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For patients who are suffering from liver dysfunction or metabolic obstruction, excessive bilirubin (BIL) in their bodies may cause jaundice with irreversible cerebral injury. Traditional exchange transfusion and photodynamic therapy pose a risk of serious adverse reactions or limited curative effects. Therefore, as a generally used treatment, hemoperfusion (HP) purifies patients' blood with solid adsorbents. However, the development of clinical BIL absorbents is greatly impeded by low selectivity and unsatisfactory blood compatibility. Herein, inspired by oviparity, we propose BIL-imprinted poly(acrylic acid-co-sodium p-styrenesulfonate)-reduced graphene oxide (PAA-SS-rGO@BIL) hydrogel beads as BIL adsorbents via self-sacrificing micro-reactors. In the micro-reactors, cross-linked polymerization is achieved and a solidified gel is formed. The received hydrogel beads show outstanding selective adsorption capabilities toward BIL due to the recognition sites, and π-π and hydrophobic interactions. Such hydrogel beads possess superior blood compatibility owing to their bioinspired heparin-mimicking gel structure. Simulated BIL selective adsorption experiments in vitro demonstrate that the BIL concentrations in the plasma of a patient with severe jaundice can be restored to a moderate level within 3 hours. Therefore, hydrogel beads offer new options for clinical BIL adsorption.

Although a series of biomass-derived hemostats has been developed, the desire for green-prepared hemostatic materials with biosafety has not decreased. Herein, we constructed porous carboxymethyl chitosan/sodium alginate/Ca(OH)2 powders (PCSCPs) with suitable adaptability for instant control of irregular hemorrhage via a facile and green approach. By one-pot chemical crosslinking of carboxymethyl chitosan and sodium alginate, hydrogels were formed and immediately ionically cross-linked along with the generation of Ca(OH)2 to prepare PCSCPs. As hydrogel powders, PCSCPs with abundant hydrophilic carboxymethyl groups and porous hierarchically micro-nanostructures displayed a high water absorption ratio of over 1600%. The PCSCPs were confirmed with favorable hemocompatibility, non-cytotoxic effects and excellent degradability. Hemostasis assays in vitro showed that PCSCPs possessed an outstanding property of platelet activation and red blood cell aggregation. The PCSCPs effectively shortened the hemostatic time and blood loss to ca. 50% in rodent bleeding models compared with medical gauze and commercial chitosan-based hemostats. Furthermore, a mouse subcutaneous implantation model demonstrated an ignorable inflammation response and potential tissue repair capability of PCSCPs. It's believed that green-prepared and biomass-derived PCSCPs are feasible biomedical hemostatic materials in view of engineering and provide a promising platform to design hemostats in prehospital management and clinical settings.

Recently emerged hemoperfusion absorbents, e.g. ion-exchange resin, activated carbon, and other porous materials, provide numerous novel possibilities to cure chronic liver failure (CLF) and renal failure (CRF). However, the limited adsorption performance and unsatisfactory blood compatibility significantly impede the development of the absorbents. Hence, designing safe and self-anticoagulant hemoperfusion absorbents with robust toxin clearance remains a considerable challenge. Here, brand new Kevlar-based composite gel beads for hemoperfusion are prepared by interface assembly based on π-π interaction. First, Kevlar nanofiber-graphene oxide (K-GO) beads are produced by liquid-liquid phase separation. Then, sodium p-styrenesulfonate (SS) is adsorbed onto the K-GO interface by π-π interaction and initiated to achieve the composite gel (K-GO/PSS) beads with an interfacial crosslinked structure. Such composite gel beads possess superior mechanical strength and self-anticoagulation capability, owing to the dual-network structure and heparin-mimicking gel structure, respectively. Furthermore, the K-GO/PSS beads show robust adsorption capacities for different kinds of toxins due to their strong charge and π-π interactions. A simulated hemoperfusion experiment in vitro demonstrates that the concentrations of the toxins in the blood can be restored to normal values within 30 minutes. In general, we envision that such composite gel beads will provide new strategies for future clinical CLF and CRF treatments.

Rapid endothelialization and prevention of restenosis are two vital challenges for the preparation of a small-diameter vascular graft (SDVG), while postoperative infection after implantation is often neglected. In the present study, carboxymethyl chitosan (CMC) and chitosan (CS) were chosen as the anti-thrombotic and anti-bacterial components, respectively; and then an asymmetric vascular graft was fabricated by co-electrospinning of poly(ε-caprolactone) (PCL)/CMC and PCL/CS. The mechanical properties of the asymmetric vascular graft were much better than those of the native vessels. In vitro blood compatibility tests indicated that the inner layer of the graft could inhibit thrombosis effectively. The outer layer of the graft had a certain anti-bacterial effect owing to the addition of chitosan. Besides, the inner layer of the graft could greatly promote the growth of endothelial cells. It is believed that the asymmetric SDVG with anti-thrombotic and anti-bacterial functions could contribute to the future clinical implantation of tissue engineered vascular grafts.

Herein, a substrate-independent ultrathin hydrogel film was constructed on a microfiltration membrane through layer-by-layer (LbL) thiol-ene click chemistry to improve the antifouling and antibacterial properties. In our strategy, ene-functionalized dopamine was synthesized and coated onto a model substrate (polyethersulfone membrane) to introduce double bonds as anchoring sites for the hydrogel film; thiol-functionalized poly[oligo(ethylene glycol)mercaptosuccinate] (POEGMS) and ene-functionalized P(SBMA-co-AA) were synthesized as hydrogel precursors. The membrane was alternately immersed in the precursor solutions to form the ultrathin hydrogel film. Finally, Ag nanoparticles (AgNPs) were loaded into the hydrogel layer by adsorption and reduction procedures. By coating the hydrogel films, the loaded AgNPs could kill almost all the contacting bacteria and the bacteria in the surroundings, and the enhanced hydrophilicity of the modified membrane could effectively prevent the attachment of the bacteria. The membrane flux showed no significant decrease, the rejection ratio of BSA increased from 51% to 89%, and the FRR increased from 36% to 90%. Moreover, the improvement of the hemocompatibility was confirmed by the decline in the plasma protein adsorption, prolonged clotting times, low hemolysis ratio, and prevention of platelet adhesion. Compared with that of other techniques for attaching hydrogel films, the main advantage of the current technique is that the hydrogel film thickness could be well controlled within the nanometer range; thus, it could significantly improve the antifouling and antibacterial properties of the membrane, but without compromising its permeability. Another advantage is that it is versatile for various substrates such as PVDF, PAN, and CA. This study opens up a facile and versatile route for anchoring ultrathin hydrogel film onto polymeric membranes to achieve excellent antifouling, antibacterial and hemocompatible properties.