Advances in intracellular delivery through supramolecular self-assembly of oligonucleotides and peptides

Rational design of peptides to overcome drug resistance by metabolic regulation

Chemotherapy is widely used clinically, however, its efficacy is often compromised by the development of drug resistance, which arises from prolonged administration of drugs or other stimuli. One of the driven causes of drug resistance in tumors or bacterial infections is metabolic reprogramming, which alters mitochondrial metabolism, disrupts metabolic pathways and causes ion imbalance. Bioactive peptide materials, due to their biocompatibility, diverse bioactivities, customizable sequences, and ease of modification, have shown promise in overcoming drug resistance. This review provides an in-depth analysis of metabolic reprogramming and associated microenvironmental changes that contribute to drug resistance in common tumors and bacterial infections, suggesting potential therapeutic targets. Additionally, we explore peptide-based materials for regulating metabolism and their potential synergic effect with other therapies, highlighting the mechanisms by which these peptides reverse drug resistance. Finally, we discuss future perspectives and the clinical challenges in peptide-based treatments, aiming to offer insights for overcoming drug-resistant diseases.

How Advanced are Self-Assembled Nanomaterials for Targeted Drug Delivery? A Comprehensive Review of the Literature

The development of effective drug delivery systems is a key focus in pharmaceutical research, aiming to enhance therapeutic efficacy while minimizing adverse effects. Self-assembled nanostructures present a promising solution due to their tunable properties, biocompatibility, and ability to encapsulate and deliver therapeutic agents to specific targets. This review examines recent advancements in drug-based self-assembled nanostructures for targeted delivery applications, including drug-drug conjugates, polymeric-based architectures, biomolecules, peptides, DNA, squalene conjugates and amphiphilic drugs. Various strategies for fabricating these nanostructures are discussed, with an emphasis on the design principles and mechanisms underlying their self-assembly and potential for targeted drug delivery to specific tissues or cells. Furthermore, the integration of targeting ligands, stimuli-responsive moieties and imaging agents into these nanostructures is explored for enhanced therapeutic outcomes and real-time monitoring. Challenges such as stability, scalability and regulatory hurdles in translating these nanostructures from bench to bedside are also addressed. Drug-based self-assembled nanostructures represent a promising platform for developing next-generation targeted drug delivery systems with improved therapeutic efficacy and reduced side effects.

1D, 3D supramolecular assemblies of a series of cyclometalated platinum(II) complexes with deep-red aggregation-induced phosphorescent emission and anion turn-on sensing via Pt-Pt interaction

Controlling the size and morphology of supramolecular assemblies is still an enormous challenge for the development of novel functional materials. Herein, cyclometalated platinum(II) complexes were designed and used as effective theragnostic supramolecular nano agents. Benzoquinoline was used as the main C^N ligand, and the increased number of aromatic rings in the N^N ligand of Pt complexes could greatly improve lipophilicity and cytotoxicity towards cancer cells over normal cells. Moreover, the morphology of nanoparticles formed by self-assembly of Pta-d could change from one to three-dimensional (1-3D), which can form nanowires and nanospheres. Besides, complexes of Pta-c, the number of aromatic rings in the N^N ligand of which does not exceed 4, all exhibit significant aggregation-induced phosphorescent emission (AIPE) with 100 - 200-fold enhancement in red phosphoresce intensity recorded in the solvent of Pta-1 and Ptb. Pt-Pt interaction induced by coordination and electrostatic interaction between complex and anions, and a new deep red emission improvement was observed in aqueous solution of Pta and Ptb with the presence of ClO4-, and two similar deep red emissions induced by two different interactions can be told by new emerging MMLCT absorption band. Ptd of dppz ligand exhibits the highest efficiency in inducing apoptosis of HeLa and its anticancer mechanism was studied. Our work aims to promote the fundamental comprehension of the self-assembly behavior of cyclometalated platinum complex with AIPE in vitro and living cells.

Thermoresponsive and Supramolecular Polymers: Interesting Biomaterials for Drug Delivery

How to use and deliver drugs to diseased and damaged areas has been one of the main concerns of pharmacologists and doctors for a long time. With the efforts of researchers, the advancement of technology, and the involvement of engineering in the health field, diverse and promising approaches have been studied and used to achieve this goal. A better understanding of biomaterials and the ability of production equipment led researchers to offer new drug delivery systems to the world. In recent decades, responsive polymers (exclusively to temperature and pH) and supramolecular polymers have received much attention due to their unique capabilities. Although this field of research still needs to be scrutinized and studied more, their recognition, examination, and use as drug delivery systems is a start for a promising future. This review study, focusing on temperature-responsive and supramolecular biomaterials and their application as drug delivery systems, deals with their structure, properties, and role in the noninvasive and effective delivery of medicinal agents.

Short Peptides as Powerful Arsenal for Smart Fighting Cancer

Short peptides have been coming around as a strong weapon in the fight against cancer on all fronts-in immuno-, chemo-, and radiotherapy, and also in combinatorial approaches. Moreover, short peptides have relevance in cancer imaging or 3D culture. Thanks to the natural 'smart' nature of short peptides, their unique structural features, as well as recent progress in biotechnological and bioinformatics development, short peptides are playing an enormous role in evolving cutting-edge strategies. Self-assembling short peptides may create excellent structures to stimulate cytotoxic immune responses, which is essential for cancer immunotherapy. Short peptides can help establish versatile strategies with high biosafety and effectiveness. Supramolecular short peptide-based cancer vaccines entered clinical trials. Peptide assemblies can be platforms for the delivery of antigens, adjuvants, immune cells, and/or drugs. Short peptides have been unappreciated, especially in the vaccine aspect. Meanwhile, they still hide the undiscovered unlimited potential. Here, we provide a timely update on this highly active and fast-evolving field.

Pulsed Dipolar EPR for Self-Limited Complexes of Oligonucleotides Studies

Pulsed electron-electron double resonance (PELDOR) spectroscopy is a powerful method for determining nucleic acid (NA) structure and conformational dynamics. PELDOR with molecular dynamics (MD) simulations opens up unique possibilities for defining the conformational ensembles of flexible, three-dimensional, self-assembled complexes of NA. Understanding the diversity and structure of these complexes is vital for uncovering matrix and regulative biological processes in the human body and artificially influencing them for therapeutic purposes. To explore the reliability of PELDOR and MD simulations, we site-specifically attached nitroxide spin labels to oligonucleotides, which form self-assembled complexes between NA chains and exhibit significant conformational flexibility. The DNA complexes assembled from a pair of oligonucleotides with different linker sizes showed excellent agreement between the distance distributions obtained from PELDOR and calculated from MD simulations, both for the mean inter-spin distance and the distance distribution width. These results prove that PELDOR with MD simulations has significant potential for studying the structure and dynamics of conformational flexible complexes of NA.

Fluoride-Ion-Responsive Sol-Gel Transition in an L-Cysteine/AgNO3 System: Self-Assembly Peculiarities and Anticancer Activity

Supramolecular hydrogels based on low-molecular-weight compounds are a unique class of so-called "soft" materials, formed by weak non-covalent interactions between precursors at their millimolar concentrations. Due to the variety of structures that can be formed using different low-molecular-weight gelators, they are widely used in various fields of technology and medicine. In this study, we report for the first time an unusual self-assembly process of mixing a hydrosol obtained from L-cysteine and silver nitrate (cysteine-silver sol-CSS) with sodium halides. Modern instrumental techniques such as viscosimetry, UV spectroscopy, dynamic light scattering, zeta potential measurements, SEM and EDS identified that adding fluoride anions to CSS is able to form stable hydrogels of a thixotropic nature, while Cl-, Br- and I- lead to precipitation. The self-assembly process proceeds using a narrow concentration range of F-. An increase in the fluoride anion content in the system leads to a change in the gel network morphology from elongated structures to spherical ones. This fact is reflected in a decrease in the gel viscosity and a number of gel-sol-gel transition cycles. The mechanism of F-'s interaction with hydrosol includes the condensation of anions on the positive surface of the CSS nanoparticles, their binding via electrostatic forces and the formation of a resulting gel carcass. In vitro analysis showed that the hydrogels suppressed human squamous carcinoma cells at a micromolar sample concentration. The obtained soft gels could have potential applications against cutaneous malignancy and as carriers for fluoride anion and other bioactive substance delivery.

Bimodal DNA self-origami material with nucleic acid function enhancement

BACKGROUND

The design of DNA materials with specific nanostructures for biomedical tissue engineering applications remains a challenge. High-dimensional DNA nanomaterials are difficult to prepare and are unstable; moreover, their synthesis relies on heavy metal ions. Herein, we developed a bimodal DNA self-origami material with good biocompatibility and differing functions using a simple synthesis method. We simulated and characterized this material using a combination of oxDNA, freeze-fracture electron microscopy, and atomic force microscopy. Subsequently, we optimized the synthesis procedure to fix the morphology of this material.

RESULTS

Using molecular dynamics simulation, we found that the bimodal DNA self-origami material exhibited properties of spontaneous stretching and curling and could be fixed in a single morphology via synthesis control. The application of different functional nucleic acids enabled the achievement of various biological functions, and the performance of functional nucleic acids was significantly enhanced in the material. Consequently, leveraging the various functional nucleic acids enhanced by this material will facilitate the attainment of diverse biological functions.

CONCLUSION

The developed design can comprehensively reveal the morphology and dynamics of DNA materials. We thus report a novel strategy for the construction of high-dimensional DNA materials and the application of functional nucleic acid-enhancing materials.

Self-assembling biomolecules for biosensor applications

Molecular self-assembly has received considerable attention in biomedical fields as a simple and effective method for developing biomolecular nanostructures. Self-assembled nanostructures can exhibit high binding affinity and selectivity by displaying multiple ligands/receptors on their surface. In addition, the use of supramolecular structure change upon binding is an intriguing approach to generate binding signal. Therefore, many self-assembled nanostructure-based biosensors have been developed over the past decades, using various biomolecules (e.g., peptides, DNA, RNA, lipids) and their combinations with non-biological substances. In this review, we provide an overview of recent developments in the design and fabrication of self-assembling biomolecules for biosensing. Furthermore, we discuss representative electrochemical biosensing platforms which convert the biochemical reactions of those biomolecules into electrical signals (e.g., voltage, ampere, potential difference, impedance) to contribute to detect targets. This paper also highlights the successful outcomes of self-assembling biomolecules in biosensor applications and discusses the challenges that this promising technology needs to overcome for more widespread use.

Peptide Amphiphilic Supramolecular Nanogels: Competent Host for Notably Efficient Lipase-Catalyzed Hydrolysis of Water-Insoluble Substrates

The present work depicts the development of stable nanogels in an aqueous medium that were exploited for efficient surface-active lipase-catalyzed hydrolysis of water-insoluble substrates. Surfactant-coated gel nanoparticles (neutral NG1, anionic NG2, and cationic NG3) were prepared from peptide amphiphilic hydrogelator (G1, G2, and G3, respectively) at different hydrophilic and lipophilic balance (HLB). Chromobacterium viscosum (CV) lipase activity towards hydrolysis of water-insoluble substrates (p-nitrophyenyl-n-alkanoates (C4-C10)) in the presence of nanogels got remarkably improved by ~1.7-8.0 fold in comparison to that in aqueous buffer and other self-aggregates. An increase in hydrophobicity of the substrate led to a notable improvement in lipase activity in the hydrophilic domain (HLB>8.0) of nanogels. The micro-heterogeneous interface of small-sized (10-65 nm) nanogel was found to be an appropriate scaffold for immobilizing surface-active lipase to exhibit superior catalytic efficiency. Concurrently, the flexible conformation of lipase immobilized in nanogels was reflected in its secondary structure having the highest α-helix content from the circular dichroism spectra.

Current perspectives and trends in nanoparticle drug delivery systems in breast cancer: bibliometric analysis and review

The treatment of breast cancer (BC) is a serious challenge due to its heterogeneous nature, multidrug resistance (MDR), and limited therapeutic options. Nanoparticle-based drug delivery systems (NDDSs) represent a promising tool for overcoming toxicity and chemotherapy drug resistance in BC treatment. No bibliometric studies have yet been published on the research landscape of NDDS-based treatment of BC. In this review, we extracted data from 1,752 articles on NDDS-based treatment of BC published between 2012 and 2022 from the Web of Science Core Collection (WOSCC) database. VOSviewer, CiteSpace, and some online platforms were used for bibliometric analysis and visualization. Publication trends were initially observed: in terms of geographical distribution, China and the United States had the most papers on this subject. The highest contributing institution was Sichuan University. In terms of authorship and co-cited authorship, the most prolific author was Yu Zhang. Furthermore, Qiang Zhang and co-workers have made tremendous achievements in the field of NDDS-based BC treatment. The article titled "Nanomedicine in cancer therapy: challenges, opportunities, and clinical applications" had the most citations. The Journal of Controlled Release was one of the most active publishers in the field. "Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries" was the most cited reference. We also analysed "hot" and cutting-edge research for NDDSs in BC treatment. There were nine topic clusters: "tumour microenvironment," "nanoparticles (drug delivery)," "breast cancer/triple-negative breast cancer," "combination therapy," "drug release (pathway)," "multidrug resistance," "recent advance," "targeted drug delivery", and "cancer nanomedicine." We also reviewed the core themes of research. In summary, this article reviewed the application of NDDSs in the treatment of BC.

Recent Advances in Messenger Ribonucleic Acid (mRNA) Vaccines and Their Delivery Systems: A Review

Messenger ribonucleic acid (mRNA) was found as the intermediary that transfers genetic information from DNA to ribosomes for protein synthesis in 1961. The emergency use authorization of the two covid-19 mRNA vaccines, BNT162b2 and mRNA-1273, is a significant achievement in the history of vaccine development. Because they are generated in a cell-free environment using the in vitro transcription (IVT) process, mRNA vaccines are risk-free. Moreover, chemical modifications to the mRNA molecule, such as cap structures and changed nucleosides, have proved critical in overcoming immunogenicity concerns, achieving sustained stability, and achieving effective, accurate protein production in vivo. Several vaccine delivery strategies (including protamine, lipid nanoparticles (LNPs), polymers, nanoemulsions, and cell-based administration) were also optimized to load and transport RNA into the cytosol. LNPs, which are composed of a cationic or a pH-dependent ionizable lipid layer, a polyethylene glycol (PEG) component, phospholipids, and cholesterol, are the most advanced systems for delivering mRNA vaccines. Moreover, modifications of the four components that make up the LNPs showed to increase vaccine effectiveness and reduce side effects. Furthermore, the introduction of biodegradable lipids improved LNP biocompatibility. Furthermore, mRNA-based therapies are expected to be effective treatments for a variety of refractory conditions, including infectious diseases, metabolic genetic diseases, cancer, cardiovascular and cerebrovascular diseases. Therefore, the present review aims to provide the scientific community with up-to-date information on mRNA vaccines and their delivery systems.

Protective Effects of a Jellyfish-Derived Thioredoxin Fused with Cell-Penetrating Peptide TAT-PTD on H2O2-Induced Oxidative Damage

Thioredoxin (Trx) plays a critical role in maintaining redox balance in various cells and exhibits anti-oxidative, anti-apoptotic, and anti-inflammatory effects. However, whether exogenous Trx can inhibit intracellular oxidative damage has not been investigated. In previous study, we have identified a novel Trx from the jellyfish Cyanea capillata, named CcTrx1, and confirmed its antioxidant activities in vitro. Here, we obtained a recombinant protein, PTD-CcTrx1, which is a fusion of CcTrx1 and protein transduction domain (PTD) of HIV TAT protein. The transmembrane ability and antioxidant activities of PTD-CcTrx1, and its protective effects against H₂O₂-induced oxidative damage in HaCaT cells were also detected. Our results revealed that PTD-CcTrx1 exhibited specific transmembrane ability and antioxidant activities, and it could significantly attenuate the intracellular oxidative stress, inhibit H₂O₂-induced apoptosis, and protect HaCaT cells from oxidative damage. The present study provides critical evidence for application of PTD-CcTrx1 as a novel antioxidant to treat skin oxidative damage in the future.

Tuning dynamic DNA- and peptide-driven self-assembly in DNA-peptide conjugates

DNA-peptide conjugates offer an opportunity to marry the benefits of both biomolecular classes, combining the high level of programmability found with DNA, with the chemical diversity of peptides. These hybrid systems offer potential in fields such as therapeutics, nanotechnology, and robotics. Using the first DNA-β-turn peptide conjugate, we present three studies investigating the self-assembly of DNA-peptide conjugates over a period of 28 days. Time-course studies, such as these have not been previously conducted for DNA-peptide conjugates, although they are common in pure peptide assembly, for example in amyloid research. By using aging studies to assess the structures produced, we gain insights into the dynamic nature of these systems. The first study explores the influence varying amounts of DNA-peptide conjugates have on the self-assembly of our parent peptide. Study 2 explores how DNA and peptide can work together to change the structures observed during aging. Study 3 investigates the presence of orthogonality within our system by switching the DNA and peptide control on and off independently. These results show that two orthogonal self-assemblies can be combined and operated independently or in tandem within a single macromolecule, with both spatial and temporal effects upon the resultant nanostructures.

siRNA Functionalized Lipid Nanoparticles (LNPs) in Management of Diseases

RNAi (RNA interference)-based technology is emerging as a versatile tool which has been widely utilized in the treatment of various diseases. siRNA can alter gene expression by binding to the target mRNA and thereby inhibiting its translation. This remarkable potential of siRNA makes it a useful candidate, and it has been successively used in the treatment of diseases, including cancer. However, certain properties of siRNA such as its large size and susceptibility to degradation by RNases are major drawbacks of using this technology at the broader scale. To overcome these challenges, there is a requirement for versatile tools for safe and efficient delivery of siRNA to its target site. Lipid nanoparticles (LNPs) have been extensively explored to this end, and this paper reviews different types of LNPs, namely liposomes, solid lipid NPs, nanostructured lipid carriers, and nanoemulsions, to highlight this delivery mode. The materials and methods of preparation of the LNPs have been described here, and pertinent physicochemical properties such as particle size, surface charge, surface modifications, and PEGylation in enhancing the delivery performance (stability and specificity) have been summarized. We have discussed in detail various challenges facing LNPs and various strategies to overcome biological barriers to undertake the safe delivery of siRNA to a target site. We additionally highlighted representative therapeutic applications of LNP formulations with siRNA that may offer unique therapeutic benefits in such wide areas as acute myeloid leukaemia, breast cancer, liver disease, hepatitis B and COVID-19 as recent examples.

An assembly-inducing PDC enabling the efficient nuclear delivery of nucleic acid for cancer stem-like cell suppression

Nucleic acid therapy is attracting great attention in diverse clinical translations because of its therapeutic advantages. As a renowned oligonucleotide therapeutical candidate in the clinical stage, AS1411 has shown outstanding tumor suppressing effects; however, its efficient delivery to the cell nucleus is critical for its anticancer effect. Herein, we identified a multifunctional peptide drug conjugate (PDC) as a safe and efficient carrier to achieve the nuclear delivery of AS1411. This PDC consists of the cell penetration peptide RW9, an HDAC inhibitor warhead (peptide C-terminus), and 5-FU (peptide N-terminus), which can coassemble with AS1411 to form nanospheres. The PDC efficiently delivered AS1411 to the nucleus of several types of cancer cells. Moreover, it reversed the stemness of a cancer stem-like cell line. Significantly, due to the assembly-induced accumulation enhancement and retention, a safe single agent concentration of PDC showed unexpected synergy with AS1411 to augment the cancer cell suppression efficiency, exemplified by the downregulation of the stemness-related proteins and the upregulation of apoptosis-related proteins. Therefore, our work presents a powerful strategy for the nuclear delivery of nucleic acid drugs by leveraging cancer-suppressing PDC as assembly inducers, which provides a powerful combination regimen in treating cancer stem-like cells.

Nanotechnology Advances in the Detection and Treatment of Cancer: An Overview

Over the last few years, progress has been made across the nanomedicine landscape, in particular, the invention of contemporary nanostructures for cancer diagnosis and overcoming complexities in the clinical treatment of cancerous tissues. Thanks to their small diameter and large surface-to-volume proportions, nanomaterials have special physicochemical properties that empower them to bind, absorb and transport high-efficiency substances, such as small molecular drugs, DNA, proteins, RNAs, and probes. They also have excellent durability, high carrier potential, the ability to integrate both hydrophobic and hydrophilic compounds, and compatibility with various transport routes, making them especially appealing over a wide range of oncology fields. This is also due to their configurable scale, structure, and surface properties. This review paper discusses how nanostructures can function as therapeutic vectors to enhance the therapeutic value of molecules; how nanomaterials can be used as medicinal products in gene therapy, photodynamics, and thermal treatment; and finally, the application of nanomaterials in the form of molecular imaging agents to diagnose and map tumor growth.

Engineering of small-molecule lipidic prodrugs as novel nanomedicines for enhanced drug delivery

A widely established prodrug strategy can effectively optimize the unappealing properties of therapeutic agents in cancer treatment. Among them, lipidic prodrugs extremely uplift the physicochemical properties, site-specificity, and antitumor activities of therapeutic agents while reducing systemic toxicity. Although great perspectives have been summarized in the progress of prodrug-based nanoplatforms, no attention has been paid to emphasizing the rational design of small-molecule lipidic prodrugs (SLPs). With the aim of outlining the prospect of the SLPs approach, the review will first provide an overview of conjugation strategies that are amenable to SLPs fabrication. Then, the rational design of SLPs in response to the physiological barriers of chemotherapeutic agents is highlighted. Finally, their biomedical applications are also emphasized with special functions, followed by a brief introduction of the promising opportunities and potential challenges of SLPs-based drug delivery systems (DDSs) in clinical application.

Graphical Abstract

RNA Drug Delivery Using Biogenic Nanovehicles for Cancer Therapy

RNA-based therapies have been promising method for treating all kinds of diseases, and four siRNA-based drugs and two mRNA-based drugs have been approved and are on the market now. However, none of them is applied for cancer treatment. This is not only because of the complexity of the tumor microenvironment, but also due to the intrinsic obstacles of RNAs. Until now, all kinds of strategies have been developed to improve the performance of RNAs for cancer therapy, especially the nanoparticle-based ones using biogenic materials. They are much more compatible with less toxicity compared to the ones using synthetic polymers, and the most widely studied biogenic materials are oligonucleotides, exosomes, and cell membranes. Particular characteristics make them show different capacities in internalization and endosomal escape as well as specific targeting. In this paper, we systematically summarize the RNA-based nano-delivery systems using biogenic materials for cancer therapy, and we believe this review will provide a valuable reference for researchers involved in the field of biogenic delivery and RNA-based therapies for cancer treatment.

A Rapid Self-Assembly Peptide Hydrogel for Recruitment and Activation of Immune Cells

Self-assembly peptide nanotechnology has attracted much attention due to its regular and orderly structure and diverse functions. Most of the existing self-assembly peptides can form aggregates with specific structures only under specific conditions and their assembly time is relatively long. They have good biocompatibility but no immunogenicity. To optimize it, a self-assembly peptide named DRF3 was designed. It contains a hydrophilic and hydrophobic surface, using two N-terminal arginines, leucine, and two c-terminal aspartate and glutamic acid. Meanwhile, the c-terminal of the peptide was amidated, so that peptide segments were interconnected to increase diversity. Its characterization, biocompatibility, controlled release effect on antigen, immune cell recruitment ability, and antitumor properties were examined here. Congo red/aniline blue staining revealed that peptide hydrogel DRF3 could be immediately gelled in PBS. The stable β-sheet secondary structure of DRF3 was confirmed by circular dichroism spectrum and IR spectra. The observation results of cryo-scanning electron microscopy, transmission electron microscopy, and atomic force microscopy demonstrated that DRF3 formed nanotubule-like and vesicular structures in PBS, and these structures interlaced with each other to form ordered three-dimensional nanofiber structures. Meanwhile, DRF3 showed excellent biocompatibility, could sustainably and slowly release antigens, recruit dendritic cells and promote the maturation of dendritic cells (DCs) in vitro. In addition, DRF3 has a strong inhibitory effect on clear renal cell carcinoma (786-0). These results provide a reliable basis for the application of peptide hydrogels in biomedical and preclinical trials.

Microneedle systems for delivering nucleic acid drugs

Background

Nucleic acid-based gene therapy is a promising technology that has been used in various applications such as novel vaccination platforms for infectious/cancer diseases and cellular reprogramming because of its fast, specific, and effective properties. Despite its potential, the parenteral nucleic acid drug formulation exhibits instability and low efficacy due to various barriers, such as stability concerns related to its liquid state formulation, skin barriers, and endogenous nuclease degradation. As promising alternatives, many attempts have been made to perform nucleic acid delivery using a microneedle system. With its minimal invasiveness, microneedle can deliver nucleic acid drugs with enhanced efficacy and improved stability.

Area covered

This review describes nucleic acid medicines' current state and features and their delivery systems utilizing non-viral vectors and physical delivery systems. In addition, different types of microneedle delivery systems and their properties are briefly reviewed. Furthermore, recent advances of microneedle-based nucleic acid drugs, including featured vaccination applications, are described.

Expert opinion

Nucleic acid drugs have shown significant potential beyond the limitation of conventional small molecules, and the current COVID-19 pandemic highlights the importance of nucleic acid therapies as a novel vaccination platform. Microneedle-mediated nucleic acid drug delivery is a potential platform for less invasive nucleic acid drug delivery. Microneedle system can show enhanced efficacy, stability, and improved patient convenience through self-administration with less pain.

Supramolecular biomaterials for bio-imaging and imaging-guided therapy

Benefiting from their unique advantages, including reversibly switchable structures, good biocompatibility, facile functionalization, and sensitive response to biological stimuli, supramolecular biomaterials have been widely applied in biomedicine. In this review, the representative achievements and trends in the design of supramolecular biomaterials (mainly those derived from biomacromolecules) with specific macromolecules including peptides, deoxyribonucleic acid, and polysaccharides, as well as their applications in bio-imaging and imaging-guided therapy are summarized. This review will serve as an important summary and "go for" reference for explorations of the applications of supramolecular biomaterials in bio-imaging and image-guided therapy, and will promote the development of supramolecular chemistry as an emerging interdisciplinary research area.

Expanding the chemical functionality of DNA nanomaterials generated by rolling circle amplification

Rolling circle amplification (RCA) is a powerful tool for the construction of DNA nanomaterials such as hydrogels, high-performance scaffolds and DNA nanoflowers (DNFs), hybrid materials formed of DNA and magnesium pyrophosphate. Such DNA nanomaterials have great potential in therapeutics, imaging, protein immobilisation, and drug delivery, yet limited chemistry is available to expand their functionality. Here, we present orthogonal strategies to produce densely modified RCA products and DNFs. We provide methods to selectively modify the DNA component and/or the protein cargo of these materials, thereby greatly expanding the range of chemical functionalities available to these systems. We have used our methodology to construct DNFs bearing multiple surface aptamers and peptides capable of binding to cancer cells that overexpress the HER2 oncobiomarker, demonstrating their potential for diagnostic and therapeutic applications.

Nanovaccines against Animal Pathogens: The Latest Findings

Nowadays, safe and efficacious vaccines represent powerful and cost-effective tools for global health and economic growth. In the veterinary field, these are undoubtedly key tools for improving productivity and fighting zoonoses. However, cases of persistent infections, rapidly evolving pathogens having high variability or emerging/re-emerging pathogens for which no effective vaccines have been developed point out the continuing need for new vaccine alternatives to control outbreaks. Most licensed vaccines have been successfully used for many years now; however, they have intrinsic limitations, such as variable efficacy, adverse effects, and some shortcomings. More effective adjuvants and novel delivery systems may foster real vaccine effectiveness and timely implementation. Emerging vaccine technologies involving nanoparticles such as self-assembling proteins, virus-like particles, liposomes, virosomes, and polymeric nanoparticles offer novel, safe, and high-potential approaches to address many vaccine development-related challenges. Nanotechnology is accelerating the evolution of vaccines because nanomaterials having encapsulation ability and very advantageous properties due to their size and surface area serve as effective vehicles for antigen delivery and immunostimulatory agents. This review discusses the requirements for an effective, broad-coverage-elicited immune response, the main nanoplatforms for producing it, and the latest nanovaccine applications for fighting animal pathogens.

Illuminating endosomal escape of polymorphic lipid nanoparticles that boost mRNA delivery

Lipid-based nanoparticles (LNPs) for the delivery of mRNA have jumped to the forefront of non-viral gene delivery. Despite this exciting development, poor endosomal escape after LNP cell entry remains an unsolved, rate-limiting bottleneck. Here we report the use of a galectin 8-GFP (Gal8-GFP) cell reporter system to visualize the endosomal escape capabilities of LNP-encapsulated mRNA. LNPs substituted with phytosterols in place of cholesterol exhibited various levels of Gal8 recruitment in the Gal8-GFP reporter system. In live-cell imaging, LNPs containing β-sitosterol (LNP-Sito) showed a 10-fold increase in detectable endosomal perturbation events when compared to the standard cholesterol LNPs (LNP-Chol), suggesting the superior capability of LNP-Sito to escape from endosomal entrapment. Trafficking studies of these LNPs showed strong localization with late endosomes. This highly sensitive and robust Gal8-GFP reporter system can be a valuable tool to elucidate intricacies of LNP trafficking and ephemeral endosomal escape events, enabling advancements in gene delivery.

Emerging trends of receptor-mediated tumor targeting peptides: A review with perspective from molecular imaging modalities

Natural peptides extracted from natural components such are known to have a relatively short in-vivo half-life and can readily metabolize by endo- and exo-peptidases. Fortunately, synthetic peptides can be easily manipulated to increase in-vivo stability, membrane permeability and target specificity with some well-known natural families. Many natural as well as synthetic peptides target to their endogenous receptors for diagnosis and therapeutic applications. In order to detect these peptides externally, they must be modified with radionuclides compatible with single photon emission computed tomography (SPECT) or positron emission tomography (PET). Although, these techniques mainly rely on physiological changes and have profound diagnostic strength over anatomical modalities such as MRI and CT. However, both SPECT and PET observed to possess lack of anatomical reference frame which is a key weakness of these techniques, and unfortunately, cannot be available freely in most clinical centres especially in under-developing countries. Hence, it is need of the time to design and develop economic, patient friendly and versatile strategies to grapple with existing problems without any hazardous side effects. Optical molecular imaging (OMI) has emerged as a novel technique in field of medical science using fluorescent probes as imaging modality and has ability to couple with organic drugs, small molecules, chemotherapeutics, DNA, RNA, anticancer peptide and protein without adding chelators as necessary for radionuclides. Furthermore, this review focuses on difference in imaging modalities and provides ample knowledge about reliable, economic and patient friendly optical imaging technique rather radionuclide-based imaging techniques.

Self-assembled mRNA vaccines

mRNA vaccines have evolved from being a mere curiosity to emerging as COVID-19 vaccine front-runners. Recent advancements in the field of RNA technology, vaccinology, and nanotechnology have generated interest in delivering safe and effective mRNA therapeutics. In this review, we discuss design and self-assembly of mRNA vaccines. Self-assembly, a spontaneous organization of individual molecules, allows for design of nanoparticles with customizable properties. We highlight the materials commonly utilized to deliver mRNA, their physicochemical characteristics, and other relevant considerations, such as mRNA optimization, routes of administration, cellular fate, and immune activation, that are important for successful mRNA vaccination. We also examine the COVID-19 mRNA vaccines currently in clinical trials. mRNA vaccines are ready for the clinic, showing tremendous promise in the COVID-19 vaccine race, and have pushed the boundaries of gene therapy.

Harnessing Endogenous Stimuli for Responsive Materials in Theranostics

Materials that respond to endogenous stimuli are being leveraged to enhance spatiotemporal control in a range of biomedical applications from drug delivery to diagnostic tools. The design of materials that undergo morphological or chemical changes in response to specific biological cues or pathologies will be an important area of research for improving efficacies of existing therapies and imaging agents, while also being promising for developing personalized theranostic systems. Internal stimuli-responsive systems can be engineered across length scales from nanometers to macroscopic and can respond to endogenous signals such as enzymes, pH, glucose, ATP, hypoxia, redox signals, and nucleic acids by incorporating synthetic bio-inspired moieties or natural building blocks. This Review will summarize response mechanisms and fabrication strategies used in internal stimuli-responsive materials with a focus on drug delivery and imaging for a broad range of pathologies, including cancer, diabetes, vascular disorders, inflammation, and microbial infections. We will also discuss observed challenges, future research directions, and clinical translation aspects of these responsive materials.

Supramolecular cancer nanotheranostics

Among the many challenges in medicine, the treatment and cure of cancer remains an outstanding goal given the complexity and diversity of the disease. Nanotheranostics, the integration of therapy and diagnosis in nanoformulations, is the next generation of personalized medicine to meet the challenges in precise cancer diagnosis, rational management and effective therapy, aiming to significantly increase the survival rate and improve the life quality of cancer patients. Different from most conventional platforms with unsatisfactory theranostic capabilities, supramolecular cancer nanotheranostics have unparalleled advantages in early-stage diagnosis and personal therapy, showing promising potential in clinical translations and applications. In this review, we summarize the progress of supramolecular cancer nanotheranostics and provide guidance for designing new targeted supramolecular theranostic agents. Based on extensive state-of-the-art research, our review will provide the existing and new researchers a foundation from which to advance supramolecular cancer nanotheranostics and promote translationally clinical applications.

Polyamine-Functionalized 2'-Amino-LNA in Oligonucleotides: Facile Synthesis of New Monomers and High-Affinity Binding towards ssDNA and dsDNA

Attachment of cationic moieties to oligonucleotides (ONs) promises not only to increase the binding affinity of antisense ONs by reducing charge repulsion between the two negatively charged strands of a duplex, but also to augment their in vivo stability against nucleases. In this study, polyamine functionality was introduced into ONs by means of 2'-amino-LNA scaffolds. The resulting ONs exhibited efficient binding towards ssDNA, ssRNA and dsDNA targets, and the 2'-amino-LNA analogue carrying a triaminated linker showed the most pronounced duplex- and triplex-stabilizing effect. Molecular modelling revealed that favourable conformational and electrostatic effects led to salt-bridge formation between positively charged polyamine moieties and the Watson-Hoogsteen groove of the dsDNA targets, resulting in the observed triplex stabilization. All the investigated monomers showed increased resistance against 3'-nucleolytic digestion relative to the non-functionalized controls.

Supramolecular Self-Assembled Peptide-Based Vaccines: Current State and Future Perspectives

Despite the undeniable success of vaccination programs in preventing diseases, effective vaccines against several life-threatening infectious pathogens such as human immunodeficiency virus are still unavailable. Vaccines are designed to boost the body's natural ability to protect itself against foreign pathogens. To enhance vaccine-based immunotherapies to combat infections, cancer, and other conditions, biomaterials have been harnessed to improve vaccine safety and efficacy. Recently, peptides engineered to self-assemble into specific nanoarchitectures have shown great potential as advanced biomaterials for vaccine development. These supramolecular nanostructures (i.e., composed of many peptides) can be programmed to organize into various forms, including nanofibers, nanotubes, nanoribbons, and hydrogels. Additionally, they have been designed to be responsive upon exposure to various external stimuli, providing new innovations in the development of smart materials for vaccine delivery and immunostimulation. Specifically, self-assembled peptides can provide cell adhesion sites, epitope recognition, and antigen presentation, depending on their biochemical and structural characteristics. Furthermore, they have been tailored to form exquisite nanostructures that provide improved enzymatic stability and biocompatibility, in addition to the controlled release and targeted delivery of immunomodulatory factors (e.g., adjuvants). In this mini review, we first describe the different types of self-assembled peptides and resulting nanostructures that have recently been investigated. Then, we discuss the recent progress and development trends of self-assembled peptide-based vaccines, their challenges, and clinical translatability, as well as their future perspectives.

In situ tumor-triggered subcellular precise delivery of multi-drugs for enhanced chemo-photothermal-starvation combination antitumor therapy

Rationale: Drug combination therapy for cancer treatment exerts a more potent antitumor effect. The targeted delivery and release of multiple drugs in a patient's body thus presents a more effective treatment approach, warranting further research. Methods: Two antitumor drugs (ICG: indocyanine green and THP: pirarubicin) were successfully screened to sequentially trigger self-assembling peptides (P60) to produce bacteria-sized particles (500-1000 nm, P60-ICG-THP). First, after mixing equal amount of P60 and ICG, trace amount of water (the mass ratio between P60 and water: 100:1) was used to trigger their assembly into P60-ICG. Subsequently, the assembly of P60-ICG and THP was further triggered by ultrasound treatment to produce P60-ICG-THP. Results: P60-ICG-THP constituted a cluster of several nanoparticles (50-100 nm) and possessed a negative charge. Owing to its size and charge characteristics, P60-ICG-THP could remain outside the cell membrane, avoiding the phagocytic clearance of blood and normal tissue cells in vivo. However, after localizing in the tumor, the size and charge switches of P60-ICG-THP, rapidly triggered by the low pH of the tumor microenvironment, caused P60-ICG-THP to segregate into two parts: (i) positively charged nanoparticles with a size of approximately 50 nm, and (ii) negatively charged particles of an uneven size. The former, mainly carrying THP (chemotherapeutic agent), could immediately cross the cell membrane and deliver pirarubicin into the nucleus of tumor cells. The latter, carrying ICG (used for photothermal therapy), could also enter the cell via the endocytosis pathway or accumulate in tumor blood vessels to selectively block the supply of nutrients and oxygen (cancer starvation). Both these particles could avoid the rapid excretion of ICG in the liver and were conducive to accumulation in the tumor tissue for photothermal therapy. Conclusion: Our drug delivery system not only achieves the precise subcellular delivery of two anticancer drugs due to their size and charge switches in the tumor site, but also provides a new strategy to combine chemotherapy, photothermal therapy, and cancer starvation therapy for the development of a highly efficient antitumor therapeutic regimen.

Demonstration of intracellular trafficking, cytosolic bioavailability, and target manipulation of an antibody delivery platform

Intracellular antibody delivery into live cells has significant implications for research and therapeutic applications. However, many delivery systems lack potency due to low uptake and/or endosomal entrapment and understanding of intracellular delivery processes is lacking. Herein, we studied the cellular uptake, intracellular trafficking and targeting of antibodies using our previously developed Hex antibody nanocarrier. We demonstrated Hex-antibodies were internalized through multiple endocytic routes into lysosomes and provide evidence of endo/lysosomal disruption and Hex-antibody release to the cytosol. Cytosolic antibodies retained their bioactivity for at least 24 h. Functional effect of Hex delivered anti-STAT3 antibodies was evidenced by inhibition of nuclear translocation of cytosolic transcription factor STAT3. This study has generated understanding of key steps in the Hex intracellular antibody delivery system and will facilitate the development of effective cytosolic antibody delivery and applications in both the therapeutic and research domains.

Medical Applications Based on Supramolecular Self-Assembled Materials From Tannic Acid

Polyphenol, characterized by various phenolic rings in the chemical structure and an abundance in nature, can be extracted from vegetables, grains, chocolates, fruits, tea, legumes, and seeds, among other sources. Tannic acid (TA), a classical polyphenol with a specific chemical structure, has been widely used in biomedicine because of its outstanding biocompatibility and antibacterial and antioxidant properties. TA has tunable interactions with various materials that are widely distributed in the body, such as proteins, polysaccharides, and glycoproteins, through multimodes including hydrogen bonding, hydrophobic interactions, and charge interactions, assisting TA as important building blocks in the supramolecular self-assembled materials. This review summarizes the recent immense progress in supramolecular self-assembled materials using TA as building blocks to generate different materials such as hydrogels, nanoparticles/microparticles, hollow capsules, and coating films, with enormous potential medical applications including drug delivery, tumor diagnosis and treatment, bone tissue engineering, biofunctional membrane material, and the treatment of certain diseases. Furthermore, we discuss the challenges and developmental prospects of supramolecular self-assembly nanomaterials based on TA.

Naturally Derived Membrane Lipids Impact Nanoparticle-Based Messenger RNA Delivery

Introduction

Lipid based nanoparticles (LNPs) are clinically successful vectors for hepatic delivery of nucleic acids. These systems are being developed for non-hepatic delivery of mRNA for the treatment of diseases like cystic fibrosis or retinal degeneration as well as infectious diseases. Localized delivery to the lungs requires aerosolization. We hypothesized that structural lipids within LNPs would provide features of integrity which can be tuned for attributes required for efficient hepatic and non-hepatic gene delivery. Herein, we explored whether naturally occurring lipids that originate from the cell membrane of plants and microorganisms enhance mRNA-based gene transfection in vitro and in vivo and whether they assist in maintaining mRNA activity after nebulization.

Methods

We substituted DSPC, a structural lipid used in a conventional LNP formulation, to a series of naturally occurring membrane lipids. We measured the effect of these membrane lipids on size, encapsulation efficiency and their impact on transfection efficiency. We further characterized LNPs after nebulization and measured whether they retained their transfection efficiency.

Results

One plant-derived structural lipid, DGTS, led to a significant improvement in liver transfection of mRNA. DGTS LNPs had similar transfection ability when administered in the nasal cavity to conventional LNPs. In contrast, we found that DGTS LNPs had reduced transfection efficiency in cells pre-and post-nebulization while maintaining size and encapsulation similar to DSPC LNPs.

Conclusions

We found that structural lipids provide differential mRNA-based activities in vitro and in vivo which also depend on the mode of administration. Understanding influence of structural lipids on nanoparticle morphology and structure can lead to engineering potent materials for mRNA-based gene therapy applications.

Nanoscale Self-Assembly for Therapeutic Delivery

Self-assembly is the process of association of individual units of a material into highly arranged/ordered structures/patterns. It imparts unique properties to both inorganic and organic structures, so generated, via non-covalent interactions. Currently, self-assembled nanomaterials are finding a wide variety of applications in the area of nanotechnology, imaging techniques, biosensors, biomedical sciences, etc., due to its simplicity, spontaneity, scalability, versatility, and inexpensiveness. Self-assembly of amphiphiles into nanostructures (micelles, vesicles, and hydrogels) happens due to various physical interactions. Recent advancements in the area of drug delivery have opened up newer avenues to develop novel drug delivery systems (DDSs) and self-assembled nanostructures have shown their tremendous potential to be used as facile and efficient materials for this purpose. The main objective of the projected review is to provide readers a concise and straightforward knowledge of basic concepts of supramolecular self-assembly process and how these highly functionalized and efficient nanomaterials can be useful in biomedical applications. Approaches for the self-assembly have been discussed for the fabrication of nanostructures. Advantages and limitations of these systems along with the parameters that are to be taken into consideration while designing a therapeutic delivery vehicle have also been outlined. In this review, various macro- and small-molecule-based systems have been elaborated. Besides, a section on DNA nanostructures as intelligent materials for future applications is also included.

Synthesis and applications of theranostic oligonucleotides carrying multiple fluorine atoms

The use of various oligonucleotide (ON) syntheses and post-synthetic strategies for targeted chemical modification enables improving their efficacy as potent modulators of gene expression levels in eukaryotic cells. However, the search still continues for new approaches designed for increasing internalization, lysosomal escape, and tissue specific delivery of ON. In this review we emphasized all aspects related to the synthesis and properties of ON derivatives carrying multifluorinated (MF) groups. These MF groups have unique physico-chemical properties because of their simultaneous hydrophobicity and lipophobicity. Such unusual combination of properties results in the overall modification of ON mode of interaction with the cells and making multi-fluorination highly relevant to the goal of improving potency of ON as components of new therapies. The accumulated evidence so far is pointing to high potential of ON probes, RNAi components and ON imaging beacons carrying single or multiple MF groups for improving the stability, specificity of interaction with biological targets and delivery of ONs in vitro and potentially in vivo.

Chimeric peptide supramolecular nanoparticles for plectin-1 targeted miRNA-9 delivery in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease with poor prognosis. Insights into the roles of MicroRNAs (miRNAs) in diseases, particularly in cancer, have made miRNAs attractive tools and targets for novel therapeutic approaches. Methods: Here, we employed a novel chimeric peptide supramolecular nanoparticle delivery system for plectin-1 (PL-1)-targeted PDAC-specific miR-9 delivery in vitro and in pancreatic cancer patient-derived xenograft (PDX) model. RT-PCR and immunohistochemistry (IHC) were conducted to detect the expression pattern of eIF5A2. mRFP-GFP-LC3 fluorescence microscopy and Western blot were carried out to determine autophagy. Luciferase reporter assays were performed to elucidate the regulatory role of miR-9/eIF5A2 axis. Results: PL-1/miR-9 nanocomplexes dramatically improve the anticancer effect of doxorubicin through downregulating eIF5A2 expression to inhibit autophagy and induce apoptosis in PDAC therapy in vivo. Mechanistically, miR-9 directly targets the eIF5A2 transcript by binding to its 3'-untranslated region (3'-UTR) to reduce the expression levels and the secreted protein of eIF5A2 in PDAC cells. Conclusion: PL-1/miR-9 nanoparticles can be used as a novel promising anti-cancer strategy with tumor targeting and miR-9/eIF5A2 may serve as a new potential therapeutic target for future synergic therapy against human PDAC.

Supramolecular Nanotheranostics

This supramolecular nanotheranostics special issue collected a total of 17 review articles and 3 research articles broadly covering the current and emerging supramolecular nanotheranostics.

Brief update on endocytosis of nanomedicines

The complexity of nanoscale interactions between biomaterials and cells has limited the realization of the ultimate vision of nanotechnology in diagnostics and therapeutics. As such, significant effort has been devoted to advancing our understanding of the biophysical interactions of the myriad nanoparticles. Endocytosis of nanomedicine has drawn tremendous interest in the last decade. Here, we highlight the ever-present barriers to efficient intracellular delivery of nanoparticles as well as the current advances and strategies deployed to breach these barriers. We also introduce new barriers that have been largely overlooked such as the glycocalyx and macromolecular crowding. Additionally, we draw attention to the potential complications arising from the disruption of the newly discovered functions of the lysosomes. Novel strategies of exploiting the inherent intracellular defects in disease states to enhance delivery and the use of exosomes for bioanalytics and drug delivery are explored. Furthermore, we discuss the advances in imaging techniques like electron microscopy, super resolution fluorescence microscopy, and single particle tracking which have been instrumental in our growing understanding of intracellular pathways and nanoparticle trafficking. Finally, we advocate for the push towards more intravital analysis of nanoparticle transport phenomena using the multitude of techniques available to us. Unraveling the underlying mechanisms governing the cellular barriers to delivery and biological interactions of nanoparticles will guide the innovations capable of breaching these barriers.