The fabrication of tubular structures, with multiple cell types forming different layers of the tube walls, is described using a stress-induced rolling membrane (SIRM). Cell orientation inside the tubes can also be controlled by topographical contact guidance. These layered tubes precisely mimic blood vessels and many other tubular structures, suggesting that they may be of great use in tissue engineering.
A self-adjusting, blood vessel-mimicking, multilayered tubular structure with two polymers, poly(ε-caprolactone) (PCL) and poly(dl-lactide-co-glycolide) (PLGA), can keep the shape of the scaffold during biodegradation. The inner (PCL) layer of the tube can expand whereas the outer (PLGA) layers will shrink to maintain the stability of the shape and the inner space of the tubular shape both in vitro and in vivo over months. This approach can be generally useful for making scaffolds that require the maintenance of a defined shape, based on FDA-approved materials.
We report a one-step method to fabricate necklace-like structures from zero-dimensional materials via electrospinning. PVA was used as polymer matrix for accomplishing necklace-like arrays of silica particles. We systemically investigated how the diameter of SiO(2) particles, the weight ratio of PVA to SiO(2), the voltage, and the relative content of PVA/SiO(2)/H(2)O influenced the morphology of electrospun fibers. SiO(2) particles with diameter of 143 nm tended to aggregate into bunches in the fibers, while 265 and 910 nm SiO(2) particles tended to align along the fibers one by one, resembling necklaces. The content of water in the PVA/SiO(2)/H(2)O solution showed critical influence on the diameter of fibers and consequently determined the morphology. Too thin solutions gave birth to blackberry-like structure; too condensed solution was too hard to eject from the orifice of the needle; when the ingredient was elaborately tailored, we obtained necklace-like structures. We believe that these results can serve as references to generating other complex structures involving polymers and particles via electrospinning and that these structures will be potentially useful in photoelectric devices, drug release, and optical components.
Fabrication of poly(dimethylsiloxane) (PDMS)/poly(methyl methacrylate) (PMMA) nanofibers is critical to harness the advantage of nanostructured membrane applied in protein microarrays. Electrospinning (ES) of PDMS nanofibers is challenging because of the relatively low molecular weight of PDMS prepolymer. We report a strategy to fabricate PDMS/PMMA nanofibers via ES by introducing carrier polymer PMMA into PDMS solutions to supplement the deficiency of chain entanglements in the PDMS prepolymer. The prepared PDMS/PMMA nanofibrous membrane (PDMS/PMMA NFM) was successfully used as substrates for protein microarrays. The results of immunoassays showed the superior performance of PDMS/PMMA NFM as 3D substrate for protein microarrays; the limit-of-detection (LOD) on PDMS/PMMA NFM was 32 times lower than that on nitrocellulose membrane. The realization of ES PDMS extends the scope of ES materials from thermoplastic polymers to thermosetting materials. Given the simplicity, low cost, and high efficiency of ES technology, we believe that PDMS/PMMA NFM is a promising 3D substrate for protein microarrays.
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