Chromatographic Purification Research Articles

Potent antibacterial and cytotoxic bioactive compounds from endophytic fungi Diaporthe sp. associated with Salacia intermedia.

Antibacterial screening of endophytic fungi from Salacia intermedia identified Diaporthe longicolla as a potent strain exhibiting good activity against multidrug-resistant Staphylococcus aureus and Pseudomonas aeruginosa, with an MIC of 39.1µg/mL. Scale-up fermentation and chromatographic purification of this strain yielded three known compounds, which were cytochalasin J (1), cytochalasin H (2), and dicerandrol C (3), as identified by liquid chromatography - high mass resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance (NMR) spectroscopy. Among those compounds, dicerandrol C exhibited broad-spectrum antibacterial activity against ATCC and multidrug-resistant strains of Bacillus subtilis, S. aureus, and P. aeruginosa, and multidrug-resistant strains of Klebsiella pneumoniae and Escherichia coli, with MIC values ranging from 1.04 to 33.30 µM. Furthermore, dicerandrol C outperformed tetracycline in antibacterial efficacy against S. aureus ATCC 6538 and methicillin-resistant S. aureus (MRSA) strains (MIC of 1.04 µM). Further antibacterial evaluation showed that cytochalasin J (221.43 µM), cytochalasin H (202.59 µM), and dicerandrol C (tested at its MIC values of 1.04 µM for S. aureus ATCC 6538 and 16.65 µM for P. aeruginosa ATCC 15442) significantly inhibited bacterial biofilm formation. The biofilm inhibition percentages ranged from 61.09 to 78.17% for S. aureus and 41.22-56.83% for P. aeruginosa. In cytotoxicity assays against MCF-7 cells, all three compounds reduced cell viability (48.68-74.50%), with dicerandrol C demonstrating the highest potency. These findings highlight the potential of dicerandrol C as a powerful antibacterial and cytotoxic agent, facilitating further investigations into its therapeutic applications.

Sustainable synthesis of 1,2,3-triazoles using Cyrene as a biodegradable solvent in click chemistry.

The first successful synthesis of 1,2,3-triazoles using CyreneTM as a biodegradable and non-toxic solvent in click chemistry has been developed. In contrast to previous methods, this sustainable approach allows product isolation by simple precipitation in water, eliminating the need for organic solvent extractions and column chromatography purifications, thus minimizing waste consumption while reducing operational costs. The protocol, performed also at gram scale, has broad applicability and versatility, as shown with complex substrates like biologically active coumarins or triazole-linked bifunctional molecules. Finally, this protocol is also amenable to a three-component reaction involving organic halides, terminal acetylenes and sodium azide, thus avoiding the isolation of organic azides, difficult-to-handle species known for their environmental sensitivity.

Broad-spectrum affinity chromatography of SARS-CoV-2 and Omicron vaccines from ligand screening to purification.

Emerging variants of SARS-CoV-2 pose great technological and regulatory challenges to vaccine manufacturing, especially in downstream processing. To address this dilemma, the development of broad-spectrum affinity chromatography for the purification of wild-type SARS-CoV-2 and its variants is crucial. We propose a comprehensive strategy to achieve this goal via the identification of high-affinity peptides by affinity selection of phage display and next-generation sequencing (NGS) and the evaluation of chromatographic performance. Two peptides targeting the angiotensin-converting enzyme 2 (ACE2)-binding motif on the receptor-binding domain (RBD), HFVKTPARWAWG (SP-HFV) and HYRTSHWHHLLG (SP-HYR), were obtained from the most abundant sequences of the enriched phage library. They exhibited nanomolar affinity for the RBD and trimeric spike protein (Trimer S), and had broad-spectrum affinity for all the RBDs from the variants. Molecular dynamics simulations revealed the different binding regions of SP-HFV and SP-HYR in the ACE2-binding motif and key residues contributing to binding. After SP-HYR was coupled onto agarose matrices, chromatographic results showed that the RBD and Trimer S from the wild-type and Omicron variant could be adsorbed at pH 6.0-6.5 and eluted by increasing the salt concentration, exhibiting broad-spectrum and mild-elution characteristics of affinity chromatography. Finally, the affinity chromatography was applied for the purification of inactivated SARS-CoV-2 and Omicron vaccines, affording high yields (84.5-93.0 %) and purities (81.3-98.0 %), and great resistance to harsh cleaning-in-place in 20 cycles. This work clearly demonstrated the commercial potential of broad-spectrum affinity chromatography for vaccine purification to address the rapid variation of pathogenic viruses.

Stability indicating eco-friendly HPLC method development and validation for the estimation of bisoprolol fumarate and telmisartan

BackgroundTelmisartan and bisoprolol fumarate together are two medications that diminish arterial pressure. The current study comprises an evaluation of the proposed methodology's greenness regarding the HPLC method used to govern the medication mixture regardless of dose form A novel stability suggesting HPLC method's environmental effect was evaluated using the greenness metrics. Stress conditions comprising acidic, alkaline, oxidative, thermal, and photolytic degradation were applied for both of the medications.ResultsThe RP—HPLC method employing a reversed-phase C18 column with a gradient approach, the HPLC chromatography was carried out. The mobile phase consisted of acetonitrile, methanol, and phosphate buffer (60:35:5, %v/v/v), with the stationary phase being the Unisphere C18 column Agela Tech. The RP-HPLC method uses UV detection at 224 nm with chromatographic purification spanning linearities of 2.5–12.5 μg/mL for bisoprolol fumarate and 40.0–200.0 μg/mL for telmisartan, correspondingly. The procedure is accurate and precise, as demonstrated by an outcome that % RSD inside the permissible range. Additionally, various stressors were introduced to the medications. The approach's green credentials with respect to solvent utilization, chemical substances, expenditure of energy, and waste formation have been verified by the greenness data collected during the evaluation. No chromatographic or spectrum impediments caused by formulation additives have been observed.ConclusionBisoprolol fumarate and telmisartan could be measured simultaneously using the devised RP-HPLC method, which was simple, quick, sensitive, accurate, precise, linear, and stability indicating. The proposed approach showed ecological friendliness, robustness, sensitivity, and ease of use. As a result, the devised method could be applied to the regular quality checking of tablets and bulk medications.

Bioprocess development for microbial production and purification of cellobiose lipids by the smut fungus Ustilago maydis DSM 4500.

Cellobiose lipids (CBLs) are a class of glycolipid biosurfactants produced by various fungal strains. These compounds have gained significant interest due to their surface-active and antifungal properties, which are comparable to traditional synthetic surfactants and antimicrobials. Despite their potential applicability in various cosmetic, pharmaceutical, and agricultural formulations, significantly less research has been focused on their production and purification in comparison to other glycolipid biosurfactants, such as mannosylerythritol lipids (MELs) and sophorolipids. Hence, this work proposes the development of a bioprocess that involves the microbial production and high-level chromatographic purification of CBLs from a submerged culture of Ustilago maydis DSM 4500. After a highly purified CBL product was obtained, the factors affecting the production of this glycolipid were investigated. It was demonstrated that U. maydis DSM 4500 produces a specific structural variant of CBLs at a concentration of 1.36g/L on an optimized the growth medium. Also, it was established that when the C/N ratio was decreased, the CBL titer increased by 2.3-fold. Furthermore, supplementing the culture with ZnSO4 at a concentration of 0.04mg/L further increased CBL concentration to 4.95g/L, representing the highest CBL titer achieved in a single-stage bioprocess to date. This study developed a methodology for utilizing U. maydis as a high-level CBL producer, which could challenge other familiar CBL producers, such as Sporisorium scitamineum and Cryptococcus humicola.

Spiro thiochromene-oxindoles as novel anti-inflammatory agents: design, sustainable synthesis, in vitro and in silico evaluations.

A one-pot, acid-, base-, and metal-free, multicomponent strategy has been developed to synthesize spiro thiochromene-oxindole derivatives as potential anti-inflammatory agents. The synthesized compounds were screened in vitro for their anti-inflammatory activity by inhibiting heat-induced Bovine Serum Albumin (BSA) denaturation assay, revealing moderate to good efficacy. Compounds 4e, 4k, and 4h exhibited the highest activity, inhibiting BSA denaturation by 90.97-95.45% at 800 μg mL-1 concentration with half maximal inhibitory concentration (IC50) values of 127.477 ± 2.285, 190.738 ± 3.561, and 285.806 ± 8.894 μg mL-1, respectively. For mechanistic insights in silico studies were conducted, revealing binding affinities of the active compounds with cyclooxygenase-2 (COX-2) protein, with binding energies of -8.9 kcal mol-1 (4e), -8.7 kcal mol-1 (4k), and -8.6 kcal mol-1 (4h). Bioactivity and pharmacokinetic parameters were further analyzed, encompassing ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) characteristics. This study highlights the potential of spiro thiochromene-oxindoles as anti-inflammatory agents, warranting further exploration as potential leads. The synthetic strategy for these target compounds utilizes taurine as an eco-friendly bio-organic catalyst, facilitating an acid-, base-, and metal-free intramolecular C-S and C-C bond formation in aqueous media. The reaction involves a one-pot, three-component Knoevenagel-Thia-Michael cascade between substituted isatins, 1,3-dicarbonyls, and 2-naphthalene thiol. Key features of this green protocol include high yields, cost-efficiency, non-toxicity, atom economy, and acid-, base-, and metal-free synthesis in water. Additionally, the catalyst exhibits excellent reusability, maintaining its activity across three cycles with easy recovery, while product isolation is achieved through simple filtration, eliminating the need for chromatographic purification and organic solvents. These attributes underscore this approach's synthetic and environmental advantages, highlighting its potential for broader application in the development of anti-inflammatory agents.

Metal-free hydrodifunctionalization of enaminones for the synthesis of ketomethylene-functionalized phosphoryl alcohols.

Reported here is a set of three-component reactions of enaminones with diaryl phosphine oxides and water for the synthesis of ketomethylene-functionalized gem-phosphoryl alcohols via enaminone hydrodifunctionalization, enabling the cascade construction of new C-P, C-O and C-H bonds. The method displays notable advantages including mild metal-free conditions, a broad application scope and being free of the need to carry out chromatographic purification.

Chromatography Media and Purification Processes for Complex and Super-large Biomolecules: A Review

Chromatography Media and Purification Processes for Complex and Super-large Biomolecules: A Review

Determination of 12 halogenated organic pollutants in edible fish by ultra performance liquid chromatography-high resolution mass spectrometry combined with ultrasound-assisted extraction and gel permeation chromatography purification

Halogenated organic pollutants (HOPs) have attracted considerable attention owing to their persistence, bioaccumulation, and toxicity. The development of methods to detect HOPs in fish is challenging owing to the compositional complexity of fish matrices, which contain high levels of lipids and relatively low concentrations of HOPs. In addition, the lipophilicity of most HOPs renders their extraction difficult. Moreover, the simultaneous determination of multiple HOPs to achieve the high-throughput screening of these analytes is complex. In this study, a reliable and efficient pretreatment method based on ultrasound-assisted extraction, gel permeation chromatography purification, and ultra performance liquid chromatography-high resolution mass spectrometry (UPLC-HRMS) was developed for the determination of 12 HOPs in edible fish. The procedures of sample extraction and purification and LC-HRMS detection parameters were optimized to improve the performance of the method. Fresh fish samples were thoroughly rinsed with water, and non-edible parts, including the skin, bones, and phosphorus, were removed. The fish were weighed, cut into small pieces, and vacuum freeze-dried for 48 h. Subsequently, a freeze grinder was used to grind the dried fish into a fine powder. Exactly 2 g of the fish powder was weighed, fortified with isotope-labeled internal standards of the HOPs, and allowed to stand for 5 min. Methanol-acetonitrile (1∶1, v/v) was then added, followed by vortex mixing and ultrasonication. After centrifugation, the supernatant was transferred to a fresh tube. The extraction process was repeated twice and all extracts were combined. The extract was evaporated under a gentle nitrogen flow and redissolved in a mixture of ethyl acetate-cyclohexane (1∶1, v/v). The sample mixture was cleaned using gel permeation chromatography, and the eluate was collected and concentrated under a nitrogen flow. Sample residuals were reconstituted with water-methanol (1∶1, v/v) prior to instrumental analysis. Chromatographic separation was performed using an ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm). Water containing 2 mmol/L NH4Ac and acetonitrile were used as the mobile phases, and an optimized gradient elution program was applied. Isotope dilution and an internal standard method were used to quantify the HOPs. An electrospray ionization source operated in negative mode was applied to ionize the HOPs, and a full scan together with data-dependent acquisition (DDA) was applied for HRMS. Excellent linearities (R2>0.99) were obtained for all HOPs in the quantification range of 1.0-1000.0 ng/mL. The limits of quantification were 0.5 ng/g. The analytical method was validated using pooled fish samples fortified with HOP standards (4, 40, and 400 ng/g). The recoveries of the HOPs were in the range of 67.6%-133.8%, and the corresponding RSDs were 0.5%-15.6%. A total of 27 commercially available fish samples were analyzed using the developed method, and the results revealed the presence of HOPs in the fish, indicating the practicability of the method for real-world samples. The developed method is rapid, accurate, precise, and suitable for detecting HOPs in fish. This study provides a useful approach for environmental monitoring and food safety assurance by enabling the accurate and efficient analysis of HOPs in commonly consumed fish. Given increasing global concerns over HOPs, the method developed in this study will provide practical technical support for consumers aiming to reduce their exposure to and the adverse impacts of HOPs via fish.

Towards a Platform Chromatography Purification Process for Adeno-Associated Virus (AAV).

Adeno-associated virus (AAV) is a versatile viral vector technology that can be engineered for specific functionality in vaccine and gene therapy applications. One of the major challenges in AAV production is the need for a GMP-ready platform-based approach to downstream processing, as this would lead to a standardized method for multiple products. Chromatography has huge potential in AAV purification, as it is a scalable method that would enable manufacturing to a high degree of purity, potency, and consistency. Multiple factors need to be considered when developing a chromatography platform, including the chromatography type, format, and mode of operation, along with other commercial considerations that have not been comprehensively reviewed until now. In addition to chromatography factors, this review will also consider the current understanding of AAV characteristics: this will include net surface charge, structural properties, and size, as well as their interactions with metal ions or receptors, and how this impacts the development of a chromatography platform.

Non-affinity platform for processing knob-into-hole bispecific antibody

Bispecific antibodies hold significant potential as next-generation biotherapeutics owing to their ability to simultaneously bind to two targets. However, the development of bispecific antibodies as biotherapeutics has been hindered by the high levels of byproducts produced, including both high molecular weight and low molecular weight variants. In addition, the inevitable expression of homodimers in host cells presents further obstacles to the commercial development of bispecific antibodies as therapeutics. These byproducts, which share similar physicochemical properties with the target, pose several challenges for downstream purification processes. In this study, we present a non-protein A purification platform that employ a one-step polishing chromatography to purify bispecific antibodies. Mixed-mode Capto adhere resin was used to capture the target protein at pH 7.90 ± 0.10, followed by anion exchange chromatography as a polishing step. Overall, the results of this two-step chromatography purification method demonstrated at final product purity of 98% as assessed by size-exclusion high-performance liquid chromatography (SEC-HPLC) and 98% by reversed-phase-high-performance liquid chromatography (RP-HPLC), with residual host cell proteins controlled at 10 ppm and an excellent recovery rate of approximately 60%. This study presents a non-protein A capture platform, offering a simplified, streamlined, and competitive alternative to conventional affinity chromatography.Graphical

A New Synthesis of Enantiopure Amine Fragment: An Important Intermediate to the Anti-HIV Drug Lenacapavir.

Herein, we describe a new seven-step approach to prepare (S)-1-(3,6-dibromopyridin-2-yl)-2-(3,5-difluorophenyl)ethan-1-amine ((S)-4) from the inexpensive 2-(3,5-difluorophenyl)acetic acid. The key steps in the sequence include (1) the Weinreb amide-based ketone synthesis to provide an entry point to the core structure; (2) simple functional group transformations to afford the racemic amine 4-rac; and (3) dynamic kinetic resolution (DKR) to access the chiral amine (S)-4. This seven-step process delivered the enantiopure amine (S)-4 in an overall isolated yield of approximately 15%. The process was demonstrated on a decagram scale, and the process requires no chromatographic purifications. Single-crystal X-ray crystallography measurements verified the chiral amine structure and absolute configuration.

Silver Oxide Promoted Synthesis of Alpha O-GalNAc Containing Glyco-Amino Acids: Synthesis of Core 2 Containing Glyco-Amino Acids for Solid Phase Synthesis of Glycopeptides.

O-GalNAc glycans on glycoproteins with eight different core structures sharing a common α-glycosidic linkage (O-GalNAc-α-Ser/Thr) are critical in various physiological and pathological processes. Among the eight O-GalNAc glycan cores, core 2 characterized by a GlcNAcβ1-6(Galβ1-3)GalNAc structural motif plays a significant role in regulating diverse biological processes, such as immune response modulation, adhesive properties of selectins, and gastrointestinal tract protection. However, the large-quantity synthesis of core 2 containing glyco-amino acids for downstream solid-phase peptide synthesis is challenging. In this work, we successfully employed a silver oxide for coupling a 2-azido-galactosyl chloride donor with two acceptors, Fmoc-Ser/Thr-OtBu, respectively, for the large-scale synthesis of the two important intermediates, α-GalN3-Fmoc-Ser/Thr-OtBu, which can be further utilized for the large-scale synthesis of core 2 containing glyco-amino acids. The two intermediates, α-GalN3-Fmoc-Ser/Thr-OtBu, were utilized for synthesizing core 2 containing Fmoc-Ser/Thr-COOH. The synthesis of core 2 containing Fmoc-Ser-COOH was achieved on a 1.95 g scale, while the synthesis of core 2 containing Fmoc-Thr-COOH was achieved on a 0.38 g scale. Additionally, the synthesis of the 2-azido-galactosyl chloride donor was optimized into a three-step process with only one column chromatography purification. Finally, core 2 containing Fmoc-Ser/Thr-COOH were applied for the synthesis of glycosylated CCR1 and CCR5 N-terminal peptides.

Structural characterization of polysaccharide isolated from Inonotus hispidus and its anti-obesity effect based on regulation of the interleukin-17-mediated inflammatory response.

A heteropolysaccharide (IHP3) with a molecular weight of 22.0 kDa was isolated from Inonotus hispidus (Bull.: Fr.) P. Karst using column chromatography purification from water extraction. Its backbone was predominantly composed of →6)-α-D-Galp-(1→, →2,6)-α-D-Galp-(1→,→6)-α-D-O-Me-Galp-(1→, →3)-α-D-Manp-(1→, and →3,4,6) -β-D-Galp-(1 → residues, branched at C2 of partial α-D-Galp, or C3 and C4 of β-D-Galp, and terminated by α-D-Manp, and α-L-Fucp. In high-fat diet (HFD)-fed obese mice, IHP3 effectively suppressed body weight and plasma glucose gain, decreased fat accumulation, ameliorated lipid metabolism, and protected liver function from HFD-induced damage. Combining the analysis of gut microbiota metabolomics, hepatic proteomics and biochemical detection revealed, IHP3 significantly altered cecum fecal metabolite abundances, inhibited the phosphorylation of peroxisome proliferator-activated receptor gamma, and promoted the browning of white adipose tissue and the activation of brown adipose tissue. These changes collectively contributed to alleviating obesity symptoms by suppressing the interleukin (IL)-17-mediated inflammatory response in obese mice. Therefore, these findings suggest that IHP3 could be a potential candidate for the development of anti-obesity drugs.

Human Biodistribution and Radiation Dosimetry of the Targeting Fibroblast Growth Factor Receptor 1-Positive Tumors Tracer [68Ga]Ga-DOTA-FGFR1-Peptide.

Objective: [68Ga]Ga-DOTA-FGFR1-peptide is a novel positron emission tomography (PET) radiotracer targeting fibroblast growth factor receptor 1 (FGFR1). This study evaluated the safety, biodistribution, radiation dosimetry, and imaging potential of [68Ga]Ga-DOTA-FGFR1-peptide. Methods: The FGFR1-targeting peptide DOTA-(PEG2)-KAEWKSLGEEAWHSK was synthesized by manual solid-phase peptide synthesis with high-performance liquid chromatography purification, and labeled with 68Ga with DOTA as chelating agent. We recruited 14 participants and calculated the radiation dose of 4 of these pathologically confirmed nontumor subjects using OLINDA/EXM 2.2.0 software. At the same time, the imaging potential in 10 of these lung cancer patients was evaluated. Results: The biodistribution of [68Ga]Ga-DOTA-FGFR1-peptide in 4 subjects showed the highest uptake in the bladder and kidney. Dosimetry analysis indicated that the bladder wall received the highest effective dose (3.73E-02 mSv/MBq), followed by the lungs (2.36E-03 mSv/MBq) and red bone marrow (2.09E-03 mSv/MBq). No normal organs were found to have excess specific absorbed doses. The average systemic effective dose was 4.97E-02 mSv/MBq. The primary and metastatic tumor lesions were clearly visible on PET/computed tomography (CT) images in 10 patients. Conclusion: Our results indicate that [68Ga]Ga-DOTA-FGFR1-peptide has a good dosimetry profile and can be used safely in humans, and it has significant potential value for clinical PET/CT imaging.

IgG-Binding Peptidomimetic Mixed-Charge Polymer-Modified Resins for Chromatographic Purification of Antibodies.

The process of antibody purification using Fc affinity ligands such as protein A, G, and L faces several challenges including high cost, low stability, and loss of antibody activity due to harsh elution conditions. Here, we describe a chromatographic purification of antibodies utilizing a pH-responsive mixed-charge polymer that mimics the IgG-binding peptide (Z34C) derived from the B domain of protein A. The protein A mimetic resins were prepared by modifying the surface of a TOYOPEARL, methacrylate resin with a polymer that mimics the amino acid sequence of Z34C and the functions of histidine and acidic and neutral amino acids using histamine methacrylamide (HisMA), methacrylic acid, and neutral monomers. The therapeutic monoclonal antibody (mAb), rituximab, was retained on the column at pH 7 and eluted under mildly acidic conditions at pH 5 using a protein A mimetic resin (HisMA20-EEMA) optimized for antibody interaction. The injected antibodies were selectively captured on the column by hydrophobic and electrostatic interactions with the protein A mimetic polymer under neutral conditions and eluted by electrostatic repulsion under acidic conditions. The HisMA20-EEMA column successfully purified mAbs from mixtures with BSA, mouse ascites fluid, and hybridoma cell culture supernatant. In addition, the HisMA20-EEMA column consistently achieved 90% antibody recovery in 100 consecutive purifications from cell culture supernatant. The antibody purification method presented in this study is low cost, highly durable, easy to synthesize, and allows for mild elution conditions. The results demonstrate that the approach of mimicking IgG-binding peptides with mixed-charge polymers is useful for the development of column packing materials for antibody purification.

Development of a Novel Prosthetic Click-Linker for Radioiodination of Antibody-Based Radiopharmaceuticals with High Stability and Specificity.

Radioiodine has been exploited in nuclear medicine for diagnostic and therapeutic purposes in various diseases. There are two radioiodination methods for biomolecules, that is, (1) direct radioiodination of tyrosine or histidine residue in a biomolecule and (2) indirect radioiodination by using a prosthetic group, which bridges radioiodine and the biomolecule. While directly radioiodinated biomolecules suffer from deiodination in vivo, the most commonly used indirect labeling method based on N-succinimidyl-3-[*I]iodobenzoate has a problem of inconvenience due to an high-performance liquid chromatography (HPLC) purification process. To tackle both issues, a novel prosthetic click-linker-antibody conjugate (3-[123/125I]iodobenzoyl-PEG4-tetrazine-TCO-PEG4-trastuzumab (3-[123/125I]IBTTT)) with favorable radiochemical yield (>57%) and purity (>99%) was developed using a fluorous tin-based organotin precursor with streamlined purification process utilizing fluorous solid-phase extraction (FSPE) cartridge and spin column. In vitro binding studies demonstrated that 3-[125I]IBTTT maintained its biological activity with a KD value (5.606 nM) comparable to that of unmodified trastuzumab (5.0 nM). In vivo imaging of 3-[123I]IBTTT in a human epidermal growth factor receptor 2 (HER2)-expressing gastric cancer mouse model revealed favorable tumor accumulation and negligible thyroid uptake compared to directly radioiodinated trastuzumab ([123I]trastuzumab). It was also confirmed, by blocking experiments and a biodistribution study, that the tumor accumulation of 3-[123I]IBTTT was attributed to HER2-specific binding. In summary, we developed a novel radioiodinated prosthetic click-linker agent (3-[123/125I]IBTTT) with favorable radiochemical yield, purity, stability, and in vivo behavior, providing a highly promising tool for targeted imaging and potential therapy of HER2-positive cancers.

Simple and easy functionalization of para-hydroxy POCOP-M (M = Ni(II), Pd(II)) pincer complexes: synthesis of multimetallic species.

A facile and efficient method for synthesizing mono- and bi-metallic pincer complexes (3-Ni/Ni and 3-Ni/Pd) has been developed. The procedure involves a 1 : 1 stoichiometric reaction of a para-hydroxy POCOP pincer complex with cyanuric chloride in the presence of [NaB(OMe)4], which selectively affords the mono-substituted pincer complexes (2-Ni and 2-Pd). These complexes are then further reacted with another equivalent of the para-hydroxy POCOP pincer complex to produce the desired multimetallic species (3-Ni/Ni and 3-Ni/Pd). The complexes can be easily isolated in moderate to good yields using chromatographic column purification. This straightforward synthesis procedure offers an attractive option for the preparation of multimetallic complexes. Furthermore, the molecular structures of complexes 2-Ni, 2-Pd, 3-Ni/Pd and 3-Ni/S were determined. The crystal packing of the structures was stabilized by various interactions including C-H⋯X (X = N, Cl, and F), π⋯π, and C-F⋯F interactions, contributing to their unique topologies. While 2-Ni and 2-Pd complexes exhibit similar molecular structures, they display distinct arrangements in their crystalline packing, such as monomeric chains in 1D arrangement along the c-axis for 2-Ni, and a symmetric dimeric species creating a 2D arrangement in the direction of the bc-axes for 2-Pd. The latter was corroborated by Hirshfeld surface analysis and 2D dimensional fingerprint plots of each crystal structure.

Purification of plasmid DNA using a novel two stage chromatography process

The chromatography process of large-scale plasmid purification with high efficiency and low cost has always been a major challenge. We established a two-step plasmid chromatography purification process combining multimodal and thiophilic chromatography with an overall chromatography yield of nearly 70%. Capto Core 700, a multimodal core–shell particle, was firstly used to remove the impurities from the crude lysate. The effects of different experimental conditions on chromatography recovery and impurity removal were screened. Compared to conventional size exclusion chromatography, the sample load and flow rate of this step were enhanced by 40-fold and 5-fold, respectively, while maintaining a 90% yield. For the thiophilic chromatography (Capto PlasmidSelect), the method of Design of Experiments (DoEs) was used to study the influence of parameters on the results. The effects of ammonium sulfate concentration, sodium chloride concentration and flowrate in the elution phase were studied and optimized with a central composite design model consisting of 17 experiments. The versatility of this process was demonstrated by successfully purifying three different lentiviral packaging plasmids (pLP1, pLP2 and pLP/VSVG) and the target plasmid containing green fluorescent protein (GFP). Purified plasmids consistently achieved a supercoiled purity of at least 90% with endotoxin levels below 5 EU/mg. Lentiviral vectors packaged using these plasmids exhibited high infectious titers of 1 × 107 TU/mL, thereby verifying the process applicability for diverse plasmid purification requirements.

A Gram Scale Synthesis of 3,4-Dihalogen Substituted 1,8-Naphthalimides

A general protocol for the synthesis of 3,4-dihalogen substituted 1,8-naphthalimides is proposed, starting from available and cheap 1,8-naphthalic anhydride. The reported new compounds have only bromine or chlorine atoms as substituents, in contrast to the known iodo-containing analogues. This is an advantage in possible aryl nucleophilic substitution or cross-coupling modifications, making them interesting and important building-block molecules in naphthalimide chemistry. Although the procedure includes five synthetic steps, they are quick and straightforward. The overall yields are relatively high (48–62%), and only one column of chromatographic purification is needed. All the reactions were carried out on a multigram scale to allow the target building-block compounds to be obtained in sufficient amounts for further derivatizations.