Analysis of filtration behavior using integrated column chromatography followed by virus filtration.

We evaluated filtration behavior and virus removal capability for a monoclonal antibodies (mAb) and plasma IgG under constant flow rate directly following flow-through column chromatography in an integrated process. mAb solution with quantified host cell protein (HCP) content processed in flow-through mode on in-series mixed-mode AEX and modified CEX columns connected to the Planova BioEX filter (pool-less) achieved HCP logarithmic reduction value (LRV) of 2.3 and 93.

Characterizing the impact of pressure on virus filtration processes and establishing design spaces to ensure effective parvovirus removal.

Virus filtration provides robust removal of potential viral contaminants and is a critical step during the manufacture of biotherapeutic products. However, recent studies have shown that small virus removal can be impacted by low operating pressure and depressurization. To better understand the impact of these conditions and to define robust virus filtration design spaces, we conducted multivariate analyses to evaluate parvovirus removal over wide ranges of operating pressure, solution pH, and conductivity for three mAb products on Planova™ BioEX and 20N filters.

Formation of apatite coatings on an artificial ligament using a plasma- and precursor-assisted biomimetic process.

A plasma- and precursor-assisted biomimetic process utilizing plasma and alternate dipping treatments was applied to a Leed-Keio artificial ligament to produce a thin coating of apatite in a supersaturated calcium phosphate solution. Following plasma surface modification, the specimen was alternately dipped in calcium and phosphate ion solutions three times (alternate dipping treatment) to create a precoating containing amorphous calcium phosphate (ACP) which is an apatite precursor. To grow an apatite layer on the ACP precoating, the ACP-precoated specimen was immersed for 24 h in a simulated body fluid with ion concentrations approximately equal to those in human blood plasma.

Vascular-inducing poly(glycolic acid)-collagen nanocomposite-fiber scaffold.

For regenerative medicine with scaffolds, the immediate cellularization of the scaffold accompanied by angiogenesis inside is an important event. Such the aim is generally pursued by combining basic fibroblast growth factor (b-FGF) or vascular endothelial growth factor (VEGF) with the scaffold. In this study, we produced the nanocomposite nanofiber composed of poly(glycolic acid), PGA, and collagen to accomplish the recruitment of host cells and peripheral blood vessels without the bio-derived matter like growth factors.

Evaluation of an anion-exchange hollow-fiber membrane adsorber containing γ-ray grafted glycidyl methacrylate chains.

It is widely recognized that membrane adsorbers are powerful tools for the purification of biopharmaceutical protein products and for this reason a novel hollow-fiber AEX type membrane adsorber has been developed. The membrane is characterized by grafted chains including DEA ligands affixed to the pore surfaces of the membrane. In order to estimate the membrane performance, (1) dynamic binding capacities for pure BSA and DNA over a range of solution conductivity and pH, (2) virus reduction by flow-through process, and (3) HCP and DNA removal from cell culture, are evaluated and compared with several other anion-exchange membranes.

Preparation of a bonelike apatite-polymer fiber composite using a simple biomimetic process.

A bonelike apatite-polymer fiber composite may be useful as an implant material to replace bone, the enthesis of a tendon, and the joint part of a ligament. We treated an ethylene-vinyl alcohol copolymer (EVOH) plate and knitted EVOH fibers with an oxygen plasma to produce oxygen-containing functional groups on their surfaces. The plasma-treated samples were alternately dipped in alcoholic calcium and phosphate ion solutions three times to deposit apatite precursors onto their surfaces.

Quantitative analysis of cell adhesion on aligned micro- and nanofibers.

In this study, we quantitatively analyzed the affinity of cell adhesion to aligned nanofibers composed of composites of poly(glycolic acid) (PGA) and collagen. Electrospun composite fibers were fabricated at various PGA/collagen weight mixing ratio (7, 18, 40, 67, and 86%) to generate fibers that ranged in diameter from 10 mum to 500 nm. Scanning electron microscopy (SEM) observation revealed that the PGA/collagen fibers were long and uniformly aligned, irrespective of the PGA/collagen weight mixing ratio.

Biomimetic coating of an apatite layer on poly(L-lactic acid); improvement of adhesive strength of the coating.

A biodegradable polymer coated with a bonelike apatite layer on its surface would be useful as a scaffold for bone tissue regeneration. In this study, poly(L-lactic acid) (PLLA) was treated with oxygen plasma to produce oxygen-containing functional groups on its surface. The plasma-treated specimen was then alternately dipped in aqueous CaCl(2) and K(2)HPO(4).

The formation of an antibacterial agent-apatite composite coating on a polymer surface using a metastable calcium phosphate solution.

A percutaneous device with antibacterial activity and good biocompatibility is desired for clinical applications. Three types of antibacterial agent: lactoferrin (LF), tetracycline (TC), and gatifloxacin (GFLX) were immobilized on the surface of an ethylene-vinyl alcohol copolymer (EVOH) using a liquid phase coating process. In this process, an EVOH plate was alternately dipped in calcium and phosphate ion solutions, and then immersed in a metastable calcium phosphate solution supplemented with 4, 40, or 400 microg/mL of the antibacterial agent.

Simple surface modification of poly(epsilon-caprolactone) to induce its apatite-forming ability.

A biodegradable polymer coated with a bone-like apatite layer on its surface is useful as a scaffold for bone tissue regeneration. In this work, a poly(epsilon-caprolactone) (PCL) surface was modified by an O2 plasma surface treatment to form oxygen-containing functional groups. The plasma-treated samples were subsequently dipped alternately in an alcoholic solution containing calcium ions and one containing phosphate ions to deposit apatite precursors on the surface.