Applications of Spherical Nucleic Acid Nanoparticles as Delivery Systems

Poly-T-Modified Gold Nanorods Suppress Macrophage-Mediated Inflammation for Periodontitis Therapy

Traditional treatments for periodontitis are limited by their inability to adequately modulate the immune response and control inflammation. Recently, nucleic acid-modified nanomaterials have attracted significant attention for their potential in regulating inflammation. Among these, most nanomaterials, such as spherical nucleic acids, tend to exhibit pro-inflammatory effects. In this study, we identified for the first time that poly-T sequence-modified gold nanorods (PTM AuNRs) possess significant anti-inflammatory properties. The PTM AuNRs demonstrated excellent biocompatibility and efficacy in treating ligation-induced periodontitis. PTM AuNRs modulate immune responses by inhibiting the differentiation of pro-inflammatory M1 macrophages and reducing pro-inflammatory cytokine levels through promoting AMPK activation. When administered via local injection, PTM AuNRs effectively suppress inflammatory response and inflammatory cell infiltration, downregulate inflammatory cytokine levels, and mitigate collagen fiber degradation and alveolar bone loss. Together, these findings highlight PTM AuNRs as a promising and innovative therapeutic strategy for periodontitis management.

Improvement of carboplatin chemosensitivity in lung cancer cells by siRNA-mediated downregulation of DLGAP1-AS2 expression

Despite being one of the primary and most effective treatments for advanced stages of lung cancer, chemotherapy drugs like carboplatin have limitations due to their adverse side effects and the development of drug resistance in lung cancer cells. However, recent studies have shown promising results in using small interfering RNAs (siRNAs) as a therapeutic agent for cancer treatment. Hence, this study aimed to investigate the potential of combining siRNA-DLGAP1-AS2 with carboplatin in human lung cancer cell lines. The viability of the cells was assessed using the MTT assay, and apoptosis induction was examined through Annexin V/Pi staining. Additionally, the effect of the combination on cell cycle arrest and colony formation of lung cancer cells was studied. Furthermore, the expression of Bax, Bcl-2, MMP-2, MMP-9, GCLC, and CD44 was evaluated. Our functional analysis revealed that inhibiting the expression of DLGAP1-AS2 increased the sensitivity of lung cancer cells to carboplatin. Moreover, our study demonstrated that the combination of DLGAP1-AS2 inhibition through siRNA-DLGAP1-AS2 transfection and carboplatin treatment had a tumor-suppressive function, inhibiting the progression and proliferation of A549 lung cancer cells. Therefore, it can be concluded that targeting DLGAP1-AS2 using specific siRNA in combination with carboplatin chemotherapy holds promise as a valuable therapeutic approach for lung cancer.

Dual-Accelerated Signal Amplification in Biosensing via Spatial Confining Catalytic Hairpin Assembly-Activated Spherical CRISPR/Cas12a System for Trans-Cleavage of Hairpin DNA Reporters

MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression and are implicated in various diseases, including cancer. Due to their critical role in diagnostics, there is a growing need for sensitive, specific, and rapid detection methods for miRNAs. In this study, we present a dual-accelerated signal amplification platform for miRNA biosensing, which integrates spatial confining catalytic hairpin assembly (SC-CHA) with spherical CRISPR/Cas12a (S-CRISPR/Cas12a) system for (SC-CHA@S-CRISPR/Cas12a) trans-cleavage of hairpin DNA reporters. The method employs a biotinylated palindrome-rich assembly sequence (PAS) to form DNA nanoballs, which serve as a scaffold for the operation of SC-CHA upon miRNA binding. The SC-CHA products bind with crRNA and Cas 12a protein, activating S-CRISPR/Cas12a system to cleave the hairpin DNA reporter and generate a detectable fluorescence signal. The uniqueness of this system lies in the combined use of DNA nanoballs and hairpin DNA reporters, both of which significantly accelerate reaction kinetics, resulting in rapid signal generation. Additionally, the spherical DNA nanostructure, integrated with the S-CRISPR/Cas12a system, greatly enhances biostability and accelerating reaction kinetics. These features enable the platform to exhibit high sensitivity, with a limit of detection (LOD) as low as 13.75 fM, and excellent specificity, successfully distinguishing miRNA-21 from other miRNAs. The assay is also biostable, demonstrating reliable performance in complex biological samples such as human serum. This dual-acceleration approach offers a promising solution for sensitive, rapid, and specific miRNA biosensing, with potential applications in early cancer diagnosis and clinical monitoring.

Photochemical Stabilization of Self-Assembled Spherical Nucleic Acids

Oligonucleotide therapeutics, including antisense oligonucleotides and small interfering RNA, offer promising avenues for modulating the expression of disease-associated proteins. However, challenges such as nuclease degradation, poor cellular uptake, and unspecific targeting hinder their application. To overcome these obstacles, spherical nucleic acids have emerged as versatile tools for nucleic acid delivery in biomedical applications. Our laboratory has introduced sequence-defined DNA amphiphiles which self-assemble in aqueous solutions. Despite their advantages, self-assembled SNAs can be inherently fragile due to their reliance on non-covalent interactions and fall apart in biologically relevant conditions, specifically by interaction with serum proteins. Herein, this challenge is addressed by introducing two methods of covalent crosslinking of SNAs via UV irradiation. Thymine photodimerization or disulfide crosslinking at the micellar interface enhance SNA stability against human serum albumin binding. This enhanced stability, particularly for disulfide crosslinked SNAs, leads to increased cellular uptake. Furthermore, this crosslinking results in sustained activity and accessibility for release of the therapeutic nucleic acid, along with improvement in unaided gene silencing. The findings demonstrate the efficient stabilization of SNAs through UV crosslinking, influencing their cellular uptake, therapeutic release, and ultimately, gene silencing activity. These studies offer promising avenues for further optimization and exploration of pre-clinical, in vivo studies.

Aptamer-conjugated gold nanoparticles enable oligonucleotide delivery into muscle stem cells to promote regeneration of dystrophic muscles

Inefficient targeting of muscle stem cells (MuSCs), also called satellite cells, represents a major bottleneck of current therapeutic strategies for muscular dystrophies, as it precludes the possibility of promoting compensatory regeneration. Here we describe a muscle-targeting delivery platform, based on gold nanoparticles, that enables the release of therapeutic oligonucleotides into MuSCs. We demonstrate that AuNPs conjugation to an aptamer against α7/β1 integrin dimers directs either local or systemic delivery of microRNA-206 to MuSCs, thereby promoting muscle regeneration and improving muscle functionality, in a mouse model of Duchenne Muscular Dystrophy. We show here that this platform is biocompatible, non-toxic, and non-immunogenic, and it can be easily adapted for the release of a wide range of therapeutic oligonucleotides into diseased muscles.

DNA Nanostructures: Advancing Cancer Immunotherapy

Cancer immunotherapy is a groundbreaking medical revolution and a paradigm shift from traditional cancer treatments, harnessing the power of the immune system to target and destroy cancer cells. In recent years, DNA nanostructures have emerged as prominent players in cancer immunotherapy, exhibiting immense potential due to their controllable structure, surface addressability, and biocompatibility. This review provides an overview of the various applications of DNA nanostructures, including scaffolded DNA, DNA hydrogels, tetrahedral DNA nanostructures, DNA origami, spherical nucleic acids, and other DNA-based nanostructures in cancer immunotherapy. These applications explore their roles in vaccine development, immune checkpoint blockade therapies, adoptive cellular therapies, and immune-combination therapies. Through rational design and optimization, DNA nanostructures significantly bolster the immunogenicity of the tumor microenvironment by facilitating antigen presentation, T-cell activation, tumor infiltration, and precise immune-mediated tumor killing. The integration of DNA nanostructures with cancer therapies ushers in a new era of cancer immunotherapy, offering renewed hope and strength in the battle against this formidable foe of human health.

DENV Peptides Delivered as Spherical Nucleic Acid Constructs Enhance Antigen Presentation and Immunogenicity in vitro and in vivo

Background

The global prevalence of Dengue virus (DENV) infection poses a significant health risk, urging the need for effective vaccinations. Peptide vaccines, known for their capacity to induce comprehensive immunity against multiple virus serotypes, offer promise due to their stability, safety, and design flexibility. Spherical nucleic acid (SNA), particularly those with gold nanoparticle cores, present an attractive avenue for enhancing peptide vaccine efficacy due to their modularity and immunomodulatory properties.

Methods

The spherical nucleic acid-TBB (SNA-TBB), a novel nanovaccine construct, was fabricated through the co-functionalization process of SNA with epitope peptide, targeting all four serotypes of the DENV. This innovative approach aims to enhance immunogenicity and provide broad-spectrum protection against DENV infections. The physicochemical properties of SNA-TBB were characterized using dynamic light scattering, zeta potential measurement, and transmission electron microscopy. In vitro assessments included endocytosis studies, cytotoxicity evaluation, bone marrow-dendritic cells (BMDCs) maturation and activation analysis, cytokine detection, RNA sequencing, and transcript level analysis in BMDCs. In vivo immunization studies in mice involved evaluating IgG antibody titers, serum protection against DENV infection and safety assessment of nanovaccines.

Results

SNA-TBB demonstrated successful synthesis, enhanced endocytosis, and favorable physicochemical properties. In vitro assessments revealed no cytotoxicity and promoted BMDCs maturation. Cytokine analyses exhibited heightened IL-12p70, TNF-α, and IL-1β levels. Transcriptomic analysis highlighted genes linked to BMDCs maturation and immune responses. In vivo studies immunization with SNA-TBB resulted in elevated antigen-specific IgG antibody levels and conferred protection against DENV infection in neonatal mice. Evaluation of in vivo safety showed no signs of adverse effects in vital organs.

Conclusion

The study demonstrates the successful development of SNA-TBB as a promising nanovaccine platform against DENV infection and highlights the potential of SNA-based peptide vaccines as a strategy for developing safe and effective antiviral immunotherapy.

DNA-Engineered Degradable Invisibility Cloaking for Tumor-Targeting Nanoparticles

Nanoparticle (NP) delivery systems have been actively exploited for cancer therapy and vaccine development. Nevertheless, the major obstacle to targeted delivery lies in the substantial liver sequestration of NPs. Here we report a DNA-engineered approach to circumvent liver phagocytosis for enhanced tumor-targeted delivery of nanoagents in vivo. We find that a monolayer of DNA molecules on the NP can preferentially adsorb a dysopsonin protein in the serum to induce functionally invisibility to livers; whereas the tumor-specific uptake is triggered by the subsequent degradation of the DNA shell in vivo. The degradation rate of DNA shells is readily tunable by the length of coated DNA molecules. This DNA-engineered invisibility cloaking (DEIC) is potentially generic as manifested in both Ag2S quantum dot- and nanoliposome-based tumor-targeted delivery in mice. Near-infrared-II imaging reveals a high tumor-to-liver ratio of up to ∼5.1, approximately 18-fold higher than those with conventional nanomaterials. This approach may provide a universal strategy for high-efficiency targeted delivery of theranostic agents in vivo.

Recent advances in gene delivery nanoplatforms based on spherical nucleic acids

Gene therapy is a therapeutic option for mitigating diseases that do not respond well to pharmacological therapy. This type of therapy allows for correcting altered and defective genes by transferring nucleic acids to target cells. Notably, achieving a desirable outcome is possible by successfully delivering genetic materials into the cell. In-vivo gene transfer strategies use two major classes of vectors, namely viral and nonviral. Both of these systems have distinct pros and cons, and the choice of a delivery system depends on therapeutic objectives and other considerations. Safe and efficient gene transfer is the main feature of any delivery system. Spherical nucleic acids (SNAs) are nanotechnology-based gene delivery systems (i.e., non-viral vectors). They are three-dimensional structures consisting of a hollow or solid spherical core nanoparticle that is functionalized with a dense and highly organized layer of oligonucleotides. The unique structural features of SNAs confer them a high potency in internalization into various types of tissue and cells, a high stability against nucleases, and efficay in penetrating through various biological barriers (such as the skin, blood-brain barrier, and blood-tumor barrier). SNAs also show negligible toxicity and trigger minimal immune response reactions. During the last two decades, all these favorable physicochemical and biological attributes have made them attractive vehicles for drug and nucleic acid delivery. This article discusses the unique structural properties, types of SNAs, and also optimization mechanisms of SNAs. We also focus on recent advances in the synthesis of gene delivery nanoplatforms based on the SNAs.

Smart Stimuli-Responsive Spherical Nucleic Acids: Cutting-Edge Platforms for Biosensing, Bioimaging, and Therapeutics

Spherical nucleic acids (SNAs) with exceptional colloidal stability, multiple modularity, and programmability are excellent candidates to address common molecular delivery-related issues. Based on this, the higher targeting accuracy and enhanced controllability of stimuli-responsive SNAs render them precise nanoplatforms with inestimable prospects for diverse biomedical applications. Therefore, tailored diagnosis and treatment with stimuli-responsive SNAs may be a robust strategy to break through the bottlenecks associated with traditional nanocarriers. Various stimuli-responsive SNAs are engineered through the incorporation of multifunctional modifications to meet biomedical demands with the development of nucleic acid functionalization. This review provides a comprehensive overview of prominent research in this area and recent advancements in the utilization of stimuli-responsive SNAs in biosensing, bioimaging, and therapeutics. For each aspect, SNA nanoplatforms that exhibit responsive behavior to both internal stimuli (including sequence, enzyme, redox reactions, and pH) and external stimuli (such as light and temperature) are highlighted. This review is expected to offer inspiration and guidance strategies for the rational design and development of stimuli-responsive SNAs in the field of biomedicine.

Life at the interface: Engineering bio-nanomaterials through interfacial molecular self-assembly

Interfacial self-assembly describes the directed organization of molecules and colloids at phase boundaries. Believed to be fundamental to the inception of primordial life, interfacial assembly is exploited by a myriad of eukaryotic and prokaryotic organisms to execute physiologic activities and maintain homeostasis. Inspired by these natural systems, chemists, engineers, and materials scientists have sought to harness the thermodynamic equilibria at phase boundaries to create multi-dimensional, highly ordered, and functional nanomaterials. Recent advances in our understanding of the biophysical principles guiding molecular assembly at gas-solid, gas-liquid, solid-liquid, and liquid-liquid interphases have enhanced the rational design of functional bio-nanomaterials, particularly in the fields of biosensing, bioimaging and biotherapy. Continued development of non-canonical building blocks, paired with deeper mechanistic insights into interphase self-assembly, holds promise to yield next generation interfacial bio-nanomaterials with unique, and perhaps yet unrealized, properties. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Recent Advances in Engineering Carriers for siRNA Delivery

RNA interference (RNAi) technology has been a promising treatment strategy for combating intractable diseases. However, the applications of RNAi in clinical are hampered by extracellular and intracellular barriers. To overcome these barriers, various siRNA delivery systems have been developed in the past two decades. The first approved RNAi therapeutic, Patisiran (ONPATTRO) using lipids as the carrier, for the treatment of amyloidosis is one of the most important milestones. This has greatly encouraged researchers to work on creating new functional siRNA carriers. In this review, the recent advances in siRNA carriers consisting of lipids, polymers, and polymer-modified inorganic particles for cancer therapy are summarized. Representative examples are presented to show the structural design of the carriers in order to overcome the delivery hurdles associated with RNAi therapies. Finally, the existing challenges and future perspective for developing RNAi as a clinical modality will be discussed and proposed. It is believed that the addressed contributions in this review will promote the development of siRNA delivery systems for future clinical applications.

Control of the Assembly and Disassembly of Spherical Nucleic Acids Is Critical for Enhanced Gene Silencing

Spherical nucleic acids─nanospheres with nucleic acids on their corona─have emerged as a promising class of nanocarriers, aiming to address the shortcomings of traditional nucleic therapeutics, namely, their poor stability, biodistribution, and cellular entry. By conjugating hydrophobic monomers to a growing nucleic acid strand in a sequence-defined manner, our group has developed self-assembled spherical nucleic acids (SaSNAs), for unaided, enhanced gene silencing. By virtue of their self-assembled nature, SaSNAs can disassemble under certain conditions in contrast to covalent or gold nanoparticle SNAs. Gene silencing involves multiple steps including cellular uptake, endosomal escape, and therapeutic cargo release. Whether assembly vs disassembly is advantageous to any of these steps has not been previously studied. In this work, we modify the DNA and hydrophobic portions of SaSNAs and examine their effects on stability, cellular uptake, and gene silencing. When the linkages between the hydrophobic units are changed from phosphate to phosphorothioate, we find that the SaSNAs disassemble better in endosomal conditions and exhibit more efficacious silencing, despite having cellular uptake similar to that of their phosphate counterparts. Thus, disassembly in the endolysosomal compartments is advantageous, facilitating the release of the nucleic acid cargo and the interactions between the hydrophobic units and endosomal lipids. We also find that SaSNAs partially disassemble in serum to bind albumin; the disassembled, albumin-bound strands are less efficient at cellular uptake and gene silencing than their assembled counterparts, which can engage scavenger receptors for internalization. When the DNA portion is cross-linked by G-quadruplex formation, disassembly decreases and cellular uptake significantly increases. However, this does not translate to greater gene silencing, again illustrating the need for disassembly of the SaSNAs when they are in the endosome. This work showcases the advantages of the dual nature of SaSNAs for gene silencing, requiring extracellular assembly and disassembly inside the cell compartments.

Construction and bioanalytical applications of poly-adenine-mediated gold nanoparticle-based spherical nucleic acids

Owing to the versatile photophysical and chemical properties, spherical nucleic acids (SNAs) have been widely used in biosensing. However, traditional SNAs are formed by self-assembly of thiolated DNA on the surface of a gold nanoparticle (AuNP), where it is challenging to precisely control the orientation and surface density of DNA. As a new SNA, a polyadenine (polyA)-mediated SNA using the high binding affinity of consecutive adenines to AuNPs shows controllable surface density and configuration of DNA, which can be used to improve the performance of a biosensor. Herein, we first introduce the properties of polyA-mediated SNAs and fundamental principles regarding the polyA-AuNP interaction. Then, we provide an overview of current representative synthesis methods of polyA-mediated SNAs and their advantages and disadvantages. After that, we summarize the application of polyA-mediated SNAs in biosensing based on fluorescence and colorimetric methods, followed by discussion and an outlook of future challenges in this field.

Recent Advances in DNA Nanomaterials

Applications of DNA-containing nanomaterials (DNA-NMs) in science and technology are currently attracting increasing attention in the fields of medicine, environment, engineering, etc. Such objects have become important for various branches of science and industries due to their outstanding characteristics such as small size, high controllability, clustering actions, and strong permeability. For these reasons, DNA-NMs deserve a review with respect to their recent advancements. On the other hand, precise cluster control, targeted drug distribution in vivo, and cellular micro-nano operation remain as problems. This review summarizes the recent progress in DNA-NMs and their crossover and integration into multiple disciplines (including in vivo/in vitro, microcircles excisions, and plasmid oligomers). We hope that this review will motivate relevant practitioners to generate new research perspectives and boost the advancement of nanomanipulation.

Three-Dimensional Nucleic Acid Nanostructures Based on Self-Assembled Polymer-Oligonucleotide Conjugates of Comblike and Coil-Comb Chain Architectures

Spherical nucleic acids have emerged as a class of nanostructures, exhibiting a wide variety of properties, distinctly different from those of linear nucleic acids, and a plethora of applications in therapeutics and diagnostics. Herein, we report on preparation of 3D nucleic acid nanostructures, prepared by self-assembly of polymer-oligonucleotide conjugates. The latter are obtained by grafting multiple alkyne-functionalized oligonucleotide strands onto azide-modified homo-, block, and random (co)polymers of chloromethylstyrene via initiator-free click coupling chemistry to form conjugates of comblike and coil-comb chain architectures. The resulting conjugates are amphiphilic and form stable nanosized supramolecular structures in aqueous solution. The nanoconstructs are thoroughly investigated and a number of physical characteristics, in particular, molar mass, size, aggregation number, zeta potential, material density, number of oligonucleotide strands per particle, grafting density, and their relation to hallmark properties of spherical nucleic acids - biocompatibility, resistance against DNase I, cellular uptake without the need for transfection agents - are determined.

Research advances in nanomedicine applied to the systemic treatment of colorectal cancer

The systematic treatment of colorectal cancer (CRC) still has room for improvement. The efficacy of chemotherapy, that of anti-vascular therapy, and that of immunotherapy have been unsatisfactory. In recent years, nanomaterials have been used as carriers to improve the bioavailability of anticancer drugs. For the treatment of colorectal cancer, nanodrugs increase the possibility of more precise targeted delivery. However, the actual benefits may cover more aspects. Nanocarriers can produce synergistic effects with anticancer drugs, including the scavenging of reactive oxygen species and co-delivery of a variety of drugs. Currently, immunotherapy has very limited clinical applications in CRC. Modified nanocarriers can activate the immune microenvironment, which can be used for staging antigen recognition or the immune response. Cancer vaccines based on nanomaterials and modified immune checkpoint inhibitors have shown therapeutic potential in animal models. Considering the direct or indirect relationship between the intestinal microflora and CRC, a variety of nanodrugs that regulate microbial function have been explored as an anticancer strategy, and the special structure of microorganisms can also be used as a basis for improving the delivery of traditional nanoparticles (NPs). This review summarizes recent research performed on nanocarriers in in vivo and in vitro models and the synergistic anticancer effects of nanocarriers, focusing on the interaction between NPs and the body, resulting in enhanced efficacy and immune activation. Furthermore, this review describes the current trend of NPs used in the treatment of CRC.

Anomalous kinetic study of atenolol release from ATN@DNA a core-shell like structure

The need for more efficient drug delivery strategies with ultraprecision and control over the release of drugs has led to the growth of more sophisticated drug-releasing systems as a promising alternative to conventional clinical therapies. This new seed of strategies has explored an encouraging property to overcome the inherent problems of traditional therapies. One of the major challenges for any drug delivery system is the introduction of a complete view of the delivery system. In this article, we intend to elucidate the theoretical proof of concept of the electrosynthesis ATN@DNA core-shell like structure as a model system. Therefore, we present a fractal kinetic model (non-exponential model) taking into consideration the concept of time-dependent diffusion coefficient, which was developed using a numerical method with the help of COMSOL Multiphysics. In addition to that, we present here a general fractional kinetic model in sense of the tempered fractional operator, which leads to better characterized memory properties of the release process. Also, the fractional model is compared with the fractal kinetic model and both offer a good description of drug release processes that present anomalous kinetics. The solutions of the fractal and fractional kinetic models are also fitted successfully with our real-release results.

Suppression of Lung Cancer Malignancy by Micellized siRNA through Cell Cycle Arrest

UBA6-specific E2 conjugation enzyme 1 (USE1) is frequently overexpressed in lung cancer patients. Moreover, the critical role of USE1 in the progression of human lung cancer is also indicated. As the next step, the authors aim to develop USE1-targeted therapeutic agents based on RNA interference (RNAi). In this study, a lipid-modified DNA carrier, namely U4T, which consists of four consecutive dodec-1-ynyluracil (U) nucleobases to increase the cell permeability of siRNA targeting of USE1 is introduced. The U4Ts aggregate to form micelles, and the USE1-silencing siRNA-incorporated soft spherical nucleic acid aggregate (siSNA) can be created simply through base-pairing with siRNA. Treatment with siSNA is effective in suppressing tumor growth in vivo as well as cell proliferation, migration, and invasion of lung cancer cells. Furthermore, siSNA inhibited tumor cell growth by inducing cell cycle arrest in the G1 phase and apoptosis. Thus, the anti-tumor efficacy of siSNA in lung cancer cell lines and that siSNA possesses effective cell-penetrating ability without using cationic transfection moieties are confirmed. Collectively, these results suggest that siSNA can be applied to the clinical application of RNAi-based therapeutics for lung cancer treatment.

DNA Nanomaterial-Based Optical Probes for Exosomal miRNA Detection

Micro ribonucleic acids (miRNAs) in exosomes have been proven as reliable biomarkers to detect disease progression. In recent years, deoxyribonucleic acid (DNA)-based nanomaterials show great potential in the field of diagnosis due to the programmable sequence, various molecule recognition and predictable assembly/disassembly of DNA. In this review, we focus on the molecular design and detection mechanism of DNA nanomaterials, and the developed DNA nanomaterial-based optical probes for exosomal miRNA detection are summarized and discussed. The rationally-designed DNA sequences endows these probes with low background signal and high sensitivity in exosomal miRNA detection, and the detection mechanisms based on different DNA nanomaterials are detailly introduced. At the end, the challenges and future opportunities of DNA nanomaterial-based optical probes in exosomal miRNA detection are discussed. We envision that DNA nanomaterial-based optical probes will be promising in precise biomedicine.

RGD_PLGA Nanoparticles with Docetaxel: A Route for Improving Drug Efficiency and Reducing Toxicity in Breast Cancer Treatment

Breast cancer is the leading cause of cancer-related death in women. Although many therapeutic approaches are available, systemic chemotherapy remains the primary choice, especially for triple-negative and advanced breast cancers. Unfortunately, systemic chemotherapy causes serious side effects and requires high doses to achieve an effective concentration in the tumor. Thus, the use of nanosystems for drug delivery may overcome these limitations. Herein, we formulated Poly (lactic-co-glycolic acid) nanoparticles (PLGA-NPs) containing Docetaxel, a fluorescent probe, and a magnetic resonance imaging (MRI) probe. The cyclic RGD tripeptide was linked to the PLGA surface to actively target α_vβ₃ integrins, which are overexpressed in breast cancer. PLGA-NPs were characterized using dynamic light scattering, fast field-cycling ¹H-relaxometry, and ¹H-nuclear magnetic resonance. Their therapeutic effects were assessed both in vitro in triple-negative and HER2+ breast cancer cells, and in vivo in murine models. In vivo MRI and inductively coupled plasma mass spectrometry of excised tumors revealed a stronger accumulation of PLGA-NPs in the RGD_PLGA group. Targeted PLGAs have improved therapeutic efficacy and strongly reduced cardiac side effects compared to free Docetaxel. In conclusion, RGD-PLGA is a promising system for breast cancer treatment, with positive outcome in terms of therapeutic efficiency and reduction in side effects.

Original Synthesis of a Nucleolipid for Preparation of Vesicular Spherical Nucleic Acids

Spherical nucleic acids (SNAs)-nanostructures, consisting of a nanoparticle core densely functionalized with a shell of short oligonucleotide strands-are a rapidly emerging class of nanoparticle-based therapeutics with unique properties and specific applications as drug and nucleic acid delivery and gene regulation materials. In this contribution, we report on the preparation of hollow SNA nanoconstructs by co-assembly of an originally synthesized nucleolipid-a hybrid biomacromolecule, composed of a lipidic residue, covalently linked to a DNA oligonucleotide strand-with other lipids. The nucleolipid was synthesized via a click chemistry approach employing initiator-free, UV light-induced thiol-ene coupling of appropriately functionalized intermediates, performed in mild conditions using a custom-made UV light-emitting device. The SNA nanoconstructs were of a vesicular structure consisting of a self-closed bilayer membrane in which the nucleolipid was intercalated via its lipid-mimetic residue. They were in the lower nanometer size range, moderately negatively charged, and were found to carry thousands of oligonucleotide strands per particle, corresponding to a grafting density comparable to that of other SNA structures. The surface density of the strands on the bilayer implied that they adopted an unextended conformation. We demonstrated that preformed vesicular structures could be successfully loaded with either hydrophilic or hydrophobic dyes.

Nanoparticles Loaded with Platinum Drugs for Colorectal Cancer Therapy

Colorectal cancer is a common cancer in both men and women. Numerous studies on the therapeutic effectiveness of nanoparticles against colorectal cancer have been reported. Platinum treatments as well as other medications comprising of nanoparticles have been utilized. Drug resistance restricts the use of platinum medicines, despite their considerable efficacy against a variety of cancers. This review reports clinically licensed platinum medicines (cisplatin, carboplatin, and oxaliplatin) combined with various nanoparticles that have been evaluated for their therapeutic efficacy in the treatment of colorectal cancer, including their mechanism of action, resistance, and limitations.

Conductive and Semiconductive Nanocomposite-Based Hydrogels for Cardiac Tissue Engineering

Cardiovascular disease is the leading cause of death worldwide and the most common cause is myocardial infarction. Therefore, appropriate approaches should be used to repair damaged heart tissue. Recently, cardiac tissue engineering approaches have been extensively studied. Since the creation of the nature of cardiovascular tissue engineering, many advances have been made in cellular and scaffolding technologies. Due to the hydrated and porous structures of the hydrogel, they are used as a support matrix to deliver cells to the infarct tissue. In heart tissue regeneration, bioactive and biodegradable hydrogels are required by simulating native tissue microenvironments to support myocardial wall stress in addition to preserving cells. Recently, the use of nanostructured hydrogels has increased the use of nanocomposite hydrogels and has revolutionized the field of cardiac tissue engineering. Therefore, to overcome the limitation of the use of hydrogels due to their mechanical fragility, various nanoparticles of polymers, metal, and carbon are used in tissue engineering and create a new opportunity to provide hydrogels with excellent properties. Here, the types of synthetic and natural polymer hydrogels, nanocarbon-based hydrogels, and other nanoparticle-based materials used for cardiac tissue engineering with emphasis on conductive nanostructured hydrogels are briefly introduced.

Recent developments in the use of gold and silver nanoparticles in biomedicine

Gold and silver nanoparticles (NPs) are widely used in the biomedical research both in the therapeutic and the sensing/diagnostics fronts. Both metals share some common optical properties with surface plasmon resonance being the most widely exploited property in therapeutics and diagnostics. Au NPs exhibit excellent light‐to‐heat conversion efficiencies and hence have found applications primarily in precision oncology, while Ag NPs have excellent antibacterial properties which can be harnessed in biomaterials' design. Both metals constitute excellent biosensing platforms owing to their plasmonic properties and are now routinely used in various optical platforms. The utilization of Au and Ag NPs in the COVID‐19 pandemic was rapidly expanded mostly in biosensing and point‐of‐care platforms and to some extent in therapeutics. In this review article, the main physicochemical properties of Au and Ag NPs are discussed with selective examples from the recent literature.

This article is categorized under:

Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease

Diagnostic Tools > In Vitro Nanoparticle‐Based Sensing

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology

RNA-based therapeutics: an overview and prospectus

The growing understanding of RNA functions and their crucial roles in diseases promotes the application of various RNAs to selectively function on hitherto "undruggable" proteins, transcripts and genes, thus potentially broadening the therapeutic targets. Several RNA-based medications have been approved for clinical use, while others are still under investigation or preclinical trials. Various techniques have been explored to promote RNA intracellular trafficking and metabolic stability, despite significant challenges in developing RNA-based therapeutics. In this review, the mechanisms of action, challenges, solutions, and clinical application of RNA-based therapeutics have been comprehensively summarized.

Recent advances in nanoparticle-based photothermal therapy for breast cancer

Breast cancer is one of the most common cancers among women that is associated with high mortality. Conventional treatments including surgery, radiotherapy, and chemotherapy, which are not effective enough and have disadvantages such as toxicity and damage to healthy cells. Photothermal therapy (PTT) of cancer cells has been took great attention by researchers in recent years due to the use of light radiation and heat generation at the tumor site, which thermal ablation is considered a minimally invasive method for the treatment of breast cancer. Nanotechnology has opened up a new perspective in the treatment of breast cancer using PTT method. Through NIR light absorption, researchers applied various nanostructures because of their specific nature of penetrating and targeting tumor tissue, increasing the effectiveness of PTT, and combining it with other treatments. If PTT is used with common cancer treatments, it can dramatically increase the effectiveness of treatment and reduce the side effects of other methods. PTT performance can also be improved by hybridizing at least two different nanomaterials. Nanoparticles that intensely absorb light and increase the efficiency of converting light into heat can specifically kill tumors through hyperthermia of cancer cells. One of the main reasons that have increased the efficiency of nanoparticles in PTT is their permeability and durability effect and they can accumulate in tumor tissue. Targeted PTT can be provided by incorporating specific ligands to target receptors expressed on the surface of cancer cells on nanoparticles. These nanoparticles can specifically target cancer cells by maintaining the surface area and increasing penetration. In this study, we briefly introduce the performance of light therapy, application of metal nanoparticles, polymer nanoparticles, carbon nanoparticles, and hybrid nanoparticles for use in PTT of breast cancer.

Preparation of a miR-155-activating nucleic acid nanoflower to study the molecular mechanism of miR-155 in inflammation

At present, the molecular mechanisms underlying inflammation remain unclear. In recent years, research on inflammation has focused on stimulating cell inflammation by using exogenous pro-inflammatory substances such as lipopolysaccharide (LPS) or inflammatory factors. To investigate the molecular mechanism of inflammation from a new perspective, we designed a nucleic acid nanoflowers (NFs) complex to directly activate inflammatory genes to study the inflammatory response without the need for external microbial factors to trigger an inflammatory response. An RNAa-type target gene-activated NFs was designed. Human umbilical vein endothelial cells (HUVECs) were transfected with NFs carrying small activating RNA (saRNAs) to directly co-activate microRNA (miR)-155 and SHIP1 genes. After RNA activation (RNAa)-type NFs were transferred into HUVECs, the expression of miR-155 and pro-inflammatory and cancer-related factors increased, anti-inflammatory factors were reduced, cell proliferation increased, and cell migration was promoted. IL-1β protein levels were decreased and SHIP1 expression was downregulated. When miR-155 and its target SHIP1 were both activated, the expression of both was unaltered, maintaining cell homeostasis. This points towards miR-155 overexpression can trigger inflammation, and that miR-155 and its target genes act as a molecular switch role in the development of inflammation.

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.

Light-Harvesting Fluorescent Spherical Nucleic Acids Self-Assembled from a DNA-Grafted Conjugated Polymer for Amplified Detection of Nucleic Acids

The ultralow concentration of nucleic acids in complex biological samples requires fluorescence probes with high specificity and sensitivity. Herein, a new kind of spherical nucleic acids (SNAs) is developed by using fluorescent π-conjugated polymers (FCPs) as a light-harvesting antenna to enhance the signal transduction of nucleic acid detection. Specifically, amphiphilic DNA-grafted FCPs are synthesized and self-assemble into FCP-SNA structures. Tuning the hydrophobicity of the graft copolymer can adjust the size and light-harvesting capability of the FCP-SNAs. We observe that more efficient signal amplification occurs in larger FCP-SNAs, as more chromophores are involved, and the energy transfer can go beyond the Förster radius. Accordingly, the optimized FCP-SNA shows an antenna effect of up to 37-fold signal amplification and the limit of detection down to 1.7 pM in microRNA detection. Consequently, the FCP-SNA is applied to amplified in situ nucleic acid detecting and imaging at the single-cell level.

Gene Regulation Using Nanodiscs Modified with HIF-1-α Antisense Oligonucleotides

Delivery of nucleic acids can be hindered by multiple factors including nuclease susceptibility, endosome trapping, and clearance. Multiple nanotechnology scaffolds have offered promising solutions, and among these, lipid-based systems are advantageous because of their high biocompatibility and low toxicity. However, many lipid nanoparticle systems still have issues regarding stability, rapid clearance, and cargo leakage. Herein, we demonstrate the use of a synthetic nanodisc (ND) scaffold functionalized with an anti-HIF-1-α antisense oligonucleotide (ASO) to reduce HIF-1-α mRNA transcript levels. We prepared ND conjugates by using a mixture of phosphoglycerolipids with phosphocholine and phosphothioethanol headgroups that self-assemble into a ∼13 × 5 nm discoidal structure upon addition of a 22-amino-acid ApoA1 mimetic peptide. Optimized reaction conditions yield 15 copies of the anti-HIF-1-α ASO DNA covalently conjugated to the thiolated phospholipids using maleimide-thiol chemistry. We show that DNA-ND conjugates are active, nuclease resistant, and rapidly internalized into cells to regulate HIF-1-α mRNA levels without the use of transfection agents. DNA-ND uptake is partially mediated through Scavenger Receptor B1 and the ND conjugates show enhanced knockdown of HIF-1-α compared to that of the soluble ASOs in multiple cell lines. Our results demonstrate that covalently functionalized NDs may offer an improved platform for ASO therapeutics.

Transdermal delivery of poly-hyaluronic acid-based spherical nucleic acids for chemogene therapy

Spherical nucleic acid (SNA), as a good gene delivery system, has a good application prospect for transdermal administration in skin disorder treatment. However, most of the traditional SNA core materials are non-degradable materials, so it is worthy of further research. Herein, we report a spherical nucleic acid based on poly-hyaluronic acid (PHA) for the co-delivery of a typical chemotherapeutic drug, doxorubicin (DOX), and an antisense oligonucleotide (ASO) against the tissue inhibitor of metalloproteinases 1 (TIMP-1) for the treatment of hypertrophic scars (HS) which are caused by abnormal fibroblast proliferation. Our study showed that PHA-based SNAs simultaneously bearing TIMP-1 ASO and DOX (termed PHAAD) could significantly promote skin penetration, improve the cellular uptake, and effectively down-regulate the TIMP-1 expression and enhance the cytotoxicity of DOX. Moreover, PHAAD nanoparticles facilitated the apoptosis of hypertrophic scar cells, and reduced the burden and progression of hypertrophic scars in a xenografted mouse model without adverse side effects. Thus, our PHA-based SNA represents a new transdermal delivery vehicle for efficient combinatorial chemo and gene therapy, which is expected to treat various skin disorders.

Simultaneous nanocarrier-mediated delivery of siRNAs and chemotherapeutic agents in cancer therapy and diagnosis: Recent advances

Recently, investigations have revealed that RNA interference (RNAi) has a remarkable potential to decrease cancer burden by downregulating genes. Among various RNAi molecules, small interfering RNA (siRNA) has been more attractive for this goal and is able to silence a target pathological path and promote the degradation of a certain mRNA, resulting in either gain or loss of function of proteins. Moreover, therapeutic siRNAs have exhibited low side effects compared to other therapeutic molecular candidates. Nevertheless, siRNA delivery has its own limitations including quick degradation in circulation, ineffective internalization and low passive uptake by cells, possible toxicity against off-target sites, and inducing unfavorable immune responses. Therefore, delivery tools must be able to specifically direct siRNAs to their target locations without inflicting detrimental effects on other sites. To conquer the mentioned problems, nanocarrier-mediated delivery of siRNAs, using inorganic nanoparticles (NPs), polymers, and lipids, has been developed as a biocompatible delivery approach. In this review, we have discussed recent advances in the siRNA delivery methods that employ nanoparticles, lipids, and polymers, as well as the inorganic-based co-delivery systems used to deliver siRNAs and anticancer agents to target cells.

Conjugation of Nucleic Acids and Drugs to Gold Nanoparticles

Gold nanoparticles (AuNPs) can be used as carriers for biomolecules or drugs in cell culture and animal models. Particularly, AuNPs ease their internalization into the cell and prevent their degradation. In addition, engineered AuNPs can be employed as sensors of a variety of biomarkers, where the electronic and optical properties of the AuNPs are exploited for a convenient, easy, and fast read out. However, in all these applications, a key step requires the conjugation of the different molecules to the nanoparticles. The most common approach exploits the great affinity of sulfur for gold. Herein, we summarize the methods used by our group for the conjugation of different molecules with AuNPs. The procedure is easy and takes around 2 days, where the reagents are slowly added, following an incubation at room temperature to ensure the complete conjugation. Finally, the unbound material is removed by centrifugation.

DNA Nanodevice-Based Drug Delivery Systems

DNA, a natural biological material, has become an ideal choice for biomedical applications, mainly owing to its good biocompatibility, ease of synthesis, modifiability, and especially programmability. In recent years, with the deepening of the understanding of the physical and chemical properties of DNA and the continuous advancement of DNA synthesis and modification technology, the biomedical applications based on DNA materials have been upgraded to version 2.0: through elaborate design and fabrication of smart-responsive DNA nanodevices, they can respond to external or internal physical or chemical stimuli so as to smartly perform certain specific functions. For tumor treatment, this advancement provides a new way to solve the problems of precise targeting, controllable release, and controllable elimination of drugs to a certain extent. Here, we review the progress of related fields over the past decade, and provide prospects for possible future development directions.

The Roles of Non-coding RNA in the Development and Regeneration of Hair Follicles: Current Status and Further Perspectives

Alopecia is a common problem that affects almost every age group and is considered to be an issue for cosmetic or psychiatric reasons. The loss of hair follicles (HFs) and hair caused by alopecia impairs self-esteem, thermoregulation, tactile sensation and protection from ultraviolet light. One strategy to solve this problem is HF regeneration. Many signalling pathways and molecules participate in the morphology and regeneration of HF, such as Wnt/β-catenin, Sonic hedgehog, bone morphogenetic protein and Notch. Non-coding RNAs (ncRNAs), especially microRNAs and long ncRNAs, have significant modulatory roles in HF development and regeneration via regulation of these signalling pathways. This review provides a comprehensive overview of the status and future prospects of ncRNAs in HF regeneration and could prompt novel ncRNA-based therapeutic strategies.

Nanoparticles modified with vasculature-homing peptides for targeted cancer therapy and angiogenesis imaging

The two major challenges in cancer treatment include lack of early detection and ineffective therapies with various side effects. Angiogenesis is the key process in the growth, survival, invasiveness, and metastasis of many of cancerous tumors. Imaging of the angiogenesis could lead to diagnosis of tumors in the early stage and evaluation of the therapeutic responses. Angiogenic blood vessels express specific molecular markers different from normal blood vessels (in level or kind). This fact would make the tumor vasculature a suitable site to target therapeutics and imaging agents within the tumor. Surface modified nanoparticles using peptide ligands with high binding affinity to the vasculature markers, provide efficient delivery of therapeutic and imaging agents, while avoiding undesirable side effects. In this review, we discuss discoveries of various tumor targeting peptides useful for tumor angiogenesis imaging and targeted therapy with emphasis on surface modified nanomedicines using vasculature targeting peptides.

Orally Administrable Therapeutic Nanoparticles for the Treatment of Colorectal Cancer

Colorectal cancer (CRC) is one of the most common and lethal human malignancies worldwide; however, the therapeutic outcomes in the clinic still are unsatisfactory due to the lack of effective and safe therapeutic regimens. Orally administrable and CRC-targetable drug delivery is an attractive approach for CRC therapy as it improves the efficacy by local drug delivery and reduces systemic toxicity. Currently, chemotherapy remains the mainstay modality for CRC therapy; however, most of chemo drugs have low water solubility and are unstable in the gastrointestinal tract (GIT), poor intestinal permeability, and are susceptible to P-glycoprotein (P-gp) efflux, resulting in limited therapeutic outcomes. Orally administrable nanoformulations hold the great potential for improving the bioavailability of poorly permeable and poorly soluble therapeutics, but there are still limitations associated with these regimes. This review focuses on the barriers for oral drug delivery and various oral therapeutic nanoparticles for the management of CRC.

Advanced mechanotherapy: Biotensegrity for governing metastatic tumor cell fate via modulating the extracellular matrix

Mechano-transduction is the procedure of mechanical stimulus translation via cells, among substrate shear flow, topography, and stiffness into a biochemical answer. TAZ and YAP are transcriptional coactivators which are recognized as relay proteins that promote mechano-transduction within the Hippo pathway. With regard to healthy cells in homeostasis, mechano-transduction regularly restricts proliferation, and TAZ and YAP are totally inactive. During cancer development a YAP/TAZ - stimulating positive response loop is formed between the growing tumor and the stiffening ECM. As tumor developments, local stromal and cancerous cells take advantage of mechanotransduction to enhance proliferation, induce their migratory into remote tissues, and promote chemotherapeutic resistance. As a newly progresses paradigm, nanoparticle-conjunctions (such as magnetic nanoparticles, and graphene derivatives nanoparticles) hold significant promises for remote regulation of cells and their relevant events at molecular scale. Despite outstanding developments in employing nanoparticles for drug targeting studies, the role of nanoparticles on cellular behaviors (proliferation, migration, and differentiation) has still required more evaluations in the field of mechanotherapy. In this paper, the in-depth contribution of mechano-transduction is discussed during tumor progression, and how these consequences can be evaluated in vitro.

Covalent Amide-Bonded Nanoflares for High-Fidelity Intracellular Sensing and Targeted Therapy: A Superstable Nanosystem Free of Nonspecific Interferences

A nanoflare, a conjugate of Au nanoparticles (NPs) and fluorescent nucleic acids, is believed to be a powerful nanoplatform for diagnosis and therapy. However, it highly suffers from the nonspecific detachment of nucleic acids from the AuNP surface because of the poor stability of Au-S linkages, thereby leading to the false-positive signal and serious side effects. To address these challenges, we report the use of covalent amide linkage and functional Au@graphene (AuG) NP to fabricate a covalent conjugate system of DNA and AuG NP, label-rcDNA-AuG. Covalent coating of abundant amino groups (-NH₂) onto the graphitic shell of AuG NP efficiently facilitates the coupling with carboxyl-labeled capture DNA sequences through simple, but strong, amide bonds. Importantly, such an amide-bonded nanoflare possesses excellent stability and anti-interference capability against the biological agents (nuclease, DNA, glutathione (GSH), etc.). By accurately monitoring the intracellular miR-21 levels, this covalent nanoflare is able to identify the positive cancer cells even in a mix of cancer and normal cells. Moreover, it allows for efficient photodynamic therapy of the targeted cancer cells with minimized side effects on normal cells. This work provides a facile approach to develop a superstable nanosystem showing promising potential in clinical diagnostics and therapy.

Novel electro self-assembled DNA nanospheres as a drug delivery system for atenolol

We describe new method for preparing DNA nanospheres for a self-assembled atenolol@DNA (core/shell) drug delivery system. In this paper, we propose the electrochemical transformation of an alkaline polyelectrolyte solution of DNA into DNA nanospheres. We successfully electrosynthesized DNA nanospheres that were stable for at least 2 months at 4 °C. UV-visible spectra of the prepared nanospheres revealed a peak ranging from 372 to 392 nm depending on the DNA concentration and from 361 to 398.3 nm depending on the electrospherization time. This result, confirmed with size distribution curves worked out from transmission electron microscopy (TEM) images, showed that increasing electrospherization time (6, 12 and 24 h) induces an increase in the average size of DNA nanospheres (48, 65.5 and 117 nm, respectively). In addition, the average size of DNA nanospheres becomes larger (37.8, 48 and 76.5 nm) with increasing DNA concentration (0.05, 0.1 and 0.2 wt%, respectively). Also, the affinity of DNA chains for the surrounding solvent molecules changed from favorable to bad with concomitant extreme reduction in the zeta potential from -31 mV to -17 mV. Principally, the attractive and hydrophobic interactions tend to compact the DNA chain into a globule, as confirmed by Fourier transform infrared spectroscopy (FTIR) and TEM. To advance possible applications, we successfully electro self-assembled an atenolol@DNA drug delivery system. Our findings showed that electrospherization as a cost-benefit technique could be effectively employed for sustained drug release. This delivery system achieved a high entrapment efficiency of 68.03 ± 2.7% and a moderate drug-loading efficiency of 3.73%. The FTIR spectra verified the absence of any chemical interaction between the drug and the DNA during the electrospherization process. X-ray diffraction analysis indicated noteworthy lessening in atenolol crystallinity. The present findings could aid the effectiveness of electrospherized DNA for use in various other pharmaceutical and biomedical applications.

Immune Cell Membrane-Coated Biomimetic Nanoparticles for Targeted Cancer Therapy

Nanotechnology has provided great opportunities for managing neoplastic conditions at various levels, from preventive and diagnostic to therapeutic fields. However, when it comes to clinical application, nanoparticles (NPs) have some limitations in terms of biological stability, poor targeting, and rapid clearance from the body. Therefore, biomimetic approaches, utilizing immune cell membranes, are proposed to solve these issues. For example, macrophage or neutrophil cell membrane coated NPs are developed with the ability to interact with tumor tissue to suppress cancer progression and metastasis. The functionality of these particles largely depends on the surface proteins of the immune cells and their preserved function during membrane extraction and coating process on the NPs. Proteins on the outer surface of immune cells can render a wide range of activities to the NPs, including prolonged blood circulation, remarkable competency in recognizing antigens for enhanced targeting, better cellular interactions, gradual drug release, and reduced toxicity in vivo. In this review, nano-based systems coated with immune cells-derived membranous layers, their detailed production process, and the applicability of these biomimetic systems in cancer treatment are discussed. In addition, future perspectives and challenges for their clinical translation are also presented.

Size-Dependent Electroporation of Dye-Loaded Polymer Nanoparticles for Efficient and Safe Intracellular Delivery

Efficient and safe delivery of nanoparticles (NPs) into the cytosol of living cells constitutes a major methodological challenge in bio-nanotechnology. Electroporation allows direct transfer of NPs into the cytosol by forming transient pores in the cell membrane, but it is criticized for invasiveness, and the applicable particle sizes are not well defined. Here, in order to establish principles for efficient delivery of NPs into the cytosol with minimal cytotoxicity, the influence of the size of NPs on their electroporation and intracellular behavior is investigated. For this study, fluorescent dye-loaded polymer NPs with core sizes between 10 and 40 nm are prepared. Optimizing the electroporation protocol allows minimizing contributions of endocytosis and to study directly the effect of NP size on electroporation. NPs of <20 nm hydrodynamic size are efficiently delivered into the cytosol, whereas this is not the case for NPs of >30 nm. Moreover, only particles of core size <15 nm diffuse freely throughout the cytosol. While electroporation at excessive electric fields induces cytotoxicity, the use of small NPs <20 nm allows efficient delivery at mild electroporation conditions. These results give clear methodological and design guidelines for the safe delivery of NPs for intracellular applications.

Emerging skin-targeted drug delivery strategies to engineer immunity: A focus on infectious diseases

INTRODUCTION

Infectious pathogens are global disrupters. Progress in biomedical science and technology has expanded the public health arsenal against infectious diseases. Specifically, vaccination has reduced the burden of infectious pathogens. Engineering systemic immunity by harnessing the cutaneous immune network has been particularly attractive since the skin is an easily accessible immune-responsive organ. Recent advances in skin-targeted drug delivery strategies have enabled safe, patient-friendly, and controlled deployment of vaccines to cutaneous microenvironments for inducing long-lived pathogen-specific immunity to mitigate infectious diseases, including COVID-19.

AREAS COVERED

This review briefly discusses the basics of cutaneous immunomodulation and provides a concise overview of emerging skin-targeted drug delivery systems that enable safe, minimally invasive, and effective intracutaneous administration of vaccines for engineering systemic immune responses to combat infectious diseases.

EXPERT OPINION

In-situ engineering of the cutaneous microenvironment using emerging skin-targeted vaccine delivery systems offers remarkable potential to develop diverse immunization strategies against pathogens. Mechanistic studies with standard correlates of vaccine efficacy will be important to compare innovative intracutaneous drug delivery strategies to each other and to existing clinical approaches. Cost-benefit analyses will be necessary for developing effective commercialization strategies. Significant involvement of industry and/or government will be imperative for successfully bringing novel skin-targeted vaccine delivery methods to market for their widespread use.

Cationic (Co)polymers Based on N-Substituted Polyacrylamides as Carriers of Bio-macromolecules: Polyplexes, Micelleplexes, and Spherical Nucleic Acidlike Structures

Novel N-substituted polyacrylamides bearing a cycle with two tertiary amines, poly(4-methyl-piperazin-1-yl)-propenone (PMPP) and its block copolymers with polylactide (PMPP-b-PLA), are synthesized and characterized. The homopolymers are water-soluble, whereas the block copolymers self-assemble in aqueous solution into a small size (R_h around 30 nm), are narrowly distributed, and exhibit core-shell micelles with good colloidal stability. Both the homopolymers and copolymer micelles are positively charged (ζ-potentials in the 13.8-17.6 mV range), which are employed for formation of electrostatic complexes with oppositely charged DNA. Complexes (polyplexes, micelleplexes, and spherical nucleic acidlike structures) in a wide range of N/P (amino to phosphate groups) ratios are prepared with short (115 bp) and long (2000 bp) DNA. The behavior and physicochemical properties of the resulting nanocarriers of DNA are strongly dependent on the polymer/polymer micelles' characteristics and the DNA chain length. All systems exhibit low cytotoxicity and good cellular uptake ability and show promise for gene delivery and regulation.

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.