A label-free fluorescence biosensor for highly sensitive detection of lectin based on carboxymethyl chitosan-quantum dots and gold nanoparticles.
In this work, we report a novel label-free fluorescence "turn off-on" biosensor for lectin detection. The highly sensitive and selective sensing system is based on the integration of carboxymethyl chitosan (CM-CHIT), CuInS2 quantum dots (QDs) and Au nanoparticles (NPs). Firstly, CuInS2 QDs featuring carboxyl groups were directly synthesized via a hydrothermal synthesis method. Then, the carboxyl groups on the CuInS2 QDs surface were interacted with the amino groups (NH2), carboxyl groups (COOH) and hydroxyl groups (OH) within CM-CHIT polymeric chains via electrostatic interactions and hydrogen bonding to form CM-CHIT-QDs assemblies. Introduction of Au NPs could quench the fluorescence of CM-CHIT-QDs through electron and energy transfer. In the presence of lectin, lectin could bind exclusively with CM-CHIT-QDs by means of specific multivalent carbohydrate-protein interaction. Thus, the electron and energy transfer process between CM-CHIT-QDs and Au NPs was inhibited, and as a result, the fluorescence of CM-CHIT-QDs was effectively "turned on". Under the optimum conditions, there was a good linear relationship between the fluorescence intensity ratio I/I0 (I and I0 were the fluorescence intensity of CM-CHIT-QDs-Au NPs in the presence and absence of lectin, respectively) and lectin concentration in the range of 0.2-192.5 nmol L(-1), And the detection limit could be down to 0.08 nmol L(-1). Furthermore, the proposed biosensor was employed for the determination of lectin in fetal bovine serum samples with satisfactory results.
Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun 130012, PR China.
Ziping
Z
Liu
Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun 130012, PR China.
Hua
H
Liu
Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun 130012, PR China.
Lei
L
Wang
Department of Analytical Chemistry, College of Chemistry, Jilin University, Changchun 130012, PR China. Electronic address: suxg@jlu.edu.cn.
Xingguang
X
Su
D000818:Animals; D015374:Biosensing Techniques / Q000379:methods*; D002417:Cattle; D048271:Chitosan / Q000031:analogs & derivatives* / Q000737:chemistry; D003208:Concanavalin A / Q000032:analysis* / Q000737:chemistry; D004579:Electron Transport; D006046:Gold / Q000737:chemistry*; D006801:Humans; D057230:Limit of Detection; D053768:Metal Nanoparticles / Q000737:chemistry*; D045663:Quantum Dots / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
C514968:carboxymethyl-chitosan; D003208:Concanavalin A; D006046:Gold; D048271:Chitosan
Au NPs; Carbohydrate-protein interactions; CuInS(2) QDs; Fluorescence biosensor; Lectins