http://www.jnanobiotechnology.com The latest research articles published by Journal of Nanobiotechnology 2013-05-29T00:00:00Z Background: Gastric cancer is 2th most common cancer in China, and is still the second most common cause of cancer-related death in the world. Successful development of safe and effective nanoprobes for in vivo gastric cancer targeting imaging is a big challenge. This study is aimed to develop folic acid (FA)-conjugated silica coated gold nanoclusters (AuNCs) for targeted dual-modal fluorescent and X-ray computed tomography imaging (CT) of in vivo gastric cancer cells.MethodAuNCs were prepared, silica was coated on the surface of AuNCs, then folic acid was covalently anchored on the surface of AuNCs, resultant FA-conjugated AuNCs@SiO2 nanoprobes were investigated their cytotoxicity by MTT method, and their targeted ability to FR(+) MGC803 cells and FR(−) GES-1 cells. Nude mice model loaded with MGC803 cells were prepared, prepared nanoprobes were injected into nude mice via tail vein, and then were imaged by fluorescent and X-ray computed tomography (CT) imaging. Results: FA-conjugated AuNCs@SiO2 nanoprobes exhibited good biocompatibility, and could target actively the FR(+) MGC-803 cells and in vivo gastric cancer tissues with 5 mm in diameter in nude mice models, exhibited excellent red emitting fluorescence imaging and CT imaging. Conclusion: The high-performance FA-conjugated AuNCs@SiO2 nanoprobes can target in vivo gastric cancer cells, can be used for fluorescent and CT dual-mode imaging, and may own great potential in applications such as targeted dual-mode imaging of in vivo early gastric cancer and other tumors with FR positive expression in near future. http://www.jnanobiotechnology.com/content/11/1/17 Zhijun Zhou Chunlei Zhang Qirong Qian Jiebing Ma Peng Huang Xi zhang Liyuan Pan Guo Gao Hualin Fu Shen Fu Hua Song Xiao Zhi Jian Ni Daxiang Cui Journal of Nanobiotechnology 2013, null:17 2013-05-29T00:00:00Z doi:10.1186/1477-3155-11-17 /content/figures/1477-3155-11-17-toc.gif Journal of Nanobiotechnology 1477-3155 ${item.volume} 17 2013-05-29T00:00:00Z XML Background: Nanocapsules have many applications in the drug, cosmetic, fragrance, and food industries. In this study, Crataegus azarolus L. nanocapsules were prepared by a modified emulsion diffusion technique. Methods: In this technique a shell was first made from the polyester triblock copolymer poly(ethylene glycol)-poly(butylene adipate)-poly(ethylene glycol) (PEG-PBA-PEG) and then olive oil was set as the core of the nanocapsule by a method known as the polymer deposition solvent evaporation method. Varying amounts of C. azarolus extract, polymer, and olive oil were mixed in acetone and then added to water on a shaker. Finally, the acetone was removed by vacuuming. Results: The size of the prepared nanocapsules were measured with a particle size analysis report (PSAR) and identified by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR). Conclusions: Our experiments showed that the size of the nanocapsules depends on the preparation conditions, i.e., the ratio of polymer to oil and concentrations of polymer and plant extract. A ratio of 1:0.25 polymer to oil was shown to be more suitable for the formation of smaller nanocapsules of C. azarolus. http://www.jnanobiotechnology.com/content/11/1/16 Akbar Esmaeili Soraya Rahnamoun Fariba Sharifnia Journal of Nanobiotechnology 2013, null:16 2013-05-29T00:00:00Z doi:10.1186/1477-3155-11-16 /content/figures/1477-3155-11-16-toc.gif Journal of Nanobiotechnology 1477-3155 ${item.volume} 16 2013-05-29T00:00:00Z XML Background: Dengue is today the most significant of arboviral diseases. Novel tools are necessary to effectively address the problem of dengue. Virus-like particles (VLP) offer a versatile nanoscale platform for developing tools with potential biomedical applications. From the perspective of a potentially useful dengue-specific tool, the dengue virus envelope protein domain III (EDIII), endowed with serotype-specificity, host receptor recognition and the capacity to elicit virus-neutralizing antibodies, is an attractive candidate. Methods: We have developed a strategy to co-express and co-purify Hepatitis B virus surface (S) antigen in two forms: independently and as a fusion with EDIII. We characterized these physically and functionally. Results: The two forms of the S antigen associate into VLPs. The ability of these to display EDIII in a functionally accessible manner is dependent upon the relative levels of the two forms of the S antigen. Mosaic VLPs containing the fused and un-fused components in 1:4 ratio displayed maximal functional competence. Conclusions: VLPs armed with EDIII may be potentially useful in diagnostic, therapeutic and prophylactic applications. http://www.jnanobiotechnology.com/content/11/1/15 Niyati Khetarpal Ankur Poddar Satish Nemani Nisha Dhar Aravind Patil Priyanka Negi Ashiya Perween Ramaswamy Viswanathan Heinrich Lünsdorf Poornima Tyagi Rajendra Raut Upasana Arora Swatantra Jain Ursula Rinas Sathyamangalam Swaminathan Navin Khanna Journal of Nanobiotechnology 2013, null:15 2013-05-25T00:00:00Z doi:10.1186/1477-3155-11-15 /content/figures/1477-3155-11-15-toc.gif Journal of Nanobiotechnology 1477-3155 ${item.volume} 15 2013-05-25T00:00:00Z XML Background: Introduction of effective point-of-care devices for use in medical diagnostics is part of strategies to combat accelerating health-care costs. Molecular motor driven nanodevices have unique potentials in this regard due to unprecedented level of miniaturization and independence of external pumps. However motor function has been found to be inhibited by body fluids. Results: We report here that a unique procedure, combining separation steps that rely on antibody-antigen interactions, magnetic forces applied to magnetic nanoparticles (MPs) and the specificity of the actomyosin bond, can circumvent the deleterious effects of body fluids (e.g. blood serum). The procedure encompasses the following steps: (i) capture of analyte molecules from serum by MP-antibody conjugates, (ii) pelleting of MP-antibody-analyte complexes, using a magnetic field, followed by exchange of serum for optimized biological buffer, (iii) mixing of MP-antibody-analyte complexes with actin filaments conjugated with same polyclonal antibodies as the magnetic nanoparticles. This causes complex formation: MP-antibody-analyte-antibody-actin, and magnetic separation is used to enrich the complexes. Finally (iv) the complexes are introduced into a nanodevice for specific binding via actin filaments to surface adsorbed molecular motors (heavy meromyosin). The number of actin filaments bound to the motors in the latter step was significantly increased above the control value if protein analyte (50–60 nM) was present in serum (in step i) suggesting appreciable formation and enrichment of the MP-antibody-analyte-antibody-actin complexes. Furthermore, addition of ATP demonstrated maintained heavy meromyosin driven propulsion of actin filaments showing that the serum induced inhibition was alleviated. Detailed analysis of the procedure i-iv, using fluorescence microscopy and spectroscopy identified main targets for future optimization. Conclusion: The results demonstrate a promising approach for capturing analytes from serum for subsequent motor driven separation/detection. Indeed, the observed increase in actin filament number, in itself, signals the presence of analyte at clinically relevant nM concentration without the need for further motor driven concentration. Our analysis suggests that exchange of polyclonal for monoclonal antibodies would be a critical improvement, opening for a first clinically useful molecular motor driven lab-on-a-chip device. http://www.jnanobiotechnology.com/content/11/1/14 Saroj Kumar Lasse ten Siethoff Malin Persson Nuria Albet-Torres Alf Månsson Journal of Nanobiotechnology 2013, null:14 2013-05-03T00:00:00Z doi:10.1186/1477-3155-11-14 /content/figures/1477-3155-11-14-toc.gif Journal of Nanobiotechnology 1477-3155 ${item.volume} 14 2013-05-03T00:00:00Z XML Background: The conjugation of gold nanoparticles with biocides such as natural products, oligosaccharides, DNA, proteins has attracted great attention of scientists recently. Gold NPs covered with biologically important molecules showed significant enhancement in biological activity in comparison with the activity of the free biocides. However, these reports are not very systematic and do not allow to draw definitive conclusions. We therefore embarked in a systematic study related to the synthesis and characterization of biocidal activities of Au nanoparticles conjugated to a wide variety of synthetic and natural biomolecules. In this specific report, we investigated the activity of a synthetic biocide, 2-4, Dihydroxybenzene carbodithioic acid (DHT). Results: Au nanoparticles (NP) with a mean size of about 20 nm were synthesized and functionalized in one pot with the help of biocide 2,4-Dihydroxybenzene carbodithioic acid (DHT) to reduce HAuCl4 in aqueous solution. Conjugation of DHT with gold was confirmed by FT-IR and the amount of DHT conjugated to the Au nanoparticles was found to be 7% by weight by measuring the concentration of DHT in the supernatant after centrifugation of the Au NPs. To ascertain the potential for in vivo applications, the stability of the suspensions was investigated as a function of pH, temperature and salt concentration. Antibacterial, antifungal, insecticidal and cytotoxic activities of the Au-DHT conjugates were compared with those of pure DHT and of commercially available biocides. In all cases, the biocidal activity of the Au-DHT conjugates was comparable to that of commercial products and of DHT. Conclusions: Since the DHT concentration in the Au-DHT conjugates was only about 7%, our results indicate that conjugation to the Au NPs boosts the biocidal activity of DHT by about 14 times. The suspensions were found to be stable for several days at temperatures of up to 100°C, salt concentrations up to 4 mol/L and a pH range of 2-13. http://www.jnanobiotechnology.com/content/11/1/13 Syeda Naz Nazar Islam Muhammad Shah Syed Alam Zafar Iqbal Massimo Bertino Louis Franzel Afifa Ahmed Journal of Nanobiotechnology 2013, null:13 2013-04-22T00:00:00Z doi:10.1186/1477-3155-11-13 /content/figures/1477-3155-11-13-toc.gif Journal of Nanobiotechnology 1477-3155 ${item.volume} 13 2013-04-22T00:00:00Z XML Background: Controlled restriction of cellular movement using microfluidics allows one to study individual cells to gain insight into aspects of their physiology and behaviour. For example, the use of micron-sized growth channels that confine individual Escherichia coli has yielded novel insights into cell growth and death. To extend this approach to other species of bacteria, many of whom have dimensions in the sub-micron range, or to a larger range of growth conditions, a readily-fabricated device containing sub-micron features is required. Results: Here we detail the fabrication of a versatile device with growth channels whose widths range from 0.3 μm to 0.8 μm. The device is fabricated using electron beam lithography, which provides excellent control over the shape and size of different growth channels and facilitates the rapid-prototyping of new designs. Features are successfully transferred first into silicon, and subsequently into the polydimethylsiloxane that forms the basis of the working microfluidic device. We demonstrate that the growth of sub-micron scale bacteria such as Lactococcus lactis or Escherichia coli cultured in minimal medium can be followed in such a device over several generations. Conclusions: We have presented a detailed protocol based on electron beam fabrication together with specific dry etching procedures for the fabrication of a microfluidic device suited to study submicron-sized bacteria. We have demonstrated that both Gram-positive and Gram-negative bacteria can be successfully loaded and imaged over a number of generations in this device. Similar devices could potentially be used to study other submicron-sized organisms under conditions in which the height and shape of the growth channels are crucial to the experimental design. http://www.jnanobiotechnology.com/content/11/1/12 Martinus Moolman Zhuangxiong Huang Sriram Krishnan Jacob Kerssemakers Nynke Dekker Journal of Nanobiotechnology 2013, null:12 2013-04-10T00:00:00Z doi:10.1186/1477-3155-11-12 /content/figures/1477-3155-11-12-toc.gif Journal of Nanobiotechnology 1477-3155 ${item.volume} 12 2013-04-10T00:00:00Z XML The interface between engineering and molecular life sciences has been fertile ground for advancing our understanding of complex biological systems. Engineered microstructures offer a diverse toolbox for cellular and molecular biologists to direct the placement of cells and small organisms, and to recreate biological functions in vitro: cells can be positioned and connected in a designed fashion, and connectivity and community effects of cells studied. Because of the highly polar morphology and finely compartmentalized functions of neurons, microfabricated cell culture systems and related on-chip technologies have become an important enabling platform for studying development, function and degeneration of the nervous system at the molecular and cellular level. Here we review some of the compartmentalization techniques developed so far to highlight how high-precision control of neuronal connectivity allows new approaches for studying axonal and synaptic biology. http://www.jnanobiotechnology.com/content/11/1/11 Cecilia Brunello Ville Jokinen Prasanna Sakha Hideyuki Terazono Fumimasa Nomura Tomoyuki Kaneko Sari Lauri Sami Franssila Claudio Rivera Kenji Yasuda Henri Huttunen Journal of Nanobiotechnology 2013, null:11 2013-04-10T00:00:00Z doi:10.1186/1477-3155-11-11 /content/figures/1477-3155-11-11-toc.gif Journal of Nanobiotechnology 1477-3155 ${item.volume} 11 2013-04-10T00:00:00Z XML Background: The ever-present threat of infectious disease, e.g. influenza pandemics, and the increasing need for new and effective treatments in immunotherapy are the driving forces that motivate research into new and innovative vaccine platforms. Ideally, such platforms should trigger an efficient CTL response, be safe, and easy to manufacture. We recently developed a novel nanoparticle adjuvant comprised of papaya mosaic virus (PapMV) coat protein (CP) assembled around an RNA. The PapMV nanoparticle is an efficient vaccine platform in which the peptide antigen is fused to the C-terminus of the PapMV CP, leading to nanoparticles presenting surface-exposed epitope. The fusion stabilizes the epitope and improves its immunogenicity. We found recently that C-terminal fusions are not always efficient, depending on the nature of the peptide fused to the platform. Results: We chose a CTL epitope derived from the nucleocapsid (NP) of influenza virus (NP147-155) for this proof-of-concept demonstration. Recombinant nanoparticles harbouring a fusion at the N-terminus were more efficient in triggering a CTL response. Efficacy appeared to be linked to the stability of the nanoparticles at 37°C. We also showed that discs—smaller than nanoparticles—made of 20 subunits of PapMV CP are less efficient for induction of a CTL response in mice, revealing that assembly of the recombinant PapMV CP into nanoparticles is crucial to triggering an efficient CTL response. Conclusion: The point of fusion on the PapMV vaccine platform is critical to triggering an efficient CTL response. Efficacy is linked to nanoparticle stability; nanoparticles must be stable at 37°C but remain susceptible to cellular proteases to ensure efficient processing of the CTL epitope by cells of the immune system. The results of this study improve our understanding of the PapMV vaccine platform, which will facilitate the design of efficient vaccines to various infectious threats. http://www.jnanobiotechnology.com/content/11/1/10 Cindy Babin Nathalie Majeau Denis Leclerc Journal of Nanobiotechnology 2013, null:10 2013-04-04T00:00:00Z doi:10.1186/1477-3155-11-10 /content/figures/1477-3155-11-10-toc.gif Journal of Nanobiotechnology 1477-3155 ${item.volume} 10 2013-04-04T00:00:00Z XML Background: The potential nanocarrier polyamidoamine (PAMAM) generation 5 (G5-NH2) dendrimer has been shown to evoke lasting neuronal depolarization and cell death in a concentration-dependent manner. In this study we explored the early progression of G5-NH2 action in brain tissue on neuronal and astroglial cells. Results: In order to describe early mechanisms of G5-NH2 dendrimer action in brain tissue we assessed G5-NH2 trafficking, free intracellular Ca2+ and mitochondrial membrane potential (ΨMITO) changes in the rat hippocampal slice by microfluorimetry. With the help of fluorescent dye conjugated G5-NH2, we observed predominant appearance of the dendrimer in the plasma membrane of pyramidal neurons and glial cells within 30 min. Under this condition, G5-NH2 evoked robust intracellular Ca2+ enhancements and ΨMITO depolarization both in pyramidal neurons and astroglial cells. Intracellular Ca2+ enhancements clearly preceded ΨMITO depolarization in astroglial cells. Comparing activation dynamics, neurons and glia showed prevalence of lasting and transient ΨMITO depolarization, respectively. Transient as opposed to lasting ΨMITO changes to short-term G5-NH2 application suggested better survival of astroglia, as observed in the CA3 stratum radiatum area. We also showed that direct effect of G5-NH2 on astroglial ΨMITO was significantly enhanced by neuron-astroglia interaction, subsequent to G5-NH2 evoked neuronal activation. Conclusion: These findings indicate that the interaction of the PAMAM dendrimer with the plasma membrane leads to robust activation of neurons and astroglial cells, leading to mitochondrial depolarization. Distinguishable dynamics of mitochondrial depolarization in neurons and astroglia suggest that the enhanced mitochondrial depolarization followed by impaired oxidative metabolism of neurons may be the primary basis of neurotoxicity. http://www.jnanobiotechnology.com/content/11/1/9 Gabriella Nyitrai László Héja István Jablonkai Ildikó Pál Júlia Visy Julianna Kardos Journal of Nanobiotechnology 2013, null:9 2013-04-04T00:00:00Z doi:10.1186/1477-3155-11-9 /content/figures/1477-3155-11-9-toc.gif Journal of Nanobiotechnology 1477-3155 ${item.volume} 9 2013-04-04T00:00:00Z XML Background: Zero-mode waveguides (ZMWs) are photonic nanostructures that create highly confined optical observation volumes, thereby allowing single-molecule-resolved biophysical studies at relatively high concentrations of fluorescent molecules. This principle has been successfully applied in single-molecule, real-time (SMRT®) DNA sequencing for the detection of DNA sequences and DNA base modifications. In contrast, RNA sequencing methods cannot provide sequence and RNA base modifications concurrently as they rely on complementary DNA (cDNA) synthesis by reverse transcription followed by sequencing of cDNA. Thus, information on RNA modifications is lost during the process of cDNA synthesis. Results: Here we describe an application of SMRT technology to follow the activity of reverse transcriptase enzymes synthesizing cDNA on thousands of single RNA templates simultaneously in real time with single nucleotide turnover resolution using arrays of ZMWs. This method thereby obtains information from the RNA template directly. The analysis of the kinetics of the reverse transcriptase can be used to identify RNA base modifications, shown by example for N6-methyladenine (m6A) in oligonucleotides and in a specific mRNA extracted from total cellular mRNA. Furthermore, the real-time reverse transcriptase dynamics informs about RNA secondary structure and its rearrangements, as demonstrated on a ribosomal RNA and an mRNA template. Conclusions: Our results highlight the feasibility of studying RNA modifications and RNA structural rearrangements in ZMWs in real time. In addition, they suggest that technology can be developed for direct RNA sequencing provided that the reverse transcriptase is optimized to resolve homonucleotide stretches in RNA. http://www.jnanobiotechnology.com/content/11/1/8 Igor Vilfan Yu-Chih Tsai Tyson Clark Jeffrey Wegener Qing Dai Chengqi Yi Tao Pan Stephen Turner Jonas Korlach Journal of Nanobiotechnology 2013, null:8 2013-04-03T00:00:00Z doi:10.1186/1477-3155-11-8 /content/figures/1477-3155-11-8-toc.gif Journal of Nanobiotechnology 1477-3155 ${item.volume} 8 2013-04-03T00:00:00Z XML