The purification of large biotherapeutic modalities such as viral coat proteins, plasmid DNA, mRNA, therapeutic viruses and vesicles is more challenging than the purification of smaller and more established products such as monoclonal antibodies. This is because these entities, due to their large size, have limited access to binding sites present in the pores of conventional resin-based chromatographic media. However, this transport limitation could potentially be exploited for their purification using size exclusion chromatography (SEC).
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
October 2024
The soluble domain of the trimeric SARS-CoV-2 spike protein is a promising candidate for a COVID-19 vaccine. Purification of this protein from mammalian cell culture supernatant using conventional resin-based chromatography is challenging as its large size (∼550 kDa) restricts its access and mobility within the pores of the resin particles. This reduces binding capacity and process robustness very significantly as extremely low flow rates need to be used during purification.
View Article and Find Full Text PDFMembranes (Basel)
August 2024
A simple carrier phase based ultrafiltration technique that is akin to liquid chromatography and is suitable for medium-to-large volume sample preparation in the laboratory is discussed in this paper. A membrane module was integrated with a liquid chromatography system in a "plug and play" mode for ease of sample handling, and recovery of species retained by the membrane. The sample injector and pump were used for feed injection and for driving ultrafiltration, while the sensors and detectors were used for real-time monitoring of the separation process.
View Article and Find Full Text PDFIn this work, we compare two structurally near-amorphous rigid-rod polymers─poly(indacenodithiophene--benzothiadiazole), p(IDT-BT), and poly(indacenodithiophene--benzopyrollodione), p(IDT-BPD)─with orders of magnitude different mobilities to understand the effect charge carrier intrachain delocalization has on electronic transport. Quantum chemical calculations show that p(IDT-BPD) has a barrier to torsion that is significantly lower than that of p(IDT-BT) and is thus more likely to have reduced conjugation lengths. We utilize absorption and photoluminescence spectroscopy to characterize energetic disorder and show that p(IDT-BPD) has higher energetic disorder.
View Article and Find Full Text PDFArtificial nanozymes (enzyme-mimics), specifically metallic nanomaterials, have garnered significant attention recently due to their reduced preparation cost and enhanced stability in a wide range of environments. The present investigation highlights, for the first time, a straightforward green synthesis of biogenic platinum nanoparticles (PtNPs) from a natural resource, namely Prunella vulgaris (Pr). To demonstrate the effectiveness of the phytochemical extract as an effective reducing agent, the PtNPs were characterized by various techniques such as UV-vis spectroscopy, High-resolution Transmission electron microscopy (HR-TEM), zeta-potential analysis, Fourier-transform infrared spectroscopy (FTIR), and Energy dispersive spectroscopy (EDS).
View Article and Find Full Text PDFThis study provides the first experimental polarized intermolecular and intramolecular optical absorption components of field-induced polarons in regioregular poly(3-hexylthiophene-2,5-diyl), rr-P3HT, a polymer semiconductor. Highly aligned rr-P3HT thin films were prepared by a high temperature shear-alignment process that orients polymer backbones along the shearing direction. rr-P3HT in-plane molecular orientation was measured by electron diffraction, and out-of-plane orientation was measured through series of synchrotron X-ray scattering techniques.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
September 2023
As cases of multidrug resistant bacterial infections increase, scientists and clinicians around the world are increasingly turning to bacteriophages as alternatives to antibiotics. Even though our understanding of phage has increased significantly since the early days of its discovery, over a century ago, the currently used tools and technologies for phage purification for therapeutic applications are severely limited. Bacteriophages are produced by bacterial cultures, and impurities such as endotoxins must therefore be removed before clinical use.
View Article and Find Full Text PDFFlow uniformity within the device is critically important in membrane chromatography. Recent studies have shown that the design of the device has a significant impact on flow uniformity, and thereby on separation efficiency. The main premise of this work is that computational fluid dynamics (CFD) could serve as a fast and inexpensive tool for preliminary optimization of the design of a membrane chromatography device.
View Article and Find Full Text PDFBiosensors (Basel)
March 2023
Chronic pain is now included in the designation of chronic diseases, such as cancer, diabetes, and cardiovascular disease, which can impair quality of life and are major causes of death and disability worldwide. Pain can be treated using cannabinoids such as Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol (CBD) due to their wide range of therapeutic benefits, particularly as sedatives, analgesics, neuroprotective agents, or anti-cancer medicines. While little is known about the pharmacokinetics of these compounds, there is increasing interest in the scientific understanding of the benefits and clinical applications of cannabinoids.
View Article and Find Full Text PDFPEGylated proteins are usually purified using chromatographic methods, which are limited in terms of both speed and scalability. In this paper, we describe a microfiltration membrane-based hybrid method for purifying PEGylated proteins. Polyethylene glycol (or PEG) is a lower critical solution temperature polymer which undergoes phase transition in the presence of a lyotropic salt and forms micelle-like structures which are several microns in size.
View Article and Find Full Text PDFPhotoactive organic and hybrid organic-inorganic materials such as conjugated polymers, covalent organic frameworks (COFs), metal-organic frameworks (MOFs), and layered perovskites, display intriguing photophysical signatures upon interaction with light. Elucidating structure-photophysics-property relationships across a broad range of functional materials is nontrivial and requires our fundamental understanding of the intricate interplay among excitons (electron-hole pair), polarons (charges), bipolarons, phonons (vibrations), inter-layer stacking interactions, and different forms of structural and conformational defects. In parallel with electronic structure modeling and data-driven science that are actively pursued to successfully accelerate materials discovery, an accurate, computationally inexpensive, and physically-motivated theoretical model, which consistently makes quantitative connections with conceptually complicated experimental observations, is equally important.
View Article and Find Full Text PDFConventional hollow fiber hemodialyzers have a cylindrical shell-and-tube design. Due to their circular cross-section and radial flow distribution and collection in the headers, the flow of blood in the header as well as in the hollow fiber membranes is non-uniform. The creation of high shear stress and high shear rate zones or stagnation zones could result in problems, such as cell lysis and blood clotting.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
January 2023
Recombinant SARS-CoV-2 trimeric spike protein produced by mammalian cell culture is a potential candidate for a COVID-19 vaccine. However, this protein is much larger than most typical biopharmaceutical proteins and its large-scale manufacture is therefore challenging. Particularly, its purification using resin-based chromatography is difficult as the diffusive transport of this protein to and from its binding site within the pores of the stationary phase particles is slow.
View Article and Find Full Text PDFNon-polarizable empirical potentials have been proven to be incapable of capturing the mixing of methane-water mixtures at elevated pressures. Although density functional theory-based ab initio simulations may circumvent this discrepancy, they are limited in terms of the relevant time and length scales associated with mixing phenomena. Here, we show that the many-body MB-nrg potential, designed to reproduce methane-water interactions with coupled cluster accuracy, successfully captures this phenomenon up to 3 GPa and 500 K with varying methane concentrations.
View Article and Find Full Text PDFJ Chromatogr B Analyt Technol Biomed Life Sci
July 2022
The fractionation of positional isomers of a PEGylated protein is quite challenging as these have similar molecular weight, and only very slightly different surface charge. In this study, cation exchange z laterally-fed membrane chromatography (zLFMC), which has been shown to be suitable for high-speed, high-resolution protein purification, was used to fractionate positional isomers of mono-PEGylated lysozyme. The performance of the zLFMC device was compared with a commercial preparative cation exchange column having the same volume and ligand.
View Article and Find Full Text PDFThis paper discusses ultrahigh-speed, ultrahigh-resolution preparative protein separation using an in-house designed membrane chromatography device. The performance of the membrane chromatography device was systematically compared with an equivalent resin-packed preparative column. Experiments carried out using model proteins showed that membrane chromatography gave more than four times greater resolution than the preparative column, while at the same time being more than 19 times faster.
View Article and Find Full Text PDFWe describe and discuss a simple dry-compression technique for preparing a flat cuboid chromatography device containing a shallow packed-bed of crystalline hydroxyapatite nanoparticles. We then discuss the use of this device for fast protein separation in the bind-and-elute mode. Such separation could be carried out at quite low pressures, making it possible to use inexpensive low pressure chromatography systems.
View Article and Find Full Text PDFEngineered T cell therapies have revolutionized modern oncology, however processes for manufacturing T cell therapies vary and the impact of manufacturing processes On the cell product is poorly understood. Herein, we have used a commercially available hollow fiber membrane bioreactor (HFMBR) operated in a novel mode to demonstrate that T cells can be engineered with lentiviruses, grown to very high densities, and washed and harvested in a single, small volume bioreactor that is readily amenable to automation. Manufacturing within the HFMBR dramatically changed the programming of the T cells and yielded a product with greater therapeutic potency than T cells produced using the standard manual method.
View Article and Find Full Text PDFJ Phys Chem Lett
October 2021
We employ the Holstein model for polarons to investigate the relationship among defects, topology, Coulomb trapping, and polaron delocalization in covalent organic frameworks (COFs). We find that intrasheet topological connectivity and π-column density can override disorder-induced deep traps and significantly enhance polaron migration by several orders of magnitude in good agreement with recent experimental observations. The combination of percolation networks and micropores makes trigonal COFs ideally suited for charge transport followed by kagome/tetragonal and hexagonal structures.
View Article and Find Full Text PDFPEGylated proteins comprise a class of value-added biopharmaceuticals. High-resolution separation techniques are required for the purification of these molecules. In this study, we discuss the application of a newly developed z laterally-fed membrane chromatography (or zLFMC) device for carrying out high-resolution purification of a PEGylated protein drug.
View Article and Find Full Text PDFUnderstanding the underlying physical mechanisms that govern charge transport in two-dimensional (2D) covalent organic frameworks (COFs) will facilitate the development of novel COF-based devices for optoelectronic and thermoelectric applications. In this context, the low-energy mid-infrared absorption contains valuable information about the structure-property relationships and the extent of intra- and inter-framework "hole" polaron delocalization in doped and undoped polymeric materials. In this study, we provide a quantitative characterization of the intricate interplay between electronic defects, domain sizes, pore volumes, chemical dopants, and three dimensional anisotropic charge migration in 2D COFs.
View Article and Find Full Text PDFSimultaneously reducing the bed-height and increasing the area of cross-section, while keeping the bed-volume the same, would substantially reduce the pressure drop across a process chromatography column. This would minimize problems such as resin compaction and non-uniformity in column packing, which are commonly faced when using soft chromatographic media. However, the increase in macroscale convective dispersion due to the increase in column diameter, and the resultant loss in resolution would far outweigh any potential benefit.
View Article and Find Full Text PDFMany-body potential energy functions (PEFs) based on the TTM-nrg and MB-nrg theoretical/computational frameworks are developed from coupled cluster reference data for neat methane and mixed methane/water systems. It is shown that the MB-nrg PEFs achieve subchemical accuracy in the representation of individual many-body effects in small clusters and enables predictive simulations from the gas to the liquid phase. Analysis of structural properties calculated from molecular dynamics simulations of liquid methane and methane/water mixtures using both TTM-nrg and MB-nrg PEFs indicates that, while accounting for polarization effects, is important for a correct description of many-body interactions in the liquid phase, an accurate representation of short-range interactions, as provided by the MB-nrg PEFs, is necessary for a quantitative description of the local solvation structure in liquid mixtures.
View Article and Find Full Text PDFConspectusExcitons and polarons play a central role in the electronic and optical properties of organic semiconducting polymers and molecular aggregates and are of fundamental importance in understanding the operation of organic optoelectronic devices such as solar cells and light-emitting diodes. For many conjugated organic molecules and polymers, the creation of neutral electronic excitations or ionic radicals is associated with significant nuclear relaxation, the bulk of which occurs along the vinyl-stretching mode or the aromatic-quinoidal stretching mode when conjugated rings are present. Within a polymer chain or molecular aggregate, nuclear relaxation competes with energy- and charge-transfer, mediated by electronic interactions between the constituent units (repeat units for polymers and individual chromophores for a molecular aggregate); for neutral electronic excitations, such inter-unit interactions lead to extended excited states or excitons, while for positive (or negative) charges, interactions lead to delocalized hole (or electron) polarons.
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