Label-free Sensor Array Research Articles

A Label-Free Sensor Array Based on Carbon Quantum Dots for Detection of α-Synuclein Oligomers in Saliva.

Salivary oligomeric α-synuclein (α-Syn) has been introduced as a promising biomarker for the diagnosis of Parkinson's disease. Herein, a fluorescence sensor array based on three carbon quantum dots (CQDs) with different surface functional groups was developed for the identification and quantification of salivary α-Syn oligomers. Each of the CQDs generated a different fluorescence response to the target analyte, and the responses were analyzed by NPLS-DA to create a unique response pattern for the target analyte. The developed three-element sensor array showed a linear response to α-Syn oligomers in the range of 0.5-32 μg/mL and a detection limit (LOD) of 0.5 μg/mL, with a cross-validation accuracy of 92% in aqueous solution. The sensor array could detect the analyte in a mixture of different proteins and in the complex medium of saliva, with the LOD of 0.3 μg/mL indicating the massive potential of CQD arrays for developing sensitive, simple, inexpensive, and label-free sensing platforms.

Portable and Label-Free Sensor Array for Discriminating Multiple Analytes via a Handheld Gas Pressure Meter.

Cross-reactive sensor arrays are useful for discriminating multiple analytes in a complex sample. Herein, a portable and label-free gas pressure sensor array was proposed for multiplex analysis via a handheld gas pressure meter. It is based on the interaction diversity of analytes with catalase-like nanomaterials, including Pt nanoparticles (PtNP), Co3O4 nanosheets (Co3O4NS), and Pt-Co alloy nanosheets (PtCoNS), respectively. Thus, the diverse influence of analytes on the catalase-like activity could be output as the difference in the gas pressure. By using principal component analysis, eight proteins were well distinguished by the gas pressure sensor array at the 10 nM level within 12 min. Moreover, different concentrations of proteins and mixtures of proteins could likewise be discriminated. More importantly, the effective discrimination of proteins in human serum and discrimination of five kinds of cells further confirmed the potential of the gas pressure sensor array. Therefore, it provides a portable, cheap, sensitive, and label-free gas pressure sensor array, which is totally different from the reported sensor arrays and holds great potential for portable and cheap discrimination of multiple analytes.

Fingerprint-like pattern for recognition of thiols

Biothiols play essential roles in regulating redox balance and their levels in biological systems may aid early diagnosis of disease states. However, finding a rapid and effective method for the simultaneous discrimination of these thiols is always a challenge. Here, we construct a label-free sensor array for the differentiation of various thiols based on DNA/dye/ion ensembles. In this strategy, nine thiols can be efficiently identified by principal component analysis (PCA). Remarkably, the system can determinate chiral compounds (L-Cys and D-Cys) with different concentrations. In addition, the work offers high selectivity for the determination of biothiols in serum samples. The system is simple in design and convenient in operation. Taken together, this DNA-based sensing platform presents a useful thiols discrimination tool with great potential for practical application in biomedical diagnosis.

A DNA-Based Label-Free Artificial Tongue for Pattern Recognition of Metal Ions.

An array-based sensing method offers several advantages for detecting various analytes. DNA molecules as sensor elements have attracted considerable interest owing to their unique properties. Here, a label-free sensor array using DNA and commercially available dyes to differentiate metal ions is reported. Based on the different interactions between dye-bound DNA and metal ions, the fluorescence intensities of the sensor elements are changed to different degrees. In this way, fourteen metal ions can be efficiently distinguished by principal component analysis (PCA) and hierarchical cluster analysis (HCA). A highly sensitive discrimination of metal ions with 92.8 % identification accuracy can be achieved. The present work provides a simple and convenient method for the construction of a DNA-based sensor array.

Rapid label-free detection of E. coli using antimicrobial peptide assisted impedance spectroscopy

A compact, label-free sensor array for rapid detection ofEscherichia coli(E. coli) using antimicrobial peptide assisted impedimetric sensor platform.