Materials science & engineering. C, Materials for biological applications最新文献

In recent years, magnesium alloys (MgA) have been reckoned as the most promising material of biomedical importance on account of its excellent degradable properties and mechanical properties mimicking natural bone tissues. However, MgA are prone to rapid corrosion under physiological conditions, causing toxicity around the neighboring tissues. In addition, they are susceptible to bacterial colonization, a detrimental factor for medical causes. In this study, antibacterial material coated hydrogel-based micro-patterns were developed on MgA to achieve long-term antibacterial, antifouling, osteogenic, and cell-compatible properties. First, the Mg(OH)₂ nanosheet coating was prepared on the surface of MgA as a physical barrier to prevent the corrosion of MgA. Then the hydrogel micropatterns of poly(alendronate sodium methacrylate)/poly(dimethyldiallylammonium chloride)/poly(ethylene glycol) diacrylate (PALNMA/PDADMAC/PEGDA) of different sizes were constructed on the surface of the Mg(OH)₂ coating using the photomask method. Finally, an intelligently responsive antibacterial material hyaluronic acid/berberine (HA/BBR) was coated on MgA-Mg(OH)₂-PALNMA/PDADMAC/PEGDA patterns via layer-by-layer self-assembly. The excellent antifouling performance of the samples is attributed to the topological structure of the pattern. Interestingly, as the pattern size of PALNMA/PDADMAC/PEGDA decreases, the antibacterial, antifouling, and cell compatibility properties of the samples gradually improve. UV–Vis spectra and bacterial plate count indicate that HA/BBR coating provide a pH and hyaluronidase (HAase) dual-responsive surface to kill the attached bacteria quickly. Finally, the in vitro experiments demonstrate excellent blood compatibility, cell compatibility and osteogenic properties of the modified MgA samples. Therefore, the intelligent multifunctional assembly of MgA presented here has a promising future in the field of metal implant materials.

Electrohydrodynamic (EHD) processes are promising healthcare fabrication technologies, as evidenced by the number of commercialised and food-and-drug administration (FDA)-approved products produced by these processes. Their ability to produce both rapidly and precisely nano-sized products provides them with a unique set of qualities that cannot be matched by other fabrication technologies. Consequently, this has stimulated the development of EHD processing to tackle other healthcare challenges. However, as with most technologies, time and resources will be needed to realise fully the potential EHD processes can offer. To address this bottleneck, researchers are adopting machine learning (ML), a subset of artificial intelligence, into their workflow. ML has already made ground-breaking advancements in the healthcare sector, and it is anticipated to do the same in the materials domain. Presently, the application of ML in fabrication technologies lags behind other sectors. To that end, this review showcases the progress made by ML for EHD workflows, demonstrating how the latter can benefit greatly from the former. In addition, we provide an introduction to the ML pipeline, to help encourage the use of ML for other EHD researchers. As discussed, the merger of ML with EHD has the potential to expedite novel discoveries and to automate the EHD workflow.

Bone defect augmentation with synthetic materials is crucial due to the unavoidable limitations of auto- and allografting. Although there are different promising synthetic materials for filling bone defects, the functionalization of these materials with cells is still challenging due to the lack of ideal cell sources. Here, we used stromal vascular fraction (SVF) heterogeneous cells that could be obtained from autologous adipose tissue to functionalize hyaluronic acid/gelatin-biphasic calcium phosphate (HyA-Gel/BCP) scaffolds for bone regeneration. The SVF cells were isolated, and the cellular composition and osteogenic differentiation potential were analyzed. Then, they were cultured on HyA-Gel/BCP scaffolds for in vitro characterization. An In vivo evaluation of the autologous SVF-loaded HyA-Gel/BCP scaffolds was performed using a rat skull critical-size defect model. The results showed that the SVF was successfully isolated and contained different types of cells, including mesenchymal stem like-cells with osteogenic differentiation ability. Also, the SVF cells could be cultured and expanded on the HyA-Gel/BCP scaffolds without affecting their viability. In vivo implantation of autologous SVF-loaded HyA-Gel/BCP scaffolds showed excellent bone regeneration compared to unloaded HyA-Gel/BCP scaffolds. Thus, autologous SVF-loaded HyA-Gel/BCP scaffolds could be a promising transplantable bone grafting material for bone tissue engineering.

Interactions of nanoparticles (NPs) with lipid membranes have enormous biological implications especially for gene delivery applications. In this work, using all-atom steered- and molecular dynamics simulations, we investigated deformation of lipid membranes and pore closure during a NP penetration process. Three membrane bilayer models built from 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC), dipalmitoylphosphatidylcholine (DPPC) and dilauroylphosphatidylcholine (DLPC), and a NP formed by 2 short interfering RNA (siRNA) and 6 polyethylenimine (PEI) molecules were used. Our results showed that different membrane lipids could lead to differences in pore formation (symmetric vs. asymmetric), and could undergo different levels of pore-mediated flip-flops during the closure. DLPC showed the largest number of flip-flops among the three lipid membranes. In addition, introduction of hydrophobic linoleic acid (LA) substitution onto the PEIs was found to facilitate pore formation, since the long LA tails could insert themselves into the hydrophobic region of the membrane where the lipid tails were less aligned. Compared with DPPC, POPC and DLPC membranes had less alignment of lipid tails in the bilayer, which promoted the insertion of LA tails and hence NP entry into the cell. Our observations provide valuable insight into the membrane deformations and pore dynamics during NP penetration and will be important for the design of NP carriers for effective gene delivery.

Medical device infections have now become the major burden of healthcare, and particular administration of combating bacterial infections is of significance. In this work, robust nanoparticles-stacked superhydrophilic coatings were established through the rapid oxidation, cross-linking and aggregation of dopamine in the presence of sodium periodate. The robust superhydrophilicity was achieved and maintained due to the hydrophilic chemical components together with the micro/nano topological structure stacked by nanoparticles, resulting in an impressive nonfouling performance for proteins adsorption. Moreover, due to the presence of aromatic catechol moieties, antibiotics (e.g. norfloxacin and cephalexin) were deposited into the superhydrophilic coating in situ, by π-π stacking/hydrophobic interactions, endowing the surface with antibacterial ability. Interestingly, the superhydrophilic coatings showed a safe and effective antibacterial ability in a low dose-dependent manner because of the nonfouling platform supported killing and releasing of bacteria. The in vivo cutaneous wound healing evaluation in rats further demonstrated the synchronous effect of anti-infection and promoting wound healing. Such superhydrophilicity supported nonfouling platform was believed to open a new window to modify biomedical devices combined with wound healing and antibacterial properties.

Biomimetic surface coatings can be combined with conventional implants to mimic the extracellular matrix (ECM) of the surrounding tissue to make them more biocompatible. Layer-by-layer technique (LbL) can be used for making surface coatings by alternating adsorption of polyanions and polycations from aqueous solutions without need of chemical reactions. Here, polyelectrolyte multilayer (PEM) systems is made of hyaluronic acid (HA) as polyanion and Collagen I (Col) as polycation to mimic the ECM of connective tissue. The PEM are combined with dexamethasone (Dex)-loaded liposomes to achieve a local delivery and protection of this drug for stimulation of osteo- and chondrogenic differentiation of multipotent stem cells. The liposomes possess a positive surface charge that is required for immobilization on the PEM. The surface properties of PEM system show a positive zeta potential after liposome adsorption and a decrease in wettability, both promoting cell adhesion and spreading of C3H10T1/2 multipotent embryonic mouse fibroblasts. Differentiation of C3H10T1/2 was more prominent on the PEM system with embedded Dex-loaded liposomes compared to the basal PEM system and the use of free Dex-loaded liposomes in the supernatant. This was evident by immunohistochemical staining and an upregulation of the expression of genes, which play a key role in osteogenesis (RunX2, ALP, Osteocalcin (OCN)) and chondrogenesis (Sox9, aggrecan (ACAN), collagen type II), determined by quantitative Real-time polymerase chain reaction (qRT-PCR) after 21 days. These findings indicate that the designed liposome-loaded PEM system have high potential for use as drug delivery systems for implant coatings that can induce bone and cartilage differentiation needed for example in osteochondral implants.