Surfaces having dual fibrinolytic and protein resistant properties by immobilization of lysine on polyurethane through a PEG spacer

Abstract

The objective of this work is to develop a blood contacting surface that possesses both resistance to nonspecific protein adsorption and clot lysing properties. Chemical modification of a polyurethane (PU) surface with poly(ethylene glycol) (PEG); and lysine was used to create a plasminogen-binding potentially fibrinolytic surface. The preparation involves modification of the PU surface with dihydroxy PEG, reaction of the unreacted distal OH with N,N'-disuccinimidyl carbonate (DSC) to produce a PU-PEG-NHS surface, followed by conjugation of epsilon-amino-protected lysine (H-Lys(t-BOC)-OH) by reaction of the alpha-amino group with the NHS and deprotection. The result is a lysine-derivatized surface in which the epsilon-amino groups of the lysine are free to participate in binding plasminogen and tissue plasminogen activator (t-PA). Surfaces were characterized by X-ray photoelectron spectroscopy (XPS) and contact angle measurements. Protein adsorption experiments showed that nonspecific protein adsorption was greatly reduced on these surfaces and that they adsorbed significant quantities of plasminogen from plasma. After incubation with plasma and treatment with t-PA the surfaces were able to dissolve nascent plasma clots formed around them.

Corn trypsin inhibitor coating attenuates the prothrombotic properties of catheters in vitro and in vivo

“…Previous attempts at rendering blood-contacting surfaces nonthrombogenic have included approaches aimed at (a) reducing protein adsorption with agents such as PEG, polyethylene oxide, or albumin, (b) inhibiting platelet activation by coating surfaces with apyrase, (c) attenuating surface-induced clotting by coating with various anticoagulants, or (d) enhancing fibrinolysis by immobilizing lysine to promote the binding of plasminogen and/ or tissue plasminogen activator [32,[39][40][41]. In our studies, we used a combination of PEG and CTI, which were immobilized onto a base coated catheter surface.…”

Selective albumin-binding surfaces modified with a thrombin-inhibiting peptide

“…Thrombin adsorption on SAMs corresponds to less than 5% of the theoretical maximum for a thrombin monolayer, which was estimated to be between 271 and 301 ng cm À2 for molecules lying perpendicular or parallel to the surface [58]. This lower thrombin adsorption can be related to the non-fouling nature of the EG3 background, which can counteract the uptake of the protein of interest as described in other protein-surface systems [40,[59][60][61]. Immobilization of GGfPrt in higher concentrations did not increase thrombin adsorption since although GGfPrt-80-SAMs have six times more peptide than GGfPrt-20-SAMs, the amount of adsorbed thrombin was similar (13 ± 0.8 and 12 ± 1.1 ng cm À2 , respectively).…”

Mimicking the fibrinolytic system on material surfaces

“…4(a)). The as-prepared lysine-containing PDMS and PU surfaces were shown to reduce nonspecific protein adsorption significantly (but not entirely) while binding plasminogen from plasma with a high degree of selectivity [18,19]. The PEG-lysine modified PU surface, for example, reduced fibrinogen adsorption from buffer by ∼95% while increasing plasminogen adsorption from plasma by 90% compared with unmodified PU.…”

“…Such a surface would mimic the naturally occurring fibrinolytic process that occurs on the surface of fibrin [8]. This concept has been pursued in our laboratories over the past several years [9][10][11][12][13][14][15][16][17][18][19][20][21]. The present contribution is intended, in part, as an elaboration of this concept and an outline of developments to date.…”