•Novel type of liquid crystalline substrates (OPC) with tunable storage modulus were fabricated.•OPC mimic in vivo extracellular matrix by exhibiting viscoelasticity and liquid crystalline state.•NIH/3T3s were highly sensitive to the elasticity of OPC substrates.•NIH/3T3s responded to mechanical stimuli of OPC substrates probably through paxillin-ERK pathway.•OPC substrates with intermediate modulus facilitated cellular adhesion and proliferation.The extent of substrate stiffness has been shown to be predominant in regulating cellular behaviors. Previous studies have used matrices such as elastomers or hydrogels to understand cell behavior. Herein, liquid crystalline matrices that resemble movable morphology of biomembrane and viscoelasticity were fabricated with tunable storage modulus for the evaluation of the modulus-driven cell behaviors. Our results demonstrated that NIH/3T3 cells showed a hypersensitive response to the storage modulus of liquid crystalline substrates by the alteration in attachment, spreading, proliferation and viability, polarization, cell cycle and apoptosis, and activity of mechano-transduction-related signal molecules including FAK, paxillin and ERK. The octyl hydroxypropyl cellulose substrates (OPC-1-5) with intermediate storage modulus of 12,312 Pa and 7228 Pa (OPC-2 and OPC-3 respectively) could provide more beneficial adhesion conditions leading to a larger spreading area, more elongated morphology and higher proliferation rates possibly through paxillin-ERK pathway, whereas the substrates with the highest or lowest storage modulus (16,723 Pa, OPC-1; and 41 Pa, OPC-5, respectively) appeared unfavorable for cell growth. Our study provides insights into the mechanism of modulus-driven cellular behaviors for better design of bioengineered cell substrates.

•Chitosan + Sr-doped α-calcium sulfate hemihydrate microcapsules were synthesised.•The novel composite microcapsules had potential application as a bone substitute.•The microcapsules showed controlled degradation and release of strontium ions.•The microcapsules showed in vitro biocompatibility by cytotoxicity test.•The microcapsules showed in vivo biocompatibility in a mouse model.Calcium sulfate is in routine clinical use as a bone substitute, offering the benefits of biodegradability, biocompatibility and a long history of use in bone repair. The osteoconductive properties of calcium sulfate may be further improved by doping with strontium ions. Nevertheless, the high degradation rate of calcium sulfate may impede bone healing as substantial material degradation may occur before the healing process is complete. The purpose of this study is to develop a novel composite bone substitute composed of chitosan and strontium-doped α-calcium sulfate hemihydrate in the form of microcapsules, which can promote osteogenesis while matching the natural rate of bone healing. The developed microcapsules exhibited controlled degradation that facilitated the sustained release of strontium ions. In vitro testing showed that the microcapsules had minimal cytotoxicity and ability to inhibit bacterial growth. In vivo testing in a mouse model showed the absence of genetic toxicity and low inflammatory potential of the microcapsules. The novel microcapsules developed in this study demonstrated suitable degradation characteristics for bone repair as well as favourable in vitro and in vivo behaviour, and hold promise for use as an alternative bone substitute in orthopaedic surgery.

•The heparinization LC substrates were prepared to improve hemocompatibility.•The Hep-OPPCs exhibited liquid crystalline state.•The blood compatibility of the Hep-OPPCs seemed significantly enhanced.•The heparin and liquid crystalline feature produce excellent hemocompatibility.Blood compatibility is of considerable importance in developing medical materials and devices that are in contact with blood. In this work, we successfully developed a novel liquid crystalline heparin-immobilized material (Hep-OPPC) by two-step modification for further improvement of hydrophilicity and hemocompatibility of the liquid crystalline hydroxypropyl cellulose ester (OPCL). The results showed that Hep-immobilization on the OPCL led to dramatic changes in the surface morphology and crystallinity, whereas, the Hep-OPPCs also maintained the liquid crystalline feature at room temperature after heparinization. Furthermore, the hemocompatibility of the Hep-OPPCs was markedly enhanced at low levels of hemolysis assay (HR) with unimpaired erythrocytomorphology, significantly lower concentrations of C3a in blood plasma and remarkable increases in plasma re-calcification time (PRT). This suggests that the heparinized surface could restrict the transformation of fibrinogen with less activation of the intrinsic coagulation system. Moreover, the activated partial thromboplastin time (APTT) and prothrombin time (PT) values of the Hep-OPPCs with low heparin density could also be prolonged in this study suggesting that the liquid crystal feature of the matrix might be blocking the clotting factors. We concluded that the heparin-immobilized liquid crystalline material has the potential to be used in blood-contact materials.

Two types of polyurethane/liquid crystal (PU/LC) composite membranes with different LC contents, namely polyurethane/octyl hydroxypropyl cellulose ester (PU/OPC) and polyurethane/propyl hydroxypropyl cellulose ester (PU/PPC), were prepared and studied. The effects of surface properties on cell compatibility of the membranes were elucidated. PPC tended to assemble to independent phases in the composite membranes, while OPC formed uniformly distributed LC domains. As the introduction of LC, phase separation occurred, and the crystallization of PU was disrupted. The surface of PU/LC composite membranes showed fingerprint texture and two-phase morphology. Hydrophilicity of the two types of composite membranes exhibited a reversal tendency with the increase of LC contents. Cells seeded on the composite membranes presented favorable growth when the content of LC was over 30%, especially on PU/OPC complex. The surface morphology, phase separation between LC and PU as well as the type of LC showed significant effects on the cell behaviors.Highlights► Two types of PU/LC composite membranes with various LC ratios were prepared. ► Surface properties and phase separation varied with the type and ratios of LC. ► Cells presented favorable growth when the content of LC was larger than 30%. ► PU/OPC composite membranes showed better cytocompatibility than PU/PPC.

This paper explores the effects of the incorporation of liquid crystalline phases into polyurethane (PU) matrix with the aim of creating composites with biomimetic surfaces. The surface morphology and phase separation structure of polyurethane/butyl hydroxypropyl cellulose ester (PU/BPC) composite membranes with different BPC contents and underwent different post-treatments were investigated by using polarized optical microscopy (POM), scanning electron microscopy (SEM) and small angle X-ray scattering (SAXS).Well-dispersed liquid crystal (LC) domains occurred on the PU/BPC composite membranes surfaces. As the increment of BPC content, the LC domains tended to form enlarged quasispherical aggregates with poorly molecular orientation, and low degree of regular phase separation occurred between the LC domains and PU substrate. Membranes with different LC contents underwent heat treating and cooling at three different conditions exhibited distinct surface morphologies, meanwhile, a sharp peak emerged in the SAXS pattern, which indicated that the ordered arrangement of BPC molecular chains existed in the LC domains and the phase separation structure between substrate and LC domain had changed. Sharper and more intense SAXS peaks were found in the membranes that annealing in oven, indicating more regular arrangement of LC domains and more obvious phase separation presented than those cooling to 20 °C or −20 °C respectively. Results suggested that the surface morphology of polymer/LC membranes could be controlled through adjusting LC contents or post treatment conditions.Graphical abstractHighlights► Series of PU/LC composite membranes were prepared by solution cast. ► Films underwent heat-treatment at in various conditions. ► Surface properties of the composite membranes varied with the LC ratio. ► Heat-treatment conditions affects the surface properties and phase separation.

Chitosan acetate nano-fibers were fabricated via a solid–liquid phase separation technique. The chitosan acetate structure was influenced by phase separation temperature, chitosan concentration and acetic acid concentration. Uniform nano-fibrous chitosan acetate of 50–500 nm in diameter was engineered at 0.05% (w/v) chitosan and 0.025% (v/v) acetic acid in liquid nitrogen, as opposed to film-shape and micro-fibrous structure at −18 °C and −80 °C respectively. Decreasing the chitosan concentration led to the formation of nano-fibrous/floccules-like structure, while increasing the acetic acid concentration resulted in nano-/micro-fibrous structure instead. The chitosan acetate structure was closely related to the crystallinity varying with different phase separation conditions. Nano-fibrous chitosan acetate showed a medium crystallinity with a glass transition temperature of 155.1 °C and a heat capacity of 29.1 J/g comparing with nano-fibrous/floccules-like and nano-/micro-fibrous samples. The chitosan acetate crystal was also found changeable from form I to form II after solid–liquid phase separation in liquid nitrogen.

Chitosan-based nanocomplexes with various forms were prepared by ionically crosslinking with tripolyphosphate (TPP) in different acidic media under mild conditions. It was found that the self-assembly and ionic interactions of chitosan and TPP were greatly affected by reaction media, and chitosan-based nanofibers could be obtained in adipic acid medium while nanoparticles were formed in acetic acid medium. Using bovine serum albumin (BSA) as a macromolecular model-drug, in vitro drug release studies indicated that chitosan-based nanofibers and nanoparticles exhibited a similar prolonged release profile. In addition, the bioinspired mineralization of both chitosan-based nanofibers and nanoparticles was carried out by soaking them in synthetic body fluids (SBF). Transmission electron microscopy (TEM) and X-ray Diffraction (XRD) results indicated that chitosan-based nanofibers have better inductivity for nano-hydroxyapatite formation than chitosan-based nanoparticles. The results suggested that biomimetic chitosan-based nanofibers with controlled release capacity of bioactive factors may be of use in bone tissue engineering for enhancing the bioactivity and bone inductivity.