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Hamid Q.,Drexel University | Wang C.,Drexel University | Snyder J.,Drexel University | Williams S.,Drexel University | And 4 more authors.

The utilization of the microfabrication technique to fabricate advanced computing chips has exponentially increased in the last few decades. Needless to say, this fabrication technique offers some unique advantages to develop micro-systems. Though many conventional microfabrication techniques today uses very harsh chemicals, the authors believe that the manipulation of system components and fabrication methods may aid in the utilization of the microfabrication techniques used in fabricating computer chips to develop advanced biological microfluidic systems. Presented in this paper is a fabrication approach in which popular fabrication methods and techniques are coupled together to develop an integrated system that aids in the fabrication of cell-laden microfluidic systems. This system aims to reduce the uses of harsh chemicals and decreases the lengthy fabrication time. Additionally, this integrated system will enable the printing of cells as the microfluidic chip is being fabricated. To demonstrate the unique capabilities of the integrated system, an advanced microfluidic chip is being fabricated and investigated. The advanced chip will feature the investigation of cancer cells in a co-cultured microfluidic environment. The investigations presented demonstrate co-cultures in a microfluidic chip, advanced cell printing with localized surface enhancement, cell integration, and full additive fabrication of a microfluidic chip. © 2015 IOP Publishing Ltd. Source

Hamid Q.,Drexel University | Wang C.,Drexel University | Snyder J.,Drexel University | Sun W.,Drexel University | And 2 more authors.
Journal of Biomedical Materials Research - Part B Applied Biomaterials

Advances in micro-electro-mechanical systems (MEMS) have led to an increased fabrication of microchannels. Microfabrication techniques are utilized to develop microfluidic channels for continuous nutrition supply to cells inside a micro-environment. The ability of cells to build tissues and maintain tissue-specific functions depends on the interaction between cells and the extracellular matrix (ECM). SU-8 is a popular photosensitive epoxy-based polymer in MEMS. The patterning of bare SU-8 alone does not provide the appropriate ECM necessary to develop microsystems for biological applications. Manipulating the chemical composition of SU-8 will enhance the biological compatibility, giving the fabricated constructs the appropriate ECM needed to promote a functional tissue array. This article investigates three frequently used surface treatment techniques: (1) plasma treatment, (2) chemical reaction, and (3) deposition treatment to determine which surface treatment is the most beneficial for enhancing the biological properties of SU-8. The investigations presented in this article demonstrated that the plasma, gelatin, and sulfuric acid treatments have a potential to enhance SU-8's surface for biological application. Of course each treatment has their advantages and disadvantages (application dependent). Cell proliferation was studied with the use of the dye Almar Blue, and a micro-plate reader. After 14 days, cell proliferation to plasma treated surfaces was statistically significantly enhanced (p < 0.00001), compared to untreated surfaces. The plasma treated surface is suggested to be the better of the three treatments for biological enhancement followed by gelatin and sulfuric acid treatments, respectively. © 2014 WILEY PERIODICALS INC. Source

Hamid Q.,Drexel University | Wang C.,Drexel University | Zhao Y.,Tsinghua University | Snyder J.,Drexel University | And 3 more authors.

Three-dimensional tissue platforms are rapidly becoming the method of choice for quantification of the heterogeneity of cell populations for many diagnostic and drug therapy applications. Microfluidic sensors and the integration of sensors with microfluidic systems are often described as miniature versions of their macro-scale counterparts. This technology presents unique advantages for handling costly and difficult-to-obtain samples and reagents as a typical system requires between 100 nL to 10 μL of working fluid. The fabrication of a fully functional cell-based biosensor utilizes both biological patterning and microfabrication techniques. A digital micro-mirror (photolithographic) system is initiated to construct the tissue platform while a cell printer is used to precisely embed the cells within the construct. Tissue construct developed with these technologies will provide an early diagnostic of a drug's potential use. A three-dimensional interconnected microfluidic environment has the potential to eliminate the limitations of the traditional mainstays of two-dimensional investigations. This paper illustrates an economical and an innovative approach of fabricating a three-dimensional cell-laden microfluidic chip for detecting drug metabolism. © 2014 IOP Publishing Ltd. Source

Hamid Q.,Drexel University | Wang C.,Drexel University | Zhao Y.,Tsinghua University | Snyder J.,Drexel University | And 3 more authors.
Journal of Manufacturing Science and Engineering, Transactions of the ASME

Micro-electromechanical systems (MEMS) technologies illustrate the potential for many applications in the field of tissue engineering, regenerative medicine, and life sciences. The fabrication of tissue models integrates the multidisciplinary field of life sciences and engineering. Presently, monolayer cell cultures are frequently used to investigate potential anticancer agents. These monolayer cultures give limited feedback on the effects of the micro-environment. A micro-environment, which mimics that of the target tissue, will eliminate the limitations of the traditional mainstays of tissue research. The fabrication of such micro-environment requires a thorough investigation of the actual target organ, and or tissue. Conventional MEMS technologies are developed for the fabrication of integrated circuits on silicon wafers. Conventional MEMS technologies are very expensive and are not developed for biological applications. The digital micromirroring microfabrication (DMM) system eliminates the need for an expensive chrome mask by incorporating a dynamic mask-less fabrication technique. The DMM is designed to utilize its digital micromirrors to fabricate of biological devices. This digital microfabrication system provides a platform for the fabrication of economic biological microfluidics that is specifically designed to mimic the in vivo conditions of the tissue of interest. Investigations portrayed in this paper demonstrate the DMM capabilities to develop biological microfluidics. Though the applications of the DMM are extensive, the simple sinusoidal microfluidic characterized in this paper illustrates the DMM capabilities to develop biological microfluidic chips. Copyright © 2014 by ASME. Source

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