Studies On Microchip Bonding Techniques And Fabrication Of Multi-immunochips

Micro total analysis system (μ-TAS) integrates all procedures including sample preparation, reaction, separation, and detection occurring in a common lab onto a chip with a few square centimeters in size, and achieves the various chemical or biological functions by the manipulation of fluid in the micro-channel network throughout the system. The basic characteristics is the flexible combination and integration of many operation units on the tiny platform. It is convenient, fast and low reagent consumption, thus has emerged as a powerful technology with widely applications in disease diagnosis, drug screening, environmental monitoring, food safety and other fields. Therefore, it is of great significance to explore new fabrication methods of microfluidic chips and their applications in bioanalysis. The thesis focuses on microchip bonding techniques and fabrication of multi-immunochips and mainly includes the following aspects:1. One step high quality poly(dimethylsiloxane)-hydrocarbon plastics bondingIn this work, high quality irreversible bonding between poly(dimethylsiloxane)(PDMS) and hydrocarbon plastics (COC, PS, PP) have been realized merely by one step air plasma, with surface geometrical change of less than10nm, which is widely applicable covering the requirement for most micro-nanofluidic chips. By tunning the ratio of oxygen and nitrogen, it is found that synergic effect exists between the two gases during the plasma treatment to the PDMS and plastics, effect of which is over that of merely oxygen or nitrogen. Since air is easy to get, cheap and green, it is selected for futher condition optimization by tuning the power of the plasma. PDMS-PS, PDMS-COC, and PDMS-PP hybrid chips can withstand over500kPa pressure both in gas and liquid form, which is over the requirement for most of the microfludics applications. Further experiments show that the bonding is not degraded over1week storage at temperatures from-20℃to50℃. Its resistance to chemical environment is also strong:no leakage is observed when the chip is filled with1.0M HCl,1.0M NaOH and pure water over3days,7days and one month, respectively.2. ITO Electrode microarray-based multi-immunochipsWe report here a new multi-immuno ECL detection platform integrating ITO electrode microarray and microfluidic chips. We fabricated "petals" ITO electrode microarray by means of screen printing method, which was coated with a PDMS slice containing radial multichannels to generate8independent detection units. Each unit has individual function,3of which were decorated by K-doped graphene-CdS:Eu NCs composite and sequentially functionalized with captured antibody of CEA, AFP and PSA, respectively. When a sandwich structured specific immune response occurred, CdTe QDs labeled antibodies were selectively captured by the corresponding antigens along with ECL quenching.3units were used for control experiments to test selectivity for multiplexed detection in a complex matrix. The remaining2units were used to test the ECL intensity of K-doped graphene-CdS:Eu NCs and the quenching efficiency of CdTe QDs. This platform provides a rapid, simple but sensitive and high-throughput approach with microliter-level sample volume and holds great promise for multiplexed detection of antigens as well as the screening of tumor markers.