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Application of Nanodevices in Sensing and Regenerative Medicine
Published in Gilson Khang, Handbook of Intelligent Scaffolds for Tissue Engineering and Regenerative Medicine, 2017
Rafiq Ahmad, Nirmalya Tripathy, Yoon-Bong Hahn
DNA and RNA can be used to construct artificial nanodevices with strong potential for future biomedical applications. DNA nanodevices can function as biosensors, which detect and report the presence of proteins and naturally occurring nucleic acids, such as mRNA or microRNAs. Complex sensors can be realized by supporting DNA devices with DNA-based information processing. Artificial DNA-based reaction networks can be created that amplify molecular signals or evaluate logical functions to report the simultaneous presence of several disease-related molecules. Other applications for DNA nanodevices are found in controlled release and drug delivery. DNA can be used to build nanocontainers for drugs or switchable hydrogels, which can trap and release compounds. For in vivo applications of DNA nanodevices, techniques for efficient packaging and delivery have been developed and the first examples of intracellular RNA-based nanodevices have already been demonstrated, which uses concepts related to riboswitches and RNAi. Implementation of novel functions into living organisms using such RNA switchable structures and devices are compatible with current developments in synthetic biology.
Approaching Cancer Therapy with Ruthenium Complexes by Their Interaction with DNA
Published in Ajay Kumar Mishra, Lallan Mishra, Ruthenium Chemistry, 2018
The double-stranded double-helical structure of DNA, elucidated by Watson and Crick, is one of the scientific icons of the 20th century (Watson and Crick, 1953). The DNA structure termed B-DNA has two anionic sugar phosphate backbones enfolded around each other in a right-handed double-helix, with the bases hydrogen-bonded together in pairs (A with T and G with C) in the heart of the helix. The hydrophilic sugar-phosphate units point out into solution while the more hydrophobic bases are in the core. The bases are perpendicular to the helical axis and are stacked in a parallel fashion upon each other (face–face, π–π interactions) with a regular inter-planar separation of 3.5A° as shown in Fig. 8.3.
Recent applications of fluorescent nanodiamonds containing nitrogen-vacancy centers in biosensing
Published in Functional Diamond, 2022
Yuchen Feng, Qi Zhao, Yuxi Shi, Guanyue Gao, Jinfang Zhi
Under the background of COVID-19 pandemic in 2019, effective and rapid diagnosis and detection of emerging new virus has become an urgent need. Li et al. [84] proposed a quantum sensor for detecting COVID-19 based on FND with NV center (Figure 11(A, B)). Previous studies have proved that attached Gd3+ can increase the magnetic noise strength felt by NV spins and quench their T1 time. In this theoretical model, the surface of FND was modified by a cationic polymer to adsorb the DNA strand (c-DNA) complementary to the viral RNA, followed by binding Gd3+ complexes (DOTA-Gd3+). In the presence of viral RNA, the c-DNA-DOTA-Gd3+ pair could be separated from the FND surface due to the hybridization of c-DNA and viral RNA. This process is shown in Figure 11(C). The detachment of Gd3+ could result in a large change in the NV photoluminescence yield, thus the detection of virus was realized. Theoretical simulation results showed that the detection limit was as low as hundreds of viral RNA copies. The false negative rate (FNR) reached below 1%, which is far lower than the most advanced RT-PCR diagnostic method. In addition, the technology can be further promoted to diagnose other RNA viruses (like MERS) by using surface c-DNA specific to the target virus.
Reactivity towards DNA and protein, cellular uptake, cytotoxic activity of a mononuclear copper(II) complex of the thioflavin-T (ThT)-based derivative
Published in Journal of Coordination Chemistry, 2020
Zhanfen Chen, Yixuan Wu, Wangxi Wu, Yumin Zhang
The conformational change of CT-DNA due to the interaction with 1 was measured using circular dichroism (CD). The normal CT-DNA has a right-handed chiral conformation and exists in B-form in solution. The observed CD spectrum of CT-DNA (Figure 5) consists of a positive absorption band at 275 nm due to the base stacking and a negative band at 245 nm due to the right-handed helicity and is characteristic of canonical B-form DNA [32]. Z-form DNA is another major nucleic acid duplex structure, which is a left-handed helix. The structure is generally adopted by oligonucleotides that have sequences of alternating pyrimidines and purines in the presence of high salt concentrations [33]. The CD spectra of Z-DNA are generally characterized by a broad negative band at around 290 nm and a positive band centered at 260–265 nm [34]. Herein, when treated with 1, a visible decrease in the ellipticity and slight red-shift were observed on both the positive and negative bands with an increase in the [1]/[CT-DNA] ratio. Such a changing tendency is an indication of B→Z DNA conformation conversion [34, 35]. However, the conversion remained incomplete and B-DNA still prevailed in solution because the inversion of the CD spectra was not observed in the tested conditions. The results suggest that 1 can indeed alter the tertiary structure of DNA.
A new macrocyclic heterobinuclear Cu(II)-Zn(II) complex: synthesis, crystal structure, phosphate hydrolysis, and DNA binding studies
Published in Journal of Coordination Chemistry, 2019
Huizhi Kou, Yang Wang, Peipei Ding, Jianfen Li, Baoxian Shi
Circular dichroism (CD) is a very useful technique to monitor the DNA-morphology changes, which is sensitive to small variations in the chiral conformation of DNA. The CD spectrum of CT-DNA exhibits a positive band at 275 nm due to base stacking and a negative band at 245 nm because of right-handed helicity of DNA [35]. The CD spectra of CT-DNA in the absence and presence of the ligand and complex are given in Figure 8. It is observed from Figure 8 that the positive CD band signal increased with addition of the ligand and complex to CT-DNA. The increased extent of the complex is higher than that of the ligand. The changes in the CD spectra in the presence of the complex indicated that the CT-DNA was unwinded after the intercalation binding with the base pairs of DNA and induced conformational changes from B-DNA to Z-DNA [32].