Biomedical subjects

Gou-Jen Wang

Publications and source records attributed to Gou-Jen Wang.

6 recordsLinked to original sources

PubMed2006

JSR photolithography based microvessel scaffold fabrication and cell seeding.

A simple and inexpensive lithograph approach, in which the PMMA polymer was selected to be the substrate, the negative photoresist JSR was employed to form the microchannel structure, was adopted to fabricate the microvessel scaffold. In addition, a soft PDMS based microvessel scaffold was built by using a mold that was made up of the negative photoresist JSR. With O(2) plasma treatment, the PDMS based microvessel scaffold became more hydrophilic such that the cell culture could be easier to conduct. During cell culture, it was found that the fabricated scaffold enabled the bovine endothelial cells (BEC) to statically grow. However, the overall exchange of nutrient and oxygen was inefficient. Dynamic seeding by a novel apparatus was further conducted to have better circulation of culture medium. The bovine endothelial cells could successfully be cultivated in the microvessel scaffold by dynamic seeding.

Animals↗

PubMed2006

Structure optimization of microvascular scaffolds.

In this research, a systematic method for the design of a usable microvascular network based on the commercial software FEMLAB is proposed. The design principle comes out to be that the usable network should made up of multi branches with no more than two vertical nodes in individual branch. A special mask was designed to process the microvessel network for experimental verification of velocity uniformity. Accordingly, a simple lithograph approach, in which the PMMA polymer was selected as the substrate, the negative photoresist JSR was employed to form the microchannel structure, was implemented to fabricate the network. Experimental results verified the uniformity of the velocity profile in the microvessel network.

Animals↗

PubMed2006

Controlled porous pattern of anodic aluminum oxide by foils laminate approach.

A novel, much simpler, and low-cost method to fabricate the porous pattern of the anodic aluminum oxide (AAO) based on the aluminum foils laminate approach was carried out. During our experiments, it was found that the pores of the AAO on the upper foil grew bi-directionally from both the top and the bottom surfaces. Experimental results further indicate that the upward porous pattern of the upper foil is determined by the surface structure of the bottom surface of the upper foil. The porous pattern of AAO can be controlled by a pre-made pattern on the bottom surface. Furthermore, no Aluminum (Al) layer removing process is required in this novel laminate method.

Aluminum Oxide↗

PubMed2005

A new mass spectrometry electrospray tip obtained via precise mechanical micromachining.

A new electrospray tip incorporating a beveled edge has been designed for use in plastic electrophoresis chip/electrospray mass spectrometry. Theoretical hydrodynamic analysis has been conducted to model the analytical sensitivity of the spray tip shape. A larger sample wall, that provides increased hydraulic pressure, is recommended in order to preserve the fluid stability at the tip outlet. A polymer with better hydrophobic characteristics than glass was used for the spray tip in order to restrict moisture accumulation at the spray tip outlet. Experimental results demonstrate that the analytical sensitivity of the proposed scheme is better than that obtained using the flat-head tip. Although a tapered capillary tip is commonly used in electrophoresis chip/electrospray mass spectrometry, the proposed tip offers a similar sensitivity while being more rugged and durable than the conventional tapered capillary tip. The cost of our design is also much lower than conventional spray tips.

Electrophoresis, Capillary↗

PubMed2004

Centrifugal and electric field forces dual-pumping CD-like microfluidic platform for biomedical separation.

In this article, we propose a versatile CD-like multi-channel electrophoresis-based biomedical separation system that is driven by the interactive forces between the centrifugal force and the electric field force. The centrifugal force control of this system is realized through the velocity control of a DC servo motor, while the electric field is governed through the concentric conducting circuits, which are suitably designed and fabricated by sputtering on metal mask method, and can be adjusted to provide multi-stage voltages. Experimental results demonstrate that the electro-osmotic flow (EOF) effect can be effectively reduced when the electric field force and centrifugal force are in the opposite direction. Benefits from this are that the electrophoresis separation time can be prolonged and the length of the microfluidic channels can be shortened; therefore, more effective separation efficiency can be obtained. Moreover, other advantages, such as lower joule-heat generation, low-chemistry reaction, and no variation on the ion concentration during processes, make this biomedical separation system more useful.

Biopolymers↗

PubMed2004

Dead volume free micro-machined electro-spray chip for mass spectrometry.

Design and fabrication themes of a dead volume free electro-spray chip for mass spectrometry based on mechanical micro-machining approach is discussed in this article. To implement the dead volume free concept, a cantilever needle is embedded inside the micro-channel of the spray-chip such that there is no connecting joint between the sample wall and the spray-tip. To ensure that the proposed spray-chip is able to produce efficient Taylor cone, embedded needles with different cone angles are fabricated to produce an efficient experiment. Experiments to distinguish amphetamine by a LCQ type mass spectrometry are conducted. Experimental results show that the proposed dead volume free electro-spray chip is able to reach the desired goal. It is also found from the experiments that the ringlike cross-section of the needle embedded micro-channel is critical to the stability of the Taylor cone at the spray-tip. To ensure a stable Taylor cone can be produced at the spray-tip, an embedded needle with a smaller diameter is desired.

Amphetamine↗