Blurring the Role of Oligonucleotides: Spherical Nucleic Acids as a Drug Delivery Vehicle

Supramolecular Modulator Assisted Cryo-Engineered Porous Cu-DNA Nano-Vehicles for Versatile Theranostic Agent Delivery

DNA nanotechnology combines structural design with therapeutic functions via programmable DNA motifs, but faces challenges in drug loading capacity. Herein a pore-engineering strategy is reported to develop a highly porous, universal DNA nano-vehicle through coordination self-assembly, cryo-engineering, and supramolecular chemistry, adapting to diverse cargo loading with desired theranostic agents. Thus, the complex synthesis and compatibility challenges typically associated with switching between different drug carriers are avoided. To this end, Cu2+ and nucleic acid therapeutic G3139 self-assemble into a prefabricated solid nanostructure, which subsequently undergoes ultrafast freezing and sublimation to introduce porosity, forming highly porous Cu-G3139 nanoparticles (CG NPs). The porous CG NPs efficiently accommodate diverse therapeutic molecules, from chemotherapeutics to non-chemotherapeutic agents, facilitated by positively-charged cyclodextrin. As a proof-of-concept, the photosensitizer indocyanine green (ICG) is loaded and coated with tannic acid (TA) to form CICG@TA, enabling remarkable photothermal and fluorescence imaging-guided synergistic tumor ablation. This work represents the first demonstration of sublimation-induced pore formation in metal-DNA hybrid nanoparticles without chemical etching, offering a scalable "plug-and-play" platform for personalized cancer therapy without redesign. This versatile pore-engineering strategy, merging supramolecular chemistry with cryo-engineered porosity, opens up new avenues for efficient, customized multidrug delivery for diverse tumor theranostic applications.

Development of small molecule-drug conjugates based on derivatives of natural proteasome inhibitors that exhibit selectivity for PSMA-expressing cancer cells

In this study, we have developedsmall molecule drug conjugates (SMDCs)consisting ofa prostate specific membrane antigen (PSMA) ligandand syringolin derivatives, which are potent proteasome inhibitors, to selectively deliver syringolin derivatives to prostate cancer cells. Two parent compounds were used for syringolin derivatives with different linkage sites. These SMDCs exhibited PSMA-expressing cell-selective cytotoxicity and they could potentially be used for safer treatment of cancer.

Biomarker-triggered, spatiotemporal controlled DNA nanodevice simultaneous assembly and disassembly

Despite many advances in the use of DNA nanodevices as assembly or disassembly modules to build various complex structures, the simultaneous assembly and disassembly of DNA structures in living cells remains a challenge. In this study, we present a modular engineering approach for assembling and disassembling DNA nanodevices in response to endogenous biomarkers. As a result of pairwise prehybridization of original DNA strands, the DNA nanodevice is initially inert. In an effort to bind one of the paired strands and release its complement, nucleolin competes. Assembly of the DNA nanodevice is initiated when the released complement binds to it, and disassembly is initiated when APE1 shears the assembled binding site of the DNA nanodevice. Spatial-temporal logic control is achieved through our approach during the assembly and disassembly of DNA nanodevices. Furthermore, by means of this assembly and disassembly procedure, the sequential detection and imaging of two tumor markers can be achieved, thereby effectively reducing false-positive signal results and accelerating the detection time. This study emphasizes the simultaneous assembly and disassembly of DNA nanodevices controlled by biomarkers in a simple and versatile manner; it has the potential to expand the application scope of DNA nanotechnology and offers an idea for the implementation of precision medicine testing.

From Structure to Application: The Evolutionary Trajectory of Spherical Nucleic Acids

Since the proposal of the concept of spherical nucleic acids (SNAs) in 1996, numerous studies have focused on this topic and have achieved great advances. As a new delivery system for nucleic acids, SNAs have advantages over conventional deoxyribonucleic acid (DNA) nanostructures, including independence from transfection reagents, tolerance to nucleases, and lower immune reactions. The flexible structure of SNAs proves that various inorganic or organic materials can be used as the core, and different types of nucleic acids can be conjugated to realize diverse functions and achieve surprising and exciting outcomes. The special DNA nanostructures have been employed for immunomodulation, gene regulation, drug delivery, biosensing, and bioimaging. Despite the lack of rational design strategies, potential cytotoxicity, and structural defects of this technology, various successful examples demonstrate the bright and convincing future of SNAs in fields such as new materials, clinical practice, and pharmacy.

Polymeric Nanoparticles for Drug Delivery

The recent emergence of nanomedicine has revolutionized the therapeutic landscape and necessitated the creation of more sophisticated drug delivery systems. Polymeric nanoparticles sit at the forefront of numerous promising drug delivery designs, due to their unmatched control over physiochemical properties such as size, shape, architecture, charge, and surface functionality. Furthermore, polymeric nanoparticles have the ability to navigate various biological barriers to precisely target specific sites within the body, encapsulate a diverse range of therapeutic cargo and efficiently release this cargo in response to internal and external stimuli. However, despite these remarkable advantages, the presence of polymeric nanoparticles in wider clinical application is minimal. This review will provide a comprehensive understanding of polymeric nanoparticles as drug delivery vehicles. The biological barriers affecting drug delivery will be outlined first, followed by a comprehensive description of the various nanoparticle designs and preparation methods, beginning with the polymers on which they are based. The review will meticulously explore the current performance of polymeric nanoparticles against a myriad of diseases including cancer, viral and bacterial infections, before finally evaluating the advantages and crucial challenges that will determine their wider clinical potential in the decades to come.

A fully biodegradable spherical nucleic acid nanoplatform for self-codelivery of doxorubicin and miR122 for innate and adaptive immunity activation

Facile construction of a fully biodegradable spherical nucleic acid (SNA) nanoplatform is highly desirable for clinical translations but remains rarely explored. We developed herein the first polycarbonate-based biodegradable SNA nanoplatform for self-codelivery of a chemotherapeutic drug, doxorubicin (DOX), and a human liver-specific miR122 for synergistic chemo-gene therapy of hepatocellular carcinoma (HCC). Ring-opening polymerization (ROP) of a carbonate monomer leads to a well-defined polycarbonate backbone for subsequent DOX conjugation to the pendant side chains via acidic pH-cleavage Schiff base links and miR122 incorporation to the chain termini via click coupling, affording an amphiphilic polycarbonate-DOX-miR122 conjugate, PBis-Mpa30-DOX-miR122 that can self-assemble into stabilized SNA. Besides the desired biodegradability, another notable merit of this nanoplatform is the use of miR122 not only for gene therapy but also for enhanced innate immune response. Together with the ICD-triggering effect of DOX, PBis-Mpa30-DOX-miR122 SNA-mediated DOX and miR122 codelivery leads to synergistic immunogenicity enhancement, resulting in tumor growth inhibition value (TGI) of 98.1 % significantly higher than those of the groups treated with only drug or gene in a Hepa1-6-tumor-bearing mice model. Overall, this study develops a useful strategy toward biodegradable SNA construction, and presents a drug and gene-based self-codelivery SNA with synergistic immunogenicity enhancement for efficient HCC therapy. STATEMENT OF SIGNIFICANCE: Facile construction of a fully biodegradable SNA nanoplatform is useful for in vivo applications but remains relatively unexplored likely due to the synthetic challenge. We report herein construction of a polycarbonate-based SNA nanoplatform for co-delivering a chemotherapeutic drug, DOX, and a human liver-specific miR-122 for synergistic HCC treatment. In addition to the desired biodegradability properties, this SNA nanoplatform integrates DOX-triggered ICD and miR-122-enhanced innate immunity for simultaneously activating adaptive and innate immunities, which leads to potent antitumor efficiency with a TGI value of 98.1 % in a Hepa1-6-tumor-bearing mice model.

Bioinspired and biomimetic strategies for inflammatory bowel disease therapy

Inflammatory bowel disease (IBD) is an idiopathic chronic inflammatory bowel disease with high morbidity and an increased risk of cancer or death, resulting in a heavy societal medical burden. While current treatment modalities have been successful in achieving long-term remission and reducing the risk of complications, IBD remains incurable. Nanomedicine has the potential to address the high toxic side effects and low efficacy in IBD treatment. However, synthesized nanomedicines typically exhibit some degree of immune rejection, off-target effects, and a poor ability to cross biological barriers, limiting the development of clinical applications. The emergence of bionic materials and bionic technologies has reshaped the landscape in novel pharmaceutical fields. Biomimetic drug-delivery systems can effectively improve biocompatibility and reduce immunogenicity. Some bioinspired strategies can mimic specific components, targets or immune mechanisms in pathological processes to produce targeting effects for precise disease control. This article highlights recent research on bioinspired and biomimetic strategies for the treatment of IBD and discusses the challenges and future directions in the field to advance the treatment of IBD.

Spherical nucleic acids: emerging amplifiers for therapeutic nanoplatforms

Gene therapy is a revolutionary treatment approach in the 21st century, offering significant potential for disease prevention and treatment. However, the efficacy of gene delivery is often compromised by the inherent challenges of gene properties and vector-related defects. It is crucial to explore ways to enhance the curative effect of gene drugs and achieve safer, more widespread, and more efficient utilization, which represents a significant challenge in amplification gene therapy advancements. Spherical nucleic acids (SNAs), with their unique physicochemical properties, are considered an innovative solution for scalable gene therapy. This review aims to comprehensively explore the amplifying contributions of SNAs in gene therapy and emphasize the contribution of SNAs to the amplification effect of gene therapy from the aspects of structure, application, and recent clinical translation - an aspect that has been rarely reported or explored thus far. We begin by elucidating the fundamental characteristics and scaling-up properties of SNAs that distinguish them from traditional linear nucleic acids, followed by an analysis of combined therapy treatment strategies, theranostics, and clinical translation amplified by SNAs. We conclude by discussing the challenges of SNAs and provide a prospect on the amplification characteristics. This review seeks to update the current understanding of the use of SNAs in gene therapy amplification and promote further research into their clinical translation and amplification of gene therapy.

Dynamic Light Scattering of DNA-Ligand Complexes

Dynamic light scattering (DLS) enables the characterization of sizes and electrokinetic properties of colloids, polymers, and macromolecules. DNA is a charged semiflexible polyelectrolyte that is condensed or compacted by counterions, proteins, and other condensing agents in processes such as chromosome compaction and gene therapeutic applications. DNA condensation is closely related to charge screening since packaging requires effective neutralization of its surface negative charges. In this chapter, we describe in detail the protocol for DLS DNA-ligand complexes. As an example, we describe data for the condensation of DNA by chitosan and the measurement of size, zeta potential, and electrophoretic mobility of the DNA-ligand complex by DLS.

Endogenous Enzyme-Activatable Spherical Nucleic Acids for Spatiotemporally Controlled Signal Amplification Molecular Imaging and Combinational Tumor Therapy

Due to the adjustable hybridization activity, antinuclease digestion stability, and superior endocytosis, spherical nucleic acids (SNAs) have been actively developed as probes for molecular imaging and the development of noninvasive diagnosis and image-guided surgery. However, since highly expressed biomarkers in tumors are not negligible in normal tissues, an inevitable background signal and the inability to precisely release probes at the chosen region remain a challenge for SNAs. Herein, we proposed a rationally designed, endogenous enzyme-activatable functional SNA (Ep-SNA) for spatiotemporally controlled signal amplification molecular imaging and combinational tumor therapy. The self-assembled amphiphilic polymer micelles (SM-ASO), which were obtained by a simple and rapid copper-free strain-promoted azide-alkyne cycloaddition click reaction between dibenzocyclooctyne-modified antisense oligonucleotide and azide-containing aliphatic polymer polylactic acid, were introduced as the core elements of Ep-SNA. This Ep-SNA was then constructed by connecting two apurinic/apyrimidinic (AP) site-containing trailing DNA hairpins, which could occur via a hybridization chain reaction in the presence of low-abundance survivin mRNA to SM-ASO through complementary base pairing. Notably, the AP site-containing trailing DNA hairpins also empowered the SNA with the feasibility of drug delivery. Once this constructed intelligent Ep-SNA nanoprobe was specifically cleaved by the highly expressed cytoplasmic human apurinic/apyrimidinic endonuclease 1 in tumor cells, three key elements (trailing DNA hairpins, antisense oligonucleotide, and doxorubicin) could be released to enable subsequent high-sensitivity survivin mRNA imaging and combinational cancer therapy (gene silencing and chemotherapy). This strategy shows great application prospects of SNAs as a precise platform for the integration of disease diagnosis and treatment and can contribute to basic biomedical research.

Spherical nucleic acids-based nanoplatforms for tumor precision medicine and immunotherapy

Precise diagnosis and treatment of tumors currently still face considerable challenges due to the development of highly degreed heterogeneity in the dynamic evolution of tumors. With the rapid development of genomics, personalized diagnosis and treatment using specific genes may be a robust strategy to break through the bottleneck of traditional tumor treatment. Nevertheless, efficient in vivo gene delivery has been frequently hampered by the inherent defects of vectors and various biological barriers. Encouragingly, spherical nucleic acids (SNAs) with good modularity and programmability are excellent candidates capable of addressing traditional gene transfer-associated issues, which enables SNAs a precision nanoplatform with great potential for diverse biomedical applications. In this regard, there have been detailed reviews of SNA in drug delivery, gene regulation, and dermatology treatment. Still, to the best of our knowledge, there is no published systematic review summarizing the use of SNAs in oncology precision medicine and immunotherapy, which are considered new guidelines for oncology treatment. To this end, we summarized the notable advances in SNAs-based precision therapy and immunotherapy for tumors following a classification standard of different types of precise spatiotemporal control on active species by SNAs. Specifically, we focus on the structural diversity and programmability of SNAs. Finally, the challenges and possible solutions were discussed in the concluding remarks. This review will promote the rational design and development of SNAs for tumor-precise medicine and immunotherapy.

Magnetic Bead Spherical Nucleic Acid Microstructure for Reliable DNA Preservation and Repeated DNA Reading

DNA is an attractive medium for long-term data storage because of its density, ease of copying, sustainability, and longevity. Recent advances have focused on the development of new encoding algorithms, automation, and sequencing technologies. Despite progress in these subareas, the most challenging hurdle in the deployment of DNA storage remains the reliability of preservation and the repeatability of reading. Herein, we report the construction of a magnetic bead spherical nucleic acid (MB-SNA) composite microstructure and its use as a cost-effective platform for reliable DNA preservation and repeated reading. MB-SNA has an inner core of silica@γ-Fe2O3@silica microbeads and an outer spherical shell of double-stranded DNA (dsDNA) with a density as high as 34 pmol/cm2. For MB-SNA, each strand of dsDNA stored a piece of data, and the high-density packing of dsDNA achieved high-capacity storage. MB-SNA was advantageous in terms of reliable preservation over free DNA. By accelerated aging tests, the data of MB-SNA is demonstrated to be readable after 0.23 million years of preservation at -18 °C and 50% relative humidity. Moreover, MB-SNA facilitated repeated reading by facile PCR-magnetic separation. After 10 cycles of PCR access, the retention rate of dsDNA for MB-SNA is demonstrated to be as high as 93%, and the accuracy of sequencing is more than 98%. In addition, MB-SNA makes cost-effective DNA storage feasible. By serial dilution, the physical limit for MB-SNA to achieve accurate reading is probed to be as low as two microstructures.

DNA Nanomaterials-Based Platforms for Cancer Immunotherapy

The past few decades have witnessed the evolving paradigm for cancer therapy from nonspecific cytotoxic agents to selective, mechanism-based therapeutics, especially immunotherapy. In particular, the integration of nanomaterials with immunotherapy is proven to improve the therapeutic outcome and minimize off-target toxicity in the treatment. As a novel nanomaterial, DNA-based self-assemblies featuring uniform geometries, feasible modifications, programmability, surface addressability, versatility, and intrinsic biocompatibility, are extensively exploited for innovative and effective cancer immunotherapy. In this review, the successful employment of DNA nanoplatforms for cancer immunotherapy, including the delivery of immunogenic cell death inducers, adjuvants and vaccines, immune checkpoint blockers as well as the application in immune cell engineering and adoptive cell therapy is summarized. The remaining challenges and future perspectives regarding the pharmacokinetics/pharmacodynamics, in vivo fate and immunogenicity of DNA materials, and the design of intelligent DNA nanomedicine for individualized cancer immunotherapy are also discussed.

Programming the dynamic range of nanobiosensors with engineering poly-adenine-mediated spherical nucleic acid

Spherical nucleic acid (SNA) conjugates consisting of gold cores functionalized with a densely packed DNA shells are of great significance in the field of medical detection and intracellular imaging. Especially, poly adenine (polyA)-mediated SNAs can improve the controllability and reproducibility of DNA assembly on the nanointerface, showing the tunable hybridization ability. However, due to the physics of single-site binding, the biosensor based on SNA usually exhibits a dynamic range spanning a fixed 81-fold change in target concentration, which limits its application in disease monitoring. To address this problem, we report a tri-block DNA-based approach to assemble SNA for nucleic acid detection based on structure-switching mechanism with programmable dynamic range. The tri-block DNA is a FAM-labeled stem-loop structure, which contains three blocks: polyA block as an anchoring block for tunable surface density, stem block with different GC base pair content for varying the structure stability, and the fixed loop block for target recognition. We find that varying the polyA block, the reaction temperature, and the GC base pair, SNA shows different target binding affinity and detection limit but with normally 81-fold dynamic range. We can extend the dynamic range to 1000-fold by using the combination of two SNAs with different affinity, and narrow the dynamic range to 5-fold by sequestration mechanism. Furthermore, the tunable SNA enables sensitive detection of mRNA in cells. Given its tunable dynamic range, such nanobiosensor based on SNA offers new possibility for various biomedical and clinical applications.

Dendronized DNA Chimeras Harness Scavenger Receptors To Degrade Cell Membrane Proteins

Bispecific chimeras bridging cell membrane proteins with lysosome-trafficking receptors (LTRs) provide an effective therapeutic approach through lysosomal degradation of disease-relevant targets. Here, we report a novel dendronized DNA chimera (DENTAC) strategy that uses a dendritic DNA to engage cell surface scavenger receptors (SRs) as LTR. Using bioorthogonal strain-promoted alkyne-azide cycloaddition to conjugate the dendritic DNA with protein binder, the resulting DENTAC is able to traffic the protein target into the lysosome for elimination. We demonstrated the utility of DENTAC by degrading oncogenic membrane nucleolin (NCL) and epidermal growth factor receptor (EGFR). The anti-cancer application of NCL-targeting DENTAC was validated in a mouse xenograft model of lung cancer. This work thus presents a new avenue for rapid development of potent degraders against membrane proteins, with also broad research and therapeutic prospects.

Cancer-cell-membrane-camouflaged supramolecular self-assembly of antisense oligonucleotide and chemodrug for targeted combination therapy

The anti-apoptotic B-cell lymphoma-2 (Bcl-2) family of proteins are critical regulators of cell death that are overexpressed in many cancer cells, especially in multi-drug resistant cancer cells. Combinatorial gene- and chemotherapies using antisense oligonucleotides (ASOs) to suppress the expression of Bcl-2-family mRNA and restore the sensitivity of the cell to chemodrugs provide a promising pathway for anticancer treatment. However, intrinsic differences between macromolecular ASOs and small molecular chemodrugs make their co-delivery challenging. Moreover, extraneous carriers may induce immunogenicity and inflammation problems. Herein, we develop a targeted nanodrug delivery system using the cationic amphiphilic chemodrug mitoxantrone (Mito), which interacts with Bcl-2 ASO through electrostatic interaction and self-assembles into nanoparticles (NP_[Bcl-2/Mito]), whose size can be controlled by regulating the ratio of ASO and Mito. NP_[Bcl-2/Mito] can protect the ASO from degradation during delivery and combine gene- and chemotherapies to improve the anticancer effect. Furthermore, cancer cell membranes (CCMs) derived from homologous tumors were used to camouflage NP_[Bcl-2/Mito] (NP_[Bcl-2/Mito]@CCM) to achieve immune escape and tumor targeting. Both in vitro and in vivo assessments demonstrate the excellent performance of NP_[Bcl-2/Mito]@CCM for drug-resistant breast tumor therapy. This CCM-camouflaged ASO/chemodrug nanoplatform provides a promising pathway for the targeted delivery of ASOs and chemodrugs for tumor combination therapy.

PD-L1 Aptamer-Functionalized Metal-Organic Framework Nanoparticles for Robust Photo-Immunotherapy against Cancer with Enhanced Safety

Immune checkpoint blockade has become a paradigm-shifting treatment modality to combat cancer, while conventional administration of immune checkpoint inhibitors, such as anti-PD-L1 antibody (α-PD-L1), often shows unsatisfactory immune responses and lead to severe immune-related adverse effects (irAEs). Herein, we develop a PD-L1 aptamer-based spherical nucleic acids (SNAs), which consists of oxaliplatin (OXA) encapsulated in a metal-organic framework nanoparticle core and a dense shell of aptPD-L1 (denoted as M@O-A). Upon light irradiation, this nanosystem enables concurrent photodynamic therapy (PDT), chemotherapy, and enhanced immunotherapy in one shot to inhibit both primary colorectal tumors and untreated distant tumors in mice. Notably, M@O-A shows scarcely any systemic immunotoxicity in a clinical irAEs-mimic transgenic mouse model. Collectively, this study presents a novel strategy for priming robust photo-immunotherapy against cancer with enhanced safety.

A dynamic DNA tetrahedron framework for active targeting

An active targeting strategy-enabled DNA tetrahedron delivery vehicle could facilitate stable drug encapsulation and stimuli-responsive on-demand release, building a universal platform for different drug delivery requirements. Owing to the excellent biocompatible nature, programmability and remarkable cell and tissue permeability, the tetrahedral DNA nanostructure (TDN) has proven its value in the delivery of various bioactive molecules. We previously described this as a static multifunctional complex in our earlier protocol. However, static structures and passive targeting behavior might introduce off-target effects under complicated biological conditions. Therefore, in this Protocol Extension, we present a major update of the TDN delivery vehicle enabling an active targeting strategy to be used for stimuli-sensitive conformation changes and on-site cargo release, which could avoid drawbacks, including complex and time-consuming fabrication processes and undetermined cell penetration ability of other DNA-based delivery vehicles. Upon exquisite design of TDN size based on cargo type, one-pot annealing is applied to fabricate the Tiamat-designed TDN exoskeleton. Then the design of the dynamic DNA apparatus can be based on the target and environmental stimuli, including DNA strand hybridization-based and pH-sensitive DNA apparatus, and careful titration of strand lengths and mismatches is achieved using polyacrylamide and agarose gel electrophoresis, or fluorophore modifications. Finally, cargo loading strategies are designed, including site and stand titration and cargo encapsulation verification. The dynamic structures show promising targetability and effectiveness in antitumor and anti-inflammatory treatment in vitro and in vivo. Assembly and characterization in the lab takes ~5 d, and the timing for the verification of biostability and biological applications depends on the uses.

An MMP-2 sensitive and reduction-responsive prodrug amphiphile for actively targeted therapy of cancer by hierarchical cleavage

A hierarchically cleaved amphiphile, mPEG-pep-etcSS-CPT, was synthesized to pursue actively targeted cancer therapy through self-assembly. This micelle can respond to MMP-2 achieving dePEGylation and releasing RGD peptides to be internalized into targetable tumor cells. Inside the cell, free CPT could be released by reduction-response leading to cytotoxicity.

Lysosomal-mediated drug release and activation for cancer therapy and immunotherapy

The development of carrier systems that are able to transport and release therapeutics to target cells is an emergent strategy to treat cancer; however, they following endocytosis are usually trapped in the endo/lysosomal compartments. The efficacy of drug conjugates and nanotherapeutics relies critically on their intracellular drug release ability, for which advanced systems responding to the unique lysosomal environment such as acidic pH and abundant enzymes (e.g. cathepsin B, sulfatase and β-glucuronidase) or equipped with photochemical internalization property have been energetically pursued. In this review, we highlight the recent designs of smart systems that promote efficient lysosomal release and/or escape of anticancer agents including chemotherapeutics (e.g. doxorubicin, platinum, chloroquine and hydrochloroquine) and biotherapeutics (e.g. proteins, siRNA, miRNA, mRNA and pDNA) to cancer cells or immunotherapeutic agents (e.g. antigens, mRNA and immunoadjuvants) to antigen-presenting cells (APCs), thereby boosting cancer therapy and immunotherapy. Lysosomal-mediated drug release presents an appealing approach to develop innovative cancer therapeutics and immunotherapeutics.

Design of Cyclic Peptide-Based Nanospheres and the Delivery of siRNA

In recent years, cyclic peptides have attracted much attention due to their chemical and enzymatic stability, low toxicity, and easy modification. In general, the self-assembled nanostructures of cyclic peptides tend to form nanotubes in a cyclic stacking manner through hydrogen bonding. However, studies exploring other assembly strategies are scarce. In this context, we proposed a new assembly strategy based on cyclic peptides with covalent self-assembly. Here, cyclic peptide-(DPDPDP) was rationally designed and used as a building block to construct new assemblies. With cyclo-(DP)₃ as the structural unit and 2,2′-diamino-N-methyldiethylamine as the linker, positively charged nanospheres ((CP)₆NS) based on cyclo-(DP)₃ were successfully constructed by covalent self-assembly. We assessed their size and morphology by scanning electron microscopy (SEM), TEM, and DLS. (CP)₆NS were found to have a strong positive charge, so they could bind to siRNA through electrostatic interactions. Confocal microscopy analysis and cell viability assays showed that (CP)₆NS had high cellular internalization efficiency and low cytotoxicity. More importantly, real-time polymerase chain reaction (PCR) and flow cytometry analyses indicated that (CP)₆NS-siRNA complexes potently inhibited gene expression and promoted tumor cell apoptosis. These results suggest that (CP)₆NS may be a potential siRNA carrier for gene therapy.

Nucleic acid-based supramolecular structures: vesicular spherical nucleic acids from a non-phospholipid nucleolipid

Vesicular spherical nucleic acids are dynamic nucleic acid-based supramolecular structures that are held together via non-covalent bonds. They have promising applications as drug and nucleic acid delivery materials, diagnostic and imaging tools and platforms for development of various therapeutic schemes. In this contribution, we report on vesicular spherical nucleic acids, constructed from a non-phospholipid nucleolipid - an original hybrid biomacromolecule, composed of a hydrophobic residue, resembling that of the naturally occurring phospholipids, and a DNA oligonucleotide strand. The nucleolipid was synthesized by coupling of dibenzocyclooctyne-functionalized oligonucleotide and azidated 1,3-dihexadecyloxy-propane-2-ol via an azide-alkyne click reaction. In aqueous solution it spontaneously self-associated into nanosized supramolecular structures, identified as unilamellar vesicles composed of a self-closed interdigitated bilayer. Vesicular structures were also formed upon intercalation of the nucleolipid via its lipid-mimetic residue in the phospholipid bilayer membrane of liposomes prepared from readily available and FDA-approved lipids (1,2-dipalmitoyl-rac-glycero-3-phosphocholine and cholesterol). The vesicular structures are thoroughly investigated by light scattering (dynamic, static, and electrophoretic) and cryogenic TEM and the physical characteristics, in particular, number of strands per particle, grafting density, and conformation of the strands, were compared to those of reference spherical nucleic acids. Finally, the vesicular structures were shown to exhibit cellular internalization with no need of transfection agents and enhanced colloidal and nuclease stability.

A stable DNA Tetrahedra-AuNCs nanohybrid: On-site programmed disassembly for tumor imaging and combination therapy

Despite DNA nanotechnology has spawned a broad variety and taken a giant leap toward cancer theranostic applications over the last decade, the homogeneous DNA nanostructures often suffer from fatal degradation due to their limited stability and specificity. Herein, for the first time, we report a stable DNA tetrahedra-gold nanoclusters (DT/AuNCs) nanohybrid with a self-assembly/programmed disassembly manner for stimuli-responsive tumor imaging and gene-chemo therapy. By utilizing the multifunctional peptides with positive and legumain-specific domains as bioligands, AuNCs were synthesized as signal generators and gate guard attached on the dual-responsive DT, forming the DT/AuNCs with sequential response to legumain-TK1 mRNA & glutathione. The tumorous biomarker of legumain initiated the signal generation relying on the nanosurface energy transfer effect of AuNCs and denudation of DT-Dox (preliminary disassembly). Successively, the dual-responsive DT-Dox administrated a sequential fragmentation along with Dox release in response to the up-regulated glutathione and TK1 mRNA (secondary disassembly), thereby leading to combined gene silencing and chemo-therapy. The results revealed that the DT/AuNCs nanohybrids significantly improved the stability and enhanced the therapeutic efficiency compared to naked DT. Endowing with remarkable stability against biological milieu and site specificity for drug release, our work exhibits a new prospect of fabricating DNA-based nanohybrids for precise tumor theranostics.

Hollow spherical nucleic acid structures based on polymer-coated phospholipid vesicles

A feasible one pot synthesis of hollow spherical nucleic acids (SNAs) using phospholipid liposomes is reported. These constructs are synthesized in a chemically straightforward process involving formation of unilamellar liposomes, coating the liposomes with a thin cross-linked polymeric layer, and grafting the latter with short (about 20 bases) DNA oligonucleotide strands. They consist of vesicular cores, composed of readily available phospholipid (1,2-dipalmitoyl-sn-glycero-phosphocholine), whereas the strands are deliberately arranged on the surface of the vesicular entities. The initial vesicular structure and morphology are preserved during the coating and grafting reactions. The novel hollow/vesicular SNAs are characterized with a hydrodynamic radius and radius of gyration of 78.3 and 88.5 nm, respectively, and moderately negative (-14.2 mV) ζ potential. They carry thousands (5868) of oligonucleotide strands per vesicle, which are not strongly radially oriented and adopt an unextended conformation as anticipated from the smaller value of the grafting density compared to the critical grafting density at the transition to brush conformation. The constructs are practically devoid of toxicity and exhibit high binding affinity to complementary nucleic acids. Unlike any other nucleic acid structural motif, they cross the cell membrane and enter cells without the need of transfection agents.

Supramolecular-mediated dual-functional DNA nanocomposites for programmable cancer therapy

Programmable cancer therapies may perfectly prevent mutual drug restrictions, however, developing an efficient codelivery system with such an ability remains challenging. We herein first demonstrate the use of supramolecular-mediated dual-functional DNA nanocomposites for programmable chemodynamic therapy (CDT) and chemotherapy (CT), in which a water-soluble cyclodextrin-resveratrol (CD-Res) complex can be facilely encapsulated during the coassembly of Fe²⁺ and DNA to form the desired spherical nanocomposites. After endocytosis, the released Fe²⁺ can immediately trigger an endogenous Fenton reaction, inducing ferroptosis for CDT and ˙OH depletion, followed by the sustained release of the protected Res from the CD cavity. This process improves the efficacy of CT by preventing Res from the oxidation of ˙OH. The as-prepared nano-composites can sufficiently accumulate in the tumor, demonstrating an adequate programmable therapeutic performance without serious toxicity. Thus, a facile, fresh and changeable strategy for the design of antitumor therapies is presented.

Amplification of the Fluorescence Signal with Clustered Regularly Interspaced Short Palindromic Repeats-Cas12a Based on Au Nanoparticle-DNAzyme Probe and On-Site Detection of Pb2+ Via the Photonic Crystal Chip

Although great headway has been made in DNAzyme-based detection of Pb²⁺, its adaptability, sensitivity, and accessibility in complex media still need to be improved. For this, we introduce new ways to surmount these hurdles. First, a spherical nucleic acid (SNA) fluorescence probe (Au nanoparticles-DNAzyme probe) is utilized to specifically identify Pb²⁺ and its suitability for precise detection of Pb²⁺ in complex samples due to its excellent nuclease resistance. Second, the sensitivity of Pb²⁺ detection is greatly enhanced via the use of a clustered regularly interspaced short palindromic repeats-Cas12a with target recognition accuracy to amplify the fluorescent signal upon the trans cleavage of the SNA (signal probe), and the limit of detection reaches as low as 86 fM. Third, we boost the fluorescence on photonic crystal chips with a bionic periodic arrangement by employing a straightforward detection device (smartphone and portable UV lamp) to achieve on-site detection of Pb²⁺ with the limit of detection as low as 24 pM. Based on the abovementioned efforts, the modified Pb²⁺ fluorescence sensor has the advantages of higher sensitivity, better specificity, accessibility, less sample consumption, and so forth. Moreover, it can be applied to accurately detect Pb²⁺ in complex biological or environmental samples, which is of great promise for widespread applications.

Maximizing TLR9 Activation in Cancer Immunotherapy with Dual-Adjuvanted Spherical Nucleic Acids

Nucleic-acid-based immune adjuvants have been extensively investigated for the design of cancer vaccines. However, nucleic acids often require the assistance of a carrier system to improve cellular uptake. Yet, such systems are prone to carrier-associated adaptive immunity, leading to difficulties in a multidose treatment regimen. Here, we demonstrate that a spherical nucleic acid (SNA)-based self-adjuvanting system consisting of phosphodiester oligonucleotides and vitamin E can function as a potent anticancer vaccine without a carrier. The two functional modules work synergistically, serving as each other's delivery vector to enhance toll-like receptor 9 activation. The vaccine rapidly enters cells carrying OVA model antigens, which enables efficient activation of adaptive immunity in vitro and in vivo. In OVA-expressing tumor allograft models, both prophylactic and therapeutic vaccinations significantly retard tumor growth and prolong animal survival. Furthermore, the vaccinations were also able to reduce lung metastasis in a B16F10-OVA model.

Copackaging photosensitizer and PD-L1 siRNA in a nucleic acid nanogel for synergistic cancer photoimmunotherapy

Packaging multiple drugs into a nanocarrier with rational design to achieve synergistic cancer therapy remains a challenge due to the intrinsically varied pharmacodynamics of therapeutic agents. Especially difficult is combining small-molecule drugs and macromolecular biologics. Here, we successfully graft pheophorbide A (PPA) photosensitizers on DNA backbone at predesigned phosphorothioate modification sites. The synthesized four PPA-grafted DNAs are assembled into a tetrahedron framework, which further associates with a programmed death ligand-1 (PD-L1) small interfering RNA (siRNA) linker through supramolecular self-assembly to form an siRNA and PPA copackaged nanogel. With dual therapeutic agents inside, the nanogel can photodynamically kill tumor cells and induce remarkable immunogenic cell death. Also, it simultaneously silences the PD-L1 expression of the tumor cells, which substantially promotes the antitumor immune response and leads to an enhanced antitumor efficacy in a synergistic fashion.

Carrier-Free Nanomedicine for Cancer Immunotherapy

With the rapid development of nanotechnology, carrier-based nano-drug delivery systems (DDSs) have been widely studied due to their advantages in optimizing pharmacokinetic and distribution profiles. However, despite those merits, some carrier-related limitations, such as low drug-loading capacity, systematic toxicity and unclear metabolism, usually prevent their further clinical transformation. Carrier-free nanomedicines with non-therapeutic excipients, are considered as an excellent paradigm to overcome these obstacles, owing to their superiority in improving both drug delivery efficacy and safety concern. In recent years, carrier-free nanomedicines have opened new horizons for cancer immunotherapy, and have already made outstanding progress. Herein, in this review, we are focusing on making an integrated and exhaustive overview of lately reports about them. Firstly, the major synthetic strategies of carrier-free nanomedicines are introduced, such as nanocrystals, prodrug-, amphiphilic drug-drug conjugates (ADDCs)-, polymer-drug conjugates-, and peptide-drug conjugates (PepDCs)-assembled nanomedicines. Afterwards, the typical applications of carrier-free nanomedicines in cancer immunotherapy are well-discussed, including cancer vaccines, cytokine therapy, enhancing T-cell checkpoint inhibition, as well as modulating tumor microenvironment (TME). After that, both the advantages and the potential challenges, as well as the future prospects of carrier-free nanomedicines in cancer immunotherapy, were discussed. And we believe that it would be of great potential practiced and reference value to the relative fields.

Multivalent Aptamer Approach: Designs, Strategies, and Applications

Aptamers are short and single-stranded DNA or RNA molecules with highly programmable structures that give them the ability to interact specifically with a large variety of targets, including proteins, cells, and small molecules. Multivalent aptamers refer to molecular constructs that combine two or more identical or different types of aptamers. Multivalency increases the avidity of aptamers, a particularly advantageous feature that allows for significantly increased binding affinities in comparison with aptamer monomers. Another advantage of multivalency is increased aptamer stabilities that confer improved performances under physiological conditions for various applications in clinical settings. The current study aims to review the most recent developments in multivalent aptamer research. The review will first discuss structures of multivalent aptamers. This is followed by detailed discussions on design strategies of multivalent aptamer approaches. Finally, recent developments of the multivalent aptamer approach in biosensing and biomedical applications are highlighted.

Smart Drug Delivery Systems Based on DNA Nanotechnology

The development of DNA nanotechnology has attracted tremendous attention in biotechnological and biomedical fields involving biosensing, bioimaging and disease therapy. In particular, precise control over size and shape, easy modification, excellent programmability and inherent homology make the sophisticated DNA nanostructures vital for constructing intelligent drug carriers. Recent advances in the design of multifunctional DNA-based drug delivery systems (DDSs) have demonstrated the effectiveness and advantages of DNA nanostructures, showing the unique benefits and great potential in enhancing the delivery of pharmaceutical compounds and reducing systemic toxicity. This Review aims to overview the latest researches on DNA nanotechnology-enabled nanomedicine and give a perspective on their future opportunities.

Paclitaxel Drug Delivery Systems: Focus on Nanocrystals' Surface Modifications

Paclitaxel (PTX) is a chemotherapeutic agent that belongs to the taxane family and which was approved to treat various kinds of cancers including breast cancer, ovarian cancer, advanced non-small-cell lung cancer, and acquired immunodeficiency syndrome (AIDS)-related Kaposi’s sarcoma. Several delivery systems for PTX have been developed to enhance its solubility and pharmacological properties involving liposomes, nanoparticles, microparticles, micelles, cosolvent methods, and the complexation with cyclodextrins and other materials that are summarized in this article. Specifically, this review discusses deeply the developed paclitaxel nanocrystal formulations. As PTX is a hydrophobic drug with inferior water solubility properties, which are improved a lot by nanocrystal formulation. Based on that, many studies employed nano-crystallization techniques not only to improve the oral delivery of PTX, but IV, intraperitoneal (IP), and local and intertumoral delivery systems were also developed. Additionally, superior and interesting properties of PTX NCs were achieved by performing additional modifications to the NCs, such as stabilization with surfactants and coating with polymers. This review summarizes these delivery systems by shedding light on their route of administration, the methods used in the preparation and modifications, the in vitro or in vivo models used, and the advantages obtained based on the developed formulations.

Spherical nucleic acids: Organized nucleotide aggregates as versatile nanomedicine

Spherical nucleic acids (SNAs) are composed of a nanoparticle core and a layer of densely arranged oligonucleotide shells. After the first report of SNA by Mirkin and coworkers in 1996, it has created a significant interest by offering new possibilities in the field of gene and drug delivery. The controlled aggregation of oligonucleotides on the surface of organic/inorganic nanoparticles improves the delivery of genes and nucleic acid-based drugs and alters and regulates the biological profiles of the nanoparticle core within living organisms. Here in this review, we present an overview of the recent progress of SNAs that has speeded up their biomedical application and their potential transition to clinical use. We start with introducing the concept and characteristics of SNAs as drug/gene delivery systems and highlight recent efforts of bioengineering SNA by imaging and treatmenting various diseases. Finally, we discuss potential challenges and opportunities of SNAs, their ongoing clinical trials, and future translation, and how they may affect the current landscape of clinical practices. We hope that this review will update our current understanding of SNA, organized oligonucleotide aggregates, for disease diagnosis and treatment.

Erythrocyte membrane camouflaged siRNA/chemodrug nanoassemblies for cancer combination therapy

Erythrocyte membrane camouflaged nanoassemblies of siRNA/chemodrugs were constructed, in which cationic amphiphilic chemodrugs interact with negatively charged siRNA and self-assemble into siRNA/chemodrug nanoparticles for combination cancer therapy.

Self-Protected DNAzyme Walker with a Circular Bulging DNA Shield for Amplified Imaging of miRNAs in Living Cells and Mice

Abnormal expression of miRNAs is often detected in various human cancers. DNAzyme machines combined with gold nanoparticles (AuNPs) hold promise for detecting specific miRNAs in living cells but show short circulation time due to the fragility of catalytic core. Using miRNA-21 as the model target, by introducing a circular bulging DNA shield into the middle of the catalytic core, we report herein a self-protected DNAzyme (E) walker capable of fully stepping on the substrate (S)-modified AuNP for imaging intracellular miRNAs. The DNAzyme walker exhibits 5-fold enhanced serum resistance and more than 8-fold enhanced catalytic activity, contributing to the capability to image miRNAs much higher than commercial transfection reagent and well-known FISH technique. Diseased cells can accurately be distinguished from healthy cells. Due to its universality, DNAzyme walker can be extended for imaging other miRNAs only by changing target binding domain, indicating a promising tool for cancer diagnosis and prognosis.

Molecularly pure miktoarm spherical nucleic acids: preparation and usage as a scaffold for abiotic intracellular catalysis

We present a fullerene-based strategy that allows the synthesis of molecularly pure miktoarm spherical nucleic acids (SNAs) with diverse structures, which, with post-functionalization, could serve as efficient scaffolds for intracellular catalysis. The SNA structure promotes cell permeability, nucleic acid stability, and catalytic efficiency, making the platform ideal for in cellulo reactions. Consequently, the tris(triazole)-bearing miktoarm SNA was able to effectively mediate intracellular copper-catalyzed alkyne-azide cycloaddition at nanomolar level of copper, and facilitate the same reaction in live zebrafish.

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.

Cation-Free siRNA Micelles as Effective Drug Delivery Platform and Potent RNAi Nanomedicines for Glioblastoma Therapy

Nanoparticle-based small interfering RNA (siRNA) therapy shows great promise for glioblastoma (GBM). However, charge associated toxicity and limited blood-brain-barrier (BBB) penetration remain significant challenges for siRNA delivery for GBM therapy. Herein, novel cation-free siRNA micelles, prepared by the self-assembly of siRNA-disulfide-poly(N-isopropylacrylamide) (siRNA-SS-PNIPAM) diblock copolymers, are prepared. The siRNA micelles not only display enhanced blood circulation time, superior cell take-up, and effective at-site siRNA release, but also achieve potent BBB penetration. Moreover, due to being non-cationic, these siRNA micelles exert no charge-associated toxicity. Notably, these desirable properties of this novel RNA interfering (RNAi) nanomedicine result in outstanding growth inhibition of orthotopic U87MG xenografts without causing adverse effects, achieving remarkably improved survival benefits. Moreover, as a novel type of polymeric micelle, the siRNA micelle displays effective drug loading ability. When utilizing temozolomide (TMZ) as a model loading drug, the siRNA micelle realizes effective synergistic therapy effect via targeting the key gene (signal transducers and activators of transcription 3, STAT3) in TMZ drug resistant pathways. The authors' results show that this siRNA micelle nanoparticle can serve as a robust and versatile drug codelivery platform, and RNAi nanomedicine and for effective GBM treatment.

Functional DNA-Polymer Conjugates

DNA nanotechnology has seen large developments over the last 30 years through the combination of solid phase synthesis and the discovery of DNA nanostructures. Solid phase synthesis has facilitated the availability of short DNA sequences and the expansion of the DNA toolbox to increase the chemical functionalities afforded on DNA, which in turn enabled the conception and synthesis of sophisticated and complex 2D and 3D nanostructures. In parallel, polymer science has developed several polymerization approaches to build di- and triblock copolymers bearing hydrophilic, hydrophobic, and amphiphilic properties. By bringing together these two emerging technologies, complementary properties of both materials have been explored; for example, the synthesis of amphiphilic DNA-polymer conjugates has enabled the production of several nanostructures, such as spherical and rod-like micelles. Through both the DNA and polymer parts, stimuli-responsiveness can be instilled. Nanostructures have consequently been developed with responsive structural changes to physical properties, such as pH and temperature, as well as short DNA through competitive complementary binding. These responsive changes have enabled the application of DNA-polymer conjugates in biomedical applications including drug delivery. This review discusses the progress of DNA-polymer conjugates, exploring the synthetic routes and state-of-the-art applications afforded through the combination of nucleic acids and synthetic polymers.

Nanoparticulation of Prodrug into Medicines for Cancer Therapy

This article provides a broad spectrum about the nanoprodrug fabrication advances co-driven by prodrug and nanotechnology development to potentiate cancer treatment. The nanoprodrug inherits the features of both prodrug concept and nanomedicine know-how, attempts to solve underexploited challenge in cancer treatment cooperatively. Prodrugs can release bioactive drugs on-demand at specific sites to reduce systemic toxicity, this is done by using the special properties of the tumor microenvironment, such as pH value, glutathione concentration, and specific overexpressed enzymes; or by using exogenous stimulation, such as light, heat, and ultrasound. The nanotechnology, manipulating the matter within nanoscale, has high relevance to certain biological conditions, and has been widely utilized in cancer therapy. Together, the marriage of prodrug strategy which shield the side effects of parent drug and nanotechnology with pinpoint delivery capability has conceived highly camouflaged Trojan horse to maneuver cancerous threats.

Folate-Guided Protein Degradation by Immunomodulatory Imide Drug-Based Molecular Glues and Proteolysis Targeting Chimeras

Molecular glues and proteolysis targeting chimeras (PROTACs) are promising new therapeutic modalities. However, the lack of specificity for molecular glue- or PROTAC-mediated proteolysis in cancer cells versus normal cells raises potential toxicity concerns that will likely limit their clinical applications. Here, we developed a general strategy to deliver immunomodulatory imide drug (IMiD)-based molecular glues and PROTACs to folate receptor α (FOLR1)-positive cancer cells. Specifically, we designed a folate-caged pomalidomide prodrug, FA-S2-POMA, by incorporating a folate group as a caging and guiding element and validated its degradation effect on its neo-substrates in FOLR1-positive cancer cells in a FOLR1-dependent manner. We also developed a folate-caged pomalidomide-based anaplastic lymphoma kinase (ALK) PROTAC, FA-S2-MS4048, which effectively degraded ALK fusion proteins in cancer cells, again in a FOLR1-dependent manner. This novel approach provides a generalizable platform for the targeted delivery of IMiD-based molecular glues and PROTACs to FOLR1-expressing cancer cells with the potential to ameliorate toxicity.

Spherical Nucleic Acids for Near-Infrared Light-Responsive Self-Delivery of Small-Interfering RNA and Antisense Oligonucleotide

Herein, we developed a photolabile spherical nucleic acid (PSNA) for carrier-free and near-infrared (NIR) photocontrolled self-delivery of small-interfering RNA (siRNA) and antisense oligonucleotide (ASO). PSNA comprised a hydrophilic siRNA shell with a hydrophobic core containing a peptide nucleic acid-based ASO (pASO) and NIR photosensitizer (PS). The incorporation of a singlet oxygen (¹O₂)-cleavable linker between the siRNA and pASO allowed on-demand disassembly of PSNA in tumor cells once ¹O₂ was produced by the inner PS upon NIR light irradiation. The generated ¹O₂ could also concurrently promote lysosomal escape of the released siRNA and pASO to reach cytosolic targets. Both in vitro and in vivo results demonstrated that, under NIR light irradiation, PSNA could suppress hypoxia inducible factor-1α (HIF-1α) and B-cell lymphoma 2 (Bcl-2) for gene therapy (GT), which further combined photodynamic therapy (PDT) favored by the released PS to inhibit tumor cell growth. Given its carrier-free, NIR-sensitive, designable, and biocompatible merits, PSNA represents a promising self-delivery nanoplatform for cancer therapy.

Synthetic Approaches for Copolymers Containing Nucleic Acids and Analogues: Challenges and Opportunities

A deep integration of nucleic acids with other classes of materials have become the basis of many useful technologies. Among these biohybrids, nucleic acid-containing copolymers has seen rapid development in both chemistry and application. This review focuses on the various synthetic approaches to access nucleic acid-polymer biohybrids spanning post-polymerization conjugation, nucleic acids in polymerization, solid-phase synthesis, and nucleoside/nucleobase-functionalized polymers. We highlight the challenges associated with working with nucleic acids with each approach and the ingenuity of the solutions, with the hope of lowering the entry barrier and inpsiring further investigations in this exciting area.

Structure-Based Identification of Potent Lysine-Specific Demethylase 1 Inhibitor Peptides and Temporary Cyclization to Enhance Proteolytic Stability and Cell Growth-Inhibitory Activity

Peptides are attractive drug candidates, but their utility is greatly limited by their inherent susceptibility to proteolytic degradation and their inability to pass through the cell membrane. Here, we employ a strategy of temporary cyclization to develop a cell-active lysine-specific demethylase 1 (LSD1/KDM1A) inhibitor peptide. We first identified a highly potent LSD1-inhibitory linear peptide, with the assistance of X-ray crystal structure data of inhibitor peptide-bound LSD1·CoREST. The peptide was converted to a redox-activatable cyclic peptide incorporating cell-penetrating peptide (CPP), expecting selective activation under intracellular reducing conditions. The cyclic peptide moiety exhibited enhanced stability to protease and was converted to the linear, unmodified LSD1 inhibitor peptide under reducing conditions. The cyclic peptide with CPP inhibited the proliferation of human acute myeloid leukemia cells (HL-60) in the low micromolar concentration range.

Designing Mesoporous Silica Nanoparticles to Overcome Biological Barriers by Incorporating Targeting and Endosomal Escape

The several biological barriers that nanoparticles might encounter when administered to a patient constitute the major bottleneck of nanoparticle-mediated tumor drug delivery, preventing their successful translation into the clinic and reducing their therapeutic profile. In this work, mesoporous silica nanoparticles have been employed as a platform to engineer a versatile nanomedicine able to address such barriers, achieving (a) excessive premature drug release control, (b) accumulation in tumor tissues, (c) selective internalization in tumoral cells, and (d) endosomal escape. The nanoparticles have been decorated with a self-immolative redox-responsive linker to prevent excessive premature release, to which a versatile and polyvalent peptide that is able to recognize tumoral cells and induce the delivery of the nanoparticles to the cytoplasm via endosomal escape has been grafted. The excellent biological performance of the carrier has been demonstrated using 2D and 3D in vitro cell cultures and a tumor-bearing chicken embryo model, demonstrating in all cases high biocompatibility and cytotoxic effect, efficient endosomal escape and tumor penetration, and accumulation in tumors grown on the chorioallantoic membrane of chicken embryos.

Spherical Nucleic Acids for Topical Treatment of Hyperpigmentation

Oligonucleotide-based materials such as spherical nucleic acid (SNA) have been reported to exhibit improved penetration through the epidermis and the dermis of the skin upon topical application. Herein, we report a self-assembled, skin-depigmenting SNA structure, which is based upon a bifunctional oligonucleotide amphiphile containing an antisense oligonucleotide and a tyrosinase inhibitor prodrug. The two components work synergistically to increase oligonucleotide cellular uptake, enhance drug solubility, and promote skin penetration. The particles were shown to reduce melanin content in B16F10 melanoma cells and exhibited a potent antimelanogenic effect in an ultraviolet B-induced hyperpigmentation mouse model.

Carrier-Free Hybrid DNA Nanoparticles for Light-Induced Self-Delivery of Functional Nucleic Acid Enzymes

Herein, we developed hybrid DNAzyme nanoparticles (NPs) to achieve light-induced carrier-free self-delivery of DNAzymes with sufficient cofactor supply and lysosome escape capacity. In this system, aggregation-induced emission (AIE) photosensitizer (PS) (TBD-Br) was grafted onto a phosphorothiolated DNAzyme backbone, which automatically self-assembled to form NPs and the surface phosphorothioate group could easily coordinate with the cofactor Zn²⁺ in the buffer. When the yielded hybrid DNAzyme NPs were located inside tumor cell lysosomes, the ¹O₂ from TBD-Br under light illumination could destroy lysosome structure and promote the Zn²⁺ coordinated DNAzyme NPs escape. Both in vitro and in vivo results demonstrated that the hybrid DNAzyme NPs could downregulate the early growth response factor-1 protein (EGR-1) to inhibit tumor cell growth in addition to induce tumor cell apoptosis by AIE PS (TBD-Br) under light irradiation.

Chemotherapeutic drug-DNA hybrid nanostructures for anti-tumor therapy

Compared to traditional drug delivery systems, DNA nanostructure-based drug delivery systems have several advantages including programmable sequences, precise size and shape, high drug payloads, excellent biocompatibility and biodegradability. To date, a wide range of chemotherapeutic drug-DNA hybrid nanostructures have been developed for anti-tumor therapy. In this review, the constructions of various DNA nanostructures for anticancer drug delivery are firstly summarized. Next, the anticancer drug loading methods for DNA nanostructures are presented. Then, the recent applications of chemotherapeutic drug-DNA hybrid nanostructures for drug delivery are highlighted. In the end, the challenges and opportunities of the chemotherapeutic drug-DNA hybrid nanostructure-based delivery system are discussed. The designs of drug-DNA hybrid systems, including the constructions of nanostructures and the strategies for drug loading, largely influence the efficiency of drug delivery. Recent studies have focused on the development of novel drug-DNA hybrid systems to acquire more precise and efficient therapy for various diseases. A systematic review of the design strategies of chemotherapeutic drug-DNA hybrid nanostructures will benefit the innovation and development of the chemotherapeutic drug-based chemotherapy in clinics.