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Stimuli-responsive controlled-release system using quadruplex DNA-capped silica nanocontainers.

Chen C, Pu F, Huang Z, Liu Z, Ren J, Qu X - Nucleic Acids Res. (2010)

Bottom Line: Start from simple conformation changes, the i-motif DNA cap can open and close the pore system in smart response to pH stimulus.A pH-switchable nanoreactor has also been developed to validate the potential of our system for on-demand molecular transport.This proof of concept might open the door to a new generation of carrier materials and could also provide a general route to use other functional nucleic acids/peptide nucleic acids as capping agents in the fields of versatile controlled delivery nanodevices.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Chemical Biology and State Key laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, PR China.

ABSTRACT
A novel proton-fueled molecular gate-like delivery system has been constructed for controlled cargo release using i-motif quadruplex DNA as caps onto pore outlets of mesoporous silica nanoparticles. Start from simple conformation changes, the i-motif DNA cap can open and close the pore system in smart response to pH stimulus. Importantly, the opening/closing and delivery protocol is highly reversible and a partial cargo delivery can be easily controlled at will. A pH-switchable nanoreactor has also been developed to validate the potential of our system for on-demand molecular transport. This proof of concept might open the door to a new generation of carrier materials and could also provide a general route to use other functional nucleic acids/peptide nucleic acids as capping agents in the fields of versatile controlled delivery nanodevices.

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(A) Illustration of the pH-switchable nanoreactor. (B) Fluorescence response of the nanoreactor activity in acidic and neutral environment: (a) MSN-DNA, (b) MSN-CPM before the addition of thiol, (c–g) MSN-CPM after the reaction of thiol from pH 5.0 to 7.0 with increments of 0.5 pH units. (C) Fluorescence images of the nanoreactors in the absence and presence of thiol. Only weak fluorescence could be observed with the addition of thiol at pH 5.0, whereas the container showed strong blue fluorescence at pH 8.0.
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Figure 5: (A) Illustration of the pH-switchable nanoreactor. (B) Fluorescence response of the nanoreactor activity in acidic and neutral environment: (a) MSN-DNA, (b) MSN-CPM before the addition of thiol, (c–g) MSN-CPM after the reaction of thiol from pH 5.0 to 7.0 with increments of 0.5 pH units. (C) Fluorescence images of the nanoreactors in the absence and presence of thiol. Only weak fluorescence could be observed with the addition of thiol at pH 5.0, whereas the container showed strong blue fluorescence at pH 8.0.

Mentions: To realize the potential application of our system as pH-switchable nanoreactor with on-demand sensor-effector functionality, we took advantage of the large load capacity of mesoporous nanoparticles as the supporting matrix to incorporate hydrophobic molecules for chemical reactions in aqueous solution. A water-insoluble non-fluorescent probe 7-Diethylamino-3-(4-maleimidophenyl)-4-methylcoumarin (CPM) was first loaded in the DNA-capped mesoporous nanocontainer, and showed negligible release in solution once it was encapsulated owing to its poor solubibity. Only low molecular weight thiols were expected to diffuse into the pores due to the size-sieving ability of the mesoporous silica framework, and then react with CPM to give rise to highly fluorescent products as depicted in Figure 5A and Supplementary Figure S7. The nanoparticle showed significant blue luminescence at neutral conditions, while only faint fluorescence was found at acidic pH. Meanwhile, it is evident that the fluorescent signal intensity increased with enhanced pH value, which suggests that the gated system was able to change its state of activity by pH variation of the surrounding solution (Figure 5B and C). It was also found that thiol derivative of CPM, CPM-loaded MSN-cDNA and nanocontainers without DNA capping showed ignorable difference at acidic and basic conditions (Supplementary Figures S8–S10), indicating that the behavior of the nanoreactor depends on the conformational change of i-motif DNA on the mesoporous silica surface. Besides the application as nanoscale reactor, the specific recognition of CPM with thiol and unique pH-dependant conformational change of i-motif make it possible to immobilize the CPM-loaded nanocontainer on the solid support as a chip for sensing thiol or pH.Figure 5.


Stimuli-responsive controlled-release system using quadruplex DNA-capped silica nanocontainers.

Chen C, Pu F, Huang Z, Liu Z, Ren J, Qu X - Nucleic Acids Res. (2010)

(A) Illustration of the pH-switchable nanoreactor. (B) Fluorescence response of the nanoreactor activity in acidic and neutral environment: (a) MSN-DNA, (b) MSN-CPM before the addition of thiol, (c–g) MSN-CPM after the reaction of thiol from pH 5.0 to 7.0 with increments of 0.5 pH units. (C) Fluorescence images of the nanoreactors in the absence and presence of thiol. Only weak fluorescence could be observed with the addition of thiol at pH 5.0, whereas the container showed strong blue fluorescence at pH 8.0.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3045591&req=5

Figure 5: (A) Illustration of the pH-switchable nanoreactor. (B) Fluorescence response of the nanoreactor activity in acidic and neutral environment: (a) MSN-DNA, (b) MSN-CPM before the addition of thiol, (c–g) MSN-CPM after the reaction of thiol from pH 5.0 to 7.0 with increments of 0.5 pH units. (C) Fluorescence images of the nanoreactors in the absence and presence of thiol. Only weak fluorescence could be observed with the addition of thiol at pH 5.0, whereas the container showed strong blue fluorescence at pH 8.0.
Mentions: To realize the potential application of our system as pH-switchable nanoreactor with on-demand sensor-effector functionality, we took advantage of the large load capacity of mesoporous nanoparticles as the supporting matrix to incorporate hydrophobic molecules for chemical reactions in aqueous solution. A water-insoluble non-fluorescent probe 7-Diethylamino-3-(4-maleimidophenyl)-4-methylcoumarin (CPM) was first loaded in the DNA-capped mesoporous nanocontainer, and showed negligible release in solution once it was encapsulated owing to its poor solubibity. Only low molecular weight thiols were expected to diffuse into the pores due to the size-sieving ability of the mesoporous silica framework, and then react with CPM to give rise to highly fluorescent products as depicted in Figure 5A and Supplementary Figure S7. The nanoparticle showed significant blue luminescence at neutral conditions, while only faint fluorescence was found at acidic pH. Meanwhile, it is evident that the fluorescent signal intensity increased with enhanced pH value, which suggests that the gated system was able to change its state of activity by pH variation of the surrounding solution (Figure 5B and C). It was also found that thiol derivative of CPM, CPM-loaded MSN-cDNA and nanocontainers without DNA capping showed ignorable difference at acidic and basic conditions (Supplementary Figures S8–S10), indicating that the behavior of the nanoreactor depends on the conformational change of i-motif DNA on the mesoporous silica surface. Besides the application as nanoscale reactor, the specific recognition of CPM with thiol and unique pH-dependant conformational change of i-motif make it possible to immobilize the CPM-loaded nanocontainer on the solid support as a chip for sensing thiol or pH.Figure 5.

Bottom Line: Start from simple conformation changes, the i-motif DNA cap can open and close the pore system in smart response to pH stimulus.A pH-switchable nanoreactor has also been developed to validate the potential of our system for on-demand molecular transport.This proof of concept might open the door to a new generation of carrier materials and could also provide a general route to use other functional nucleic acids/peptide nucleic acids as capping agents in the fields of versatile controlled delivery nanodevices.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Chemical Biology and State Key laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022, PR China.

ABSTRACT
A novel proton-fueled molecular gate-like delivery system has been constructed for controlled cargo release using i-motif quadruplex DNA as caps onto pore outlets of mesoporous silica nanoparticles. Start from simple conformation changes, the i-motif DNA cap can open and close the pore system in smart response to pH stimulus. Importantly, the opening/closing and delivery protocol is highly reversible and a partial cargo delivery can be easily controlled at will. A pH-switchable nanoreactor has also been developed to validate the potential of our system for on-demand molecular transport. This proof of concept might open the door to a new generation of carrier materials and could also provide a general route to use other functional nucleic acids/peptide nucleic acids as capping agents in the fields of versatile controlled delivery nanodevices.

Show MeSH
Related in: MedlinePlus