http://www.jnanobiotechnology.com The latest research articles published by Journal of Nanobiotechnology 2010-08-23T00:00:00Z This is an RSS newsfeed from BioMed Central It is intended to be used with an RSS reader. For more information about RSS newsfeeds from BioMed Central, visit http://www.biomedcentral.com/info/about/rss/ Background: Bio-conjugated nanoparticles are important analytical tools with emerging biological and medical applications. In this context in situ conjugation of nanoparticles with biomolecules via laser ablation in aqueous media is a highly promising one step method for the production of functional nanoparticles resulting in high conjugation efficiencies. Increased yields are required particularly considering the conjugation of cost intensive biomolecules like RNA aptamers. Results: Using a DNA aptamer directed against streptavidin in situ conjugation results in nanoparticles with diameters of approximately 9 nm exhibiting a high surface density of aptamers (98 aptamers per nanoparticle) and a maximal conjugation efficiency of 40.3%. We have demonstrated the functionality of the aptamer-conjugated nanoparticles in three independent analytical methods including an agglomeration-based colorimetric assay and solid-phase assays proving high aptamer activity. To demonstrate the general applicability of the in situ conjugation of gold nanoparticles with aptamers we have transferred the approach to a RNA aptamer directed against prostate specific membrane antigen (PSMA). Successful detection of PSMA in human prostate cancer tissue was achieved utilizing tissue microarrays. Conclusions: In comparison to conventional generation of bio-conjugated gold nanoparticles by chemical synthesis and subsequent bio-functionalization, the laser ablation-based in situ conjugation allows the rapid one-step production. Due to high conjugation efficiency and productivity in situ conjugation can be easily used for high throughput generation of gold nanoparticles conjugated with precious biomolecules like aptamers. http://www.jnanobiotechnology.com/content/8/1/21 Johanna Walter Svea Petersen Frank Stahl Thomas Scheper Stephan Barcikowski Journal of Nanobiotechnology 2010, 8:21 2010-08-23T00:00:00Z doi:10.1186/1477-3155-8-21 Journal of Nanobiotechnology 1477-3155 8 21 2010-08-23T00:00:00Z PDF Background: The search for naturally occurring nanocomposites with diverse properties for tissue engineering has been a major interest for biomaterial research. In this study, we investigated a nanofiber and nanoparticle based nanocomposite secreted from an insect-capturing plant, the Sundew, for cell attachment. The adhesive nanocomposite has demonstrated high biocompatibility and is ready to be used with minimal preparation. Results: Atomic force microscopy (AFM) conducted on the adhesive from three species of Sundew found that a network of nanofibers and nanoparticles with various sizes existed independent of the coated surface. AFM and light microscopy confirmed that the pattern of nanofibers corresponded to Alcian Blue staining for polysaccharide. Transmission electron microscopy identified a low abundance of nanoparticles in different pattern form AFM observations. In addition, energy-dispersive X-ray spectroscopy revealed the presence of Ca, Mg, and Cl, common components of biological salts. Study of the material properties of the adhesive yielded high viscoelasticity from the liquid adhesive, with reduced elasticity observed in the dried adhesive. The ability of PC12 neuron-like cells to attach and grow on the network of nanofibers created from the dried adhesive demonstrated the potential of this network to be used in tissue engineering, and other biomedical applications. Conclusions: This discovery demonstrates how a naturally occurring nanofiber and nanoparticle based nanocomposite from the adhesive of Sundew can be used for tissue engineering, and opens the possibility for further examination of natural plant adhesives for biomedical applications. http://www.jnanobiotechnology.com/content/8/1/20 Mingjun Zhang Scott Lenaghan Lijin Xia Lixin Dong Wei He William Henson Xudong Fan Journal of Nanobiotechnology 2010, 8:20 2010-08-18T00:00:00Z doi:10.1186/1477-3155-8-20 Journal of Nanobiotechnology 1477-3155 8 20 2010-08-18T00:00:00Z XML Background: Silver nanoparticles possess many unique properties that make them attractive for use in biological applications. Recently they received attention when it was shown that 10 nm silver nanoparticles were bactericidal, which is promising in light of the growing number of antibiotic resistant bacteria. An area that has been largely unexplored is the interaction of nanomaterials with viruses and the possible use of silver nanoparticles as an antiviral agent. Results: This research focuses on evaluating the interaction of silver nanoparticles with a New World arenavirus, Tacaribe virus, to determine if they influence viral replication. Surprisingly exposing the virus to silver nanoparticles prior to infection actually facilitated virus uptake into the host cells, but the silver-treated virus had a significant reduction in viral RNA production and progeny virus release, which indicates that silver nanoparticles are capable of inhibiting arenavirus infection in vitro. The inhibition of viral replication must occur during early replication since although pre-infection treatment with silver nanoparticles is very effective, the post-infection addition of silver nanoparticles is only effective if administered within the first 2-4 hours of virus replication. Conclusions: Silver nanoparticles are capable of inhibiting a prototype arenavirus at non-toxic concentrations and effectively inhibit arenavirus replication when administered prior to viral infection or early after initial virus exposure. This suggests that the mode of action of viral neutralization by silver nanoparticles occurs during the early phases of viral replication. http://www.jnanobiotechnology.com/content/8/1/19 Janice Speshock Richard Murdock Laura Braydich-Stolle Amanda Schrand Saber Hussain Journal of Nanobiotechnology 2010, 8:19 2010-08-18T00:00:00Z doi:10.1186/1477-3155-8-19 Journal of Nanobiotechnology 1477-3155 8 19 2010-08-18T00:00:00Z PDF Particle size is a key feature in determining performance of nanoparticles as drug carriers because it influences circulating half-life, cellular uptake and biodistribution. Because the size of particles has such a major impact on their performance, the uniformity of the particle population is also a significant factor. Particles comprised of the polymer poly(lactic-co-glycolic acid) (PLGA) are widely studied as therapeutic delivery vehicles because they are biodegradable and biocompatible. In fact, microparticles comprised of PLGA are already approved for drug delivery. Unfortunately, PLGA nanoparticles prepared by conventional methods usually lack uniformity. We developed a novel Fluidic NanoPrecipitation System (FNPS) to fabricate highly uniform PLGA particles. Several parameters can be fine-tuned to generate particles of various sizes. http://www.jnanobiotechnology.com/content/8/1/18 Hui Xie Jeffrey Smith Journal of Nanobiotechnology 2010, 8:18 2010-08-13T00:00:00Z doi:10.1186/1477-3155-8-18 Journal of Nanobiotechnology 1477-3155 8 18 2010-08-13T00:00:00Z XML Background: The redox dye, DCPIP, has recently shown to exhibit anti-melanoma activity in vitro and in vivo. On the other hand, there is increasing evidence that synthetic nanoparticles can serve as highly efficient carriers of drugs and vaccines for treatment of various diseases. These nanoparticles have shown to serve as potent tools that can increase the bioavailability of the drug/vaccine by facilitating absorption or conferring sustained and improved release. Here, we describe results on the effects of free- and nanoparticle-enclosed DCPIP as anti-angiogenesis and anti-inflammation agents in a human colon cancer HCT116 cell line in vitro, and in induced angiogenesis in ovo. Results: The studies described in this report indicate that (a) DCPIP inhibits proliferation of HCT116 cells in vitro; (b) DCPIP can selectively downregulate expression of the pro-angiogenesis growth factor, VEGF; (c) DCPIP inhibits activation of the transcriptional nuclear factor, NF-κB; (d) DCPIP can attenuate or completely inhibit VEGF-induced angiogenesis in the chick chorioallantoic membrane; (e) DCPIP at concentrations higher than 6 μg/ml induces apoptosis in HCT116 cells as confirmed by detection of caspase-3 and PARP degradation; and (f) DCPIP encapsulated in nanoparticles is equally or more effective than free DCPIP in exhibiting the aforementioned properties (a-e) in addition to reducing the expression of COX-2, and pro-inflammatory proteins IL-6 and IL-8. Conclusions: We propose that, DCPIP may serve as a potent tool to prevent or disrupt the processes of cell proliferation, tissue angiogenesis and inflammation by directly or indirectly targeting expression of specific cellular factors. We also propose that the activities of DCPIP may be long-lasting and/or enhanced if it is delivered enclosed in specific nanoparticles. http://www.jnanobiotechnology.com/content/8/1/17 Fadee Mondalek Sivapriya Ponnurangam Janita Govind Courtney Houchen Shrikant Anant Panayotis Pantazis Rama Ramanujam Journal of Nanobiotechnology 2010, 8:17 2010-07-15T00:00:00Z doi:10.1186/1477-3155-8-17 Journal of Nanobiotechnology 1477-3155 8 17 2010-07-15T00:00:00Z XML Background: Oxidative stress is imperative for its morbidity towards diabetic complications, where abnormal metabolic milieu as a result of hyperglycemia, leads to the onset of several complications. A biological antioxidant capable of inhibiting oxidative stress mediated diabetic progressions; during hyperglycemia is still the need of the era. The current study was performed to study the effect of biologically synthesized gold nanoparticles (AuNPs) to control the hyperglycemic conditions in streptozotocin induced diabetic mice. Results: The profound control of AuNPs over the anti oxidant enzymes such as GSH, SOD, Catalase and GPx in diabetic mice to normal, by inhibition of lipid peroxidation and ROS generation during hyperglycemia evidence their anti-oxidant effect during hyperglycemia. The AuNPs exhibited an insistent control over the blood glucose level, lipids and serum biochemical profiles in diabetic mice near to the control mice provokes their effective role in controlling and increasing the organ functions for better utilization of blood glucose. Histopathological and hematological studies revealed the non-toxic and protective effect of the gold nanoparticles over the vital organs when administered at dosage of 2.5 mg/kilogram.body.weight/day. ICP-MS analysis revealed the biodistribution of gold nanoparticles in the vital organs showing accumulation of AuNPs in the spleen comparatively greater than other organs. Conclusion: The results obtained disclose the effectual role of AuNPs as an anti-oxidative agent, by inhibiting the formation of ROS, scavenging free radicals; thus increasing the anti-oxidant defense enzymes and creating a sustained control over hyperglycemic conditions which consequently evoke the potential of AuNPs as an economic therapeutic remedy in diabetic treatments and its complications. http://www.jnanobiotechnology.com/content/8/1/16 Selvaraj BarathManiKanth Kalimuthu Kalishwaralal Muthuirulappan Sriram SureshBabu Ram Kumar Pandian Hyung-seop Youn SooHyun Eom Sangiliyandi Gurunathan Journal of Nanobiotechnology 2010, 8:16 2010-07-14T00:00:00Z doi:10.1186/1477-3155-8-16 Journal of Nanobiotechnology 1477-3155 8 16 2010-07-14T00:00:00Z XML Background: Previous in vitro studies have demonstrated that polyvinylpyrrolidone coated silver nanoparticles (PVP-coated AgNPs) have antiviral activity against HIV-1 at non-cytotoxic concentrations. These particles also demonstrate broad spectrum virucidal activity by preventing the interaction of HIV-1 gp120 and cellular CD4, thereby inhibiting fusion or entry of the virus into the host cell. In this study, we evaluated the antiviral activity of PVP-coated AgNPs as a potential topical vaginal microbicide to prevent transmission of HIV-1 infection using human cervical culture, an in vitro model that simulates in vivo conditions. Results: When formulated into a non-spermicidal gel (Replens) at a concentration of 0.15 mg/mL, PVP-coated AgNPs prevented the transmission of cell-associated HIV-1 and cell-free HIV-1 isolates. Importantly, PVP-coated AgNPs were not toxic to the explant, even when the cervical tissues were exposed continuously to 0.15 mg/mL of PVP-coated AgNPs for 48 h. Only 1 min of PVP-coated AgNPs pretreatment to the explant was required to prevent transmission of HIV-1. Pre-treatment of the cervical explant with 0.15 mg/mL PVP-coated AgNPs for 20 min followed by extensive washing prevented the transmission of HIV-1 in this model for 48 h. Conclusions: A formulation of PVP-coated AgNPs homogenized in Replens gel acts rapidly to inhibit HIV-1 transmission after 1 min and offers long-lasting protection of the cervical tissue from infection for 48 h, with no evidence of cytotoxicity observed in the explants.Based on this data, PVP-coated AgNPs are a promising microbicidal candidate for use in topical vaginal/cervical agents to prevent HIV-1 transmission, and further research is warranted. http://www.jnanobiotechnology.com/content/8/1/15 Humberto Lara Liliana Ixtepan-Turrent Elsa Garza-Trevino Cristina Rodriguez-Padilla Journal of Nanobiotechnology 2010, 8:15 2010-07-13T00:00:00Z doi:10.1186/1477-3155-8-15 Journal of Nanobiotechnology 1477-3155 8 15 2010-07-13T00:00:00Z XML Background: Recently we reported a nanocontainer based reduction triggered release system through an engineered transmembrane channel (FhuA Δ1-160; Onaca et al., 2008). Compound fluxes within the FhuA Δ1-160 channel protein are controlled sterically through labeled lysine residues (label: 3-(2-pyridyldithio)propionic-acid-N-hydroxysuccinimide-ester). Quantifying the sterical contribution of each labeled lysine would open up an opportunity for designing compound specific drug release systems. Results: In total, 12 FhuA Δ1-160 variants were generated to gain insights on sterically controlled compound fluxes: Subset A) six FhuA Δ1-160 variants in which one of the six lysines in the interior of FhuA Δ1-160 was substituted to alanine and Subset B) six FhuA Δ1-160 variants in which only one lysine inside the barrel was not changed to alanine. Translocation efficiencies were quantified with the colorimetric TMB (3,3',5,5'-tetramethylbenzidine) detection system employing horseradish peroxidase (HRP). Investigation of the six subset A variants identified position K556A as sterically important. The K556A substitution increases TMB diffusion from 15 to 97 [nM]/s and reaches nearly the TMB diffusion value of the unlabeled FhuA Δ1-160 (102 [nM]/s). The prominent role of position K556 is confirmed by the corresponding subset B variant which contains only the K556 lysine in the interior of the barrel. Pyridyl labeling of K556 reduces TMB translocation to 16 [nM]/s reaching nearly background levels in liposomes (13 [nM]/s). A first B-factor analysis based on MD simulations confirmed that position K556 is the least fluctuating lysine among the six in the channel interior of FhuA Δ1-160 and therefore well suited for controlling compound fluxes through steric hindrance. Conclusions: A FhuA Δ1-160 based reduction triggered release system has been shown to control the compound flux by the presence of only one inner channel sterical hindrance based on 3-(2-pyridyldithio)propionic-acid labeling (amino acid position K556). As a consequence, the release kinetic can be modulated by introducing an opportune number of hindrances. The FhuA Δ1-160 channel embedded in liposomes can be advanced to a universal and compound independent release system which allows a size selective compound release through rationally re-engineered channels. http://www.jnanobiotechnology.com/content/8/1/14 Arcan Guven Marco Fioroni Bernhard Hauer Ulrich Schwaneberg Journal of Nanobiotechnology 2010, 8:14 2010-06-25T00:00:00Z doi:10.1186/1477-3155-8-14 Journal of Nanobiotechnology 1477-3155 8 14 2010-06-25T00:00:00Z XML Background: The rapid growth of the nanotechnology industry and the wide application of various nanomaterials have raised concerns over their impact on the environment and human health. Yet little is known about the mechanism of cellular uptake and cytotoxicity of nanoparticles. An array of nanomaterials has recently been introduced into cancer research promising for remarkable improvements in diagnosis and treatment of the disease. Among them, quantum dots (QDs) distinguish themselves in offering many intrinsic photophysical properties that are desirable for targeted imaging and drug delivery. Results: We explored the kinetics and mechanism of cellular uptake of QDs with different surface coatings in two human mammary cells. Using fluorescence microscopy and laser scanning cytometry (LSC), we found that both MCF-7 and MCF-10A cells internalized large amount of QD655-COOH, but the percentage of endocytosing cells is slightly higher in MCF-7 cell line than in MCF-10A cell line. Live cell fluorescent imaging showed that QD cellular uptake increases with time over 40 h of incubation. Staining cells with dyes specific to various intracellular organelles indicated that QDs were localized in lysosomes. Transmission electron microscopy (TEM) images suggested a potential pathway for QD cellular uptake mechanism involving three major stages: endocytosis, sequestration in early endosomes, and translocation to later endosomes or lysosomes. No cytotoxicity was observed in cells incubated with 0.8 nM of QDs for a period of 72 h. Conclusions: The findings presented here provide information on the mechanism of QD endocytosis that could be exploited to reduce non-specific targeting, thereby improving specific targeting of QDs in cancer diagnosis and treatment applications. These findings are also important in understanding the cytotoxicity of nanomaterials and in emphasizing the importance of strict environmental control of nanoparticles. http://www.jnanobiotechnology.com/content/8/1/13 Yan Xiao Samuel Forry Xiugong Gao R Holbrook William Telford Alessandro Tona Journal of Nanobiotechnology 2010, 8:13 2010-06-15T00:00:00Z doi:10.1186/1477-3155-8-13 Journal of Nanobiotechnology 1477-3155 8 13 2010-06-15T00:00:00Z XML Background: Over the last decade safety concerns have arisen about the use of metal-based nanoparticles in the cosmetics field. Metal-based nanoparticles have been linked to both environmental and animal toxicity in a variety of studies. Perhaps the greatest concern involves the large amounts of TiO2 nanoparticles that are used in commercial sunscreens. As an alternative to using these potentially hazardous metal-based nanoparticles, we have isolated organic nanoparticles from English ivy (Hedera helix). In this study, ivy nanoparticles were evaluated for their potential use in sunscreens based on four criteria: 1) ability to absorb and scatter ultraviolet light, 2) toxicity to mammalian cells, 3) biodegradability, and 4) potential for diffusion through skin. Results: Purified ivy nanoparticles were first tested for their UV protective effects using a standard spectrophotometric assay. Next the cell toxicity of the ivy nanoparticles was compared to TiO2 nanoparticles using HeLa cells. The biodegradability of these nanoparticles was also determined through several digestion techniques. Finally, a mathematical model was developed to determine the potential for ivy nanoparticles to penetrate through human skin. The results indicated that the ivy nanoparticles were more efficient in blocking UV light, less toxic to mammalian cells, easily biodegradable, and had a limited potential to penetrate through human skin. When compared to TiO2 nanoparticles, the ivy nanoparticles showed decreased cell toxicity, and were easily degradable, indicating that they provided a safer alternative to these nanoparticles. Conclusions: With the data collected from this study, we have demonstrated the great potential of ivy nanoparticles as a sunscreen protective agent, and their increased safety over commonly used metal oxide nanoparticles. http://www.jnanobiotechnology.com/content/8/1/12 Lijin Xia Scott Lenaghan Mingjun Zhang Zhili Zhang Quanshui Li Journal of Nanobiotechnology 2010, 8:12 2010-06-09T00:00:00Z doi:10.1186/1477-3155-8-12 Journal of Nanobiotechnology 1477-3155 8 12 2010-06-09T00:00:00Z XML