be improved by the strategic introduction of external components to the light-absorbing layer, such as the incorporation of inorganic halides, organic cations, OIHPs with low dimension, etc. These strategies can synergistically improve the stability and efficiency of the fabricated devices from the perspectives of compositional tuning, dimensional engineering, surface termination, and low-dimension capping. On the basis of a careful examination and an analysis of works achieved in these categories from our group and others, we will then discuss some promising approaches toward achieving more stable and efficient photovoltaics using inorganic lead halide perovskites.
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http://dx.doi.org/10.1021/acs.accounts.1c00343DOI Listing
September 2021

Incorporation of Two-Dimensional WSe into MAPbI Perovskite for Efficient and Stable Photovoltaics.

J Phys Chem Lett 2021 Jul 19;12(29):6883-6888. Epub 2021 Jul 19.

School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China.

Achieving reduced defect density and efficient charge carrier extraction plays a vital role for efficient and stable perovskite solar cells (PSCs). Over the course of technical development, it is desired to use one single material or approach to synergistically passivate defects and enhance the charge extraction. In this work, we developed an effective strategy for obtaining efficient and stable PSCs via incorporating quasi-monolayer two-dimensional WSe into the MAPbI perovskite layer. The addition of WSe helps with the formation of perovskite film with higher quality and also passivates the Pb-related defects through Pb-Se coordination bonding. MAPbI/WSe shows a more matched energy-level alignment between the perovskite layer and hole transport layer for accelerated hole extraction. Consequently, the performances of PSCs significantly improved with power conversion efficiency increase from 19.2% to 21.2% after the incorporation of WSe. Accordingly, the MAPbI/WSe-based PSCs exhibit well-improved photostability with suppression of Pb defect formation.
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http://dx.doi.org/10.1021/acs.jpclett.1c02012DOI Listing
July 2021

Using steric hindrance to manipulate and stabilize metal halide perovskites for optoelectronics.

Chem Sci 2021 May 18;12(21):7231-7247. Epub 2021 May 18.

School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University Shanghai 200240 China

The chemical instability of metal halide perovskite materials can be ascribed to their unique properties of softness, in which the chemical bonding between metal halide octahedral frameworks and cations is the weak ionic and hydrogen bonding as in most perovskite structures. Therefore, various strategies have been developed to stabilize the cations and metal halide frameworks, which include incorporating additives, developing two-dimensional perovskites and perovskite nanocrystals, Recently, the important role of utilizing steric hindrance for stabilizing and passivating perovskites has been demonstrated. In this perspective, we summarize the applications of steric hindrance in manipulating and stabilizing perovskites. We will also discuss how steric hindrance influences the fundamental kinetics of perovskite crystallization and film formation processes. The similarities and differences of the steric hindrance between perovskite solar cells and perovskite light emission diodes are also discussed. In all, utilizing steric hindrance is a promising strategy to manipulate and stabilize metal halide perovskites for optoelectronics.
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http://dx.doi.org/10.1039/d1sc01171eDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8171330PMC
May 2021

Organic Tetrabutylammonium Cation Intercalation to Heal Inorganic CsPbI Perovskite.

Angew Chem Int Ed Engl 2021 May 28;60(22):12351-12355. Epub 2021 Apr 28.

School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, China.

The in situ formation of reduced dimensional perovskite layer via post-synthesis ion exchange has been an effective way of passivating organic-inorganic hybrid perovskites. In contrast, cesium ions in Cs-based inorganic perovskite with strong ionic binding energy cannot exchange with those well-known organic cations to form reduced dimensional perovskite. Herein, we demonstrate that tetrabutylammonium (TBA ) cation can intercalate into CsPbI to effectively substitute the Cs cation and to form one-dimensional (1D) TBAPbI layer in the post-synthesis TBAI treatment. Such TBA cation intercalation leads to in situ formation of TBAPbI protective layer to heal defects at the surface of inorganic CsPbI perovskite. The TBAPbI -CsPbI perovskite exhibited enhanced stability and lower defect density, and the corresponding perovskite solar cell devices achieved an improved efficiency up to 18.32 % compared to 15.85 % of the control one.
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http://dx.doi.org/10.1002/anie.202102538DOI Listing
May 2021

Chemically Stable Black Phase CsPbI Inorganic Perovskites for High-Efficiency Photovoltaics.

Adv Mater 2020 Nov 22;32(45):e2001025. Epub 2020 Sep 22.

School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai, 200240, China.

Research on chemically stable inorganic perovskites has achieved rapid progress in terms of high efficiency exceeding 19% and high thermal stabilities, making it one of the most promising candidates for thermodynamically stable and high-efficiency perovskite solar cells. Among those inorganic perovskites, CsPbI with good chemical components stability possesses the suitable bandgap (≈1.7 eV) for single-junction and tandem solar cells. Comparing to the anisotropic organic cations, the isotropic cesium cation without hydrogen bond and cation orientation renders CsPbI exhibit unique optoelectronic properties. However, the unideal tolerance factor of CsPbI induces the challenges of different crystal phase competition and room temperature phase stability. Herein, the latest important developments regarding understanding of the crystal structure and phase of CsPbI perovskite are presented. The development of various solution chemistry approaches for depositing high-quality phase-pure CsPbI perovskite is summarized. Furthermore, some important phase stabilization strategies for black phase CsPbI are discussed. The latest experimental and theoretical studies on the fundamental physical properties of photoactive phase CsPbI have deepened the understanding of inorganic perovskites. The future development and research directions toward achieving highly stable CsPbI materials will further advance inorganic perovskite for highly stable and efficient photovoltaics.
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http://dx.doi.org/10.1002/adma.202001025DOI Listing
November 2020

5-Ammonium Valeric Acid Iodide to Stabilize MAPbI via a Mixed-Cation Perovskite with Reduced Dimension.

J Phys Chem Lett 2020 Oct 15;11(19):8170-8176. Epub 2020 Sep 15.

School of Environmental Science and Engineering, Frontiers Science Center for Transformative Molecules, Shanghai Jiao Tong University, Shanghai 200240, China.

5-Ammonium valeric acid iodide (AVAI) has been widely known as a stabilizer to enhance the stability of MAPbI perovskite, but its role and function is still under exploration. The typical 2D perovskites of AVAPbI have been proposed as the capping layer for stabilization. Here, a novel AVA-MA mixed-cation perovskite of AVAMAPbI is found to show a more even and compact coverage than the typical 2D perovskite of AVAPbI. A simple post-treatment on MAPbI films by using AVAI isopropanol solution can fabricate such a mixed-cation 2D perovskite capping layer on the MAPbI sample. This AVAMAPbI capping layer effectively passivates surface defects of MAPbI perovskite films and reduces the charge-carrier recombination, enabling AVAI-MAPbI perovskite films to exhibit improved stability against thermal and moisture stress. Finally, the AVAI-MAPbI-based perovskite solar cells also show an enhanced photovoltaic performance with a champion PCE up to 20.05% with enhanced stability.
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http://dx.doi.org/10.1021/acs.jpclett.0c02528DOI Listing
October 2020

NIST Interlaboratory Study on Glycosylation Analysis of Monoclonal Antibodies: Comparison of Results from Diverse Analytical Methods.

Mol Cell Proteomics 2020 01 7;19(1):11-30. Epub 2019 Oct 7.

Graduate School of Analytical Science and Technology, Chungnam National University, Gung-dong 220, Yuseong-Gu, Daejeon 305-764, Korea (South).

Glycosylation is a topic of intense current interest in the development of biopharmaceuticals because it is related to drug safety and efficacy. This work describes results of an interlaboratory study on the glycosylation of the Primary Sample (PS) of NISTmAb, a monoclonal antibody reference material. Seventy-six laboratories from industry, university, research, government, and hospital sectors in Europe, North America, Asia, and Australia submitted a total of 103 reports on glycan distributions. The principal objective of this study was to report and compare results for the full range of analytical methods presently used in the glycosylation analysis of mAbs. Therefore, participation was unrestricted, with laboratories choosing their own measurement techniques. Protein glycosylation was determined in various ways, including at the level of intact mAb, protein fragments, glycopeptides, or released glycans, using a wide variety of methods for derivatization, separation, identification, and quantification. Consequently, the diversity of results was enormous, with the number of glycan compositions identified by each laboratory ranging from 4 to 48. In total, one hundred sixteen glycan compositions were reported, of which 57 compositions could be assigned consensus abundance values. These consensus medians provide community-derived values for NISTmAb PS. Agreement with the consensus medians did not depend on the specific method or laboratory type. The study provides a view of the current state-of-the-art for biologic glycosylation measurement and suggests a clear need for harmonization of glycosylation analysis methods.
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http://dx.doi.org/10.1074/mcp.RA119.001677DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6944243PMC
January 2020

Impact of Pluronic F68 on hollow fiber filter-based perfusion culture performance.

Bioprocess Biosyst Eng 2017 Sep 2;40(9):1317-1326. Epub 2017 Jun 2.

Upstream Process Development & Engineering, Biologics Process Development & Clinical Manufacturing, Merck & Co., Inc., 2000 Galloping Hill Road, Kenilworth, NJ, 07033, USA.

High cell density is an important factor in achieving high bioreactor productivity. To meet the oxygen demand with density at >100 × 10 cells/mL, a frit sparger is often used. In this study, the impact of Pluronic F68 on a perfusion process using a frit sparger was studied. The perfusion process was developed using an alternating tangential flow device with a 0.2 µm PES hollow fiber filter. Pluronic F68 at 2 g/L was sufficient in preventing cell damage at gas flow rate of ~0.20 vvm from a drilled hole sparger (0.5 mm) but inadequate at ~0.025 vvm from a frit sparger (20 µm). Increase of Pluronic F68 concentration to 5 g/L prevented cell death at up to ~0.10 vvm from the frit sparger and was able to maintain high cell density at high viability in the range of 60-80 × 10 cells/mL. Such positive effect was demonstrated in both 3- and 200-L bioreactors. Supplementing additional Pluronic F68 was also effective in restoring cell growth/viability from low viability cultures. Increased Pluronic F68 concentration had no adverse impact on target antibody, HCP, and Pluronic F68 transmissions.
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http://dx.doi.org/10.1007/s00449-017-1790-2DOI Listing
September 2017

Identification of Low Abundant Isomeric N-Glycan Structures in Biological Therapeutics by LC/MS.

Anal Chem 2016 07 27;88(14):7049-59. Epub 2016 Jun 27.

BioAnalytix, Inc., Cambridge, Massachusetts 02139, United States.

An effective LC-MS based method for online characterization of low abundant structural isomers of N-linked glycans in biological therapeutics was developed. N-linked glycans of a recombinant monoclonal antibody were released by PNGase F and labeled with 2-aminobenzamide (2-AB) fluorescent tag. The labeled glycans were analyzed by online ultraperformance liquid chromatography-hydrophilic interaction liquid chromatography (UPLC-HILIC) coupled with mass spectrometry (MS). The glycan structure was characterized by MS(n) fragmentation in negative ion mode followed by identification of the signature D ions. The assignment included monosaccharide sequence and linkage information. The developed method successfully characterized structural isomers of A1G1F (assigned as terminal sialic acid attached in the 1,6 branch at 2,3 position), and A1G1F' (assigned as terminal sialic acid attached in the 1,3 branch at 2,3 position). Moreover, using the same approach, previously unknown low abundant species were identified unambiguously. One such structural isomer at low level, terminal GlcNAc of G1F+GlcNAc, was identified to be linked at the 1,6 branch. Additionally, another low level structural isomer, previously assigned as Man8 glycan, was found to be Man7+Glc glycan as its 1,3 branch containing three mannoses and one terminal glucose. The identification was further confirmed by a purified α-1,2-endomannosidase enzyme to generate the cleavage of α-1,3 linked terminal disaccharides (Man+glucose). Using this approach, different lots or different CHO produced mAbs was thoroughly examined and found that the newly identified "Man8" (Man7+Glc) was also present in different batches and in some commercially available therapeutic mAbs.
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http://dx.doi.org/10.1021/acs.analchem.6b00636DOI Listing
July 2016

Ultrafast and high-throughput N-glycan analysis for monoclonal antibodies.

MAbs 2016 May-Jun;8(4):706-17. Epub 2016 Apr 15.

a Bioprocess Development, Merck Research Laboratories, Merck & Co., Inc. , Kenilworth , USA.

Glycosylation is a critical attribute for development and manufacturing of therapeutic monoclonal antibodies (mAbs) in the pharmaceutical industry. Conventional antibody glycan analysis is usually achieved by the 2-aminobenzamide (2-AB) hydrophilic interaction liquid chromatography (HILIC) method following the release of glycans. Although this method produces satisfactory results, it has limited use for screening a large number of samples because it requires expensive reagents and takes several hours or even days for the sample preparation. A simple and rapid glycan analysis method was not available. To overcome these constraints, we developed and compared 2 ultrafast methods for antibody glycan analysis (UMAG) that involve the rapid generation and purification of glycopeptides in either organic solvent or aqueous buffer followed by label-free quantification using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Both methods quickly yield N-glycan profiles of test antibodies similar to those obtained by the 2-AB HILIC-HPLC method. In addition, the UMAG method performed in aqueous buffer has a shorter assay time of less than 15 min, and enables high throughput analysis in 96-well PCR plates with minimal sample handling. This method, the fastest, and simplest as reported thus far, has been evaluated for glycoprofiling of mAbs expressed under various cell culture conditions, as well as for the evaluation of antibody culture clones and various production batches. Importantly the method sensitively captured changes in glycoprofiles detected by traditional 2-AB HILIC-HPLC or HILIC-UPLC. The simplicity, high speed, and low cost of this method may facilitate basic research and process development for novel mAbs and biosimilar products.
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http://dx.doi.org/10.1080/19420862.2016.1156828DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4966838PMC
November 2017

Assessment of p53 gene transfer and biological activities in a clinical study of adenovirus-p53 gene therapy for recurrent ovarian cancer.

Cancer Gene Ther 2003 Mar;10(3):224-38

Canji, Inc., San Diego, California 92121, USA.

A cohort study was designed to evaluate the efficiency of gene transfer and whether biological activity from the expressed therapeutic gene resulted after administration of a recombinant adenovirus containing the human wild-type p53 (p53(wt)) gene (rAd-p53 SCH 58500). The cohort study was conducted in five trial subjects with recurrent ovarian cancer. Each trial subject received multiple cycles of rAd-p53 SCH 58500, each cycle comprised of doses of 7.5 x 10(13) particles on each of five consecutive days. Subjects were treated with rAd-p53 SCH 58500 alone during Cycle 1 and in combination with gemcitabine during the subsequent cycles. Both tumor biopsies and peritoneal aspirates were collected and evaluated for gene transfer and evidence of the biological activities of the expressed p53(wt) gene. Using quantitative PCR and RT-PCR, and in situ PCR, gene transfer and expression were documented in tumor biopsies (four of five patients) collected from Cycle 1. Furthermore, upregulation of p21/WAF1, bax and mdm-2, and downregulation of survivin were observed in these same tumor biopsy samples, suggesting that intraperitoneal administration of rAd-p53 SCH 58500 leads to detectable p53 biological activity in target tumor tissue. In addition, gene transfer and its expression were observed in cells obtained from peritoneal aspirates. These fluids were mainly comprised of polymorphonuclear neutrophils, indicating that successful gene transfer can be achieved by multiple cycle intraperitoneal administration of recombinant adenovirus.
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http://dx.doi.org/10.1038/sj.cgt.7700562DOI Listing
March 2003

Central nervous system inflammation and neurological disease in transgenic mice expressing the CC chemokine CCL21 in oligodendrocytes.

J Immunol 2002 Feb;168(3):1009-17

Department of Immunology, Schering-Plough Research Institute, Kenilworth, NJ 07033, USA.

To study the biological role of the chemokine ligands CCL19 and CCL21, we generated transgenic mice expressing either gene in oligodendrocytes of the CNS. While all transgenic mice expressing CCL19 in the CNS developed normally, most (18 of 26) of the CCL21 founder mice developed a neurological disease that was characterized by loss of landing reflex, tremor, and ataxia. These neurological signs were observed as early as postnatal day 9 and were associated with weight loss and death during the first 4 wk of life. Microscopic examination of the brain and spinal cord of CCL21 transgenic mice revealed scattered leukocytic infiltrates that consisted primarily of neutrophils and eosinophils. Additional findings included hypomyelination, spongiform myelinopathy with evidence of myelin breakdown, and reactive gliosis. Thus, ectopic expression of the CC chemokine CCL21, but not CCL19, induced a significant inflammatory response in the CNS. However, neither chemokine was sufficient to recruit lymphocytes into the CNS. These observations are in striking contrast to the reported activities of these molecules in vitro and may indicate specific requirements for their biological activity in vivo.
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http://dx.doi.org/10.4049/jimmunol.168.3.1009DOI Listing
February 2002
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