Deoxyribonucleic Acid Strands Research Articles

Coupling Single Domain Antibodies to Catalytic Hairpin Assemblies for Homogeneous Assays

AbstractImmunoassays are widely used in various fields, including biomedical research, clinical diagnostics, and environmental monitoring. Single domain antibodies (sdAbs) provide small, tailorable, recognition elements that have been integrated into immunoassays for detecting a myriad of targets. Deoxyribonucleic acid (DNA) circuits are synthetic molecular devices composed of DNA strands that can perform logical or computational operations. They have a range of applications, including biosensing, diagnostics, and drug delivery. Recently, an immunoassay method was reported that used catalytic hairpin assemblies (CHA) with antibodies for homogeneous protein detection. The CHA process uses DNA hairpins that interact in the presence of a catalytic DNA sequence. This paper presents a new strategy to couple the recognition of sdAbs with CHA circuits using genetic fusions of sdAbs with rhizavidin (rz), a dimeric biotin binding protein. A pair of sdAb‐rz constructs is each functionalized with a biotinylated DNA sequence that represents half of the catalyst. When both sdAbs bind to the target protein, a signal is generated through the CHA circuit. The split catalyst approach amplifies signals through a DNA circuit without washing steps. Furthermore, this method distinctively utilizes programmable DNA circuits, which are highly modular and can accommodate new targets without disrupting the assay.

Ongoing Phase III Randomized Trial of Salvage DFP-10917 Vs. Non-Intensive Reinduction or Intensive Reinduction for Acute Myelogenous Leukemia (AML)

Background: DFP-10917 is a deoxycytidine analogue with a novel structure. It contains a side chain cyanide (CN) group at the 2 carbon of deoxyribose that induces DNA damage in a manner unique from structurally related nucleoside analogues (eg, cytarabine, decitabine, or gemcitabine). When administered at high doses, DFP-10917 inactivates deoxyribonucleic acid (DNA) polymerase leading to S-phase arrest similar to cytarabine. When administered at low concentrations by continuous infusion, it displays an alternative, potentially advantageous, mechanism of action - DNA strand breakage leading to G2/M phase arrest and ultimately cell apoptosis. The strand breakage occurs via a spontaneous beta elimination reaction that requires no additional enzymatic activity. There is no current standard treatment for patients with relapsed/refractory (R/R) AML. Results of a completed Phase I/II study in R/R AML (D11-11002; NCT01702155) demonstrated preliminary efficacy of DFP-10917 in this indication, with a ~50% complete response (CR) rate in Phase II. Five of 14 patients who achieved CR proceeded to stem cell transplantation. Based on completed studies, risks associated with DFP-10917 are predominantly hematological (eg, neutropenia, anemia, febrile neutropenia, leukopenia, lymphopenia, thrombocytopenia). Study Design and Methods: Based on promising Phase II results, the Sponsor initiated Study D18-11141 (NCT03926624), a Phase III, randomized, controlled study to compare the rate and duration of CR in patients with AML R/R to 2-4 prior induction regimens. Patients receive either DFP-10917 or non-intensive reinduction (low-dose cytarabine [LoDAC], azacitidine, decitabine, venetoclax + LoDAC or azacitidine or decitabine) or intensive reinduction (high and intermediate dose cytarabine regimens). Patients assigned to DFP-10917 receive 6 mg/m 2/day by continuous infusion for 14 days followed by a 14-day rest period. Control treatment is administered per physician's decision. Adults aged ≥18 years with histologically or pathologically confirmed diagnosis of AML based on World Health Organization classification and adequate performance status (≤2) and organ function are eligible. Study Status: The study is ongoing at 34 study centers in the United States. As of July 2023, 162 patients were enrolled, with 82 assigned to DFP-10917. A majority of the patients are male (57.4%) and aged <75 years (83.3%). Overall, 44% have AML with myelodysplasia-related changes; 36% have AML not otherwise specified; and <20% have AML with recurrent genetic abnormalities or therapy-related myeloid neoplasms. Enrollment and management of patients were affected from 2020 to 2021 by COVID-19 restrictions. A prospectively-planned interim analysis will occur after the 150 th patient randomized is followed for >2 months. Based on recruitment projections, this analysis is scheduled for 09/2023. At that time, the Data Safety Monitoring Board will review an unblinded estimate of the treatment effect for the primary endpoint of CR, with the study either stopped for superiority or futility or continuing to a final analysis. If continued, the number of patients required for the final analysis will range from 300 to 450, in increments of 50, with the number determined based on the size of the interim treatment effect for the primary endpoint of CR or the secondary endpoint of overall survival.

Azadirachta indica A. Juss (neem) phenolic extract inhibits human B-lymphoblastoid cells growth via cell cycle arrest, apoptosis induction, and DNA damage

Aim: As far as is known, the pharmaceutical effects of neem on human B-lymphoblastoid (TK6) cells have not been studied until now. Hence, the present study aimed to obtain neem phenolic extracts for inhibits the proliferation of TK6 cells and explore some possible underlying mechanisms involved in these effects. Methods: Hexane extract (HE) was obtained in the first step. After that, the residual hexane was removed from the neem. The dried neem sample was used in a new extraction for obtaining the ethyl acetate extract (EAE). Total phenolic compounds (TPC) and total flavonoid contents (TFC) were determined by spectrophotometric methods. Lactate dehydrogenase (LDH) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) tests were used to evaluate the cytotoxicity in TK6 cells. The stop at G0/G1 cell cycle and inducing apoptosis in the TK6 cells were analyzed by flow cytometry. For deoxyribonucleic acid (DNA) damage evaluation, the alkaline comet test was used. Results: The higher TFC (65.50 mg/g of extract ± 1.17 mg/g of extract) and TPC (52.08 mg of extract ± 0.88 mg of extract) were obtained in EAE compared to HE that was obtained TFC of 14.61 mg/g of extract ± 0.60 mg/g of extract and TPC of 3.20 mg/g of extract ± 1.20 mg/g of extract. EAE was more significantly cytotoxic to TK6 cells than HE. The apoptosis induction was higher after exposure to 15.0 µg/mL of EAE (11.29%) in comparison to 15.0 µg/mL of HE (2.52%). The G0/G1 phase increased from 72% negative control (NC) to 83% after treatment with neem extracts (15 µg/mL). Neem extracts were also able to cause DNA strand breaks in TK6 cells. Conclusions: The extraction residue from neem leaf after hexane extraction is a source important of cytotoxic and genotoxic molecules against TK6 cells, the results also can suggest that the toxic effects in TK6 cells can be provided most likely due to the presence of high content of TPC from neem extracts.

On the Thermal Behavior during Spatial Anisotropic Femtoseconds Laser-DNA Interaction: The Crucial Role of Hermite Polynomials.

A novel analytical formalism based on the quantum heat transport equation is proposed for the interaction of fs-laser pulses with deoxyribonucleic acid (DNA) strands. The formalism has the intensity of the laser beam and the interaction time between the laser and the DNA as input parameters. To this end, the thermal distribution generated in the irradiated DNA strands was introduced by splitting the laser beam into transverse Hermite-Gauss modes. To achieve this goal, a new powerful mathematical model was developed and applied. Fluctuations in laser intensity were taken into account by modeling them as superpositions of Hermite-Gauss laser modes. These analyses were carried out for a laser pulse duration of 100 fs, where a tiny heat-affected zone is expected, with positive predicted effects on the stability and repeatability of this technology. The main conclusion is that the laser beam spatial distribution intensity plays an essential role in the generation of the shape and magnitude of the thermal field at the junction of the irradiated DNA strands. The model may prove useful in modeling laser beam processing under significant intensity fluctuations. There are at least two main areas of application for the present model of heat transfer from laser to DNA: (i) the study of DNA elongation without destroying the target information (for a sample temperature variation lower than 10 K; in the case of H[1,y]); and (ii) cancer treatment (especially of skin tissue), where we should obtain a temperature variation higher than 10 K (but lower than 30 K; in the case of H[2,y], H[4,y]), in order to eradicate the diseased cells.

Performance analysis of DNA crossbar arrays for high-density memory storage applications

Deoxyribonucleic acid (DNA) has emerged as a promising building block for next-generation ultra-high density storage devices. Although DNA has high durability and extremely high density in nature, its potential as the basis of storage devices is currently hindered by limitations such as expensive and complex fabrication processes and time-consuming read–write operations. In this article, we propose the use of a DNA crossbar array architecture for an electrically readable read-only memory (DNA-ROM). While information can be ‘written’ error-free to a DNA-ROM array using appropriate sequence encodings its read accuracy can be affected by several factors such as array size, interconnect resistance, and Fermi energy deviations from HOMO levels of DNA strands employed in the crossbar. We study the impact of array size and interconnect resistance on the bit error rate of a DNA-ROM array through extensive Monte Carlo simulations. We have also analyzed the performance of our proposed DNA crossbar array for an image storage application, as a function of array size and interconnect resistance. While we expect that future advances in bioengineering and materials science will address some of the fabrication challenges associated with DNA crossbar arrays, we believe that the comprehensive body of results we present in this paper establishes the technical viability of DNA crossbar arrays as low power, high-density storage devices. Finally, our analysis of array performance vis-à-vis interconnect resistance should provide valuable insights into aspects of the fabrication process such as proper choice of interconnects necessary for ensuring high read accuracies.

Remote Sensing Image Encryption Using Optimal Key Generation-Based Chaotic Encryption

The Internet of Things (IoT) offers a new era of connectivity, which goes beyond laptops and smart connected devices for connected vehicles, smart homes, smart cities, and connected healthcare. The massive quantity of data gathered from numerous IoT devices poses security and privacy concerns for users. With the increasing use of multimedia in communications, the content security of remote-sensing images attracted much attention in academia and industry. Image encryption is important for securing remote sensing images in the IoT environment. Recently, researchers have introduced plenty of algorithms for encrypting images. This study introduces an Improved Sine Cosine Algorithm with Chaotic Encryption based Remote Sensing Image Encryption (ISCACE-RSI) technique in IoT Environment. The proposed model follows a three-stage process, namely pre-processing, encryption, and optimal key generation. The remote sensing images were preprocessed at the initial stage to enhance the image quality. Next, the ISCACE-RSI technique exploits the double-layer remote sensing image encryption (DLRSIE) algorithm for encrypting the images. The DLRSIE methodology incorporates the design of Chaotic Maps and deoxyribonucleic acid (DNA) Strand Displacement (DNASD) approach. The chaotic map is employed for generating pseudorandom sequences and implementing routine scrambling and diffusion processes on the plaintext images. Then, the study presents three DNASD-related encryption rules based on the variety of DNASD, and those rules are applied for encrypting the images at the DNA sequence level. For an optimal key generation of the DLRSIE technique, the ISCA is applied with an objective function of the maximization of peak signal to noise ratio (PSNR). To examine the performance of the ISCACE-RSI model, a detailed set of simulations were conducted. The comparative study reported the better performance of the ISCACE-RSI model over other existing approaches.

DNA Computing with Water Strider Based Vector Quantization for Data Storage Systems

The exponential growth of data necessitates an effective data storage scheme, which helps to effectively manage the large quantity of data. To accomplish this, Deoxyribonucleic Acid (DNA) digital data storage process can be employed, which encodes and decodes binary data to and from synthesized strands of DNA. Vector quantization (VQ) is a commonly employed scheme for image compression and the optimal codebook generation is an effective process to reach maximum compression efficiency. This article introduces a new DNA Computing with Water Strider Algorithm based Vector Quantization (DNAC-WSAVQ) technique for Data Storage Systems. The proposed DNAC-WSAVQ technique enables encoding data using DNA computing and then compresses it for effective data storage. Besides, the DNAC-WSAVQ model initially performs DNA encoding on the input images to generate a binary encoded form. In addition, a Water Strider algorithm with Linde-Buzo-Gray (WSA-LBG) model is applied for the compression process and thereby storage area can be considerably minimized. In order to generate optimal codebook for LBG, the WSA is applied to it. The performance validation of the DNAC-WSAVQ model is carried out and the results are inspected under several measures. The comparative study highlighted the improved outcomes of the DNAC-WSAVQ model over the existing methods.

In vitro assessment of the severity of deoxyribonucleic acid damage in different types of cataracts directly in lens epithelial cells.

This study aimed to assess the severity of deoxyribonucleic acid (DNA) damage in lens epithelial cells (LECs) of senile cortical, nuclear, and posterior subcapsular cataracts. LECs were obtained from senile cortical, nuclear, and subcapsular types of cataracts after surgery. DNA damage in the cells was immediately assessed quantitatively using the CometScore™ software. Comets were found in cataractous LECs. The formation of "comets" in the DNA of LECs can be visualized using single-cell gel electrophoresis and indicates DNA strand breaks because the damaged DNA migrates at a different rate than the nondamaged DNA. Maximal damage was observed in Grade 3 cortical, nuclear, and subcapsular forms of cataracts. Statistically significant DNA damage was seen between grades 1 and 3 of cortical type of cataract, grades 1 and 3 of nuclear type of cataract, and grades 2 and 3 and grades 1 and 3 of posterior subcapsular type of cataract. In patients with senile cataract, DNA of LECs was randomly damaged, and this type of damage was possibly caused by reactive oxygen species (ROS). Maximum DNA damage was found in patients with Grade 3 senile cortical, nuclear, and subcapsular type cataracts. The pathogenesis of senile cataracts is multifactorial and includes continuous molecular stress resulting from photooxidative stress, UV irradiation, and oxidative reactions.

DNA technology for big data storage and error detection solutions: Hamming code vs Cyclic Redundancy Check (CRC)

There is an increasing need for high-capacity, highdensity storage media that can retain data for a long time, due to the exponential development in the capacity of information generated. The durability and high information density of synthetic deoxyribonucleic acid (DNA) make it an attractive and promising medium for data storage. DNA data storage technology is expected to revolutionize data storage in the coming years, replacing various Big Data storage technologies. As a medium that addresses the need for high-latency, immutable information storage, DNA has several potential advantages. One of the key advantages of DNA storage is its extraordinary density. Theoretically, a gram of DNA can encode 455 exabytes, or 2 bits per nucleotide. Unlike other digital storage media, synthetic DNA enables large quantities of data to be stored in a biological medium. This reduces the need for traditional storage media such as hard disks, which consume energy and require materials such as plastic or metals, and also often leads to the generation of electronic waste when they become obsolete or damaged. Additionally, although DNA degrades over thousands of years under non-ideal conditions, it is generally readable. Furthermore, as DNA possesses natural reading and writing enzymes as part of its biological functions, it is expected to remain the standard for data retrieval in the foreseeable future. However, the high error rate poses a significant challenge for DNA-based information coding strategies. Currently, it is impossible to execute DNA strand synthesis, amplification, or sequencing errors-free. In order to utilize synthetic DNA as a storage medium for digital data, specialized systems and solutions for direct error detection and correction must be implemented. The goal of this paper is to introduce DNA storage technology, outline the benefits and added value of this approach, and present an experiment comparing the effectiveness of two error detection and correction codes (Hamming and CRC) used in the DNA data storage strategy.

Fiber-Based Surface Plasmon Resonance Biosensor for Leptospira DNA Detection

Fiber-based surface plasmon resonance (SPR) sensors are the ideal configuration for rapid and label-free biomolecule detection. Gold-coated tapered optical fiber was used to excite the SPR mode that propagates at the metal–dielectric interface. By forming self-assembled monolayers (SAMs) of active chemical functional groups, the deoxyribonucleic acid (DNA) probe targeting the secY gene of Leptospira was immobilized onto the sensor surface. Red shifts in the SPR wavelengths were observed at different concentrations of leptospiral DNA target against the immobilized DNA probe due to the ability of plasmonic interaction to sensitively detect the binding of biomolecules on the sensor area. The developed sensor showed satisfactory linear responses at two target concentration ranges; low (1.0 fM to 1.0 pM) and high (0.1 nM to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.0~\mu \text{M}$ </tex-math></inline-formula> ), with the highest sensitivity of 1.22 nm per log M. The negative control test also revealed high sensor specificity toward the complementary DNA strand. This sensor will represent a significant step toward laboratory-free diagnosis of leptospirosis.

Mathematical formalism of femtosecond laser-deoxyribonucleic acid interaction: thermal evolution

A novel analytical formalism is proposed based upon Quantum heat transport equation in order to describe the femtoseconds/picoseconds laser pulses interaction with the Deoxyribonucleic acid (DNA). The formalism generates solutions based upon inputs as: voltage, laser beam intensity and laser - DNA interaction time. Thermal waves induced inside irradiated DNA are defined and accounted for. Analytical simulations show that the optimum regime of laser - DNA interaction was reached for a potential carrier generated at the interface equal to 3.5 × 10−3 eV. It has to be mentioned that the formalism breaks down if the potential carrier generated at the interface is inferior to 10−2 eV. Accordingly, for pulse duration inferior to 1 ps, the laser beam spatial-temporal distribution has an essential role in defining the shape and magnitude of the thermal distribution within the irradiated DNA strands.

Model of Streptozotocin-nicotinamide Induced Type 2 Diabetes: a Comparative Review.

The aim of the present study was to review the streptozotocin-nicotinamide (STZ-NA) diabetes model. Type 2 diabetes is more prevalent (90-95%) in adults than type 1. Experimentally- induced diabetes models may be established by chemicals, viral agents, insulin antibodies, surgery, etc. The most advisable and prompt method to induce diabetes is using chemicals, and STZ and alloxan are widely used chemicals. STZ has proven to be a better diabetogenic agent than alloxan because alloxan has many drawbacks, as it induces only type 1 diabetes, has a high mortality rate in rats, and causes ketosis in animals. Moreover, it has lesser selectivity towards β-cells, and the diabetes-induced is reversible. STZ can be used to induce both type 1 and type 2 diabetes. It is noted that the genotoxic behavior of STZ in animals is accomplished through a reduction of nicotinamide adenine dinucleotide (NAD+) in pancreatic β-cells via the GLUT2 (Glucose transporter 2), which can cause cellular damage by DNA (Deoxyribonucleic acid) strand breaks that lead to cell death. NA is a biochemical precursor of NAD+, and it is a poly-ADP-ribose-polymerase-1 (PARP- 1) inhibitor. NAD+ is an important redox reaction co-enzyme for the production of adenosine triphosphate (ATP) and many other metabolic pathways. Extreme DNA damage contributes to the over-activation of PARP-1, loss of cellular resources, and necrotic cells death. Some studies have expressed that NA can protect pancreatic β-cells against the severe cytotoxicity of STZ. The review concluded that the STZ-NA model is dependent on the competency of NA to attain partial protection against the β-cytotoxic essence of STZ to induce type-2 diabetes.

Analysis of double-chain deoxyribonucleic acid dynamical system in pandemic confrontation

Every cell contains deoxyribonucleic acid (DNA), which serves as the fundamental information storage medium, preserving the genetic information required by organisms in order to survive and reproduce themselves. The analytical solution of the (3+1) double chain Deoxyribonucleic acid dynamical model is achieved using the Lie transformation approach. The equation is transformed into an ordinary differential equation (ODE) using three sequential symmetry reductions. Two examples are investigated, the results of which include some solitary wave solutions. The solutions found may be classified into three types: one-soliton, multi-soliton, and periodic wave solutions. Some of the answers that were discovered have been visually explored. The nonlinear dynamics of the system manifests itself in the solitary and anti-solitary waves of the DNA strands, which are both seen. The collected results may be beneficial to evaluate different applications for further scientific conclusions.

DNA Supramolecular Assembly on Micro/Nanointerfaces for Bioanalysis.

Facing increasing demand for precision medicine, materials chemistry systems for bioanalysis with accurate molecular design, controllable structure, and adjustable biological activity are required. As a genetic biomacromolecule, deoxyribonucleic acid (DNA) is created via precise, efficient, and mild processes in life systems and can in turn precisely regulate life activities. From the perspective of materials chemistry, DNA possesses the characteristics of sequence programmability and can be endowed with customized functions by the rational design of sequences. In recent years, DNA has been considered to be a potential biomaterial for analysis and has been applied in the fields of bioseparation, biosensing, and detection imaging. To further improve the precision of bioanalysis, the supramolecular assembly of DNA on micro/nanointerfaces is an effective strategy to concentrate functional DNA modules, and thus the functions of DNA molecules for bioanalysis can be enriched and enhanced. Moreover, the new modes of DNA supramolecular assembly on micro/nanointerfaces enable the integration of DNA with the introduced components, breaking the restriction of limited functions of DNA materials and achieving more precise regulation and manipulation in bioanalysis. In this Account, we summarize our recent work on DNA supramolecular assembly on micro/nanointerfaces for bioanalysis from two main aspects. In the first part, we describe DNA supramolecular assembly on the interfaces of microscale living cells. The synthesis strategy of DNA is based on rolling-circle amplification (RCA), which generates ultralong DNA strands according to circular DNA templates. The templates can be designed with complementary sequences of functional modules such as aptamers, which allow DNA to specifically bind with cellular interfaces and achieve efficient cell separation. In the second part, we describe DNA supramolecular assembly on the interfaces of nanoscale particles. DNA sequences are designed with functional modules such as targeting, drug loading, and gene expression and then are assembled on interfaces of particles including upconversion nanoparticles (UCNPs), gold nanoparticles (AuNPs), and magnetic nanoparticle (MNPs). The integration of DNA with these functional particles achieves cell manipulation, targeted tumor imaging, and cellular regulation. The processes of interfacial assembly are well controlled, and the functions of the obtained bioanalytical materials can be flexibly regulated. We envision that the work on DNA supramolecular assembly on micro/nanointerfaces will be a typical paradigm for the construction of more bioanalytical materials, which we hope will facilitate the development of precision medicine.

Interconnects for DNA, Quantum, In-Memory, and Optical Computing: Insights From a Panel Discussion

The computing world is witnessing a proverbial Cambrian explosion of emerging paradigms propelled by applications, such as artificial intelligence, big data, and cybersecurity. The recent advances in technology to store digital data inside a deoxyribonucleic acid (DNA) strand, manipulate quantum bits (qubits), perform logical operations with photons, and perform computations inside memory systems are ushering in the era of emerging paradigms of DNA computing, quantum computing, optical computing, and in-memory computing. In an orthogonal direction, research on interconnect design using advanced electro-optic, wireless, and microfluidic technologies has shown promising solutions to the architectural limitations of traditional von-Neumann computers. In this article, experts present their comments on the role of interconnects in the emerging computing paradigms, and discuss the potential use of chiplet-based architectures for the heterogeneous integration of such technologies.

Label-free and sensitive microRNA detection method based on the locked nucleic acid assisted fishing amplification strategy.

Herein, a label free and sensitive miRNA detection method with enhanced practical applicability was developed based on the locked nucleic acid (LNA) assisted repeated fishing amplification strategy. The working mechanism of the proposed method is as follows: 1) a DNA probe (i.e, L-DNA) with LNA bases is immobilized onto the surface of a gold foil. The L-DNA hybridizes with the 3' terminus of the first strands of complementary deoxyribonucleic acid (cDNA) of the target miRNA in the test samples; 2) The protruding 5' terminus of the cDNA serves as a 'fishhook' to repeatedly fish the products of a hybridization chain reaction (HCR) out from a 'reaction tube'; 3) The HCR products can be unloaded from the gold foil into a 'product tube' through temperature-controlled dehybridization; 4) The concentration of the target miRNA is determined based on the fluorescence intensity generated by the addition of SYBR-Green I (SG) into the 'product tube'. The proposed platform was applied to the detection of miRNA-122 in cell lysate samples and obtained quantitative results with accuracy comparable to the quantitative reverse transcription PCR method (qRT-PCR). It is worth pointing out that the proposed platform achieved a limit of detection value of 2.9fM for miRNA-122 by a simple but effective LNA-assisted repeated fishing amplification strategy instead of complicated enzyme-based amplification techniques. It is reasonable to expect that the proposed method provides a competitive alternative for designing practically applicable, cost-effective and label-free miRNA detection methods.

A target-initiated autocatalytic 3D DNA nanomachine for high-efficiency amplified detection of MicroRNA.

Considering the challenges of generating simple and efficient DNA (deoxyribonucleic acid) nanomachines for sensitive bioassays and the great potential of target-induced self-cycling catalytic systems, herein, a novel autocatalytic three-dimensional (3D) DNA nanomachine was constructed based on cross-catalytic hairpin assembly on gold nanoparticles (AuNPs) to generate self-powered efficient cyclic amplification. Typically, the DNA hairpins H1, H2, H3 and H4 were immobilized onto AuNPs first. In the presence of target microRNA-203a, the 3D DNA nanomachines were triggered to activate a series of CHA (catalytic hairpin assembly) reactions. Based on the rational design of the system, the products of the CHA 1 reaction were the trigger of the CHA 2 reaction, which could trigger the CHA 1 reaction in turn, generating an efficient self-powered CHA amplification strategy without adding fuel DNA strands or protein enzymes externally and producing high-efficiency fluorescence signal amplification. More importantly, the proposed autocatalytic 3D DNA nanomachines outperformed conventional 3D DNA nanomachines combined with the single-directional cyclic amplification strategy to maximize the amplification efficiency. This strategy not only achieves high-efficiency analysis of microRNAs (microribonucleic acids) in vitro and intracellularly but also provides a new pathway for highly processive DNA nanomachines, offering a new avenue for bioanalysis and early clinical diagnosis.

Evaluation of Spontaneous DNA Damage Using the Alkaline Comet Assay in Lymphocyte Cells of Humans Living in the High Level Natural Radiation Area of Mamuju, Indonesia

To evaluate the biological impacts of high background radiation exposures that are represented by spontaneous deoxyribonucleic acid (DNA) damage, an evaluation on lymphocyte cells from residents of Mamuju, West Sulawesi, Indonesia was tested. The mean annual dose received by individuals in this area is about 10.40 mSv. Of the 177 adult subjects studied, 102 were from high-level natural radiation areas of Mamuju and 75 subjects were from a nearby normal-level natural radiation area. Both areas are similar in living situations. DNA strand breaks and other parameters of study and control group were determined using a standardized comet assay. Our results showed that chronic low-level natural radiation had resulted in significantly higher (p&lt;0.001) DNA damage based on the three parameters of the assay (tail length, tail DNA, and tail moment) compared to those of control. There was a positive correlation between the level of DNA damage and age, where people aged 40 years and older had a higher level of DNA damage than those under 40 year. The level of DNA damage was also found to be higher in females compared to that of males. It was concluded that chronic exposure to natural radiation in Mamuju had induced spontaneous DNA damage in human cells after long-term exposure which was dependent on age and sex.

Plaque-Targeted Rapamycin Spherical Nucleic Acids for Synergistic Atherosclerosis Treatment.

Atherosclerosis with unstable plaques is the dominant pathological basis of lethal cardio‐cerebrovascular diseases, which can cause acute death due to the rupture of plaques. Plaque‐targeted drug delivery to achieve promoted treatment remains the main challenge because of the systemic occurrence of atheroma. Herein, a rapamycin (RAP) spherical nucleic acid (SNA) structure, capable of specifically accumulating in plaques for synergistic atherosclerosis treatment is constructed. By designing consecutive phosphorothioate (PS) at 3’ terminus of the deoxyribonucleic acid (DNA) strand, multiple hydrophobic RAPs are covalently grafted onto the PS segment to form an amphiphilic drug‐grafted DNA (RAP‐DNA), which successively self‐assembles into micellar SNA (RAP‐SNA). Moreover, the phosphodiester‐DNA segment constitutes the outer shell of RAP‐SNA, enabling further hybridization with functional siRNA (targeting lectin‐like oxidized low‐density lipoprotein receptor‐1, LOX‐1) to obtain the drug codelivered SNA (LOX‐1/RAP‐SNA). With two active ingredients inside, LOX‐1/RAP‐SNA can not only induce robust autophagy and decrease the evil apoptosis of the pathological macrophages, but also simultaneously prohibit the LOX‐1‐mediated formation of damageable foam cells, realizing the effect of synergistic therapy. As a result, the LOX‐1/RAP‐SNA significantly reduces the progression of atheroma and stabilizes the plaques, providing a new strategy for synergistically targeted atherosclerosis treatment.

An Operational DNA Strand Displacement Encryption Approach.

DeoxyriboNucleic Acid (DNA) encryption is a new encryption method that appeared along with the research of DNA nanotechnology in recent years. Due to the complexity of biology in DNA nanotechnology, DNA encryption brings in an additional difficulty in deciphering and, thus, can enhance information security. As a new approach in DNA nanotechnology, DNA strand displacement has particular advantages such as being enzyme free and self-assembly. However, the existing research on DNA-strand-displacement-based encryption has mostly stayed at a theoretical or simulation stage. To this end, this paper proposes a new DNA-strand-displacement-based encryption framework. This encryption framework involves three main strategies. The first strategy was a tri-phase conversion from plaintext to DNA sequences according to a Huffman-coding-based transformation rule, which enhances the concealment of the information. The second strategy was the development of DNA strand displacement molecular modules, which produce the initial key for information encryption. The third strategy was a cyclic-shift-based operation to extend the initial key long enough, and thus increase the deciphering difficulty. The results of simulation and biological experiments demonstrated the feasibility of our scheme for encryption. The approach was further validated in terms of the key sensitivity, key space, and statistic characteristic. Our encryption framework provides a potential way to realize DNA-strand-displacement-based encryption via biological experiments and promotes the research on DNA-strand-displacement-based encryption.