Accurate vector copy number determination in gammaretroviral vector producer cell clones using triplex digital droplet PCR.

Gammaretroviral vectors are widely used in cellular and gene therapy products because of the availability of stable vector producer cells. Accurately assessing vector copy number (VCN) is critical for selecting appropriate clones to avoid the risks of homologous recombination and complications in mutation detection. Traditional methods such as quantitative polymerase chain reaction (PCR) and Southern blotting have limitations in accuracy and throughput.

Analysis of nonhuman N-glycans as the minor constituents in recombinant monoclonal antibody pharmaceuticals.

Minor N-linked glycans containing N-glycolylneuraminic acid residues and/or α-Gal epitopes (i.e., galactose-α1,3-galactose residues) have been reported to be present in recombinant monoclonal antibody (mAb) therapeutics.

Charge heterogeneity of a therapeutic monoclonal antibody conjugated with a cytotoxic antitumor antibiotic, calicheamicin.

A robust and highly reproducible capillary isoelectric focusing (cIEF) method for the evaluation of charge heterogeneity of monoclonal antibody (mAb) pharmaceutical which contains covalently bound antitumor compounds was developed using a combination of commercially available dimethylpolysiloxane-coated capillary and carrier ampholyte. In order to optimize major analytical parameters for robust mobilization, experimental responses from three pI markers were selected. The optimized method gave excellent repeatability and intermediate precision in estimated pI values of charge variants with relative standard deviations (RSDs) of not more than 0.

Carbohydrate-protein interactions investigated on plastic chips statically coated with hydrophobically modified hydroxyethylcellulose.

We developed a novel method for rapid screening of carbohydrate-protein interactions using poly(methyl methacrylate) (PMMA) channels statically coated with hydrophobically modified hydroxyethylcellulose (HM-HEC). We found that a self-assembled monolayer (SAM) of HM-HEC on a PMMA surface intact by water allows rapid and reproducible separations of glycan samples using a 20 mM phosphate without HM-HEC. The underlying mechanism for dynamic and static coatings on the PMMA surface is discussed.

Accurate quantitation of salivary and pancreatic amylase activities in human plasma by microchip electrophoretic separation of the substrates and hydrolysates coupled with immunoinhibition.

A high-performance determination system for alpha-amylase isoenzyme activities in human plasma involving microchip electrophoresis with a plastic chip was developed. The combination of microchip electrophoresis for substrate and hydrolysate separation and an immunoinhibition method for the differentiation of isoenzyme activities using antihuman salivary amylase (S-AMY) mAb allowed the highly selective determination of amylase isoenzyme (S-AMY and pancreatic amylase (P-AMY)) activities even in a complex matrix such as a crude plasma sample. We used 8-aminopyrene-1,3,6-trisulfonic acid (APTS)-labeled maltohexaose (G6) as a substrate.

Determination of human blood glucose levels using microchip electrophoresis.

A high-performance monitoring system for human blood glucose levels was developed using microchip electrophoresis with a plastic chip. The combination of reductive amination as glucose labeling with fluorescent 2-aminoacridone (AMAC) and glucose-borate complex formation realized the highly selective detection of glucose even in a complex matrix such as a blood sample. The migration time of a single peak, observed on an electropherogram of AMAC-labeled plasma, closely resembled that of glucose standard solution.

Conformational separation of monosaccharides of glycoproteins labeled with 2-aminoacrydone using microchip electrophoresis.

The conformational separation of monosaccharides labeled with fluorescent 2-aminoacrydone (AMAC) was performed by electrophoresis on a plastic microchip with light-emitting diode confocal fluorescence detection. The AMAC-labeled five neutral monosaccharide mixture (D-glucose (Glc), D-mannose, D-galactose, L-fucose, and D-xylose) or two amino monosaccharide mixture (N-acetyl-D-glucosamine and N-acetyl-D-galactosamine) were well separated at pH 8.5 and 0.