Improved gene transfer with histidine-functionalized mesoporous silica nanoparticles

Mesoporous silica nanoparticles: An emerging approach in overcoming the challenges with oral delivery of proteins and peptides

Proteins and peptides (PPs), as therapeutics are widely explored in the past few decades, by virtue of their inherent advantages like high specificity and biocompatibility with minimal side effects. However, owing to their macromolecular size, poor membrane permeability, and high enzymatic susceptibility, the effective delivery of PPs is often challenging. Moreover, their subjection to varying environmental conditions, when administered orally, results in PPs denaturation and structural conformation, thereby lowering their bioavailability. Hence, for effective delivery with enhanced bioavailability, protection of PPs using nanoparticle-based delivery system has gained a growing interest. Mesoporous silica nanoparticles (MSNs), with their tailored morphology and pore size, high surface area, easy surface modification, versatile loading capacity, excellent thermal stability, and good biocompatibility, are eligible candidates for the effective delivery of macromolecules to the target site. This review highlights the different barriers hindering the oral absorption of PPs and the various strategies available to overcome them. In addition, the potential benefits of MSNs, along with their diversifying role in controlling the loading of PPs and their release under the influence of specific stimuli, are also discussed in length. Further, the tuning of MSNs for enhanced gene transfection efficacy is also highlighted. Since extensive research is ongoing in this area, this review is concluded with an emphasis on the potential risks of MSNs that need to be addressed prior to their clinical translation.

Drug Delivery Approaches to Improve Tendon Healing

Tendon injuries disrupt the transmission of forces from muscle to bone, leading to chronic pain, disability, and a large socioeconomic burden. Tendon injuries are prevalent; there are over 300,000 tendon repair procedures a year in the United States to address acute trauma or chronic tendinopathy. Successful restoration of function after tendon injury remains challenging clinically. Despite improvements in surgical and physical therapy techniques, the high complication rate of tendon repair procedures motivates the use of therapeutic interventions to augment healing. While many biological and tissue engineering approaches have attempted to promote scarless tendon healing, there is currently no standard clinical treatment to improve tendon healing. Moreover, the limited efficacy of systemic delivery of several promising therapeutic candidates highlights the need for tendon-specific drug delivery approaches to facilitate translation. This review article will synthesize the current state-of-the-art methods that have been used for tendon-targeted delivery through both systemic and local treatments, highlight emerging technologies used for tissue-specific drug delivery in other tissue systems, and outline future challenges and opportunities to enhance tendon healing through targeted drug delivery.

Dendritic Mesoporous Organosilica Nanoparticles with Photosensitizers for Cell Imaging, siRNA Delivery and Protein Loading

Dendritic mesoporous organosilica nanoparticles (DMON) are a new class of biodegradable nanoparticles suitable for biomolecule delivery. We studied the photochemical internalization (PCI) and photodynamic therapy (PDT) of DMON to investigate new ways for DMON to escape from the endosomes-lysosomes and deliver biomolecules into the cytoplasm of cells. We added photosensitizers in the framework of DMON and found that DMON were loaded with siRNA or FVIII factor protein. We made four formulations with four different photosensitizers. The photosensitizers allowed us to perform imaging of DMON in cancer cells, but the presence of the tetrasulfide bond in the framework of DMON quenched the formation of singlet oxygen. Fortunately, one formulation allowed us to efficiently deliver proapoptotic siRNA in MCF-7 cancer cells leading to 31% of cancer cell death, without irradiation. As for FVIII protein, it was loaded in two formulations with drug-loading capacities (DLC) up to 25%. In conclusion, DMON are versatile nanoparticles capable of loading siRNA and delivering it into cancer cells, and also loading FVIII protein with good DLC. Due to the presence of tetrasulfide, it was not possible to perform PDT or PCI.

An overview of the material science and knowledge of nanomedicine, bioscaffolds, and tissue engineering for tendon restoration

Tendon wounds are a worldwide health issue affecting millions of people annually. Due to the characteristics of tendons, their natural restoration is a complicated and lengthy process. With the advancement of bioengineering, biomaterials, and cell biology, a new science, tissue engineering, has developed. In this field, numerous ways have been offered. As increasingly intricate and natural structures resembling tendons are produced, the results are encouraging. This study highlights the nature of the tendon and the standard cures that have thus far been utilized. Then, a comparison is made between the many tendon tissue engineering methodologies proposed to date, concentrating on the ingredients required to gain the structures that enable appropriate tendon renewal: cells, growth factors, scaffolds, and scaffold formation methods. The analysis of all these factors enables a global understanding of the impact of each component employed in tendon restoration, thereby shedding light on potential future approaches involving the creation of novel combinations of materials, cells, designs, and bioactive molecules for the restoration of a functional tendon.

Stimuli-Responsive Multifunctional Nanomedicine for Enhanced Glioblastoma Chemotherapy Augments Multistage Blood-to-Brain Trafficking and Tumor Targeting

Minimal therapeutic advances have been achieved over the past two decades for glioblastoma (GBM), which remains an unmet clinical need. Here, hypothesis-driven stimuli-responsive nanoparticles (NPs) for docetaxel (DTX) delivery to GBM are reported, with multifunctional features that circumvent insufficient blood-brain barrier (BBB) trafficking and lack of GBM targeting-two major hurdles for anti-GBM therapies. NPs are dual-surface tailored with a i) brain-targeted acid-responsive Angiopep-2 moiety that triggers NP structural rearrangement within BBB endosomal vesicles, and ii) L-Histidine moiety that provides NP preferential accumulation into GBM cells post-BBB crossing. In tumor invasive margin patient cells, the stimuli-responsive multifunctional NPs target GBM cells, enhance cell uptake by 12-fold, and induce three times higher cytotoxicity in 2D and 3D cell models. Moreover, the in vitro BBB permeability is increased by threefold. A biodistribution in vivo trial confirms a threefold enhancement of NP accumulation into the brain. Last, the in vivo antitumor efficacy is validated in GBM orthotopic models following intratumoral and intravenous administration. Median survival and number of long-term survivors are increased by 50%. Altogether, a preclinical proof of concept supports these stimuli-responsive multifunctional NPs as an effective anti-GBM multistage chemotherapeutic strategy, with ability to respond to multiple fronts of the GBM microenvironment.

Glioblastoma immuno-endothelial multicellular microtissue as a 3D in vitro evaluation tool of anti-cancer nano-therapeutics

Despite being the most prevalent and lethal type of adult brain cancer, glioblastoma (GBM) remains intractable. Promising anti-GBM nanoparticle (NP) systems have been developed to improve the anti-cancer performance of difficult-to-deliver therapeutics, with particular emphasis on tumor targeting strategies. However, current disease modeling toolboxes lack close-to-native in vitro models that emulate GBM microenvironment and bioarchitecture, thus partially hindering translation due to poorly predicted clinical responses. Herein, human GBM heterotypic multicellular tumor microtissues (MCTMs) are generated through high-throughput 3D modeling of U-251 MG tumor cells, tissue differentiated macrophages isolated from peripheral monocytes, and brain microvascular primary endothelial cells. GBM MCTMs mimicked tumor spatial organization, extracellular matrix production and necrosis areas. The bioactivity of a model drug, docetaxel (DTX), and of tumor-targeted DTX-loaded polymeric NPs with a surface L-Histidine moiety (H-NPs), were assessed in the MCTMs. MCTMs cell uptake and anti-proliferative effect was 8- and 3-times higher for H-NPs, respectively, compared to the non-targeted NPs and to free DTX. H-NPs provided a decrease of MCTMs anti-inflammatory M2-macrophages, while increasing their pro-inflammatory M1 counterparts. Moreover, H-NPs showed a particular biomolecular signature through reduced secretion of an array of medium cytokines (IFN-γ, IL-1β, IL-1Ra, IL-6, IL-8, TGF-β). Overall, MCTMs provide an in vitro biomimetic model to recapitulate key cellular and structural features of GBM and improve in vivo drug response predictability, fostering future clinical translation of anti-GBM nano-therapeutic strategies.

Non-Viral Delivery of Gene Therapy to the Tendon

The tendon, as a compact connective tissue, is difficult to treat after an acute laceration or chronic degeneration. Gene-based therapy is a highly efficient strategy for diverse diseases which has been increasingly applied in tendons in recent years. As technology improves by leaps and bounds, a wide variety of non-viral vectors have been manufactured that attempt to have high biosecurity and transfection efficiency, considered to be a promising treatment modality. In this review, we examine the unwanted biological barriers, the categories of applicable genes, and the introduction and comparison of non-viral vectors. We focus on lipid-based nanoparticles and polymer-based nanoparticles, differentiating between them based on their combination with diverse chemical modifications and scaffolds.

Tendon Tissue Repair in Prospective of Drug Delivery, Regenerative Medicines, and Innovative Bioscaffolds

The natural healing capacity of the tendon tissue is limited due to the hypovascular and cellular nature of this tissue. So far, several conventional approaches have been tested for tendon repair to accelerate the healing process, but all these approaches have their own advantages and limitations. Regenerative medicine and tissue engineering are interdisciplinary fields that aspire to develop novel medical devices, innovative bioscaffold, and nanomedicine, by combining different cell sources, biodegradable materials, immune modulators, and nanoparticles for tendon tissue repair. Different studies supported the idea that bioscaffolds can provide an alternative for tendon augmentation with an enormous therapeutic potentiality. However, available data are lacking to allow definitive conclusion on the use of bioscaffolds for tendon regeneration and repairing. In this review, we provide an overview of the current basic understanding and material science in the field of bioscaffolds, nanomedicine, and tissue engineering for tendon repair.

The Multifaceted Histidine-Based Carriers for Nucleic Acid Delivery: Advances and Challenges

Histidines incorporated into carriers of nucleic acids may enhance the extracellular stability of the nanoparticle, yet aid in the intracellular disruption of the nanoparticle, enabling the release of the nucleic acid. Moreover, protonation of histidines in the endosomes may result in endosomal swelling with subsequent lysis. These properties of histidine are based on its five-member imidazole ring in which the two nitrogen atoms may form hydrogen bonds or act as a base in acidic environments. A wide variety of carriers have integrated histidines or histidine-rich domains, which include peptides, polyethylenimine, polysaccharides, platform delivery systems, viral phages, mesoporous silica particles, and liposomes. Histidine-rich carriers have played key roles in our understanding of the stability of nanocarriers and the escape of the nucleic acids from endosomes. These carriers show great promise and offer marked potential in delivering plasmids, siRNA, and mRNA to their intracellular targets.

Silica-Based Gene Delivery Systems: From Design to Therapeutic Applications

Advances in gene therapy have been foreshadowing its potential for the treatment of a vast range of diseases involving genetic malfunctioning. However, its therapeutic efficiency and successful outcome are highly dependent on the development of the ideal gene delivery system. On that matter, silica-based vectors have diverted some attention from viral and other types of non-viral vectors due to their increased safety, easily modifiable structure and surface, high stability, and cost-effectiveness. The versatility of silane chemistry and the combination of silica with other materials, such as polymers, lipids, or inorganic particles, has resulted in the development of carriers with great loading capacities, ability to effectively protect and bind genetic material, targeted delivery, and stimuli-responsive release of cargos. Promising results have been obtained both in vitro and in vivo using these nanosystems as multifunctional platforms in different potential therapeutic areas, such as cancer or brain therapies, sometimes combined with imaging functions. Herein, the current advances in silica-based systems designed for gene therapy are reviewed, including their main properties, fabrication methods, surface modifications, and potential therapeutic applications.

Mesoporous Silica Nanoparticles for Co-Delivery of Drugs and Nucleic Acids in Oncology: A Review

Mesoporous silica nanoparticles have attracted much attention in recent years as drug and gene delivery systems for biomedical applications. Among their most beneficial features for biomedicine, we can highlight their biocompatibility and their outstanding textural properties, which provide a great loading capacity for many types of cargos. In the context of cancer nanomedicine, combination therapy and gene transfection/silencing have recently been highlighted as two of its most promising fields. In this review, we aim to provide an overview of the different small molecule drug-nucleic acid co-delivery combinations that have been developed using mesoporous silica nanoparticles as carriers. By carefully selecting the chemotherapeutic drug and nucleic acid cargos to be co-delivered by mesoporous silica nanoparticles, different therapeutic goals can be achieved by overcoming resistance mechanisms, combining different cytotoxic mechanisms, or providing an additional antiangiogenic effect. The examples here presented highlight the great promise of this type of strategies for the development of future therapeutics.

Co-condensation synthesis of well-defined mesoporous silica nanoparticles: effect of surface chemical modification on plasmid DNA condensation and transfection

Chemically modified mesoporous silica nanoparticles (MSNs) are of interest due to their chemical and thermal stability with adjustable morphology and porosity; therefore, it was aimed to develop and compare the MCM-41 MSNs functionalised with imidazole groups (MCM-41-Im) to unmodified (MCM-41-OH) and primary amine functionalised (MCM-41-NH₂) MSNs for experimental gene delivery. The results show efficient transfection of the complexes of the plasmid and either MCM-41-NH₂ or MCM-41-Im. Furthermore, following transfection of HeLa cells using MCM-41-Im, an enhanced GFP expression was achieved consistent with the noticeable DNase1 protection and endosomal escape properties of MCM-41-Im using carboxyfluorescein tracer.

Mesoporous Silica Nanomaterials: Versatile Nanocarriers for Cancer Theranostics and Drug and Gene Delivery

Mesoporous silica nanomaterials (MSNs) have made remarkable achievements and are being thought of by researchers as materials that can be used to effect great change in cancer therapies, gene delivery, and drug delivery because of their optically transparent properties, flexible size, functional surface, low toxicity profile, and very good drug loading competence. Mesoporous silica nanoparticles (MSNPs) show a very high loading capacity for therapeutic agents. It is well known that cancer is one of the most severe known medical conditions, characterized by cells that grow and spread rapidly. Thus, curtailing cancer is one of the greatest current challenges for scientists. Nanotechnology is an evolving field of study, encompassing medicine, engineering, and science, and it has evolved over the years with respect to cancer therapy. This review outlines the applications of mesoporous nanomaterials in the field of cancer theranostics, as well as drug and gene delivery. MSNs employed as therapeutic agents, as well as their importance and future prospects in the ensuing generation of cancer theranostics and drug and therapeutic gene delivery, are discussed herein. Thus, the use of mesoporous silica nanomaterials can be seen as using one stone to kill three birds.

Mesoporous silica nanoparticles for drug and gene delivery

Mesoporous silica nanoparticles (MSNs) are attracting increasing interest for potential biomedical applications. With tailored mesoporous structure, huge surface area and pore volume, selective surface functionality, as well as morphology control, MSNs exhibit high loading capacity for therapeutic agents and controlled release properties if modified with stimuli-responsive groups, polymers or proteins. In this review article, the applications of MSNs in pharmaceutics to improve drug bioavailability, reduce drug toxicity, and deliver with cellular targetability are summarized. Particularly, the exciting progress in the development of MSNs-based effective delivery systems for poorly soluble drugs, anticancer agents, and therapeutic genes are highlighted.

Porous Inorganic Drug Delivery Systems-a Review

Innovative methods and materials have been developed to overcome limitations associated with current drug delivery systems. Significant developments have led to the use of a variety of materials (as excipients) such as inorganic and metallic structures, marking a transition from conventional polymers. Inorganic materials, especially those possessing significant porosity, are emerging as good candidates for the delivery of a range of drugs (antibiotics, anticancer and anti-inflammatories), providing several advantages in formulation and engineering (encapsulation of drug in amorphous form, controlled delivery and improved targeting). This review focuses on key selected developments in porous drug delivery systems. The review provides a short broad overview of porous polymeric materials for drug delivery before focusing on porous inorganic materials (e.g. Santa Barbara Amorphous (SBA) and Mobil Composition of Matter (MCM)) and their utilisation in drug dosage form development. Methods for their preparation and drug loading thereafter are detailed. Several examples of porous inorganic materials, drugs used and outcomes are discussed providing the reader with an understanding of advances in the field and realistic opportunities.

Improved Gene Transfer with Functionalized Hollow Mesoporous Silica Nanoparticles of Reduced Cytotoxicity

Gene therapy is a promising strategy for treatment of genetically caused diseases. Successful gene delivery requires an efficient carrier to transfer the desired gene into host cells. Recently, mesoporous silica nanoparticles (MSNs) functionalized with 25 kD polyethyleneimine (PEI) were extensively used as gene delivery carriers. However, 25 kD PEI could significantly reduce the safety of the modified MSNs although it is efficient for intracellular delivery of nucleic acids. In addition, limited drug loading remains a challenge for conventional MSNs drug carriers. Hollow mesoporous silica nanoparticles (HMSNs) with high pore volume, tunable pore size, and excellent biocompatibility are attractive alternatives. To make them more efficient, a less toxic 1.8 kD PEI polymer was used to functionalize the HMSNs which have large pore size (~10 nm) and form PEI-HMSNs. Scanning and transmission electron microscopic images showed that HMSNs were spherical in shape and approximately 270 nm in diameter with uniform hollow nanostructures. The maximum loading capacity of green fluorescent protein labeled DNA (GFP-DNA) in PEI-HMSNs was found to be 37.98 mg/g. The loading capacity of PEI-HMSNs was nearly three-fold higher than those of PEI modified solid nanoparticles, indicating that both hollow and large pores contributed to the increase in DNA adsorption. The transfection of GFP-DNA plasmid loaded in PEI-HMSNs was increased two-fold in comparison to that of 25 kD PEI. MTT assays in Lovo cells showed that the cell viability was more than 85% when the concentration of PEI-HMSNs was 120 µg/mL, whereas the cell viability was less than 20% when the 25 kD PEI was used at the same concentration. These results indicated that PEI-HMSNs could be used as a delivery system for nucleic acids due to good biocompatibility, high gene loading capacity, and enhanced gene transfer efficiency.

Mesoporous Silica Nanoparticles as Carriers for Intracellular Delivery of Nucleic Acids and Subsequent Therapeutic Applications

Nucleic acids, including DNA, microRNA (miRNA), small interfering RNA (siRNA), and antisense oligonucleotide (ASO), are powerful gene regulators, which have been demonstrated as promising drug candidates for therapeutic treatments. Nevertheless, poor cellular membrane permeability and serum stability have greatly hindered the applications of nucleic acids in biomedicine. To address these issues, associate carriers that can encapsulate and protect nucleic acids are urgently required. Mesoporous silica nanoparticles (MSNs or MSNPs), which are nanomaterials with excellent biocompatibility, large surface area for functionalization, and tunable pore size for encapsulating different cargos, are emerging as novel and ideal biomaterials for different biomedical applications. In this review paper, we focus on the applications of MSNs in nucleic acid delivery and nucleic acid-guided therapeutic treatments. General strategies for the preparation of nucleic acid-MSN complexes will be firstly introduced, followed by a summary of recent applications of MSNs in nucleic acid delivery and nucleic acid-guided therapeutics.

A mesoporous organosilica nano-bowl with high DNA loading capacity - a potential gene delivery carrier

Mesoporous organosilica nanoparticles with a novel bowl-like morphology were synthesized. These nano-bowls possess uniform particle sizes around 180 nm and open cavities around 140 nm, which lead to higher loading capability for plasmid DNA than traditional silica-based nanoparticles. In vitro DNA transfection using these nano-bowls is demonstrated.

Nanoparticles for Tendon Healing and Regeneration: Literature Review

Tendon injuries are commonly met in the emergency department. Unfortunately, tendon tissue has limited regeneration potential and usually the consequent formation of scar tissue causes inferior mechanical properties. Nanoparticles could be used in different way to improve tendon healing and regeneration, ranging from scaffolds manufacturing (increasing the strength and endurance or anti-adhesions, anti-microbial, and anti-inflammatory properties) to gene therapy. This paper aims to summarize the most relevant studies showing the potential application of nanoparticles for tendon tissue regeneration.

Functionalized Mesoporous Silica Nanoparticle with Antioxidants as a New Carrier That Generates Lower Oxidative Stress Impact on Cells

Mesoporous silica nanoparticles (MSNs) were covalently coated with antioxidant molecules, namely, caffeic acid (MSN-CAF) or rutin (MSN-RUT), in order to diminish the impact of oxidative stress induced after transfection into cells, thus generating safer carriers used for either drug delivery or other applications. Two cellular models involved in the entry of NPs in the body were used for this purpose: the intestinal Caco-2 and the epidermal HaCaT cell lines. Rutin gave the best results in terms of antioxidant capacities preservation during coupling procedures, cellular toxicity alleviation, and decrease of ROS level after 24 h incubation of cells with grafted nanoparticles. These protective effects of rutin were found more pronounced in HaCaT than in Caco-2 cells, indicating some cellular specificity toward defense against oxidative stress. In order to gain more insight about the Nrf2 response, a stable transfected HaCaT cell line bearing repeats of the antioxidant response element (ARE) in front of a luciferase reporter gene was generated. In this cell line, both tBHQ and quercetin (Nrf2 agonists), but not rutin, were able to induce, in a dose-dependent fashion, the luciferase response. Interestingly, at high concentration, MSN-RUT was able to induce a strong Nrf2 protective response in HaCaT cells, accompanied by a comparable induction of HO-1 mRNA. The level of these responses was again less important in Caco-2 cells. To conclude, in keratinocyte cell line, the coupling of rutin to silica nanoparticles was beneficial in term of ROS reduction, cellular viability, and protective effects mediated through the activation of the Nrf2 antioxidant pathway.

Gene therapy strategies to improve strength and quality of flexor tendon healing

INTRODUCTION

Rupture of the repair and adhesion around a tendon are two major problems after tendon surgery. Novel biological therapies which enhance healing and reduce adhesions are goals of many investigations. Gene therapy offers a new and promising approach to tackle these difficult problems. In the past decade, we sought to develop methods to augment tendon healing and reduce tendon adhesion through gene therapy.

AREAS COVERED

This review discusses the methods and results of adeno-associated viral (AAV) type 2 vector gene therapy to increase tendon healing strength and reduce adhesions in a chicken model. Micro-RNA related gene therapy is also discussed. We also developed a controlled release system, which incorporates nanoparticles to deliver micro-RNAs to regulate tendon healing.

EXPERT OPINION

We obtained promising results of enhancement of tendon healing strength in a chicken model using AAV2-mediated gene transfer. AAV2-mediated micro-RNA transfer also limited adhesions around the tendon. Controlled release systems incorporating nanoparticles have ideally delivered genes to the healing tendons and resulted in a moderate (but incomplete) reduction of adhesions. It remains to be determined what the best doses are and what other factors are in play in adhesion formation. These are two targets in our future investigations.