Epithelial-adipose interaction is an integral step in breast cancer cell invasion and progression towards lethal metastatic disease. Understanding the physiological contribution of obesity, a major contributor to breast cancer risk and negative prognosis in post-menopausal patients, on cancer cell invasion requires detailed co-culture constructs that reflect mammary microarchitecture. Using laser direct-write, a laser-based CAD/CAM bioprinting technique, we have demonstrated the ability to construct breast cancer cell-laden hydrogel microbeads into spatially defined patterns in hydrogel matrices containing differentiated adipocytes. Z-stack imaging confirmed the three-dimensional nature of the constructs, as well as incorporation of cancer cell-laden microbeads into the adipose matrix. Preliminary data was gathered to support the construct as a potential model for breast cancer cell invasion into adipose tissue. MCF-7 and MDA-MB-231 breast cancer cell invasion was tracked over 2 weeks in an optically transparent hydrogel scaffold in the presence of differentiated adipocytes obtained from normal weight or obese patient tissue. Our model successfully integrates adipocytes and gives us the potential to study cellular and tissue-level interactions towards the early detection of cancer cell invasion into adipose tissue.

Current limitations to the engineering of ex vivo and in vitro neural environments are hampering the ability to understand underlying neurophysiology. High levels of spatial specificity, reproducibility and viability have been previously reported using laser direct write (LDW) to print cells. However, despite the significant need no one has yet reported laser assisted printing of primary mammalian neuronal cells, an inherently sensitive but critically important population. Herein, we describe the use of LDW to reproducibly and accurately pattern viable dorsal root ganglion (DRG) neurons and supportive cells capable of neural outgrowth and network formation. Our demonstrated ability to engineer and control distinct micro-environmental components unlocks the potential for high throughput experiments to both understand underlying physiology and investigate therapeutic interventions.

Laser-based three-dimensional (3D) printing methods, including laser direct-write cell printing and two-photon polymerization, have seen significant advances because of their unique photonic characteristics. Several mechanisms have been developed to increase the overall throughput of two-photon polymerization. Recent efforts to develop complex medically relevant structures using laser direct-write cell printing have also been demonstrated; for example, an ex vivo experimental platform for time-lapse imaging of cancer cell dynamics during angiogenesis within a microvascular network, which combines laser direct-write cell printing into the rat mesentery culture model; a model that simulates a 3D in vivo culture. Laser 3D printing methods hold significant promise for 3D printing of tissue engineering scaffolds, microstructured medical devices, and other medically relevant structures.

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Direct integration of proton conductor films on Pt-coated substrates opens the way to film-based proton transport devices. Columnar SrZr0.95Y0.05O3−δ (SZY) films with dense microstructure were deposited on Pt-coated MgO(100) substrates at 830 °C by pulsed laser deposition. The optimal window of ambient O2 pressure for good crystallinity of SZY films is from 400 to 600 mTorr. The ambient O2 compresses the plasma plume of SZY and increases the deposition rate. The 10 nm thick Ti adhesion layer on MgO(100) greatly affects the orientation of the sputtered Pt layers. Pt deposited directly on MgO shows a highly (111)-preferred orientation and leads to preferentially oriented SZY films while the addition of a Ti adhesion layer makes Pt show a less preferential orientation that leads to randomly oriented SZY films. The RMS surface roughness of preferentially oriented SZY films is larger than that of randomly oriented SZY films deposited under the same ambient O2 pressure. As the O2 pressure increased, the RMS surface roughness of preferentially oriented SZY films increased, reaching 45.7 nm (2.61% of film thickness) at 600 mTorr. This study revealed the ambient O2 pressure and orientation dependent surface roughness of SZY films grown on Pt-coated MgO substrates, which provides the potential to control the surface microstructure of SZY films for electrochemical applications in film-based hydrogen devices.

We have explored the energy storage capability of Ba0·5Sr0 ·5TiO3 (BST)–polyvinylidene fluoride (PVDF) nanocomposites. Morphologically uniform BST colloidal nanocubes were prepared in high yield by a solvothermal method at temperatures as low as 150°C. As-synthesised BST nanocubes were used as fillers (35 vol%) in PVDF polymer matrix. The unique dielectric-polymer films show enhanced dielectric constant (>27) and enhanced electrical breakdown strength (Eb) (2·85 MV/cm). The resulting dielectric energy density for BST–PVDF is 9·7 J/cm3, which is a result of the interplay between dependencies of permittivity and breakdown strength on volume fraction. We propose that the strong nanoparticle–polymer matrix interfacial interaction is the main reason for the observed improved dielectric properties. This wet-chemical-assisted fabrication approach can be readily extended to other combinations of polymers and ceramics with concomitant improvement in properties. Key parameters of various materials (e.g. chemical composition, shape, size and surface reactivity) can be readily controlled in this method, opening up a new pathway to highly flexible macroelectronics.