In this paper, we reported a new approach for particle assembly with acoustic tweezer during three-dimensional (3D) printing for the fabrication of embedded conductive wire with 3D structures. A hexagon shaped acoustic tweezer was incorporated with Digital Light Processing (DLP) based stereolithography (SLA) printer to pattern conductive lines via aligning and condensing conductive nanoparticles. The effect of filler content on electrical resistivity and pattern thickness were studied for copper, magnetite nanoparticles, and carbon nanofiber reinforced nanocomposite samples. The obtained data was later used to produce examples of conductive 3D microstructures and embedded electronic components by using the suggested method.

Abstract3D printing of composite materials offers an opportunity to combine desired properties of composite materials with flexibility of additive manufacturing in geometric shape and complexity. In this paper, shear-induced alignment of aluminum oxide nanowires during stereolithography printing was utilized to fabricate a nanowire reinforced polymer composite. To align the fibers, a lateral oscillation mechanism was implemented and combined with wall pattern printing technique to generate shear flow in both vertical and horizontal directions. A series of specimens were fabricated for testing the composite material's tensile strength. The results showed that mechanical properties of the composite were improved by reinforcement of nanofibers through shear induced alignment. The improvement of tensile strength was approximately ~28% by aligning the nanowires at 5wt% (~1.5% volume fraction) loading of aluminum oxide nanowires.

A wavy-herringbone (wavy-HB) structured microfluidic device was used to effectively and selectively capture and release circulating tumor cells (CTCs) by using immunoaffinity and magnetic force. This device was designed to create passive turbulence and increase the possibility of tumor cells colliding with the device wall. Under an external magnetic field, magnetic particles (MPs) coated with anti-EpCAM against a tumor cell surface protein (EpCAM) were immobilized over the wavy-HB surface to capture tumor cells. After removing the magnetic field, the captured cells with surplus MPs were released from the device and collected; thus, these cells could be re-cultured for further analysis. Under optimized conditions, the capture efficiency of the tumor cells can be as high as 92% ± 2.8%. Capture experiments were also performed on whole blood samples, and the capture efficiency was in a high range of 81-95%, at different tumor cell concentrations. Such a method can potentially be used for CTC sorting from patient blood samples, CTC concentration monitoring, therapeutic guidance and drug dosage choice, and further study of tumors, such as drug screening and tumor mutations.