Lactate detection in single living cells based on polymer brush modified optical lactate nanosensor

• Main Author: Cao, Jing
• Other Authors: Li Changming
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Science::Medicine::Biosensors
• Online Access: http://hdl.handle.net/10356/39489
• Institution: Nanyang Technological University

The emergence of optical nanosensors through integration of modern biosciences and optical biosensor technology has been one of the most exciting and promising recent developments. The capability to achieve sensitive monitoring of lactate levels in single living cells provides important insights into various cellular physiological processes. In this project we have successfully developed a unique polymer brush modified optical lactate nanosensor for single living cell detection. The polymer brush was grafted onto the nanotip to provide high density of epoxy groups for subsequent covalent immobilization of LDH enzymes. The immobilized LDH enzymes allow the detection of its substrate, lactate, by monitoring the fluorescence of NADH, a product of the reaction between NAD+ and lactate. The detection limit of the as-fabricated nanosensor is calculated to be ca. 68 μM, and the linear response range is up to 3 mM (R2 = 0.981), which is significantly superior to that of the traditional method. Extracellular lactate detections were also carried out at single cell level to investigate and compare the cancer metabolism in MCF7 and MCF7/HER2 breast cancer cells. Our work provides great potentials in broad applications such as biochemical analysis and clinical diagnosis.