Photonic biosensor based on photocorrosion of GaAs/AlGaAs quantum heterostructures for detection of Legionella pneumophila

Abstract

Photocorrosion of semiconductors is strongly sensitive to the presence of surface states, and it could be influenced by electrically charged molecules immobilized near the semiconductor/electrolyte interface. The underlying mechanism is related to band bending of the semiconductor structure near the surface and the associated distribution of excited electrons and holes. The authors have employed photoluminescence of GaAs/AlGaAs quantum heterostructures for monitoring in situ the photocorrosion effect, and demonstrating detection of nongrowing Legionella pneumophila suspended in phosphate buffered saline solution. Antibody functionalized samples allowed direct detection of these bacteria at 10(4) bacteria/ml. The authors discuss the sensitivity of the process related to the ability of creating conditions suitable for photocorrosion proceeding at extremely slow rates and the interaction of an electric charge of bacteria with the surface of a biofunctionalized semiconductor.

Binding strategies for capturing and growing Escherichia coli on surfaces of biosensing devices

“…for wells without Ab as has been reported previously [53]. Other bacteria may have less interaction with NA as it has been demonstrated previously for L. pneumophila [21] and…”

“…Photoluminescence-based biosensors that usually employ GaAs surfaces have been used for detection of some bacteria [19][20][21][22][23][24] allowing quantification down to 10 3 colony forming units of bacteria (CFU) per ml and even lower with chemotaxis [25].…”

Chemotaxis for enhanced immobilization of Escherichia coli and Legionella pneumophila on biofunctionalized surfaces of GaAs

“…We have reported that the lower limit of detection by PL for L. pneumophila was 10 4 CFU/ml. 8 It can be seen that $23 L. pneumophila per mm 2 were immobilized under unassisted conditions at the concentration of 10 4 CFU/ ml. In contrast, this same number of bacteria could be immobilized by a chemotaxis-assisted process from a suspension at $70 CFU/ml, which is 140 times less.…”

“…We have reported that with similar MUDA-antibody or PEG-biotin-neutravidin-biotinylated antibody architectures we were able to detect E. coli at 10 3 CFU/ml, 7 and L. pneumophila at 10 4 CFU/ml. 8 In fact, to ensure PL detection, a critical minimum number of bacteria should be immobilized on the surface. Other detection methodologies also require critical minimum numbers of bacteria immobilized on the surface to yield a positive signal.…”

Модификация Атомной И Электронной Структуры Поверхности Полупроводников А-=sup=-Iii-=/Sup=-В-=sup=-v-=/Sup=- На Границе С Растворами Электролитов О Б З Ор

“…Так, например, свободные концы молекул, адсорбированных на поверхности полупроводника, могут захватывать из раствора детектируемые биомолекулы, вызывая изменение поверхностного заряда, на которое реагирует полупроводниковая наноструктура посредством изменения сигнала ФЛ [162,163]. В частности, на основе квантоворазмерных гетероструктур GaAs/GaAlAs, функционализированных различными органическими молекулами, были созданы эффективные фотолюминесцентные сенсоры кишечной палочки (Escherichia coli) [164,165] и других болезнетворных бактерий [166], а функционализированная тиолами поверхность GaAs(100) в сочетании с наночастицами золота использовалась для фотолюминесцентного распознавания молекул ДНК [167].…”