Small molecule-induced DNA hydrogel with encapsulation and release properties

Oligo-Adenine Derived Secondary Nucleic Acid Frameworks: From Structural Characteristics to Applications

Oligo-adenine (polyA) is primarily known for its critical role in mRNA stability, translational status, and gene regulation. Beyond its biological functions, extensive research has unveiled the diverse applications of polyA. In response to environmental stimuli, single polyA strands undergo distinctive structural transitions into diverse secondary configurations, which are reversible upon the introduction of appropriate counter-triggers. In this review, we systematically summarize recent advances of noncanonical structures derived from polyA, including A-motif duplex, A-cyanuric acid triplex, A-coralyne-A duplex, and T ⋅ A-T triplex. The structural characteristics and mechanisms underlying these conformations under specific external stimuli are addressed, followed by examples of their applications in stimuli-responsive DNA hydrogels, supramolecular fibre assembly, molecular electronics and switches, biosensing and bioengineering, payloads encapsulation and release, and others. A detailed comparison of these polyA-derived noncanonical structures is provided, highlighting their distinctive features. Furthermore, by integrating their stimuli-responsiveness and conformational characteristics, advanced material development, such as pH-cascaded DNA hydrogels and supramolecular fibres exhibiting dynamic structural transitions adapting environmental cues, are introduced. An outlook for future developments is also discussed. These polyA derived, stimuli-responsive, noncanonical structures enrich the arsenal of DNA "toolbox", offering dynamic DNA frameworks for diverse future applications.

Research progress of loop-mediated isothermal amplification in the detection of Salmonella for food safety applications

Salmonella, the prevailing zoonotic pathogen within the Enterobacteriaceae family, holds the foremost position in global bacterial poisoning incidents, thereby signifying its paramount importance in public health. Consequently, the imperative for expeditious and uncomplicated detection techniques for Salmonella in food is underscored. After more than two decades of development, loop-mediated isothermal amplification (LAMP) has emerged as a potent adjunct to the polymerase chain reaction, demonstrating significant advantages in the realm of isothermal amplification. Its growing prominence is evident in the increasing number of reports on its application in the rapid detection of Salmonella. This paper provides a systematic exposition of the technical principles and characteristics of LAMP, along with an overview of the research progress made in the rapid detection of Salmonella using LAMP and its derivatives. Additionally, the target genes reported in various levels, including Salmonella genus, species, serogroup, and serotype, are summarized, aiming to offer a valuable reference for the advancement of LAMP application in Salmonella detection. Finally, we look forward to the development direction of LAMP and expect more competitive methods to provide strong support for food safety applications.

A Cautionary Perspective on Hydrogel-Induced Concentration Gradient Generation for Studying Chemotaxis

The achievement of consistent and static chemical gradients is critically important in the study of diffusion and chemotaxis at the micro- and nanoscales. In this context, a number of groups have reported on hydrogel-based systems for generating concentration gradients. Here, we analyze the behavior of agarose and gelatin-based hydrogels in hybridization chambers of different heights. Our focus is on the issues that are caused by the presence of robust bulk fluid flows in such systems due to the solutes present in the hydrogel and/or the surrounding fluid. We describe the key insights derived from these experiments, offering practical guidelines for establishing gradients using hydrogel-based systems and make the community aware of different variables that can make the experiments nonreproducible and prone to misinterpretations.

Oligo-Adenine and Cyanuric Acid Supramolecular DNA-Based Hydrogels Exhibiting Acid-Resistance and Physiological pH-Responsiveness

Expanding the functions and applications of DNA by integrating noncanonical bases and structures into biopolymers is a continuous scientific effort. An adenine-rich strand (A-strand) is introduced as functional scaffold revealing, in the presence of the low-molecular-weight cofactor cyanuric acid (CA, pKa 6.9), supramolecular hydrogel-forming efficacies demonstrating multiple pH-responsiveness. At pH 1.2, the A-strand transforms into a parallel A-motif duplex hydrogel cross-linked by AH+-H+A units due to the protonation of adenine (pKa 3.5). At pH 5.2, and in the presence of coadded CA, a helicene-like configuration is formed between adenine and protonated CA, generating a parallel A-CA triplex cross-linked hydrogel. At pH 8.0, the hydrogel undergoes transition into a liquid state by deprotonation of CA cofactor units and disassembly of A-CA triplex into its constituent components. Density functional theory calculations and molecular dynamics simulations, supporting the structural reconfigurations of A-strand in the presence of CA, are performed. The sequential pH-stimulated hydrogel states are rheometrically characterized. The hydrogel framework is loaded with fluorescein-labeled insulin, and the pH-stimulated release of insulin from the hydrogel across the pH barriers present in the gastrointestinal tract is demonstrated. The results provide principles for future application of the hydrogel for oral insulin administration for diabetes.

Injectable hydrogels as emerging drug-delivery platforms for tumor therapy

Tumor therapy continues to be a prominent field within biomedical research. The development of various drug carriers has been propelled by concerns surrounding the side effects and targeting efficacy of various chemotherapeutic drugs and other therapeutic agents. These carriers strive to enhance drug concentration at tumor sites, minimize systemic side effects, and improve therapeutic outcomes. Among the reported delivery systems, injectable hydrogels have emerged as an emerging candidate for the in vivo delivery of chemotherapeutic drugs due to their minimal invasive drug delivery properties. This review systematically summarizes the composition and preparation methodologies of injectable hydrogels and further highlights the delivery mechanisms of diverse drugs using these hydrogels for tumor therapy, along with an in-depth discussion on the optimized therapeutic efficiency of drugs encapsulated within the hydrogels. The work concludes by providing a dynamic forward-looking perspective on the potential challenges and possible solutions of the in situ injectable hydrogels for non-surgical and real-time diagnostic applications.

Recent status and trends of nanotechnology in cervical cancer: a systematic review and bibliometric analysis

Background

Cervical cancer is currently the second leading cause of cancer death among women from developing countries (1). However, there is a lack of effective treatment methods, and the existing treatments often result in significant adverse reactions and high chances of recurrence, which ultimately impact the prognosis of patients. As a result, the application of nanotechnology, specifically nanoparticle-based approaches, in the diagnosis and treatment of cervical cancer has gained significant attention. This study aims to examine the current research status and future development trends of nanotechnology in relation to cervical cancer using a bibliometric perspective.

Methods

A bibliometric analysis was performed to gather relevant research papers from the Web of Science database. VOSviewer and CiteSpace were utilized to conduct quantitative analysis and identify hot topics in the field, focusing on countries, institutions, journals, authors, and keywords.

Result

A total of 997 eligible literature were retrieved. From January 1, 2014 to September 20, 2023, the overall number of publications showed an upward trend. The paper mainly comes from China (n=414). The main institution is the Chinese Academy of Sciences (n=62), and 60% of the top 10 institutions in the number of documents issued are from China. First authors Ma, Rong (n=12) and Alifu, Nuernisha (n=12). The journal with the highest publication volume is ACS Applied Materials&INTERFACES (n=35), and the journal with the highest citation frequency is BIOMATERIALS (n=508). "Nanoparticles (n=295)", "cervical cancer (n=248)", and "drug delivery (n=218)" are the top three most frequently occurring keywords. In recent years, photothermal therapy and indocyanine green have become research hotspots.

Conclusion

The application of nanotechnology in the field of cervical cancer has garnered considerable attention. Nanoparticles-based methods for diagnosis, administration, and treatment have proven to be instrumental in enhancing the sensitivity of cervical cancer detection, improving the accuracy and efficiency of administration, and reducing drug toxicity. Enhancing treatment efficacy and improving patient prognosis have emerged as current research priorities and future directions.

Small Molecule-Templated DNA Hydrogel with Record Stiffness Integrates and Releases DNA Nanostructures and Gene Silencing Nucleic Acids

Deoxyribonucleic acid (DNA) hydrogels are a unique class of programmable, biocompatible materials able to respond to complex stimuli, making them valuable in drug delivery, analyte detection, cell growth, and shape-memory materials. However, unmodified DNA hydrogels in the literature are very soft, rarely reaching a storage modulus of 10³  Pa, and they lack functionality, limiting their applications. Here, a DNA/small-molecule motif to create stiff hydrogels from unmodified DNA, reaching 10⁵  Pa in storage modulus is used. The motif consists of an interaction between polyadenine and cyanuric acid-which has 3-thymine like faces-into multimicrometer supramolecular fibers. The mechanical properties of these hydrogels are readily tuned, they are self-healing and thixotropic. They integrate a high density of small, nontoxic molecules, and are functionalized simply by varying the molecule sidechain. They respond to three independent stimuli, including a small molecule stimulus. These stimuli are used to integrate and release DNA wireframe and DNA origami nanostructures within the hydrogel. The hydrogel is applied as an injectable delivery vector, releasing an antisense oligonucleotide in cells, and increasing its gene silencing efficacy. This work provides tunable, stimuli-responsive, exceptionally stiff all-DNA hydrogels from simple sequences, extending these materials' capabilities.

A simple method for fabricating drugs containing a cis-o-diol structure into guanosine-based supramolecular hydrogels for drug delivery

Supramolecular hydrogels are attractive biomaterials for local drug delivery owing to their excellent self-healing, injectable, biodegradable, and biocompatible properties. However, traditional drug-loading approaches based on non-covalent encapsulation and covalent bonding have shown problems such as rapid or difficult drug release, complex reaction processes, low reaction efficiency, and decreased drug activity. Therefore, there is a need to find a simple and efficient method to load drugs into hydrogels, which possess stable drug release ability without impairing drug efficacy. In this study, we introduce dynamic borate ester bonds via a simple one-pot method to load cis-o-diol-containing drugs into guanosine (G)-based supramolecular hydrogels. The experimental results confirm that the dynamic covalent borate ester bonds are formed based on the cis-o-diol groups of the drug and the G in these hydrogels. Meanwhile, the as-prepared G-based hydrogels not only possess self-healing properties and injectability but also have satisfactory biodegradability and biocompatibility. Additionally, the drug can be released from the G-based hydrogel according to the pH-responsive cleavage of the borate ester bonds without affecting drug activity. Overall, these results indicate that the simple one-pot method of utilizing the dynamic borate bond can provide a valuable reference for the design of hydrogel dosage forms.

Switching the Mode of Drug Release from a Reaction-Coupled Low-Molecular-Weight Gelator System by Altering Its Reaction Pathway

Low-molecular-weight hydrogels are attractive scaffolds for drug delivery applications because of their modular and facile preparation starting from inexpensive molecular components. The molecular design of the hydrogelator results in a commitment to a particular release strategy, where either noncovalent or covalent bonding of the drug molecule dictates its rate and mechanism. Herein, we demonstrate an alternative approach using a reaction-coupled gelator to tune drug release in a facile and user-defined manner by altering the reaction pathway of the low-molecular-weight gelator (LMWG) and drug components through an acylhydrazone-bond-forming reaction. We show that an off-the-shelf drug with a reactive handle, doxorubicin, can be covalently bound to the gelator through its ketone moiety when the addition of the aldehyde component is delayed from 0 to 24 h, or noncovalently bound with its addition at 0 h. We also examine the use of an l-histidine methyl ester catalyst to prepare the drug-loaded hydrogels under physiological conditions. Fitting of the drug release profiles with the Korsmeyer-Peppas model corroborates a switch in the mode of release consistent with the reaction pathway taken: increased covalent ligation drives a transition from a Fickian to a semi-Fickian mode in the second stage of release with a decreased rate. Sustained release of doxorubicin from the reaction-coupled hydrogel is further confirmed in an MTT toxicity assay with MCF-7 breast cancer cells. We demonstrate the modularity and ease of the reaction-coupled approach to prepare drug-loaded self-assembled hydrogels in situ with tunable mechanics and drug release profiles that may find eventual applications in macroscale drug delivery.

Light responsive nucleic acid for biomedical application

Nucleic acids are widely used in biomedical applications because of their programmability and biocompatibility. The light responsive nucleic acids have attracted wide attention due to their remote control and high spatiotemporal resolution. In this review, we summarized the latest developments in biomedicine of light responsive molecules. The molecules which confer light responsive properties to nucleic acids were summarized. The binding sites of molecules to nucleic acids, the induced structural changes, and functional regulation of nucleic acids were reviewed. Then, the biomedical applications of light responsive nucleic acids were listed, such as drug delivery, biosensing, optogenetics, gene editing, etc. Finally, the challenges were discussed and possible future directions of light-responsive nucleic acids were proposed.

Smart Nucleic Acid Hydrogels with High Stimuli-Responsiveness in Biomedical Fields

Due to their hydrophilic, biocompatible and adjustability properties, hydrogels have received a lot of attention. The introduction of nucleic acids has made hydrogels highly stimuli-responsiveness and they have become a new generation of intelligent biomaterials. In this review, the development and utilization of smart nucleic acid hydrogels (NAHs) with a high stimulation responsiveness were elaborated systematically. We discussed NAHs with a high stimuli-responsiveness, including pure NAHs and hybrid NAHs. In particular, four stimulation factors of NAHs were described in details, including pH, ions, small molecular substances, and temperature. The research progress of nucleic acid hydrogels in biomedical applications in recent years is comprehensively discussed. Finally, the opportunities and challenges facing the future development of nucleic acid hydrogels are also discussed.

A portable thermal detection method based on the target responsive hydrogel mediated self-heating of a warming pad

A simple thermal aptasensing platform was devised for the sensitive detection of organophosphate pesticides (using malathion as a model target) based on the efficient self-heating reaction of a warming pad with a switchable target responsive enzyme-encapsulated three-dimensional (3D) DNA hydrogel using a portable thermometer as a signal readout in this work. The existence of the target malathion would open the catalase-3D network and lots of catalase was released from the hydrogel, which could efficiently convert H₂O₂ to an O₂ molecule. The product O₂ is the critical condition for the self-heating of the warming pad. Thereafter, the temperature was enhanced with the increasing amount of O₂. The strategy displays outstanding specificity, reproducibility and stability. Moreover, this method can be easily extended to monitor other molecules using different aptamer sequences in practical applications.