Heparinized polyvinyl alcohol to specifically adsorb low-density lipoprotein from plasma

Photorenewable Azobenzene Polymer Brush-Modified Nanoadsorbent for Selective Adsorption of LDL in Serum

The elevated concentration of low-density lipoprotein (LDL) is recognized as a leading factor of hyperlipidemia (HLP), and selective adsorption of serum LDL is regarded as a practical therapy. Based on the superior structure-function characteristics of stimuli-responsive materials, a photorenewable nanoadsorbent (SiO₂@Azo@Gly) with high selectivity and reusability was developed using azobenzene as the functional ligand. Its principle was certified by the preparation of silicon nanoparticles with atom transfer radical polymerization (ATRP)-initiating groups via a sol-gel reaction and their subsequent grafting of azobenzene polymer brushes by surface-initiated ATRP, followed by modification with glycine. Immobilization of carboxylated azobenzene polymer brushes onto the nanoparticles endowed SiO₂@Azo@Gly with high adsorption selectivity and reusability. The advanced nanoadsorbent exhibited excellent LDL adsorption capacity at about 27 mg/g and could be regenerated by illumination with high efficiency (circulations ≥ 5); this was further verified by transmission electron microscopy (TEM) and Fourier-transform infrared (FTIR) analysis. SiO₂@Azo@Gly also demonstrated superior adsorption efficiency and selectivity in serum from HLP patients, the respective adsorption capacities of LDL, triglyceride, and total cholesterol were about 15.65, 24.48, and 28.36 mg/g, and the adsorption to high-density lipoprotein (cardioprotective effect) was only about 3.66 mg/g. Green regeneration of the nanoadsorbent could be achieved completely through a simple photoregeneration process, and the recovery rate was still 97.9% after five regeneration experiments.

Fe₃O₄@ZnO core-shell nanocomposites for efficient and repetitive removal of low density lipoprotein in plasma and on blood vessel

Low density lipoprotein (LDL)-apheresis therapy, which directly removes LDL from plasma by LDL-adsorbents in vitro is found to be clinically effective and safe to lower the LDL content in blood to prevent cardiovascular disease. Thus, developing excellent LDL adsorbents are becoming more and more attractive. Herein, functional Fe3O4@ZnO core-shell nanocomposites have been synthesized by a facile and eco-friendly two-step method. Not only do they possess high LDL adsorption (in PBS/plasma as well as on blood vessels) and favorable magnetic targeting ability but they can also be reused conveniently, which offer the Fe3O4@ZnO core-shell nanocomposites significant potential in the removal of LDL in vitro and in vivo.

Polydopamine-assisted deposition of heparin for selective adsorption of low-density lipoprotein

Low-density lipoprotein (LDL) is the main carrier of blood cholesterol, with elevated levels of LDL increasing the risk of atherosclerosis.

Impact of hydrophobic chain composition on amphiphilic macromolecule antiatherogenic bioactivity

Amphiphilic macromolecules (AMs) composed of sugar backbones modified with branched aliphatic chains and a poly(ethylene glycol) (PEG) tail can inhibit macrophage uptake of oxidized low-density lipoproteins (oxLDL), a major event underlying atherosclerosis development. Previous studies indicate that AM hydrophobic domains influence this bioactivity through interacting with macrophage scavenger receptors, which can contain basic and/or hydrophobic residues within their binding pockets. In this study, we compare two classes of AMs to investigate their ability to promote athero-protective potency via hydrogen-bonding or hydrophobic interactions with scavenger receptors. A series of ether-AMs, containing methoxy-terminated aliphatic arms capable of hydrogen-bonding, was synthesized. Compared to analogous AMs containing no ether moieties (alkyl-AMs), ether-AMs showed improved cytotoxicity profiles. Increasing AM hydrophobicity via incorporation of longer and/or alkyl-terminated hydrophobic chains yielded macromolecules with enhanced oxLDL uptake inhibition. These findings indicate that hydrophobic interactions and the length of AM aliphatic arms more significantly influence AM bioactivity than hydrogen-bonding.

Recyclable heparin and chitosan conjugated magnetic nanocomposites for selective removal of low-density lipoprotein from plasma

A new fabrication protocol is described to obtain heparin and chitosan conjugated magnetic nanocomposite as a blood purification material for removal of low-density lipoprotein (LDL) from blood plasma. The adsorbent could be easily separated with an external magnet for recyclable use since it had a magnetic core. The LDL level of plasma decreased by 67.3 % after hemoperfusion for 2 h. Moreover, the adsorbent could be recycled simply washing with NaCl solution. After eight cycles, the removal efficiency of the adsorbent was still above 50 %. The recyclable magnetic adsorbent had good blood compatibility due to the conjugation of heparin to the chitosan-coated magnetic nanocomposites. The fabricated magnetic adsorbent could be applied for LDL apheresis without side effects.