Target-specific gene silencing of layer-by-layer assembled gold-cysteamine/siRNA/PEI/HA nanocomplex

Cysteamine functionalized gold nanoparticles exhibit high efficiency delivery of genetic materials in embryonic stem cells majorly via clathrin mediated endocytosis

Efficient and safe gene delivery is vital for genetic manipulation of stem cells for regenerative medicine. Gold nanoparticles have been used for various biomedical applications in the past, and are currently being researched as transfection agents. In this study, we report a simple one-pot synthesis of positively charged gold nanoparticles functionalized with cysteamine. The nanoparticles exhibit no cytotoxicity and can bind to both plasmid DNA (pDNA) as well as small interference RNA (siRNA). We observed that a five fold lower concentration of pDNA was sufficient for achieving comparable overexpression as that of a commercial transfection agent. We also observed that about 70 % transient silencing of the target gene was achieved with only 25 nM siRNA delivered by our nano-vehicle. To better understand the fate of the nanoparticle, we attempted to identify its uptake mechanism. The results indicate that while all the mechanisms contribute to the uptake, the clathrin-dependent pathway plays a major role. This is the first study on understanding the mechanism of uptake of CA-AuNPs conjugated to pDNA by embryonic stem cells. This is also the first study, where a successful transfection using gold based nanoparticles has been achieved in ESCs at a concentration as low as 0.5 µg/ml for pDNA and 25ƞM siRNA.

Comparison of Cell-Penetrating and Fusogenic TAT-HA2 Peptide Performance in Peptideplex, Multicomponent, and Conjugate siRNA Delivery Systems

In this study, the performance of the cell-penetrating and fusogenic peptide, TAT-HA2, which consists of a cell-permeable HIV trans-activator of transcription (TAT) protein transduction domain and a pH-responsive influenza A virus hemagglutinin protein (HA2) domain, was comparatively evaluated for the first time in peptideplex, multicomponent, and conjugate siRNA delivery systems. TAT-HA2 in all three systems protected siRNA from degradation, except in the conjugate system with a low Peptide/siRNA ratio. The synergistic effect of different peptide domains enhanced the transfection efficiency of multicomponent and conjugate systems compared to that of peptideplexes, which was attributed to the surface configuration of TAT-HA2 peptides depending on the nature of attachment. Particularly, the multicomponent system showed better cellular uptake and endosomal escape than the peptideplexes, resulting in enhanced siRNA delivery in the cytoplasm. In addition, the presence of cleavable disulfide bonds in multicomponent and conjugate systems promoted the effective siRNA delivery in the cytoplasm, resulting in improved gene silencing activity. The multicomponent system reduced the level of luciferase expression in SKOV3 cells to 45% (±4). In contrast, the conjugate system and the commercially available siRNA transfection agent, Lipofectamine RNAiMax, caused luciferase suppression down to 55% (±2) at a siRNA dose of 100 nM. For the same dose, the peptideplex system could only reduce the luciferase expression to 65% (±5). None of the developed systems showed significant toxicity at any dose. Overall, the TAT-HA2 peptide is promising as a siRNA delivery vector; however, its performance depends on the nature of attachment and, as a result, its surface configuration on the developed delivery system.

Gold-siRNA supraclusters enhance the anti-tumor immune response of stereotactic ablative radiotherapy at primary and metastatic tumors

Strategies to enhance the anti-tumor immune response of stereotactic ablative radiotherapy (SABR) at primary tumors and abscopal sites are under intensive investigation. Here we report a metabolizable binary supracluster (BSCgal) that combines gold nanoclusters as radiosensitizing adjuvants with small interfering RNA (siRNA) targeting the immunosuppressive mediator galectin-1 (Gal-1). BSCgal comprises reversibly crosslinked cationic gold nanoclusters and siRNA complexes in a polymer matrix that biodegrades over weeks, facilitating clearance (90.3% in vivo clearance at 4 weeks) to reduce toxicity. The particle size well above the renal filtration threshold facilitates passive delivery to tumors. Using mouse models of head and neck cancer, we show that BSCgal augments the radiodynamic and immunotherapeutic effects of SABR at the primary and metastatic tumors by promoting tumor-inhibitory leukocytes, upregulating cytotoxic granzyme B and reducing immunosuppressive cell populations. It outperforms SABR plus Gal-1 antagonists, chemoradiation drug cisplatin or PD-1 inhibitor. This work presents a translatable strategy to converge focal radiosensitization with targeted immune checkpoint silencing for personalized radioimmunotherapy.

Nano-Micron Combined Hydrogel Microspheres: Novel Answer for Minimal Invasive Biomedical Applications

Hydrogels, key in biomedical research for their hydrophilicity and versatility, have evolved with hydrogel microspheres (HMs) of micron-scale dimensions, enhancing their role in minimally invasive therapeutic delivery, tissue repair, and regeneration. The recent emergence of nanomaterials has ushered in a revolutionary transformation in the biomedical field, which demonstrates tremendous potential in targeted therapies, biological imaging, and disease diagnostics. Consequently, the integration of advanced nanotechnology promises to trigger a new revolution in the realm of hydrogels. HMs loaded with nanomaterials combine the advantages of both hydrogels and nanomaterials, which enables multifaceted functionalities such as efficient drug delivery, sustained release, targeted therapy, biological lubrication, biochemical detection, medical imaging, biosensing monitoring, and micro-robotics. Here, this review comprehensively expounds upon commonly used nanomaterials and their classifications. Then, it provides comprehensive insights into the raw materials and preparation methods of HMs. Besides, the common strategies employed to achieve nano-micron combinations are summarized, and the latest applications of these advanced nano-micron combined HMs in the biomedical field are elucidated. Finally, valuable insights into the future design and development of nano-micron combined HMs are provided.

Nanotechnology strategies to address challenges in topical and cellular delivery of siRNAs in skin disease therapy

Gene therapy is one of the most advanced therapies in current medicine. In particular, interference RNA-based therapy by small interfering RNA (siRNA) has gained attention in recent years as it is a highly versatile, selective and specific therapy. In dermatological conditions, topical delivery of siRNA offers numerous therapeutic advantages, mainly by inhibiting the expression of target transcripts directly in the skin. However, crossing the stratum corneum and overcoming intracellular barriers is an inherent challenge. Substantial efforts by scientists have moved towards the use of multimodal and multifunctional nanoparticles to overcome these barriers and achieve greater bioavailability in their site of action, the cytoplasm. In this review the most innovative strategies based on nanoparticle and physical methods are presented, as well as the design principles and the main factors that contribute to the performance of these systems. This review also highlights the synergistic contributions of medicine, nanotechnology, and molecular biology to advancing translational research into siRNA-based therapeutics for skin diseases.

Chemically Modified Platforms for Better RNA Therapeutics

RNA-based therapies have catalyzed a revolutionary transformation in the biomedical landscape, offering unprecedented potential in disease prevention and treatment. However, despite their remarkable achievements, these therapies encounter substantial challenges including low stability, susceptibility to degradation by nucleases, and a prominent negative charge, thereby hindering further development. Chemically modified platforms have emerged as a strategic innovation, focusing on precise alterations either on the RNA moieties or their associated delivery vectors. This comprehensive review delves into these platforms, underscoring their significance in augmenting the performance and translational prospects of RNA-based therapeutics. It encompasses an in-depth analysis of various chemically modified delivery platforms that have been instrumental in propelling RNA therapeutics toward clinical utility. Moreover, the review scrutinizes the rationale behind diverse chemical modification techniques aiming at optimizing the therapeutic efficacy of RNA molecules, thereby facilitating robust disease management. Recent empirical studies corroborating the efficacy enhancement of RNA therapeutics through chemical modifications are highlighted. Conclusively, we offer profound insights into the transformative impact of chemical modifications on RNA drugs and delineates prospective trajectories for their future development and clinical integration.

In vivo senescence imaging nanoprobe targets the associated reactive oxygen species

Cellular senescence, a cell-cycle arrest state upon stress or damage, can adversely impact aging and cancers. We have designed a novel near infrared fluorogenic nanoprobe, named D3, which can only be turned on by highly elevated levels of reactive oxygen species (ROS), critical players for the induction and maintenance of senescence, for real-time senescence sensing and imaging. In contrast to glowing senescent cells, non-senescent cells whose ROS levels are too low to activate the D3 signal remain optically silent. Upon systemic injection into senescent tumor-bearing mice, the D3 nanoprobe quickly accumulates in tumors, and its fluorescence signal is turned on specifically by senescence-associated ROS in the senescent tumors. The fluorescence signal at senescent tumors was 3-fold higher than that of non-senescent tumors. This groundbreaking design introduces a novel activation mechanism and a powerful imaging nanoprobe to identify and assess cellular senescence in living organisms.

DNAi-peptide nanohybrid smart particles target BCL-2 oncogene and induce apoptosis in breast cancer cells

Genomic DNA sequences provide unique target sites, with high druggability value, for treatment of genetically-linked diseases like cancer. B-cell lymphoma protein-2 (BCL-2) prevents Bcl-2-associated X protein (BAX) and Bcl-2 antagonist killer 1 (BAK) oligomerization, which would otherwise lead to the release of several apoptogenic molecules from the mitochondrion. It is also known that BCL-2 binds to and inactivates BAX and other pro-apoptotic proteins, thereby inhibiting apoptosis. BCL-2 protein family, through its role in regulation of apoptotic pathways, is possibly related to chemo-resistance in almost half of all cancer types including breast cancer. Here for the first time, we have developed a nanohybrid using a peptide-based carrier and a Deoxyribonucleic acid inhibitor (DNAi) against BCL-2 oncogene to induce apoptosis in breast cancer cells. The genetically designed nanocarrier was functionalized with an internalizing RGD (iRGD) targeting motif and successfully produced by recombinant DNA technology. Gel retardation assay demonstrated that the peptide-based carrier binds single-stranded DNAi upon simple mixing. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) analyses further revealed the formation of nanohybrid particles with a size of 30 nm and a slightly positive charge. This hemocompatible nanohybrid efficiently delivered its contents into cancer cells using iRGD targeting moiety. Gene expression analysis demonstrated that the nanohybrids, which contained DNAi against BCL-2 proficiently suppressed the expression of this oncogene in a sequence specific manner. In addition, the nanohybrid, triggered release of cytochrome c (cyt c) and caspase3/7 activation with high efficiency. Although the DNAi and free nanocarrier were separately unable to affect the cell viability, the nanohybrid of 20 nM of DNAi showed outstanding antineoplastic potential, which was adjusted by the ratio of the MiRGD nanocarrier to DNAi. It should be noted that, the designed nanohybrid showed a suitable specificity profile and did not affect the viability of normal cells. The results suggest that this nanohybrid may be useful for robust breast cancer treatment through targeting the BCL-2 oncogene without any side effects.

Delivery of siRNA using hyaluronic acid‐guided nanoparticles for downregulation of CXCR4

In this study, effective transport of small interfering RNAs (siRNAs) via hyaluronic acid (HA) receptor was carried out with biodegradable HA and low-molecular weight polyethyleneimine (PEI)-based transport systems. Gold nanoparticles (AuNPs) capable of giving photothermal response, and their conjugates with PEI and HA, were also added to the structure. Thus, a combination of gene silencing, photothermal therapy and chemotherapy, has been accomplished. The synthesized transport systems ranged in size, between 25 and 690 nm. When the particles were applied at a concentration of 100 μg mL^-1 (except AuPEI NPs) in vitro, cell viability was above 50%. Applying radiation after the conjugate/siRNA complex (especially those containing AuNP) treatment, increased the cytotoxic effect (decrease in cell viability of 37%, 54%, 13%, and 15% for AuNP, AuPEI NP, AuPEI-HA, and AuPEI-HA-DOX, respectively) on the MDA-MB-231 cell line. CXCR4 gene silencing via the synthesized complexes, especially AuPEI-HA-DOX/siRNA was more efficient in MDA-MB-231 cells (25-fold decrease in gene expression) than in CAPAN-1 cells. All these results demonstrated that the synthesized PEI-HA and AuPEI-HA-DOX conjugates can be used as siRNA carriers that are particularly effective, especially in the treatment of breast cancer.

Hierarchy of hybrid materials. Part-II: The place of organics-on-inorganics in it, their composition and applications

Hybrid materials or hybrids incorporating organic and inorganic constituents are emerging as a very potent and promising class of materials due to the diverse but complementary nature of their properties. This complementarity leads to a perfect synergy of properties of the desired materials and products as well as to an extensive range of their application areas. Recently, we have overviewed and classified hybrid materials describing inorganics-in-organics in Part-I (Saveleva, et al., Front. Chem., 2019, 7, 179). Here, we extend that work in Part-II describing organics-on-inorganics, i.e., inorganic materials modified by organic moieties, their structure and functionalities. Inorganic constituents comprise of colloids/nanoparticles and flat surfaces/matrices comprise of metallic (noble metal, metal oxide, metal-organic framework, magnetic nanoparticles, alloy) and non-metallic (minerals, clays, carbons, and ceramics) materials; while organic additives can include molecules (polymers, fluorescence dyes, surfactants), biomolecules (proteins, carbohydtrates, antibodies and nucleic acids) and even higher-level organisms such as cells, bacteria, and microorganisms. Similarly to what was described in Part-I, we look at similar and dissimilar properties of organic-inorganic materials summarizing those bringing complementarity and composition. A broad range of applications of these hybrid materials is also presented whose development is spurred by engaging different scientific research communities.

Polyethyleneimine-Based Drug Delivery Systems for Cancer Theranostics

With the development of nanotechnology, various types of polymer-based drug delivery systems have been designed for biomedical applications. Polymer-based drug delivery systems with desirable biocompatibility can be efficiently delivered to tumor sites with passive or targeted effects and combined with other therapeutic and imaging agents for cancer theranostics. As an effective vehicle for drug and gene delivery, polyethyleneimine (PEI) has been extensively studied due to its rich surface amines and excellent water solubility. In this work, we summarize the surface modifications of PEI to enhance biocompatibility and functionalization. Additionally, the synthesis of PEI-based nanoparticles is discussed. We further review the applications of PEI-based drug delivery systems in cancer treatment, cancer imaging, and cancer theranostics. Finally, we thoroughly consider the outlook and challenges relating to PEI-based drug delivery systems.

Development of targeted gene delivery system based on liposome and PAMAM dendrimer functionalized with hyaluronic acid and TAT peptide: in vitro and in vivo studies

The development of gene delivery systems is essential to improve their transfection efficiency and cytotoxicity. Combination of lipid and polymeric nanoparticles with the characteristics of both systems have been considered as a next-generation gene delivery platform. In the current study, we designed a novel and efficient targeted gene delivery system based on liposome and PAMAM dendrimer in cancer cells. Two polymeric formulations containing polyamidoamine-TAT (PAMAM-TAT) and PAMAM-TAT-Hyaluronic acid (HA) and two lipopolymeric carriers including PAMAM-TAT-Liposome and PAMAM-TAT-HA-Liposome were complexed with the Enhanced Green Fluorescent Protein (EGFP) plasmid and then evaluated in terms of physicochemical characteristics. The cytotoxicity and transfection efficiency of these synthetized carriers were accomplished against murine colon carcinoma cell line (C26). The biodistribution of polyplexes and lipoployplexes was also evaluated in the C26 tumor bearing mice. The results showed no significant toxicity for all designed nanoparticles (NPs) in C/P4. The highest gene expression was observed using lipopolyplex PAMAM-TAT-HA-Liposome in C/P4 (ratio polymer/DNA; w/w). Biodistribution study demonstrated more aggregation of targeted lipopolyplex in tumor cells than other nanoparticles (NPs). It could be concluded that the developed targeted lipopolymeric complex could serve as promising nanotherapeutic system for gene therapy. This article is protected by copyright. All rights reserved.

Chitosan-Hyaluronan Nanoparticles for Vinblastine Sulfate Delivery: Characterization and Internalization Studies on K-562 Cells

In the present study, we developed chitosan/hyaluronan nanoparticles (CS/HY NPs) for tumor targeting with vinblastine sulfate (VBL), that can be directed to the CD44 transmembrane receptor, over-expressed in cancer cells. NPs were prepared by coating with HY-preformed chitosan/tripolyphosphate (CS/TPP) NPs, or by polyelectrolyte complexation of CS with HY. NPs with a mean hydrodynamic radius (R_H) of 110 nm, 12% polydispersity index and negative zeta potential values were obtained by a direct complexation process. Transmission Electron Microscopy (TEM) images showed spherical NPs with a non-homogeneous matrix, probably due to a random localization of CS and HY interacting chains. The intermolecular interactions occurring between CS and HY upon NPs formation were experimentally evidenced by micro-Raman (µ-Raman) spectroscopy, through the analysis of the spectral changes of characteristic vibrational bands of HY during NP formation, in order to reveal the involvement of specific chemical groups in the process. Optimized NP formulation efficiently encapsulated VBL, producing a drug sustained release for 20 h. In vitro studies demonstrated a fast internalization of labeled CS/HY NPs (within 6 h) on K-562 human myeloid leukemia cells. Pre-saturation of CD44 by free HY produced a slowing-down of NP uptake over 24 h, demonstrating the need of CD44 for the internalization of HY-based NPs.

pH-Responsive hyaluronic acid-cloaked polycation/gold nanohybrids for tumor-targeted synergistic photothermal/gene therapy

The combination of photothermal therapy (PTT) and gene therapy (GT) has attracted intense interest in cancer treatment. However, the lack of long circulation and active tumor targeting reduces the therapeutic efficacy of complementary PTT/GT. In this work, hyaluronic acid (HA)-cloaked gold nanorods-PGED (prepared by ring-opening of polyglycidyl methacrylate (PGMA) with ethylenediamine (ED))/pDNA (AP/pDNA-HA) complexes were prepared to achieve long circulation and tumor targeting for photoacoustic imaging (PAI)-guided synergistic PTT/GT. Gold nanorods endow the complexes with photothermal effect and PAI function. Benefiting from the HA cloak, the AP/pDNA-HA complexes exhibit excellent stability, biocompatibility, long circulation behavior and active targeting. In addition, the pH-responsive characteristic of the Schiff base bonds helps the AP/pDNA-HA complexes to effectively escape from the endosome/lysosome. The antioncogene p53 was employed to investigate the gene transfection efficiency of the delivery system both in vitro and in vivo. The superiority of synergistic PTT/GT is established in a mouse 4T1 breast tumor model. The current study provides a facile strategy for constructing multifunctional gene delivery systems with long circulation and tumor targeting features, which can achieve effective imaging-guided synergistic tumor treatment.

Strategies for improving the safety and RNAi efficacy of noncovalent peptide/siRNA nanocomplexes

In the past decades, the striking development of cationic polypeptides and cell-penetrating peptides (CPPs) tailored for small interfering RNA (siRNA) delivery has been fuelled by the conception of nuclear acid therapy and precision medicine. Owing to their amino acid compositions, inherent secondary structures as well as diverse geometrical shapes, peptides or peptide-containing polymers exhibit good biodegradability, high flexibility, and bio-functional diversity as nonviral siRNA vectors. Also, a variety of noncovalent nanocomplexes could be built via self-assembling and electrostatic interactions between cationic peptides and siRNAs. Although the peptide/siRNA nanocomplex-based RNAi therapies, STP705 and MIR-19, are under clinical trials, a guideline addressing the current bottlenecks of peptide/siRNA nanocomplex delivery is in high demand for future research and development. In this review, we present strategies for improving the safety and RNAi efficacy of noncovalent peptide/siRNA nanocomplexes in the treatment of genetic disorders. Through thorough analysis of those RNAi formulations using different delivery strategies, we seek to shed light on the rationale of peptide design and modification in constructing robust siRNA delivery systems, including targeted and co-delivery systems. Based on this, we provide a timely and comprehensive understanding of how to engineer biocompatible and efficient peptide-based siRNA vectors.

Lipid based nanocarriers for effective drug delivery and treatment of diabetes associated liver fibrosis

Non-alcoholic fatty liver disease (NAFLD) is a cluster of several liver diseases like hepatic steatosis, non-alcoholic steatohepatitis (NASH), non-alcoholic fatty liver (NAFL), liver fibrosis, and cirrhosis which may eventually progress to liver carcinoma. One of the primary key factors associated with the development and pathogenesis of NAFLD is diabetes mellitus. The present review emphasizes on diabetes-associated development of liver fibrosis and its treatment using different lipid nanoparticles such as stable nucleic acid lipid nanoparticles, liposomes, solid lipid nanoparticles, nanostructured lipid carriers, self-nanoemulsifying drug delivery systems, and conjugates including phospholipid, fatty acid and steroid-based. We have comprehensively described the various pathological and molecular events linking effects of elevated free fatty acid levels, insulin resistance, and diabetes with the pathogenesis of liver fibrosis. Various passive and active targeting strategies explored for targeting hepatic stellate cells, a key target in liver fibrosis, have also been discussed in detail in this review.

Delivery of antisense oligonucleotides using multi-layer coated gold nanoparticles to methicillin-resistant S. aureus for combinatorial treatment

The spread of multidrug-resistant (MDR) bacterial infections has become a serious global threat. We introduce multi-layer coated gold nanoparticles (MLGNPs) delivering antisense oligonucleotides (ASOs) targeting the resistance gene of methicillin-resistant Staphylococcus aureus (MRSA), as a selective antimicrobial by restoring susceptibility. MLGNPs were prepared by multi-step surface immobilization of gold nanoparticles (GNPs) with polyethylenimine (PEI) and loaded with ASO targeting the mecA gene. The MLGNPs were shown to be efficiently internalized into various types of Gram-positive bacteria, including MRSA, Staphylococcus epidermidis, and Bacillus subtilis, which was superior to single-layer coated GNPs and free PEI polymer. The delivery of MLGNPs into MRSA resulted in up to 74% silencing of the mecA gene with high selectivity, in a dose-dependent manner. The treatment of MLGNPs to MRSA in the presence of oxacillin, a beta-lactam antibiotic, showed major suppression (~71%) of bacterial growth, due to the recovery of antibacterial sensitivity. Furthermore, the treatment of MLGNPs in a complex system showed preferential uptake into bacteria over mammalian cells, demonstrating the suitable characteristics of MLGNPs for selective delivery into bacteria. The current approach can be potentially applied for targeting various types of MDR bacterial infections by specific silencing of a resistance gene, as a combinatorial therapeutic used with conventional antibiotics.

Magnetism and NIR dual-response polypyrrole-coated Fe3O4 nanoparticles for bacteria removal and inactivation

Microbial contamination of water represents a great threat to the public health that has attracted worldwide attention. In this work, polypyrrole magnetic nanoparticles (Fe₃O₄@PPy NPs) with sterilization properties were fabricated. More specifically, the Fe₃O₄@PPy NPs obtained via aqueous dispersion polymerization and an in situ chemical oxidative polymerization exhibited a cationic surface and high photothermal conversion efficiency. More than 50% of bacteria adsorption can be achieved at a dosage of 100 μg/mL Fe₃O₄@PPy NPs under magnetic field, and high photothermal sterilization efficacy (~100%) can be obtained upon NIR exposure at the same dosage for 10 min. Noteworthy, the Fe₃O₄@PPy NPs can be recycled by magnetism and reused without affecting their photothermal sterilization capability. This study clearly provides experimental evidence of the great potential of Fe₃O₄@PPy NPs as stable and reusable nanocomposite materials for bacteria adsorption and photothermal sterilization performance. The application of Fe₃O₄@PPy NPs can realize enviromental-friendly bacterial contaminated water treatment as well as provide stratgies for synergistical antibacterial materials design.

β-Cyclodextrin-grafted hyaluronic acid as a supramolecular polysaccharide carrier for cell-targeted drug delivery

β-Cyclodextrin (β-CD) was grafted onto hyaluronic acid (HA) in a single step to generate a supramolecular biopolymer (HA-β-CD) that was explored for targeted drug delivery applications. Along with its excellent biocompatibility, the prepared HA-β-CD exhibits not only exceptionally high loading capacity for the model drugs doxorubicin and Rhodamine B through the formation of inclusion complexes with the β-CD component, but also the capability of targeted drug delivery to cancerous cells with a high level of expression of CD44 receptors, attributable to its HA component. The polymer can release the drug under slightly acidic conditions. With all its attributes, HA-β-CD may be a promising cancer-cell-targeting drug carrier.

Delivery Systems for Nucleic Acids and Proteins: Barriers, Cell Capture Pathways and Nanocarriers

Gene therapy has been used as a potential approach to address the diagnosis and treatment of genetic diseases and inherited disorders. In this line, non-viral systems have been exploited as promising alternatives for delivering therapeutic transgenes and proteins. In this review, we explored how biological barriers are effectively overcome by non-viral systems, usually nanoparticles, to reach an efficient delivery of cargoes. Furthermore, this review contributes to the understanding of several mechanisms of cellular internalization taken by nanoparticles. Because a critical factor for nanoparticles to do this relies on the ability to escape endosomes, researchers have dedicated much effort to address this issue using different nanocarriers. Here, we present an overview of the diversity of nanovehicles explored to reach an efficient and effective delivery of both nucleic acids and proteins. Finally, we introduced recent advances in the development of successful strategies to deliver cargoes.

Construction of Hyaluronic Acid-Covered Hierarchically Porous MIL-nanoMOF for Loading and Controlled Release of Doxorubicin

The porous nano-sized metal-organic framework (nanoMOF) and its proper surface modification could greatly promote the drug loading capability and introduce biocompatibility, biodegradability, and targeting functions into nano-drug delivery systems. Herein, the HACD@ADA-PA/MIL-101_NH₂ (Fe)-P nanoparticle was successfully fabricated through supramolecular and coordination interactions from three building blocks, including hierarchically porous MIL-101_NH₂ (Fe)-P nanoMOF, phosphite-modified adamantane (ADA-PA), and β-cyclodextrin (β-CD)-modified hyaluronic acid (HACD). The obtained HACD@ADA-PA/MIL-101_NH₂ (Fe)-P nanoparticle was nano-sized and highly stable in physiological fluids. The porous structure of HACD@ADA-PA/MIL-101_NH₂ (Fe)-P nanoparticle could effectively load the commercial chemotherapeutic drug doxorubicin (DOX) with an encapsulation rate of 41.20 % and a loading rate of 48.84 %. The obtained drug-loaded HACD@ADA-PA/MIL-101_NH₂ (Fe)-P@DOX nanoparticle was pH-sensitive and relatively stable at neutral condition (pH 7.2) but could release DOX in a controlled way in subacid solution at pH 5.7. The simulated in vitro DOX release experiment signified that the HACD@ADA-PA/MIL-101_NH₂ (Fe)-P@DOX nanoparticle could realize the controlled release of DOX in tumor issues.

Harnessing pH-Sensitive Polycation Vehicles for the Efficient siRNA Delivery

pH-sensitive hydrophobic segments have been certificated to facilitate siRNA delivery efficiency of amphiphilic polycation vehicles. However, optimal design concepts for these vehicles remain unclear. Herein, by studying the library of amphiphilic polycations mPEG-PAMA50-P(DEAx-r-D5Ay) (EAE5x/y), we concluded a multifactor matching concept (pKa values, "proton buffering capacities" (BCs), and critical micelle concentrations (CMCs)) for polycation vehicles to improve siRNA delivery efficiency in vitro and in vivo. We identified that the stronger BCs in a pH 5.5-7.4 subset induced by EAE548/29 (pKa = 6.79) and EAE539/37 (pKa = 6.20) are effective for siRNA delivery in vitro. Further, the stronger BCs occurred in a narrow subset of pH 5.5-6.5 and the lower CMC attributed to higher siRNA delivery capacity of EAE539/37 in vivo than EAE548/29 after intravenous administration and subcutaneous injection. More importantly, 87.2% gene knockdown efficacy was achieved by EAE539/37 via subcutaneous injection, which might be useful for an mRNA vaccine adjuvant. Furthermore, EAE539/37 also successfully delivered siRRM2 to tumor via intravenous administration and received highly efficient antitumor activity. Taken together, the suitable pKa values, strong BCs occurred in pH 5.5-6.5, and low CMCs were probably the potential solution for designing efficient polycationic vehicles for siRNA delivery.

Assembly strategy of liposome and polymer systems for siRNA delivery

In recent years, gene therapy has made tremendous progress in the development of disease treatment. Among them, siRNA offers specificity of gene silencing, ease of synthesis, and short development period, and has been intensively studied worldwide. However, siRNA as the hydrophilic polyanion is easily degraded in vivo and poorly taken up into cells and so, the benefits of its powerful gene silencing ability will not be realized until better carriers are developed that are capable of protecting siRNA and delivering it intact to the cytoplasm of the target cells. Cationic liposomes (CL) and cationic polymers (CP) are the main non-viral siRNA vectors, there have been a lot of reports on the use of these two carriers to deliver siRNA. Whereas, as far as we know, there have been few review articles that provide an in-depth summary of the siRNA loading principle and internal structures of the siRNA delivery system. We summarize the formation principle and assembly structure of the cationic liposome-siRNA and polymer-siRNA complexes, and point out their advantages and characteristics and also show how to perfect their assembly and improve their clinical application in the future. It supports some useful suggestions for siRNA therapy, specifically, safe and efficient delivery.

Parallel Multiparameter Study of PEI-Functionalized Gold Nanoparticle Synthesis for Biomedical Applications: Part 2. Elucidating the Role of Surface Chemistry and Polymer Structure in Performance

Elucidating the polyethyleneimine (PEI) chemistry to predictively and reproducibly synthesize gold nanoparticle (AuNP)-PEI conjugates with desired properties has been elusive despite evaluation in numerous studies and reported enhanced properties. The lack of reproducible methods to control the core size and stability has led to contradictory results for performance and safety; thus, advancement of the conjugate platform for commercial use has likely been hindered. Recently, we reported a robust, reproducible method for synthesizing PEI-functionalized AuNPs (Au-PEIs), providing an opportunity to investigate structure-function relationships and to further investigate synthesis parameters affecting performance, where only materials stable in biological media are candidates for use. The properties of Au-PEIs prepared by the optimized reduction of HAuCl₄ using four different structural variants of PEI changed significantly with the PEI molar mass and backbone form (branched or linear). In the present study using our previously reported synthesis procedure, comprehensive analysis of properties such as size distribution, surface plasmon resonance (SPR), morphological state, surface functionality, and the shelf life has been systematically evaluated to elucidate the role of surface chemistry and reactive groups involved in conjugation, as a function of conjugate size and morphology. Being important for commercial adoption, the chemistry was related to the observed colloidal stability of the product in relevant media, including exposure to physiological variables such as salt, pH, proteins, and thermal changes. Overall, this work advances progress toward smart design of engineered nanoscale drug delivery systems and devices by providing unreported details of contributions affecting formation, stability, and fate.

Small interfering RNA for cancer treatment: overcoming hurdles in delivery

In many ways, cancer cells are different from healthy cells. A lot of tactical nano-based drug delivery systems are based on the difference between cancer and healthy cells. Currently, nanotechnology-based delivery systems are the most promising tool to deliver DNA-based products to cancer cells. This review aims to highlight the latest development in the lipids and polymeric nanocarrier for siRNA delivery to the cancer cells. It also provides the necessary information about siRNA development and its mechanism of action. Overall, this review gives us a clear picture of lipid and polymer-based drug delivery systems, which in the future could form the base to translate the basic siRNA biology into siRNA-based cancer therapies.

Gene Therapy and Photothermal Therapy of Layer-by-Layer Assembled AuNCs /PEI/miRNA/ HA Nanocomplexes

BACKGROUND

MicroRNA (miRNA) therapy, which was widely considered to treat a series of cancer, has been confronted with numerous obstacles to being delivered into target cells because of its easy biodegradation and instability.

METHODS

In this research, we successfully constructed 11-mercaptoundecanoic acid modified gold nanocages (AuNCs)/polyethyleneimine (PEI)/miRNA/hyaluronic acid (HA) complexes (abbreviated as AuNCs/PEI/miRNA/HA) using a layer-by-layer method for target-specific intracellular delivery of miRNA by HA receptor mediated endocytosis.

RESULTS

The results of UV spectra, hydrodynamic diameter and zeta potential analyses confirmed the formation of AuNCs/PEI/ miRNA/HA complex with its average particle size of ca. 153 nm and surface charge of ca. -9.43 mV. Next, we evaluated the antitumor effect of the nanocomplex mediated by the combination of gene therapy and photothermal therapy (PTT) against hepatocellular carcinoma (HCC) in vitro.

CONCLUSION

Our experimental results indicated that the AuNCs/PEI/miRNA/HA complex effectively delivered miRNA to the target cells and its antitumor effect was significantly enhanced by the combination of gene therapy and photothermal therapy. In addition, anti-miR-181b could promote Bel-7402 cell arrest in S phase and improve TIMP-3 mRNA expression. All these results suggested that AuNCs/PEI/miRNA/HA gene delivery system with combination of gene therapy and photothermal therapy might be exploited for HCC treatment.

Supramolecular Hyaluronic Assembly with Aggregation-Induced Emission Mediated in Two Stages for Targeting Cell Imaging

Supramolecular aggregation-induced emission (AIE) has become a research hotspot in cell imaging. Herein, supramolecular assembly with AIE effect was constructed in two stages, where adamantane modified tetraphenylethene self-assembly emitted weak fluorescence, and then after adding β-cyclodextrin modified hyaluronic acid, the formed nanoparticles enhanced AIE fluorescence for targeted cancer cell imaging.

Surface-decorated nanoparticles clicked into nanoparticle clusters for oligonucleotide encapsulation

Gold nanoparticles (AuNPs) are the predominant and representative metal nano-carriers used for the tumor-targeted delivery of therapeutics because they possess advantages such as biocompatibility, high drug loading efficiency, and enhanced accumulation at tumor sites via the size-dependent enhanced permeability and retention (EPR) effect. In this study, we designed an AuNP functionalized with block polymers comprising polyethylenimine and azide group-functionalized poly(ethyl glycol) for the electrostatic incorporation of cytosine–guanine oligonucleotide (CpG ODN) on the surface. The ODN-incorporated AuNPs were cross-linked to gold nanoparticle clusters (AuNCs) via click chemistry using a matrix metalloproteinase (MMP)-2 cleavable peptide linker modified with alkyne groups at both ends. In the presence of Cu(i), azide groups and alkyne groups spontaneously cyclize to form a triazole ring with high fidelity and efficiency, and therefore allow single AuNPs to stack to larger AuNCs for increased EPR effect-mediated tumor targeting. ¹H-NMR and Fourier transform infrared spectroscopy revealed the successful synthesis of an azide–PEG-grafted branched polyethylenimine, and the size and morphology of AuNPs fabricated by the synthesized polymer were confirmed to be 4.02 ± 0.45 nm by field emission-transmission electron microscopy. Raman spectroscopy characterization demonstrated the introduction of azide groups on the surface of the synthesized AuNPs. Zeta-potential and gel-retardation analysis of CpG-loaded AuNPs indicated complete CpG sequestration by AuNPs when the CpG : AuNP weight ratio was higher than 1 : 2.5. The clustering process of the CpG-loaded AuNPs was monitored and was demonstrated to be dependent on the alkyne linker-to-AuNP ratio. Thus, the clicked AuNC can be tailored as a gene carrier where a high accumulation of therapeutics is required.

AuNPs with bPEI and azide modification are loaded with CpG and self-assembled to AuNCs by click chemistry using an alkyne-terminated MMP-2 cleavable peptide as a linker. The clusters are dissembled by MMP-2 to release CpG in a stimuli-responsive manner.

Rekindling RNAi Therapy: Materials Design Requirements for In Vivo siRNA Delivery

With the recent FDA approval of the first siRNA-derived therapeutic, RNA interference (RNAi)-mediated gene therapy is undergoing a transition from research to the clinical space. The primary obstacle to realization of RNAi therapy has been the delivery of oligonucleotide payloads. Therefore, the main aims is to identify and describe key design features needed for nanoscale vehicles to achieve effective delivery of siRNA-mediated gene silencing agents in vivo. The problem is broken into three elements: 1) protection of siRNA from degradation and clearance; 2) selective homing to target cell types; and 3) cytoplasmic release of the siRNA payload by escaping or bypassing endocytic uptake. The in vitro and in vivo gene silencing efficiency values that have been reported in publications over the past decade are quantitatively summarized by material type (lipid, polymer, metal, mesoporous silica, and porous silicon), and the overall trends in research publication and in clinical translation are discussed to reflect on the direction of the RNAi therapeutics field.

Multilayered Activatable Nanoprobe for Ultra-Bright Tumor Imaging

The development of tumor targeted probes with strong signal and high contrast is always challenging in cancer imaging. Here, a unique multilayered activatable nanoprobe (MAN) is prepared to fulfill this long-standing goal. MAN adopts a versatile layer-by-layer fabrication technique that sequentially assembles multifunctional polyelectrolytes onto nanoparticles via charge-charge interaction. Unlike the common one-probe-one-fluorochrome construct, MAN offers a dramatic fluorescence enhancement by transporting a large quantity of quenched fluorochromes for maximal signal and contrast. Excellent signal amplification and retention with negligible cytotoxicity is observed in cell study. Upon systemic injection into mice, MAN quickly accumulates in tumor and its fluorescent signal is turned on by proteases overexpressed in tumors, resulting in >700% tumor-to-normal-tissue contrast. This multilayered fabrication provides a simple and powerful universal platform to design sensitive tumor imaging probes.

l-Histidine Crystals as Efficient Vehicles to Deliver Hydrophobic Molecules

l-Histidine (l-His) molecules can form highly ordered fluorescent crystals with tunable size and geometry. The polymorph A crystal of l-His contains hydrophobic domains within the structure's interior. Here, we demonstrate that these hydrophobic domains can serve as vehicles for highly efficient entrapment and transport of hydrophobic small molecules. This strategy shows the ability of l-His crystals to mask the hydrophobicity of various small molecules, helping to address issues related to their poor solubility and low bioavailability. Furthermore, we demonstrate that we can modify the surface of these crystals to define their function, suggesting the significance of l-His crystals in designing site-specific and bioresponsive platforms. As a demonstration, we use l-His crystals with loaded doxorubicin, featuring hyaluronic acid covalently bonded on the crystal surface, controlling its release in response to hyaluronidase. This strategy for entrapment of hydrophobic small molecules suggests the potential of l-His crystals for targeted drug-delivery applications.

Triggered RNAi Therapy Using Metal Inorganic Nanovectors

The administration of small interfering RNA (siRNA) is a very interesting therapeutic option to treat genetic diseases such as Alzheimer's or some types of cancer, but its effective delivery still remains a challenge. Herein, Au nanorod (GNR)-based platforms functionalized with polyelectrolyte layers were developed and analyzed as potential siRNA nanocarriers. The polymeric layers were successfully assembled on the particle surfaces by means of the layer-by-layer assembly technique through the alternating deposition of oppositely charged poly(styrene)sulfonate, PSS, poly(lysine), PLL, and siRNA biopolymers, with a final hyaluronic acid layer in order to provide the nanoconstructs with a potential targeting ability as well as colloidal stability in physiological medium. Once the hybrid nanocarriers were obtained, the cargo release, their colloidal stability in physiological-relevant media, cytotoxicity, cellular internalization and uptake, and knockdown activity were studied. The present hybrid particles release the genetic material inside cells by means of a protease-assisted and/or a light-triggered release mechanism in order to control the delivery of the oligonucleotides on demand. In addition, the hybrid nanovectors were observed to be nontoxic to cells and could efficiently deliver the genetic material in the cell cytoplasms. The GNR-based nanocarriers proposed here can provide a suitable environment to load and protect a sufficient amount of the genetic material to allow an efficient and sustained knockdown gene expression for long (up to 93% for 72 h), thanks to the slow degradation of PLL, without the observation of adverse side toxic effects. It was also found that the silencing activity was enhanced with the number of siRNA layers assembled in the nanoplatforms.

Multilayer nanoscale functionalization to treat disorders and enhance regeneration of bone tissue

The coatings application onto medical devices has experienced a continuous growth in the last few years. Medical device coating market is expected to grow at a CAGR of 5.16% to reach USD 10 million by 2023 due to the increasing geriatric population and the growing demand for continuous innovation. Layer-by-Layer (LbL) assembly represents a versatile method to modify the surface properties, in order to control cell interaction and thus enhance biological functions. Furthermore, LbL is environmentally friendly, able to coat all types of surfaces with the creation of homogenous film and to include and control the release of biomolecules/drugs. This feature review provides a critical overview on recent progresses in functionalizing materials by LbL assembly for bone regeneration and disorder treatment. An overview of emerging and visionary opportunities on LbL technologies and further combination with other existing methods used in biomedical field, is also discussed to evidence the new challenges and potential developments in bone regenerative medicine.

Multifunctional hyaluronate - nanoparticle hybrid systems for diagnostic, therapeutic and theranostic applications

Diagnostic and therapeutic nanoparticles have been actively investigated for the last few decades as new platforms for biomedical applications. Despite their great versatility and potency, nanoparticles have generally required further modification with biocompatible materials such as biopolymers and synthetic polymers for in vivo administration to improve their biological functions, stability, and biocompatibility. Among a variety of natural and synthetic biomaterials, hyaluronate (HA) has been considered a promising biomolecule with which to construct nanohybrid systems, as it can enable long-term and efficient delivery of nanoparticles to target sites as well as physiological stabilization of nanoparticles by forming hydrophilic shells. In this review, we first describe various kinds of HA derivatives and their interactions with nanoparticles, and discuss how to design and develop optimal HA-nanoparticle hybrid systems for biomedical applications. Furthermore, we show several exemplary applications of HA-nanoparticle hybrid systems and provide our perspectives to their futuristic translational applications.

Hyaluronic Acid Nanoparticle Composite Films Confer Favorable Time-Dependent Biofunctions for Vascular Wound Healing

Vascular stent implantation is the primary treatment for coronary artery disease. Surface modification of coronary stents is a topic of interest to prevent thrombosis and restenosis and to promote endothelization. However, bioactive coatings on implants have not yet been fully developed for the time-ordered biological requirements of vascular stents. The first month after vascular stent implantation, the pathological changes in the injured vascular tissue are complex and time-ordered. Therefore, vascular stents possess time-dependent biofunctions with early phase anticoagulant and anti-inflammatory properties. In the later stage, inhibitory effects on smooth muscle cell proliferation and the promotion of endothelial cell adhesion might meet the requirements of vascular repair. We fabricated three types of hyaluronic acid nanoparticles (HA-NPs) by subjecting HA and poly(ether imide) to ethyl(dimethylaminopropyl) carbodiimide/N-hydroxysuccinimide coupling reaction. The HA-NPs prepared by HA with a molecular weight of 100 kDa showed the best stability in a hyaluronidase environment. HA-NP composite films (HA-NCFs) were then fabricated by coimmobilizing selected HA-NPs (100 kDa) and HA molecules (100 kDa) through amide reaction on PDA/HD coated 316 L stainless steel surfaces. The detachment behavior of HA-NPs (100 kDa) in PBS for 20 days indicated that the HA-NPs (100 kDa) gradually detached from the surface. In vitro tests (anticoagulant and anti-inflammatory tests, endothelial cells, and smooth muscle cells seeding, and bacterial adhesion test) indicated that the newly fabricated HA-NCFs have inhibitory effects on the adhesion of fibrinogen, platelets, macrophages, bacteria, SMCs, and ECs. As the HA-NPs detached from the surface, the HA-NCFs showed excellent gradual comprehensive biocompatibility, which promoted adhesion and proliferation of ECs while still exerting inhibitory effects on the platelets, macrophages, and SMCs. Finally, in vivo SS wire implantation test (aortic implantation in healthy Sprague-Dawley rats) showed that HA-NCFs possessed anti-inflammatory properties, inhibited the proliferation of smooth muscle cells, and promoted re-endothelialization. In particular, HA-NCFs with time-dependent biofunctions showed better antirestenosis effects than those of surfaces modified with molecular HA, which exhibited constant biocompatibility. This study provides an important basis for the construction of HA-NP composite films with favorable time-dependent biofunctions for the time-ordered biological requirements of vascular stent.

Recent Progress in Macromolecule-Anchored Hybrid Gold Nanomaterials for Biomedical Applications

Gold nanoparticles (AuNPs), with elegant thermal, optical, or chemical properties due to quantum size effects, may serve as unique species for therapeutic or diagnostic applications. It is worth mentioning that their small size also results in high surface activity, leading to significantly impaired stability, which greatly hinders their biomedical utilizations. To overcome this problem, various types of macromolecular materials are utilized to anchor AuNPs so as to achieve advanced synergistic effect by dispersing, protecting, and stabilizing the AuNPs in polymeric-Au hybrid self-assemblies. In this review, the most recent development of polymer-AuNP hybrid systems, including AuNPs@polymeric nanoparticles, AuNPs@polymeric micelle, AuNPs@polymeric film, and AuNPs@polymeric hydrogel are discussed with respect to their different synthetic strategies. These sophisticated materials with diverse functions, oriented toward biomedical applications, are further summarized into several active domains in the areas of drug delivery, gene delivery, photothermal therapy, antibacterials, bioimaging, etc. Finally, the possible approaches for future design of multifunctional polymer-AuNP hybrids by combining hybrid chemistry with biological interface science are proposed.

Parallel multi-parameter study of PEI-functionalized gold nanoparticle synthesis for bio-medical applications: part 1-a critical assessment of methodology, properties, and stability

Cationic polyethyleneimine (PEI)-conjugated gold nanoparticles (AuNPs) that are chemically and physically stable under physiological conditions are an ideal candidate for certain bio-medical applications, in particular DNA transfection. However, the issue remains in reproducibly generating uniform stable species, which can cause the inadequate characterization of the resulting product under relevant conditions and timepoints. The principal objective of the present study was to develop an optimized and reproducible synthetic route for preparing stable PEI-conjugated AuNPs (Au-PEIs). To achieve this objective, a parallel multi-parametric approach involving a total of 96 reaction studies evaluated the importance of 6 key factors: PEI molar mass, PEI structure, molar ratio of PEI/Au, concentration of reaction mixtures, reaction temperature, and reaction time. Application of optimized conditions exhibited narrow size distributions with characteristic surface plasmon resonance absorption and positive surface charge. The optimized Au-PEI product generated by this study exhibits exceptional stability under a physiological isotonic medium (phosphate-buffered saline) over 48 h and shelf-life in ambient condition without any significant change or sedimentation for at least 6 months. Furthermore, the optimized Au-PEI product was highly reproducible. Contributions from individual factors were elucidated using a broad and orthogonal characterization suite examining size and size distribution, optical absorbance, morphological transformation (agglomeration/aggregation), surface functionalities, and stability. Overall, this comprehensive multi-parametric investigation, supported by thorough characterization and rigorous testing, provides a robust foundation for the nanomedicine research community to better synthesize nanomaterials for biomedical use.

Quaternary Ammonium-Terminated Films Formed from Mixed Bidentate Adsorbates Provide a High-Capacity Platform for Oligonucleotide Delivery

The exposure of quaternary ammonium groups on surfaces allows self-assembled monolayers (SAMs) to serve as architectural platforms for immobilizing oligonucleotides. The current study describes the preparation of SAMs derived from four unique bidentate adsorbates containing two different ammonium termini (i.e., trimethyl- and triethyl-) and comparison to their monodentate analogs. Our studies found that SAMs derived from the bidentate adsorbates offered considerable enhancements in oligonucleotide binding when compared to SAMs derived from their monodentate analogs. The generated SAMs were analyzed using ellipsometry, X-ray photoelectron spectroscopy, contact angle goniometry, polarization modulation infrared reflection-absorption spectroscopy, and electrochemical quartz crystal microbalance. These analyses showed that the immobilization of oligonucleotides was affected by changes in the terminal functionalities and the relative packing densities of the monolayers. In efforts to enhance further the immobilization of oligonucleotides on these SAM surfaces, we explored the use of adsorbates having aliphatic linkers with systematically varying chain lengths to form binary SAMs on gold. Mixed monolayers with 50:50 ratios of adsorbates showed the greatest oligonucleotide binding. These studies lay the groundwork for oligonucleotide delivery using gold-based nanoparticles and nanoshells.

Multifunctional hyaluronic acid-derived carbon dots for self-targeted imaging-guided photodynamic therapy

It is of vital importance to engineer the surface structures of carbon dots (CDs) to satisfy their practical biomedical applications, including imaging and treatment. In this work, one type of hyaluronic acid-derived CD (HA-CD) was synthesized via a facile one-step hydrothermal method using cancer cell-targeted HA as a precursor. The as-prepared HA-CDs were targeted actively toward CD44 receptor-overexpressing cancer cells because a partial HA structure remained on the HA-CD surface. Beyond this, HA-CDs can act as a novel photosensitizer, because they can generate O₂˙^- under 650 nm laser irradiation, and they also exhibit excellent blue photoluminescence emission. The in vitro results revealed that HA-CDs imaged selectively CD44-overexpressing cancer cells and inhibited their growth under 650 nm laser irradiation. Thus, HA-CDs can serve as a promising self-targeted imaging-guided photodynamic therapy (PDT) agent for cancer. The present research provides a promising new method to simply construct multifunctional CD-based targeted phototheranostic systems.

Magnetism and photo dual-controlled supramolecular assembly for suppression of tumor invasion and metastasis

Supramolecular nanoassemblies that respond to multiple stimuli exhibit high therapeutic efficacy against malignant tumors. We report a new type of supramolecular nanofiber that integrates targeting peptide-coated magnetic nanoparticles with β-cyclodextrin-bearing polysaccharides in a complex held together by multivalent interactions. The nanofibers not only exhibited reversible photo-triggered association and disassociation depending on irradiation wavelength but also underwent magnetic field-controlled directional aggregation, even in the rather weak geomagnetic field. The nanofibers markedly suppressed invasion by and metastasis of cancer cells both in vitro and in vivo. Furthermore, compared with control mice, tumor-burdened mice treated with the nanofibers showed a lower rate of mortality from the metastatic spread of tumor cells. Our results suggest that these geomagnetism- and photo-controlled nanofibers may facilitate the rapid development of efficacious anticancer therapies.

Reversible Covalent Cross-Linked Polycations with Enhanced Stability and ATP-Responsive Behavior for Improved siRNA Delivery

Cationic polyplex as commonly used nucleic acid carriers faced several shortcomings, such as high cytotoxicity, low serum stability, and slow cargo release at the target site. The traditional solution is covering a negative charged layer (e.g., hyaluronic acid, HA) via electrostatic interaction. However, it was far from satisfactory for the deshielding by physiological anions in circulation (e.g., serum proteins, phosphate). In this study, we proposed a new strategy of reversible covalent cross-linking to enhance stability in circulation and enable stimuli-disassembly of polyplexes in tumor cells. Here, 25k polyethylenimine (PEI) was chosen as model polycations for veriying the hypothesis. HA-PEI conjugation was formed by the cross-linking of adenosine triphosphate grafted HA (HA-ATP) with phenylboronic acid grafted PEI (PEI-PBA) via the chemical reaction between PBA and ATP. Compared with noncovalent polyplex by electrostatic interaction (HA/PEI), HA-PEI exhibited much better colloidal stability and serum stability. The covered HA-ATP layer on PEI-PBA could maintain stable in the absence of physiological anions, while HA layer on PEI in HA/PEI group showed obvious detachment after anion's competition. More importantly, the covalent cross-linking polyplex could selectively release siRNA in the ATP rich environment of cytosol and significantly improve siRNA silence. Besides, the covalent cross-linking with HA-ATP could effectively reduce the cytotoxicity of cationic polyplex, improve the uptake by B61F10 cells and promote the endosomal escape. Consequently, this strategy of HA-PEI conjugation significantly enhanced the siRNA transfection in the absence or presence of FBS (fetal bovine serum) on B16F10 cells and CHO cells. Taken together, the reversible covalent cross-linking approach shows obvious superiority compared with the noncovalent absorption strategy. It held great potential to be developed to polish up the performance of cationic polyplex on reducing the toxicity, enhancing the serum tolerance and achieving controlled release of siRNA at target site.

Stimuli-Responsive Nanocarrier for Co-delivery of MiR-31 and Doxorubicin To Suppress High MtEF4 Cancer

Gene interference-based therapeutics represent a fascinating challenge and show enormous potential for cancer treatment, in which microRNA is used to correct abnormal gene. On the basis of the above, we introduced microRNA-31 to bind to 3'-untranslated region of mtEF4, resulting in the downregulation of its messenger RNA and protein to trigger cancer cells apoptosis through mitochondria-related pathway. To achieve better therapeutic effect, a mesoporous silica nanoparticle-based controlled nanoplatform had been developed. This system was fabricated by conjugation of microRNA-31 onto doxorubicin-loaded mesoporous silica nanoparticles with a poly(ethyleneimine)/hyaluronic acid coating, and drug release was triggered by acidic environment of tumors. By feat of surface functionalization and tumor-specific conjugation to nanoparticles, our drug delivery system could promote intracellular accumulation of drugs via the active transport at tumor site. More importantly, microRNA-31 not only directly targeted to mtEF4 to promote cell's death, but had synergistic effects when used in combination with doxorubicin, and achieved excellent superadditive effects. As such, our research might provide new insights toward detecting high mtEF4 cancer and exploiting highly effective anticancer drugs.

N-halamine-based multilayers on titanium substrates for antibacterial application

Bacterial infection is one of the most severe postoperative complications leading to clinical orthopedic implants failure. To improve the antibacterial property of titanium (Ti) substrates, a bioactive coating composed of chitosan-1-(hydroxymethyl)- 5,5-dimethylhydantoin (Chi-HDH-Cl) and gelatin (Gel) was fabricated via layer-by-layer (LBL) assembly technique. The results of Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (¹HNMR) and X-ray photoelectron spectroscopy (XPS) showed that Chi-HHD-Cl conjugate was successfully synthesized. Scanning electron microscopy (SEM), atomic force microscope (AFM) and water contact angle measurements were employed to monitor the morphology, roughness changes and surface wettability of Ti substrates, which proved the multilayers coating formation. Antibacterial assay against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) revealed that the Gel/Chi-HDH-Cl modified Ti substrates most efficiently inhibited the adhesion and growth of bacteria. Meanwhile, in vitro cellular tests confirmed that Gel/Chi-HDH-Cl multilayers had no obvious cytotoxicity to osteoblasts. The study thus provides a promising method to fabricate antibacterial Ti-based substrates for potential orthopedic application.

Small Delivery Vehicles of siRNA for Enhanced Cancer Targeting

Small interfering RNA (siRNA) drugs have been considered to treat various diseases in major organs. However, siRNA drugs developed for cancer therapy are hindered from proceeding to the clinic. To date, various delivery formulations have been developed from cationic lipids, polymers, and/or inorganic nanoparticles for systemic siRNA delivery to solid tumors. Most of these delivery vehicles do not generate small particle sizes and pharmacokinetics required for accumulation in target cancer cells compared with clinically tested anticancer drug-loaded polymeric micelles. This review describes the significance of small, long-circulating vehicles for efficient delivery of siRNA to cancer tissues via the enhanced permeability and retention (EPR) effect. We summarize recent biological evidence that supports the size effect of delivery vehicles in tumor microenvironments and introduce promising strategies for the construction of small vehicles with sizes of 10-50 nm. We then discuss the feasibility of these delivery vehicles with respect to translation to clinical trials.

Nanomaterials for Cancer Precision Medicine

Medical science has recently advanced to the point where diagnosis and therapeutics can be carried out with high precision, even at the molecular level. A new field of "precision medicine" has consequently emerged with specific clinical implications and challenges that can be well-addressed by newly developed nanomaterials. Here, a nanoscience approach to precision medicine is provided, with a focus on cancer therapy, based on a new concept of "molecularly-defined cancers." "Next-generation sequencing" is introduced to identify the oncogene that is responsible for a class of cancers. This new approach is fundamentally different from all conventional cancer therapies that rely on diagnosis of the anatomic origins where the tumors are found. To treat cancers at molecular level, a recently developed "microRNA replacement therapy" is applied, utilizing nanocarriers, in order to regulate the driver oncogene, which is the core of cancer precision therapeutics. Furthermore, the outcome of the nanomediated oncogenic regulation has to be accurately assessed by the genetically characterized, patient-derived xenograft models. Cancer therapy in this fashion is a quintessential example of precision medicine, presenting many challenges to the materials communities with new issues in structural design, surface functionalization, gene/drug storage and delivery, cell targeting, and medical imaging.

Multifunctional Photonic Nanomaterials for Diagnostic, Therapeutic, and Theranostic Applications

The last decade has seen dramatic progress in the principle, design, and fabrication of photonic nanomaterials with various optical properties and functionalities. Light-emitting and light-responsive nanomaterials, such as semiconductor quantum dots, plasmonic metal nanoparticles, organic carbon, and polymeric nanomaterials, offer promising approaches to low-cost and effective diagnostic, therapeutic, and theranostic applications. Reasonable endeavors have begun to translate some of the promising photonic nanomaterials to the clinic. Here, current research on the state-of-the-art and emerging photonic nanomaterials for diverse biomedical applications is reviewed, and the remaining challenges and future perspectives are discussed.