Novel Thrombo-Resistant Coating Based on Iron−Polysaccharide Complex Multilayers

Abstract

The biocompatibility of iron-polysaccharide complexes has been well-documented. Herein, a stable thrombo-resistant coating was fabricated by consecutive adsorption of Fe (III) and polysaccharides including heparin (Hep) and dextran sulfate (DS) onto various surface by layer-by-layer self-assembly technique via both electrostatic interaction and chemical complexation process. The absorbance at 350 nm increased linearly with the number of Fe3+/Hep multilayer, indicating the formation of multilayer structure and the uniform coating. Compared with (Fe3+/Hep)10, the (Fe3+/DS/Fe3+/Hep)5 coating was more hydrophilic and stable due to the incorporation of DS. The activated partial thromboplastin time (APTT) and platelet adhesion assays showed that both (Fe3+/Hep)10 and (Fe3+/DS/Fe3+/Hep)5 coated surfaces were anticoagulant. The complexing with ferric ions did not compromise the catalytic capacity of heparin to promote antithrombin(III)-mediated thrombin inactivation. Chromogenic assays for heparin activity proved definitively that the inhibition of locally produced thrombin was contributed to the thromboresistance of the surface-bound heparin. The surface with Hep or DS as the outmost layer showed stronger anticoagulant activity than Fe3+, indicating that the outermost layer of the coating played a key role in anticoagulant activity. The utilization of dextran sulfate/heparin surfaces was more advantageous than merely the heparin surface for improving blood-contacting medical devices for long-term usage.

Heparin nanomodification improves biocompatibility and biomechanical stability of decellularized vascular scaffolds

“…22 In brief, acellular BJV scaffolds were cut into square sheets (1 cm × 1 cm, 10 samples each) and modified using four, seven, and ten cycles of heparin/DHI as described above. Each sheet was subjected to a tangential shaking wash in 40 mL of phosphate-buffered saline at 37°C, and 0.2 mL samples of the washed solution were removed after washing for one day and one, 2, 4, 6, and 8 weeks.…”

“…22 In brief, BJV scaffolds modified by seven cycles of heparin/DHI were cut into square sheets (1 cm × 1 cm), and every sheet was washed in 40 mL of phosphate-buffered saline at 37°C under 80 rpm shaking conditions. The sheets were removed after one day and one, 4, 6, and 8 weeks of washing (eight samples each), and then rinsed three times with phosphate-buffered saline for 3 minutes.…”

“…22,26 Briefly, platelet-rich plasma was generated by centrifugation for 15 minutes at 750 rpm. Scaffolds modified by seven cycles of heparin/ DHI were then cut into square sheets (1 cm × 1 cm, n = 6), and every sheet was positioned in contact with 1 mL of platelet-rich plasma for 3 hours in a humidified 5% CO 2 air atmosphere at 37°C.…”

“…Dai et al reported that complex multilayers of iron polysaccharide, which are used to modify a nitinol surface, provide a stable thromboresistant surface with good biocompatibility. 22 In the present study, our main objective was to develop a decellularized vascular scaffold with heparin nanomodification, and to improve the biocompatibility and biomechanical stability of acellular vascular scaffolds. Stable heparin-nanomodified scaffolds were created by alternating linkage of heparin and dihydroxy-iron (DHI) to the scaffolds via layer-by-layer self-assembly.…”

Surface modification of polysulfone based hemodialysis membranes with layer by layer self assembly of polyethyleneimine/alginate-heparin: a simple polyelectrolyte blend approach for heparin immobilization

“…The proposed strategy can be an economical alternative for the modification of hemodialysis membranes since HEP is an expensive compound compared to ALG. In previous studies, the LBL deposition of HEP with different polyelectrolytes such as chitosan, collagen, dextrin sulfate and albumin on different blood-contacting surfaces has been carried out [18,[25][26][27][28][29]. In these studies, HEP was used alone not only in the last layer of the assembly but also in each alternating layer to provide charge reversal of the polycation layer.…”