Layer-by-layer nanoparticles as an efficient siRNA delivery vehicle for SPARC silencing

Polypeptide-based multilayer nanoarchitectures: Controlled assembly on planar and colloidal substrates for biomedical applications

Polypeptides have shown an excellent potential in nanomedicine thanks to their biocompatibility, biodegradability, high functionality, and responsiveness to several stimuli. Polypeptides exhibit high propensity to organize at the supramolecular level; hence, they have been extensively considered as building blocks in the layer-by-layer (LbL) assembly. The LbL technique is a highly versatile methodology, which involves the sequential assembly of building blocks, mainly driven by electrostatic interactions, onto planar or colloidal templates to fabricate sophisticated multilayer nanoarchitectures. The simplicity and the mild conditions required in the LbL approach have led to the inclusion of biopolymers and bioactive molecules for the fabrication of a wide spectrum of biodegradable, biocompatible, and precisely engineered multilayer films for biomedical applications. This review focuses on those examples in which polypeptides have been used as building blocks of multilayer nanoarchitectures for tissue engineering and drug delivery applications, highlighting the characteristics of the polypeptides and the strategies adopted to increase the stability of the multilayer film. Cross-linking is presented as a powerful strategy to enhance the stability and stiffness of the multilayer network, which is a fundamental requirement for biomedical applications. For example, in tissue engineering, a stiff multilayer coating, the presence of adhesion promoters, and/or bioactive molecules boost the adhesion, growth, and differentiation of cells. On the contrary, antimicrobial coatings should repel and inhibit the growth of bacteria. In drug delivery applications, mainly focused on particles and capsules at the micro- and nano-meter scale, the stability of the multilayer film is crucial in terms of retention and controlled release of the payload. Recent advances have shown the key role of the polypeptides in the adsorption of genetic material with high loading efficiency, and in addressing different pathways of the particles/capsules during the intracellular uptake, paving the way for applications in personalized medicine. Although there are a few studies, the responsiveness of the polypeptides to the pH changes, together with the inclusion of stimuli-responsive entities into the multilayer network, represents a further key factor for the development of smart drug delivery systems to promote a sustained release of therapeutics. The degradability of polypeptides may be an obstacle in certain scenarios for the controlled intracellular release of a drug once an external stimulus is applied. Nowadays, the highly engineered design of biodegradable LbL particles/capsules is oriented on the development of theranostics that, limited to use of polypeptides, are still in their infancy.

Stability and programmed sequential release of Lactobacillus plantarum and curcumin encapsulated in bilayer-stabilized W1/O/W2 double emulsion: Effect of pectin as protective shell

In order to overcome the problem that traditional W1/O/W2 double emulsions do not have targeted release performance, thereby better meeting the health needs of consumers, ovalbumin fibrils/pectin-based bilayer-stabilized double emulsion (OP-BDE) co-encapsulated with Lactobacillus plantarum and curcumin was constructed with pectin as the outer protective shell, which was expected to be used in the development of novel functional foods. The effects of pectin coating on the viability of Lactobacillus plantarum under conditions including storage, pasteurization, freeze-thaw cycles and in vitro simulated digestion were investigated. Results showed that pectin as protective shell could significantly enhance the tolerance of Lactobacillus plantarum to various environmental factors. Besides, the adsorption of pectin endowed OP-BDE with higher lipolysis and stronger protective effect on curcumin, remarkably improving the photostability and bioaccessibility of curcumin. In addition, in vitro simulated gastrointestinal release study indicated that OP-BDE possessed programmed sequential release property, allowing curcumin and Lactobacillus plantarum to be released in small intestine and colon, respectively. OP-BDE is the first reported co-delivery emulsion system with programmed release characteristic. This study provides new insights into OP-BDE in constructing co-delivery systems and programmed sequential release of active substances, and has potential reference and application value in actual food production.

Nanoengineered Polymeric RNA Nanoparticles for Controlled Biodistribution and Efficient Targeted Cancer Therapy

RNA nanotechnology, including rolling circle transcription (RCT), has gained increasing interest as a fascinating siRNA delivery nanoplatform for biostable and tumor-targetable RNA-based therapies. However, due to the lack of fine-tuning technologies for RNA nanostructures, the relationship between physicochemical properties and siRNA efficacy of polymeric siRNA nanoparticles (PRNs) with different sizes has not yet been fully elucidated. Herein, we scrutinized the effects of size/surface chemistry-tuned PRNs on the biological and physiological interactions with tumors. PRNs with adjusted size and surface properties were prepared using sequential engineering processes: RCT, condensation, and nanolayer deposition of functional biopolymers. Through the RCT process, nanoparticles of three sizes with a diameter of 50-200 nm were fabricated and terminated with three types of biopolymers: poly-l-lysine (PLL), poly-l-glutamate (PLG), and hyaluronic acid (HA) for different surface properties. Among the PRNs, HA-layered nanoparticles with a diameter of ∼200 nm exhibited the most effective systemic delivery, resulting in superior anticancer effects in an orthotopic breast tumor model due to the CD44 receptor targeting and optimized nanosized structure. Depending on the type of PRNs, the in vivo siRNA delivery with protein expression inhibition differed by up to approximately 20-fold. These findings indicate that the types of layered biopolymers and the PRNs size mediate efficient polymeric siRNA delivery to the targeted tumors, resulting in high RNAi-induced therapeutic efficacy. This RNA-nanotechnology-based size/surface editing can overcome the limitations of siRNA therapeutics and represents a potent built-in module method to design RNA therapeutics tailored for targeted cancer therapy.

Layer-by-Layer siRNA Particle Assemblies for Localized Delivery of siRNA to Epithelial Cells through Surface-Mediated Particle Uptake

Localized delivery of small interfering RNA (siRNA) is a promising approach for spatial control of cell responses at biomaterial interfaces. Layer-by-layer (LbL) assembly of siRNA with cationic polyelectrolytes has been used in film and nanoparticle vectors for transfection. Herein, we combine the ability of particles to efficiently deliver siRNA with the ability of film polyelectrolyte multilayers to act locally. LbL particles were prepared with alternating layers of poly(l-arginine) and siRNA and capped with hyaluronic acid. Negatively charged LbL particles were subsequently assembled on the poly(l-lysine)-functionalized substrate to form a LbL particle-decorated surface. Cells grown in contact with the particle-decorated surface were able to survive, internalize particles, and undergo gene silencing. This work shows that particle-decorated surfaces can be engineered by using electrostatic interactions and used to deliver therapeutic payloads for cell-instructive biointerfaces.

Designing siRNA/chitosan-methacrylate complex nanolipogel for prolonged gene silencing effects

Despite immense revolutionary therapeutics potential, sustaining release of active small interfering RNA (siRNA) remains an arduous challenge. The development of nanoparticles with siRNA sustained release capabilities provides an avenue to enhance the therapeutic efficacy of gene-based therapy. Herein, we present a new system based on the encapsulation of siRNA/chitosan-methacrylate (CMA) complexes into liposomes to form UV crosslinkable Nanolipogels (NLGs) with sustained siRNA-release properties in vitro. We demonstrated that the CMA nanogel in NLGs can enhance the encapsulation efficiency of siRNA and provide sustained release of siRNA up to 28 days. To understand the particle mechanism of cellular entry, multiple endocytic inhibitors have been used to investigate its endocytosis pathways. The study saw positively charged NLGs entering cells via multiple endocytosis pathways, facilitating endosomal escape and slowly releasing siRNA into the cytoplasm. Transfection experiments confirmed that the crosslinked NLG delivery system provides effective transfection and prolonged silencing effect up to 14 days in cell cultures. We expect that this sustained-release siRNA NLG platform would be of interest in both fundamental biological studies and in clinical applications to extend the use of siRNA-based therapies.

A design approach for layer-by-layer surface-mediated siRNA delivery

The ability to coat scaffolds and wound dressings with therapeutic short interfering RNA (siRNA) holds much potential for applications in wound healing, cancer treatment, and regenerative medicine. Layer-by-layer (LbL) technology is an effective method to formulate polyelectrolyte thin films for local delivery of siRNA; however, the formation and efficacy of LbL coatings as drug delivery systems are highly contingent on the assembly conditions. Here, we investigate the effects of LbL assembly parameters on film composition and consequent siRNA-mediated gene knockdown efficiency in vitro. Films comprising poly(β-amino ester) (PBAE) and siRNA were built on polyglactin 910 (Vicryl) sutures consisting of poly(10% L-lactide, 90% glycolide). A fractional factorial design was employed, varying the following LbL assembly conditions: pH, ionic strength, PBAE concentration, and siRNA concentration. Effects of these parameters on PBAE loading, siRNA loading, their respective weight ratios, and in vitro siRNA-mediated knockdown were elucidated. The parameter effects were leveraged to create a rationally designed set of solution conditions that was predicted to give effective siRNA-mediated knockdown, but not included in any of the original experimental conditions. This level of knockdown with our rationally designed loading conditions (47%) is comparable to previous formulations from our lab while being simpler in construction and requiring fewer film layers, which could save time and cost in manufacturing. This study highlights the importance of LbL solution conditions in the preparation of surface-mediated siRNA delivery systems and presents an adaptable methodology for extending these electrostatically-assembled coatings to the delivery of other therapeutic nucleic acids. STATEMENT OF SIGNIFICANCE: Short interfering RNA (siRNA) therapeutics are powerful tools to silence aberrant gene expression in the diseased state; however, the clinical utility of these therapies relies on effective controlled delivery approaches. Electrostatic self-assembly through the layer-by-layer (LbL) process enables direct siRNA release from surfaces, but this method is highly dependent upon the specific solution conditions used. Here, we use a fractional factorial design to illustrate how these assembly conditions impact composition of siRNA-eluting LbL thin films. We then elucidate how these properties mediate in vitro transfection efficacy. Ultimately, this work presents a significant step towards understanding how optimization of assembly conditions for surface-mediated LbL delivery can promote transfection efficacy while reducing the processing and material required.

Increasing Angiogenesis Factors in Hypoxic Diabetic Wound Conditions by siRNA Delivery: Additive Effect of LbL-Gold Nanocarriers and Desloratadine-Induced Lysosomal Escape

Impaired wound healing in people with diabetes has multifactorial causes, with insufficient neovascularization being one of the most important. Hypoxia-inducible factor-1 (HIF-1) plays a central role in the hypoxia-induced response by activating angiogenesis factors. As its activity is under precise regulatory control of prolyl-hydroxylase domain 2 (PHD-2), downregulation of PHD-2 by small interfering RNA (siRNA) could stabilize HIF-1α and, therefore, upregulate the expression of pro-angiogenic factors as well. Intracellular delivery of siRNA can be achieved with nanocarriers that must fulfill several requirements, including high stability, low toxicity, and high transfection efficiency. Here, we designed and compared the performance of layer-by-layer self-assembled siRNA-loaded gold nanoparticles with two different outer layers-Chitosan (AuNP@CS) and Poly L-arginine (AuNP@PLA). Although both formulations have exactly the same core, we find that a PLA outer layer improves the endosomal escape of siRNA, and therefore, transfection efficiency, after endocytic uptake in NIH-3T3 cells. Furthermore, we found that endosomal escape of AuNP@PLA could be improved further when cells were additionally treated with desloratadine, thus outperforming commercial reagents such as Lipofectamine® and jetPRIME®. AuNP@PLA in combination with desloratadine was proven to induce PHD-2 silencing in fibroblasts, allowing upregulation of pro-angiogenic pathways. This finding in an in vitro context constitutes a first step towards improving diabetic wound healing with siRNA therapy.

Protein corona precoating on redox-responsive chitosan-based nano-carriers for improving the therapeutic effect of nucleic acid drugs

Spontaneous formation of protein corona on chitosan-based nano-carriers is inevitable once they enter the blood, which is considered to be an important factor that weakens the delivery efficiency and therapeutic effect of nucleic acid drugs. For this, cyclic RGDyK peptide (cRGD) modified bovine serum albumin (BSA) was designed as a corona to precoat on redox-responsive chitosan-based nano-carriers (TsR NPs) before administration. The effects of the precoating corona on the pharmaceutical properties and delivery efficiency of the nano-carriers and the therapeutic effect of model siRNA (siVEGF) were investigated. The results showed that BSA-cRGD formed steady corona around TsR NPs, which enhanced targeting ability to cancer cells and reduced serum proteins adsorption. The Bc corona improved the stability and biocompatibility of TsR NPs, increased the intracellular uptake, facilitated the lysosomal escape and maintained their redox-sensitive responsiveness, resulting in enhanced gene silencing efficiency and anti-tumor proliferation effects both in vitro and in vivo.

Experimental models of glaucoma filtration surgery

Glaucoma filtration surgery plays an important role in achieving intraocular pressure (IOP) reduction in patients who have high IOP despite maximum medical therapy. Preclinical experimental models of glaucoma filtration surgery contribute a great deal to our knowledge of the wound healing processes that predispose to scarring and may lead to poor outcomes. However, this research needs to be interpreted in the light of the specific study design, animal model and methods used. We review the existing literature addressing various models of experimental glaucoma filtration surgery, discuss the considerations in assessing these models and describe future steps in evaluating potential therapeutics and bleb characteristics that could impact translational research in this field.

Layer-by-layer coated nanoliposomes for oral delivery of insulin

Crossing the intestinal epithelial cell barrier safely and reaching the blood with therapeutic levels of bioactive insulin have been the ultimate goal of oral insulin delivery. The optimum way to overcome the barrier lies in the design of an efficient high drug loading carrier, that can protect insulin from the harsh Gastrointestinal (GI) environment and enhance its uptake and transport by epithelial cells. In the present study, we developed a multi-layered insulin loading strategy on an anionic nanoliposome surface based on electrostatic interaction with chitosan. The layer-by-layer (LbL) coated nanoliposomes achieved high insulin loading (10.7% by weight) and offered superior protection with limited release in simulated gastric fluid (SGF) (about 6% in 1 h), simulated intestinal fluid (SIF) (2% in two weeks), and phosphate buffered saline (PBS) (5% in two weeks). Intracellular imaging revealed that the LbL coated liposomes were internalized and intracellularly trafficked towards the basolateral side of the Caco-2 monolayer. Transported insulin demonstrated retention of bioactivity while crossing the epithelial barrier in the glucose uptake study in 3T3 L1-MBX adipocytes. In rat studies, oral administration of the formulation resulted in rapid absorption with a peak in plasma insulin levels 0.5 h post oral gavaging. This technology thus serves as a promising platform for potential oral insulin applications.

Small interfering RNAs (siRNAs) based gene silencing strategies for the treatment of glaucoma: Recent advancements and future perspectives

RNA-interference-based mechanisms, especially the use of small interfering RNAs (siRNAs), have been under investigation for the treatment of several ailments and have shown promising results for ocular diseases including glaucoma. The eye, being a confined compartment, serves as a good target for the delivery of siRNAs. This review focuses on siRNA-based strategies for gene silencing to treat glaucoma. We have discussed the ocular structures and barriers to gene therapy (tear film, corneal, conjunctival, vitreous, and blood ocular barriers), methods of administration for ocular gene delivery (topical instillation, periocular, intracameral, intravitreal, subretinal, and suprachoroidal routes) and various viral and non-viral vectors in siRNA-based therapy for glaucoma. The components and mechanism of siRNA-based gene silencing have been mentioned briefly followed by the basic strategies and challenges faced during siRNA therapeutics development. We have emphasized different therapeutic targets for glaucoma which have been under research by scientists and the current siRNA-based drugs used in glaucoma treatment. We also mention briefly strategies for siRNA-based treatment after glaucoma surgery.

Hydroxyapatite Particles Induced Modulation of Collagen Expression and Secretion in Primary Human Dermal Fibroblasts

Background

Hydroxyapatite (HA) [Ca₅(PO4)₃(OH)] is a naturally occurring calcium phosphate which makes up 60–70% of the dry weight of human bones. Nano-scale HA particles are increasingly being used as carriers for controlled and targeted delivery of bioactive agents like drugs, proteins, and nucleic acids due to their high porosity, negative charge, and biodegradability.

Purpose

Although much effort has been devoted to understanding the delivery kinetics and effects of the payloads in such carriers, a thorough understanding of the influence of the carriers themselves is lacking.

Methods

HA particles (300 µg/mL) were administered to primary human dermal fibroblasts (HDFs). The uptake and intracellular localization of the particles were determined by flow cytometry, confocal imaging, and transmission electron microscopy (TEM). Immunological assays and PCR were performed to determine the levels of pro-inflammatory cytokines and collagens in cell lysates and media supernatant.

Results

The current study explores the effects of poly-dispersed HA particles on primary HDFs as a model system. The majority of the particles were determined to range between 150 and 200 nm in diameter. Upon exposure to HA suspensions, primary HDFs internalized the particles by endocytosis within 6 hours of exposure, showing maximum uptake at 72 hours following which the particles were exocytosed by 168 hours. This correlated to reduced secretion of various pro-inflammatory and pro-collagenic cytokines. Biochemical analysis further revealed a reduction in Type I collagen expression and secretion.

Conclusion

HA particles have an immune-modulatory effect on dermal fibroblasts and reduce collagen production, which may impact the integrity of the extracellular matrix (ECM). This study demonstrates the need to consider the secondary effects of particulate carriers like HA, beyond basic cytotoxicity, in the specific tissue environment where the intended function is to be realized.

Combined Chemisorption and Complexation Generate siRNA Nanocarriers with Biophysics Optimized for Efficient Gene Knockdown and Air-Blood Barrier Crossing

Current nucleic acid (NA) nanotherapeutic approaches face challenges because of shortcomings such as limited control on loading efficiency, complex formulation procedure involving purification steps, low load of NA cargo per nanoparticle, endosomal trapping, and hampered release inside the cell. When combined, these factors significantly limit the amount of biologically active NA delivered per cell in vitro, delivered dosages in vivo for a prolonged biological effect, and the upscalability potential, thereby warranting early consideration in the design and developmental phase. Here, we report a versatile nanotherapeutic platform, termed auropolyplexes, for improved and efficient delivery of small interfering RNA (siRNA). Semitelechelic, thiolated linear polyethylenimine (PEI) was chemisorbed onto gold nanoparticles to endow them with positive charge. A simple two-step complexation method offers tunable loading of siRNA at concentrations relevant for in vivo studies and the flexibility for inclusion of multiple functionalities without any purification steps. SiRNA was electrostatically complexed with these cationic gold nanoparticles and further condensed with polycation or polyethyleneglycol-polycation conjugates. The resulting auropolyplexes ensured complete complexation of siRNA into nanoparticles with a high load of ∼15,500 siRNA molecules/nanoparticle. After efficient internalization into the tumor cell, an 80% knockdown of the luciferase reporter gene was achieved. Auropolyplexes were applied intratracheally in Balb/c mice for pulmonary delivery, and their biodistribution were studied spatio-temporally and quantitatively by optical tomography. Auropolyplexes were well tolerated with ∼25% of the siRNA dose remaining in the lungs after 24 h. Importantly, siRNA was released from auropolyplexes in vivo and a fraction also crossed the air-blood barrier, which was then excreted via kidneys, whereas >97% of gold nanoparticles were retained in the lung. Linear PEI-based auropolyplexes offer a combination of successful endosomal escape and better biocompatibility profile in vivo. Taken together, combined chemisorption and complexation endow auropolyplexes with crucial biophysical attributes, enabling a versatile and upscalable nanogold-based platform for siRNA delivery in vitro and in vivo.

Hierarchical assembly of nanostructured coating for siRNA-based dual therapy of bone regeneration and revascularization

Advancing bone implant engineering offers the opportunity to overcome crucial medical challenges and improve clinical outcomes. Although the establishment of a functional vascular network is crucial for bone development, its regeneration inside bone tissue has only received limited attention to date. Herein, we utilize siRNA-decorated particles to engineer a hierarchical nanostructured coating on clinically used titanium implants for the synergistic regeneration of skeletal and vascular tissues. Specifically, an siRNA was designed to target the regulation of cathepsin K and conjugated on nanoparticles. The functionalized nanoparticles were assembled onto the bone implant to form a hierarchical nanostructured coating. By regulating mRNA transcription, the coating significantly promotes cell viability and growth factor release related to vascularization. Moreover, microchip-based experiments demonstrate that the nanostructured coating facilitates macrophage-induced synergy in up-regulation of at least seven bone and vascular growth factors. Ovariectomized rat and comprehensive beagle dog models highlight that this siRNA-integrated nanostructured coating possesses all the key traits of a clinically promising candidate to address the myriad of challenges associated with bone regeneration.

Biodegradable Nanocarriers Resembling Extracellular Vesicles Deliver Genetic Material with the Highest Efficiency to Various Cell Types

Efficient delivery of genetic material to primary cells remains challenging. Here, efficient transfer of genetic material is presented using synthetic biodegradable nanocarriers, resembling extracellular vesicles in their biomechanical properties. This is based on two main technological achievements: generation of soft biodegradable polyelectrolyte capsules in nanosize and efficient application of the nanocapsules for co-transfer of different RNAs to tumor cell lines and primary cells, including hematopoietic progenitor cells and primary T cells. Near to 100% efficiency is reached using only 2.5 × 10^-4 pmol of siRNA, and 1 × 10^-3 nmol of mRNA per cell, which is several magnitude orders below the amounts reported for any of methods published so far. The data show that biodegradable nanocapsules represent a universal and highly efficient biomimetic platform for the transfer of genetic material with the utmost potential to revolutionize gene transfer technology in vitro and in vivo.

Enhancing chemoradiation of colorectal cancer through targeted delivery of raltitrexed by hyaluronic acid coated nanoparticles

Combined modality therapy incorporating raltitrexed (RTX), a thymidylate synthase inhibitor, and radiation can lead to improved outcome for rectal cancer patients. To increase delivery and treatment efficacy, we formulated a hyaluronic acid (HA) coated nanoparticle encapsulating RTX (HARPs) through layer-by-layer assembly. These particles were determined to have a diameter of ∼115 nm, with a polydispersity index of 0.112 and a zeta potential of -22 mV. Cell uptake in CT26 cells determined through flow cytometry showed a ∼5-fold increase between untargeted and HA-coated particles. Through viability and DNA damage assays, we assessed the potency of the free RTX and HARPs, and found increased DNA damage in cells treated with the RTX-loaded nanoparticles administered concurrently with radiation. In vivo efficacy through tumor growth inhibition was investigated in a syngeneic murine colorectal cancer model. Nanoparticle treatment showed no acute toxicity in vivo, and all treatments showed survival benefits for their respective groups compared to controls. HARPs alone slowed tumor growth, although not significantly. Radiation alone and in combination with the HARPs showed significant growth delay. Notably, the combination treatment significantly hindered tumor progression relative to the HARPs highlighting the benefit of this multipronged treatment. These results provide a foundation for loading RTX in a nanoparticle formulation, and establish a combined radiation and drug dosing schedule to determine optimal tumor growth delay and subsequent treatment efficacy.

Co-delivery of RNAi and chemokine by polyarginine nanocapsules enables the modulation of myeloid-derived suppressor cells

Myeloid-Derived Suppressor Cells (MDSCs), immunosuppressive cells that promote tumor growth, represent an attractive target in cancer immunotherapy. However, the clinical success of this strategy is limited by the lack of efficient drug delivery vehicles targeting this cell compartment. The objective of this work was to develop a delivery carrier, multilayer polymer nanocapsules, with the capacity to co-encapsulate two types of immunomodulatory drugs, a chemokine and an RNAi sequence, aimed at reverting MDSC-mediated immunosuppression. The chemokine CCL2, intended to attract monocyte-macrophage MDSCs, was encapsulated within the L2 inverse micellar aqueous domains of the lipid core of these nanocapsules. On the other hand, two different RNAi sequences that modulate the CCAAT/enhancer-binding protein beta (C/EBPβ) pathway, shC/EBPβ and miR 142-3p, were successfully associated to their polymer shell. These RNAi sequences were covered by subsequent layers of polyarginine and hyaluronic acid, thereby creating multi-layered assemblies that protected them and facilitated their targeted delivery. The in vitro studies performed in primary MDSCs cultures showed the capacity of miR 142-3p-loaded nanocapsules to reduce the highly immunosuppressive monocyte-macrophage subset. Additionally, the encapsulation of CCL2 within the nanocapsules induced a potent monocyte-macrophage chemoattraction that could be used to direct the therapy to these cell subsets. Finally, in vitro and in vivo studies showed the capacity of shC/EBPβ-loaded nanocapsules to downregulate C/EBPβ levels in MDSCs and to reduce monocyte differentiation into tumor-associated macrophages in an MCA-203 fibrosarcoma mice model. In conclusion, the multilayer polymer nanocapsules described here are efficient vehicles for the co-delivery of proteins and RNA, and are potential candidates as nanomedicines for the modulation of MDSCs.

Development of Targeted siRNA Nanocomplexes to Prevent Fibrosis in Experimental Glaucoma Filtration Surgery

RNAi induced by double-stranded small interfering RNA (siRNA) molecules has attracted great attention as a naturally occurring approach to silence gene expression with high specificity. The myocardin-related transcription factor/serum response factor (MRTF/SRF) pathway is a master regulator of cytoskeletal gene expression and, thus, represents a promising target to prevent fibrosis. A major hurdle to implementing siRNA therapies is the method of delivery, and we have, thus, optimized lipid-peptide-siRNA (LPR) nanoparticles containing MRTF-B siRNAs as a targeted approach to prevent conjunctival fibrosis. We tested 15 LPR nanoparticle formulations with different lipid compositions, surface charges, and targeting or non-targeting peptides in human conjunctival fibroblasts. In vitro, the LPR formulation of the DOTMA/DOPE lipid with the targeting peptide Y (LYR) was the most efficient in MRTF-B gene silencing and non-cytotoxic compared to the non-targeting formulation. In vivo, subconjunctival administration of LYR nanoparticles containing MRTF-B siRNAs doubled bleb survival in a pre-clinical rabbit model of glaucoma filtration surgery. Furthermore, MRTF-B LYR nanoparticles reduced the MRTF-B mRNA by 29.6% in rabbit conjunctival tissues, which led to significantly decreased conjunctival scarring with no adverse side effects. LYR-mediated delivery of siRNA shows promising results to increase bleb survival and to prevent conjunctival fibrosis after glaucoma filtration surgery.

Design and in vitro release study of siRNA loaded Layer by Layer nanoparticles with sustained gene silencing effect

OBJECTIVES

Clinical translation of siRNA therapeutics has been severely limited due to the lack of stable and sustained siRNA delivery systems. Furthermore, when nanocarrier systems with siRNA are administered systemically to treat diseases, insufficient doses reach the target tissue. Here we report the successful development of a new nanocarrier system for the management of fibrosis.

METHODS

The new carrier has a hydroxyapatite core, with alternating layers of siRNA and a cationic peptide. The siRNA used here targets secreted protein acidic and rich in cysteine (SPARC), a key matricellular protein involved in the regulation of collagen fibrillogenesis and assembly. We have also used FRET studies to elucidate the fate of the particles inside cells, including the mechanistic details of layer-by-layer detachment.

RESULTS

In vitro studies using murine conjunctiva fibroblasts show sustained release over 2 weeks, and that such released siRNA sustained SPARC knockdown without affecting cell growth, and maintained siRNA presence in the cells for at least two weeks with a single-dose treatment. Release studies of siRNA from particles in vitro gave insight on how the particles delivered prolonged gene-silencing effects.

CONCLUSION

A single treatment of the layer-by-layer nanoparticle designed can achieve sustained gene silencing over 2 weeks. Localized delivery of stabilized siRNA with sustained-release capabilities opens the door for many other applications of siRNA-based gene regulation.

Targeted therapy for the post-operative conjunctiva: SPARC silencing reduces collagen deposition

BACKGROUND

To develop targeted antifibrotic therapy for glaucoma filtration surgery; this study determines the effectiveness of small interfering RNA (siRNA) to reduce in vivo secreted protein acidic and rich in cysteine (SPARC) expression using the mouse model of conjunctival scarring.

METHODS

Experimental surgery was performed as described for the mouse model of conjunctival scarring. Scrambled (siScram) or Sparc (siSparc) siRNAs, loaded on layer-by-layer (LbL) nanoparticles, were injected into the conjunctiva immediately after surgery. Expression of Sparc, Col1a1, Fn1 and Mmp14 was measured by real-time PCR and immunoblotting on days 7 and 14 postsurgery. Live imaging of the operated eyes was performed using slit lamp, anterior segment-optical coherence tomography and confocal microscopy. Tissue pathology was evaluated by histochemical and immunofluorescent analyses of operated conjunctival cryosections. Tissue apoptosis was quantitated by annexin V assay. RESULTS : siSparc, delivered via expanded LbL nanoparticles, significantly inhibited Sparc transcription in both day 7 (2.04-fold) and day 14 (1.39-fold) treated tissues. Sparc suppression on day 7 was associated with a significant reduction of Col1a1 (2.52-fold), Fn1 (2.89-fold) and Mmp14 (2.23-fold) mRNAs. At the protein level, both SPARC and collagen 1A1 (COL1A1) were significantly reduced at both time points with siSparc treatment. Nanoparticles were visualised within cell-like structures by confocal microscopy, while overt tissue response or apoptosis was not observed. CONCLUSIONS : SPARC targeted therapy effectively reduced both SPARC and collagen production in the operated mouse conjunctiva. This proof-of-concept study suggests that targeted treatment of fibrosis in glaucoma surgery is safe and feasible, with the potential to extend to a range of potential genes associated with fibrosis.

A multifunctional nanoparticle constructed with a detachable albumin outer shell and a redox-sensitive inner core for efficient siRNA delivery to hepatocellular carcinoma cells

Successful delivery of small interfering RNA (siRNA) into the cytoplasm of target cells relies on biocompatible and efficient vectors. In this study, a novel multifunctional core/shell nanoparticle [CS-SS-9R/BSA-c(RGDyK)] was developed to effectively deliver siVEGF to hepatocellular carcinoma cells (Bel-7402 cells). To improve the gene payload and transfection efficiency, a positively charged inner core (CS-SS-9R) was constructed by grafting nona-arginine (9R) onto chitosan (CS) using disulphide bonds. The negatively charged outer shell [BSA-c(RGDyK)] assembled on the surface of the inner core by electrostatic forces that shielded high cationic charges and provided improved targeting. The protein outer shell gradually detached from the inner core in the acidic lysosomal environment, leaving the cationic inner core exposed in order to escape from lysosomes. The nanoparticles were capable of delivering siVEGF into Bel-7402 cells via integrin receptor-mediated endocytosis. Successful lysosomal escape of the inner core and the rapid release of siVEGF into the cytoplasm resulted in a 78.9% decrease in VEGF expression and 81.2% inhibition of tumour cell proliferation. In conclusion, this nanoparticle is responsive to the intracellular environment and accurately delivered siRNA into the cytoplasm, providing a safe and highly efficient gene delivery strategy for cancer therapy.

Calcium-based biomaterials for diagnosis, treatment, and theranostics

Calcium-based biomaterials with good biosafety and bio-absorbability are promising for biomedical applications such as diagnosis, treatment, and theranostics.

Preliminary study on fabrication, characterization and synergistic anti-lung cancer effects of self-assembled micelles of covalently conjugated celastrol-polyethylene glycol-ginsenoside Rh2

The aim of this study was to develop an amphipathic polyethylene glycol (PEG) derivative that was bi-terminally modified with celastrol and ginsenoside Rh2 (Celastrol-PEG-G Rh2). Such derivative was capable of forming novel, celastrol-loaded polymeric micelles (CG-M) for endo/lysosomal delivery and thereby synergistic treatment of lung cancer. Celastrol-PEG-G Rh2 with a yield of 55.6% was first synthesized and characterized. Its critical micellar concentration was 1 × 10-5 M, determined by pyrene entrapment method. CG-M had a small particle size of 121.53 ± 2.35 nm, a narrow polydispersity index of 0.214 ± 0.001 and a moderately negative zeta potential of -23.14 ± 3.15 mV. Celastrol and G Rh2 were rapidly released from CG-M under acidic and enzymatic conditions, but slowly released in normal physiological environments. In cellular studies, the internalization of celastrol and G Rh2 by human non-small cell lung cancer (A549) cells treated with CG-M was 5.8-fold and 1.8-fold higher than that of non-micelle control. Combinational therapy of celastrol and G Rh2 using CG-M exhibited synergistic anticancer activities in cell apoptosis and proliferation assays via rapid drug release within endo/lysosomes. Most importantly, the celastrol in CG-M exhibited a long elimination half-life of 445.3 ± 43.5 min and an improved area under the curve of 645060.8 ± 63640.7 ng/mL/h, that were 1.03-fold and 2.44-fold greater than those of non-micelle control, respectively. These findings suggest that CG-M is a promising vector for precisely releasing anticancer drugs within the tumor cells, and thereby exerts an improved synergistic anti-lung cancer effect.

Targeting Transforming Growth Factor-β Signaling in Primary Open-Angle Glaucoma

Transforming growth factor-β (TGF-β) may play a role in the pathogenesis of primary open-angle glaucoma (POAG). Elevated levels of TGF-β are found in the aqueous humor and in reactive optic nerve astrocytes in patients with glaucoma. In POAG, aqueous humor outflow resistance at the trabecular meshwork (TM) leads to increased intraocular pressure and retinal ganglion cell death. It is hypothesized that TGF-β increases outflow resistance by altering extracellular matrix homeostasis and cell contractility in the TM through interactions with other proteins and signaling molecules. TGF-β may also be involved in damage to the optic nerve head. Current available therapies for POAG focus exclusively on lowering intraocular pressure without addressing extracellular matrix homeostasis processes in the TM. The purpose of this review is to discuss possible therapeutic strategies targeting TGF-β in the treatment of POAG. Herein, we describe the current understanding of the role of TGF-β in POAG pathophysiology, and examine ways TGF-β may be targeted at the levels of production, activation, downstream signaling, and homeostatic regulation.

The Implications and Future Perspectives of Nanomedicine for Cancer Stem Cell Targeted Therapies

Cancer stem cells (CSCs) are believed to exhibit distinctive self-renewal, proliferation, and differentiation capabilities, and thus play a significant role in various aspects of cancer. CSCs have significant impacts on the progression of tumors, drug resistance, recurrence and metastasis in different types of malignancies. Due to their primary role, most researchers have focused on developing anti-CSC therapeutic strategies, and tremendous efforts have been put to explore methods for selective eradication of these therapeutically resistant CSCs. In recent years, many reports have shown the use of CSCs-specific approaches such as ATP-binding cassette (ABC) transporters, blockade of self-renewal and survival of CSCs, CSCs surface markers targeted drugs delivery and eradication of the tumor microenvironment. Also, various therapeutic agents such as small molecule drugs, nucleic acids, and antibodies are said to destroy CSCs selectively. Targeted drug delivery holds the key to the success of most of the anti-CSCs based drugs/therapies. The convention CSCs-specific therapeutic agents, suffer from various problems. For instance, limited water solubility, small circulation time and inconsistent stability of conventional therapeutic agents have significantly limited their efficacy. Recent advancement in the drug delivery technology has demonstrated that specially designed nanocarrier-based drug delivery approaches (nanomedicine) can be useful in delivering sufficient amount of drug molecules even in the most interiors of CSCs niches and thus can overcome the limitations associated with the conventional free drug delivery methods. The nanomedicine has also been promising in designing effective therapeutic regime against pump-mediated drug resistance (ATP-driven) and reduces detrimental effects on normal stem cells. Here we focus on the biological processes regulating CSCs' drug resistance and various strategies developed so far to deal with them. We also review the various nanomedicine approaches developed so far to overcome these CSCs related issues and their future perspectives.

Engineering nanolayered particles for modular drug delivery

Layer-by-layer (LbL) based self-assembly of nanoparticles is an emerging and powerful method to develop multifunctional and tissue responsive nanomedicines for a broad range of diseases. This unique assembly technique is able to confer a high degree of modularity, versatility, and compositional heterogeneity to nanoparticles via the sequential deposition of alternately charged polyelectrolytes onto a colloidal template. LbL assembly can provide added functionality by directly incorporating a range of functional materials within the multilayers including nucleic acids, synthetic polymers, polypeptides, polysaccharides, and functional proteins. These materials can be used to generate hierarchically complex, heterogeneous thin films on an extensive range of both traditional and novel nanoscale colloidal templates, providing the opportunity to engineer highly precise systems capable of performing the numerous tasks required for systemic drug delivery. In this review, we will discuss the recent advancements towards the development of LbL nanoparticles for drug delivery and diagnostic applications, with a special emphasis on the incorporation of biostability, active targeting, desirable drug release kinetics, and combination therapies into LbL nanomaterials. In addition to these topics, we will touch upon the next steps for the translation of these systems towards the clinic.

Bioactive Natural Protein-Hydroxyapatite Nanocarriers for Optimizing Osteogenic Differentiation of Mesenchymal Stem Cells

Improving the controlled release of bioactive growth factors to regulate cell behavior and tissue regeneration remains a need in tissue engineering and regenerative medicine. Inorganic and polymeric nanoparticles have been extensively fabricated as bioactive biomaterials with enhanced biocompatibility and effective carriers of therapeutic agents, however, challenges remain such as the achievement of high loading capacity and sustained release, and the bioactivity preservation of growth factors. Here, a multilayered, silk coated hydroxyapatite (HA) nanocarrier with drug loading-release capacity superior to pure silk or HA nanoparticles was developed. Bone morphogenetic protein-2 (BMP-2) was bound to the silk coatings with a high binding efficiency of 99.6%, significantly higher than that in silk or the HA nanoparticles alone. The release of BMP-2 was sustained in vitro over a period of 21 days without burst release. Compared with BMP-2 loaded silk or HA particles, bone mesenchymal stem cells (BMSCs) showed improved proliferation and osteogenesis when cultured with the BMP-2 loaded composite nanocarriers. Therefore, these silk-HA composite nanoparticles present a useful approach to designing bioactive nanocarrier systems with enhanced functions for bone tissue regeneration needs.

Receptor-targeted liposome-peptide-siRNA nanoparticles represent an efficient delivery system for MRTF silencing in conjunctival fibrosis

There is increasing evidence that the Myocardin-related transcription factor/Serum response factor (MRTF/SRF) pathway plays a key role in fibroblast activation and that knocking down MRTF can lead to reduced scarring and fibrosis. Here, we have developed a receptor-targeted liposome-peptide-siRNA nanoparticle as a non-viral delivery system for MRTF-B siRNA in conjunctival fibrosis. Using 50 nM siRNA, the MRTF-B gene was efficiently silenced by 76% and 72% with LYR and LER nanoparticles, respectively. The silencing efficiency was low when non-targeting peptides or siRNA alone or liposome-siRNA alone were used. LYR and LER nanoparticles also showed higher silencing efficiency than PEGylated LYR-P and LER-P nanoparticles. The nanoparticles were not cytotoxic using different liposomes, targeting peptides, and 50 nM siRNA. Three-dimensional fibroblast-populated collagen matrices were also used as a functional assay to measure contraction in vitro, and showed that MRTF-B LYR nanoparticles completely blocked matrix contraction after a single transfection treatment. In conclusion, this is the first study to develop and show that receptor-targeted liposome-peptide-siRNA nanoparticles represent an efficient and safe non-viral siRNA delivery system that could be used to prevent fibrosis after glaucoma filtration surgery and other contractile scarring conditions in the eye.

Matricellular proteins in drug delivery: Therapeutic targets, active agents, and therapeutic localization

Extracellular matrix is composed of a complex array of molecules that together provide structural and functional support to cells. These properties are mainly mediated by the activity of collagenous and elastic fibers, proteoglycans, and proteins such as fibronectin and laminin. ECM composition is tissue-specific and could include matricellular proteins whose primary role is to modulate cell-matrix interactions. In adults, matricellular proteins are primarily expressed during injury, inflammation and disease. Particularly, they are closely associated with the progression and prognosis of cardiovascular and fibrotic diseases, and cancer. This review aims to provide an overview of the potential use of matricellular proteins in drug delivery including the generation of therapeutic agents based on the properties and structures of these proteins as well as their utility as biomarkers for specific diseases.

Delivery of therapeutics using nanocarriers for targeting cancer cells and cancer stem cells

Development of cancer resistance, cancer relapse and metastasis are attributed to the presence of cancer stem cells (CSCs). Eradication of this subpopulation has been shown to increase life expectancy of patients. Since the discovery of CSCs a decade ago, several strategies have been devised to specifically target them but with limited success. Nanocarriers have recently been employed to deliver anti-CSC therapeutics for reducing the population of CSCs at the tumor site with great success. This review discusses the different therapeutic strategies that have been employed using nanocarriers, their advantages, success in targeting CSCs and the challenges that are to be overcome. Exploiting this new modality of cancer treatment in the coming decade may improve outcomes profoundly with promise of effective treatment response and reducing relapse and metastasis.

Accelerating the Translation of Nanomaterials in Biomedicine

Due to their size and tailorable physicochemical properties, nanomaterials are an emerging class of structures utilized in biomedical applications. There are now many prominent examples of nanomaterials being used to improve human health, in areas ranging from imaging and diagnostics to therapeutics and regenerative medicine. An overview of these examples reveals several common areas of synergy and future challenges. This Nano Focus discusses the current status and future potential of promising nanomaterials and their translation from the laboratory to the clinic, by highlighting a handful of successful examples.

Polysaccharides for the Delivery of Antitumor Drugs

Among the several delivery materials available so far, polysaccharides represent very attractive molecules as they can undergo a wide range of chemical modifications, are biocompatible, biodegradable, and have low immunogenic properties. Thus, polysaccharides can contribute to significantly overcome the limitation in the use of many types of drugs, including anti-cancer drugs. The use of conventional anti-cancer drugs is hampered by their high toxicity, mostly depending on the indiscriminate targeting of both cancer and normal cells. Additionally, for nucleic acid based drugs (NABDs), an emerging class of drugs with potential anti-cancer value, the practical use is problematic. This mostly depends on their fast degradation in biological fluids and the difficulties to cross cell membranes. Thus, for both classes of drugs, the development of optimal delivery materials is crucial. Here we discuss the possibility of using different kinds of polysaccharides, such as chitosan, hyaluronic acid, dextran, and pullulan, as smart drug delivery materials. We first describe the main features of polysaccharides, then a general overview about the aspects ruling drug release mechanisms and the pharmacokinetic are reported. Finally, notable examples of polysaccharide-based delivery of conventional anti-cancer drugs and NABDs are reported. Whereas additional research is required, the promising results obtained so far, fully justify further efforts, both in terms of economic support and investigations in the field of polysaccharides as drug delivery materials.

Oligolayer-coated nanoparticles: impact of surface topography at the nanobio interface

Layer-by-layer coating of nanoparticles with a layer number in the single-digit range has gained increasing attention in the field of nanomedicinal research. However, the impact of using various polyelectrolytes on oligolayer formation and, more importantly, their influence on the interaction with the biological system has not often been considered in the past. Hence, we investigated the polyelectrolyte deposition profiles and resulting surface topographies of up to three polyelectrolyte layers on a flat gold sensor surface using three different polycations, namely, poly(ethylene imine) (PEI), poly(allylamine hydrochloride) (PAH), and poly(diallylammonium chloride) (PD), each in combination with poly(styrenesulfonate) (PSS). Surface plasmon resonance spectroscopy and atomic force microscopy revealed that the PEI/PSS pair in particular showed a so-called overshoot phenomenon, which is associated with partial polyelectrolyte desorption from the surface. This is also reflected by a significant increase in the surface roughness. Then, after having transferred the oligolayer assembly onto nanoparticles of ∼32 nm, we realized that quite similar surface topographies must have emerged on a curved gold surface. A major finding was that the extent of surface roughness contributes significantly to the fashion by which the oligolayer-coated nanoparticles interact with serum proteins and associate with cells. For example, for the PEI/PSS system, both the surface roughness and protein adsorption increased by a factor of ∼12 from the second to third coating layer and, at the same time, the cell association massively decreased to only one-third. Our study shows that surface roughness, along with other particle properties such as size, shape, zeta potential, and hydrophobicity, is another decisive factor for nanoparticles in a biological context, which has indeed been discussed previously but has not to date been investigated for oligolayers.

Chitosan/siRNA functionalized titanium surface via a layer-by-layer approach for in vitro sustained gene silencing and osteogenic promotion

Titanium surface modification is crucial to improving its bioactivity, mainly its bone binding ability in bone implant materials. In order to functionalize titanium with small interfering RNA (siRNA) for sustained gene silencing in nearby cells, the layer-by-layer (LbL) approach was applied using sodium hyaluronate and chitosan/siRNA (CS/siRNA) nanoparticles as polyanion and polycation, respectively, to build up the multilayered film on smooth titanium surfaces. The CS/siRNA nanoparticle characterization was analyzed first. Dynamic contact angle, atomic force microscopy, and scanning electron microscopy were used to monitor the layer accumulation. siRNA loaded in the film was quantitated and the release profile of film in phosphate-buffered saline was studied. In vitro knockdown effect and cytotoxicity evaluation of the film were investigated using H1299 human lung carcinoma cells expressing green fluorescent protein (GFP). The transfection of human osteoblast-like cell MG63 and H1299 were performed and the osteogenic differentiation of MG63 on LbL film was analyzed. The CS/siRNA nanoparticles exhibited nice size distribution. During formation of the film, the surface wettability, topography, and roughness were alternately changed, indicating successful adsorption of the individual layers. The scanning electron microscope images clearly demonstrated the hybrid structure between CS/siRNA nanoparticles and sodium hyaluronate polymer. The cumulated load of siRNA increased linearly with the bilayer number and, more importantly, a gradual release of the film allowed the siRNA to be maintained on the titanium surface over approximately 1 week. In vitro transfection revealed that the LbL film-associated siRNA could consistently suppress GFP expression in H1299 without showing significant cytotoxicity. The LbL film loading with osteogenic siRNA could dramatically increase the osteogenic differentiation in MG63. In conclusion, LbL technology can potentially modify titanium surfaces with specific gene-regulatory siRNAs to enhance biofunction.

Monoclonal antibody-targeted fluorescein-5-isothiocyanate-labeled biomimetic nanoapatites: a promising fluorescent probe for imaging applications

Multifunctional biomimetic nanoparticles (NPs) are acquiring increasing interest as carriers in medicine and basic research since they can efficiently combine labels for subsequent tracking, moieties for specific cell targeting, and bioactive molecules, e.g., drugs. In particular, because of their easy synthesis, low cost, good biocompatibility, high resorbability, easy surface functionalization, and pH-dependent solubility, nanocrystalline apatites are promising candidates as nanocarriers. This work describes the synthesis and characterization of bioinspired apatite nanoparticles to be used as fluorescent nanocarriers targeted against the Met/hepatocyte growth factor receptor, which is considered a tumor associated cell surface marker of many cancers. To this aim the nanoparticles have been labeled with Fluorescein-5-isothiocyanate (FITC) by simple isothermal adsorption, in the absence of organic, possibly toxic, molecules, and then functionalized with a monoclonal antibody (mAb) directed against such a receptor. Direct labeling of the nanoparticles allowed tracking the moieties with spatiotemporal resolution and thus following their interaction with cells, expressing or not the targeted receptor, as well as their fate in vitro. Cytofluorometry and confocal microscopy experiments showed that the functionalized nanocarriers, which emitted a strong fluorescent signal, were rapidly and specifically internalized in cells expressing the receptor. Indeed, we found that, once inside the cells expressing the receptor, mAb-functionalized FITC nanoparticles partially dissociated in their two components, with some mAbs being recycled to the cell surface and the FITC-labeled nanoparticles remaining in the cytosol. This work thus shows that FITC-labeled nanoapatites are very promising probes for targeted cell imaging applications.

Developing novel anti-fibrotic therapeutics to modulate post-surgical wound healing in glaucoma: big potential for small molecules

Ocular fibrosis leads to significant visual impairment and blindness in millions of people worldwide, and is one of the largest areas of unmet need in clinical ophthalmology. The antimetabolites, mitomycin C and 5-fluorouracil, are the current gold standards used primarily to prevent fibrosis after glaucoma surgery, but have potentially blinding complications like tissue damage, breakdown and infection. This review thus focuses on the development of new classes of small molecule therapeutics to prevent post-surgical fibrosis in the eye, especially in the context of glaucoma filtration surgery. We discuss recent advances and innovations in ophthalmic wound healing research, including antibodies, RNAi, gene therapy, nanoparticles, liposomes, dendrimers, proteoglycans and small molecule inhibitors. We also review the challenges involved in terms of drug delivery, duration of action and potential toxicity of new anti-fibrotic agents in the eye.

Bimodal tumor-targeting from microenvironment responsive hyaluronan layer-by-layer (LbL) nanoparticles

Active targeting of nanoscale drug carriers can improve tumor-specific delivery; however, cellular heterogeneity both within and among tumor sites is a fundamental barrier to their success. Here, we describe a tumor microenvironment-responsive layer-by-layer (LbL) polymer drug carrier that actively targets tumors based on two independent mechanisms: pH-dependent cellular uptake at hypoxic tumor pH and hyaluronan-directed targeting of cell-surface CD44 receptor, a well-characterized biomarker for breast and ovarian cancer stem cells. Hypoxic pH-induced structural reorganization of hyaluronan-LbL nanoparticles was a direct result of the nature of the LbL electrostatic complex, and led to targeted cellular delivery in vitro and in vivo, with effective tumor penetration and uptake. The nanoscale drug carriers selectively bound CD44 and diminished cancer cell migration in vitro, while co-localizing with the CD44 receptor in vivo. Multimodal targeting of LbL nanoparticles is a powerful strategy for tumor-specific cancer diagnostics and therapy that can be accomplished using a single bilayer of polyamine and hyaluronan that, when assembled, produce a dynamic and responsive cell-particle interface.

The use of pH-sensitive functional selenium nanoparticles shows enhanced in vivo VEGF-siRNA silencing and fluorescence imaging

The utility of small interfering RNAs (siRNAs) has shown great promise in treating a variety of diseases including many types of cancer. While their ability to silence a wide range of target genes underlies their effectiveness, the application of therapies remains hindered by a lack of an effective delivery system. In this study, we sought to develop an siRNA-delivery system for VEGF, a known signaling molecule involved in cancer, that consists of two selenium nanoparticles SeNPs and G2/PAH-Cit/SeNPs. A G2/PAH-Cit/SeNP is a pH-sensitive delivery system that is capable of enhancing siRNA loading, thus increasing siRNA release efficiency and subsequent target gene silencing both in vitro and in vivo. In vivo experiments using G2/PAH-Cit/SeNPs@siRNA led to significantly higher accumulation of siRNA within the tumor itself, VEGF gene silencing, and reduced angiogenesis in the tumor. Furthermore, the G2/PAH-Cit/SeNP delivery system not only enhanced anti-tumor effects on tumor-bearing nude mice as compared to SeNPs@siRNA, but also resulted in weak occurrence of lesions in major target organs. In sum, this study provides a new class of siRNA delivery system, thereby providing an alternative therapeutic route for cancer treatment.

Using real-time impedance-based assays to monitor the effects of fibroblast-derived media on the adhesion, proliferation, migration and invasion of colon cancer cells

Increasing our knowledge of the mechanisms regulating cell proliferation, migration and invasion are central to understanding tumour progression and metastasis. The local tumour microenvironment contributes to the transformed phenotype in cancer by providing specific environmental cues that alter the cells behaviour and promotes metastasis. Fibroblasts have a strong association with cancer and in recent times there has been some emphasis in designing novel therapeutic strategies that alter fibroblast behaviour in the tumour microenvironment. Fibroblasts produce growth factors, chemokines and many of the proteins laid down in the ECM (extracellular matrix) that promote angiogenesis, inflammation and tumour progression. In this study, we use a label-free RTCA (real-time cell analysis) platform (xCELLigence) to investigate how media derived from human fibroblasts alters cancer cell behaviour. We used a series of complimentary and novel experimental approaches to show HCT116 cells adhere, proliferate and migrate significantly faster in the presence of media from human fibroblasts. As well as this, we used the xCELLigence CIM-plates system to show that HCT116 cells invade matrigel layers aggressively when migrating towards media derived from human fibroblasts. These data strongly suggest that fibroblasts have the ability to increase the migratory and invasive properties of HCT116 cells. This is the first study that provides real-time data on fibroblast-mediated migration and invasion kinetics of colon cancer cells.

Magnetically guided survivin-siRNA delivery and simultaneous dual-modal imaging visualization based on Fe3O4@mTiO2nanospheres for breast cancer

Fe₃O₄@mTiO₂/FMN-PEI as a siRNA delivery system can transfect survivin-siRNA to induce apoptosis, along with magnetic targeting, MRI and optical imaging.