title: Protein sensing by nanofluidic crystal and its signal enhancement.
abstract: Nanofluidics has a unique property that ionic conductance across a nanometer-sized confined space is strongly affected by the space surface charge density, which can be utilized to construct electrical read-out biosensor. Based on this principle, this work demonstrated a novel protein sensor along with a sandwich signal enhancement approach. Nanoparticles with designed aptamer onside are assembled in a suspended micropore to form a 3-dimensional network of nanometer-sized interstices, named as nanofluidic crystal hereafter, as the basic sensing unit. Proteins captured by aptamers will change the surface charge density of nanoparticles and thereby can be detected by monitoring the ionic conductance across this nanofluidic crystal. Another aptamer can further enlarge the variations of the surface charge density by forming a sandwich structure (capturing aptamer/protein/signal enhancement aptamer) and the read-out conductance as well. The preliminary experimental results indicated that human α-thrombin was successfully detected by the corresponding aptamer modified nanofluidic crystal with the limit of detection of 5 nM (0.18 μg/ml) and the read-out signal was enhanced up to 3 folds by using another thrombin aptamer. Being easy to graft probe, facile and low-cost to prepare the nano-device, and having an electrical read-out, the present nanofluidic crystal scheme is a promising and universal strategy for protein sensing.
authors.affiliation: Institute of Microelectronics, Peking University, Beijing, 100871, China ; School of Basic Medical Sciences, Peking University, Beijing, 100871, China.
authors.forename: Jianming
authors.initials: J
authors.lastname: Sang
authors.affiliation: Institute of Microelectronics, Peking University, Beijing, 100871, China.
authors.forename: Hongtan
authors.initials: H
authors.lastname: Du
authors.affiliation: Institute of Microelectronics, Peking University, Beijing, 100871, China ; National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Beijing, 100871, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: School of Basic Medical Sciences, Peking University, Beijing, 100871, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Chu
authors.affiliation: School of Basic Medical Sciences, Peking University, Beijing, 100871, China.
authors.forename: Yuedan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Peking University First Hospital, Peking University, Beijing, 100034, China.
authors.forename: Haichao
authors.initials: H
authors.lastname: Li
authors.affiliation: Institute of Microelectronics, Peking University, Beijing, 100871, China ; National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Beijing, 100871, China.
authors.forename: Haixia
authors.initials: H
authors.lastname: Alice Zhang
authors.affiliation: Institute of Microelectronics, Peking University, Beijing, 100871, China ; National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Beijing, 100871, China.
authors.forename: Wengang
authors.initials: W
authors.lastname: Wu
authors.affiliation: Institute of Microelectronics, Peking University, Beijing, 100871, China ; National Key Laboratory of Science and Technology on Micro/Nano Fabrication, Beijing, 100871, China.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Li