Flow-through Process Research Articles

In silico mediated workflow for rapid development of downstream processing: Orthogonal product-related impurity removal for a Fc-containing therapeutic

Therapeutic formats derived from the monoclonal antibody structure have been gaining significant traction in the biopharmaceutical market. Being structurally similar to mAbs, most Fc-containing therapeutics exhibit product-related impurities in the form of aggregates, charge variants, fragments, and glycoforms, which are inherently challenging to remove. In this work, we developed a workflow that employed rapid resin screening in conjunction with an in silico tool to identify and rank orthogonally selective processes for the removal of product-related impurities from a Fc-containing therapeutic product. Linear salt gradient screens were performed at various pH conditions on a set of ion-exchange, multimodal ion-exchange, and hydrophobic interaction resins. Select fractions from the screening experiments were analyzed by three different analytical techniques to characterize aggregates, charge variants, fragments, and glycoforms. The retention database generated by the resin screens and subsequent impurity characterization were then processed by an in silico tool that generated and ranked all possible two-step resin sequences for the removal of product-related impurities. A highly-ranked process was then evaluated and refined at the bench-scale to develop a completely flowthrough two-step polishing process which resulted in complete removal of the Man5 glycoform and aggregate impurities with a 73% overall yield. The successful implementation of the in silico mediated workflow suggests the possibility of a platformable workflow that could facilitate polishing process development for a wide variety of mAb-based therapeutics.

Effect of Microplastics on the Flow-Through Electro-Peroxone Process: A Computational Fluid Dynamics Simulation

Effect of Microplastics on the Flow-Through Electro-Peroxone Process: A Computational Fluid Dynamics Simulation

Degradation of Atrazine by Flow-Through UV-Based Advanced Oxidation Processes: Roles of Light Source and Chlorine Addition

Understanding the degradation kinetics and mechanisms of trace organic contaminants (TrOCs) by UV-based advanced oxidation processes (UV-AOPs) are pivotal in realizing their efficient application in water treatment. However, the relevant knowledge in practical flow-through reactors remains a void, compared with that of commonly used batch reactors. To fill the knowledge gaps, the current work investigated the degradation of atrazine (ATZ) in flow-through UV-AOP systems with different light sources and chlorine additions. The results showed that UV/Cl2 in the reactors (with a diameter of 50 mm) was not very efficient in ATZ degradation while the pseudo-first order degradation rate constant was elevated by over 2.7 times with vacuum UV (VUV)/UV. In contrast to observations in the batch reactors, the addition of chlorine to the flow-through VUV/UV system unexpectedly decreased the rate constant by about 39%. The analysis of the relative contributions of different degradation pathways revealed that the inhibitory effect of the chlorine addition arose from the transformation of HO• to reactive chlorine species (e.g., ClO•) which had low reaction rate constants with ATZ. The baffle implementation promoted the ATZ degradation by 12–58%, mainly due to an enhanced mixing that facilitated the radical oxidation. The energy costs of the UV-AOPs in ATZ removal ranged within 0.40–1.11 kWh m−3 order−1. The findings of this work are helpful in guiding efficient VUV/UV and VUV/UV/Cl2 processes in drinking water treatment.

Energy-efficient treatment of refractory industrial effluent using flow-through electrochemical processes: Oxidation mechanisms and reduction of chlorinated byproducts

While flow-through anodic oxidation (FTAO) technique has demonstrated high efficiency to treat various refractory waste streams, there is an increasing concern on the secondary hazard generation thereby. In this study, we developed an integrated system that couples FTAO and cathodic reduction processes (termed FTAO-CR) for sustainable treatment of chlorine-laden industrial wastewater. Among four common electrode materials (i.e., Ti4O7, β-PbO2, RuO2, and SnO2-Sb), RuO2 flow-through anode exhibited the best pollutant removal performance and relatively low ClO3 and ClO4 yields. Because of the significant scavenging effect of Cl− in real wastewater treatment, the direct electron transfer process played a dominant role in contaminant degradation for both active and nonactive anodes though active species (i.e., active chlorine) were involved in the subsequent transformation of the organic matter. A continuous FTAO-CR system was then constructed for simultaneous COD removal and organic and inorganic chlorinated byproduct control. The quality of the treated effluent could meet the national discharge permit limit at low energy cost (∼4.52 kWh m3 or ∼0.035 kWh g1-COD). Results from our study pave the way for developing novel electrochemical platforms for the purification of refractory waste streams whilst minimizing the secondary pollution.

Biopolyphenol stabilized CoFe2O4-rGO/GO catalytic cleaning membrane for fast and high-efficiency contaminants removal

Utilizing membrane materials for the purification of wastewater represents an effective approach to address water scarcity. Nonetheless, the issues of membrane fouling and stability hinder their widespread application. Herein, an effective biopolyphenols (PP) modification strategy was proposed to construct strongly stable cobalt ferrite-loaded graphene oxide (CoFe2O4-rGO-PP/GO) membranes with catalytic cleaning function. Compared with the membranes without PP modification, the incorporation of polymerized tannic acid (pTA), green tea polyphenol (GTP), and black tea polyphenol (BTP) significantly improved membrane separation efficiencies of methylene blue (MB), with high removal reaching 99.11, 98.92, and 99.20 %, respectively. Notably, the CoFe2O4-rGO-pTA/GO membrane demonstrated high rejection and outstanding permeability of 167.2 L m−2 h−1 bar−1. Introducing pTA, GTP, and BTP could enhance MB degradation rate constants by 61.54, 38.46, and 19.23 % via peroxymonosulfate (PMS) activation, respectively. Remarkably, CoFe2O4-rGO-pTA/GO membrane achieved near-complete MB degradation within 12 min. Moreover, CoFe2O4-rGO-PP/GO membranes maintained high MB rejection exceeding 97 % even after ten cycles, highlighting exceptional stability and catalytic cleaning performance. The separation mechanism of these membranes was dominantly governed by the nano-confined adsorption under pressure-driven flow-through process, which was greatly distinguished from a size-sieving mechanism of densely stacked 2D lamellar membranes replying on their in-plane pores or interlayer nano/subnano-channels. This PP modification strategy can be extended to design diversified 2D lamellar membranes with guest intercalation, to achieve high stability, superior separation and multi-function.

Electrochemical oxidation of methyl blue dye by stainless steel tubes bundle anode

Methyl blue dye was successfully electrochemically oxidised in a flow-through batch circulation process using a stainless-steel tube bundle anode. The experimental design and process optimisation were conducted according to the response surface Methodology with Rotatable Central Composite Design method. The controlled variables in this study were the solution flow rate, applied current, electrolyte concentration, and time. A quadratic mathematical model expressing the removal percentage as a function of the operating variables and their interactions was constructed from the experimental data. The accuracy of the model was confirmed using residual plots and an R2 value of 0.8526. Solution flow rate was found to promote the removal percentage up to 1.5 l/min, the applied current promoted the removal efficiency significantly up to 400 mA, the electrolyte concentration had a positive effect up to 2 M, and the removal efficiency increases generally with time, reaching the equilibrium removal percentage at 67.121 min. The optimum conditions for the target with the highest removal percentage of 91.333% were found to be 1.5 l/min solution flow rate, 400 mA applied current, 2 M electrolyte solution, and 67.121 min.

Chemically robust functionalized covalent organic framework for the highly efficient and selective separation of bromine.

Effective sequestration of bromine holds great promise for the chemical industry's safe expansion, environmental preservation, and public health. However, attaining this goal is still challenging due to the serious drawbacks of existing adsorbents such as limited capacity, low retention efficiency, and sluggish uptake kinetics. Herein, we report a strategy-driven systematic study aimed at significantly enhancing multiple host-guest interactions to obtain functionalized covalent-organic frameworks for the efficient sequestration of bromine. Results showed that the presence of specific quantities of selective binding sites of the porous frameworks afford stronger host-guest interactions and therefore higher bromine adsorption capacities. The developed framework exhibits high bromine sorption capacity of up to 5.16 g g-1 in the vapor phase and 8.79 g g-1 in the aqueous phase under static adsorption conditions with fast kinetics, large distribution coefficient (Kd ∼105 mL g-1), high retention efficiency and reusability. Moreover, the adsorbent is able to sequestrate trace bromine (from 13 ppm to below 4 ppm) from aqueous medium with fast adsorption kinetics (86.3% within less than 3 h) and demonstrates the selective extraction of bromine over iodine under both static and dynamic conditions. These results were further utilized to demonstrate recycling-selective and highly efficient bromine capture from a real-water system, exhibiting excellent scalability and affordability, as exemplified using COF membranes in a continuous flow-through process.

Integrated physicochemical processes to tackle high-COD wastewater from pharmaceutical industry

Wastewater decontamination in pharmaceuticals is crucial to prevent environmental and health risks from API residues and other contaminants. Advanced oxidation processes (AOPs) combined with cavitational treatments offer effective solutions. Challenges include designing reactors on a large scale and monitoring the effectiveness and synergies of the hybrid technology. In the present work, pilot-scale treatment of a real high COD (485 g/L) pharmaceutical wastewater (PW) was investigated using hydrodynamic cavitation (HC) operated individually at 330 L/h or in combination with oxidants and electrical discharge (ED) with cold plasma (15 kV and 48 kHz). The first approach consisted of PW cavitational treatment alone of 7 L of 1:100 diluted PW at a HC-induced pressure of 60 bar and a flow rate of 330 L/h. However, this strategy did not provide satisfactory results for COD (∼15% less), and only when HC treatment was extended to more than 30 min in a recirculation mode, encouraging results were obtained (∼45% COD reduction). Consequently, a hybrid approach combining HC with ED-cold plasma was chosen to treat this high-COD PW. Aiming to establish an efficient flow-through hybrid process, after optimising all cavitation and electrical discharge parameters (45 bar HC pressure and 10 kHz ED frequency), the best COD abatement of ∼50 % was recorded with a 1:50 diluted PW. However, a subsequent adsorption step over activated carbon was required to achieve an almost quantitative COD reduction (95%+). Our integrated physicochemical process proved to be extremely efficient in treating high-COD industrial wastewater and resulted in a remarkable reduction of the COD value. In addition, the residual surfactants content in the PW were also drastically reduced (98%+) when a small amount of oxidants was added in the hybrid HC/ED treatment.

Photothermal synergistic effect of Ti3C2Tx/ZnIn2S4 Schottky junction for efficient inactivation of antibiotic-resistant bacteria and genes: Mechanism discussion and practical application

Antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) in wastewater pose a significant threat to public health. Photothermal synergistic catalysis has the great potential to effectively mitigate ARB and ARG pollution. Herein, we design a Ti3C2Tx/ZnIn2S4 (Ti3C2Tx/ZIS) Schottky junction with photothermal effect by exploiting the contact potential difference between Ti3C2Tx and ZnIn2S4. The experimental results and DFT calculations demonstrate that the Schottky barrier inhibits electron backflow, thereby enhancing the photodynamic properties of Ti3C2Tx/ZIS. The photothermal heating effect, induced by the localized surface plasmon resonance (LSPR) of Ti3C2Tx, further enhances ROS production via facilitating charge transfer. Profiting from the photothermal synergistic effect, Ti3C2Tx/ZIS can completely inactivate ARB within 25 min and degrade 5-log ARG within 120 min under vis-NIR light irradiation. The Ti3C2Tx/ZIS demonstrated its potential for practical wastewater treatment in a flow-through reactor process, achieving 4-log bacteria inactivation and 99.7% ARG removal from secondary effluent after continuous operation for 8 h.

Facile synthesis of bimetallic ACF/CC@FeOCl–Cu composite cathode for efficient degradation of sulfamethoxazole at neutral pH by a flow-through heterogeneous electro-Fenton process

Flow-through heterogeneous electro-Fenton (FHEF) process shows a broad prospect for refractory organic pollutants removal. However, maintaining a long-term service life of higher catalytic cathode is crucial for the development of cathode materials, especially for iron-functionalized cathode operated under harsh conditions. In this study, a novel bimetallic CC@FeOCl–Cu composite was synthesized through one-step calcination, coupled with a series of microstructure characterization methodology, including XRD, SEM-EDS, XPS, and FTIR. The superior catalytic activity of CC@FeOCl–Cu could be ascribed to Fe–Cu synergy and better dispersion of FeOCl nanosheets. With the optimal Cu:Fe ratio of 1:60, the bifunctional ACF/CC@FeOCl–Cu cathode was employed in FHEF process, exhibiting an outstanding performance for sulfamethoxazole (SMX) removal over a wide pH range (3.0–9.0). Comparison of experimental results indicated that the ACF/CC@FeOCl–Cu-FHEF process showed higher performance than ACF/CC@FeOCl-FHEF and homogeneous EF processes. The average SMX removal efficiency was 98% and TOC removal efficiency was more than 57% even after 10 cycles. Radical quenching experiments and electron spin resonance test confirmed that •OH was the primary active species. More •OH was generated in the ACF/CC@FeOCl–Cu-FHEF process because the doping of Cu could enhance catalytic activity of cathode. In addition, the satisfactory performance could be observed in the ACF/CC@FeOCl–Cu-FHEF process for the treatment of real landfill leachate, indicating its potential for practical application in wastewater treatment.

Mass Transfer-Promoted Fe2+/Fe3+ Circulation Steered by 3D Flow-Through Co-Catalyst System Toward Sustainable Advanced Oxidation Processes

Realizing fast and continuous generation of reactive oxygen species (ROSs) via iron-based advanced oxidation processes (AOPs) is significant in the environmental and biological fields. However, current AOPs assisted by co-catalysts still suffer from the poor mass/electron transfer and non-durable promotion effect, giving rise to the sluggish Fe2+/Fe3+ cycle and low dynamic concentration of Fe2+ for ROS production. Herein, we present a three-dimensional (3D) macroscale co-catalyst functionalized with molybdenum disulfide (MoS2) to achieve ultra-efficient Fe2+ regeneration (equilibrium Fe2+ ratio of 82.4%) and remarkable stability (more than 20 cycles) via a circulating flow-through process. Unlike the conventional batch-type reactor, experiments and computational fluid dynamics simulations demonstrate that the optimal utilization of the 3D active area under the flow-through mode, initiated by the convection-enhanced mass/charge transfer for Fe2+ reduction and then strengthened by MoS2-induced flow rotation for sufficient reactant mixing, is crucial for oxidant activation and subsequent ROS generation. Strikingly, the flow-through co-catalytic system with superwetting capabilities can even tackle the intricate oily wastewater stabilized by different surfactants without the loss of pollutant degradation efficiency. Our findings highlight an innovative co-catalyst system design to expand the applicability of AOPs based technology, especially in large-scale complex wastewater treatment.

Efficient degradation of carbamazepine using a modified nickel-foam cathode (Ni-FM/CNTs) in penetrating electro-Fenton process

A modified nickel-foam (Ni-FM) cathode coated with multi-walled carbon nanotubes (Ni-FM/CNTs) was synthesized for carbamazepine (CBZ) highly energy-efficient degradation in penetrating electro-Fenton. Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD) test proves that multi-walled CNTs were successfully coated on the surface of nickel foam. The linear sweep voltammetry (LSV) results revealed the greater electrochemical activity of Ni-FM/CNTs compared to Ni-FM. The H2O2 accumulation performance tests showed that Ni-FM/CNTs cathode had higher H2O2 accumulation performance than Ni-FM cathode, and the H2O2 yield of Ni-FM/CNTs was 5.7 times higher than that of Ni-FM after 1 h of electrolysis. The reaction rate of CBZ degradation in penetrating electro-Fenton process was 2.5 times that of planar electro-Fenton process because the flow-through process enhanced O2 mass transfer and promoted the production of H2O2. The Box-Behnken Design response surface method was used to analyze the factors affecting the degradation efficiency of CBZ in the penetrating electro-Fenton process. The CBZ degradation efficiency could reach 100%, and electric energy consumption was 0.4356 Wh/L at current density of 9 mA/cm2, pH = 3, concentration of Fe2+ was 0.3 mM, and the through-flow velocity of 60 mL/min. The quenching experiment and EPR test results confirmed the degradation of CBZ was mainly the oxidation of·OH, and O2-·is the prerequisite for the production of·OH. Eight possible degradation products of CBZ degradation were identified and the probable degradation route was proposed. The ECOSAR program was used to predict the toxicities of CBZ and its degradation products, and the consequences revealed that the electro-Fenton process has a detoxification effect on CBZ, but may also produce more toxic organic compounds than the parent compound.

A Self-cleaning Fe(III)-doped Graphene Oxide Membrane for Emulsion Separation

High hydrophilicity, single-atom thickness and strong coordination properties of graphene oxide (GO) were utilized to create a multifunctional membrane for separation of oil-in-water emulsions. The new Fe(III)-doped GO membrane possessed the superwetting property of GO and Fe(III) catalytic sites for H2O2 activization promoted oxidative degradation of organic fouling agents. It was shown that the self-cleaning membrane can be utilized in a high-throughput flow through system for remediation of contaminated water. High hydrophilicity, single-atom thickness and strong coordination properties of graphene oxide (GO) are utilized to create a multifunctional membrane for emulsion separation. The new Fe(III)-doped GO membrane possesses Fe(III) catalytic sites for H2O2 activization promoted oxidative degradation of organic fouling agents and can be used for wastewater treatment in a continuous flow-through process.

Freestanding catalytic membranes assembled from blade-shaped Prussian blue analog sheets for flow-through degradation of antibiotic pollutants

Membrane catalysis is a frontier technology for effectively removing organic containments, and burgeoning membranes assembled from two-dimensional (2D) materials have significantly flourished in peroxymonosulfate (PMS)-based catalytic membrane processes. Here, a bottom-up strategy based on restricting CoFe Prussian blue analog (PBA) crystal growth in one direction is used to fabricate large-scale 2D blade-shaped PBA sheets, whose radial size and thickness can be adjusted by the precursor ion ratio (CoII/FeII). The stripe CoFe PBA sheets can directly serve as building blocks and are simply assembled into a free-standing 2D membrane by interweaving assembly. The assembled CoFe PBA catalytic membrane possesses excellent wetting properties, guaranteeing an unimpeded mass transfer process, which leads to a superior instantaneous catalytic performance for the antibiotic norfloxacin during the continuous and flow-through membrane catalytic process. SO4•− and 1O2 are demonstrated to be the main active species, which synergistically contribute to the PMS-driven organic degradation.

Mechanisms of interfacial catalysis and mass transfer in a flow-through electro-peroxone process

To investigate the catalytic mechanism and mass transfer efficiency in the removal of amitriptyline using an electro-peroxide process, a CuFe2O4-modified carbon cloth cathode was prepared and utilized in a reaction unit. The results demonstrated a remarkable efficacy of the system, achieving 91.0% amitriptyline removal, 68.3% mineralization, 41.2% mineralization current efficiency, and 0.24 kWh/m3 energy consumption within just five minutes of treatment. The study revealed that the exposed Fe atoms of the ferrite nanoparticles, with a size of 22.7 nm and 89.7% crystallinity, functioned as mediators to bind the adsorbed O atoms. The 3dxy, 3dxz, and 3d2z orbitals of Fe atoms interacted with the 2pz orbital of O atoms of H2O2 and O3 to form σ and π bonds, facilitating the adsorption-activation of H2O2 and O3 into hydroxyl radicals. These hydroxyl radicals (∼ 1.15 × 1013 mol/L) were distributed at the cathode-solution interface and rapidly consumed along the direction of liquid flow. The flow-through cathode design improved the mass transfer of aqueous O3 and in-situ generated H2O2, leading to an increased yield of hydroxyl radicals, as well as the contact time and space between hydroxyl radicals and amitriptyline. Ultimately, this resulted in a higher degradation efficiency of the system.

Novel self-sustained flow-through electrochemical advanced oxidation processes using nano-Fe0 confined B, N co-doped carbon nanotubes/graphite felt cathode: Higher mineralization efficiency under wider pH

To improve the mineralization efficiency of pollutants under wide pH ranges by self-sustained electrochemical advanced oxidation processes (EAOPs) without any reagent addition, a flow-through system based on the bifunctional cathode of B, N-doped carbon nanotubes embedded with nano-Fe0 particles that loaded on graphite felt (Fe@BN-C/GF) was developed. Dominant by 1O2 oxidation, the sulfamethazine (SMT) degradation rate and TOC removal in this recirculated flow-through system were 2.6 ∼ 3.3-folds and 1.4 ∼ 2.4-folds that of the batch system under the pH ranges of 3 ∼ 11, respectively. The SMT degradation performance was found not affected in the presence of HCO3–, NO3–, Cl-, K+, or humic acid (HA). The Fe@BN-C/GF cathode had more potential to treat enlarged wastewater by 5-folds during 10 h operation, and the SMT and TOC removal was 99% and 70.31%, respectively. The total phosphorus (TP), ammonia nitrogen (NH3-N) and TOC in reverse osmosis concentrate and secondary wastewater effluent could be simultaneously removed to <0.01 mg L-1 and 8 mg L-1 by this flow-through system with a low electric energy consumption (EEC) of 0.022 and 0.18 kWh gTOC-1, respectively. This EAOPs based on the flow-through Fe@BN-C/GF cathode was self-sustained, and had very promising application prospect of high mineralization of pollutants even for low-conductivity wastewater.

Biomass derived S, N self-doped catalytic Janus cathode for flow-through metal-free electrochemical advanced oxidation process: Better removal efficiency and lower energy consumption under neutral conditions

Facing low treatment efficiency, narrow adaptive pH and high energy consumption in electro-Fenton (EF), we proposed a novel flow-through metal-free electrochemical advanced oxidation processes (EAOPs) using biomass derived S, N self-doped catalytic Janus cathode named SNJC. The SNJC was composed of a hydrophobic gas diffusion layer in the middle and hydrophilic catalytic membrane at both ends, while the catalytic membrane of S, N self-doped biomass carbon named SN-BC was derived from waste ginkgo leaves without additional supporting templates or activation processes. The conversion of graphite N, pyridinic N and thiophene S in SN-BC played a significant role in efficient oxygen reduction reaction (ORR) for H2O2 generation and in-situ active species generation. The efficient enrichment and rapid degradation of pollutants in catalytic membrane achieved almost complete removal of tetracycline within 120 min with a low energy consumption of 16.8 kWh/kg TOC. This flow-through system exhibited superior catalytic performance in wide pH ranges (3–11) due to the collective effect of radicals (•OH and O2•−) and non-radical (1O2). This work provides a new insight towards the design of S, N self-doped Janus electrode and activation mechanism of in-situ generation and metal-free catalysis of H2O2 in flow-through EAOPs.

A flow-through strategy using supported ionic liquids for L-asparaginase purification

L-asparaginase (ASNase) is an amidohydrolase enzyme widely distributed in nature, e.g., microorganisms, plants and tissues of several animals. Nevertheless, microorganisms are the preferential source of ASNase since they usually grow in simple substrates and culture conditions. However, a high level of enzyme purity is required by the pharmaceutical industry, in which the applied downstream process may account for up to 80% of the total ASNase production costs. Silica-based supported ionic liquid-like phase (SSILLP) materials are here proposed as alternative immobilization/capture or processing supports for the ASNase purification. SSILLP materials with different alkyl chain lengths at the cation source and Cl− as the counterion were investigated to purify ASNase by the flow-through like mode. Silica functionalized with dimethylbutylpropylammonium chloride ([Si][N3114]Cl) was selected as the most promising material since it displayed the highest purification factor (1.65) and specific activity of ASNase (0.026 U mg−1) achieved. The ASNase purification operating conditions were then optimized through Response Surface Methodology, using pH (range in which enzyme is active) and solid/liquid ratio (S/L ratio) as factors, achieving a maximum purification factor of 3.36. Semi-continuous purification of ASNase was finally performed under the optimized purification conditions (pH 3 and S/L ratio of 15), enabling a purification factor of 5.15. This corresponds to a 3.12- and a 1.53-fold increase in the purification factor obtained compared with the initial screening and batch assays under optimized purification conditions. These findings demonstrate that SSILLP materials can act as simple semi-continuous ASNase purification supports with potential in flow-through downstream processing.

Enhanced electrochemiluminescence immunoassay: 2. Enabling signal detection at an early stage of incubation for rapid point-of-care testing

Signal detection in a label-based immunoassay is performed normally when the antigen/antibody binding reaction reaches the equilibrium state during the incubation period of an assay process. Shortening the incubation period in an assay helps reduce the turnaround time and is particularly valuable for point-of-care testing, but the cost is the reduction of signal level and, possibly, measurement precision as well. This work demonstrates that the signal loss could be offset by the stronger emission of an electronically neutral ruthenium(II) complex label, Ru(2, 2′-bipyridine) (bathophenanthroline disulfonate)[4-(2, 2′-bipyridin-4-yl)butanoic acid], used in the electrochemiluminescence (ECL) immunoassay. Combined with the uniquely well-established flow-through washing process in the automated ECL analyzers and the precise control over liquid handling, the assays performed with a 5-minute incubation period showed the same signal level and measurement precision as those of conventional ECL assays. Additionally, the absence of biotin and streptavidin components in the reagent formulation avoids the biotin-streptavidin interaction during assay incubation and fundamentally eliminates the interference of biotin, especially when used in some high-dose therapies. The results obtained from the procalcitonin prototype kit and the supporting evidence from other preliminary reagents (for SARS-CoV-2 N protein and troponin T) are general. The nonequilibrium detection, along with the downsized instrument design, makes the enhanced ECL (EECL) technology a fast high-performance POCT platform that provides the same high-quality data as those generated from the widely deployed [Ru(bpy)3]2+based laboratorial ECL systems.The anticipated regulatory approval and follow-up clinical implementation will beasignificant stride in the decade-long pursuit of novel ECL labels.

Integrated double flow-through purification of monoclonal antibodies using membrane adsorbers and single-pass tangential flow filtration

A flow-through process for monoclonal antibody (mAb) purification has been created by integrating two different membrane adsorbers (MAs) with single-pass tangential flow filtration (SPTFF) for continuous buffer exchange. First, a design of experiments (DoE) was carried out to investigate the influence of pH and conductivity on the removal of desoxyribonucleic acid (DNA) and host cell proteins (HCP), and to select buffer conditions for mAb flow-through mode operation for four different MAs. As next, breakthrough curve experiments were performed with the selected buffer conditions for each MA to analyze the binding behavior of mAb, DNA, and HCP. Then, the influence of the MA sequence in the double flow-through process on the mAb yield and DNA and HCP removal was studied in batch mode. The best sequence of MAs was used for the final integrated double flow-through polishing process, where the MAs were directly connected via SPTFF. The flow-through of the first (anion exchange) MA was continuously diafiltrated via SPTFF to buffer conditions for the second (cation exchange) MA. In this way, DNA (< 2 ppm) and HCP (< 29 ppm) were removed with simultaneously high mAb yield. Moreover, 36 times higher throughput was obtained than with a standard process that combines a packed-bed column with CEX resin in a bind and elute mode with an AEX MA in flow-through mode.