Label-free, in situ SERS monitoring of individual DNA hybridization in microfluidics

Nanoscale ◽  
2014 ◽  
Vol 6 (15) ◽  
pp. 8521-8526 ◽  
Author(s):  
Ji Qi ◽  
Jianbo Zeng ◽  
Fusheng Zhao ◽  
Steven Hsesheng Lin ◽  
Balakrishnan Raja ◽  
...  
Keyword(s):  
Dna Hybridization ◽  
Label Free

We present label-free,in situmonitoring of individual DNA hybridization in microfluidics.

In-situ ultrasensitive label-free DNA hybridization detection using optical fiber specklegram

2018 ◽  
Vol 272 ◽  
pp. 160-165 ◽  
Author(s):  
Fu Feng ◽  
Wang Chen ◽  
Dihan Chen ◽  
Wei Lin ◽  
Shih-Chi Chen
Keyword(s):  
Optical Fiber ◽  
Dna Hybridization ◽  
Label Free ◽  
Free Dna ◽  
Hybridization Detection

Label-Free Electrochemical Detection of DNA Hybridization Related to Anthrax Lethal Factor by using Carbon Nanotube Modified Sensors

2019 ◽  
Vol 15 (4) ◽  
pp. 502-510 ◽  
Author(s):  
Hakan Karadeniz ◽  
Arzum Erdem
Keyword(s):  
Detection Limit ◽  
Dna Hybridization ◽  
Lethal Factor ◽  
Modified Electrodes ◽  
Label Free ◽  
Carbon Paste ◽  
Chip Technology ◽  
Anthrax Lethal Factor ◽  
Hybridization Time ◽  
Electrochemical Monitoring

Background: Anthrax Lethal Factor (ANT) is the dominant virulence factor produced by B. anthracis and is the major cause of death of infected animals. In this paper, pencil graphite electrodes GE were modified with single-walled and multi-walled carbon nanotubes (CNTs) for the detection of hybridization related to the ANT DNA for the first time in the literature. Methods: The electrochemical monitoring of label-free DNA hybridization related to ANT DNA was explored using both SCNT and MCNT modified PGEs with differential pulse voltammetry (DPV). The performance characteristics of ANT-DNA hybridization on disposable GEs were explored by measuring the guanine signal in terms of optimum analytical conditions; the concentration of SCNT and MCNT, the concentrations of probe and target, and also the hybridization time. Under the optimum conditions, the selectivity of probe modified electrodes was tested and the detection limit was calculated. Results: The selectivity of ANT probes immobilized onto MCNT-GEs was tested in the presence of hybridization of probe with NC no response was observed and with MM, smaller responses were observed in comparison to full-match DNA hybridization case. Even though there are unwanted substituents in the mixture samples containing both the target and NC in the ratio 1:1 and both the target and MM in the ratio 1:1, it has been found that ANT probe immobilized CNT modified graphite sensor can also select its target by resulting with 20.9% decreased response in comparison to the one measured in the case of full-match DNA hybridization case Therefore, it was concluded that the detection of direct DNA hybridization was performed by using MCNT-GEs with an acceptable selectivity. Conclusion: Disposable SCNT/MCNT modified GEs bring some important advantages to our assay including easy use, cost-effectiveness and giving a response in a shorter time compared to unmodified PGE, carbon paste electrode and glassy carbon electrode developed for electrochemical monitoring of DNA hybridization. Consequently, the detection of DNA hybridization related to the ANT DNA by MCNT modified sensors was performed by using lower CNT, probe and target concentrations, in a shorter hybridization time and resulting in a lower detection limit according to the SCNT modified sensors. In conclusion, MCNT modified sensors can yield the possibilities leading to the development of nucleic acid sensors platforms for the improvement of fast and cost-effective detection systems with respect to DNA chip technology.

A new method for the in situ assay of α-glucosidase activity and inhibitor screening through an enzyme substrate-mediated DNA hybridization chain reaction

2019 ◽  
Vol 43 (24) ◽  
pp. 9458-9465
Author(s):  
Xiquan Yue ◽  
Lihong Su ◽  
Xu Chen ◽  
Junfeng Liu ◽  
Longpo Zheng ◽  
...  
Keyword(s):  
Small Molecule ◽  
Dna Hybridization ◽  
New Method ◽  
Hybridization Chain Reaction ◽  
Chain Reaction ◽  
Inhibitor Screening ◽  
Glucosidase Activity ◽  
Enzyme Substrate ◽  
In Situ Assay

The strategy is based on small molecule-mediated hybridization chain reaction.

scholarly journals Multi-pronged approach to human mesenchymal stromal cells senescence quantification with a focus on label-free methods

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Weichao Zhai ◽  
Jerome Tan ◽  
Tobias Russell ◽  
Sixun Chen ◽  
Dennis McGonagle ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Mesenchymal Stromal Cells ◽  
Stromal Cells ◽  
Preclinical Model ◽  
Label Free ◽  
Current Standard ◽  
Differentiation Potential ◽  
Human Mesenchymal Stromal Cells ◽  
Endogenous Fluorophores

AbstractHuman mesenchymal stromal cells (hMSCs) have demonstrated, in various preclinical settings, consistent ability in promoting tissue healing and improving outcomes in animal disease models. However, translation from the preclinical model into clinical practice has proven to be considerably more difficult. One key challenge being the inability to perform in situ assessment of the hMSCs in continuous culture, where the accumulation of the senescent cells impairs the culture’s viability, differentiation potential and ultimately leads to reduced therapeutic efficacies. Histochemical $$\upbeta $$ β -galactosidase staining is the current standard for measuring hMSC senescence, but this method is destructive and not label-free. In this study, we have investigated alternatives in quantification of hMSCs senescence, which included flow cytometry methods that are based on a combination of cell size measurements and fluorescence detection of SA-$$\upbeta $$ β -galactosidase activity using the fluorogenic substrate, C$${_{12}}$$ 12 FDG; and autofluorescence methods that measure fluorescence output from endogenous fluorophores including lipopigments. For identification of senescent cells in the hMSC batches produced, the non-destructive and label-free methods could be a better way forward as they involve minimum manipulations of the cells of interest, increasing the final output of the therapeutic-grade hMSC cultures. In this work, we have grown hMSC cultures over a period of 7 months and compared early and senescent hMSC passages using the advanced flow cytometry and autofluorescence methods, which were benchmarked with the current standard in $$\upbeta $$ β -galactosidase staining. Both the advanced methods demonstrated statistically significant values, (r = 0.76, p $$\le $$ ≤ 0.001 for the fluorogenic C$${_{12}}$$ 12 FDG method, and r = 0.72, p $$\le $$ ≤ 0.05 for the forward scatter method), and good fold difference ranges (1.120–4.436 for total autofluorescence mean and 1.082–6.362 for lipopigment autofluorescence mean) between early and senescent passage hMSCs. Our autofluroescence imaging and spectra decomposition platform offers additional benefit in label-free characterisation of senescent hMSC cells and could be further developed for adoption for future in situ cellular senescence evaluation by the cell manufacturers.

scholarly journals Label-Free and Quantitative Dry Mass Monitoring for Single Cells during In Situ Culture

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1635
Author(s):  
Ya Su ◽  
Rongxin Fu ◽  
Wenli Du ◽  
Han Yang ◽  
Li Ma ◽  
...  
Keyword(s):  
Cell Growth ◽  
Single Cell ◽  
Hela Cells ◽  
Quantitative Measurement ◽  
Single Cells ◽  
Dry Mass ◽  
Quantitative Detection ◽  
Label Free ◽  
Mass Sensitivity

Quantitative measurement of single cells can provide in-depth information about cell morphology and metabolism. However, current live-cell imaging techniques have a lack of quantitative detection ability. Herein, we proposed a label-free and quantitative multichannel wide-field interferometric imaging (MWII) technique with femtogram dry mass sensitivity to monitor single-cell metabolism long-term in situ culture. We demonstrated that MWII could reveal the intrinsic status of cells despite fluctuating culture conditions with 3.48 nm optical path difference sensitivity, 0.97 fg dry mass sensitivity and 2.4% average maximum relative change (maximum change/average) in dry mass. Utilizing the MWII system, different intrinsic cell growth characteristics of dry mass between HeLa cells and Human Cervical Epithelial Cells (HCerEpiC) were studied. The dry mass of HeLa cells consistently increased before the M phase, whereas that of HCerEpiC increased and then decreased. The maximum growth rate of HeLa cells was 11.7% higher than that of HCerEpiC. Furthermore, HeLa cells were treated with Gemcitabine to reveal the relationship between single-cell heterogeneity and chemotherapeutic efficacy. The results show that cells with higher nuclear dry mass and nuclear density standard deviations were more likely to survive the chemotherapy. In conclusion, MWII was presented as a technique for single-cell dry mass quantitative measurement, which had significant potential applications for cell growth dynamics research, cell subtype analysis, cell health characterization, medication guidance and adjuvant drug development.

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