Nanomedicine Journal
Volume:2 Issue: 2, Spring 2015

A sensitive monitoring of biological analytes, such as biomolecules (protein, lipid, DNA and RNA), and biological cells (blood cell, virus and bacteria), is essential to assess and avoid risks for human health. Nanobiosensors, analytical devices that combine a biologically sensitive element with a nanostructured transducer, are being widely used for molecular detection of biomarkers associated with diagnosis of disease and detection of infectious organisms. Nanobiosensors show certain advantages over laboratory and many field methods due to their inherent specificity, simplicity and quick response. In this review, recent progress in the development of nanobiosensors in medicine is illuminated. In addition, this article reviews different kinds of bio-receptors and transducers employed in nanobiosensors. In the last section, overview of the development and application of various nanomaterials and nanostructures in biosensing has been provided. Considering all of these aspects, it can be stated that nanobiosensors offer the possibility of diagnostic tools with increased sensitivity, specificity, and reliability for medical applications.

Our present study sought to evaluate hepatoprotective and antioxidant effects of methanol extract of Azolla microphylla phytochemically synthesized gold nanoparticles (GNaP) in acetaminophen (APAP) - induced hepatotoxicity of fresh water common carp fish. GNaP were prepared by green synthesis method using methanol extract of Azolla microphylla. Twenty four fishes weighing 146 ± 2.5 g were used in this experiment and these were divided into four experimental groups, each comprising 6 fishes. Group 1 served as control. Group 2 fishes were exposed to APAP (500 mg/kg) for 24 h. Groups 3 and 4 fishes were exposed to APAP (500 mg/kg) + GNaP (2.5 mg/kg) and GNaP (2.5 mg/kg) for 24 h, respectively. The hepatoprotective and antioxidant potentials were assessed by measuring liver damage, biochemical parameters, ions status, and histological alterations. APAP exposed fish showed significant elevated levels of metabolic enzymes (LDH, G6PDH and MDH), hepatotoxic markers (GPT, GOT and ALP), reduced hepatic glycogen, lipids, protein, albumin, globulin, increased levels of bilirubin, creatinine, and oxidative stress markers (TBRAS, LHP and protein carbonyl), altered the tissue enzymes (SOD, CAT, GSH-Px and GST) non-enzyme (GSH), cellular sulfhydryl (T-SH, P-SH and NP-SH) levels, reduced hepatic ions (Ca2+, Na+ and K+), and abnormal liver histology. It was observe that GNaP has reversal effects on the levels of above mentioned parameters in APAP hepatotoxicity. Azolla microphylla phytochemically synthesized GNaP protects liver against oxidative damage and tissue damaging enzyme activities and could be used as an effective protector against acetaminophen-induced hepatic damage in fresh water common carp fish.

Although viral vectors are considered efficient gene transfer agents, their board application has been limited by toxicity, immunogenicity, mutagenicity and small gene carrying capacity. Non-viral vectors are safe but they suffer from low transfection efficiency. In the present study, polyallylamine (PAA) in two molecular weights (15 and 65 kDa) was modified by alkane derivatives in order to increase transfection activity and to decrease cytotoxicity. Modified PAA was synthesized using three alkane derivatives (1-bromobutane, 1-bromohexane and 1-bromodecane) in different grafting percentages (10, 30 and 50). The condensation ability of modified PAA was determined by ethidium bromide test. The prepared polyplexes, complexes of modified PAA and DNA, were characterized by size and zeta potential. Transfection activity of polyplexes was checked in Neuro2A cells. The cytotoxicity of vector was examined in the same cell line. DNA condensation ability of PAA was decreased after modification but modified polymer could still condense DNA at moderate and high carrier to plasmid (C/P) ratios. Most of polyplexes composed of modified polymer had mean size less than 350 nm. They showed a positive zeta potential, but some vectors with high percentage of grafting had negative surface charge. Transfection efficiency was increased by modification of PAA by 1-bromodecane in grafting percentages of 30 and 50%. Modification of polymer reduced polymer cytotoxicity especially in C/P ratio of 2. Results of the present study indicated that modification of PAA with alkane derivatives can help to prepare gene carriers with better transfection activity and less cytotoxicity.

Bacterial biofilm formation causes many persistent and chronic infections. The matrix protects biofilm bacteria from exposure to innate immune defenses and antibiotic treatments. The purpose of this study was to evaluate the biofilm formation of clinical isolates of Pseudomonas aeruginosa and the activity of zinc oxide nanoparticles (ZnO NPs) on biofilm. After collecting bacteria from clinical samples of hospitalized patients, the ability of organisms were evaluated to create biofilm by tissue culture plate (TCP) assay. ZnO NPs were synthesized by sol gel method and the efficacy of different concentrations (50- 350 µg/ml) of ZnO NPs was assessed on biofilm formation and also elimination of pre-formed biofilm by using TCP method. The average diameter of synthesized ZnO NPs was 20 nm. The minimum inhibitory concentration of nanoparticles was 150- 158 μg/ml and the minimum bactericidal concentration was higher (325 µg/ml). All 15 clinical isolates of P. aeruginosa were able to produce biofilm. Treating the organisms with nanoparticles at concentrations of 350 μg/ml resulted in more than 94% inhibition in OD reduction%. Molecular analysis showed that the presence of mRNA of pslA gene after treating bacteria with ZnO NPs for 30 minutes. The results showed that ZnO NPs can inhibit the establishment of P. aeruginosa biofilms and have less effective in removing pre-formed biofilm. However the tested nanoparticles exhibited anti-biofilm effect, but mRNA of pslA gene could be still detected in the medium by RT-PCR technique after 30 minutes treatment with ZnO.

Carbon nanotube (CNT) has been widely applied at molecular and cellular levels due to its exceptional properties. Studies based on conjugation of CNTs with biological molecules indicated that biological activity is preserved. Polyethylenimine (PEI) is explored in designing novel gene delivery vectors due to its ability to condense plasmid DNA through electrostatic attraction. In this study functionalization and grafting polyethylenimine onto the surface of carbon nanotube was used to improve the solubility and biocompatibility. The effect of molecular weight of polymer on final efficacy of vectors has been investigated using three different molecular weights of polymer. In this study no linker was used and both segments (PEI and CNT) were directly attached resulted in the synthesis of three different vectors. Synthesized vectors were tested for their ability to condense plasmid DNA and cellular toxicity using ethidium bromide and MTT assays. Size and Zeta potential of nanoparticles was determined using Malvern zeta sizer. Evaluation of transfection efficiency of vectors was carried out on N2A cell line by different methods including qualitative fluorescence imaging, flow cytometry and luciferase assay. All three synthesized vectors bear positive surface charges with sizes in the range of 85-190 nm. More than 80 percent of treated cells were viable and in the case of V25 significant improvement in reducing cytotoxicity compared to unmodified polymer was observed. Obtained results indicated that vector containing PEI 1.8 kDa has the greatest improvement in terms of its transfection efficiency compared to unmodified polymer. Conjugation of PEI with carbon nanotube les to new vectors with lowered cytotoxicity and higher transfection efficiency. The highest transfection efficiency was obtained with the lowest molecular weight PEI.

Objecttive(s): Despite the poor mechanical properties of hydroxyapatite, its unique biological properties leads we think about study on improving its properties rather than completely replacing it with other biomaterials. Accordingly, in this study we introduced hydroxyapatite reinforced with hardystonite as a novel bio-nanocompositeand evaluate its in-vitro bioactivity with the aim of developing a mechanically strong and highly porous scaffold for bone tissue engineering applications. Natural Hydroxyapatite (NHA)-Hardystonite (HT) nanocomposite with different percentage of HT was synthesized by mechanical activation method and subsequent heating annealing process. This study showed that the addition of HT to HA not only increases the mechanical properties of HA but also improves its bioactivity. Dissolution curves presented in this study indicated that the pH value of SBF solution in the vicinity of HA-HT nanocomposite increases during the first week of experiment and decreases to blood pH at the second weekend. Hardystonite was composed of nano-crystalline structure with approximately diameter 40 nm. Specimens were composed of a blend of pure calcite (CaCO3) (98% purity, Merck), silica amorphous (SiO2) (98% purity, Merck) powder and pure zinc oxide (ZnO) with 50 % wt., 30 %wt and 20 %wt., respectively. These powders were milled by high energy ball mill using ball-to- powder ratio 10:1 and rotation speed of 600 rpm for 5 and 10 h. Then, the mixture mechanical activated has been pressed under 20 MPa. The samples pressed have been heated at 1100 ºC for 3 h in muffle furnace at air atmosphere. X-ray diffraction (XRD), scanning electron microscopy (SEM) and BET performed on the samples to characterize. According to XRD results, the sample milled for 10 h just indicated the hardystonite phase, while the sample milled for 5 h illustrate hardystonite phase along with several phases. In fact, our study indicated that hardystonite powder was composed of nano-crystalline structure, about 40 nm, can be prepared by mechanical activation to use as a new biomaterials for orthopedic applications.

In recent years, the biosynthesis of gold nanoparticles has been the focus of interest because of their emerging application in a number of areas such as biomedicine. In the present study we report the extracellular biosynthesis of gold nanoparticles (AuNPs) by using a positive bacterium named Streptomyces fulvissimus isolate U from rice fields of Guilan Province, Iran. From over 20 Streptomyces isolates collected, isolate U showed high AuNPs biosynthesis activity. To determine its taxonomical identity, its morphology was characterized by scanning electron microscope and partial molecular analysis performed by PCR. In this regard, 16S rDNA of isolate U was amplified using universal bacterial primers FD1 and RP2. The PCR products were purified and sequenced. Sequence analysis of 16S rDNA was then conducted using NCBI BLAST method. In biosynthesis of AuNPs by this bacterium, the biomass of bacterium exposed to the HAuCl4 solution. The nanoparticles obtained were characterized by UV-Visible spectroscopy, transmission electron microscopy (TEM) and Energy dispersive X-ray (EDX) spectroscopy and X-ray diffraction spectroscopy (XRD) analyses. Our results indicated that Streptomyces fulvissimus isolateU bio-synthesizes extracellular AuNPs in the range of 20-50 nm. This technique of green synthesis of AuNPs by a microbial source may become a promising method because of its environmental safety. Its optimization may make it a potential procedure for industrial production of gold nanoparticles.

This paper describes synthesisPolyvinyl Alcohol/CaF2:Er nanofibers because of its photoluminescence properties. First, CaF2:Er nanocomposite synthesized with co-precipitation method. In order to prepare polyvinyl alcohol (PVA)/CaF2:Er nanofibers, CaF2:Er nanocomposites were added to the polyvinyl alcohol (PVA) polymer. PVA/CaF2:Er composite nanofibers were successfully prepared by electrospinning technique. X-Ray Diffraction (XRD) pattern and Transmission Electron Microscopy (TEM) images indicate that the CaF2:Er nanocomposite was formed with cubic phase and the average crystalline size was calculated using the Scherrer''s equation is about 26-28 nm. Scanning Electron Microscopy (SEM) images show that the diameters of the fine nanofibers are in the range of 60-110 nm. For studying luminescence properties of the nanofibers, the samples excited with different wavelengths and show excellent Up-Conversion luminescence transition. Photoluminescence spectrums of the PVA/CaF2:Er nanofibers illustrate up-conversion luminescence process. This unique property can have high potential for laser application and bio-imaging in medical technology.