Magnetic graphene oxide nanoflakes for dual RNA interfering delivery and gene knockdown in prostate and liver cancers

The development of synthetic carriers for small interfering RNA (siRNA) and plasmids is crucial for effective gene therapy. In this study, we synthesized magnetic graphene oxide nanoflakes as carriers for siRNA delivery, with the goal of knockdown specific genes such as the green fluorescence protein (GFP). Our approach combined magnetically reduced graphene oxide with polyethylenimine (PEI) crosslinked to its surface using carbonyl diimidazole. To evaluate the adsorption capacity of the PEI-modified nanocomposite, we investigated its ability to bind two types of nucleic acids: short-hairpin (sh)RNA plasmids and siRNA targeting GFP. The nanocomposite exhibited significant adsorption, with maximum capacities of 426 ng/μg for shRNA and 71 ng/μg for siRNA, respectively. Simultaneous delivery of siRNA and shRNA using our designed nanocomposites was successfully achieved in human hepatoma and prostate cancer cells. Under magnetic guidance, the knockdown efficiencies reached 73.5 % in hepatoma cells for dual delivery of siRNA and shRNA. Our findings revealed that the nanocomplexes were internalized by the cells through a caveolae-dependent endocytosis mechanism. The demonstrated ability of the nanoflakes to efficiently transport siRNA and shRNA, with high loading capacity, controlled release, and magnetic targeting, resulted in effective GFP knockdown in vitro. These findings highlight the potential of magnetic graphene oxide nanoflakes as promising carriers for siRNA delivery and gene knockdown in therapeutic applications.

Dual scaffold delivery of miR-210 mimic and miR-16 inhibitor enhances angiogenesis and osteogenesis to accelerate bone healing

Angiogenesis is critical for successful bone repair, and interestingly, miR-210 and miR-16 possess counter-active targets involved in both angiogenesis and osteogenesis: miR-210 acts as an activator by silencing EFNA3 & AcvR1b, while miR-16 inhibits both pathways by silencing VEGF & Smad5. It was thus hypothesized that dual delivery of both a miR-210 mimic and a miR-16 inhibitor from a collagen-nanohydroxyapatite scaffold system may hold significant potential for bone repair. Therefore, this systems potential to rapidly accelerate bone repair by directing enhanced angiogenic-osteogenic coupling in host cells in a rat calvarial defect model at a very early 4 week timepoint was assessed. In vitro, the treatment significantly enhanced angiogenic-osteogenic coupling of human mesenchymal stem cells, with enhanced calcium deposition after just 10 days in 2D and 14 days on scaffolds. In vivo, these dual-miRNA loaded scaffolds showed more than double bone volume and vessel recruitment increased 2.3 fold over the miRNA-free scaffolds. Overall, this study demonstrates the successful development of a dual-miRNA mimic/inhibitor scaffold for enhanced in vivo bone repair for the first time, and the possibility of extending this 'off-the-shelf' platform system to applications beyond bone offers immense potential to impact a myriad of other tissue engineering areas. STATEMENT OF SIGNIFICANCE: miRNAs have potential as a new class of bone healing therapeutics as they can enhance the regenerative capacity of bone-forming cells. However, angiogenic-osteogenic coupling is critical for successful bone repair. Therefore, this study harnesses the delivery of miR-210, known to be an activator of both angiogenesis and osteogenesis, and miR-16 inhibitor, as miR-16 is known to inhibit both pathways, from a collagen-nanohydroxyapatite scaffold system to rapidly enhance osteogenesis in vitro and bone repair in vivo in a rat calvarial defect model. Overall, it describes the successful development of the first dual-miRNA mimic/inhibitor scaffold for enhanced in vivo bone repair. This 'off-the-shelf' platform system offers immense potential to extend beyond bone applications and impact a myriad of other tissue engineering areas.

Co-delivery of simvastatin and microRNA-21 through liposome could accelerates the wound healing process

The gene delivery approach, mainly microRNAs (miRNA) as key wound healing mediators, has recently received extensive attention. MicroRNA-21 (miR-21) has strongly impacted wound healing by affecting the inflammation and proliferation phases. Previous studies have also demonstrated the beneficial effect of simvastatin on wound healing. Therefore, we designed a dual-drug/gene delivery system using PEGylated liposomes that could simultaneously attain the co-encapsulation and co-delivery of miRNA and simvastatin (SIM) to explore the combined effect of this dual-drug delivery system on wound healing. The PEG-liposomes for simvastatin and miR-21 plasmid (miR-21-P/SIM/Liposomes) were prepared using the thin-film hydration method. The liposomes showed 85 % entrapment efficiency for SIM in the lipid bilayer and high physical entrapment of miR-21-P in the inner cavity. In vitro studies demonstrated no cytotoxicity for the carrier on normal human dermal fibroblast cells (NHDF) and 97 % cellular uptake over 2 h incubation. The scratch test revealed excellent cell proliferation and migration after treatment with miR-21-P/SIM/Liposomes. For the in vivo experiments, a full-thickness cutaneous wound model was used. The wound closure on day 8 was higher for Liposomal formulation containing miR-21-P promoting faster re-epithelialization. On day 12, all treated groups showed complete wound closure. However, following histological analysis, the miR-21-P/SIM/Liposomes revealed the best tissue regeneration, similar to normal functional skin, by reduced inflammation and increased re-epithelialization, collagen deposition and angiogenesis. In conclusion, the designed miR-21-P/SIM/Liposomes could significantly accelerate the process of wound healing, which provides a new strategy for the management of chronic wounds.

Local dual delivery therapeutic strategies: Using biomaterials for advanced bone tissue regeneration

Bone development is a complex process involving a vast number of growth factors and chemical substances. These factors include transforming growth factor-beta, platelet-derived growth factor, insulin-like growth factor, and most importantly, the bone morphogenetic protein, which exhibits excellent therapeutic value in bone repair. However, the spatial-temporal relationship in the expression of these factors during bone formation makes the bone repair a more complicated process to address. Thus, using a single therapeutic agent to address bone formation does not seem to provide a clinically effective option. Conversely, a dual delivery approach facilitating the co-delivery of agents has proved to be a dynamic alternative since such a strategy can provide more efficient spatial-temporal action. Such delivery systems can smartly target more than one pathway or differentiation lineage and thus offer more efficient bone regeneration. This review discusses various dual delivery strategies reported in the literature employed to achieve improved bone regeneration. These include concurrent use of different therapeutic agents (including growth factors and drugs), enhancing bone formation and cell recruitment, and improving the efficiency of bone healing.

New insights into Hexakis macrocycles as a novel nano-carrier for highly potent anti-cancer treatment: A new challenge in drug delivery

The purpose of this study is to design and evaluate a new tubular assembly structure of Hexakis (m-phenylene ethynylene) (m-PE) macrocycles and to explore its potential application as an innovative drug delivery system. First, we focused on how (m-PE) macrocycles can be self-assembled in both chloroform (CHCl₃) and water solvents for the formation of the assembled nanotube using molecular dynamics (MD) simulations. In contrast to their behavior in water solvent, all ten (m-PE) macrocycles remain aggregated at low concentrations of CHCl₃. We found that these macrocycles carrying chiral side chains and capable of H-bonded self-association, assemble into tubular stacks. Then, the dual delivery strategy for the transport of doxorubicin (DOX) and curcumin (Cur) on the self-assembly system of hexakis (m-PE) nanocarrier is examined using molecular dynamics (MD) simulation and free energy calculation. The obtained results indicated that the binding energy of DOX (- 298.9 kJ/mol) on hexakis (m-PE) in the presence of Cur is higher than free DOX (- 247.7 kJ/mol). Furthermore, in the interaction of the DOX and hexakis m-PE, the contribution of van der Walls (vdW) energy is higher than electrostatic (elec) energy, which can be related to the strong π-π interactions between the drug molecules with the carrier surface. In general, the results indicated that the simultaneous delivery of DOX and Cur through DOX/Cur/hexakis (m-PE) could be a promising vehicle in tumor therapy. Based on the obtained results of the present research, hexakis (m-PE) macrocycle can be used as a drug delivery vehicle for targeted or systemic delivery.

Combined delivery of bone morphogenetic protein-2 and insulin-like growth factor-1 from nano-poly (γ-glutamic acid)/β-tricalcium phosphate-based calcium phosphate cement and its effect on bone regeneration in vitro

In this study, nano-doped calcium phosphate cement delivery systems (poly (γ-glutamic acid)/β-tricalcium phosphate/calcium phosphate ceramics and nano (γ-glutamic acid)/β-tricalcium phosphate/calcium phosphate ceramic) were fabricated, and low doses (10 µg/g) of two growth factors, insulin-like growth factor-1 and bone morphogenetic protein-2, were encapsulated then sequentially released. We characterized the delivery systems using Fourier transform infrared spectroscopy and X-ray diffraction and measured washout resistance and compressive strength, and thus optimized the most appropriate proportioning of delivery systems for the two growth factors. One of the growth factors was absorbed by the nano-poly (γ-glutamic acid)/β-tricalcium phosphate, which was then mixed into the calcium phosphate ceramic solid phase to create a new solid phase calcium phosphate ceramic. Nano-poly (γ-glutamic acid)/β-tricalcium phosphate/calcium phosphate ceramic carriers were then prepared by blending the new calcium phosphate ceramic solid phase powder with a solution of the remaining growth factor. The effects of different release patterns (studying sequential behavior) of insulin-like growth factor-1 and bone morphogenetic protein-2 on osteogenic proliferation and differentiation of the MC3t3-E1 mouse osteoblast cell were investigated. This combinational delivery system provided a controlled release of the two growth factors, in which nano-doping significantly affected their release kinetics. The incorporation of dual growth factors could potentially stimulate bone healing and promoting bone ingrowth processes at a low dose.

Additive potential of combination therapy against cryptococcosis employing a novel amphotericin B and fluconazole loaded dual delivery system

Cryptococcus neoformans is one of the most lethal fungi causing mortality across the globe. Immuno-competent patients and patients taking immuno-suppressive medications are extremely susceptible to its infection. For effective removal of cryptococcal burden, there is an urgent need for new forms of therapy. In the present study, we have explored the potential effects of amphotericin B (AMB) and fluconazole (FLC) in combination, against cryptococcosis in Swiss albino mice. To enhance the therapeutic potential of the tested drugs, they were entrapped into fibrin microspheres; a dual delivery vehicle comprising of poly-lactide co-glycolide (PLGA) microsphere that was additionally encapsulated into the fibrin cross-linked plasma bead. Dynamics of fibrin microspheres included survival and fungal burden in lung, liver and spleen of treated mice. While each drug was effective in combination or alone, prominent additive potential of AMB and FLC were clearly observed when used in fibrin microsphere. Significant reduction in fungal burden and increase in survival rate of AMB + FLC-fibrin microspheres treated mice shows an extensive accessibility of both tested drugs without any side-effects. A full potential of two-drug combination encapsulated in fibrin microspheres proposes an effective approach of safe delivery to the target site in their intact form and decrease the drug associated toxicities.

Microfluidic assembly of a nano-in-micro dual drug delivery platform composed of halloysite nanotubes and a pH-responsive polymer for colon cancer therapy

Harsh conditions of the gastrointestinal tract hinder the oral delivery of many drugs. Developing oral drug delivery systems based on commercially available materials is becoming more challenging due to the demand for simultaneously delivering physicochemically different drugs for treating complex diseases. A novel architecture, namely nanotube-in-microsphere, was developed as a drug delivery platform by encapsulating halloysite nanotubes (HNTs) in a pH-responsive hydroxypropyl methylcellulose acetate succinate polymer using microfluidics. HNTs were selected as orally acceptable clay mineral and their lumen was enlarged by selective acid etching. Model drugs (atorvastatin and celecoxib) with different physicochemical properties and synergistic effect on colon cancer prevention and inhibition were simultaneously incorporated into the microspheres at a precise ratio, with atorvastatin and celecoxib being loaded in the HNTs and polymer matrix, respectively. The microspheres showed spherical shape, narrow particle size distribution and pH-responsive dissolution behavior. This nanotube/pH-responsive polymer composite protected the loaded drugs from premature release at pH⩽6.5, but allowed their fast release and enhanced the drug permeability, and the inhibition of colon cancer cell proliferation at pH 7.4. Overall, the nano-in-micro drug delivery composite fabricated by microfluidics is a promising and flexible platform for the delivery of multiple drugs for combination therapy.

STATEMENT OF SIGNIFICANCE

Halloysite nanotubes (HNTs) are attracting increasing attention for drug delivery applications. However, conventional HNTs-based oral drug delivery systems are lack of the capability to precisely control the drug release at a desired site in the gastrointestinal tract. In this study, a nanotube-in-microsphere drug delivery platform is developed by encapsulating HNTs in a pH-responsive polymer using microfluidics. Drugs with different physicochemical properties and synergistic effect on colon cancer therapy were simultaneously incorporated in the microspheres. The prepared microspheres prevented the premature release of the loaded drugs after exposure to the harsh conditions of the gastrointestinal tract, but allowed their simultaneously fast release, and enhanced the drug permeability and the inhibition of colon cancer cell proliferation in response to the colon pH.

Dual delivery of biological therapeutics for multimodal and synergistic cancer therapies

Cancer causes >8.2 million deaths annually worldwide; thus, various cancer treatments have been investigated over the past decades. Among them, combination drug therapy has become extremely popular, and treatment with more than one drug is often necessary to achieve appropriate anticancer efficacy. With the development of nanoformulations and nanoparticulate-based drug delivery, researchers have explored the feasibility of dual delivery of biological therapeutics to overcome the current drawbacks of cancer therapy. Compared with the conventional single drug therapy, dual delivery of therapeutics has provided various synergistic effects in addition to offering multimodality to cancer treatment. In this review, we highlight and summarize three aspects of dual-delivery systems for cancer therapy. These include (1) overcoming drug resistance by the dual delivery of chemical drugs with biological therapeutics for synergistic therapy, (2) targeted and controlled drug release by the dual delivery of drugs with stimuli-responsive nanomaterials, and (3) multimodal theranostics by the dual delivery of drugs and molecular imaging probes. Furthermore, recent developments, perspectives, and new challenges regarding dual-delivery systems for cancer therapy are discussed.