A supramolecular platform for controlling and optimizing molecular architectures of siRNA targeted delivery vehicles

Copper/calcium co-doped carbon dots for targeted cancer therapy with dual-mode imaging and synergistic induction of cuproptosis and calcium-mediated apoptosis

Squamous cell carcinoma remains a highly aggressive malignancy with persistently high global incidence and mortality rates, posing significant challenges for effective treatment. Traditional chemotherapies lack specificity, leading to damage in normal tissues and severe side effects, highlighting the urgent need for targeted therapeutic strategies. In this study, copper and calcium co-doped carbon dots (Cu/Ca-CDs) were synthesized using a vacuum-confined heating method. These Cu/Ca-CDs demonstrated excellent tumor-targeting ability through specific binding to folate receptors on murine squamous cell carcinoma cell line (SCC7), facilitated by their pterin ring structure. Mechanistic studies revealed that Cu/Ca-CDs induced SCC7 tumor cell death through copper-induced cuproptosis and calcium overload-mediated apoptosis, as confirmed by Western blot, immunofluorescence staining, and Rhod-2 calcium probe analyses. The dual-mode imaging capability of Cu/Ca-CDs, enabled by fluorescence and computed tomography properties, allowed for real-time tracking of their distribution and accumulation within tumors. This imaging-guided approach ensured precise delivery to tumor tissues while minimizing damage to normal tissues. In vivo experiments demonstrated significant tumor volume reduction and increased survival rates in tumor-bearing mice treated with Cu/Ca-CDs, without any observed toxicity to normal tissues or changes in body weight, underscoring the efficacy and biosafety of Cu/Ca-CDs. These findings highlight Cu/Ca-CDs as a promising strategy for precision oncology, offering effective tumor targeting, dual-mode imaging, and synergistic anti-tumor efficacy with reduced side effects.

Recent advances in smart hydrogels derived from polysaccharides and their applications for wound dressing and healing

Owing to their inherent biocompatibility and biodegradability, hydrogels derived from polysaccharides have emerged as promising candidates for wound management. However, the complex nature of wound healing often requires the development of smart hydrogels---intelligent materials capable of responding dynamically to specific physical or chemical stimuli. Over the past decade, an increasing number of stimuli-responsive polysaccharide-based hydrogels have been developed to treat various types of wounds. While a range of hydrogel types and their versatile functions for wound management have been discussed in the literature, there is still a need for a review of the crosslinking strategies used to create smart hydrogels from polysaccharides. This review provides a comprehensive overview of how stimuli-responsive hydrogels can be designed and made using five key polysaccharides: chitosan, hyaluronic acid, alginate, dextran, and cellulose. Various methods, such as chemical crosslinking, dynamic crosslinking, and physical crosslinking, which are used to form networks within these hydrogels, ultimately determine their ability to respond to stimuli, have been explored. This article further looks at different polysaccharide-based hydrogel wound dressings that can respond to factors such as reactive oxygen species, temperature, pH, glucose, light, and ultrasound in the wound environment and discusses how these responses can enhance wound healing. Finally, this review provides insights into how stimuli-responsive polysaccharide-based hydrogels can be developed further as advanced wound dressings in the future.

WRAP-based nanoparticles for siRNA delivery in zebrafish embryos by simple bath immersion

The use of RNA interference (RNAi) is becoming more widespread in several areas of biomedical research. However, the success of RNAi depends on the effective delivery of siRNA in vitro or in vivo. Efforts are under way to identify universally effective delivery systems. Promising candidates include cell-penetrating peptides, such as the WRAP (tryptophan and arginine-rich amphipathic peptide) family, which forms nanoparticles in the presence of short interfering RNA (siRNA). Here, we optimized the WRAP-based nanoparticles for zebrafish embryo transfection by first determining the ideal formulation compatible with the saline solution required for zebrafish embryo care. We found that adding 20% polyethylene glycol (PEG) to the WRAP1 nanoparticles provided the best nanoparticles in terms of size (around 100 nm) and uniformity (PdI ≤0.3), compared with other nanoparticles tested. We then performed a simple soaking procedure in which we exposed dechorionated zebrafish embryos expressing GFP in their vascular cells to siRNA-loaded 20% PEG-WRAP1 nanoparticles. Under these conditions, we showed dose-dependent siRNA internalization and efficient GFP silencing. Although still in its early stages, this proof-of-concept study provides promising prospects for further in vivo research in zebrafish embryos to evaluate the efficacy of gene silencing using PEGylated WRAP1 nanoparticles by skin transfection in a pathophysiological context.

Cyclodextrin-Initiated N-Carboxyanhydride Polymerization for the Design of Stereostructural Dobby Polypeptides with Jellyfish-Type Architecture

Strict criteria of biomedical materials in synthesis efficiency, structure determinacy, and biological safety pose formidable challenges for the synthesis of dobby polypeptides. Herein we reported a cyclodextrin (CD)-initiated, 1,1,3,3-Tetramethylguanidine (TMG)-catalyzed one-step N-carboxyanhydride (NCA) ring-opening polymerization (ROP) strategy to synthesize a series of dobby polypeptides that fulfill the criteria of biomedical materials. By leveraging TMG's catalytic mechanisms in nucleophilicity enhancement for CD hydroxyl groups and active center creation for NCA monomers, this strategy achieves efficient NCA polymerization within 2 hours and high monomer conversion up to 93.5 %. Meticulous characterizations illustrate that CD-centric polypeptides present jellyfish-type stereochemical structures, in which the arm number, length, orientation and initiation sites are precisely determined. Simultaneously, CD-centric polypeptides possess excellent self-assembling capacities to guide nanostructure fabrication, exhibiting broad-spectrum small-molecule drug encapsulation. Additionally, natural CD applied in multipoint initiation of core-first NCA ROP fundamentally improves the biodegradability and biosafety of dobby polypeptides, thus facilitating their biomedical applications.

Supramolecular Polycations with a Linear-Star Architecture Containing Hydrophobic Poly[(R,S)-3-hydroxybutyrate]: Formation of DNA Micelleplexes Coated with Apolipoprotein E3 for Blood-Brain Barrier Penetrating Gene Delivery

A novel blood-brain barrier (BBB)-penetrating supramolecular gene delivery system was developed utilizing a host-guest block-building strategy to systematically screen and optimize various block compositions. Linear poly(ethylene glycol) (PEG) was coupled with hydrophobic poly[(R,S)-β-hydroxybutyrate] (PHB) blocks of varying lengths with an adamantyl (Ad) end, giving the PEG-PHB-Ad guest polymers, which were complexed with the cationic 4-arm star-shaped β-cyclodextrin-poly(2-dimethylaminoethyl methacrylate) (βCD-pDMAEMA) host polymer, resulting in the formation of linear-star pseudoblock PEG-PHB-Ad/βCD-pDMAEMA copolymers. These amphiphilic supramolecular copolymers were thoroughly characterized and assessed for the formation of DNA micelleplex nanoparticles as a gene delivery system. Through a rational selection process, an optimal host-guest configuration was identified, considering critical factors such as cytotoxicity, gene transfection efficiency, serum stability, cellular uptake, and hemolytic activity. The optimized host-guest copolymer was subsequently coated with the targeting protein apolipoprotein E3 (ApoE3), endowing it with BBB-penetrating capabilities, which was validated through an in vitro BBB transwell model.

Receptor-ligand interactions for optimized endocytosis in targeted therapies

Receptor-mediated endocytosis plays a crucial role in the success of numerous therapies and remains central to advancing drug development. This process begins with ligand binding to specific receptors, triggering the internalization and intracellular trafficking of receptor-ligand complexes. These complexes are subsequently directed into distinct routes, either toward lysosomal degradation or recycling to the cell surface, with implications for therapeutic outcomes. This review examines receptor-ligand interactions as key modulators of endocytosis, emphasizing their role in shaping therapeutic design and efficacy. Advances in selecting receptor-ligand pairs and engineering ligands with optimized properties have enabled precise control over internalization, endosomal sorting, and trafficking, providing tailored solutions for diverse therapeutic applications. Leveraging these insights, strategies such as RNA-based therapies, antibody-drug conjugates (ADCs), and targeted protein degradation (TPD) platforms have been refined to selectively avoid or promote lysosomal degradation, thereby enhancing therapeutic efficacy. By bridging fundamental mechanisms of receptor-mediated endocytosis with innovative therapeutic approaches, this review offers a framework for advancing precision medicine.

Theranostics of osteoarthritis: Applications and prospects of precision targeting nanotechnology

Osteoarthritis (OA), a complex degenerative joint disease driven by cartilage degeneration, synovial inflammation, and subchondral bone remodeling, lacks effective disease-modifying therapies. Precision-targeted nanotechnology has emerged as a breakthrough strategy, offering enhanced drug delivery, reduced toxicity, and synergistic diagnostic-therapeutic capabilities. This review summarizes OA pathogenesis, focusing on dysregulated immune networks and self-perpetuating synovial microenvironmental interactions. We discuss advanced nanomedicine approaches, which leverage OA-specific pathological cues for localized treatment. Innovations in cytokine modulation, photothermal therapy, and integrated theranostics (photoacoustic/fluorescence imaging) are highlighted as transformative tools for real-time diagnosis and personalized intervention. Despite progress, challenges such as biocompatibility optimization, clinical translation barriers, OA heterogeneity necessitate further development of multifunctional nanocarriers and rationaldesigns. This work underscores the potential of nanotechnology to advance OA therapeutics, bridging preclinical innovation with clinical applicability in pharmaceutical sciences.

Lactylation-Driven HECTD2 Limits the Response of Hepatocellular Carcinoma to Lenvatinib

Drug resistance remains a major hurdle for the therapeutic efficacy of lenvatinib in hepatocellular carcinoma (HCC). However, the underlying mechanisms remain largely undetermined. Unbiased proteomic screening is performed to identify the potential regulators of lenvatinib resistance in HCC. Patient-derived organoids, patient-derived xenograft mouse models, and DEN/CCl4 induced HCC models are constructed to evaluate the effects of HECTD2 both in vitro and in vivo. HECTD2 is found to be highly expressed in lenvatinib-resistant HCC cell lines, patient tissues, and patient-derived organoids and xenografts. In vitro and in vivo experiments demonstrated that overexpression of HECTD2 limits the response of HCC to lenvatinib treatment. Mechanistically, HECTD2 functions as an E3 ubiquitin ligase of KEAP1, which contributes to the degradation of KEAP1 protein. Subsequently, the KEAP1/NRF2 signaling pathway initiates the antioxidative response of HCC cells. Lactylation of histone 3 on lysine residue 18 facilitates the transcription of HECTD2. Notably, a PLGA-PEG nanoparticle-based drug delivery system is synthesized, effectively targeting HECTD2 in vivo. The NPs achieved tumor-targeting, controlled-release, and biocompatibility, making them a promising therapeutic strategy for mitigating lenvatinib resistance. This study identifies HECTD2 as a nanotherapeutic target for overcoming lenvatinib resistance, providing a theoretical basis and translational application for HCC treatment.

Red Blood Cell Membrane Vesicles for siRNA Delivery: A Biocompatible Carrier With Passive Tumor Targeting and Prolonged Plasma Residency

Background

Despite many advances in gene therapy, the delivery of small interfering RNAs is still challenging. Erythrocytes are the most abundant cells in the human body, and their membrane possesses unique features. From them, erythrocytes membrane vesicles can be generated, employable as nano drug delivery system with prolonged blood residence and high biocompatibility.

Methods

Human erythrocyte ghosts were extruded in the presence of siRNA, and the objects were termed EMVs (erythrocyte membrane vesicles). An ultracentrifugation-based method was applied to select only the densest EMVs, ie, those containing siRNA. We evaluated their activity in vitro in B16F10 cells expressing fluorescent tdTomato and in vivo in B16F10 tumor-bearing mice after a single injection.

Results

The EMVs had a negative zeta potential, a particle size of 170 nm and excellent colloidal stability after one month of storage. With 0.3 nM siRNA, more than 75% gene knockdown was achieved in vitro, and 80% was achieved in vivo, at 2 days PI at 2.5 mg/kg. EMVs mostly accumulate around blood vessels in the lungs, brain and tumor. tdTomato fluorescence steadily decreased in tumor areas with higher EMVs concentration, which indicates efficient gene knockdown. Approximately 2% of the initial dose of EMVs was still present in the plasma after 2 days.

Conclusion

The entire production process of the purified siRNA-EMVs took approximately 4 hours. The erythrocyte marker CD47 offered protection against macrophage recognition in the spleen and in the blood. The excellent biocompatibility and pharmacokinetic properties of these materials make them promising platforms for future improvements, ie, active targeting and codelivery with conventional chemotherapeutics.

Rationally designed β-cyclodextrin-crosslinked polyacrylamide hydrogels for cell spheroid formation and 3D tumor model construction

In vitro tumor models are essential for understanding tumor behavior and evaluating tumor biological properties. Hydrogels that can mimic the tumor extracellular matrix have become popular for creating 3D in vitro tumor models. However, designing biocompatible hydrogels with appropriate chemical and physical properties for constructing tumor models is still a challenge. In this study, we synthesized a series of β-cyclodextrin (β-CD)-crosslinked polyacrylamide hydrogels with different β-CD densities and mechanical properties and evaluated their potential for use in 3D in vitro tumor model construction, including cell capture and spheroid formation. By utilizing a combination of β-CD-methacrylate (CD-MA) and a small amount of N,N'-methylene bisacrylamide (BIS) as hydrogel crosslinkers and optimizing the CD-MA/BIS ratio, the hydrogels performed excellently for tumor cell 3D culture and spheroid formation. Notably, when we co-cultured L929 fibroblasts with HeLa tumor cells on the hydrogel surface, co-cultured spheroids were formed, showing that the hydrogel can mimic the complexity of the tumor extracellular matrix. This comprehensive investigation of the relationship between hydrogel mechanical properties and biocompatibility provides important insights for hydrogel-based in vitro tumor modeling and advances our understanding of the mechanisms underlying tumor growth and progression.

Beyond Lipids: Exploring Advances in Polymeric Gene Delivery in the Lipid Nanoparticles Era

The recent success of gene therapy during the COVID-19 pandemic has underscored the importance of effective and safe delivery systems. Complementing lipid-based delivery systems, polymers present a promising alternative for gene delivery. Significant advances have been made in the recent past, with multiple clinical trials progressing beyond phase I and several companies actively working on polymeric delivery systems which provides assurance that polymeric carriers can soon achieve clinical translation. The massive advantage of structural tunability and vast chemical space of polymers is being actively leveraged to mitigate shortcomings of traditional polycationic polymers and improve the translatability of delivery systems. Tailored polymeric approaches for diverse nucleic acids and for specific subcellular targets are now being designed to improve therapeutic efficacy. This review describes the recent advances in polymer design for improved gene delivery by polyplexes and covalent polymer-nucleic acid conjugates. The review also offers a brief note on novel computational techniques for improved polymer design. The review concludes with an overview of the current state of polymeric gene therapies in the clinic as well as future directions on their translation to the clinic.

DNA nanodevice as a multi-module co-delivery platform for combination cancer immunotherapy

A major challenge in combining cancer immunotherapy is the efficient delivery of multiple types of immunological stimulators to elicit a robust anti-tumor immune response and reprogram the immunosuppressive tumor microenvironment (TME). Here, we developed a DNA nanodevice that was generated by precisely assembling three types of immunological stimulators. The doxorubicin (Dox) component induced immunogenic cell death (ICD) in tumor cells and enhanced phagocytosis of antigen-presenting cells (APCs). Exogenous double-stranded DNA (dsDNA) could act as a molecular adjuvant to activate the stimulator of interferon genes (STING) signaling in APCs by engulfing dying tumor cells. Interleukin (IL)-12 and small hairpin programmed cell death-ligand 1 (shPD-L1) transcription templates were designed to regulate TME. Additionally, for targeted drug delivery, multiple cyclo[Arg-Gly-Asp-(d-Phe)-Cys] (cRGD) peptide units on DNA origami were employed. The incorporation of disulfide bonds allowed the release of multiple modules in response to intracellular glutathione (GSH) in tumors. The nanodevice promoted the infiltration of CD8+ and CD4+ cells into the tumor and generated a highly inflamed TME, thereby enhancing the effectiveness of cancer immunotherapy. Our research results indicate that the nanodevice we constructed can effectively inhibit tumor growth and prevent lung metastasis without obvious systemic toxicity, providing a promising strategy for cancer combination treatment.

A supramolecular colloidal system based on folate-conjugated β-cyclodextrin polymer and indocyanine green for enhanced tumor-targeted cell imaging in 2D culture and 3D tumor spheroids

Indocyanine green (ICG) is an FDA-approved medical diagnostic agent that is widely used as a near-infrared (NIR) fluorescent imaging molecular probe. However, ICG tends to aggregate to form dimers or H-aggregates in water and lacks physical and optical stability, which greatly decreases its absorbance and fluorescence intensity in various applications. Additionally, ICG has no tissue- or tumor-targeting properties, and its structure is not easy to modify, which has further limited its application in cancer diagnosis. In this study, we addressed these challenges by developing a supramolecular colloidal carrier system that targets tumor cells. To this end, we synthesized a water-soluble β-cyclodextrin (β-CD) polymer conjugated with folate (FA), denoted PCD-FA, which is capable of forming inclusion complexes with ICG in water through host-guest interactions between the β-CD moieties and ICG molecules. The inclusion complexes formed by PCD-FA and ICG, called ICG@PCD-FA, dispersed stably in solution as colloidal nanoparticles, greatly improving the physical and optical properties of ICG by preventing ICG dimer formation, where ICG appeared as monomers and even J-aggregates. This resulted in stronger and more stable absorption at a longer wavelength of 900 nm, which may allow for deeper tissue penetration and imaging with reduced interference from biological tissues' autofluorescence. Moreover, ICG@PCD-FA showed a targeting effect on folate receptor-positive (FR+) tumor cells, which specifically highlighted FR+ cells via NIR endoscopic imaging. Notably, ICG@PCD-FA further improved permeation and accumulation in FR+ 3D tumor spheroids. Therefore, this ICG@PCD-FA supramolecular colloidal system may have a great potential for use in tumor NIR imaging and diagnostic applications.

The effect of charge and albumin on cellular uptake of supramolecular polymer nanostructures

Intracellular delivery of functional biomolecules by using supramolecular polymer nanostructures has gained significant interest. Here, various charged supramolecular ureido-pyrimidinone (UPy)-aggregates were designed and formulated via a simple "mix-and-match" method. The cellular internalization of these UPy-aggregates in the presence or absence of serum proteins by phagocytic and non-phagocytic cells, i.e., THP-1 derived macrophages and immortalized human kidney cells (HK-2 cells), was systematically investigated. In the presence of serum proteins the UPy-aggregates were taken up by both types of cells irrespective of the charge properties of the UPy-aggregates, and the UPy-aggregates co-localized with mitochondria of the cells. In the absence of serum proteins only cationic UPy-aggregates could be effectively internalized by THP-1 derived macrophages, and the internalized UPy-aggregates either co-localized with mitochondria or displayed as vesicular structures. While the cationic UPy-aggregates were hardly internalized by HK-2 cells and could only bind to the membrane of HK-2 cells. With adding and increasing the amount of serum albumin in the cell culture medium, the cationic UPy-aggregates were gradually taken up by HK-2 cells without anchoring on the cell membranes. It is proposed that the serum albumin regulates the cellular internalization of UPy-aggregates. These results provide fundamental insights for the fabrication of supramolecular polymer nanostructures for intracellular delivery of therapeutics.

Codelivery of Doxorubicin and p53 Gene by β-Cyclodextrin-Based Supramolecular Nanoparticles Formed via Host-Guest Complexation and Electrostatic Interaction

We developed a supramolecular system for codelivery of doxorubicin (Dox) and p53 gene based on a β-CD-containing star-shaped cationic polymer. First, a star-shaped cationic polymer consisting of a β-CD core and 3 arms of oligoethylenimine (OEI), named CD-OEI, was used to form a supramolecular inclusion complex with hydrophobic Dox. The CD-OEI/Dox complex was subsequently used to condense plasmid DNA via electrostatic interactions to form CD-OEI/Dox/DNA polyplex nanoparticles with positive surface charges that enhanced the cellular uptake of both Dox and DNA. This supramolecular drug and gene codelivery system showed high gene transfection efficiency and effective protein expression in cancer cells. The codelivery of Dox and DNA encoding the p53 gene resulted in reduced cell viability and enhanced antitumor effects at low Dox concentrations. With its enhanced cellular uptake and anticancer efficacy, the system holds promise as a delivery carrier for potential combination cancer therapies.

Rationally designed multifunctional nanoparticles as GSH-responsive anticancer drug delivery systems based on host-guest polymers derived from dextran and β-cyclodextrin

Tumor proliferation and metastasis rely on energy provided by mitochondria. The hexokinase inhibitor lonidamine (LND) could suppress the activities in mitochondria, being a potential antitumor drug. However, limited water-solubility of LND may hinder its biomedical applications. Besides, the cancer-killing effect of LND is compromised by the high level of glutathione (GSH) in cancer cells. Therefore, it is urgent to find a proper method to simultaneously deliver LND and deplete GSH as well as monitor GSH level in cancer cells. Herein, a host polymer β-cyclodextrin-polyethylenimine (β-CD-PEI) and a guest polymer dextran-5-dithio-(2-nitrobenzoic acid) (Dextran-SS-TNB) were synthesized and allowed to form LND-loaded GSH-responsive nanoparticles through host-guest inclusion complexation between β-CD and TNB as host and guest molecular moieties, respectively, which functioned as a system for simultaneous delivery of LND and -SS-TNB species into cancer cells. As a result, the delivery system could deplete GSH and elevate reactive oxygen species (ROS) level in cancer cells, further induce LND-based mitochondrial dysfunction and ROS-based immunogenic cell death (ICD), leading to a synergistic and efficient anticancer effect. In addition, -SS-TNB reacted with GSH to release TNB2-, which could be a probe with visible light absorption at 410 nm for monitoring the GSH level in the cells.

Recent Advances in Mesoporous Silica Nanoparticles Delivering siRNA for Cancer Treatment

Silencing genes using small interfering (si) RNA is a promising strategy for treating cancer. However, the curative effect of siRNA is severely constrained by low serum stability and cell membrane permeability. Therefore, improving the delivery efficiency of siRNA for cancer treatment is a research hotspot. Recently, mesoporous silica nanoparticles (MSNs) have emerged as bright delivery vehicles for nucleic acid drugs. A comprehensive understanding of the design of MSN-based vectors is crucial for the application of siRNA in cancer therapy. We discuss several surface-functionalized MSNs' advancements as effective siRNA delivery vehicles in this paper. The advantages of using MSNs for siRNA loading regarding considerations of different shapes, various options for surface functionalization, and customizable pore sizes are highlighted. We discuss the recent investigations into strategies that efficiently improve cellular uptake, facilitate endosomal escape, and promote cargo dissociation from the MSNs for enhanced intracellular siRNA delivery. Also, particular attention was paid to the exciting progress made by combining RNAi with other therapies to improve cancer therapeutic outcomes.

Enhancing the Gene Transfection of Poly(β-amino ester)/DNA Polyplexes by Modular Manipulation of Amphiphilicity

Poly(β-amino ester)s (PAEs) have been widely developed for gene delivery, and hydrophobic modification can further enhance their gene transfection efficiency. However, systematic manipulation of amphiphilicity of PAEs through copolymerization with hydrophobic monomers is time-consuming and, to some extent, uncontrollable. Here, a modular strategy is developed to manipulate the amphiphilicity of the PAE/DNA polyplexes. A hydrophobic polymer (DD-C12-122) and a hydrophilic polymer (DD-90-122) are synthesized separately and used as a hydrophobic module and a hydrophilic module, respectively. The amphiphilicity of polyplexes could be manipulated by changing the ratio of the hydrophobic module and hydrophilic module. Using the modular strategy, the PAE/DNA polyplexes with the highest gene transfection efficiency and safety profile as well as possible mechanisms are identified. The modular strategy provides a novel way to engineer the hydrophobicity of PAEs to improve their gene transfection and can be easily generalized and potentially extended to other polymeric gene delivery systems.

Controlled spatial characteristics of ligands on nanoparticles: Determinant of cellular functions

Interactions of various ligands and receptors have been extensively investigated because they regulate a series of signal transduction leading to various functional cellular outcomes. The receptors on cell membrane recognize their specific ligands, resulting in specific binding between ligands and receptors. Accumulating evidence reveals that the receptors recognize the difference on the spatial characteristics of ligands as well as the types of ligands. Thus, control on spatial characteristics of multiple ligands presented on therapeutic nanoparticles is believed to impact the cellular functions. Specifically, the localized and multivalent distribution of ligands on nanoparticles can induce receptor oligomerization and receptor clustering, controlling intensity or direction of signal transduction cascades. Here, we will introduce recent studies on the use of material-based nanotechnology to control spatial characteristics of ligands and their effect on cellular functions. These therapeutic nanoparticles with controlled spatial characteristics of ligands may be a promising strategy for maximized therapeutic outcome.

Targeted Anticancer Agent with Original Mode of Action Prepared by Supramolecular Assembly of Antibody Oligonucleotide Conjugates and Cationic Nanoparticles

Despite their clinical success, Antibody-Drug Conjugates (ADCs) are still limited to the delivery of a handful of cytotoxic small-molecule payloads. Adaptation of this successful format to the delivery of alternative types of cytotoxic payloads is of high interest in the search for novel anticancer treatments. Herein, we considered that the inherent toxicity of cationic nanoparticles (cNP), which limits their use as oligonucleotide delivery systems, could be turned into an opportunity to access a new family of toxic payloads. We complexed anti-HER2 antibody-oligonucleotide conjugates (AOC) with cytotoxic cationic polydiacetylenic micelles to obtain Antibody-Toxic-Nanoparticles Conjugates (ATNPs) and studied their physicochemical properties, as well as their bioactivity in both in vitro and in vivo HER2 models. After optimising their AOC/cNP ratio, the small (73 nm) HER2-targeting ATNPs were found to selectively kill antigen-positive SKBR-2 cells over antigen-negative MDA-MB-231 cells in serum-containing medium. Further in vivo anti-cancer activity was demonstrated in an SKBR-3 tumour xenograft model in BALB/c mice in which stable 60% tumour regression could be observed just after two injections of 45 pmol of ATNP. These results open interesting prospects in the use of such cationic nanoparticles as payloads for ADC-like strategies.

Cationic micelles as nanocarriers for enhancing intra-cartilage drug penetration and retention

There is a tremendous unmet medical need for osteoarthritis (OA) treatment around the world, and pharmacological management is the most common option but presents a limited and short efficacy. Insufficient drug delivery to articular cartilage is the key cause. It is widely accepted that the complex structure of articular cartilage and the rapid clearance of joint liquids largely hinder drug penetration and retention in the cartilage. To address these obstacles, we designed and prepared a positively charged micellar system that can effectively deliver a model drug to the deep zone of the cartilage and prolong the drug retention time. In this work, a triblock copolymer composed of cationic poly(N,N-dimethylaminoethyl methacrylate) (PDMAEMA) and poly(ε-caprolactone) (PCL), denoted as PDMAEMA-PCL-PDMAEMA, was synthesized. A triblock copolymer composed of brush poly[poly(ethylene glycol) methacrylate] (pPEGMA) and PCL, denoted as pPEGMA-PCL-pPEGMA, was prepared for comparison. The two types of triblock copolymers were self-assembled in an aqueous environment to form cationic and neutral micelles, respectively. A hydrophobic fluorescent dye as a model drug was loaded into micelle cores, and the dye-loaded micelles were evaluated for intra-cartilage penetration and retention using porcine knee cartilage explants. The PDMAEMA-PCL-PDMAEMA cationic micelles were found to significantly enhance the intra-cartilage penetration and retention capability due to the electrostatic interaction between the micelles and the negatively charged cartilage extracellular matrix. The confocal microscopy study showed that the cationic micelles could penetrate the full-thickness porcine cartilage explants (around 1.5 mm) within 24 hours. Up to 87% of the cationic micelles were taken up by porcine cartilage explants, and 71% of the absorbed micelles were retained in the tissue for at least 4 days. Although the pPEGMA-PCL-pPEGMA neutral micelles were able to penetrate the full-thickness cartilage, this type of micelle showed lower uptake (44%) and retention (44%) rates. This observation implied that the surface charge of micelles could play an important role in efficient intra-cartilage drug delivery. This study verified the feasibility and effectiveness of the PDMAEMA-PCL-PDMAEM cationic micelles in intra-cartilage drug delivery, showing that cationic micelles could be promising carriers for OA treatment.

Red fluorescent AIEgens based multifunctional nonviral gene vectors for the efficient combination of gene therapy and photodynamic therapy in anti-cancer

Precise molecular engineering of AIEgens-based cationic delivery systems for high transfection efficiency (TE) and effective photodynamic therapy (PDT) holds a huge potential for cancer treatment. Herein, three amphiphiles (DT-C_6/8/12-M) consisting of di(triazole-[12]aneN₃) (M) and 1,1-dicyano-2-phenyl-2-(4-diphenylamino)phenyl-ethylene (DT) units have been developed to achieve luminescent tracking, efficient TE, and effective PDT in vitro and in vivo. These compounds exhibited strong aggregated induced emission (AIE) at 630 nm and mega Stokes shifts of up to 160 nm. They were able to bind DNA into nanoparticles with suitable sizes, positive surface potential, and good biocompatibility in the presence of DOPE. Among them, vector DT-C₁₂-M/DOPE with n-dodecyl linker achieved a transfection efficiency as high as 42.3 folds that of Lipo2000 in PC-3 cell lines. DT-C₁₂-M/DOPE exhibited the capability of successful endo/lysosomal escape and rapid nuclear delivery of pDNA, and the gene delivery process was clearly monitored via confocal laser scanning microscopy. Moreover, efficient reactive oxygen species (ROS) generation by DT-C₁₂-M upon light irradiation led to effective PDT in vitro . We further show that combination of p53 gene therapy and PDT dramatically enhanced cancer therapeutic outcome in vivo. This "three birds, one stone" strategy offers a novel and promising approach for real-time tracking of gene delivery and better cancer treatment.

Application of vinyl polymer-based materials as nucleic acids carriers in cancer therapy

Nucleic acid-based therapies have changed the paradigm of cancer treatment, where conventional treatment modalities still have several limitations in terms of efficacy and severe side effects. However, these biomolecules have a short half-life in vivo, requiring multiple administrations, resulting in severe suffering, discomfort, and poor patient compliance. In the early days of (nano)biotechnology, these problems caused concern in the medical community, but recently it has been recognized that these challenges can be overcome by developing innovative formulations. This review focuses on the use of vinyl polymer-based materials for the protection and delivery of nucleic acids in cancer. First, an overview of the properties of nucleic acids and their versatility as drugs is provided. Then, key information on the achievements to date, the most effective delivery methods, and the evaluation of functionalization approaches (stimulatory strategies) are critically discussed to highlight the importance of vinyl polymers in the new cancer treatment approaches. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures.

Nanocarriers for delivery of siRNA as gene silencing mediator

The term nanocarrier refers to sub-micrometric particles of less than 100 nm, designed to transport, distribute, and release nanotechnology-based drug delivery systems. siRNA therapy is a novel strategy that has great utility for a variety of treatments, however naked siRNA delivery has not been an effective strategy, resulting in the necessary use of nanocarriers for delivery. This review aims to highlight the versatility of carriers based on smart drug delivery systems. The nanocarriers based on nanoparticles as siRNA DDS have provided a set of very attractive advantages related to improved physicochemical properties, such as high surface-to-volume ratio, versatility to package siRNA, provide a dual function to both protect extracellular barriers that lead to elimination and overcome intracellular barriers limiting cytosolic delivery, and possible chemical modifications on the nanoparticle surface to improve stability and targeting. Lipid and polymeric nanocarriers have proven to be stable, biocompatible, and effective in vitro, further exploration of the development of new nanocarriers is needed to obtain safe and biocompatible tools for effective therapy.

MicroRNA delivery systems in glioma therapy and perspectives: A systematic review

Gliomas are the deadliest of all primary brain tumors, and they constitute a serious global health problem. MicroRNAs (miRNAs) are gene expression regulators associated with glioma pathogenesis. Thus, miRNAs represent potential therapeutic agents for treating gliomas. However, miRNAs have not been established as part of the regular clinical armamentarium. This systemic review evaluates current molecular and pre-clinical studies with the aim of defining the most appealing supramolecular platform for administering therapeutic miRNA to patients with gliomas. An integrated analysis suggested that cationic lipid nanoparticles, functionalized with octa-arginine peptides, represent a potentially specific, practical, non-invasive intervention for treating gliomas. This supramolecular platform allows loading both hydrophilic (miRNA) and hydrophobic (anti-tumor drugs, like temozolomide) molecules. This systemic review is the first to describe miRNA delivery systems targeted to gliomas that integrate several types of molecules as active ingredients. Further experimental validation is warranted to confirm the practical value of miRNA delivery systems.

Facile Construction of a Two-in-One Injectable Micelleplex-Loaded Thermogel System for the Prolonged Delivery of Plasmid DNA

Nanoparticle-hydrogel systems have recently emerged as a class of interesting hybrid materials with immense potential for several biomedical applications. Remarkably, the incorporation of nanoparticles into a hydrogel may yield synergistic benefits lacking in a singular system. However, most synthetic strategies require laborious steps to achieve the system, severely restricting the process of translational research. Herein, a facile strategy to access a two-in-one system comprising two distinct polyurethane (PU)-based micellar systems is demonstrated and applied as a novel sustained gene delivery platform, where the two PUs are synthesized similarly but with slightly different compositions. One PU forms cationic micelles that complex with plasmid DNA (pDNA), which are loaded into a thermogel formed by another PU micellar system for the prolonged release of pDNA micelleplexes. Specifically, a thermogelling multiblock PU copolymer (denoted as EPH) was synthesized via the step-growth polymerization of poly(ethylene glycol), poly(propylene glycol), and poly(3-hydroxybutyrate). By further introducing a cationic extender, 3-(dimethylamino)-1,2-propanediol, into the reaction feed, a series of cationic PUs (denoted as EPHD) with varying compositions were obtained. The EPHDs formed positively charged micelles in aqueous solutions, efficiently condensed pDNA into nano-sized micelleplexes (<200 nm) at optimized w/w ratios, and mediated transient green fluorescence protein expression in HEK293T cells at 48 h post-transfection. On the other hand, aqueous EPH solution (4 wt %) was injectable at 4 °C and rapidly gelled upon heating to 37 °C to form a stable hydrogel depot. EPHD/pDNA micelleplexes were easily loaded into EPH by mixing the solutions at 4 °C, before heating to 37 °C, leading to the resultant hydrogel system. The in vitro release study revealed that while free pDNA loaded in the thermogel was completely released in 2 weeks, the release of EPHD/pDNA micelleplexes was prolonged to at least 28 days, suggesting substantial micelleplex-hydrogel interactions. Intact, bioactive, and noncytotoxic EPHD/pDNA micelleplexes in the release media were proved by gel retardation, in vitro gene transfection, and CCK-8 cytotoxicity assay results, respectively. Collectively, this work presents a simple approach to achieving and optimizing a novel two-in-one nanoparticle-hydrogel system for the prolonged delivery of pDNA and may be promising for long-term gene delivery applications.

Smart Hydrogel Formed by Alginate-g-Poly(N-isopropylacrylamide) and Chitosan through Polyelectrolyte Complexation and Its Controlled Release Properties

Smart hydrogels that can respond to external stimuli such as temperature and pH have attracted tremendous interest for biological and biomedical applications. In this work, we synthesized two alginate-graft-poly(N-isopropylacrylamide) (Alg-g-PNIPAAm) copolymers and aimed to prepare smart hydrogels through formation of polyelectrolyte complex (PEC) between the negatively charged Alg-g-PNIPAAm copolymers and the positively charged chitosan (Cts) in aqueous solutions. The hydrogels were expected to be able to respond to both temperature and pH changes due to the nature of Alg-g-PNIPAAm and chitosan. The hydrogel formation was determined by a test tube inverting method and confirmed by the rheological measurements. The rheological measurements showed that the PEC hydrogels formed at room temperature could be further enhanced by increasing temperature over the lower critical solution temperature (LCST) of PNIPAAm, because PNIPAAm would change from hydrophilic to hydrophobic upon increasing temperature over its LCST, and the hydrophobic interaction between the PNIPAAm segments may act as additional physical crosslinking. The controlled release properties of the hydrogels were studied by using the organic dye rhodamine B (RB) as a model drug at different pH. The PEC hydrogels could sustain the RB release more efficiently at neutral pH. Both low pH and high pH weakened the PEC hydrogels, and resulted in less sustained release profiles. The release kinetics data were found to fit well to the Krosmyer-Peppas power law model. The analysis of the release kinetic parameters obtained by the modelling indicates that the release of RB from the PEC hydrogels followed mechanisms combining diffusion and dissolution of the hydrogels, but the release was mainly governed by diffusion with less dissolution at pH 7.4 when the PEC hydrogels were stronger and stabler than those at pH 5.0 and 10.0. Therefore, the PEC hydrogels are a kind of smart hydrogels holding great potential for drug delivery applications.

Inhibition of IKKβ/NF-κB signaling facilitates tendinopathy healing by rejuvenating inflamm-aging induced tendon-derived stem/progenitor cell senescence

Degenerative rotator cuff tendinopathy (RCT) is a chronic tendon disease caused by degeneration and inflammation, which often affects the elderly population. Mesenchymal stem cell senescence is generally recognized as an important pathophysiological mechanism in many age-related skeletal diseases. Herein, we collected human tendon-derived stem/progenitor cells (TSPCs) from degenerative supraspinatus tendons and found that TSPC senescence is closely related to RCT. We further identified that nuclear factor κB (NF-κB) pathway activation is involved in age-related inflammation (inflamm-aging) of degenerative RCT. Moreover, whole genome RNA sequencing revealed that in vitro inhibition of the I kappa B kinase β (IKKβ)/NF-κB signaling pathway could reverse the aged TSPC phenotype with decreased TSPC senescence and increased tenogenic potential. To achieve effective in vivo inhibition of IKKβ/NF-κB signaling, we fabricated IKKβ small interfering RNA (siRNA)-loaded gold nanoclusters (AuNC-siRNA) for efficient and convenient intra-articular delivery of IKKβ siRNA. We found that AuNC-siRNA prevented inflamm-aging-induced TSPC senescence and dysfunction in a degenerative RCT aged rat model. Together, these data show that inflamm-aging causes degenerative RCT through inducing TSPC senescence, which can be reversed by blocking the IKKβ/NF-κB pathway in vivo. Thus, our study provides a promising therapeutic strategy for degenerative RCT via intra-articular delivery of IKKβ siRNA using AuNCs.

Mining for novel cyclomaltodextrin glucanotransferases unravels the carbohydrate metabolism pathway via cyclodextrins in Thermoanaerobacterales

Carbohydrate metabolism via cyclodextrins (CM-CD) is an uncommon starch-converting pathway that thoroughly depends on extracellular cyclomaltodextrin glucanotransferases (CGTases) to transform the surrounding starch substrate to α-(1,4)-linked oligosaccharides and cyclodextrins (CDs). The CM-CD pathway has emerged as a convenient microbial adaptation to thrive under extreme temperatures, as CDs are functional amphipathic toroids with higher heat-resistant values than linear dextrins. Nevertheless, although the CM-CD pathway has been described in a few mesophilic bacteria and archaea, it remains obscure in extremely thermophilic prokaryotes (Topt ≥ 70 °C). Here, a new monophyletic group of CGTases with an exceptional three-domain ABC architecture was detected by (meta)genome mining of extremely thermophilic Thermoanaerobacterales living in a wide variety of hot starch-poor environments on Earth. Functional studies of a representative member, CldA, showed a maximum activity in a thermoacidophilic range (pH 4.0 and 80 °C) with remarkable product diversification that yielded a mixture of α:β:γ-CDs (34:62:4) from soluble starch, as well as G3-G7 linear dextrins and fermentable sugars as the primary products. Together, comparative genomics and predictive functional analysis, combined with data of the functionally characterized key proteins of the gene clusters encoding CGTases, revealed the CM-CD pathway in Thermoanaerobacterales and showed that it is involved in the synthesis, transportation, degradation, and metabolic assimilation of CDs.

A hydrogel with supramolecular surface functionalization for cancer cell capture and multicellular spheroid growth and release

A hydrogel scaffold with a non-fouling but specific cancer cell-adhesive surface was fabricated through surface modification using β-cyclodextrin-based host-guest chemistry. Interestingly, the hydrogel surface not only selectively captured specific cancer cells, but also grew the cells into multicellular spheroids. The spheroids could be released without damaging the cell viability through replacing the host moieties on the scaffold, and the released spheroids showed no changes in size or morphology.

Non-viral vectors for RNA delivery

RNA-based therapy is a promising and potential strategy for disease treatment by introducing exogenous nucleic acids such as messenger RNA (mRNA), small interfering RNA (siRNA), microRNA (miRNA) or antisense oligonucleotides (ASO) to modulate gene expression in specific cells. It is exciting that mRNA encoding the spike protein of COVID-19 (coronavirus disease 2019) delivered by lipid nanoparticles (LNPs) exhibits the efficient protection of lungs infection against the virus. In this review, we introduce the biological barriers to RNA delivery in vivo and discuss recent advances in non-viral delivery systems, such as lipid-based nanoparticles, polymeric nanoparticles, N-acetylgalactosamine (GalNAc)-siRNA conjugate, and biomimetic nanovectors, which can protect RNAs against degradation by ribonucleases, accumulate in specific tissue, facilitate cell internalization, and allow for the controlled release of the encapsulated therapeutics.

Lignin-Based Nonviral Gene Carriers Functionalized by Poly[2-(Dimethylamino)ethyl Methacrylate]: Effect of Grafting Degree and Cationic Chain Length on Transfection Efficiency

Lignin is a natural renewable biomass resource with great potential for applications, while its development into high value-added molecules or materials is rare. The development of biomass lignin as potential nonviral gene delivery carriers was initiated by our group through the "grafting-from" approach. Firstly, the lignin was modified into macroinitiator using 2-bromoisobutyryl bromide. Then cationic polymer chains of poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) were grown from the lignin backbone using atom transfer radical polymerization (ATRP) to yield lignin-PDMAEMA graft copolymers (LPs) with branched structure. To gain a deep understanding of the relationship between the nonviral gene transfection efficiency of such copolymers and their structural and compositional factors, herein eight lignin-based macroinitiators with different modification degrees (MDs, from 3.0 to 100%) were synthesized. Initiated by them, a series of 20 LPs were synthesized with varied structural factors such as grafting degree (GD, which is equal to MD, determining the cationic chain number per lignin macromolecule), cationic chain length (represented by number of repeating DMAEMA units per grafted arm or degree of polymerization, DP) as well as the content of N element (N%) which is due to the grafted PDMAEMA chains and proportional to molecular weight of the LPs. The in vitro gene transfection capability of these graft copolymers was evaluated by luciferase assay in HeLa, COS7 and MDA-MB-231cell lines. Generally, the copolymers LP-12 (N% = 7.28, MD = 36.7%, DP = 13.6) and LP-14 (N% = 6.05, MD = 44.4%, DP = 5.5) showed good gene transfection capabilities in the cell lines tested. Overall, the performance of LP-12 was the best among all the LPs in the three cell lines at the N/P ratios from 10 to 30, which was usually several times higher than PEI standard. However, in MDA-MB-231 at N/P ratio of 30, LP-14 showed the best gene transfection performance among all the LPs. Its gene transfection efficiency was ca. 11 times higher than PEI standard at this N/P ratio. This work demonstrated that, although the content of N element (N%) which is due to the grafted PDMAEMA chains primarily determines the gene transfection efficiency of the LPs, it is not the only factor in explaining the performance of such copolymers with the branched structure. Structural factors of these copolymers such as grafting degree and cationic chain length could have a profound effect on the copolymer performance on gene transfection efficiency. Through carefully adjusting these factors, the gene transfection efficiency of the LPs could be modulated and optimized for different cell lines, which could make this new type of biomass-based biomaterial an attractive choice for various gene delivery applications.

Cardiomyocyte-targeted anti-inflammatory nanotherapeutics against myocardial ischemia reperfusion (IR) injury

Myocardial ischemia reperfusion (IR) injury is closely related to the overwhelming inflammation in the myocardium. Herein, cardiomyocyte-targeted nanotherapeutics were developed for the reactive oxygen species (ROS)-ultrasensitive co-delivery of dexamethasone (Dex) and RAGE small interfering RNA (siRAGE) to attenuate myocardial inflammation. PPTP, a ROS-degradable polycation based on PGE₂-modified, PEGylated, ditellurium-crosslinked polyethylenimine (PEI) was developed to surface-decorate the Dex-encapsulated mesoporous silica nanoparticles (MSNs), which simultaneously condensed siRAGE and gated the MSNs to prevent the Dex pre-leakage. Upon intravenous injection to IR-injured rats, the nanotherapeutics could be efficiently transported into the inflamed cardiomyocytes via PGE₂-assisted recognition of over-expressed E-series of prostaglandin (EP) receptors on the cell membranes. Intracellularly, the over-produced ROS degraded PPTP into small segments, promoting the release of siRAGE and Dex to mediate effective RAGE silencing (72%) and cooperative antiinflammatory effect. As a consequence, the nanotherapeutics notably suppressed the myocardial fibrosis and apoptosis, ultimately recovering the systolic function. Therefore, the current nanotherapeutics represent an effective example for the co-delivery and on-demand release of nucleic acid and chemodrug payloads, and might find promising utilities toward the synergistic management of myocardial inflammation.

ELECTRONIC SUPPLEMENTARY MATERIAL

Supplementary material (experimental methods, RNA and primer sequences, ¹H NMR spectra, FTIR spectrum, TEM images, zeta potential, drug loading content, RNA and drug release, cytotoxicity, etc.) is available in the online version of this article at 10.1007/s12274-022-4553-6.

Supramolecular Surface Functionalization of Iron Oxide Nanoparticles with α-Cyclodextrin-Based Cationic Star Polymer for Magnetically-Enhanced Gene Delivery

Supramolecular polymers formed through host-guest complexation have inspired many interesting developments of functional materials for biological and biomedical applications. Here, we report a novel design of a non-viral gene delivery system composed of a cationic star polymer forming supramolecular complexes with the surface oleyl groups of superparamagnetic iron oxide nanoparticles (SPIONs), for magnetically enhanced delivery of DNA into mammalian cells. The cationic star polymer was synthesized by grafting multiple oligoethylenimine (OEI) chains onto an α-cyclodextrin (α-CD) core. The SPIONs were synthesized from iron(III) acetylacetonate and stabilized by hydrophobic oleic acid and oleylamine in hexane, which were characterized in terms of their size, structure, morphology, and magnetic properties. The synthesized magnetic particles were found to be superparamagnetic, making them a suitable ferrofluid for biological applications. In order to change the hydrophobic surface of the SPIONs to a hydrophilic surface with functionalities for plasmid DNA (pDNA) binding and gene delivery, a non-traditional but simple supramolecular surface modification process was used. The α-CD-OEI cationic star polymer was dissolved in water and then mixed with the SPIONs stabilized in hexane. The SPIONs were "pulled" into the water phase through the formation of supramolecular host-guest inclusion complexes between the α-CD unit and the oleyl surface of the SPIONs, while the surface of the SPIONs was changed to OEI cationic polymers. The α-CD-OEI-SPION complex could effectively bind and condense pDNA to form α-CD-OEI-SPION/pDNA polyplex nanoparticles at the size of ca. 200 nm suitable for delivery of genes into cells through endocytosis. The cytotoxicity of the α-CD-OEI-SPION complex was also found to be lower than high-molecular-weight polyethylenimine, which was widely studied previously as a standard non-viral gene vector. When gene transfection was carried out in the presence of an external magnetic field, the α-CD-OEI-SPION/pDNA polyplex nanoparticles greatly increased the gene transfection efficiency by nearly tenfold. Therefore, the study has demonstrated a facile two-in-one method to make the SPIONs water-soluble as well as functionalized for enhanced magnetofection.

A siRNA-Assisted Assembly Strategy to Simultaneously Suppress "Self" and Upregulate "Eat-Me" Signals for Nanoenabled Chemo-Immunotherapy

Effectively activating macrophages that can engulf cancer cells is a promising immunotherapeutic strategy but remains a major challenge due to the expression of "self" signals (e.g., CD47 molecules) by tumor cells to prevent phagocytosis. Herein, we explored a siRNA-assisted assembly strategy for the simultaneous delivery of siRNA and mitoxantrone hydrochloride (MTO·2HCl) via PLGA-based nanoparticles. The siRNA suppressed a "self" signal by silencing the CD47 gene, while the MTO induced surface exposure of calreticulin (CRT) to provide an "eat-me" signal. The siRNA-assisted assembly strategy synergistically increased the phagocytosis of tumor cells by macrophages, promoted effective antigen presentation, and initiated T cell-mediated immune responses in two aggressive tumor animal models of melanoma and colon cancer, eventually achieving significantly improved antitumor activity. This study provides a straightforward codelivery strategy to simultaneously suppress "self" and upregulate "eat-me" signals to potentiate macrophage-mediated immunotherapy.

Tumor acid microenvironment-activated self-targeting & splitting gold nanoassembly for tumor chemo-radiotherapy

Low accumulation and penetration of nanomedicines in tumor severely reduce therapeutic efficacy. Herein, a pH-responsive gold nanoassembly is designed to overcome these problems. Polyethylene glycol linked raltitrexed (RTX, target ligand and chemotherapy drug) and two tertiary amine molecules (1-(2-aminoethyl) pyrrolidine and N,N-dibutylethylenediamine) are modified on the surface of the 6-nm gold nanoparticles by lipoic acid to form gold nanoassembly defined as Au-NNP(RTX). The Au-NNP (RTX) nanoassembly could remain at about 160 nm at the blood circulation (pH 7.4), while split into 6-nm gold nanoparticles due to tertiary amine protonation at tumor extracellular pH (pH 6.8). This pH-responsive disassembly behavior endows Au-NNP(RTX) better tumor tissue permeability through the better diffusion brought by the size reduction. Meanwhile, after disassembly, more RTXs on the surface of gold nanoparticles are exposed from the shielded state of assembly along with 2.25-fold augment of cellular uptake capability. Most importantly, the results show that Au-NNP(RTX) possesses of high tumor accumulation and effective tumor penetration, thereby enhancing the tumor chemo-radiotherapy efficiency.

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A pH-responsive self-targeting & splitting gold nanoassembly is fabricated.

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The nanoassembly holds better tumor tissue permeability by the size reduction.

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The nanoassembly enhances targeting capability by ligand shielding and exposure.

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Clever design endows the system synergistic effect of chemo-radiotherapy.

Degradable cationic polyesters via ring-opening copolymerization of valerolactones as nanocarriers for the gene delivery

The development of cationic polymers as non-viral gene vectors has been hurdled by their high toxicity, thus degradable and biocompatible polymers are urgently demanded. Herein, five polyesters (B3a-B3e) were synthesized based on the ring-opening copolymerization between α-allyl-δ-valerolactone and δ-valerolactone derivatives decorated with alkyl or alkoxyl chains of different lengths, followed by the modification with 1,5,9-triazacyclododecyl ([12]aneN₃) through thiol-ene click reactions. The five polyesters effectively condensed DNA into nanoparticles. Of them, B3a with a shorter alkyl chain and B3d with more positive charged units showed stronger DNA condensing performance and can completely retard the migration of DNA at N/P = 1.6 in the presence of DOPE. B3b/DOPE with a longer alkyl chain exhibited the highest transfection efficiency in HeLa cells with 1.8 times of 25 kDa PEI, while B3d/DOPE with more positive charged units exhibited highest transfection efficiency in A549 cells with 2.3 times of 25 kDa PEI. B3b/DOPE and B3d/DOPE successfully delivered pEGFP into zebrafish, which was superior to 25 kDa PEI (1.5 folds and 1.1 folds, respectively). The cytotoxicity measurements proved that the biocompatibility of these polyesters was better than 25 kDa PEI, due to their degradable property in acid environment. The results indicated that these cationic polyesters can be developed as potential non-viral gene vectors for DNA delivery.

Nonviral DNA Delivery System with Supramolecular PEGylation Formed by Host-Guest Pseudo-Block Copolymers

A cationic supramolecular system based on host-guest pseudoblock copolymers was developed for nonviral DNA delivery. In this system, the macromolecular host was a cationic star-shaped polymer composed of a β-cyclodextrin (β-CD) core and multiple poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) chains grafted on the core, while the macromolecular guest was a linear adamantyl-ended poly(ethylene glycol) (mPEG-Ad). Pseudoblock copolymers were self-assembled from the polymeric host-guest pairs (typically, 1:1 molar ratio) in aqueous media through the inclusion of an adamantyl group at the end of guest polymer into the β-CD cavity of host polymers. Through such an approach, the resultant supramolecular system was integrated with not only a superior DNA condensing ability due to the host polymer but also an outstanding polyplex-stabilizing ability as well as biocompatibility due to the guest polymer. The cationic star-shaped host polymers alone were capable of condensing plasmid DNA efficiently into nanoparticles (70-100 nm) with positive surface charge. They showed obviously lower cytotoxicity than PEI 25K (commercial branched polyethylenimine with a molecular weight around 25 kDa) in cell lines of L929, MB231, and Hela under high dose. In serum-free or serum-containing culture conditions, these host polymers exhibited either higher or lower in vitro DNA transfection efficiency as compared with PEI 25K in the three cell lines under study, which was dependent on the N/P ratios and PDMAEMA arm length. Upon incorporation of the PEG block through host-guest complexation with mPEG-Ad (i.e., supramolecular PEGylation), the resulting host-guest supramolecular systems exhibited even lower cytotoxicity than the host polymers alone. The polyplexes between plasmid DNA (pDNA) and the host-guest systems showed significantly improved stability in BSA-PBS buffer solution (pH 7.4) and enhanced in vitro DNA transfection efficiency in the cases of higher N/P ratios or longer PDMAEMA arms in all tested cell lines under both serum-free and serum-containing culture conditions, as compared with the corresponding polyplexes without supramolecular PEGylation. Further, through forming pseudoblock copolymer, the DNA transfection ability of the supramolecular system can be easily modulated and optimized either by changing the ratio between the guest and host or by using different hosts with varied PDMAEMA arm lengths.

Structural Insights into the Host-Guest Complexation between β-Cyclodextrin and Bio-Conjugatable Adamantane Derivatives

Understanding the host–guest chemistry of α-/β-/γ- cyclodextrins (CDs) and a wide range of organic species are fundamentally attractive, and are finding broad contemporary applications toward developing efficient drug delivery systems. With the widely used β-CD as the host, we herein demonstrate that its inclusion behaviors toward an array of six simple and bio-conjugatable adamantane derivatives, namely, 1-adamantanol (adm-1-OH), 2-adamantanol (adm-2-OH), adamantan-1-amine (adm-1-NH₂), 1-adamantanecarboxylic acid (adm-1-COOH), 1,3-adamantanedicarboxylic acid (adm-1,3-diCOOH), and 2-[3-(carboxymethyl)-1-adamantyl]acetic acid (adm-1,3-diCH₂COOH), offer inclusion adducts with diverse adamantane-to-CD ratios and spatial guest locations. In all six cases, β-CD crystallizes as a pair supported by face-to-face hydrogen bonding between hydroxyl groups on C2 and C3 and their adjacent equivalents, giving rise to a truncated-cone-shaped cavity to accommodate one, two, or three adamantane derivatives. These inclusion complexes can be terminated as (adm-1-OH)₂⊂CD₂ (1, 2:2), (adm-2-OH)₃⊂CD₂ (2, 3:2), (adm-1-NH₂)₃⊂CD₂ (3, 3:2), (adm-1-COOH)₂⊂CD₂ (4, 2:2), (adm-1,3-diCOOH)⊂CD₂ (5, 1:2), and (adm-1,3-diCH₂COOH)⊂CD₂ (6, 1:2). This work may shed light on the design of nanomedicine with hierarchical structures, mediated by delicate cyclodextrin-based hosts and adamantane-appended drugs as the guests.

Photoregulation of Gene Expression with Ligand-Modified Caged siRNAs through Host/Guest Interaction

Small interfering RNA (siRNA) can effectively silence target genes through Argonate 2 (Ago2)-induced RNA interference (RNAi). It is very important to control siRNA activity in both spatial and temporal modes. Among different masking strategies, photocaging can be used to regulate gene expression through light irradiation with spatiotemporal and dose-dependent resolution. Many different caging strategies and caging groups have been reported for light-activated siRNA gene silencing. Herein, we describe a novel caging strategy that increases the blocking effect of RISC complex formation/process through host/guest (including ligand/receptor) interactions, thereby enhancing the inhibition of caged siRNA activity until light activation. This strategy can be used as a general approach to design caged siRNAs for the photomodulation of gene silencing of exogenous and endogenous genes.