Silica nanoparticles and polyethyleneimine (PEI)-mediated functionalization: a new method of PEI covalent attachment for siRNA delivery applications

Halloysite nanotubes-based hybrid silica monolithic spin tip for hydrophilic solid-phase extraction of sulbactam, cefoperazone, and cefuroxime in whole blood

In this study, we proposed a novel method utilizing polyethyleneimine (PEI)-modified halloysite nanotubes (HNTs)-based hybrid silica monolithic spin tip to analyze hydrophilic β-lactam antibiotics and β-lactamases inhibitors in whole blood samples for the first time. HNTs were incorporated directly into the hybrid silica monolith via a sol-gel method, which improved the hydrophilicity of the matrix. The as-prepared monolith was further modified with PEI by glutaraldehyde coupling reaction. It was found that the PEI-modified HNTs-based hybrid silica monolith enabled a large adsorption capacity of cefoperazone at 35.7 mg g-1. The monolithic spin tip-based purification method greatly reduced the matrix effect of whole blood samples and had a detection limit as low as 0.1 - 0.2 ng mL-1. In addition, the spiked recoveries of sulbactam, cefuroxime, and cefoperazone in blank whole blood were in the range of 89.3-105.4 % for intra-day and 90.6-103.5 % for inter-day, with low relative standard deviations of 1.3-7.2 % and 4.9-10.5 %, respectively. This study introduces a new strategy for preparing nanoparticles incorporated in a hybrid silica monolith with a high adsorption capacity. Moreover, it offers a valuable tool to monitor sulbactam, cefoperazone, and cefuroxime in whole blood from pregnant women with the final aim of guiding their administration.

Development of light and pH-dual responsive self-quenching theranostic SPION to make EGFR overexpressing micro tumors glow and destroy

Drug resistant and undetectable tumors easily escape treatment leading metastases and/or recurrence of the lethal disease. Therefore, it is vital to diagnose and destroy micro tumors using simple yet novel approaches. Here, we present fluorescence-based detection and light-based destruction of cancer cells that are known to be resistant to standard therapies. We developed a superparamagnetic iron oxide nanoparticle (SPION)-based theranostic agent that is composed of self-quenching light activated photosensitizer (BPD) and EGFR targeting ligand (Anti-EGFR ScFv or GE11 peptide). Photosensitizer (BPD) was immobilized to PEG-PEI modified SPION with acid-labile linker. Prior to stimulation of the theranostic system by light its accumulation within cancer cells is vital since BPD phototoxicity and fluorescence is activated by lysosomal proteolysis. As BPD is cleaved, the system switches from off to on position which triggers imaging and therapy. Targeting, therapeutic and diagnostic features of the theranostic system were evaluated in high and moderate level EGFR expressing pancreatic cancer cell lines. Our results indicate that the system distinguishes high and moderate EGFR expression levels and yields up to 4.3-fold increase in intracellular fluorescence intensity. Amplification of fluorescence signal was as low as 1.3-fold in the moderate or no EGFR expressing cell lines. Anti-EGFR ScFv targeted SPION caused nearly 2-fold higher cell death via apoptosis in high EGFR expressing Panc-1 cell line. The developed system, possessing advanced targeting, enhanced imaging and effective therapeutic features, is a promising candidate for multi-mode detection and destruction of residual drug-resistant cancer cells.

Multiepitope glycan based laser assisted fluorescent nanocomposite with dual functionality for sensing and ablation of Pseudomonas aeruginosa

Pseudomonas aeruginosa (P. aeruginosa) infection is becoming a severe health hazard and needs early diagnosis with high specificity. However, the non-specific binding of a biosensor is a challenge to the current bacterial detection system. For the first time, we chemically synthesized a galactose tripod (GT) as a P. aeruginosa-specific ligand. We conjugated GT to a photothermally active fluorescent nanocomposite (Au@SiO2-TCPP). P. aeruginosa can be detected using Au@SiO2-TCPP-GT, and additionally ablated as well using synergistic photothermal and photodynamic therapy. Molecular dynamics and simulation studies suggested better binding of GT (binding energy = -6.6 kcal mol-1) with P. aeruginosa lectin than that of galactose monopod (GM) (binding energy = -5.9 kcal mol-1). Furthermore, a binding study was extended to target P. aeruginosa, which has a galactose-binding carbohydrate recognition domain receptor. The colorimetric assay confirmed a limit of detection (LOD) of 104 CFU mL-1. We also looked into the photosensitizing property of Au@SiO2-TCPP-GT, which is stimulated by laser light (630 nm) and causes photoablation of bacteria by the formation of singlet oxygen in the surrounding media. The cytocompatibility of Au@SiO2-TCPP-GT was confirmed using cytotoxicity assays on mammalian cell lines. Moreover, Au@SiO2-TCPP-GT also showed non-hemolytic activity. Considering the toxicity analysis and efficacy of the synthesized glycan nanocomposites, these can be utilized for the treatment of P. aeruginosa-infected wounds. Furthermore, the current glycan nanocomposites can be used for bacterial detection and ablation of P. aeruginosa in contaminated food and water samples as well.

Nanobiotechnological approaches in osteosarcoma therapy: Versatile (nano)platforms for theranostic applications

Constructive achievements in the field of nanobiotechnology and their translation into clinical course have led to increasing attention towards evaluation of their use for treatment of diseases, especially cancer. Osteosarcoma (OS) is one of the primary bone malignancies that affects both males and females in childhood and adolescence. Like other types of cancers, genetic and epigenetic mutations account for OS progression and several conventional therapies including chemotherapy and surgery are employed. However, survival rate of OS patients remains low and new therapies in this field are limited. The purpose of the current review is to provide a summary of nanostructures used in OS treatment. Drug and gene delivery by nanoplatforms have resulted in an accumulation of therapeutic agents for tumor cell suppression. Furthermore, co-delivery of genes and drugs by nanostructures are utilized in OS suppression to boost immunotherapy. Since tumor cells have distinct features such as acidic pH, stimuli-responsive nanoparticles have been developed to appropriately target OS. Besides, nanoplatforms can be used for biosensing and providing phototherapy to suppress OS. Furthermore, surface modification of nanoparticles with ligands can increase their specificity and selectivity towards OS cells. Clinical translation of current findings suggests that nanoplatforms have been effective in retarding tumor growth and improving survival of OS patients.

Grafting of Poly(ethylene imine) to Silica Nanoparticles for Odor Removal from Recycled Materials

One of the major obstacles to the reuse of recycled plastic materials is the emanation of after-process odors from recycled polymers and composites. Typically, recycled polymers are blended with an off-odor adsorbent additive in the recycling chain to eliminate these smells. This article describes an innovative ultrasonically assisted method of grafting poly(ethylene imine) (PEI) to silica nanoparticles (SiO₂) initiated by benzoyl peroxide (BP) which acts as an odor remover. To prepare the PEI/Si, the branched PEI was grafted onto the silica surface without a coupling agent. This made the grafting process straightforward, easy and low in cost. Fourier Transform Infrared (FTIR) analysis confirmed the successful grafting of PEI to silica. The thermogravimetric analysis (TGA) indicated the formation of two different fractions: a polymeric fraction covalently attached to the nanoparticle surface and a non-grafted PEI fraction that was removed during extraction. Up to 30% of the grafted-PEI fractions were produced at the lowest BP concentration with the highest PEI molecular weight at silica-to-PEI weight ratios of (1:1) to (3:1). The sensory assessment showed a substantial reduction in overall odor intensity for 30% of the recycled plastic-containing materials and a ~75% reduction in volatile organic compounds (VOCs) for 100% of the recycled plastics. These results strongly suggest that this innovative PEI/Si nanocomposite can be successfully commercialized for odor removal. To the authors’ best knowledge, this is the first reported work describing a one-pot reaction for grafting PEI to different nanoparticle surfaces.

Imaging Intracellular Drug/siRNA Co-Delivery by Self-Assembly Cross-Linked Polyethylenimine with Fluorescent Core-Shell Silica Nanoparticles

Multifunctional theranostic nanomaterial represents one type of emerging agent with the potential to offer both sensitive diagnosis and effective therapy. Herein, we report a novel drug/siRNA co-delivery nanocarrier, which is based on fluorescent mesoporous core-shell silica nanoparticles coated by cross-linked polyethylenimine. The fluorescent mesoporous core-shell silica nanoparticles can provide numerous pores for drug loading and negative charged surface to assemble cross-linked polyethylenimine via electrostatic interaction. Disulfide cross-linked polyethylenimine can be absorbed on the surface of silica nanoparticles which provide the feasibility to bind with negatively charged siRNA and release drug "on-demand". In addition, the hybrid nanoparticles can be easily internalized into cells to realize drug/siRNA co-delivery and therapeutic effect imaging. This work would stimulate interest in the use of self-assembled cross-linked polyethylenimine with fluorescent mesoporous core-shell silica nanoparticles to construct multifunctional nanocomposites for tumor therapy.

Stability of Boron Nitride Nanosphere Dispersions in the Presence of Polyelectrolytes

Boron nitride nanospheres (BNNSs) were functionalized with polyelectrolytes. The effect of the polyelectrolyte dose and ionic strength on the charging and aggregation properties was investigated. At appropriate polyelectrolyte doses, charge neutralization occurred, whereas by increasing the dose, charge reversal was observed. The complete coating of the particles was indicated by a plateau in the ζ-potential values, which do not change significantly beyond the dose corresponding to the onset of such a plateau. The dispersions were highly aggregated around the charge neutralization point, while at lower or higher doses, the particles were stable. The salt-induced aggregation experiments revealed that the polyelectrolyte coatings contribute to the colloidal stability of the particles, namely, the critical coagulation concentrations deviated from the one determined for bare BNNSs. The presence of electrostatic and steric interparticle forces induced by the adsorbed polyelectrolyte chains was assumed. The obtained results confirm that the comprehensive investigation of the colloidal stability of BNNS particles is crucial to design stable or unstable dispersions and that polyelectrolytes are suitable agents for both stabilization and destabilization of BNNS dispersions, depending on the purpose of their application.

Efficient Heat Shielding of Steel with Multilayer Nanocomposite Thin Film

In an effort to protect metal substrates from extreme heat, polymer-clay multilayer thin films are studied as expendable thermal barrier coatings. Nanocomposite films with a thickness ranging from 2 to 35 μm were deposited on steel plates and exposed to the flame from a butane torch. The 35 μm coating, composed of 14 deposited bilayers of tris(hydroxymethyl)aminomethane (THAM)-buffered polyethylenimine (PEI) and vermiculite clay (VMT), decreased the maximum temperature observed on the back side of a 0.32 cm thick steel plate by over 100 °C when heated with a butane torch. Upon exposure to high temperature, the polymer and amine salt undergo pyrolysis and intumesce, subsequently forming a char and blowing gas. The char encases the nanoclay platelets, and a ceramic bubble is formed. The macro-scale bubble, in tandem with the nanocomposite coating properties, increases resistance to heat transfer into the underlying metal substrate. This heat shielding behavior occurs through radiative effects and low aggregate through-plane conductivity resulting from multilayer nanodomains and intumesced porosity (i.e., conduction through the gas as the film expands to form a ceramic bubble). These relatively thin and lightweight films could be used to protect important metal parts (in automobiles, aircraft, etc.) from fire-related damage or other types of transient high-temperature situations.

Fabrication and Optimization of Linear PEI-Modified Crystal Nanocellulose as an Efficient Non-Viral Vector for In-Vitro Gene Delivery

BACKGROUND

One of the major challenges in gene therapy is producing gene carriers that possess high transfection efficiency and low cytotoxicity (1). To achieve this purpose, crystal nanocellulose (CNC) -based nanoparticles grafted with polyethylenimine (PEI) have been developed as an alternative to traditional viral vectors to eliminate potential toxicity and immunogenicity.

METHODS

In this study, CNC-PEI10kDa (CNCP) nanoparticles were synthetized and their transfection efficiency was evaluated and compared with linear cationic PEI10kDa (PEI) polymer in HEK293T (HEK) cells. Synthetized nanoparticles were characterized with AFM, FTIR, DLS, and gel retardation assays. In-vitro gene delivery efficiency by nano-complexes and their effects on cell viability were determined with fluorescent microscopy and flow cytometry.

RESULTS

Prepared CNC was oxidized with sodium periodate and its surface cationized with linear PEI. The new CNCP nano-complex showed different transfection efficiencies at different nanoparticle/plasmid ratios, which were greater than those of PEI polymer. CNPC and Lipofectamine were similar in their transfection efficiencies and effect on cell viability after transfection.

CONCLUSION

CNCP nanoparticles are appropriate candidates for gene delivery. This result highlights CNC as an attractive biomaterial and demonstrates how its different cationized forms may be applied in designing gene delivery systems.

Effect of Confinement in Nanopores on RNA Interactions with Functionalized Mesoporous Silica Nanoparticles

Amine-functionalized mesoporous silica nanoparticles (MSNPAs) are ideal carriers for oligonucleotides for gene delivery and RNA interference. This investigation examines the thermodynamic driving force of interactions of double-stranded (ds) RNA with MSNPAs as a function of RNA length (84 and 282 base pair) and particle pore diameter (nonporous, 2.7, 4.3, and 8.1 nm) using isothermal titration calorimetry, extending knowledge of solution-based nucleic acid-polycation interactions to RNA confined in nanopores. Adsorption of RNA follows a two-step process: endothermic interactions driven by entropic contribution from counterion (and water) release and an exothermic regime dominated by short-range interactions within the pores. Evidence of hindered pore loading of the longer RNA and pore size-dependent confinement of RNA in the MSPAs is provided from the relative contributions of the endothermic and exothermic regimes. Reduction of endothermic and exothermic enthalpies in both regimes in the presence of salt for both lengths of RNA indicates the significant contribution of short-range electrostatic interactions, whereas ΔH and ΔG values are consistent with conformation changes and desolvation of nucleic acids upon binding with polycations. Knowledge of the interactions between RNA and functionalized porous nanoparticles will aid in porous nanocarrier design suitable for functional RNA delivery.

Polymer-modified mesoporous silica microcubes (P@MSMCs) for the synergistic oxidative entrapment of Ag(i), Ti(iv), and Zn(ii) from natural river water

Herein, we demonstrate a hydrothermal route to the one-pot synthesis of polymeric mesoporous silica microcubes (P@MSMCs) for the adsorption of heavy metal ions. During the synthesis of P@MSMCs from column silica gel, the roles and combination of the polymer and an etchant were characterized. Moreover, the porosity of P@MSMCs was tailored by adjusting the reaction temperature between 75 °C and 200 °C. The characterization through UV, FTIR, FESEM, XRD, BET, and EDX techniques exhibited that P@MSMCs have a well-ordered mesoporous structure with cubic morphology. The P@MSMCs had a diameter of 2 μm, with an average pore volume and pore size of 0.69 cm3 g-1 and 10.08 nm, respectively. The results indicated that the P@MSMCs have excellent adsorption capacity for Ag(i), Ti(iv), and Zn(ii) due to the formation of an aggregated complex. These aggregations led to affordable density difference-based separation of these metal ions through centrifugation, filtration or simple decantation. The removal efficiencies for Ag(i), Ti(iv), and Zn(ii) were observed to be 520, 720, and 850 mg g-1, respectively. The kinetic studies demonstrated that the adsorption performance fitted well to the pseudo-second-order kinetic model. The as-synthesized P@MSMCs were stable in the wide pH range of 4-8. Significantly, the recycling or reuse results displayed effective adsorption performance of these P@MSMCs for up to 5 cycles. The adsorption results obtained herein will promote the development of similar strategies for the removal of heavy metal ions from natural water.

Lipid-based Vehicles for siRNA Delivery in Biomedical Field

BACKGROUND

Genetic drugs have aroused much attention in the past twenty years. RNA interference (RNAi) offers novel insights into discovering potential gene functions and therapies targeting genetic diseases. Small interference RNA (siRNA), typically 21-23 nucleotides in length, can specifically degrade complementary mRNA. However, targeted delivery and controlled release of siRNA remain a great challenge.

METHODS

Different types of lipid-based delivery vehicles have been synthesized, such as liposomes, lipidoids, micelles, lipoplexes and lipid nanoparticles. These carriers commonly have a core-shell structure. For active targeting, ligands may be conjugated to the surface of lipid particles.

RESULTS

Lipid-based drug delivery vehicles can be utilized in anti-viral or anti-tumor therapies. They can also be used to tackle genetic diseases or discover novel druggable genes.

CONCLUSION

In this review, the structures of lipid-based vehicles and possible surface modifications are described, and applications of delivery vehicles in biomedical field are discussed.

Continuous Multistage Synthesis and Functionalization of Sub-100 nm Silica Nanoparticles in 3D-Printed Continuous Stirred-Tank Reactor Cascades

The controlled and continuous production of nanoparticles (NPs) with functionalized surfaces remains a technological challenge. We present a multistage synthetic platform, consisting of 3D-printed miniature continuous stirred-tank reactor (CSTR) cascades, for the continuous synthesis and functionalization of SiO₂ NPs. The use of the CSTR platform provides ideal and rapid mixing of precursor solutions, precise injection of additional reagents for multistep reactions, and facile operation when using viscous solutions and handling of syntheses with longer reaction times. To exemplify the use of such custom-designed CSTR cascades, amine- and carbohydrate-functionalized SiO₂ NPs are chosen as model reaction systems. In particular, the intensified flow reactor units allowed for the reproducible formation of SiO₂ NPs with diameters less than 100 nm and narrow size distributions (3-8%). Most importantly, by assembling various 3D-printed CSTR cascades, we synthesized gluconolactone-capped polyethylenimine-modified silica NPs in a fully continuous manner. The inherent control over NP surface charge, reactor scalability, and the significant shortening of processing times (less than 10 min) compared to batch methodologies (several days) strongly indicate the ability of the reactor technology to accelerate continuous nanomanufacturing. In general, it provides a simple route for the reproducible preparation of functionalized NPs, thus expanding the gamut of flow reactors for material synthesis.

pSBMA-Conjugated Magnetic Nanoparticles for Selective IgG Separation

Two types of zwitterionic polymer-modified magnetic nanoparticles (NPs) are fabricated by conjugating pSBMA onto PEI-precoated NPs via either a one-step method (1S NPs) or two-step method (2S NPs). For both methods, divinyl sulfone is used as the linker molecule. Although 1S NPs were capable of resisting both IgG and BSA, 2S NPs exhibited specificity toward IgG adsorption in complex biological fluids, e.g., in a mixture of serums and IgG. The moderate interactions ( K_d ≈ 1.2 μM) between IgG and 2S NPs are 3 orders of magnitude lower than IgG binding with protein A ( K_d 10 nM). Through complementary characterizations and analyses, we rationalize that the surface developed herein with IgG specificity contains two key components: polyzwitterions with a short chain length and sulfone groups with a high density.

Microwave induced synthesis of ZnO nanorods and their efficacy as a drug carrier with profound anticancer and antibacterial properties

In the present study, we report the microwave-induced synthesis of fluorescent zinc oxide nanorods (ZnO) and their usage as a cargo material to carry hydrophobic drug, quercetin. TEM and SEM showed the rod-shape morphology of our synthesized ZnO. XRD showed several diffraction peaks correspond to a hexagonal wurtzite structure. The optical and chemical natures of these nanorods were also confirmed from the UV-vis (showed a distinct absorption bands from 361 to 395 nm) and FTIR spectrum (showed absorption band specific to Zn-O stretching). The synthesized ZnO also showed fluorescence emission at around 550 nm when excited under UV irradiation. Quercetin was loaded onto ZnO surface via employing a metal ion-ligand coordination bond, (ZnO/QR), which exhibit pH-sensitive release behavior. ZnO/QR displayed superior drug loading content (42%) and loading efficiency (72.4%). in vitro assays showed that ZnO/QR exhibited higher anticancer, as well as antibacterial activities compared with free quercetin and ZnO. All these results highlight the synthesis of ZnO nanorods under microwave irradiation, which can be used as a plausible therapeutic option for bioimaging and drug delivery purpose.

AKT2 siRNA delivery with amphiphilic-based polymeric micelles show efficacy against cancer stem cells

Development of RNA interference-based therapies with appropriate therapeutic window remains a challenge for advanced cancers. Because cancer stem cells (CSC) are responsible of sustaining the metastatic spread of the disease to distal organs and the progressive gain of resistance of advanced cancers, new anticancer therapies should be validated specifically for this subpopulation of cells. A new amphihilic-based gene delivery system that combines Pluronic^® F127 micelles with polyplexes spontaneously formed by electrostatic interaction between anionic siRNA and cationic polyethylenimine (PEI) 10K, was designed (PM). Resultant PM gather the requirements for an efficient and safe transport of siRNA in terms of its physicochemical characteristics, internalization capacity, toxicity profile and silencing efficacy. PM were loaded with a siRNA against AKT2, an important oncogene involved in breast cancer tumorigenesis, with a special role in CSC malignancy. Efficacy of siAKT2-PM was validated in CSC isolated from two breast cancer cell lines: MCF-7 and Triple Negative MDA-MB-231 corresponding to an aggressive subtype of breast cancer. In both cases, we observed significant reduction on cell invasion capacity and strong inhibition of mammosphere formation after treatment. These results prompt AKT2 inhibition as a powerful therapeutic target against CSC and pave the way to the appearance of more effective nanomedicine-based gene therapies aimed to prevent CSC-related tumor recurrence.

Lyophilization and stability of antibody-conjugated mesoporous silica nanoparticle with cationic polymer and PEG for siRNA delivery

Introduction

Long-term stability of therapeutic candidates is necessary toward their clinical applications. For most nanoparticle systems formulated in aqueous solutions, lyophilization or freeze-drying is a common method to ensure long-term stability. While lyophilization of lipid, polymeric, or inorganic nanoparticles have been studied, little has been reported on lyophilization and stability of hybrid nanoparticle systems, consisting of polymers, inorganic particles, and antibody. Lyophilization of complex nanoparticle systems can be challenging with respect to preserving physicochemical properties and the biological activities of the materials. We recently reported an effective small-interfering RNA (siRNA) nanoparticle carrier consisting of 50-nm mesoporous silica nanoparticles decorated with a copolymer of polyethylenimine and polyethyleneglycol, and antibody.

Materials and methods

Toward future personalized medicine, the nanoparticle carriers were lyophilized alone and loaded with siRNA upon reconstitution by a few minutes of simple mixing in phosphate-buffered saline. Herein, we optimize the lyophilization of the nanoparticles in terms of buffers, lyoprotectants, reconstitution, and time and temperature of freezing and drying steps, and monitor the physical and chemical properties (reconstitution, hydrodynamic size, charge, and siRNA loading) and biological activities (gene silencing, cancer cell killing) of the materials after storing at various temperatures and times.

Results

The material was best formulated in Tris-HCl buffer with 5% w/w trehalose. Freezing step was performed at −55°C for 3 h, followed by a primary drying step at −40°C (100 µBar) for 24 h and a secondary drying step at 20°C (20 µBar) for 12 h. The lyophilized material can be stored stably for 2 months at 4°C and at least 6 months at −20°C.

Conclusion

We successfully developed the lyophilization process that should be applicable to other similar nanoparticle systems consisting of inorganic nanoparticle cores modified with cationic polymers, PEG, and antibodies.

Poly (amidoamine) (PAMAM) dendrimer mediated delivery of drug and pDNA/siRNA for cancer therapy

Poly (amidoamine) (PAMAM) dendrimers are well-defined, highly branched macromolecules with numerous active amine groups on the surface. Because of their unique properties, PAMAM dendrimers have steadily grown in popularity in drug delivery, gene therapy, medical imaging and diagnostic application. This review focuses on the recent developments on the application in PAMAM dendrimers as effective carriers for drug and gene (pDNA, siRNA) delivery in cancer therapy, including: a) PAMAM for anticancer drug delivery; b) PAMAM and gene therapy; c) PAMAM used in overcoming tumor multidrug resistance; d) PAMAM used for hybrid nanoparticles; and e) PAMAM linked or loaded in other nanoparticles.

Multifunctional targeting vinorelbine plus tetrandrine liposomes for treating brain glioma along with eliminating glioma stem cells

Malignant brain glioma is the most lethal and aggressive type of cancer. Surgery and radiotherapy cannot eliminate all glioma stem cells (GSCs) and blood–brain barrier (BBB) restricts the movement of antitumor drugs from blood to brain, thus leading to the poor prognosis with high recurrence rate. In the present study, the targeting conjugates of cholesterol polyethylene glycol polyethylenimine (CHOL-PEG₂₀₀₀-PEI) and D-a-tocopheryl polyethylene glycol 1000 succinate vapreotide (TPGS₁₀₀₀-VAP) were newly synthesized for transporting drugs across the BBB and targeting glioma cells and GSCs. The multifunctional targeting vinorelbine plus tetrandrine liposomes were constructed by modifying the targeting conjugates. The studies were undertaken on BBB model, glioma cells, GSCs, and glioma-bearing mice. In vitro results showed that multifunctional targeting drugs-loaded liposomes with suitable physicochemical property could enhance the transport drugs across the BBB, increase the intracellular uptake, inhibit glioma cells and GSCs, penetrate and destruct the GSCs spheroids, and induce apoptosis via activating related apoptotic proteins. In vivo results demonstrated that multifunctional targeting drugs-loaded liposomes could significantly accumulate into brain tumor location, show the specificity to tumor sites, and result in a robust overall antitumor efficacy in glioma-bearing mice. These data suggested that the multifunctional targeting vinorelbine plus tetrandrine liposomes could offer a promising strategy for treating brain glioma.

In Situ Healing of Compromised Membranes via Polyethylenimine-Functionalized Silica Microparticles

Microscale damages to membranes used in large-scale filtration processes for water treatment can result in severe degradation of product water quality. One promising technology to address this issue is in situ healing of compromised membranes via healing agents that are added to the feed side of a membrane system and seal the defect site because of increased hydraulic drag through damage site during filtration. We herein introduce an improved in situ membrane healing method using amine-functionalized silica microparticles that is effective under varying operating conditions, overcoming limitations faced by previous healing agents such as chitosan agglomerates. The silica microparticles are functionalized with branched polyethylenimine (PEI) molecules for efficient interparticle cross-linking with glutaraldehyde. The PEI-decorated silica microparticles (SiO₂@PEI MPs) were characterized using scanning electron microscopy, dynamic light scattering, and zeta potential analysis. This study investigates the selective deposition of the SiO₂@PEI MPs on the damage area using confocal laser scanning microscopy under variable cross-flow rate (0.5-2.0 L/min) and flushing time (10 to 30 min) conditions. The in situ healing technique recovered the particle rejection of compromised membranes to 99.1% of the original membrane's performance without any flux decline. The results of this study show that the use of SiO₂@PEI MPs is a promising and practical approach to ensure membrane process integrity.

The Serum-Resistant Transfection Evaluation and Long-Term Stability of Gene Delivery Dry Powder Based on Mesoporous Silica Nanoparticles and Polyethyleneimine by Freezing-Drying

Mesoporous silica nanoparticles (MSNs) with large surface area, tunable pore size, and low toxicity can act as suitable vehicles for drug and gene delivery. An MSN/DNA/PEI complex delivery system was prepared by using MSNs to hold plasmid DNA coated with polyethyleneimine (PEI), and the dry powder formulation was produced by freeze-drying with trehalose as lyoprotectant. The MSN/DNA/PEI complexes successfully enhanced the gene expression with about 1.5-fold higher efficiency as compared with the control, and even better effects and lower toxicity were achieved at lower content of PEI. Also, this gene delivery system showed nearly sixfold higher efficiency in the serum-containing condition than the control, so further application of these vehicles in vivo is highly appreciated. Besides, the trehalose containing lyophilized formulation could hold the availability for at least 4 months of storing at room temperature, presenting the potential for industrial production and transportation of gene therapy.

siRNA delivery system based on magnetic nanovectors: Characterization and stability evaluation

Gene therapy and particularly small interfering RNA (siRNA) is a promising therapeutic method for treatment of various human diseases, especially cancer. However the lack of an ideal delivery system limits its clinical applications. Effective anticancer drug development represents the key for translation of research advances into medicines. Previously we reported, the optimization of magnetic siRNA nanovectors (MSN) formulation based on superparamagnetic iron oxide nanoparticles (SPION) and chitosan for systemic administration. This work aimed at using rational design to further optimize and develop MSN. Therefore, formulated MSN were first purified, then their physical and chemical properties were studied mainly through capillary electrophoresis. 95% of siRNA was found enclosed within the purified MSN (pMSN). pMSN showed colloidal stability at pH 7.4, effective protection of siRNA against ribonuclease degradation up to 24 hours and few siRNA release (less than 10%) at pH 7.4. These findings push toward further evaluation studies in vitro and/or in vivo, indicating the appropriateness of pMSN for cancer theranostics.

Engineering the RNA-Nanobio Interface

RNA nanotechnology is attracting a great deal of attention recently. As the multiple roles that RNA plays in molecular biology and physiological regulation become clearer, there are many opportunities for engineering RNA-Nanoparticle Complexes (RNA-NPCs). The high “engineerability” of RNA-NPCs comes from the ability to modify the RNA and NP chemistry. For example, the NP can be derived from materials with anticancer activity and the RNA delivered by it, designed to target cell signaling pathways that contribute to the molecular basis of these diseases. Despite this rapid advancement and the availability of new quantification and characterization techniques, a key challenge is to develop a better understanding of the RNA-nanobio interface; that is, the interactions of RNA with NP (RNA-nanobio interface) and how that impacts the structure, function, delivery, and activity of the RNA. Here, we attempt to summarize the state-of-the-art in this new and exciting field, and to lay out potential directions for bioengineering research on RNA-NPCs.

Promising gene delivery system based on polyethylenimine-modified silica nanoparticles

This article reports on the synthesis and full characterization of innovative silica-based nanoparticle composed of fumed silica as a core decorated with polyethylenimine (PEI) with different molecular weights (25, 10 and 1.8 kDa). Wide range of analytical, spectroscopic, and microscopic methods (TEM, DLS, ζ potential, elemental analysis (EA), TNBS and FTIR) were used to characterize the nanoparticles. Furthermore, transfection efficiency of these nanoparticles as non-viral vector was examined. The silica-PEI conjugates retained both the ability of PEI to fully condense plasmid DNA at low N/P ratios and suitable buffering capacity at the endosomal pH range. PEI-functionalized silica remarkably enhanced EGFP-N1 gene expression in murine neuroblastoma (Neuro-2A) cells up to 38 folds compared to PEI 25 kDa. Meanwhile the results of the cytotoxicity assays indicated that these silica-PEI conjugates have acceptable level of viability.

Maghemite-containing PLGA–PEG-based polymeric nanoparticles for siRNA delivery: toxicity and silencing evaluation

Gene therapy based on siRNA has emerged as an exciting new therapeutic approach. In this work, incorporation of PEI into PLGA-b-PEG and encapsulation of magnetic NPs as MRI contrast agent, resulted in unique theranostic nanoparticles.

Efficient delivery of C/EBP beta gene into human mesenchymal stem cells via polyethylenimine-coated gold nanoparticles enhances adipogenic differentiation

The controlled differentiation of stem cells via the delivery of specific genes encoding appropriate differentiation factors may provide useful models for regenerative medicine and aid in developing therapies for human patients. However, the majority of non-viral vectors are not efficient enough to manipulate difficult-to-transfect adult human stem cells in vitro. Herein, we report the first use of 25 kDa branched polyethylenimine-entrapped gold nanoparticles (AuPEINPs) and covalently bound polyethylenimine-gold nanoparticles (AuMUAPEINPs) as carriers for efficient gene delivery into human mesenchymal stem cells (hMSCs). We determined a functional application of these nanoparticles by transfecting hMSCs with the C/EBP beta gene, fused to EGFP, to induce adipogenic differentiation. Transfection efficacy with AuPEINPs and AuMUAPEINPs was 52.3% and 40.7%, respectively, which was 2.48 and 1.93 times higher than that by using Lipofectamine 2000. Luciferase assay results also demonstrated improved gene transfection efficiency of AuPEINPs/AuMUAPEINPs over Lipofectamine 2000 and polyethylenimine. Overexpression of exogenous C/EBP beta significantly enhanced adipogenesis in hMSCs as indicated by both of Oil Red O staining and mRNA expression analyses. Nanoparticle/DNA complexes exhibited favorable cytocompatibility in hMSCs. Taken together, AuPEINPs and AuMUAPEINPs potentially represent safe and highly efficient vehicles for gene delivery to control hMSC differentiation and for therapeutic gene delivery applications.

Amino acid-based anti-fouling functionalization of silica nanoparticles using divinyl sulfone

Natural amino acids are zwitterionic molecules and the good biocompatibility promises them potential candidates as anti-fouling materials. Here, we developed a new method to functionalize silica nanoparticles with a natural amino acid-based anti-fouling layer. Amino acids were covalently immobilized on 3-aminopropyltriethoxysilane modified silica nanoparticles using divinyl sulfone through a two-step reaction in aqueous solution at room temperature. The progress was monitored with NMR, X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM) and zeta potential measurements. A library of amino acids was screened and the nonspecific protein adsorption of bovine serum albumin (BSA) and fetal bovine serum (FBS) were investigated using dynamic light scattering method. The results showed that cysteine, lysine and arginine functionalized silica nanoparticles can effectively resist protein adsorption due to the zwitterionic structure. Among them, lysine functionalized silica nanoparticles had the best anti-fouling performance, which showed hydrodynamic diameter increases of only 10% after incubated in BSA solution and 20% after incubated in FBS solution for 24h. The neat aqueous modification process can conveniently create a thin zwitterionic layer on silica particles, and it has a great potential in biomolecule immobilization and biofunctional surface preparation.

STATEMENT OF SIGNIFICANCE

Zwitterionic polymer is an outstanding class of anti-fouling material; but the difficulty in synthesis is challenging its spread utilization. In this study, we developed a new method to create an amino acid-based zwitterionic layer on APTES functionalized silica nanoparticles through a two-step reaction in aqueous solution at room temperature. The surface chemistry was monitored with NMR, XPS, TEM and zeta potential measurements. With this method, a library of amino acid conjugated-silica nanoparticles was synthesized and their anti-fouling performance was evaluated using dynamic light scattering method. The results showed that the cysteine, lysine and arginine conjugated nanoparticles all can effectively resist nonspecific protein adsorption. Among them, lysine conjugated nanoparticles show the best anti-fouling performance, which showed hydrodynamic diameter increases of only 10% after incubated in BSA solution and 20% after incubated in FBS solution for 24 hours. These results indicates that the anti-fouling silica nanoparticles are of great potential in many biomedical applications, especially biosensing and diagnose imaging. The modification reactions in aqueous solution at room temperature are easily conducted in laboratory, indicating high potential in the functionalization of silica particles/surfaces with other biomolecules.

Hybrid Antifouling and Antimicrobial Coatings Prepared by Electroless Co-Deposition of Fluoropolymer and Cationic Silica Nanoparticles on Stainless Steel: Efficacy against Listeria monocytogenes

Controlling formation, establishment, and proliferation of microbial biofilms on surfaces is critical for ensuring public safety. Herein, we report on the synthesis of antimicrobial nanoparticles and their co-deposition along with fluorinated nanoparticles during electroless nickel plating of stainless steel. Plating bath composition is optimized to ensure sufficiently low surface energy to resist fouling and microbial adhesion as well as to exert significant (>99.99% reduction) antimicrobial activity against Listeria monocytogenes. The resulting coatings present hybrid antifouling and antimicrobial character, can be applied onto stainless steel, and do not rely on leaching or migration of the antimicrobial nanoparticles to be effective. Such coatings can support reducing public health issues related to microbial cross-contamination in areas such as food processing, hospitals, and water purification.

Vectorization of Nucleic Acids for Therapeutic Approach: Tutorial Review

Oligonucleotides present a high therapeutic potential for a wide variety of diseases. However, their clinical development is limited by their degradation by nucleases and their poor blood circulation time. Depending on the administration mode and the cellular target, these macromolecules will have to cross the vascular endothelium, to diffuse through the extracellular matrix, to be transported through the cell membrane, and finally to reach the cytoplasm. To overcome these physiological barriers, many strategies have been developed. Here, we review different methods of DNA vectorization, discuss limitations and advantages of the various vectors, and provide new perspectives for future development.

Histone-inspired biomimetic polymeric gene vehicles with excellent biocompatibility and enhanced transfection efficacy

Histone-inspired biomimetic polymeric gene vectors show great biocompatibility and enhanced transfection efficacy.

Deferasirox loaded on fumed silica nanoparticles used in cancer treatment

Fumed silica nanoparticles loaded with deferasirox are three and five times more cytotoxic than cisplatin and deferasirox against MDA-MB-23, respectively.

Enhanced binding capacity of boronate affinity fibrous material for effective enrichment of nucleosides in urine samples

A novel polyethyleneimine-modified boronate affinity fibrous cotton with high binding capacity was prepared for in-pipette-tip solid phase extraction nucleosides in human urine.

Deferasirox-coated iron oxide nanoparticles as a potential cytotoxic agent

Two broad strategies for the use of iron chelators in cancer treatment have been explored.

Impact of Polyethylenimine Conjugation Mode on the Cell Transfection Efficiency of Silica Nanovectors

The conjugation of polyethylenimine (PEI) to silica nanoparticles has emerged as a useful strategy in gene delivery. Here we investigate the influence of the PEI conjugation mode on the transfection ability of plain silica nanoparticles. Surface functionalization with sulfonate- and chloride-bearing silanes modulates the amount and conformation of PEI and therefore the particles' affinity for the plasmid, without impacting on cytotoxicity. However, transfection efficiency in both immortalized and primary cells is more directly correlated to the nature and strength of the particle-PEI interactions. It suggests that PEI detachment from the particle surface at the stage of endosomal escape is a key event in the plasmid delivery process. These data should provide fruitful guidelines for the fine tuning of colloidal surfaces intended for intracellular delivery of bioactive molecules.

Iron Oxide Nanoparticles Coated with a Phosphorothioate Oligonucleotide and a Cationic Peptide: Exploring Four Different Ways of Surface Functionalization

The superparamagnetic iron oxide nanoparticles (SPIONs) have great potential in therapeutic and diagnostic applications. Due to their superparamagnetic behavior, they are used clinically as a Magnetic Resonance Imaging (MRI) contrast agent. Iron oxide nanoparticles are also recognized todays as smart drug-delivery systems. However, to increase their specificity, it is essential to functionalize them with a molecule that effectively targets a specific area of the body. Among the molecules that can fulfill this role, peptides are excellent candidates. Oligonucleotides are recognized as potential drugs for various diseases but suffer from poor uptake and intracellular degradation. In this work, we explore four different strategies, based on the electrostatic interactions between the different partners, to functionalize the surface of SPIONs with a phosphorothioate oligonucleotide (ODN) and a cationic peptide labeled with a fluorophore. The internalization of the nanoparticles has been evaluated in vitro on RAW 264.7 cells. Among these strategies, the "«one-step assembly»", i.e., the direct complexation of oligonucleotides and peptides on iron oxide nanoparticles, provides the best way of coating for the internalization of the nanocomplexes.

Acute in vivo toxicity mitigation of PEI-coated maghemite nanoparticles using controlled oxidation and surface modifications toward siRNA delivery

A ceric ammonium nitrate (CAN)-based doping step was used for the fabrication of core maghemite nanoparticles (NPs) that enabled the obtainment of colloid particles with a view to a high-level nanoparticle (NP) surface doping by Ce(III/IV). Such doping of Ce(III/IV) cations enables one to exploit their quite rich coordination chemistry for ligand coordinative binding. In fact, they were shown to act as powerful Lewis acid centers for attaching any organic (Lewis base) ligand such as a 25 kDa branched PEI polymer. Resulting conPEI25-CAN-γ-Fe2O3 NPs have been fully characterized before a successful implementation of siRNA loading and cell delivery/gene silencing using a well-known dual luciferase system. This attractive result emphasized their significant potential as an NP platform technology toward additional MRI and/or drug delivery (peptide)-relating end applications. However, due to their high positive charge, PEI polymers can cause severe in vivo toxicity due to their interaction with negatively charged red blood cells (RBC), resulting in RBC aggregation and lysis, leading to thrombosis and, finally, to animal death. In order to mitigate these acute toxic effects, two different types of surface modifications were performed. One modification included the controlled oxidation of 0.1-5% of the PEI amines before or after conjugation to the NPs, using hydrogen peroxide or potassium persulfate. The other type of modification was the addition of a second biocompatible polyanionic polymer to the PEI grafted NPs, based on the concept of a layer-by-layer (LbL) technique. This modification is based on the coordination of another polyanionic polymer on the NPs surface in order to create a combined hybrid PEI and polyanionic polymer nanosystem. In both cases, the surface modification successfully mitigated the NP acute in vivo toxicity, without compromising the silencing efficiency.

MagRET Nanoparticles: An Iron Oxide Nanocomposite Platform for Gene Silencing from MicroRNAs to Long Noncoding RNAs

Silencing of RNA to knock down genes is currently one of the top priorities in gene therapies for cancer. However, to become practical the obstacle of RNA delivery needs to be solved. In this study, we used innovative maghemite (γ-Fe2O3) nanoparticles, termed magnetic reagent for efficient transfection (MagRET), which are composed of a maghemite core that is surface-doped by lanthanide Ce(3/4+) cations using sonochemistry. Thereafter, a polycationic polyethylenimine (PEI) polymer phase is bound to the maghemite core via coordinative chemistry enabled by the [CeL(n)](3/4+)cations/complex. PEI oxidation was used to mitigate the in vivo toxicity. Using this approach, silencing of 80-100% was observed for mRNAs, microRNAs, and lncRNA in a variety of cancer cells. MagRET NPs are advantageous in hard to transfect leukemias. This versatile nanoscale carrier can silence all known types of RNAs and these MagRET NPs with oxidized PEI are not lethal upon injection, thus holding promise for therapeutic applications, as a theranostic tool.

Unique Surface Modification of Silica Nanoparticles with Polyethylenimine (PEI) for siRNA Delivery Using Cerium Cation Coordination Chemistry

The discovery of RNA interference (RNAi) as a naturally occurring mechanism for gene knockdown has attracted considerable attention toward the use of small interfering RNAs (siRNAs) for therapeutic purposes. The main obstacles of harnessing siRNAs as drugs are their inefficient delivery to cells and off-target effect making clinical applications very challenging. The positively charged, branched 25 kDa polyethylenimine (b-PEI) polymer is widely regarded as one of the most efficient nonviral commercially available transfection agents. However, it has also been shown that 25 kDa b-PEI is highly cytotoxic and can readily lead to cell death. In this specific context, this study presents the preparation and characterization of innovative 25 kDa b-PEI-decorated polycationic silica nanoparticles (SiO2 NPs) for cellular siRNA delivery and subsequent gene silencing. A new method of b-PEI attachment onto the SiO2 NP surface has been developed that makes use of cerium(III) cations (Ce(3+)), a lanthanide group element, as an effective noncovalent inorganic linker between both polyNH2-SiO2 nanoparticle (SPA NPs) surface and polycationic 25 kDa b-PEI polymer. Two resulting novel SPA-Ce-PEI NPs consist of similar amounts of b-PEI, while possessing different amounts of Ce(3+). Various analytical techniques (TEM, DLS, ζ potential, ICP-AES, and TGA) have been used to deeply characterize NPs physicochemical qualities. The observed results of Ce(3+)-dependent gene silencing and cytotoxic activities led us to conclusions about the role of Ce(3+)-N bonding during the chemical attachment of the 25 kDa b-PEI shell onto the NP surface.

Local and sustained gene delivery in silica-collagen nanocomposites

Local delivery of biomolecules from hydrogels is highly challenging because of their rapid diffusion and degradation. Gene therapy represents an alternative that allows for the prolonged production of proteins by transfected cells. In this study, we have developed nanocomposites consisting of DNA-polyethylenimine-silica nanoparticle complexes coencapsulated with fibroblasts within collagen hydrogels. Through the modulation of the particle size and polyethylenimine molecular weight, it was possible to achieve "in-gel" transfection permitting the sustained production of biomolecules from hydrogels over 1 week. Alternative configurations consisting of particle addition to cellularized gels and cell culture in the presence of complex-containing hydrogels were also investigated. These studies demonstrated that particle encapsulation limits DNA and silica dissemination outside the collagen hydrogels. They also show the key role of cell proliferation within collagen hydrogels on the transfection efficiency. Such nanocomposites therefore constitute promising materials for the development of novel gene delivery systems to promote tissue repair.