Surface chemistry- and nanomaterials-enhanced high performance protein microarrays

• Main Author: Liu, Yingshuai
• Other Authors: Li Changming
• Format: Theses and Dissertations
• Language: English
• Published: 2011
• Subjects: DRNTU::Science::Medicine::Biosensors; DRNTU::Science::Chemistry::Physical chemistry::Surface chemistry
• Online Access: https://hdl.handle.net/10356/45493
• Institution: Nanyang Technological University

There still remain great challenges to improve performance of protein microarrays in practical applications. Objectives of this project are to develop novel surface chemistry- and nanomaterials-based signal enhancement strategies, and to explore how they improve performance of protein microarrays. First, a poly(glycidyl methacrylate) brush is prepared and used as a supporting matrix, which provides high protein loading capacity, for improving performance of protein microarrays. Printing buffer, probe concentration, and immobilization kinetics are systematically investigated to elucidate fundamentals of protein attachment. The high performance is demonstrated by detections of hepatitis B virus surface antigen (HBsAg) in both phosphate buffered saline (PBS) and human serum. Second, a poly[glycidyl methacrylate-co-poly(ethylene glycol) methacrylate] (P(GMA-co-PEGMA)) brush is in situ synthesized on a poly(methyl methacrylate) (PMMA) substrate and silica nanoparticles (SNP) to synergistically amplify sensitivity of protein microarrays. In this design, the brush-coated SNP could carry a large number of reporter molecules at a single binding event to amplify detection signals, whereas the brush-coated PMMA offers high probe loading capacity and low nonspecific protein adsorption. The sensitivity of protein array is significantly improved. Third, a unique ZnO nanorods-coated substrate is developed to immobilize a large amount of probe molecules and also to directly amplify the microarray fluorescent signals. Two important cancer biomarkers, carcinoembryonic antigen (CEA) and α-fetoprotein (AFP), are analyzed in human serum with a detection limit of 1 pg mL-1, which is comparative to or better than that of ELISA. The advanced ZnO nanorods-based substrate is inexpensive, mass producible, and compatible with well-established microarray printing techniques, providing great potentials for developing economical and sensitive protein arrays. Fourth, a highly sensitive flow-through microarray immunoassay device is developed using a P(GMA-co-PEGMA) brush as a 3-D flexible matrix to achieve large probe loading capacity and a high bioactivity while allowing easy target access to probes in the brush. A limit of detection (LOD) of 1-10 pg mL-1 for detected targets is one to two orders better than those of reported flow-through immunoassays.