Nitrogen plasma modification boosts up the hemocompatibility of new PVDF-carbon nanohorns composite materials with potential cardiological and circulatory system implants application

Effects of heterogeneous surface characteristics on hemocompatibility and cytocompatibility of bacterial nanocellulose

The surface properties of cardiovascular biomaterials play a critical role in their biological responses. Although bacterial nanocellulose (BNC) materials have exhibited potential applications in cardiovascular implants, the impact of their surface characteristics on biocompatibility has rarely been studied. This study investigated the mechanism for the biocompatibility induced by the physicochemical properties of both sides of BNC. With greater wettability and smoothness, the upper BNC surface reduced protein adsorption by 25 % compared with the lower surface. This prolonged the plasma re-calcification time by 14 % in venous blood. Further, compared with the lower BNC surface, the upper BNC surface prolonged the activated partial thromboplastin time by 5 % and 4 % in arterial and venous blood, respectively. Moreover, the lower BNC surface with lesser rigidity, higher roughness, and sparser fiber structure promoted cell adhesion. The lower BNC surface enhanced the proliferation rate of L929 and HUVECs cells by 15 % and 13 %, respectively, compared with the upper BNC surface. With lesser stiffness, the lower BNC surface upregulated the expressions of CD31 and eNOS while down-regulating the ICAM-1 expression - This promoted the proliferation of HUVECs. The findings of this study will provide valuable insights into the design of blood contact materials and cardiovascular implants.

Covalent functionalization of 1D and 2D sp2-carbon nanoallotropes - twelve years of progress (2011-2023)

Carbon nanoallotropes have attracted significant attention in the field of materials science due to their unique combination of physicochemical and biological properties, with numerous applications. One-dimensional (1D) and two-dimensional (2D) sp2-carbon nanoallotropes, such as carbon nanohorns (CNHs), carbon nanotubes (CNTs), and graphene, have emerged as prominent candidates for a variety of technological advancements. To fully exploit their exceptional characteristics, the covalent functionalization of these nanostructures may alleviate the problems with the processing and final performance. This route of the carbon nanoallotrope functionalization is based on a covalent attachment of functional groups or molecules (via linkers of various strengths) to their surfaces, enabling precise control over physical, chemical, biological, and electronic properties. Such an approach opens up new avenues for tailoring the nanoallotrope characteristics, such as solubility/dispersibility, reactivity, and interactions with other materials. Over more than the last decade, significant progress has been made in the covalent functionalization of both 1D and 2D sp2-carbon nanoallotropes, paving the way for diverse applications in the nanoelectronics, energy storage, sensing, and biomedical fields. In this comprehensive review, we provide state-of-the-art advancements and achievements in the covalent functionalization of 1D and 2D sp2-carbon nanoallotropes during the past dozen years. We aim to highlight the key strategies, methodologies, and breakthroughs that have significantly contributed to this field. Eventually, we discuss the implications of those advancements and explore the opportunities for future research and applications.

Effect of the oxygenic groups on activated carbon on its hemocompatibility

In this research, the effect of the oxygenic groups on activated carbon on its hemocompatibility was studied by liquid-phase oxidation to introduce oxygenic groups on its surface and subsequent heat treatment under a nitrogen environment to remove these groups. Hemocompatibility was assessed through coagulation, hemolysis, platelet adhesion, and protein adsorption using rabbit blood samples. Results showed that an increasing presence of oxygenic groups improved hemocompatibility, evidenced by enhanced coagulation, reduced hemolysis, better platelet adhesion, and decreased fetal bovine serum protein adsorption. Conversely, the removal of oxygenic groups diminished hemocompatibility, except for coagulation when groups were removed at 250 ℃ for 15 min. Therefore, this research presents a promising route to enhance the hemocompatibility of activated carbon, offering insights into surface modification for improved biomaterial design.

In vitro evaluation of electrospun polyvinylidene fluoride hybrid nanoparticles as direct piezoelectric membranes for guided bone regeneration

A polyvinylidene fluoride (PVDF) piezoelectric membrane containing carbon nanotubes (CNTs) and graphene oxide (GO) additives was prepared, with special emphasis on the piezoelectric activity of the aligned fibers. Fibroblast viability on membranes was measured to study cytotoxicity. Osteoprogenitor D1 cells were cultured, and mineralization of piezoelectric composite membranes was assessed by ultrasound stimulation. Results showed that the electrospun microstructures were anisotropically aligned fibers. As the GO content increased to 1.0 wt% (0.2 wt% interval), the β phase in PVDF slightly increased but showed the opposite trend with the increase in CNT. Excessive addition of GO and CNT hindered the growth of the β phase in PVDF. The direct piezoelectric activity and mechanical properties showed the same trend as the β phase in PVDF. Moreover, GO/PVDF with the same nanoparticle content showed better performance than CNT/PVDF composites. In this study, a comparison of the generated piezoelectric specific voltage (unit: 10^-3 Vg^-1 cm^-2, linear stretch, g₃₃) with control PVDF only (0.55 ± 0.16) revealed that the two composites containing 0.8 wt% GO- and 0.2 wt% CNT- with 15 wt% PVDF exhibited excellent piezoelectric voltages, which were 3.37 ± 1.05 and 1.45 ± 0.07 (10^-3 Vg^-1 cm^-2), respectively. In vitro cultures of these two groups in contact with D1 cells showed significantly higher alkaline phosphatase secretion than the PVDF only group within 1-10 days of cell culture. Further application of ultrasound stimulation showed that the piezoelectric membrane differentiated D1 cells earlier than without ultrasound and induced higher proliferation and mineralization. This developing piezoelectric effect is expected to generate voltage through activities to enhance microcurrent stimulation in vivo.