Capillary-driven automatic packaging.

Packaging continues to be one of the most challenging steps in micro-nanofabrication, as many emerging techniques (e.g., soft lithography) are incompatible with the standard high-precision alignment and bonding equipment. In this paper, we present a simple-to-operate, easy-to-adapt packaging strategy, referred to as Capillary-driven Automatic Packaging (CAP), to achieve automatic packaging process, including the desired features of spontaneous alignment and bonding, wide applicability to various materials, potential scalability, and direct incorporation in the layout. Specifically, self-alignment and self-engagement of the CAP process induced by the interfacial capillary interactions between a liquid capillary bridge and the top and bottom substrates have been experimentally characterized and theoretically analyzed with scalable implications. High-precision alignment (of less than 10 µm) and outstanding bonding performance (up to 300 kPa) has been reliably obtained. In addition, a 3D microfluidic network, aligned and bonded by the CAP technique, has been devised to demonstrate the applicability of this facile yet robust packaging technique for emerging microfluidic and bioengineering applications.

Three-dimensional surface microfluidics enabled by spatiotemporal control of elastic fluidic interface.

As an emerging alternative to the conventional counterpart, surface microfluidics incorporates both intrinsic resistive solid-liquid and elastic frictionless gas-liquid interfaces, leading to unique flow-pressure characteristics. Furthermore, the open-surface microfluidic platforms can be fabricated on a monolithic substrate with high wettability contrast by the previously reported one-step lithographic process of a photosensitive superhydrophobic nanocomposite material, which permits flexible fluidic operations and direct surface modifications. In the paper, we first present three-dimensional microfluidic manipulations utilizing the unconventional gas-liquid interfaces of surface microfluidics, outlined by the micropatterned wetting boundaries (also known as the triple lines). In contrast to the primary linear (resistive) nature of the conventional closed-channel microfluidics, the distinct elastic interface of surface microfluidics enables remarkable three-dimensional (deformable) and time-dependent (capacitive) operations of the flow. Specifically, spatiotemporal dependence of microflow patterns on the planar fluidic surfaces has been theoretically analyzed and experimentally characterized. Utilizing the unconventional interface-enabled flow-pressure relationship, novel surface fluidic operations, including microflow regulation and flow-controlled switching, have been demonstrated and fully investigated. Furthermore, three-dimensional surface microfluidic networks together with analog-to-digital stereo-flow activations have been established, in which miniature capillary bridges form fluidic connections between two independent surface microfluidic circuits.

[Three-dimensional finite analysis of the application of attachment for restoration of unilateral maxillary defect].

PURPOSE: To study the stress of the application of attachment for restoration of unilateral maxillary defect. METHODS: Using the 3-D FE model of the unilateral maxillary defect, two different 3-D FE models of the application of attachment framework for restoration of different unilateral maxillary defects (attachment on the mesial side of the central incisor or canine) were designed and established. RESULTS: The area of stress concentration of the two prostheses were on the palatal base near the position of the anterior teeth. The stress was on the posterior teeth of the healthy side. When the attachment was on the mesial side of the central incisor, the stress of the mesial surface of the central incisor was 1.306MPa, and the stress concentration was at the junction of the attachment and the lingual guide plane. When the attachment was on the mesial of the canine, the stress of the mesial surface of the canine was 0.797MPa, and stress concentration was at the corner of the front and bottom of the lingual guide plane. CONCLUSIONS: The application of attachment for restoration of unilateral maxillary defect meets the biomechanical demands without increasing the stress load on the abutment. And further study of the design of the attachment framework should be done.

[The construction and analysis of three-dimensional finite element model of human unilateral maxillary defect].

PURPOSE: To built a three-dimensional finite element model of the common unilateral maxillary defect, and to study the stress of the traditional maxillofacial prostheses for unilateral maxillary defect. METHODS: The three-dimensional finite element model of unilateral maxillary defect and maxillofacial obturator prosthesis were constructed by means of spiral CT scanning, digital image transfer, self-developed software MedGraphics, UG engineering design program and ANASYS software. Then 3-D finite element stress analysis was carried out, for the prosthesis. RESULTS: The three-finite element models of the unilateral maxillary defect and maxillofacial obturator prosthesis were established. In the traditional obturator prosthesis, the stress was on the posterior teeth of the healthy side; the area of stress concentration was on the palatal base near the position of the anterior teeth. CONCLUSIONS: The three-dimensional finite element models of the unilateral maxillary defect and maxillofacial obturator prosthesis have good similarity in geometry and biology. The obturator prosthesis is in accorded with the biomechanical demands.