Efficient Bacteria Identification using Fluorescent Nanodiamond Labeling and MALDI-TOF MS

• Main Authors: Chiung-Ju Chang, 張瓊如
• Other Authors: Chih-Che Wu
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/20290505371618041470

碩士 === 國立暨南國際大學 === 應用化學系 === 102 === Efficient methods for rapid and accurate identification of bacteria are critical for adequate antibiotic therapy. This study presents a new approach for rapid detection and identification of bacteria using fluorescent nanodiamond labeling and MALDI- TOF MS. 100 nm fluorescent nanodiamonds (FNDs) were surface-functionalized with polyarginine (PA) to manipulate bacterial adhesion through multivalent binding and to act as affinity labeling agents. After a 30-min incubation of PA-coated FNDs with bacteria followed by a short low-speed centrifugation, visible FND-bacterial aggregates were formed at the bottom of the sample vial. Confocal microscopy studies and bacterial adhesion kinetics revealed that both gram-negative bacteria (Escherichia coli) and gram-positive bacteria (Bacillus subtilis) show highly efficient adhesion to the surface of PA-coated FNDs. The FND-bacterial aggregates were further subjected to MALDI-TOF MS analysis for rapid and accurate identification of bacterial species. Bacteria fewer than 105 cells and different species in bacterial mixture (E.coli and B. subtilis) were clearly identified by comparing specific bacterial protein mass patterns. In this study, we demonstrated PA-coated FND is an outstanding affinity probes which is a facile, rapid, culture-free approach for bacteria identification.