Enhanced Hemocompatibility of a Direct Chemical Vapor Deposition-Derived Graphene Film

Lipid-assisted PEG-b-PLA nanoparticles with ultrahigh SN38 loading capability for efficient cancer therapy

The topoisomerase I inhibitor, 7-ethyl-10-hydroxycamptothecin (SN38), has demonstrated potent anticancer activity. However, its clinical application is hindered by its low solubility and high crystallization propensity, which further complicates its encapsulation into nanoparticles for systemic delivery. Herein, we explore the utilization of lipid-assisted poly(ethylene glycol)-block-poly(D,L-lactide) (PEG-b-PLA) nanoparticles to achieve ultrahigh loading capability for SN38. Through the introduction of cationic, anionic, or neutral lipids, the SN38 loading efficiency and loading capacity is elevated to >90% and >10% respectively. These lipids efficiently attenuate the intermolecular π-π stacking of SN38, thereby disrupting its crystalline structure. Moreover, we assess the therapeutic activity of SN38-loaded formulations in various tumor models and identify an anionic lipid 1,2-dioleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) sodium salt (DOPG)-assisted formulation that exhibits the highest anticancer activity and has favorable biosafety. Overall, our findings present a simple and robust strategy to achieve ultrahigh loading efficiency of SN38 using commonly employed PEG-b-PLA nanoparticles, opening up a new avenue for the systemic delivery of SN38.

3D-Structured and Blood-Contact-Safe Graphene Materials

Graphene is a promising material that may be potentially used in biomedical applications, mainly for drug delivery applications. In our study, we propose an inexpensive 3D graphene preparation method by wet chemical exfoliation. The morphology of the graphene was studied by SEM and HRTEM. Moreover, the volumetric elemental composition (C, N, and H) of the materials was analyzed, and Raman spectra of prepared graphene samples were obtained. X-ray photoelectron spectroscopy, relevant isotherms, and specific surface area were measured. Survey spectra and micropore volume calculations were made. In addition, the antioxidant activity and hemolysis rate in contact with blood were determined. Activity against free radicals of graphene samples before and after thermal modification was tested using the DPPH method. The RSA of the material increased after graphene modification, which suggests that antioxidant properties were improved. All tested graphene samples caused hemolysis in the range of 0.28-0.64%. The results showed that all tested 3D graphene samples might be classified as nonhemolytic.

Anticoagulation polyvinyl chloride extracorporeal circulation catheters for heparin-free treatment

Extracorporeal circulation (ECC) catheters have potential to be blood compatible and could be used to prevent thrombotic occlusion. Here, we produced heparin-mimicking anticoagulation PVC tubing on a large scale by synthesizing a heparin-mimicking polymer (HMP) and co-extruding. The PVC@HMP catheter was evaluated using whole human blood in vitro, which indicated it could prevent plasma protein attachment, reduce platelet adhesion and activation, and inhibit coagulation factors (XII, XI, IX, and VIII). Moreover, the anticoagulation PVC tubing was assembled into extracorporeal circulation with a New Zealand rabbit model, manifesting excellent real-time antithrombogenic properties without systemic heparin anticoagulation in vivo. The rapid recovery of coagulation factors after operation further confirmed its superiority over heparin, which would not completely inactivate the activity of those coagulation factors (XII, XI, IX and VIII). In addition, the PVC@HMP-1 catheters remain patent after being implanted in rats for 28 days without apparent inflammation and mortality complications. The anticoagulation PVC tubes could be used to construct various systemic and integrative anticlotting biomedical devices, which would dramatically reduce the introduction of heparin into blood circulation, thus preventing side effects and promoting the development of heparin-free treatment.

Preparation, properties and application of graphene-based materials in tissue engineering scaffolds

Tissue engineering has great application prospect as an effective treatment for tissue and organ injury, functional reduction or loss. Bioactive tissues are reconstructed and damaged organs are repaired by the three elements including cells, scaffold materials and growth factors. Graphene-based composites can be used as reinforcing auxiliary materials for tissue scaffold preparation because of their large specific surface area, and good mechanical support. Tissue engineering scaffolds with graphene-based composites have been widely studied. Part of research have focused on the application of graphene-based composites in single tissue engineering; The basic principles of graphene materials used in tissue engineering are summarized in some researches. Some studies emphasized the key problems and solutions urgently needed to be solved in the development of tissue engineering, and discussed their application prospect. Some related studies mainly focused on the conductivity of graphene, and discussed the application of electroactive scaffolds in tissue engineering. In this review, the composite materials for preparing tissue engineering scaffolds are briefly described, which emphasizes the preparation methods, biological properties and practical applications of graphene-based composite scaffolds. The synthetic techniques with stressing solvent casting, electrospinning and 3D printing are introduced in detail. The mechanical, cell-oriented and biocompatible properties of graphene-based composite scaffolds in tissue engineering are analyzed and summarized. Their applications in bone tissue engineering, nerve tissue engineering, cardiovascular tissue engineering and other tissue engineering are summarized systematically. In addition, this work also looks forward to the difficulties and challenges in the future research, providing some references for the follow-up research of graphene-based composites in tissue engineering scaffolds.

Predicting the In Vivo Performance of Cardiovascular Biomaterials: Current Approaches In Vitro Evaluation of Blood-Biomaterial Interactions

The therapeutic efficacy of a cardiovascular device after implantation is highly dependent on the host-initiated complement and coagulation cascade. Both can eventually trigger thrombosis and inflammation. Therefore, understanding these initial responses of the body is of great importance for newly developed biomaterials. Subtle modulation of the associated biological processes could optimize clinical outcomes. However, our failure to produce truly blood compatible materials may reflect our inability to properly understand the mechanisms of thrombosis and inflammation associated with biomaterials. In vitro models mimicking these processes provide valuable insights into the mechanisms of biomaterial-induced complement activation and coagulation. Here, we review (i) the influence of biomaterials on complement and coagulation cascades, (ii) the significance of complement-coagulation interactions for the clinical success of cardiovascular implants, (iii) the modulation of complement activation by surface modifications, and (iv) in vitro testing strategies.