Method for analysis of nanoparticle hemolytic properties in vitro

Novel Schiff bases of Vanillin: potent inhibitors of macrophage harbored Leishmania tropica

Due to limited chemotherapeutic options for leishmaniasis, novel synthetic compounds are gaining attention for evaluation against leishmaniasis. This study aimed to synthesize the compound's Schiff bases of Vanillin to investigate and evaluate their anti-leishmanial potentials against intracellular protozoan parasites Leishmania tropica. In the current study, the phenomena of synergism by designing Schiff bases with Vanillin enhances their desired importance. A total of five compounds Schiff bases of Vanillin were synthesized using different aromatic amines and Vanillin. The structural analysis of all the compounds was done through FT-IR (Fourier Transformer-Infrared), thin layer chromatography, and spectroscopic techniques such as 13C-NMR, mass spectrometry, and 1H-NMR. The antimicrobial properties of all the compounds ZI-1, ZI-2, BS-1, KH-1, and FA-2 against promastigotes and amastigotes forms of L. tropica were analyzed at three different concentrations 25, 50, and 100 µg/ml. The in-vitro MTT assay was performed to calculate the percent inhibition, IC50 values, and their cytotoxicity. The highest percent inhibition values against promastigote form of L. tropica were BS-1 53.78% at 25 µg/ml, ZI-2 66.95% at 50 µg/ml, and again ZI-2 76.92% at 100 µg/ml. Similarly, the highest percent inhibition values against intracellular amastigote stage were BS-1 55.77% at 25 µg/ml, ZI-2 67.78% at 50 µg/ml and again ZI-2 84.93% 100 µg/ml. The highest potency was recorded for BS-1 in both stages, with IC50 values of 9.83 and 4.27 µg/ml against promastigotes and intracellular amastigotes, respectively. The percent hemolysis as toxicity; the lowest percent hemolysis was recorded for ZI-1 at three different concentrations of 25, 50, 100 µg/ml of 2.60, 3.50, and 6.31, respectively. These results suggested that all the compounds exhibited anti-leishmanial activity, with BS-1 as the most potent. Further studies are suggested to increase the activity of compounds with structural modifications by the addition of some other synergistic, novel, and analogue compounds.

Recent Advances in the Polish Research on Polysaccharide-Based Nanoparticles in the Context of Various Administration Routes

Polysaccharides are the most abundant polymers in nature. They exhibit robust biocompatibility, reliable non-toxicity, and biodegradable character; thus, they are employed in multiple biomedical applications. The presence of chemically accessible functional groups on the backbone of biopolymers (amine, carboxyl, hydroxyl, etc.) makes them suitable materials for chemical modification or drug immobilisation. Among different drug delivery systems (DDSs), nanoparticles have been of great interest in scientific research in the last decades. In the following review, we want to address the issue of rational design of nanoparticle (NP)-based drug delivery systems in reference to the specificity of the medication administration route and resulting requirements. In the following sections, readers can find a comprehensive analysis of the articles published by authors with Polish affiliations in the last few years (2016-2023). The article emphasises NP administration routes and synthetic approaches, followed by in vitro and in vivo attempts toward pharmacokinetic (PK) studies. The 'Future Prospects' section was constructed to address the critical observations and gaps found in the screened studies, as well as to indicate good practices for polysaccharide-based nanoparticle preclinical evaluation.

Tenofovir-tethered gold nanoparticles as a novel multifunctional long-acting anti-HIV therapy to overcome deficient drug delivery-: an in vivo proof of concept

BACKGROUND

The adoption of Antiretroviral Therapy (ART) substantially extends the life expectancy and quality of HIV-infected patients. Yet, eliminating the latent reservoirs of HIV to achieve a cure remains an unmet need. The advent of nanomedicine has revolutionized the treatment of HIV/AIDS. The present study explores a unique combination of Tenofovir (TNF) with gold nanoparticles (AuNPs) as a potential therapeutic approach to overcome several limitations of the current ART.

RESULTS

TNF-tethered AuNPs were successfully synthesized. Cell viability, genotoxicity, haemolysis, and histopathological studies confirmed the complete safety of the preparation. Most importantly, its anti-HIV1 reverse transcriptase activity was ~ 15 folds higher than the native TNF. In addition, it exhibited potent anti-HIV1 protease activity, a much sought-after target in anti-HIV1 therapeutics. Finally, the in vivo biodistribution studies validated that the AuNPs could reach many tissues/organs, serving as a secure nest for HIV and overcoming the problem of deficient drug delivery to HIV reservoirs.

CONCLUSIONS

We show that the combination of TNF and AuNPs exhibits multifunctional activity, viz. anti-HIV1 and anti-HIV1 protease. These findings are being reported for the first time and highlight the prospects of developing AuNP-TNF as a novel next-generation platform to treat HIV/AIDS.

Fitness Landscape-Guided Engineering of Locally Supercharged Virus-like Particles with Enhanced Cell Uptake Properties

Protein-based nanoparticles are useful models for the study of self-assembly and attractive candidates for drug delivery. Virus-like particles (VLPs) are especially promising platforms for expanding the repertoire of therapeutics that can be delivered effectively as they can deliver many copies of a molecule per particle for each delivery event. However, their use is often limited due to poor uptake of VLPs into mammalian cells. In this study, we use the fitness landscape of the bacteriophage MS2 VLP as a guide to engineer capsid variants with positively charged surface residues to enhance their uptake into mammalian cells. By combining mutations with positive fitness scores that were likely to produce assembled capsids, we identified two key double mutants with internalization efficiencies as much as 67-fold higher than that of wtMS2. Internalization of these variants with positively charged surface residues depends on interactions with cell surface sulfated proteoglycans, and yet, they are biophysically similar to wtMS2 with low cytotoxicity and an overall negative charge. Additionally, the best-performing engineered MS2 capsids can deliver a potent anticancer small-molecule therapeutic with efficacy levels similar to antibody-drug conjugates. Through this work, we were able to establish fitness landscape-based engineering as a successful method for designing VLPs with improved cell penetration. These findings suggest that VLPs with positive surface charge could be useful in improving the delivery of small-molecule- and nucleic acid-based therapeutics.

Biophysical interactions of mixed lipid-polymer nanoparticles incorporating curcumin: Potential as antibacterial agent

The technology of lipid nanoparticles has a long history in drug delivery, which begins with the discovery of liposomes by Alec D Bangham in the 1960s. Since then, numerous studies have been conducted on these systems, and several nanomedicinal products that utilize them have entered the market, with the latest being the COVID-19 vaccines. Despite their success, many aspects of their biophysical behavior are still under investigation. At the same time, their combination with other classes of biomaterials to create more advanced platforms is a promising endeavor. Herein, we developed mixed lipid-polymer nanoparticles with incorporated curcumin as a drug delivery system for therapy, and we studied its interactions with various biosystems. Initially, the nanoparticle physicochemical properties were investigated, where their size, size distribution, surface charge, morphology, drug incorporation and stability were assessed. The incorporation of the drug molecule was approximately 99.8 % for a formulated amount of 10 % by weight of the total membrane components and stable in due time. The association of the nanoparticles with human serum albumin and the effect that this brings upon their properties was studied by several biophysical techniques, including light scattering, thermal analysis and circular dichroism. As a biocompatibility assessment, interactions with erythrocyte membranes and hemolysis induced by the nanoparticles were also studied, with empty nanoparticles being more toxic than drug-loaded ones at high concentrations. Finally, interactions with bacterial membrane proteins of Staphylococcus aureus and the antibacterial effect of the nanoparticles were evaluated, where the effect of curcumin was improved when incorporated inside the nanoparticles. Overall, the developed mixed nanoparticles are promising candidates for the delivery of curcumin to infectious and other types of diseases.

Exploring chitosan-shelled nanobubbles to improve HER2 + immunotherapy via dendritic cell targeting

Immunotherapy is a valuable approach to cancer treatment as it is able to activate the immune system. However, the curative methods currently in clinical practice, including immune checkpoint inhibitors, present some limitations. Dendritic cell vaccination has been investigated as an immunotherapeutic strategy, and nanotechnology-based delivery systems have emerged as powerful tools for improving immunotherapy and vaccine development. A number of nanodelivery systems have therefore been proposed to promote cancer immunotherapy. This work aims to design a novel immunotherapy nanoplatform for the treatment of HER2 + breast cancer, and specially tailored chitosan-shelled nanobubbles (NBs) have been developed for the delivery of a DNA vaccine. The NBs have been functionalized with anti-CD1a antibodies to target dendritic cells (DCs). The NB formulations possess dimensions of approximately 300 nm and positive surface charge, and also show good physical stability up to 6 months under storage at 4 °C. In vitro characterization has confirmed that these NBs are capable of loading DNA with good encapsulation efficiency (82%). The antiCD1a-functionalized NBs are designed to target DCs, and demonstrated the ability to induce DC activation in both human and mouse cell models, and also elicited a specific immune response that was capable of slowing tumor growth in mice in vivo. These findings are the proof of concept that loading a tumor vaccine into DC-targeted chitosan nanobubbles may become an attractive nanotechnology approach for the future immunotherapeutic treatment of cancer.

N-Acetyl-l-cysteine-Loaded Nanosystems as a Promising Therapeutic Approach Toward the Eradication of Pseudomonas aeruginosa Biofilms

Bacterial biofilms are a major health concern, mainly due to their contribution to increased bacterial resistance to well-known antibiotics. The conventional treatment of biofilms represents a challenge, and frequently, eradication is not achieved with long-lasting administration of antibiotics. In this context, the present work proposes an innovative therapeutic approach that is focused on the encapsulation of N-acetyl-l-cysteine (NAC) into lipid nanoparticles (LNPs) functionalized with d-amino acids to target and disrupt bacterial biofilms. The optimized formulations presented a mean hydrodynamic diameter around 200 nm, a low polydispersity index, and a high loading capacity. These formulations were stable under storage conditions up to 6 months. In vitro biocompatibility studies showed a low cytotoxicity effect in fibroblasts and a low hemolytic activity in human red blood cells. Nevertheless, unloaded LNPs showed a higher hemolytic potential than NAC-loaded LNPs, which suggests a safer profile of the latter. The in vitro antibiofilm efficacy of the developed formulations was tested against Staphylococcus epidermidis (Gram-positive) and Pseudomonas aeruginosa (Gram-negative) mature biofilms. The results showed that the NAC-loaded LNPs were ineffective against S. epidermidis biofilms, while a significant reduction of biofilm biomass and bacterial viability in P. aeruginosa biofilms were observed. In a more complex therapeutic approach, the LNPs were further combined with moxifloxacin, revealing a beneficial effect between the LNPs and the antibiotic against P. aeruginosa biofilms. Both alone and in combination with moxifloxacin, unloaded and NAC-loaded LNPs functionalized with d-amino acids showed a great potential to reduce bacterial viability, with no significant differences in the presence or absence of NAC. However, the presence of NAC in NAC-loaded functionalized LNPs shows a safer profile than the unloaded LNPs, which is beneficial for an in vivo application. Overall, the developed formulations present a potential therapeutic approach against P. aeruginosa biofilms, alone or in combination with antibiotics.

Polymeric matrix hydrophobicity governs saponin packing-density on nanoparticle surface and the subsequent biological interactions

This study investigated the loading behavior of Quillaja saponin as a model surface-active cargo on (NP) nanoparticles prepared with various hydrophobic polymers and using different organic solvents through emulsification/solvent evaporation, and the impact of NP surface hydrophobicity upon the cytotoxic and hemolytic properties of the loaded entity. A superficial monolayered arrangement of saponins on NP was established (R² > 0.9) for all NP, as the saponin loading values complied with the Langmuir adsorption isotherm over the entire concentration range. Next, based on the measurement of interfacial tension between formulation phases, and the subsequent use of Gibb's adsorption isotherm, the packing density (Г_exc) and loading of saponins on various nanospheres could be predicted with good correlation with the actual values (R² > 0.95). The results demonstrated that the hydrophobicity of the polymeric matrix was the major determinant of saponin packing density on the nanospheres. Finally, the impact of NP surface properties upon saponin biological interactions was investigated, where a linear correlation was found between the NP surface hydrophobicity and their hemolytic properties (R² ≅ 0.79), and cytotoxicity against two cancer cell lines (R² > 0.76). The surface hydrophobicity of the polymeric NP seemingly governed the NP-cell membrane binding, which in turn determined the amount of membrane-bound saponins per unit NP surface area. As the saponins exert their cytotoxicity mainly through strong permeabilization of the cell membrane, a higher amount of NP-membrane association governed by a more hydrophobic matrix can lead to higher levels of cytotoxicity. These findings highlight the importance of a detailed characterization of NP surface properties, particularly in case of surface-active cargos, for these dictate the side effects and biological interactions of the delivery system.

pH-Responsive Micelles From an Oleic Acid Tail and Propionic Acid Heads Dendritic Amphiphile for the Delivery of Antibiotics

The aim of this study was to synthesize a novel biocompatible pH-responsive oleic acid-based dendritic lipid amphiphile (OLA-SPDA) which self-assembled into stable micelles (OLA-SPDA -micelles) with a relatively low critical micelle concentration (CMC) of 5.6 × 10^-6 M. The formulated micelles had particle size, polydispersity index (PDI) and zeta potential (ZP) of 84.16 ± 0.184 nm, 0.199 ± 0.011 and -42.6 ± 1.98 mV, respectively, at pH 7.4. The vancomycin (VCM) encapsulation efficiency was 78.80 ± 3.26%. The micelles demonstrated pH-responsiveness with an increase in particle size to 141.1 ± 0.0707 nm and a much faster release profile at pH 6.0, as compared to pH 7.4. The minimum inhibitory concentration (MIC) of VCM-OLA-SPDA-micelle against methicillin-resistant staphylococcus aureus (MRSA) was 8-fold lower compared to bare VCM, and the formulation had a 4-fold lower MIC at pH 6.0 when compared to the formulation's MIC at pH 7.4. MRSA viability assay showed the micelles had a percentage killing of 93.39% when compared bare-VCM (58.21%) at the same MIC (0.98 μg/mL). In vivo mice (BALB/c) skin infection models showed an 8-fold reduction in MRSA burden after treatment with VCM-OLA-SPDA-micelles when compared with bare VCM. The above results suggest that pH-responsive VCM-OLA-SPDA-micelles has the potential to be an effective carrier to enhance therapeutic outcomes against infections characterised by low pH.

One-year chronic toxicity evaluation of single dose intravenously administered silica nanoparticles in mice and their Ex vivo human hemocompatibility

Chronic toxicity evaluations of nanotechnology-based drugs are essential to support initiation of clinical trials. Ideally such evaluations should address the dosing strategy in human applications and provide sufficient information for long-term usage. Herein, we investigated one-year toxicity of non-surface modified silica nanoparticles (SNPs) with variations in size and porosity (Stöber SNPs 46 ± 4.9 and 432.0 ± 18.7 nm and mesoporous SNPs 466.0 ± 86.0 nm) upon single dose intravenous administration to female and male BALB/c mice (10 animal/sex/group) along with their human blood compatibility. Our evidence of clinical observation and blood parameters showed no significant changes in body weight, cell blood count, nor plasma biomarker indices. No significant changes were noted in post necropsy examination of internal organs and organ-to-body weight ratio. However, microscopic examination revealed significant amount of liver inflammation and aggregates of histocytes with neutrophils within the spleen suggesting an ongoing or resolving injury. The fast accumulation of these plain SNPs in the liver and spleen upon IV administration and the duration needed for their clearance caused these injuries. There were also subtle changes which were attributed to prior infarctions or resolved intravascular thrombosis and included calcifications in pulmonary vessels, focal cardiac fibrosis with calcifications, and focal renal injury. Most of the pathologic lesions were observed when large, non-porous SNPs were administered. Statistically significant chronic toxicity was not observed for the small non-porous particles and for the mesoporous particles. This one-year post-exposure evaluation indicate that female and male BALB/c mice need up to one year to recover from acute tissue toxic effects of silica nanoparticles upon single dose intravenous administration at their 10-day maximum tolerated dose. Further, ex vivo testing with human blood and plasma revealed no hemolysis or complement activation following incubation with these silica nanoparticles. These results can inform the potential utility of silica nanoparticles in biomedical applications such as controlled drug delivery where intravenous injection of the particles is intended.

Location of stimuli-responsive peptide sequences within silk-elastinlike protein-based polymers affects nanostructure assembly and drug-polymer interactions

Silk-elastinlike protein polymers (SELPs) self-assemble into nanostructures when designed with appropriate silk-to-elastin ratios. Here, we investigate the effect of insertion of a matrix metalloproteinase-responsive peptide sequence, GPQGIFGQ, into various locations within the SELP backbone on supramolecular self-assembly. Insertion of the hydrophilic, enzyme-degradable sequence into the elastin repeats allows the formation of dilution-stable nanostructures, while insertion into the hydrophobic silk motifs inhibited self-assembly. The SELP assemblies retained their lower critical solution temperature (LCST) thermal response, allowing up to eightfold volumetric changes due to temperature-induced size change. A model hydrophobic drug was incorporated into SELP nanoassemblies utilising a combination of precipitation, incubation and tangential flow filtration. While the nanoconstructs degraded in response to MMP activity, drug release kinetics was independent of MMP concentration. Drug release modelling suggests that release is driven by rates of water penetration into the SELP nanostructures and drug dissolution. In vitro testing revealed that SELP nanoassemblies reduced the immunotoxic and haemolytic side effects of doxorubicin in human blood while maintaining its cytotoxic activity.

Synthesis, characterization and biocompatibility of polypyrrole/Cu(II) metal-organic framework nanocomposites

The main objective of composite science is to fabricate new materials with desired properties such as high chemical, mechanical, and/or biological performances. In this research, new conductive nanocomposites of copper metal-organic frameworks (Cu-MOF) and polypyrrole (PPy) were fabricated with the aim of exploiting the electrical conductivity of polypyrrole and the porosity of MOFs in the final products. The prepared compounds (PPy/x%Cu-MOF, x = 20, 50, and 80) were investigated by FTIR, PXRD, SEM, TEM, DLS, BET, EDS mapping, cyclic voltammetry (CV), and zeta potential (ξ) measurements. Spherical morphology was confirmed by SEM and TEM analysis. The PPy/80%Cu-MOF nanocomposite showed the highest ξ potential (-40 mV), demonstrating the stability of dispersed particles. The CV results revealed that the nanocomposites have higher capacitance in comparison to the pure materials. In vitro degradation of the as-prepared compounds in simulated body fluid (SBF) was studied by EIS (electrochemical impedance spectroscopy) and Tafel polarization tests. Furthermore, in vitro biocompatibility of the PPy/x%Cu-MOF composite was evaluated on a group of cells including 3T3 fibroblasts, MCF-7 breast cancer cells, J774.A1 macrophages and red blood cells (RBCs). Viability of 3T3 fibroblasts, MCF-7, and J774.A1 cells, by Methylthiazolyldiphenyl-tetrazolium bromide (MTT) method, was dependent on Cu-MOF percent and amount of composites. Hemolytic assay for RBCs exposed to different amounts of the PPy/x%Cu-MOF composites showed hematological toxicity less than 5% in most concentrations. In addition, to investigate pro-inflammatory activity, J774.A1 macrophages were exposed to non-toxic concentrations of the PPy/x%Cu-MOF and no significant change in the expression of two inflammatory genes COX-2 and iNOS was observed. Injection of the PPy/x%Cu-MOF (5 mg kg^-1) into bloodstream of mice did not increase liver damage marker enzymes alanine transaminase (ALT) and aspartate transaminase (AST) level in serum 1 week post injection. Moreover, we observed slight but not significant increase in serum copper level in mice 1 week after injection. According to the results, the PPy/x%Cu-MOF nanocomposites exhibited a good in vitro and in vivo biocompatibility without inducing pro-inflammatory responses in macrophages and show promising potential for different biomedical applications such as biosensors and drug delivery. The release of curcumin from curcumin-loaded PPy/x%Cu-MOF nanocomposites was detectable in plasma of mice 4 days after administration.

Blood-Contacting Biomaterials: In Vitro Evaluation of the Hemocompatibility

Hemocompatibility of blood-contacting biomaterials is one of the most important criteria for their successful in vivo applicability. Thus, extensive in vitro analyses according to ISO 10993-4 are required prior to clinical applications. In this review, we summarize essential aspects regarding the evaluation of the hemocompatibility of biomaterials and the required in vitro analyses for determining the blood compatibility. Static, agitated, or shear flow models are used to perform hemocompatibility studies. Before and after the incubation of the test material with fresh human blood, hemolysis, cell counts, and the activation of platelets, leukocytes, coagulation and complement system are analyzed. Furthermore, the surface of biomaterials are evaluated concerning attachment of blood cells, adsorption of proteins, and generation of thrombus and fibrin networks.

Facile Synthesis of Ligand-Free Iridium Nanoparticles and Their In Vitro Biocompatibility

High-density inorganic nanoparticles have shown promise in medical applications that utilize radiation including X-ray imaging and as radiation dose enhancers for radiotherapy. We have developed an aqueous synthetic method to produce small (~ 2 nm) iridium nanoparticles (IrNPs) by reduction of iridium(III) chloride using a borohydride reducing agent. Unlike other solution-based synthesis methods, uniform and monodispersed IrNPs are produced without the use of surfactants or other solubilizing ligands. These nanoparticles are highly crystalline as observed by X-ray diffraction and high-resolution transmission electron microscopy (TEM). In vitro metabolic toxicity assays using hepatocyte and macrophage cells demonstrate that both IrNPs and iridium(III) chloride are well tolerated at concentrations of up to 10 μM iridium. Furthermore, the IrNPs were assessed in a hemolytic assay and found to have no significant impact on red blood cells when exposed to concentrations up to 100 μM. Overall, these results support the potential for the in vivo application of this nanomaterial.

In Vitro Characterization and Evaluation of the Cytotoxicity Effects of Nisin and Nisin-Loaded PLA-PEG-PLA Nanoparticles on Gastrointestinal (AGS and KYSE-30), Hepatic (HepG2) and Blood (K562) Cancer Cell Lines

The aim of this study was an in vitro evaluation and comparison of the cytotoxic effects of free nisin and nisin-loaded PLA-PEG-PLA nanoparticles on gastrointestinal (AGS and KYSE-30), hepatic (HepG2), and blood (K562) cancer cell lines. To create this novel anti-cancer drug delivery system, the nanoparticles were synthesized and then loaded with nisin. Subsequently, their biocompatibility, ability to enter cells, and physicochemical properties, including formation, size, and shape, were studied using hemolysis, fluorescein isothiocyanate (FITC), Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and scanning electron microscopy (SEM), respectively. Then, its loading efficiency and release kinetics were examined to assess the potential impact of this formulation for the nanoparticle carrier candidacy. The cytotoxicities of nisin and nisin-loaded nanoparticles were evaluated by using the MTT and Neutral Red (NR) uptake assays. Detections of the apoptotic cells were done via Ethidium Bromide (EB)/Acridine Orange (AO) staining. The FTIR spectra, SEM images, and DLS graph confirmed the formations of the nanoparticles and nisin-loaded nanoparticles with spherical, distinct, and smooth surfaces and average sizes of 100 and 200 nm, respectively. The loading efficiency of the latter nanoparticles was about 85-90%. The hemolysis test represented their non-cytotoxicities and the FITC images indicated their entrance inside the cells. An increase in the percentage of apoptotic cells was observed through EB/AO staining. These results demonstrated that nisin had a cytotoxic effect on AGS, KYSE-30, HepG2, and K562 cancer cell lines, while the cytotoxicity of nisin-loaded nanoparticles was more than that of the free nisin.

Updated Method for In Vitro Analysis of Nanoparticle Hemolytic Properties

Hemolysis is damage to red blood cells (RBCs), which results in the release of the iron-containing protein hemoglobin into plasma. An in vitro assay was developed and described earlier for the analysis of nanoparticle hemolytic properties. Herein, we present a revised version of the original protocol. In this protocol, analyte nanoparticles and controls are incubated in blood. Undamaged RBCs are removed by centrifugation and hemoglobin, released by the damaged erythrocytes, is converted to cyanmethemoglobin by incubation with Drabkin's reagent. The amount of cyanmethemoglobin in the supernatant is measured by spectrophotometry. This measured absorbance is compared to a standard curve to determine the concentration of hemoglobin in the supernatant. The measured hemoglobin concentration is then compared to the total hemoglobin concentration to obtain the percentage of nanoparticle-induced hemolysis. The revision includes updated details about nanoparticle sample preparation, selection of nanoparticle concentration for the in vitro study, updated details about assay controls and case studies about nanoparticle interference with the in vitro hemolysis assay.

Hematological Effects of Gold Nanorods on Erythrocytes: Hemolysis and Hemoglobin Conformational and Functional Changes

Gold nanorods (GNRs) are a unique class of metal nanostructures that have attractive potentials in biomedical applications, and the concern on their biological safety is concomitantly increasing. Hemocompatibility is extremely important as their contact with blood circulation is unavoidable during in vivo delivery. Herein, two kinds of GNRs coated with hexadecyltrimethylammonium bromide (C-GNRs) or poly(sodium-p-styrenesulfonate) are used to test their potential toxicological effects in blood. C-GNRs with positive surface charges efficiently induce hemolysis when encountering erythrocytes. Cellular internalization of C-GNRs is found, and they subsequently bind with hemoglobin, forming bioconjugates. The interaction between hemoglobin and C-GNR (stoichiometry 32.7:1) is regulated by electrostatic forces. Chromophores like tryptophan (Trp) are found to interact with C-GNRs, causing enhancement in fluorescence intensity. The conformation of protein is partially altered, evidenced by decrease in α-helical, increase in β-sheet and random coil of hemoglobin. Although C-GNRs do not essentially decrease oxygen binding capacity of hemoglobin, they hamper oxygen release from the protein. Heme, the oxygen binding unit, releases from hemoglobin upon C-GNR treatment, which could contribute to C-GNR-induced hemolysis. This study demonstrates the hematological effects of GNRs, revealing their potential risk in biomedical applications.

Flow cytometric analysis of the physical and protein-binding characteristics of solid drug nanoparticle suspensions

Aim: Oral and intramuscular sustained-release antiretroviral solid drug nanoparticles (SDNs) are in development but there is limited understanding of whether nanoparticles or dissolved drug predominate systemically. Materials & methods: A flow cytometric method was developed to analyze SDNs in biological fluids such as plasma, including the putative formation of a protein corona. Results: SDNs were found to be stable in plasma and could be observed using the techniques developed here. In addition, transferrin, fibrinogen and albumin were found to be associated with SDNs upon incubation. Conclusion: This methodology has enabled us to determine protein interactions of SDNs in solution without the requirement of separation from the matrix. This will enable further studies of their biological fate.

Original submitted 12 February 2014; Revised submitted 10 April 2014

Polymeric micelles for enhanced Photofrin II ® delivery, cytotoxicity and pro-apoptotic activity in human breast and ovarian cancer cells

BACKGROUND

Searching for photodynamic therapy (PDT) - effective nanocarriers which enable a photosensitizer to be selectively delivered to tumor cells with enhanced bioavailability and diminished dark cytotoxicity is of current interest. The main objective of this study is to evaluate newly designed mixed polymeric micelles based on Pluronics P123 and F127 for the improved delivery of Photofrin II(®) (Ph II(®)) to circumvent unfavorable effects overcoming multidrug resistance (MDR) in tumor cells - in breast MCF-7/WT (caspase-3 deficient) and ovarian SKOV-3 (resistant to chemotherapy).

METHODS

Ph II(®)-loaded micelles were obtained and analyzed for size and morphology, solubilization efficiency, physical stability and in vitro drug release. Intracellular uptake, reactive oxygen species (ROS) generation, mitochondrial oxidoreductive potential and proapoptotic activity (TUNEL assay) studies were evaluated in the examined cancer cells. The preliminary biocompatibility characteristics of all nanocarriers was determined by assessment of their hemolytic activity in human erythrocytes and dark toxicity in cancer cells.

RESULTS

Dynamic light scattering (DLS) and atomic force microscopy (AFM) confirmed that almost monodisperse, sphere-shaped and nanosized (DH<20 nm) carriers were developed. Biological studies after photodynamic reaction (PDR) with encapsulated Ph II(®) revealed increased ROS level, malondialdehyde (MDA) concentration and protein damage in SKOV-3 and MCF-7/WT cells in comparison to treatment with free Ph II(®). Numerous apoptotic cells were detected after nano-therapy in both cell lines, with observed significant morphological disorders in ovarian cancer cells. In the case of encapsulated Ph II(®) only negligible disruption of human erythrocytes and cancer cells was observed.

CONCLUSIONS

The obtained biocompatible long-lasting nanocarriers significantly enhance the Photofrin II(®) photodynamic effect and apoptosis in both SKOV-3 and MCF-7/WT cell lines.

Safety of the intravenous administration of neurotensin-polyplex nanoparticles in BALB/c mice

Neurotensin (NTS)-polyplex is a gene nanocarrier that has potential nanomedicine-based applications for the treatment of Parkinson's disease and cancers of cells expressing NTS receptor type 1. We assessed the acute inflammatory response to NTS-polyplex carrying a reporter gene in BALB/c mice. The intravenous injection of NTS-polyplex caused the specific expression of the reporter gene in gastrointestinal cells. Six hours after an intravenous injection of propidium iodide labeled-NTS-polyplex, fluorescent spots were located in the cells of the organs with a mononuclear phagocyte system, suggesting NTS-polyplex clearance. In contrast to lipopolysaccharide and carbon tetrachloride, NTS-polyplex did not increase the serum levels of tumor necrosis factor alpha, interleukin (IL)-1β, IL-6, bilirubin, aspartate transaminase, and alanine transaminase. NTS-polyplex increased the levels of serum amyloid A and alkaline phosphatase, but these levels normalized after 24 h. Compared to carrageenan, the local injection of NTS-polyplex did not produce inflammation. Our results support the safety of NTS-polyplex.

FROM THE CLINICAL EDITOR

This study focuses on the safety of neurotensin (NTS)-polyplex, a gene nanocarrier that has potential in the treatment of Parkinson's disease and cancers of cells expressing NTS receptor type 1. NTS polyplex demonstrates a better safety profile compared with carrageenan, lipopolysaccharide, and carbon tetrachloride in a murine model.

Hemotoxicity of carbon nanotubes

Carbon nanotubes may enter into the bloodstream and interact with blood components indirectly via translocation following unintended exposure or directly after an intended administration for biomedical purposes. Once introduced into systemic circulation, nanotubes will encounter various proteins, biomolecules or cells which have specific roles in the homeostasis of the circulatory system. It is therefore essential to determine whether those interactions will lead to adverse effects or not. Advances in the understanding of how carbon nanotubes interact with blood proteins, the complement system, red blood cells and the hemostatic system are reviewed in this article. While many studies on carbon nanotube health risk assessment and their biomedical applications have appeared in the last few years, reports on the hemocompatibility of these nanomaterials remain surprisingly limited. Yet, defining the hemotoxicological profile is a mandatory step toward the development of clinically-relevant medications or contrast agents based on carbon nanotubes.

In vivo safety evaluation of polyarginine coated magnetic nanovectors

Safety and efficacy are of critical importance to any nanomaterial-based diagnostic and therapy. The innocuity and functionality of a nanomaterial in vivo is largely dependent on the physicochemical properties of the material, particularly its surface coating. Here, we evaluated the influence of polycationic coating on the efficacy, clearance organ uptake, and safety of magnetic nanovectors designed for siRNA delivery. Polyethylene glycol (PEG) coated superparamagnetic iron oxide nanoparticles (NPs) of 12 nm in core diameter were modified with a polycationic coating of either poly-l-arginine (pArg) or polyethylenimine (PEI) and further covalently functionalized with siRNA oligonucleotides. The produced NP-pArg-siRNA and NP-PEI-siRNA nanovectors were similar in hydrodynamic size (21 and 22 nm, respectively) but significantly differed in zeta potentials (+2.1 mV and +29.8 mV, respectively). Fluorescence quantification assays revealed that the NP-pArg-siRNA nanovector was 3-fold more potent than NP-PEI-siRNA in delivering siRNA and 1.8-fold more effective in gene silencing when tested in rat C6 glioblastoma cells. In vivo, both nanovector formulations were similarly taken up by the spleen and liver as determined by histopathological and hemopathological assays. However, PEI coated nanovectors elicited severe hemoincompatibility and damage to the liver and spleen, while pArg coated nanovectors were found to be safe and tolerable. Combined, our findings suggest that polycationic coatings of pArg were more effective and safer than commonly used PEI coatings for preparation of nanovectors. The NP-pArg-siRNA nanovector formulation developed here shows great potential for in vivo based biomedical applications.