Cytotoxicity mechanism of non-viral carriers polyethylenimine and poly-l-lysine using real time high-content cellular assay

Cationic polymers polyethylenimine (PEI) and poly-l-lysine (PLL) used as non-viral gene/drug delivery vehicles, showed high cytotoxicity but their molecular mechanisms of toxicity have been inadequately understood. Therefore, we tried to investigate the toxicity pathway triggered by these polymers through a high-content cellular imaging technique. The results revealed that PEI induced apoptosis via an intrinsic pathway, whereas PLL showed cytotoxicity through both intrinsic and extrinsic caspase cascade. Both PEI and PLL provide different apoptotic activities on HepG2 cells depending on their molecular weight. The degree of apoptosis of PEI also depends on its structure. The branched PEI showed higher cytotoxicity than linear PEI. This observation was verified through Annexin V-FITC/PI assay and real-time high-content monitoring of cytosolic calcium, mitochondrial membrane disruption, and caspase-3 activation methods. The study therefore provides important implications on the molecular mechanisms of PEI and PLL induced cytotoxicity.     

Interfacial tension of polyethylene/polyethylene terephthalate with various compatibilizing agents

The effect of 12 different potential compatibilizing agents on the interfacial tension of polyethylene (PE) and polyethylene terephthalate (PET) is described. A wide range of compatibilizing agents based upon ethylene and a second comonomer were devised and used. They were divided into three categories. The first category (I) includes block polymers. The second category (II) includes random copolymers. The third category (III) includes reactive copolymers that should form graft copolymers during mixing with PET. The addition of various potential compatibilizing agents to the PE/PET binary system results in lowered interfacial tension. The efficiency of the different compatibilizing agents in reducing the interfacial tension is discussed. © 1996 John Wiley & Sons, Inc.     

Product design: Formulation of a screen-printable sintering-type conductive paste

Due to the complexity of the screen-printing operation and the rheological behaviors of the screen-printable paste, such a paste is usually formulated by trial-and-error. In this report, a systematic procedure, based on heuristics and mechanistic models, for the design of a screen-printable paste is developed. The procedure is demonstrated by a case study of the formulation of a conductive paste of copper particles.     

Analysis of Modified Nucleotide Aptamer Library Generated by Thermophilic DNA Polymerases

One of the pivotal steps in aptamer selection is the amplification of target-specific oligonucleotides by thermophilic DNA polymerases; it can be a challenging task if nucleic acids possessing modified nucleotides are to be amplified. Hence, the identification of compatible DNA polymerase and modified nucleotide pairs is necessary for effective selection of aptamers with unnatural nucleotides. We present an in-depth study of using 5-indolyl-AA-dUTP (TAdUTP) to generate oligonucleotide libraries for aptamer selection. We found that, among the eight studied DNA polymerases, only Vent(exo-) and KOD XL are capable of adapting TAdUTP, and that replacing dTTP did not have a significant effect on the productivity of KOD XL. We demonstrated that water-in-oil emulsion PCR is suitable for the generation of aptamer libraries of modified nucleotides. Finally, high-throughput sequence analysis showed that neither the error rate nor the PCR bias was significantly affected by using TAdUTP. In summary, we propose that KOD XL and TAdUTP could be effectively used for aptamer selection without distorting the sequence space of random oligonucleotide libraries.     

Cationic Effect of Ferrous Ions on Sulfide Capacity of CaO-FetO-Al2O3-SiO2 Slag System

Metallurgical and Materials Transactions B - The cationic effect of ferrous ions on the sulfide capacity of CaO-FetO-Al2O3-SiO2 slags was studied from the viewpoint of the ionic structure in the...     

A rapid method for the simultaneous determination of 25 anti-hypertensive compounds in dietary supplements using ultra-high-pressure liquid chromatography

A novel, stable, simple and specific ultra-performance liquid chromatography method with ultraviolet detection (205 nm) for the simultaneous analysis of 25 anti-hypertensive substances was developed. The method was validated according to the International Conference of Harmonisation guidelines with respect to linearity, accuracy, precision, limit of detection (LOD), limit of quantitation (LOQ) and stability. From the ultra-performance liquid chromatography results, we identified the LOD and LOQ of solid samples to be 0.20–1.00 and 0.60–3.00 μg ml^?1, respectively, while those of liquid samples were 0.30–1.20 and 0.90–3.60 μg ml^?1, respectively. The linearity exceeded 0.9999, and the intra- and inter-day precisions were 0.15–6.48% and 0.28–8.67%, respectively. The intra- and inter-day accuracies were 82.25–111.42% and 80.70–115.64%, respectively, and the stability was lower than 12.9% (relative standard deviation). This method was applied to the monitoring of 97 commercially available dietary supplements obtained in Korea, such as pills, soft capsules, hard capsules, liquids, powders and tablets. The proposed method is accurate, precise and of high quality, and can be used for the routine, reproducible analysis and control of 25 anti-hypertensive substances in various dietary supplements. The work presented herein may help to prevent incidents related to food adulteration and restrict the illegal food market.     

Two-step purification strategy for enhanced recovery of recombinant hepatitis B surface antigen from Pichia pastoris

Univariate screening on factors affecting the purification performance of recombinant hepatitis B surface antigen (HBsAg) on ion exchange chromatography (IEC) and size exclusion chromatography (SEC) and the establishment of a two-step purification strategy were performed. Amongst four IEC adsorbents examined, the use of Q Sepharose XL IEC adsorbent under optimized conditions together with optimized SEC purification was able to efficiently purify HBsAg. An established purification strategy comprising the two techniques further demonstrated adaptability for scale-up operations with a final total purification factor (PF) of 94.82 ± 16.20, HBsAg purity of 95.48% and recovery yield of 78.07%.     

A Boronic Acid Assay for the Detection of Mucin‐1 Glycoprotein from Cancer Cells

Cell surface glycoproteins are commonly aberrant in disease and act as biomarkers that facilitate diagnostics. Mucin‐1 (MUC1) is a prominent example, exhibiting truncated glycosylation in cancer. We present herein a boronic acid microplate assay for sensitive and high‐throughput detection of such glycoproteins. The immobilization of biotin–boronic acid 1 onto streptavidin plates generated a multivalent surface for glycoprotein recruitment and detection. We first validated the binding properties of 1 in solution through titrations with alizarin dye. Next, the microplate assay was explored through horseradish peroxidase (HRP) analysis as a proof‐of‐concept glycoprotein with chemiluminescence detection. Finally, this platform was applied for the detection of MUC1 directly from MCF‐7 human breast cancer cell lysates by using an HRP‐tagged antibody that targets the cancerous form of this glycoprotein. Sensitive, dose‐dependent detection of MUC1 was observed, showcasing the efficacy of this platform for detecting disease‐associated glycoproteins.