Structures and Applications of Nucleic Acid-Based Micelles for Cancer Therapy

Nucleic acids have become important building blocks in nanotechnology over the last 30 years. DNA and RNA can sequentially build specific nanostructures, resulting in versatile drug delivery systems. Self-assembling amphiphilic nucleic acids, composed of hydrophilic and hydrophobic segments to form micelle structures, have the potential for cancer therapeutics due to their ability to encapsulate hydrophobic agents into their core and position functional groups on the surface. Moreover, DNA or RNA within bio-compatible micelles can function as drugs by themselves. This review introduces and discusses nucleic acid-based spherical micelles from diverse amphiphilic nucleic acids and their applications in cancer therapy.

Detection and utility of cell-free and circulating tumour DNA in bone and soft-tissue sarcomas

Aims

Cell-free DNA (cfDNA) and circulating tumour DNA (ctDNA) are used for prognostication and monitoring in patients with carcinomas, but their utility is unclear in sarcomas. The objectives of this pilot study were to explore the prognostic significance of cfDNA and investigate whether tumour-specific alterations can be detected in the circulation of sarcoma patients.

Methods

Matched tumour and blood were collected from 64 sarcoma patients (n = 70 samples) prior to resection of the primary tumour (n = 57) or disease recurrence (n = 7). DNA was isolated from plasma, quantified, and analyzed for cfDNA. A subset of cases (n = 6) underwent whole exome sequencing to identify tumour-specific alterations used to detect ctDNA using digital droplet polymerase chain reaction (ddPCR).

Results

Cell-free was present in 69 of 70 samples above 0.5 ng/ml. Improved disease-free survival was found for patients with lower cfDNA levels (90% vs 48% at one-year for ≤ 6 ng/ml and > 6 ng/ml, respectively; p = 0.005). Digital droplet PCR was performed as a pilot study and mutant alleles were detectable at 0.5% to 2.5% of the wild type genome, and at a level of 0.25 ng tumour DNA. Tumour-specific alterations (ctDNA) were found in five of six cases.

Conclusion

This work demonstrates the feasibility and potential utility of cfDNA and ctDNA as biomarkers for bone and soft-tissue sarcomas, despite the lack of recurrent genomic alterations. A larger study is required to validate these findings.

Cite this article: Bone Joint Res 2021;10(9):602–610.

Regulating Catalytic Activity of DNA-Templated Silver Nanoclusters Based on their Differential Interactions with DNA Structures and Stimuli-Responsive Structural Transition

This work reports exquisite engineering of catalytic activity of DNA-templated silver nanoclusters (DNA-AgNCs) based on unique adsorption phenomena of DNAs on DNA-AgNCs and reversible transition between double and triple-stranded DNAs. Four DNA homopolymers exhibit different inhibition effects on the catalytic activity of DNA-AgNCs, poly adenine (polyA) > poly guanine (polyG) > poly cytosine (polyC) > poly thymine (polyT), demonstrating that polyA strands have the strongest adsorption affinity on DNA-AgNCs. Through the formation of T-A•T triplex DNAs, catalytic activity of DNA-AgNCs is restored from the deactivated state by double or single-stranded DNAs, indicating the participation of N7 groups of adenine bases in binding to DNA-AgNCs and blocking active sites. Accordingly, reversibly regulating catalytic activity of DNA-AgNCs can be realized based on DNA input-stimulated transition between duplex and triplex structures. In the end, two low-cost and facile biosensing methods are presented, which are derived from the activity-switchable platform. It is worthy to anticipate that the DNA-AgNCs with controlled catalytic activity will inspire researchers to devise more functionalized nanocatalysts and contribute to the exploration of intelligent biomedicine in the future.

Organic Semiconductor-DNA Hybrid Assemblies

Organic semiconductors are photonic and electronic materials with high luminescence, quantum efficiency, color tunability, and size-dependent optoelectronic properties. The self-assembly of organic molecules enables the establishment of a fabrication technique for organic micro- and nano-architectures with well-defined shapes, tunable sizes, and defect-free structures. DNAs, a class of biomacromolecules, have recently been used as an engineering material capable of intricate nanoscale structuring while simultaneously storing biological genetic information. Here, the up-to-date research on hybrid materials made from organic semiconductors and DNAs is presented. The trends in photonic and electronic phenomena discovered in DNA-functionalized and DNA-driven organic semiconductor hybrids, comprising small molecules and polymers, are observed. Various hybrid forms of solutions, arrayed chips, nanowires, and crystalline particles are discussed, focusing on the role of DNA in the hybrids. Furthermore, the recent technical advances achieved in the integration of DNAs in light-emitting devices, transistors, waveguides, sensors, and biological assays are presented. DNAs not only serve as a recognizing element in organic-semiconductor-based sensors, but also as an active charge-control material in high-performance optoelectronic devices.

Chemiluminescence Resonance Energy Transfer-Based Mesoporous Silica Nanosensors for the Detection of miRNA

The chemiluminescence resonance energy transfer (CRET)-based method is free of autofluorescence interference, which can achieve an extremely high signal-to-background ratio for detection. Nevertheless, this method is still hindered by the inner filter effect, quenching effect, and nonspecific absorption of reported nanoparticles. Herein, mesoporous silica nanomaterials (MSNs) acted as carriers to load both the donor (horseradish peroxidase, HRP) and the acceptor (a functional DNA duplex). This approach realized the construction of a new CRET-based nanosensor for the sensitive detection of miRNA. By controlling the energy-transfer distance with the designed DNAs, the donor emission at 430 nm could be quenched by the adsorption of the dye labeled on the acceptor DNA. The CRET system could be destroyed by releasing acceptor DNA from linker DNA via the competitive hybridization of target miRNA, resulting in emission recovery for quantification. With the cancer biomarker miR-155 as the model, the sensitive and selective detection of miR-155 was achieved, which showed high energy-transfer efficiency, good specificity, favorable biodegradability, and low toxicity. This work provides a potential pathway for biological detection and clinical diagnosis.

Formation of Neural Circuits in an Expanded Version of Darwin's Theory: Effects of DNAs in Extra Dimensions and within the Earth's Core on Neural Networks

AIM:

In this paper, inspiring Darwin’s theory, we propose a model which connects evolutions of neural circuits with evolutions of cosmos. In this model, in the beginning, there are some closed strings which decay into two groups of open strings.

METHODS:

First group couple to our universe from one side and produce matters like some genes of DNAs and couple to an anti-universe from another side with opposite sign and create anti-matters like some anti-genes of anti-DNAs. Second group couple to the star and planet’s cores like the earth’s core from one side and produce anti-matters like stringy black anti-DNA and couple to outer layers of stars and planets like the earth from other side and produce matters like some genes of DNAs on the earth. Each DNA or anti-DNA contains some genetic circuits which act like the circuits of receiver or sender of radio waves. To transfer waves of these circuits, some neurons emerge which some of them are related to genetic circuits of anti-DNAs in anti-universe, and some are related to genetic circuits of stringy black anti-DNA within the earth’s core. A collection of these neural circuits forms the little brain on the heart at first and main brain after some time.

RESULTS:

To examine the model, we remove effects of matters in outer layers of earth in the conditions of microgravity and consider radiated signals of neural circuits in a chick embryo. We observe that in microgravity, more signals are emitted by neural circuits respect to normal conditions. This is a signature of exchanged waves between neural circuits and structures within the earth’s core.

CONCLUSION:

These communications help some animals to predict the time and place of an earthquake.

A Multi-Fluorescent DNA/Graphene Oxide Conjugate Sensor for Signature-Based Protein Discrimination

Signature-based protein sensing has recently emerged as a promising prospective alternative to conventional lock-and-key methods. However, most of the current examples require the measurement of optical signals from spatially-separated materials for the generation of signatures. Herein, we present a new approach for the construction of multi-fluorescent sensing systems with high accessibility and tunability, which allows generating protein fluorescent signatures from a single microplate well. This approach is based on conjugates between nano-graphene oxide (nGO) and three single-stranded DNAs (ssDNAs) that exhibit different sequences and fluorophores. Initially, the three fluorophore-modified ssDNAs were quenched simultaneously by binding to nGO. Subsequent addition of analyte proteins caused a partial recovery in fluorescent intensity of the individual ssDNAs. Based on this scheme, we have succeeded in acquiring fluorescence signatures unique to (i) ten proteins that differ with respect to pI and molecular weight and (ii) biochemical marker proteins in the presence of interferent human serum. Pattern-recognition methods demonstrated high levels of discrimination for this system. The high discriminatory power and simple format of this sensor system should enable an easy and fast evaluation of proteins and protein mixtures.

Nanoparticle-Programmed Surface for Drug Release and Cell Regulation via Reversible Hybridization Reaction

A surface directly connects the bulk of a material to its surroundings. The ability to dynamically regulate the surface without affecting the bulk of a material holds great potential for new applications. The purpose of this work was to demonstrate that the surface can be dynamically changed using nanoparticles and oligonucleotides (ODNs) in a reversible and reiterative manner. A dual-functional nanogel was synthesized as the model of nanoparticles using miniemulsion polymerization and click chemistry. The nanogel can not only adsorb drugs for sustained drug release but also bind a surface functionalized with complementary ODNs. Importantly, hybridization reaction and ODN degradation can drive reversible and reiterative nanogel binding to the surface for dynamic change, which in principle is unlimited. Moreover, nanogel-mediated dynamic change offers the surface with the drug-releasing function for inhibiting the growth of surrounding cells. Because nanogels can be replaced by any functional nanoparticles with a diverse array of properties, nanoparticle-programmed surface change constitutes a promising platform for various applications such as drug delivery and stent implantation.

Getting patients in the door: medical appointment reminder preferences

PURPOSE

Between 23% and 34% of outpatient appointments are missed annually. Patients who frequently miss medical appointments have poorer health outcomes and are less likely to use preventive health care services. Missed appointments result in unnecessary costs and organizational inefficiencies. Appointment reminders may help reduce missed appointments; particular types may be more effective than other types. We used a survey with a discrete choice experiment (DCE) to learn why individuals miss appointments and to assess appointment reminder preferences.

METHODS

We enrolled a national sample of adults from an online survey panel to complete demographic and appointment habit questions as well as a 16-task DCE designed in Sawtooth Software's Discover tool. We assessed preferences for four reminder attributes - initial reminder type, arrival of initial reminder, reminder content, and number of reminders. We derived utilities and importance scores.

RESULTS

We surveyed 251 adults nationally, with a mean age of 43 (range 18-83) years: 51% female, 84% White, and 8% African American. Twenty-three percent of individuals missed one or more appointments in the past 12 months. Two primary reasons given for missing an appointment include transportation problems (28%) and forgetfulness (26%). Participants indicated the initial reminder type (21%) was the most important attribute, followed by the number of reminders (10%). Overall, individuals indicated a preference for a single reminder, arriving via email, phone call, or text message, delivered less than 2 weeks prior to an appointment. Preferences for reminder content were less clear.

CONCLUSION

The number of missed appointments and reasons for missing appointments are consistent with prior research. Patient-centered appointment reminders may improve appointment attendance by addressing some of the reasons individuals report missing appointments and by meeting patients' needs. Future research is necessary to determine if preferred reminders used in practice will result in improved appointment attendance in clinical settings.

'Did not attends' in children 0-10: a scoping review

Patients who do not attend ('DNA') health appointments have been identified as a service problem incurring significant costs to the NHS. In order to explore the causes, effects and costs of child DNAs, we carried out a scoping study to map the literature and identify gaps in the research. Given the breadth of issues underpinning DNAs, a scoping study, including research studies, audits, policy documents and conference abstracts, was the most useful way to map the field. To foster public and patient participation, we sought advice from parents participating in the National Children's Bureau's Family Research Advisory Group. From a pool of 1997 items, we found few UK studies with non-attendance of 0-10 year olds as a primary focus, though many more incidentally reported DNA rates. Overall, four topics predominated: the conceptualization of DNAs; the correlates of non-attendance; initiatives to reduce non-attendance; and the relationship between non-attendance and safeguarding. The Family Research Advisory Group identified broadly similar issues, but with a stronger emphasis on communication and practical matters. While there may be circumstances where failing to attend appointments makes little or no difference to a child (or even benefits them) it is likely that there are children whose health or well-being are compromised as a result of failing to attend appointments. Both 'over' and 'under'-attendance can be a source of anxiety to health professionals. Areas where further work is needed include robust evaluation of the effectiveness, cost-effectiveness and maintenance of measures to reduce DNAs and a better understanding of the relationship of safeguarding to non-attendance.