Durable modification of segmented polyurethane for elastic blood-contacting devices by graft-type 2-methacryloyloxyethyl phosphorylcholine copolymer

<div><p>We propose a novel application of 2-methacryloyloxyethyl phosphorylcholine (MPC) polymers for enhancing the performance of modified segmented polyurethane (SPU) surfaces for the development of a small-diameter vascular prosthesis. The SPU membranes were modified by random-type, block-type, and graft-type MPC polymers that were prepared using a double-solution casting procedure on stainless steel substrates. Among these MPC polymers, the graft-type poly(MPC-<i>graft</i>-2-ethylhexyl methacrylate [EHMA]), which is composed of a poly(MPC) segment as the main chain and poly(EHMA) segments as side chains, indicated a higher stability on the SPU membrane after being peeled off from the stainless steel substrate, as well as after immersion in an aqueous medium. This stability was caused by the intermiscibility in the domain of the poly(EHMA) segments and the soft segments of the SPU membrane. Each SPU/MPC polymer membrane exhibited a dramatic suppression of protein adsorption from human plasma and endothelium cell adhesion. Based on these results, the performance of SPU/poly(MPC-<i>graft</i>-EHMA) tubings 2 mm in diameter as vascular prostheses was investigated. Even after blood was passed through the tubings for 2 min, the graft-type MPC polymers effectively protected the blood-contacting surfaces from thrombus formation. In summary, SPU modified by graft-type MPC polymers has the potential for practical application in the form of a non-endothelium, small-diameter vascular prosthesis.</p></div

Micrographs of immunohistochemical staining of anti-human vimentin sections of nevus specimens 3, 6, and 12 months after implantation in the control and 200 MPa groups.

<p>Scale: 200 μm (high-magnification images in the lower right corner; scale: 50 μm). Anti-human vimentin sections from the control group show abundant remaining human cells stained with fast red. No human cells are noted in the 200 MPa group.</p

Photographs of the nevus specimens before implantation and 3, 6, and 12 months later in the control and 200 MPa groups.

<p>The nevus specimens in the control group 3 or more months after implantation show cysts and conversion to spherical forms. The color of nevus tissues in the 200 MPa group shows a gradual change to white.</p

Label-Free Separation of Induced Pluripotent Stem Cells with Anti-SSEA‑1 Antibody Immobilized Microfluidic Channel

When induced pluripotent stem cells (iPSCs) are routinely cultured, the obtained cells are a heterogeneous mixture, including feeder cells and partially differentiated cells. Therefore, a purification process is required to use them in a clinical stage. We described a label-free separation of iPSCs using a microfluidic channel. Antibodies against stage-specific embryonic antigen 1 (SSEA-1) was covalently immobilized on the channel coated with a phospholipid polymer. After injection of the heterogeneous cell suspension containing iPSCs, the velocity of cell movement under a liquid flow condition was measured. The mean velocity of the cell movement was 2.1 mm/sec in the unmodified channel, while that in the channel with the immobilized-antibody was 0.4 mm/sec. The eluted cells were fractionated by eluting time. As a result, the SSEA-1 positive iPSCs were mainly contained in later fractions, and the proportion of iPSCs was increased from 43% to 82% as a comparison with the initial cell suspension. These results indicated that iPSCs were selectively separated by the microfluidic channel. This channel is a promising device for label-free separation of iPSCs based on their pluripotent state

Microphotographs of sections of nevus tissue stained with hematoxylin and eosin before treatment and 3, 6, and 12 months after implantation in the control and 200 MPa groups.

<p>Scale: 200 μm (high-magnification images in the lower right corner; scale: 50 μm). In the control group, melanin pigments are seen at 12 months. In contrast, in the 200 MPa group, melanin granules at 6 months appear pale and small. Twelve months later, no large melanin granule is observed, except for few subtle granules.</p

The mean brightness values of nevus specimens in the control and 200 MPa groups.

<p>The brightness values at 6 and 12 months are significantly higher in the 200 MPa group than in the control group (*p<0.05, **p<0.01).</p

HE-stained sections of implanted pressurized skin without CE on Day 14.

<p>Black arrowheads indicate the epidermis of the implanted pressurized skin and red arrowheads indicate the dermis of the pressurized skin. Scale bar: 100 μm.</p

Comparison of the viability of pressurized skin.

<p>The mean absorbance of DMEM was set as an arbitrary zero point. The absorbance levels of NSS-0, DW-0, NSS-100, DW-100 and NSS-150 were significantly higher than that of DMEM (p<0.01). The absorbance levels of DW-150, NSS-200, DW-200, NSS-1000 and DW-1000 were significantly lower than those of NSS-0, DW-0, NSS-100, DW-100 and NSS-150 (p<0.01). The absorbance level of NSS-0 was significantly higher than those of NSS-100, DW-100 and NSS-150 (p<0.01). The absorbance level of NSS-150 was significantly lower than those of NSS-100 and DW-100 (p<0.01).</p

Micrographs of immunohistochemical staining of vWF.

<p>Red arrowheads indicate stained capillaries. Scale bar: 100 μm.</p

Our HHP procedure.

<p>Our HHP procedure.</p