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Despite significant progress over the past few decades, creating a tissue-engineered vascular graft with replicated functions of native blood vessels remains a challenge due to the mismatch in mechanical properties, low biological function, and rapid occlusion caused by restenosis of small diameter vessel grafts (<6 mm diameter). A scaffold with similar mechanical properties and biocompatibility to the host tissue is ideally needed for the attachment and proliferation of cells to support the building of engineered tissue. In this study, pectin hydrogel nanofiber scaffolds with two different oxidation degrees (25 and 50%) were prepared by a multistep methodology including periodate oxidation, electrospinning, and adipic acid dihydrazide crosslinking. Scanning electron microscopy (SEM) images showed that the obtained pectin nanofiber mats have a nano-sized fibrous structure with 300–400 nm fiber diameter. Physicochemical property testing using Fourier transform infrared (FTIR) spectra, atomic force microscopy (AFM) nanoindentations, and contact angle measurements demonstrated that the stiffness and hydrophobicity of the fiber mat could be manipulated by adjusting the oxidation and crosslinking levels of the pectin hydrogels. Live/Dead staining showed high viability of the mesenchymal stem cells (MSCs) cultured on the pectin hydrogel fiber scaffold for 14 days. In addition, the potential application of pectin hydrogel nanofiber scaffolds of different stiffness in stem cell differentiation into vascular cells was assessed by gene expression analysis. Real-time polymerase chain reaction (RT-PCR) results showed that the stiffer scaffold facilitated the differentiation of MSCs into vascular smooth muscle cells, while the softer fiber mat promoted MSC differentiation into endothelial cells. Altogether, our results indicate that the pectin hydrogel nanofibers have the capability of providing mechanical cues that induce MSC differentiation into vascular cells and can be potentially applied in stem cell-based tissue engineering.

Bioactive ceramic/glass (BCG) and its derivations have received extensive investigations and clinical applications in hard tissue substitution and regeneration. This review presents the patents on the state of art of the preparation of BCG and its application in tissue engineering and drug delivery. Most of the important patents and journal reports in last 10 years are covered in this paper. The discussions are concentrated on the preparation of various BCG materials with different architectures and functions. Special attention is paid to the recent developments in BCG cement, BCG coating, mesoporous BCG, nanoscale composite of BCG and biodegradable polymers, stimuli responsive BCG hydrogel, and homogeneously mineralized self-assembled peptide-amphiphile (PA) nanofiber-hydroxyapatite composite. Among others, development of highly ordered mesoporous BCG is highlighted as a breakthrough in the history of BCG due to its great potential in controlled delivery system for bioactive molecules in bone tissue regeneration. The nanocomposite of BCG and polymer is also considered as one of promising biomaterials due to its capability for using as the biomedical devices in load bearing bone tissue fixation and substitution. The valuable future investigations on BCG are also speculated in this review.

Atherosclerosis remains a major cause of cardiovascular disease. It is well known that the cholesterol accumulated in the macrophage-derived foam cells is the major component of atherosclerotic plaque. However, the growing evidence suggests that about 40% of the total foam cells in the atherosclerotic plaque were vascular smooth muscle cells (VSMCs)-derived. VSMCs are the major cellular components of arterial wall and undergo phenotypic switching from a functional contractile phenotype to a synthetic proliferative phenotype during the development of atherosclerosis. In addition, the surrounding environment of VSMCs within vascular wall changes with alterations in extracellular matrix (ECM) stiffness and composition. The main goal of this study is to test hypothesis that VSMC mechanics undergoes significant changes in response to these surrounding microenvironment alteration in the progression of atherosclerosis. We employed an innovative approach integrating a series of novel experimental approaches and data-driven mathematical models to monitor the real time mechanics of VSMCs isolated from western diet fed apolipoprotein-E knockout (ApoE-/-) and wild type (WT) mice. The results demonstrated significant differences in the actin cytoskeletal organization and cell mechanics between ApoE-/-VSMCs and WT cells, which may trigger the VSMC migration and contribute to the formation of the arterial plaque. These interesting finding will lead to a novel therapeutic strategy for the pharmaceutical treatment of atherosclerosis by interfering the alteration in VSMC mechanics.

Rice‐shaped bioactive ceramic nanoparticles of 70 nm average diameter and around 200 nm length were produced by an improved sol‐gel method. In comparison to most traditional bioactive glass/ceramic materials, this novel bioactive ceramic contains a significant lower quantity of silicon and higher content of phosphorous. In vitrobioactivity tests showed that this new class of materials can induce the deposition of an apatite layer from simulated body fluid, having the potential to be used in both conventional orthopedic applications or in bone tissue engineering when incorporated in composite scaffolds.

A new surface modification method of hydroxyapatite nanoparticles (n‐HA) by surface grafting reaction of L‐lactic acid oligomer with carboxyl terminal (LAc oligomer) in the absence of any catalyst was developed. The LAc oligomer with a certain molecular weight was directly synthesized by condensation of L‐lactic acid. Surface‐modified HA nanoparticles (p‐HA) were attested by Fourier transformation infrared spectroscopy, 31P MAS‐NMR, and thermal gravimetric analysis (TGA). The results showed that LAc oligomer could be grafted onto the n‐HA surface by forming a Ca carboxylate bond. The grafting amount of LAc oligomer was about 13.3 wt %. The p‐HA/PLLA composites showed good mechanical properties and uniform microstructure. The tensile strength and modulus of the p‐HA/PLLA composite containing 15 wt % of p‐HA were 68.7 MPa and 2.1 GPa, respectively, while those of the n‐HA/PLLA composites were 43 MPa and 1.6 GPa, respectively. The p‐HA/PLLA composites had better thermal stability than n‐HA/PLLA composites and neat PLLA had, as determined by isothermal TGA. The hydrolytic degradation behavior of the composites in phosphate buffered saline (PBS, pH 7.4) was investigated. The p‐HA/PLLA composites lost their mechanical properties more slowly than did n‐HA/PLLA composites in PBS because of their reinforced adhesion between the HA filler and PLLA matrix. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5177–5185, 2005

The cover of Advanced Biomaterials shows Rice‐shaped bioactive ceramic nanoparticles with 70 nm in average diameter and around 200 nm in length were produced by an improved sol‐gel method. In comparison to most traditional bioactive glass/ceramic materials this novel bioactive ceramic contains a significant lower quantity of silicon and higher content of phosphorous. In vitro bioactivity test showed that this new class of materials can induce the deposition of an apatite layer from SBF solution, having potential to be used in both conventional orthopedic applications or in bone tissue engineering when incorporated in composite scaffolds. More information can be found in the article of J. F. Mano et al. on page B25.