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A Nanoparticle-based Sensor Platform for Cell Tracking and Status/Function Assessment.

Yeo D, Wiraja C, Chuah YJ, Gao Y, Xu C - Sci Rep (2015)

Bottom Line: Upon intracellular entry, nanosensors reside within the cell cytoplasm, serving as a depot to continuously release sensor molecules for up to 30 days.When the biomarker(s) is expressed, a detectable signal is generated (On).As a proof-of-concept, three nanosensor formulations were synthesized to monitor cell viability, secretion of nitric oxide, and β-actin mRNA expression.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical &Biomedical Engineering, Nanyang Technological University, Singapore.

ABSTRACT
Nanoparticles are increasingly popular choices for labeling and tracking cells in biomedical applications such as cell therapy. However, all current types of nanoparticles fail to provide real-time, noninvasive monitoring of cell status and functions while often generating false positive signals. Herein, a nanosensor platform to track the real-time expression of specific biomarkers that correlate with cell status and functions is reported. Nanosensors are synthesized by encapsulating various sensor molecules within biodegradable polymeric nanoparticles. Upon intracellular entry, nanosensors reside within the cell cytoplasm, serving as a depot to continuously release sensor molecules for up to 30 days. In the absence of the target biomarkers, the released sensor molecules remain 'Off'. When the biomarker(s) is expressed, a detectable signal is generated (On). As a proof-of-concept, three nanosensor formulations were synthesized to monitor cell viability, secretion of nitric oxide, and β-actin mRNA expression.

No MeSH data available.


Related in: MedlinePlus

β-actin mRNA nanosensors for imaging β-actin mRNA in MSCs.(A) Sustained release of MBs from β-actin mRNA nanosensors over a 35 day period. (B) β-actin mRNA binding assay for supernatants in (A). (C) Confocal image of β-actin mRNA nanosensor labeled MSCs 4 hours post labeling. Blue is from stained cytoplasm membrane and green represents nanosensor signal. Scale bar represents 20 μm. (D) Fluorescence and phase contrast images of MSCs at 4 hours and 96 hours after being labeled with SLO-MBs or nanosensors. Scale bars represent 100 μm. (E) Normalized fluorescence intensity per cell in D *p < 0.05, n ≥ 150 cells. Values are mean ± SD, N ≥ 3.
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f6: β-actin mRNA nanosensors for imaging β-actin mRNA in MSCs.(A) Sustained release of MBs from β-actin mRNA nanosensors over a 35 day period. (B) β-actin mRNA binding assay for supernatants in (A). (C) Confocal image of β-actin mRNA nanosensor labeled MSCs 4 hours post labeling. Blue is from stained cytoplasm membrane and green represents nanosensor signal. Scale bar represents 20 μm. (D) Fluorescence and phase contrast images of MSCs at 4 hours and 96 hours after being labeled with SLO-MBs or nanosensors. Scale bars represent 100 μm. (E) Normalized fluorescence intensity per cell in D *p < 0.05, n ≥ 150 cells. Values are mean ± SD, N ≥ 3.

Mentions: To examine the reproducibility of nanosensor fabrication, 5 batches of nanosensor formulations containing β-actin & Scrambled MBs were independently fabricated. As a measure of process quality, encapsulation efficiency was quantified using UV-VIS to detect unencapsulated MBs. This was found to have little variation between batches with an average of 82.0 ± 0.06% encapsulation efficiency (Supplementary Fig. S7b). Sustained release of MBs from nanosensors was examined in aqueous solution by quantifying the total eluted quantity. Over a 35 day period, a cumulative release of ~75% of encapsulated MBs was observed (Fig. 6a). The addition of a complementary oligonucleotide—matching the β-actin mRNA sequence into the supernatant resulted in >8-fold increase in fluorescence signal (Fig. 6b), demonstrating the preservation of MB functionality following particle encapsulation and subsequent release.


A Nanoparticle-based Sensor Platform for Cell Tracking and Status/Function Assessment.

Yeo D, Wiraja C, Chuah YJ, Gao Y, Xu C - Sci Rep (2015)

β-actin mRNA nanosensors for imaging β-actin mRNA in MSCs.(A) Sustained release of MBs from β-actin mRNA nanosensors over a 35 day period. (B) β-actin mRNA binding assay for supernatants in (A). (C) Confocal image of β-actin mRNA nanosensor labeled MSCs 4 hours post labeling. Blue is from stained cytoplasm membrane and green represents nanosensor signal. Scale bar represents 20 μm. (D) Fluorescence and phase contrast images of MSCs at 4 hours and 96 hours after being labeled with SLO-MBs or nanosensors. Scale bars represent 100 μm. (E) Normalized fluorescence intensity per cell in D *p < 0.05, n ≥ 150 cells. Values are mean ± SD, N ≥ 3.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4593999&req=5

f6: β-actin mRNA nanosensors for imaging β-actin mRNA in MSCs.(A) Sustained release of MBs from β-actin mRNA nanosensors over a 35 day period. (B) β-actin mRNA binding assay for supernatants in (A). (C) Confocal image of β-actin mRNA nanosensor labeled MSCs 4 hours post labeling. Blue is from stained cytoplasm membrane and green represents nanosensor signal. Scale bar represents 20 μm. (D) Fluorescence and phase contrast images of MSCs at 4 hours and 96 hours after being labeled with SLO-MBs or nanosensors. Scale bars represent 100 μm. (E) Normalized fluorescence intensity per cell in D *p < 0.05, n ≥ 150 cells. Values are mean ± SD, N ≥ 3.
Mentions: To examine the reproducibility of nanosensor fabrication, 5 batches of nanosensor formulations containing β-actin & Scrambled MBs were independently fabricated. As a measure of process quality, encapsulation efficiency was quantified using UV-VIS to detect unencapsulated MBs. This was found to have little variation between batches with an average of 82.0 ± 0.06% encapsulation efficiency (Supplementary Fig. S7b). Sustained release of MBs from nanosensors was examined in aqueous solution by quantifying the total eluted quantity. Over a 35 day period, a cumulative release of ~75% of encapsulated MBs was observed (Fig. 6a). The addition of a complementary oligonucleotide—matching the β-actin mRNA sequence into the supernatant resulted in >8-fold increase in fluorescence signal (Fig. 6b), demonstrating the preservation of MB functionality following particle encapsulation and subsequent release.

Bottom Line: Upon intracellular entry, nanosensors reside within the cell cytoplasm, serving as a depot to continuously release sensor molecules for up to 30 days.When the biomarker(s) is expressed, a detectable signal is generated (On).As a proof-of-concept, three nanosensor formulations were synthesized to monitor cell viability, secretion of nitric oxide, and β-actin mRNA expression.

View Article: PubMed Central - PubMed

Affiliation: School of Chemical &Biomedical Engineering, Nanyang Technological University, Singapore.

ABSTRACT
Nanoparticles are increasingly popular choices for labeling and tracking cells in biomedical applications such as cell therapy. However, all current types of nanoparticles fail to provide real-time, noninvasive monitoring of cell status and functions while often generating false positive signals. Herein, a nanosensor platform to track the real-time expression of specific biomarkers that correlate with cell status and functions is reported. Nanosensors are synthesized by encapsulating various sensor molecules within biodegradable polymeric nanoparticles. Upon intracellular entry, nanosensors reside within the cell cytoplasm, serving as a depot to continuously release sensor molecules for up to 30 days. In the absence of the target biomarkers, the released sensor molecules remain 'Off'. When the biomarker(s) is expressed, a detectable signal is generated (On). As a proof-of-concept, three nanosensor formulations were synthesized to monitor cell viability, secretion of nitric oxide, and β-actin mRNA expression.

No MeSH data available.


Related in: MedlinePlus