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Co-ordinated Split Aptamer Assembly and Disassembly on Gold Nanoparticle for Functional Detection of HIV-1 Tat
摘要: Human immunodeficiency virus (HIV) is a life threatening, weakens the immune system upon infection, thus ultimately resulting in the fatal health issues. This situation necessitates the generation of different strategies for HIV detection. HIV-1 Tat, a transactivator of HIV gene expression, was chosen in this study as the target of a non-functional split aptamer. Implementation of split aptamer has been demonstrated in this work for colorimetric detection of HIV-1 Tat. An unmodified gold nanoparticle (GNP)-based colorimetric assay was used for the visible detection of the proof, displays color transitions from red to purple in relation to the dose-dependency of HIV-1 Tat against the split aptamer in ionic solutions. The visible color transition was characterized using UV-Vis spectrophotometer showing spectrum shift and supported by Scanning Electron Microscopy observation. With addition of sodium chloride, the color of the solution started to change to purple and spectrum started to shift to higher wavelength due to aggregation at HIV-1 Tat concentration as low as 10 nM. Specificity test was conducted with duplexed split aptamer and HIV-1 p24 has shown slight color changes. With HIV-1 Nef, GNP solution retains the color similar to the control, which indicated the specific split aptamer interaction to HIV-1 Tat.
关键词: Colorimetry,HIV-1 Tat,Gold nanoparticle,Split aptamer
更新于2025-09-23 15:19:57
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Split aptamer based sensing platform for adenosine deaminase detection by fluorescence resonance energy transfer
摘要: In this paper, a split aptamer based fluorescence resonance energy transfer (FRET) platform was constructed for the determination of adenosine deaminase (ADA) activity by using gold nanoclusters (AuNCs) and gold nanoparticles (AuNPs). A single adenosine triphosphate (ATP) aptamer was split into two fragments (referred to as P1 and P2). P1 was covalently attached to the AuNCs at the 5′ end (P1-AuNCs), and P2 was labeled with AuNPs at the 3′ end (P2-AuNPs). In the presence of ATP, ATP bound with the two fragments with high affinity to link P1-AuNCs and P2-AuNPs together, thus the fluorescence of P1-AuNCs was quenched via FRET from P1-AuNCs to P2-AuNPs. With the addition of ADA, ATP was transformed into inosine triphosphate (ITP), and then P1 and P2 were released to cause the fluorescence recovery of the system. So a split aptamer based FRET platform for ADA detection can be established via the fluorescence intensity change of the system. This platform showed a good linear relationship between the fluorescence intensity and ADA concentration in the range of 2-120 U L-1, and the limit of detection (LOD) was 0.72 U L-1. Moreover, the detection of ATP in human serum sample demonstrated the accuracy and applicability of the method for ADA detection in real sample.
关键词: Split aptamer,Gold nanoclusters,Adenosine deaminase,Fluorescence,Gold nanoparticles
更新于2025-09-19 17:15:36
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Amplified Split Aptamer Sensor Delivered Using Block Copolymer Nanoparticles for Small Molecule Imaging in Living Cells
摘要: We develop a novel amplified split aptamer sensor for highly sensitive detection and imaging of small molecules in living cells by using cationic block copolymer nanoparticles (BCNs) with entrapped fluorescent conjugated polymer as a delivery agent. The design of split aptamer as the initiator of hybridization chain reaction (HCR) affords the possibility of enhancing the signal-to-background ratio and thus allows high-contrast imaging for small molecules with relatively weak interactions with their aptamers. The novel design of using fluorescent cationic BCNs as the nanocarrier enables efficient and self-tracking transfection of DNA probes. Results reveal that BCNs exhibit high fluorescence brightness allowing direct tracking of the delivery location. The developed amplified split aptamer sensor is shown to have high sensitivity and selectivity for in vitro quantitative detection of ATP with a detection limit of 30 nM. Live cell studies show that the sensor provides a "signal on" approach for specific, high-contrast imaging of ATP. The DNA sensor based HCR system may provide a new generally applicable platform for detection and imaging of low-abundance biomarkers.
关键词: sensor,small molecule imaging,enzyme-free amplification,block copolymer nanoparticles,split aptamer
更新于2025-09-10 09:29:36
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High-performance interactive analysis of split aptamer and HIV-1 Tat on multiwall carbon nanotube-modified field-effect transistor
摘要: Interaction between split RNA aptamer and the clinically important target, HIV-1 Tat was investigated on a biosensing surface transduced by functionally choreographed multiwall carbon nanotubes (MWCNTs). Acid oxidation was performed to functionalize MWCNTs with carboxyl functional groups. X-ray photoelectron spectroscopy analysis had profound ~2.91% increment in overall oxygen group and ~1% increment was noticed with a specific carboxyl content owing to C=O and O–C=O bonding. The interaction between split RNA aptamer and HIV-1 Tat protein was quantified by electrical measurements with the current signal (Ids) over a gate voltage (Vgs). Initially, 34.4 mV gate voltage shift was observed by the immobilization of aptamer on MWCNT. With aptamer and HIV-1 Tat interaction, the current flow was decreased with the concomitant gate voltage shift of 23.5 mV. The attainment of sensitivity with split aptamer and HIV-1 Tat interaction on the fabricated device was 600 pM. To ensure the genuine interaction of aptamer with HIV-1 Tat, other HIV-1 proteins, Nef and p24 were interacted with aptamer and they displayed the negligible interferences with gate voltage shift of 3.5 mV and 5.7 mV, which shows 4 and 2.5 folds lesser than HIV-1 Tat interaction, respectively.
关键词: Field effect transistor,Multiwall carbon nanotube,Split aptamer,HIV-1 Tat
更新于2025-09-09 09:28:46