Kupffer Cells Regulate Natural Killer Cells Via the NK group 2, Member D (NKG2D)/Retinoic Acid Early Inducible-1 (RAE-1) Interaction and Cytokines in a Primary Biliary Cholangitis Mouse Model.

BACKGROUND Kupffer cells and natural killer (NK) cells has been identified as contributing factors in the pathogenesis of hepatitis, but the detailed mechanism of these cell types in the pathogenesis of primary biliary cholangitis (PBC) is poorly understood. MATERIAL AND METHODS In this study, polyinosinic: polycytidylic acid (poly I: C), 2-octynoic acid-bovine serum albumin (2OA-BSA) and Freund's adjuvant (FA) were injected to establish a murine PBC model, from which NK cells and Kupffer cells were extracted and isolated. The cells were then co-cultivated in a designed culture system, and then NK group 2, member D (NKG2D), retinoic acid early inducible-1 (RAE-1), F4/80, and cytokine expression levels were detected. RESULTS The results showed close crosstalk between Kupffer cells and NK cells. PBC mice showed increased surface RAE-1 protein expression and Kupffer cell cytokine secretion, which subsequently activated NK cell-mediated target cell killing via NKG2D/RAE-1 recognition, and increased inflammation. NK cell-derived interferon-γ (IFN-γ) and Kupffer cell-derived tumor necrosis factor alpha (TNF-alpha) were found to synergistically regulate inflammation. Moreover, interleukin (IL)-12 and IL-10 improved the crosstalk between NK cells and Kupffer cells. CONCLUSIONS Our findings in mice are the first to suggest the involvement of the NKG2D/RAE-1 interaction and cytokines in the synergistic effects of NK and Kupffer cells in PBC.

Palbociclib: A breakthrough in breast carcinoma in women.

Breast cancer (BC) is the most common cancer and leading cause of death in women worldwide. Cellular proliferation, growth, and division are tightly controlled by the cell-cycle regulatory machinery. An important pathway is cyclin-dependent kinases (CDKs) which regulate cell cycle and thus control transcriptional processes. In human cancer, multiple CDK family members are commonly deregulated. The cyclin D-CDK4/6-retinoblastoma (RB) protein-INK4 axis is particularly affected in many solid tumors which leads to cancer cell proliferation. This has led to long-standing interest in targeting CDK4/6 as an anticancer strategy. Different investigational agents that have been tested which inhibit multiple cell cycle and transcriptional CDKs but have carried excessive toxicity thus failed to stand the rational of human use. Amongst several selective and potent inhibitors of CDK4/6, palbociclib is the first to be accessed suitable for human use having explicit selectivity toward CDK4/6. Its mechanism is to arrest cells in G1 phase by blocking RB phosphorylation at CDK4/6-specfic sites without affecting the growth of cells which are RB-deficient. Studies conducted in patients of BC having cells with advanced RB-expression demonstrated acceptable side effects but dose-limiting toxicities primarily neutropenia and thrombocytopenia, with prolonged stable disease in patients.

Simple and sensitive electrochemical impedimetric approach towards analysis of biophysical interaction.

Study of biophysical interactions have been carried out using specific combination of proteins such as human IgG (as antigen) and anti-human IgG (as complementary antibody; raised in rabbit). Bovine serum albumin (BSA) was used to block any nonspecific interaction between antigen and antibody as BSA has been reported to bind to several sites non-specifically. Optimization of BSA concentration was done in order to make the antigen-antibody interaction relatively more pronounced and specific. We have used gold electrode in order to provide a relatively inert platform for adsorption/immobilization of protein molecules. The interaction between the antigen and antibody caused an increase in the charge transfer resistance (parallel resistance in Randles cell model) for an indicator molecule (hexacyanoferrate) and this was monitored by impedance spectroscopy. Detection limit for the antigen was found to be about 50 ng/mL. The approach presented is general and versatile and can be used for any antigen-antibody pair without any significant modification.

Real-World Assessment of Personalized Approach With Voglibose Fixed-Dose Combination in Type 2 Diabetes Mellitus.

BACKGROUND: Post-prandial hyperglycemia (PPHG) remains a complex aspect in the management of type 2 diabetes mellitus (T2DM) in the Indian population due to uncertainty in the optimal utilization of alpha-glucosidase inhibitors (AGIs) either as standalone therapy or in combination, whether initiated initially or as a sequential therapy. METHODS: This was a post-approval, observational, multicentric clinical study conducted at 50 centers according to principles of the International Council for Harmonisation of Technical Requirements of Pharmaceuticals for Human Use Guideline for Good Clinical Practice (ICH-GCP) and Declaration of Helsinki and local ethics approval. Descriptive and analytical statistics were applied for conclusion and categorical variables using SPSS version 29.0.1.0 (171) (Armonk, NY: IBM Corp.). RESULTS: Protocol analyses of 515 cases revealed baseline demographics as follows: age 57.35±10.04 years, weight 72.86±10.92 kg, and BMI 28.33±6.07 kg/m2. Comorbidities included hypertension (N=169, 32.82%), thyroid disorders (N=99, 19.22%), and heart failure (N=92, 17.86%). Concomitant oral antidiabetics (OADs) prescribed as DPP4i (9.50%), SGLT2i (19.20%), and DPP4i+SGLT2i (7.20%). Study drug reduced glycosylated hemoglobin (HbA1c) by 13.77% (1.25% mean change, p<0.01), fasting blood glucose (FBG) by 23.69% (44.61 mg/dL mean change, p<0.01), post-prandial blood glucose (PPBG) by 24.57% (70.46 mg/dL mean change, p<0.01), and body weight by 4.43% (3.21 kg mean change, p<0.01) over 12 weeks. A total of 161 patients accomplished targeted PPBG of <180 mg/dL (119.13 mg/dL mean change, p<0.01). Regression analysis considering PPBG and HbA1c ≤7.5% showed a weak correlation between them (R-value=0.13, R-squared value=0.02), whereas between PPBG and HbA1c ≤9% yielded moderate positive correlation (R-value=0.53, R-squared value=0.28). There were no adverse events reported or analyzed during the observation period. CONCLUSION: Voglibose fixed-dose combination (FDC) demonstrates significant effectiveness at the initial dosage when started early in the management of T2DM and high PPBG levels. Moreover, it exhibits good tolerability, thereby contributing to higher compliance among Indian patients who consume a high-carbohydrate diet.

Investigating the phenology and interactions of competitive plant species co-occurring with invasive Lantana camara in Indian Himalayan Region.

Invasive plant species are considered one of the significant drivers of habitat loss, leading to biodiversity loss. They have also been observed to alter the local ecology, resulting in a decline of native flora. The management of invasive species is widely recognised as one of the most severe challenges to biodiversity conservation. The International Union for Conservation of Nature (IUCN) considers Lantana camara, as one of the ten worst weeds. Over time, native and indigenous species may evolve to co-exist or compete with invasive species, reducing invader fitness. It is observed that species competition fluctuates throughout environmental gradients, life phases, and abundances. Hence, competition outcome is very context-dependent. To address this challenge, we conducted a comprehensive study in three phases: we identified native species coexisting with Lantana in their natural habitats in the Doon Valley (Phase I) and documented the phenotypic traits of selected coexisting species using the Landmark BBCH (Biologische Bun-desantalt, Bundessortenamt und Chemische Industrie) scale, revealing the phenological growth patterns of selected co-existing species (Phase II). This was followed by conducting pot (Phase IIIa) and field (Phase IIIb) experiments to study the interactions between them. Notably, Justicia adhatoda, Broussonetia papyrifera, Pongamia pinnata, Urtica dioica and Bauhinia variegata demonstrated promising results in both pot and field conditions. Furthermore, after the mechanical removal of Lantana and prior to the plantation in the field experiments, four native grass species were introduced using the seed ball method. Among these, Pennisetum pedicellatum and Sorghum halpense exhibited prompt regeneration and effectively colonised the field, densely covering the cleared area. The study provides a comprehensive management plan for the restoration of Lantana affected areas through competition using native species. This study utilizes phenological assessment for native plant selection using reclamation from native grasses and proposes a management plan for combating invasive Lantana.

Biochar application for greenhouse gas mitigation, contaminants immobilization and soil fertility enhancement: A state-of-the-art review.

Rising global temperature, pollution load, and energy crises are serious problems, recently facing the world. Scientists around the world are ambitious to find eco-friendly and cost-effective routes for resolving these problems. Biochar has emerged as an agent for environmental remediation and has proven to be the effective sorbent to inorganic and organic pollutants in water and soil. Endowed with unique attributes such as porous structure, larger specific surface area (SSA), abundant surface functional groups, better cation exchange capacity (CEC), strong adsorption capacity, high environmental stability, embedded minerals, and micronutrients, biochar is presented as a promising material for environmental management, reduction in greenhouse gases (GHGs) emissions, soil management, and soil fertility enhancement. Therefore, the current review covers the influence of key factors (pyrolysis temperature, retention time, gas flow rate, and reactor design) on the production yield and property of biochar. Furthermore, this review emphasizes the diverse application of biochar such as waste management, construction material, adsorptive removal of petroleum and oil from aqueous media, immobilization of contaminants, carbon sequestration, and their role in climate change mitigation, soil conditioner, along with opportunities and challenges. Finally, this review discusses the evaluation of biochar standardization by different international agencies and their economic perspective.

The Clostridium Metabolite P-Cresol Sulfate Relieves Inflammation of Primary Biliary Cholangitis by Regulating Kupffer Cells.

OBJECTIVE: To study the effect and mechanism of the Clostridium metabolite p-Cresol sulfate (PCS) in primary biliary cholangitis (PBC). METHODS: Gas chromatography-mass spectrometry (GC-MS) was used to detect differences in tyrosine, phenylalanine, tryptophan, PCS, and p-Cresyl glucuronide (PCG) between the serum of PBC patients and healthy controls. In vivo experiments, mice were divided into the normal control, PBC group, and PBC tyrosine group. GC-MS was used to detect PCS and PCG. Serum and liver inflammatory factors were compared between groups along with the polarization of liver Kupffer cells. Additionally, PCS was cultured with normal bile duct epithelial cells and Kupffer cells, respectively. PCS-stimulated Kupffer cells were co-cultured with lipopolysaccharide-injured bile duct epithelial cells to detect changes in inflammatory factors. RESULTS: Levels of tyrosine and phenylalanine were increased, but PCS level was reduced in PBC patients, with PCG showing a lower concentration distribution in both groups. PCS in PBC mice was also lower than those in normal control mice. After oral administration of tyrosine feed to PBC mice, PCS increased, liver inflammatory factors were decreased, and anti-inflammatory factors were increased. Furthermore, Kupffer cells in the liver polarized form M1 transitioned to M2. PCS can damage normal bile duct epithelial cells and suppress the immune response of Kupffer cells. But PCS protects bile duct epithelial cells damaged by LPS through Kupffer cells. CONCLUSIONS: PCS produced by Clostridium-metabolized tyrosine reduced PBC inflammation, suggesting that intervention by food, or supplementation with PCS might represent an effective clinical strategy for treating PBC.

Design and In-silico study of bioimaging fluorescence Graphene quantum dot-Bovine serum albumin complex synthesized by diimide-activated amidation.

Graphene quantum dot possesses advantageous characteristics like tunable fluorescence, nanometer size, low cytotoxicity, high biocompatibility enabling them as an ideal material for fluorescence bio-imaging. It exhibits a unique characteristic of DNA cleavage activity enhancer, gene/drug carrier, and anticancer targeting applications. In this article, we discussed the preparation of graphene quantum dot through the bottom-up method. Carbodiimide-activated amidation reactions were used for the functionalization of graphene quantum dot with Bovine Serum Albumin. Fluorescence spectroscopy data showed that the graphene quantum dot has size-dependent fluorescence emission. TEM and AFM studies showed that the size of graphene quantum dot was around 20 nm with narrow size distribution. Carbodiimide-activated amidation conjugation was successful in binding the protein onto graphene quantum dot and these conjugates were characterized by DLS, FTIR, fluorescence spectroscopy, and agarose gel electrophoresis. We also studied the structural-based in-silico molecular dynamic simulation by AutoDock, PyRx, and Discovery Studio Visualizer. Based on the virtual screening analysis and higher negative energy incorporation, it is observed that graphene quantum dot conjugated with bovine serum albumin quickly and formed is highly stable complex, which makes them a potential candidate for future applications in the field of bio-imaging, bio-sensing, gene/drug delivery, and tumor theragnostic.

Biclonal gammopathay in a case of severe COVID-19.

COVID-19 is a disease caused by a coronavirus named as SARS-CoV-2. It has become pandemic due to its contagious nature. Majority of the patients are asymptomatic or having mild flu like symptoms. Few need hospitalisation due to severe acute respiratory infection (SARI). Co-morbidity like diabetes, hypertension, renal failure etc. are associated with severe COVID-19 that often causes death. There have been only two published case reports of monoclonal gammopathy of unknown significance (MGUS) in patients with COVID-19 disease. Cytokine storm is often observed in severe COVID-19 and various cytokines including IL-6 that activates plasma cells are increased in blood in this condition. Here we present a case of severe COVID-19 patient with bioclonal gammopathy. He was known diabetic and hypertensive on treatment. He developed SARI, cytokines storm and septicaemia, treated with antibiotics, enoxaparin, hydroxychloroquine, insulin, anti-hypertensives, put on ventilator, subsequently developed septicaemia, multi-organ failure and died. Two M-bands on serum capillary electrophoresis with presence IgG-κ on both the M-bands indicates a biclonal gammopathy of unknown significance in this patient. We conclude that like MGUS, early stage biclonal gammopathy, although rare, gets manifested with M-bands on plasma protein electrophoresis. It is probably due to high level of IL-6 associated with cytokine storm in severe COVID-19 that stimulate early stage dyscratic plasma cells. Such biclonal gammopathy might be a risk factor for severe COVID-19 and associated mortality.

Concomitant methicillin-resistant Staphylococcus aureus infection in tubercular sacroiliitis masquerading as anti-tubercular drug resistance: Role for molecular diagnosis.

A 23-year-old female on anti-tubercular therapy for tuberculous sacroiliitis presented with right sided gluteal and thigh abscess. Suspecting treatment failure, surgical evacuation of purulent material was done. The bacteriological isolation showed positivity for methicillin-resistant Staphylococcus aureus. Although the microbiological and histopathology examination of the specimen were negative for tubercular isolates, the cartridge based -nucleic acid amplification tests revealed positive genes for Mycobacterium tuberculosis and additional primers showed sensitivity for rifampicin and isoniazid. She was adequately treated with vancomycin for six weeks and anti-tubercular drugs for eight months and followed till the bony ankyloses at 18 months. This is a rare case based scenario wherein concomitant staphylococcal infection in tubercular sacroiliitis masqueraded as anti-tubercular drug resistance. The cartridge-based nucleic acid amplification test for tuberculosis is a rapid and sensitive modality in identifying mycobacteria even mixed infections and also determine drug resistance. There are fewer consensuses in the literature regarding the drugs and duration of anti-tubercular regime for tuberculous sacroiliitis with most regimes using four drugs between six to eighteen months.

Synthesis and surface engineering of iron oxide nanoparticles for biomedical applications.

Superparamagnetic iron oxide nanoparticles (SPION) with appropriate surface chemistry have been widely used experimentally for numerous in vivo applications such as magnetic resonance imaging contrast enhancement, tissue repair, immunoassay, detoxification of biological fluids, hyperthermia, drug delivery and in cell separation, etc. All these biomedical and bioengineering applications require that these nanoparticles have high magnetization values and size smaller than 100 nm with overall narrow particle size distribution, so that the particles have uniform physical and chemical properties. In addition, these applications need special surface coating of the magnetic particles, which has to be not only non-toxic and biocompatible but also allow a targetable delivery with particle localization in a specific area. To this end, most work in this field has been done in improving the biocompatibility of the materials, but only a few scientific investigations and developments have been carried out in improving the quality of magnetic particles, their size distribution, their shape and surface in addition to characterizing them to get a protocol for the quality control of these particles. Nature of surface coatings and their subsequent geometric arrangement on the nanoparticles determine not only the overall size of the colloid but also play a significant role in biokinetics and biodistribution of nanoparticles in the body. The types of specific coating, or derivatization, for these nanoparticles depend on the end application and should be chosen by keeping a particular application in mind, whether it be aimed at inflammation response or anti-cancer agents. Magnetic nanoparticles can bind to drugs, proteins, enzymes, antibodies, or nucleotides and can be directed to an organ, tissue, or tumour using an external magnetic field or can be heated in alternating magnetic fields for use in hyperthermia. This review discusses the synthetic chemistry, fluid stabilization and surface modification of superparamagnetic iron oxide nanoparticles, as well as their use for above biomedical applications.

Cytotoxicity suppression and cellular uptake enhancement of surface modified magnetic nanoparticles.

The aim of this study was to modify the surfaces of superparamagnetic iron oxide nanoparticles (SPION) with pullulan in order to reduce the cytotoxicity and enhance the cellular uptake of the nanoparticles. In this study, we have prepared and characterised the pullulan coated superparamagnetic iron oxide nanoparticles (Pn-SPION) of size around 40-45 nm with magnetite inner core and hydrophilic outer shell of pullulan. We have investigated the effect of cellular uptake of uncoated and Pn-SPION on cell adhesion/viability, cytotoxicity, morphology and cytoskeleton organisation of human fibroblasts. Cell cytotoxicity/adhesion studies of SPIONs on human dermal fibroblasts showed that the particles are toxic and their internalisation resulted in disruption of cytoskeleton organisation of cells. On the other hand, Pn-SPIONs were found to be non-toxic and induced changes in cytoskeleton organisation different from that observed with SPION. Transmission electron microscopy results indicated that the SPION and Pn-SPION were internalised into cells via different mechanisms, thereby suggesting that the particle endocytosis behaviour is dependent on the surface characteristics of the nanoparticles.

Naloxegol: First oral peripherally acting mu opioid receptor antagonists for opioid-induced constipation.

Opioid-induced constipation (OIC) is one of the most troublesome and the most common effects of opioid use leading to deterioration in quality of life of the patients and also has potentially deleterious repercussions on adherence and compliance to opioid therapy. With the current guidelines advocating liberal use of opioids by physicians even for non-cancer chronic pain, the situation is further complicated as these individuals are not undergoing palliative care and hence there cannot be any justification to subject these patients to the severe constipation brought on by opioid therapy which is no less debilitating than the chronic pain. The aim in these patients is to prevent the opioid-induced constipation but at the same time allow the analgesic activity of opioids. Many drugs have been used with limited success but the most specific among them were the peripherally acting mu opioid receptor antagonists (PAMORA). Methylnaltrexone and alvimopan were the early drugs in this group but were not approved for oral use in OIC. However naloxegol, the latest PAMORA has been very recently approved as the first oral drug for OIC. This article gives an overview of OIC, its current management and more specifically the development and approval of naloxegol, including pharmacokinetics, details of various clinical trials, adverse effects and its current status for the management of OIC.

Lactoferrin and ceruloplasmin derivatized superparamagnetic iron oxide nanoparticles for targeting cell surface receptors.

Tissue and cell-specific drug targeting can be achieved by employing nanoparticle coatings or carrier-drug conjugates that contain a ligand recognized by a receptor on the target cell. Superparamagnetic iron oxide nanoparticles have been used for many years in various biomedical applications. In this study, superparamagnetic nanoparticles with specific shape and size have been prepared and coupled to various proteins. These particles are characterized in vitro and their influence on human dermal fibroblasts is assessed in terms of cell adhesion, viability, morphology and cytoskeleton organization using various techniques to observe cell-nanoparticle interaction, including light, fluorescence, scanning and transmission electron microscopy. The results showed that each nanoparticle type with different surface characteristics caused a distinctly different cell response. The underivatized magnetic particles were internalized by the fibroblasts probably due to endocytosis, which resulted in disruption of the cell membrane and disorganized cell cytoskeleton. In contradiction, lactoferrin or ceruloplasmin coated nanoparticles attached to the cell membrane, most likely to the cell expressed receptors and were not endocytosed. One major problem with uncoated magnetic nanoparticles has been the endocytosis of particles leading to irreversible entry. These experiments provide a route to prevent this problem, suggesting that cell response can be directed via specifically engineered particle surfaces.

Hydrogel pullulan nanoparticles encapsulating pBUDLacZ plasmid as an efficient gene delivery carrier.

This study provides a method for enhancing the delivery of nucleic acid molecules to cells by encapsulating it inside the hydrogel pullulan nanoparticles. In this study, pullulan nanoparticles encapsulating pBUDLacZ plasmid has been prepared inside the aqueous droplets of w/o microemulsions. Transmission electron microscopy (TEM) image showed that the particles are spherical in shape with size of 45+/-0.80 nm diameter. Cell cytotoxicity studies as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay demonstrated that cells incubated with nanoparticles remained more than 100% viable at nanoparticle concentration as high as 1000 microg/ml. From scanning electron microscope images, it was observed that the nanoparticles were internalised and the cells exhibited vacuoles in the cell body due to nanoparticle internalisation. Endocytosis of nanoparticles resulted in disruption of F-actin and beta-tubulin cytoskeleton of human fibroblasts. The efficacy of transfection in vitro on HEK293 and COS-7 cells demonstrated cell type dependence, with COS cells having a higher gene expression. The beta-gal expression in COS-7 cells by pullulan nanoparticle was comparable to commercially available Lipofectamine 2000. The results of this study are encouraging for the development of pullulan nanoparticles as an intracellular delivery system for drugs and genes.

Effect of cellular uptake of gelatin nanoparticles on adhesion, morphology and cytoskeleton organisation of human fibroblasts.

The aim of present study was to prepare nanometer sized particles of gelatin via water-in-oil microemulsion system for drug and gene delivery applications. In this study, cross-linked gelatin nanoparticles encapsulating a fluorescent marker molecule fluorescein isothiocyanate-dextran (FITC-Dex, Mol. Wt. 19.3kDa) have been prepared, characterized and their influence on human fibroblasts has been assessed in terms of cell adhesion, cytotoxicity, light microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and observation of cytoskeleton organisation. Gelatin nanoparticles were prepared inside the aqueous cores of sodium bis(2-ethylhexyl) sulfosuccinate (AOT)/n-hexane reverse micelles. Transmission electron microscopy image showed that the particles are spherical in shape with size of 37+/-0.84 nm diameter. The release of FITC-Dex from the nanoparticles in phosphate buffer saline (pH 7.4) is found to increase with time and about 80% of the encapsulated dye is released in 6 h. Cell adhesion studies with human fibroblasts have shown that gelatin nanoparticles do not affect the number of cells adhered to glass as compared to control cells with no particles. Standard cell viability assay demonstrated that cells incubated with gelatin nanoparticles remained more than 100% viable at concentration as high as 500 microg/ml. From SEM image, it was observed that the nanoparticles were internalised and the fibroblasts exhibited vacuoles in the cell body with cell membrane abnormalities. Endocytosis of nanoparticles was confirmed from TEM studies and it resulted in disruption of F-actin and beta-tubulin cytoskeleton. These studies show that the gelatin nanoparticles prepared by water-in-oil microemulsion systems are endocytosed by the fibroblasts without being toxic to cells even at high concentration of nanoparticles.

Surface-modified superparamagnetic nanoparticles for drug delivery: preparation, characterization, and cytotoxicity studies.

Superparamagnetic iron oxide nanoparticles have been used for many years as magnetic resonance imaging (MRI) contrast agents or in drug delivery applications. In this study, a novel approach to prepare magnetic polymeric nanoparticles with magnetic core and polymeric shell using inverse microemulsion polymerization process is reported. Poly(ethyleneglycol) (PEG)-modified superparamagnetic iron oxide nanoparticles with specific shape and size have been prepared inside the aqueous cores of AOT/n-Hexane reverse micelles and characterized by various physicochemical means such as transmission electron microscopy (TEM), infrared spectroscopy, atomic force microscopy (AFM), vibrating sample magnetometry (VSM), and ultraviolet/visible spectroscopy. The inverse microemulsion polymerization of a polymerizable derivative of PEG and a cross-linking agent resulted in a stable hydrophilic polymeric shell of the nanoparticles. The results taken together from TEM and AFM studies showed that the particles are spherical in shape with core-shell structure. The average size of the PEG-modified nanoparticles was found to be around 40-50 nm with narrow size distribution. The magnetic measurement studies revealed the superparamagnetic behavior of the nanoparticles with saturation magnetization values between 45-50 electromagnetic units per gram. The cytotoxicity profile of the nanoparticles on human dermal fibroblasts as measured by standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that the particles are nontoxic and may be useful for various in vivo and in vitro biomedical applications.

Receptor-mediated targeting of magnetic nanoparticles using insulin as a surface ligand to prevent endocytosis.

Superparamagnetic iron oxide nanoparticles have been used for many years as magnetic resonance imaging contrast agents or in drug delivery applications. Tissue and cell-specific drug targeting by these nanoparticles can be achieved by employing nanoparticle coatings or carrier-drug conjugates that contain a ligand recognized by a receptor on the target cell. In this study, superparamagnetic iron oxide nanoparticles with specific shape and size have been prepared and coupled to insulin for their targeting to cell expressed surface receptors and thereby preventing the endocytosis. The influence of these nanoparticles on human fibroblasts is studied using various techniques to observe cell-nanoparticle interaction that includes light, scanning, and transmission electron microscopy studies. The derivatization of the nanoparticle surface with insulin-induced alterations in cell behavior that were distinct from the underivatized nanoparticles suggests that cell response can be directed via specifically engineered particle surfaces. The results from cell culture studies showed that the uncoated particles were internalized by the fibroblasts due to endocytosis, which resulted in disruption of the cell membrane. In contradiction, insulin-coated nanoparticles attached to the cell membrane, most likely to the cell-expressed surface receptors, and were not endocytosed. The presence of insulin on the surface of the nanoparticles caused an apparent increase in cell proliferation and viability. One major problem with uncoated nanoparticles has been the endocytosis of particles leading to irreversible entry. These results provide a route to prevent this problem. The derivatized nanoparticles show high affinity for cell membrane and opens up new opportunities for magnetic cell separation and recovery that may be of crucial interest for the development of cellular therapies.

In vitro cytotoxicity studies of hydrogel pullulan nanoparticles prepared by AOT/N-hexane micellar system.

PURPOSE: The purpose of this study was to prepare crosslinked pullulan nanoparticles encapsulating bioactive molecules inside the aqueous core of Aerosol-OT/n-hexane reverse micellar droplets with narrow size distribution for drug and gene delivery applications. METHODS: The nanoparticles have been characterised by various physico-chemical methods such as dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), loading capacity and in vitro release behaviour in aqueous buffer. The influence of these nanoparticles on human dermal fibroblasts in vitro has been assessed in terms of cell adhesion, cytotoxicity and light microscopy. RESULTS: Size distribution studies using DLS and TEM show that the particles are spherical in shape with size of 42.0+/-2.5 nm diameter. Release of FITC-Dex from nanoparticles increased with time with 75% of dye released in 6 hours, while only 40% of the dye was released in the initial 2 hours. Results from cell adhesion/viability assay suggest that the pullulan nanoparticles are non-toxic to cells and do not cause any distinct harm to cells. Fibroblasts were healthy and maintained their morphology and adhesion capacity. CONCLUSIONS: These studies indicated that these nanoparticles have further merit as possible carriers for genes and nucleotide drugs for intracellular delivery.