Simulated Biological Media Research Articles

Multifunctional nanoplatforms based on alumina-coated mesoporous silica with potential for cancer theranostics applications

Multifunctional nanoplatforms based on mesoporous silica coated with alumina were successfully and sustainably synthesized using sodium silicate extracted from rice husk ash (RHA), demonstrating the potential for cancer theranostics. The hybrid nanostructures produced (C2-600 and C4-600), from two different calcination times, exhibited distinct morphologies, textural parameters, and degrees of mesoscopic organization. As expected, the Al2O3 coating on the mesoporous silica nanoparticles (MSNs) reduced the specific surface area from 720 m2/g to 122 m2/g (C2-600) and 57 m2/g (C4-600), while preserving their mesoporous structure. Additionally, both C2-600 and C4-600 showed relatively good stability across a wide pH interval, with a zeta potential of ζ = -15 mV and hydrodynamic diameter (Dh) ranging from 160 to 670 nm, depending on the pH of the medium. These peculiar characteristics resulted in high encapsulation efficiency (EE ≈ 90%) for the doxorubicin (DOX) anticancer drug, as well as sustained drug release in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.4). Appreciably, C4-600-DOX released approximately 83% of the drug over 96 hours and demonstrated significant biodegradation in simulated biological media. Furthermore, the hybrid nanoplatforms exhibited strong optical absorption between 250 and 420 nm, along with broad and intense photoluminescence (PL) in the near-infrared (NIR) region (680-900 nm), which is highly desirable for NIR-fluorescence diagnostic imaging. Notably, the hybrid nanoplatforms without DOX were non-cytotoxic to fibroblast and Caco-2 cells, while the DOX-loaded nanoplatforms exhibited selectivity and potent anticancer activity, inhibiting approximately 80% of Caco-2 colorectal cancer cells after 72 hours. These findings demonstrate that C2-600 and C4-600 are innovative, multifunctional and biodegradable nanoplatforms with powerful potential as drug carriers and fluorescence imaging agents, making them promising candidates for cancer theranostics.

Evaluation of heteroscorpionate ligands as scaffolds for the generation of Ruthenium(II) metallodrugs in breast cancer therapy

The modular synthesis of the heteroscorpionate core is explored as a tool for the rapid development of ruthenium-based therapeutic agents. Starting with a series of structurally diverse alcohol-NN ligands, a family of heteroscorpionate-based ruthenium derivatives was synthesized, characterized, and evaluated as an alternative to platinum therapy for breast cancer therapy. In vitro, the antitumoral activity of the novel derivatives was assessed in a series of breast cancer cell lines using UNICAM-1 and cisplatin as metallodrug control. Through this approach, a bimetallic heteroscorpionate-based metallodrug (RUSCO-2) was identified as the lead compound of the series with an IC50 value range as low as 3–5 μM. Notably, RUSCO-2 was found to be highly cytotoxic in TNBC cell lines, suggesting a mode of action independent of the receptor status of the cells. As a proof of concept and taking advantage of the luminescent properties of one of the complexes obtained, uptake was monitored in human breast cancer MCF7 cell lines by fluorescence lifetime imaging microscopy (FLIM) to reveal that the compound is evenly distributed in the cytoplasm and that the incorporation of the heteroscorpionate ligand protects it from aqueous processes, conversion in another entity, or the loss of the chloride group. Finally, ROS studies were conducted, lipophilicity was estimated, the chloride/water exchange was studied, and stability studies in simulated biological media were carried out to propose structure-activity relationships.

The Impact of the Addition of Vitamins on a Silicone Lining Material to the Oral Mucosa Tissue-Evaluation of the Biocompatibility, Hydrolytic Stability and Histopathological Effect.

Background and Objectives: One's quality of life depends on overall health, and in particular, oral health, which has been and continues to become a public health issue through frequent manifestations in various forms, from simple oral stomatitis (inflammations of the oral cavity) to the complicated oral health pathologies requiring medical interventions and treatments (caries, pulp necrosis and periodontitis). The aim of this study focused on the preparation and evaluation of vitamins (vitamin A, B1 and B6) incorporated into several silicone-based lining materials as a new alternative to therapeutically loaded materials designed as oral cavity lining materials in prosthodontics. Materials and Methods: Silicone-based liners containing vitamins were prepared by mixing them in solution and becoming crosslinked, and then they were characterized using Fourier-transform infrared (FT-IR) spectroscopy to confirm the incorporation of the vitamins into the silicone network; scanning electron microscopy (SEM) to evidence the morphology of the liner materials; dynamic vapor sorption (DVS) to evaluate their internal hydrophobicity, swelling in environments similar to biological fluids and mechanical test to demonstrate tensile strength; MTT to confirm their biocompatibility on normal cell cultures (fibroblast) and mucoadhesivity; and histopathological tests on porcine oral mucosa to highlight their potential utility as soft lining materials with improved efficiency. Results: FT-IR analysis confirmed the structural peculiarities of the prepared lining materials and the successful incorporation of vitamins into the silicone matrix. The surface roughness of the materials was lower than 0.2 μm, while in cross-section, the lining materials showed a compact morphology. It was found that the presence of vitamins induced a decrease in the main mechanical parameters (strength and elongation at break, Young's modulus) and hydrophobicity, which varied from one vitamin to another. A swelling degree higher than 8% was found in PBS 6.8 (artificial saliva) and water. Hydrolytic stability studies in an artificial saliva medium showed the release of low concentrations of silicone and vitamin fragments in the first 24 h, which increased the swelling behavior of the materials, diffusion and solubility of the vitamins. The microscopic images of fibroblast cells incubated with vitamin liners revealed very good biocompatibility. Also, the silicone liners incorporating the vitamins showed good mucoadhesive properties. The appearance of some pathological disorders with autolysis processes was more pronounced in the case of vitamin A liners. Conclusions: The addition of the vitamins was shown to have a beneficial effect that was mainly manifested as increased biocompatibility, hydrolytic stability and mucoadhesiveness with the mucosa of the oral cavity and less of an effect on the mechanical strength. The obtained lining materials showed good resistance in simulated biological media but caused a pronounced autolysis phenomenon, as revealed by histopathological examination, showing that these materials may have broad implications in the treatment of oral diseases.

Salts of S-(+)-Ibuprofen Formed via Its Reaction with the Antifibrinolytic Agents Aminocaproic Acid and Tranexamic Acid: Synthesis and Characterization

The paucity of multi-component compounds containing the non-steroidal anti-inflammatory drug (NSAID) S-(+)-ibuprofen (S-IBU) in combination with other drugs prompted the present study, which describes 1:1 salts of this active pharmaceutical ingredient (API) with the two most widely used antifibrinolytic APIs, namely 6-aminohexanoic acid (aminocaproic acid, ACA) and tranexamic acid (TXA), which are zwitterions in the solid state. Since NSAIDs are known to cause adverse side effects such as gastrointestinal ulceration, the presence of ACA and TXA in the salts with S-(+)-ibuprofen might counter these effects via their ability to prevent excessive bleeding. The salts were prepared by both the liquid-assisted grinding method and co-precipitation and were characterized by X-ray powder diffraction and single-crystal X-ray diffraction, thermal analysis, Fourier transform infrared spectroscopy, and solubility measurements. The X-ray analyses revealed a high degree of isostructurality, both at the level of their respective asymmetric units and in their extended crystal structures, with charge-assisted hydrogen bonds of the type N-H+⋅⋅⋅O− and O-H+⋅⋅⋅O− featuring prominently. The thermal analysis indicated that both salts had significantly higher thermal stability than S-(+)-ibuprofen. Solubility measurements in a simulated biological medium showed insignificant changes in the solubility of S-(+)-ibuprofen when tested in the form of the salts (S-IBU)−(ACA)+ and (S-IBU)−(TXA)+.

Characterizing the interaction between micro(nano)plastics and simulated body fluids and their impact on human lung epithelial cells.

Micro(nano)plastics are considered an emerging threat to human health because they can interact with biological systems. In fact, these materials have already been found in the human body, such as in the lungs. However, limited data are available on the behavior of these materials under biological conditions and their impact on human cells, specifically on alveolar epithelial cells. In this study, micro(nano)plastics were exposed to various simulated biological fluids (artificial lysosomal fluids and Gamble's solution) for 2-80 h. Pristine and treated plastic particles were characterized based on their surface chemistry, zeta potentials, and elemental composition. Various toxicological endpoints (mitochondrial membrane potential, lactate dehydrogenase, protein, and antioxidant levels) were examined using A549 lung carcinoma cells. The surface characteristics of the treated micro(nano)plastics and the toxicological endpoints of A549 cells were found to be influenced by the simulated biological media, specifically with high concentrations of the treated micro(nano)plastics and increasing exposure under biological conditions. Moreover, the toxicological endpoints were strongly linked to the chemistry of plastics and included multiple processes in response to the plastics; different biological pathways were obtained in artificial lysosomal fluid and Gamble's solution.

Smart transformation of bowl shape chitosan nanomotors to disc shape in simulated biological media and consequent controlled velocity

The design of nanomotors appropriate for targeted drug delivery to cancer cells have been extensively investigated in recent years. By Pickering emulsion method, nanomotors based on platinum nanoparticles and chitosan chains were synthesized and placed on a substrate of SiO2 nanoparticles using a crosslinking agent containing a disulfide bond. The SiO2 fraction was removed, and the final chitosan-platinum nanomotor was prepared with a bowl-shaped structure. Platinum is the motor of this particle and leads to the movement of nanoparticles in the presence of H2O2 fuel. Therefore, it predicts this nanomotor can move toward the media with higher concentration of peroxide, like cancerous tissues. This nanomotor is designed in such a way that by reaching the media with higher concentration of dithiothreitol (DTT), it stops. This controllability is derived from the change in the morphology of nanomotors from bowl-shape to disc-shape. The results showed that the synthesized nanomotor could act as a biosensor for detecting cancer cells because it is sensitive to specific factors such as pH, H2O2, and DTT. The minimum required values of H2O2 and DTT needed to move the nanomotors were determined by chronoamperometry and found to be 0.1 and 2%, respectively. The release of quercetin as an anti-cancer drug from the nanomotor showed that at acidic pH, the presence of H2O2 and DTT increases the drug release compared to normal conditions. The result of the MTT assay also confirmed that the nanomotors showed more toxicity in the presence of more H2O2 in cancer cells.

Native Study of the Behaviour of Magnetite Nanoparticles for Hyperthermia Treatment during the Initial Moments of Intravenous Administration.

Magnetic nanoparticles (MNPs) present outstanding properties making them suitable as therapeutic agents for hyperthermia treatments. Since the main safety concerns of MNPs are represented by their inherent instability in a biological medium, strategies to both achieve long-term stability and monitor hazardous MNP degradation are needed. We combined a dynamic approach relying on flow field flow fractionation (FFF)-multidetection with conventional techniques to explore frame-by-frame changes of MNPs injected in simulated biological medium, hypothesize the interaction mechanism they are subject to when surrounded by a saline, protein-rich environment, and understand their behaviour at the most critical point of intravenous administration. In the first moments of MNPs administration in the patient, MNPs change their surrounding from a favorable to an unfavorable medium, i.e., a complex biological fluid such as blood; the particles evolve from a synthetic identity to a biological identity, a transition that needs to be carefully monitored. The dynamic approach presented herein represents an optimal alternative to conventional batch techniques that can monitor only size, shape, surface charge, and aggregation phenomena as an averaged information, given that they cannot resolve different populations present in the sample and cannot give accurate information about the evolution or temporary instability of MNPs. The designed FFF method equipped with a multidetection system enabled the separation of the particle populations providing selective information on their morphological evolution and on nanoparticle-proteins interaction in the very first steps of infusion. Results showed that in a dynamic biological setting and following interaction with serum albumin, PP-MNPs retain their colloidal properties, supporting their safety profile for intravenous administration.

Hydroxypropyl Cellulose/Pluronic-Based Composite Hydrogels as Biodegradable Mucoadhesive Scaffolds for Tissue Engineering.

Recently, the development of new materials with the desired characteristics for functional tissue engineering, ensuring tissue architecture and supporting cellular growth, has gained significant attention. Hydrogels, which possess similar properties to natural cellular matrixes, being able to repair or replace biological tissues and support the healing process through cellular proliferation and viability, are a challenge when designing tissue scaffolds. This paper provides new insights into hydrogel-based polymeric blends (hydroxypropyl cellulose/Pluronic F68), aiming to evaluate the contributions of both components in the development of new tissue scaffolds. In order to study the interactions within the hydrogel blends, FTIR and 1HNMR spectroscopies were used. The porosity and the behavior in moisture medium were highlighted by SEM and DVS analyses. The biodegradability of the hydrogel blends was studied in a simulated biological medium. The hydrogel composition was determinant for the scaffold behavior: the HPC component was found to have a great influence on the BET and GAB areas, on the monolayer values estimated from sorption–desorption isotherms and on mucoadhesivity on small intestine mucosa, while the Pluronic F68 component improved the thermal stability. All blends were also found to have good mechanical strength and increased biocompatibility on the NHDF cell line. Based on their particular compositions and increased mucoadhesivity on small intestine mucosa, these polymeric blends could be effective in the repair or recovery of damaged cell membranes (due to the contribution of Pluronic F68) or in control drug-delivery intestinal formulations.

Mucoadhesive and Antimicrobial Allantoin/β Cyclodextrins-Loaded Carbopol Gels as Scaffolds for Regenerative Medicine.

Allantoin and its β-cyclodextrin and hydroxypropyl-β-cyclodextrin inclusion complexes 1:1 have been used to prepare carbopol-based mucoadhesive gels. The gelation process occurred by adjustment with glycerol 10% in the presence of triethanolamine. The structural features induced by the presence of allantoin and the corresponding β-cyclodextrins inclusion complexes have been first investigated by infrared spectroscopy highlighting strong interactions within the gels network and ideal crosslinks for the self-healing behavior. The hydrophilicity of the gels was investigated by the determination of the surface tension parameters and the free energy of hydration. The interfacial free energy values indicated prolonged biocompatibility with blood. The gels-water molecule interactions in terms of sorption, permeability, and diffusion coefficients were evaluated by dynamic vapor sorption analysis. The self-assembly process through intermolecular H-bonding, the high hydrophilicity, the mechanical performance, the hydrolytic stability in simulated biological media, the biocompatibility with normal human dermal fibroblast (NHDF) cells, the mucoadhesivity and antimicrobial activity on selected microorganism species (S. Aureus and C. albicans) of the allantoin-based gels recommend them as promising scaffold alternatives in regenerative medicine.

A 3D macroporous and magnetic Mg2SiO4-CuFe2O4 scaffold for bone tissue regeneration: Surface modification, in vitro and in vivo studies.

Macroporous scaffolds with bioactivity and magnetic properties can be a good candidate for bone regeneration and hyperthermia. In addition, modifying the surface of the scaffolds with biocompatible materials can increase their potential for in vivo applications. Here, we developed a multifunctional nanocomposite Mg2SiO4-CuFe2O4 scaffold for bone regeneration and hyperthermia. The surface of scaffold was coated with various concentrations of poly-3-hydroxybutyrate (P3HB, 1-5% (w/v)). It was observed that 3% (w/v) of P3HB provided a favorable combination of porosity (79±2.1%) and compressive strength (3.2±0.11MPa). The hyperthermia potential of samples was assessed in the presence of various magnetic fields in vitro. The coated scaffolds showed a lower degradation rate than the un-coated one up to 35days of soaking in simulated biological medium. Due to the porous and specific morphology of P3HB, it was found that in vitro bioactivity and cell attachment were increased on the scaffold. Moreover, it was observed that the P3HB coating improved the cell viability, alkaline phosphatase activity, and mineralization of the scaffold. Finally, we studied the bone formation ability of the scaffolds in vivo, and implanted the developed scaffold in the rat's femur for 8weeks. Micro-computed tomography results including bone volume fraction and trabecular thickness exhibited an improvement in the bone regeneration of the coated scaffold compared to the control. The overall results of this study introduce a highly macroporous scaffold with multifunctional performance, noticeable ability in bone regeneration, and hyperthermia properties for osteosarcoma.

Smart Transformation of Bowl Shape Chitosan Micromotors to Disc Shape in Simulated Biological Media and Consequent Controlled Velocity

Smart Transformation of Bowl Shape Chitosan Micromotors to Disc Shape in Simulated Biological Media and Consequent Controlled Velocity

Water-powered self-propelled magnetic nanobot for rapid and highly efficient capture of circulating tumor cells

Nanosized robots with self-propelling and navigating capabilities have become an exciting field of research, attributable to their autonomous motion and specific biomolecular interaction ability for bio-analysis and diagnosis. Here, we report magnesium (Mg)-Fe3O4-based Magneto-Fluorescent Nanorobot (“MFN”) that can self-propel in blood without any other additives and can selectively and rapidly isolate cancer cells. The nanobots viz; Mg-Fe3O4-GSH-G4-Cy5-Tf and Mg-Fe3O4-GSH-G4-Cy5-Ab have been designed and synthesized by simple surface modifications and conjugation chemistry to assemble multiple components viz; (i) EpCAM antibody/transferrin, (ii) cyanine 5 NHS (Cy5) dye, (iii) fourth generation (G4) dendrimers for multiple conjugation and (iv) glutathione (GSH) by chemical conjugation onto one side of Mg nanoparticle. The nanobots propelled efficiently not only in simulated biological media, but also in blood samples. With continuous motion upon exposure to water and the presence of Fe3O4 shell on Mg nanoparticle for magnetic guidance, the nanobot offers major improvements in sensitivity, efficiency and speed by greatly enhancing capture of cancer cells. The nanobots showed excellent cancer cell capture efficiency of almost 100% both in serum and whole blood, especially with MCF7 breast cancer cells.

COMPARATIVE OF NATURAL ZEOLITE – CLINOPTILOLITE ELIMINATION OF METAL IONS/ESPECIALLY Cu (II) WITH D-PENICILLAMINE FROM BIOLOGICAL ENVIRONMENTS

Clinoptilolite is used as an adsorbent to remove heavy metal cations due to its function as a molecular sieve. This molecular sieve characteristic has made it possible to study the efficiency of clinoptilolite and D-Penicillamine in a comparative way in terms of the adsorption of heavy metals (especially copper) from a biological medium. For this purpose, clinoptilolite was subjected to grinding to produce a homogenized micronized powder in two sizes with d90=75 and 150 μm. Then, initial adsorption tests in an aqueous medium were performed on 10 ppm solutions of iron, zinc, copper, cadmium and nickel cations in single cation solutions, as well as a mixture of cations. In the next step, tests were performed to evaluate the adsorption of Cu2+ on clinoptilolite under different conditions. Experiments have been performed to investigate the effect of pH, temperature (T), adsorbent dosage, time and cation concentration in a simulated biological medium. According to the results, clinoptilolite has a high ability to remove metal cations from aqueous solutions. The 99.71% removal of copper cations by clinoptilolite indicates the high ability of this mineral to remove copper from any environment. In a simulated biological medium at pH=7 and 5, the copper adsorption rate was 98.18% and 97.45% respectively, which indicates the high ability of zeolite to absorb copper cations under biological conditions. An examination of the mass balance calculations has also shown the ability to replace clinoptilolite with penicillamine; 15 mg of clinoptilolite removes 214 mg of Cu from aqueous solutions, which is equivalent to the formation of copper-penicillamine chelate.

Electrical Interaction between Implantable Vagus Nerve Stimulation Device and Implantable Cardiac Rhythm Management Device.

Autonomic regulation therapy via vagus nerve stimulation (VNS) was recently approved as a therapy for chronic heart failure, and will likely be utilized in patients who are also indicated for cardiac rhythm management device implantation. This study is designed to assess the degree to which VNS is likely to cause interference in the cardiac sensing of an implantable cardiac rhythm management device. A VNS stimulation lead and a cardiac sensing lead were placed in a simulated biological medium. A nonconductive carrier frame was used to position the leads at a precise electrode spacing. Stimulation was delivered through the VNS Therapy lead at a maximum output current and a variety of combinations of stimulation frequencies from 5-30 Hz and stimulation pulse widths from 130-1000 μs. The electrode spacing began at 0 cm and was increased in 1 cm increments until the measured signal dropped below the cardiac rhythm management device noise floor for sensing. The test was conducted with both bipolar and unipolar sensing. In the bipolar sensing configuration, the maximum sensed signal amplitude was 687 μV at an electrode separation of 0 cm, signal frequency of 30 Hz, pulse width of 1000 μs, and output current of 3.5 mA. In the unipolar sensing configuration, the maximum amplitude was 406 μV. In both configurations, the measured signal with maximum stimulation intensity decreased significantly with electrode separation, and dropped below the noise floor at an electrode spacing of 3.0 cm. The sensed signal amplitude was further attenuated at lower stimulation amplitudes and pulse widths. Even at maximum neural stimulation intensity of 3.5 mA, at an electrode separation of at least 3.0 cm, neural stimulation did not result in a detectable level of interference with either bipolar or unipolar sensing. Because this separation is significantly smaller than the minimum electrode separation of 15 cm in clinical practice, VNS Therapy is not expected to interfere with the function of implantable cardiac devices.

A dinitro-functionalized metal-organic framework featuring visual and fluorogenic sensing of H2S in living cells, human blood plasma and environmental samples.

Here, we describe a new dinitro-functionalized Zr(iv) MOF (MOF = metal-organic framework) having a UiO-66 (UiO = University of Oslo) framework topology called UiO-66-(NO2)2 (1). It shows fluorescence turn-on behavior towards H2S in simulated biological medium (HEPES buffer, pH = 7.4). By employing solvothermal conditions, 1 was successfully synthesized by reacting ZrCl4, H2BDC-(NO2)2 [H2BDC-(NO2)2 = 2,5-dinitro-1,4-benzenedicarboxylic acid] ligand and benzoic acid with a molar ratio of 1 : 1 : 10 in DMF (DMF = N,N-dimethylformamide) at 130 °C for 24 h. The material was characterized by infrared spectroscopy, X-ray powder diffraction (XRPD) and thermogravimetric (TG) analyses. The compound not only displays highly sensitive fluorometric sensing of H2S but also exhibits a visually detectable colorimetric change towards H2S in daylight. Moreover, the high selectivity of 1' towards H2S is retained even when several other biologically intrusive species co-exist in the sensing medium. The limit of detection (LOD) of the compound is 14.14 μM which lies in the range of the H2S concentration found in biological systems. Fluorescence microscopy studies on J774A.1 cells revealed the efficacy of the probe for imaging H2S in living cells. Moreover, this material can detect H2S in human blood plasma (HBP) and monitor the sulfide concentration in real water samples. All these features clearly demonstrate that the material has huge potential for highly selective sensing of both extracellular and intracellular H2S.

Risedronate functionalized layered double hydroxides nanoparticles with bone targeting capabilities

Layered double hydroxides nanoparticles (LDH-NPs) are increasingly studied as drug nanocarriers for cellular delivery. Nevertheless, stable functionalizations providing targeting capabilities without disrupting the size of the carriers are necessary to achieve optimized performance. Here, LDH-NPs were functionalized with risedronate (Ris) to improve the osteotropicity of the nanocarriers without altering the nanosized distribution. Ris is a nitrogen containing bisphosphonate with rich acid-base reactivity that can lead Ris functionalized LDH-NPs also as pH-responsive drug nanocarriers. The current work is focused on the strategy to synthesize functionalized LDH-NPs with a maximum adsorption and a minimum intercalation of Ris while maintaining their nanosize. The speciation and interactions of Ris at the surface of LDH-NPs were analyzed using Raman microscopy whereas the functionalization stability and size distribution were checked in simulated biological media. Finally, pH sensitivity and hydroxyapatite binding capacity of Ris functionalized LDH-NPs were evaluated. HRis3− anions were incorporated to the LDH-NPs surface with high affinity providing with a negative zeta potential that controlled the size at around 100nm. The size of Ris functionalized LDH-NPs was not affected by the high ionic strength or the presence of proteins in simulated biological media. Further, the functionalization was stable against protein adsorption and anionic exchange. As expected, Ris functionalized LDH-NPs are bioresponsive with a high sensitivity for pH changes and specific affinity for hydroxyapatite, which makes them appealing drug nanocarriers for new bone therapies.

Lipid bilayer-coated curcumin-based mesoporous organosilica nanoparticles for cellular delivery

Effective and controlled drug delivery systems with on-demand release abilities and biocompatible properties receive enormous attention for biomedical applications. Here, we describe a novel inorganic–organic hybrid material with a strikingly high organic content of almost 50 wt%. The colloidal periodic mesoporous organosilica (PMO) nanoparticles synthesized in this work consist entirely of curcumin and ethane derivatives serving as constituents that are crosslinked by siloxane bridges, without any added silica. These mesoporous curcumin nanoparticles (MCNs) exhibit very high surface areas (ca. 1000 m2/g), narrow particle size distribution (around 200 nm) and a strikingly high stability in simulated biological media. Additionally, the MCNs show high autofluorescence and were used as a cargo delivery system in live-cell experiments. A supported lipid bilayer (SLB) efficiently seals the pores and releases Rhodamin B as model cargo in HeLa cells. This novel nanocarrier concept provides a promising platform for the development of controllable and highly biocompatible theranostic systems.

Tetanus toxoid-loaded layer-by-layer nanoassemblies for efficient systemic, mucosal, and cellular immunostimulatory response following oral administration.

The present study reports the tetanus toxoid (TT)-loaded layer-by-layer nanoassemblies (layersomes) with enhanced protection, permeation, and presentation for comprehensive oral immunization. The stable and lyophilized TT-loaded layersomes were prepared by a thin-film hydration method followed by alternate layer-by-layer coating of an electrolyte. The developed system was assessed for in vitro stability of antigen and formulation, cellular uptake, ex vivo intestinal uptake, and immunostimulatory response using a suitable experimental protocol. Layersomes improved the stability in simulated biological media as well as protected the integrity/conformation and native 3D structure of TT as confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), circular dichroism (CD), and fluorescence spectroscopy, respectively. The cell culture studies demonstrated a 3.8-fold higher permeation of layersomes in Caco-2 cells and an 8.5-fold higher uptake by antigen-presenting cells (RAW 264.7). The TT-loaded layersomes elicited a complete immunostimulatory profile consisting of higher systemic (serum IgG titer), mucosal (sIgA titer), and cellular (interleukin-2 (IL-2) and interferon-γ (IFN-γ) levels) immune response after peroral administration in mice. The modified TT inhibition assay further confirmed the elicitation of complete protective levels of anti-TT antibody (>0.1 IU/mL) by layersomes. In conclusion, the proposed strategy is expected to contribute significantly in the field of stable liposome technology for mass immunization through the oral route.

169. Polymer Functionalized Gold Nanoparticles in Gene Delivery In Vitro

Non-viral gene delivery approaches have been extensively studied as a basic tool for intracellular gene transfer and gene therapy especially for genetic aberrations including cancer. Gold nanoparticles have attracted strong biomedical interest for drug/gene delivery due to their low toxic nature, surface plasmon resonance and capability of increasing the stability of the payload. In the present study the synthesis of photoluminescent nanoparticles consisting of a gold core coated with polyethyleneimine, poly-L-lysine, cysteine and chitosan is reported. These functionalized gold nanoparticles (FAuNPs) were investigated at different pH values and ionic strength to identify the optimum conditions to produce stable monodisperse nanoparticles. FAuNPs showed good stability at low ionic strength which is important for the flexibility of the polymer chain. All nanoparticle/polymer formulations showed spherical particles in the size range 11.9-195 nm with narrow particle distributions and low PDI (<1.2). Nanoparticle and pDNA complexation was efficiently demonstrated in the band shift and ethidium bromide intercalation assays respectively, with serum nuclease digestion revealing partial protection of theResults: Our novel PEGylated PLGA nanoparticles (without siRNA) showed higher accumulation and extended residence time in the inflamed foot of lipopolysaccharide (LPS)-induced mouse model of chronic inflammation. TNF-α-siRNA-NPs were 176.6±15.8 nm in diameter, with a zeta potential of -25.2±2.0 mV and an entrapment efficiency of 31±4%. The nanoparticles were stable in simulated biological medium. In vitro, less than 40% of the siRNA was released with 72 h at 37oC. Finally, TNF-α-siRNA-NPs significantly decreased TNF-α release from J774A.1 cells.complexed plasmid DNA (pCMV-luc). MTT cytotoxicity experiments indicated that the FAuNPs elicited a dose dependent cytotoxic effect in four mammalian cell lines (HepG2, HEK293, HeLa and Caco2). Au-PEI/pDNA maintained over 80% cell viability across all cell lines, while the Au-cys/pDNA exhibited a significant 91.8% (p<0.001) in Caco2 cells, Au-Chit/pDNA 126% (p<0.01) in HepG2 cells and Au-PLL/pDNA 104% in Hela cells. Transfection studies were accomplished using the luciferase reporter gene assay. Results showed that the FAuNPs produced greater transgene activity than the cationic polymer/DNA complexes on their own. This was evident for the Au-PEI/pDNA complex which produced a 12 fold increase in the HEK293 cells and a 9 fold increase in the HepG2 cells, compared to the PEI/pDNA complexes. The results of this study suggest that FAuNP's low cytotoxicity coupled with the ability to parametrically control particle size and surface properties, make these nanoparticles suitable non-viral gene delivery vectors. However further engineering and modifications of the FAuNPs may be required to enable in vivo gene delivery.

Phosphorescent Coordination Polymer Nanoparticles as a Three-in-One Platform for Optical Imaging, T1-Weighted Magnetic Resonance Imaging, and Photodynamic Therapy

Water-soluble coordination polymer nanoparticles (Ir–Gd CPPs) were conveniently synthesized in high yields in the presence of polyvinylpyrrolidone (PVP), adopting magnetic Gd(III) ions, and phosphorescent iridium complexes with carboxyl groups as building blocks. The Ir–Gd CPPs showed good stability in simulated biological media and low cytotoxicity toward a model line of HeLa cancer cells. The Ir–Gd CPPs exhibited absorption in the visible region, red phosphorescence centered at 560 nm, and higher longitudinal relaxivity (r1) of ∼29.5 mM–1 s–1 in a 3 T MRI system. Furthermore, the effective uptake of Ir–Gd CPPs by HeLa cells was confirmed by confocal laser scanning microscopy and flow cytometry, suggesting they may be useful as an optical probe for living cells. The generation of 1O2 upon irradiation with a visible light prompted an investigation into the possibility of using Ir–Gd CPPs in photodynamic therapy. After incubation with 200 μg mL–1 of Ir–Gd CPPs for 6 h, the viability of HeLa cells was only ∼16.6% after irradiation with a visible light (λ > 400 nm, 300 mW cm–2).