In the light of promising potency of selenium nanoparticles in biomedical applications, this is the first study to report the synergistic antibacterial activity of these nanoparticles and lysozyme. ...The nanohybrid system was prepared with various concentrations of each component. Resistance of Escherichia coli and Staphylococcus aureus was compared in the presence of individual Nano and Bio counterparts as well as the nanohybrid system. Upon interaction of SeNPs with Lysozyme, the nanohybrid system efficiently enhanced the antibacterial activity compared to the protein. Therefore, SeNPs play an important role in inhibition of bacterial growth at very low concentrations of protein; whereas very high amount of the protein is required to inhibit bacterial growth individually. On the other hand, lysozyme has also played a vital role in antibacterial property of SeNPs, inducing 100% inhibition at very low concentration of each component. Hence, presence of both nano and bio counterparts induced vital interplay in the Nanohybrid system. The aged samples also presented good stability of SeNPs both as the intact and complex form. Results of this effort highlight design of nanohybrid systems with synergistic antibacterial properties to overcome the emerging antibiotic resistance as well as to define fruitful applications in biomedicine and food safety.
The current study aimed to formulate Selenium-Chitosan-Mupirocin (M-SeNPs-CCH) complex. The nanohybrid system was prepared using chitosan-cetyltrimethylammonium bromide (CTAB)-based hydrogel (CCH) ...that entrapped mupirocin (M) and selenium nanoparticles (SeNPs). The in vitro studies were performed by evaluation of the antibacterial activity and toxicity on L929 mouse fibroblast cell line. The in vivo study was conducted on rat diabetic wound infection model that was infected by mupirocin-methicillin-resistant Staphylococcus aureus (MMRSA). The wounds were treated by M-SeNPs-CCH nanohybrid system with concentrations of M; 20 mg/ml, CCH; 2 mg/ml and SeNPs; 512 μg/ml in two times/day for 21 days. The therapeutic effect of this nanohybrid system was evaluated by monitoring wound contraction and histopathological changes. Evaluation of the average wound healing time showed a significant difference between the treatment and control groups (P≤0.05). The histopathological study indicated that the amount of wound healing was considerable in M-SeNPs-CCH nanohybrid system groups compared to the control and M groups. The M-SeNPs-CCH nanohybrid system formulated in this study was able to reduce 3-fold MIC of mupirocin with synergistic antibacterial activity as well as to play a significant role in wound contraction, angiogenesis, fibroblastosis, collagenesis, proliferation of hair follicle, and epidermis growth compared to the control group (P ≤ 0.05). This research suggests that this nanohybrid system might be a development for the treatment of diabetic wound infection at mild stage.
Today, Gold Nanorods have promised variety of applications in conjugation with biomolecules of interest. Discovery of functional amyloids has also been highlighted with possible use in designing high ...performance materials. To exploit dual properties of both Nano and Bio counterparts in new functional materials, this effort has focused on synthesis of a potential hybrid system of Gold nanorods (GNRs) and HSA amyloid fibrils to develop a conductive nanoscaffold. UV-Vis spectroscopy, Thioflavin T (ThT) assay, Far-UV Circular Dichroism (CD) spectropolarimetry, fluorescence and Transmission Electron microscopy were used to characterize formation of the nanostructures and amyloid fibrils. Surface plasmon resonance of GNRs was also monitored upon interaction with HSA amyloid fibrils, showing that the plasmonic component of the hybrid system has maintained its characteristic rod morphology without any perturbations. Analysis of Nyquist plots for the hybrid nanoscaffold showed that the electronic behavior of the hybrid system has been enhanced due to the presence of the assembled GNRs. Results of this investigation highlight the possibility of fabricating hybrid nano-bioscaffolds as promising candidates in versatile biomedical and biosensing applications.
Gold nanorods (GNRs) have been nominated as a promising candidate for a variety of biological applications; however, the cationic surfactant layer that surrounds a nanostructure places limits on its ...biological applicability. Herein, CTAB-GNRs were functionalized via a ligand exchange method using a (C(HK)4-mini PEG-RGD)-peptide to target the overexpressed αvβ3 integrin in cancerous cells, increase the biocompatibility, and gain the ability of gene/drug delivery, simultaneously. To confirm an acceptable functionalization, UV–Visible, FTIR, and Raman spectroscopy, zeta potential, and transmission electron microscopy of nanostructures were done. MTT assay was applied to study the cytotoxicity of nanostructures on two cell lines, HeLa and MDA-MB-231, as positive and negative αvβ3 integrin receptors, respectively. The cytotoxic effect of peptide-functionalized GNRs (peptide-f-GNRs) was less than that of CTAB-coated GNRs (CTAB-GNRs) for both cell lines. Uptake of peptide-f-GNRs and CTAB-GNRs was evaluated in two cell lines, using dark-field imaging and atomic absorption spectroscopy. Peptide-f-GNRs showed a proper cell uptake on the HeLa rather than MDA-MB-231 cell line according to the RGD (Arg-Gly-Asp) sequence in the peptide. The ability of peptide-f-GNRs to conjugate to antisense oligonucleotides (ASO) was also confirmed using zeta potential, which was due to the repeated HK (His-Lys) sequence inside the peptide. The result of these tests highlights the functionalization method as a convenient and cost-effective strategy for promising applications of targeted GNRs in the biological gene/drug delivery systems, and the repeated histidine-lysine pattern could be a useful carrier for negatively charged drug/gene delivery, too.
Graphical Abstract
Campylobacteriosis is a zoonotic infectious disease that can be mostly undiagnosed or unreported due to fastidious Campylobacter species. The aim of this study was to develop a simple, sensitive, and ...quick assay for the detection of Campylobacter spp. and taking advantage of the great sensitivity of gold nanorods (GNRs) to trace changes in the local environment and interparticle distance.
Characterized GNRs were modified by specific ssDNA probes of cadF gene. First, the biosensor was evaluated using recombinant plasmid (pTG19-T/cadF) and synthetic single-stranded 95 bp gene, followed by a collection of the extracted DNAs of the stool samples. The sensing strategy was compared by culture, PCR, and real-time PCR.
Analysis of 283 specimens showed successful detection of Campylobacter spp. in 44 cases (16%), which was comparable to culture (7%), PCR (15%), and real-time PCR (18%). In comparison with real-time PCR, the sensitivity of the biosensor was reported 88%, while the specificity test for all assays was the same (100%). However, it was not able to detect Campylobacter in 6 positive clinical samples, as compared to real-time PCR. The limit of detection was calculated to be the same for the biosensor and real-time PCR (10
copy number/mL).
Taking high speed and simplicity of this assay into consideration, the plasmonic nanobiosensor could pave the way in designing a new generation of diagnostic kits for detection of C. jejuni and C. coli species in clinical laboratories.
Candida antarctica lipase B (CALB) belongs to psychrophilic lipases which hydrolyze carboxyl ester bonds at low temperatures. There have been some features reported about cold-activity of the enzyme ...through experimental methods, whereas there is no detailed information on its mechanism of action at molecular level. Herein, a comparative molecular dynamics simulation and essential dynamics analysis have been carried out at three temperatures (5, 35 and 50 °C) to trace the dominant factors in the psychrophilic properties of CALB under cold condition. The results clearly describe the effect of temperature on CALB with meaningful differences in the flexibility of the lid region (α5 helix), covering residues 141-147. Open- closed conformations have been obtained from different sets of long-term simulations (60 ns) at 5 °C gave two reproducible distinct forms of CALB. The starting open conformation became closed immediately at 35 and 50 °C during 60 ns of simulation, while a sequential open-closed form was observed at 5 °C. These structural alterations were resulted from α5 helical movements, where the closed conformation of active site cleft was formed by displacement of both helix and its side chains. Analysis of normal mode showed concerted motions that are involved in the movement of both α5 and α10 helices. It is suggested that the functional motions needed for lypolytic activity of CALB is constructed from short-range movement of α5, accompanied by long-range movement of the domains connected to the lid region.
Engineering molecules at nano-scale is a promising approach in targeting and curing diseases. In this research, fabricated new hybrid system called nano-polyplex represents an example of the ...molecular engineering at nano-scale. Polymer of PDMAEAs with four different molecular weights were synthesized using the RAFT method, attached onto the gold nano-rod surface, which modified and produced a safe novel system with an average size less than 100 nm. The hybrid system was characterized by ultra violet-visible spectrophotometer (UV-Vis), dynamic light scattering (DLS),
H NMR, gel permeation chromatography (GPC), Fourier transform-infrared (FT-IR) spectroscopy, Zeta potential analyzer and transmission electron microscopy (TEM). Features of higher transfection and lower toxicity compared to the previously reported polyplex of PDMAEA, as well as the gold standard PEI, have been shown in all molecular weights and defined N/P ratios (10-200). The ideal physicochemical properties for escaping from the cell barriers, covering the large volume of genetic material (pDNA) and high efficiency of loading polyplexes on GNRs' surface make it an ideal carrier. The results of this effort pave way in designing a new generation of nanoparticle-based delivery systems for nucleic acid therapy and gene editing.
Gold nanorods have been nominated as propitious candidates for nanobiodiagnostic applications. Herein, a technique has been introduced for rapid visual detection of lysozyme, as its high level of ...excretion in biological fluids is a characteristic sign of leukemia and kidney disorders. Gold nanorods were biofunctionalized with lysozyme aptamer and characterized with UV–Visible and FTIR spectroscopy, zeta potential analyzer and transmission electron microscopy. Exposure of the nanoprobe to nano molar levels of lysozyme (20nmoll−1) lead to dictated aggregation of the nanostructures at ambient temperature; which was significantly improved by heat induced morphological perturbations and rapid detection by the naked eye (down to pico molar level). Qualitative analysis of Acute myeloid leukemia, Acute lymphocytic leukemia and Lymphoma blood serums showed sensitivity and specificity of the fabricated aptasensor under both temperature conditions. This report encourages utilization of heat-induced aggregation of gold nanorods as a promising nanodiagnostic technique for the emerging nanotechnologies.
Heat induced morphological perturbations of aptamer functionalized gold nanorods has been developed as a novel “lab-in-a-vial'” method for the naked-eye detection of leukemia.
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•We developed a novel “lab-in-a-vial'” technique for facile detection of lysozyme.•Fast qualitative detection capability of nanobiosensor is temperature sensitive.•Heated complex of nanoprobe and target undergoes morphological perturbations.•Heat induced aggregation of nanoprobe provides naked-eye detection of biomolecule of interest.
Custom immuno-magnetic devices are desirable tools for biomedical and biotechnological applications. Herein, surface active maghemite nanoparticles (SAMNs) are proposed as a versatile platform for ...developing tailored immuno-magnetic nano-carriers by simple wet reactions. Two examples for conjugating native and biotinylated antibodies were presented along with their successful applications in the recognition of specific foodborne pathogens. Nanoparticles were functionalized with rhodamine B isothiocyanate (RITC), leading to a fluorescent nano-conjugate, and used for binding anti-
Campylobacter fetus
antibodies (SAMN@RITC@Anti-Cf). The microorganism was selectively captured in the presence of two other
Campylobacter
species (
C. jejuni
and
C. coli
), as verified by PCR. Alternatively, SAMNs were modified with avidin, forming a biotin-specific magnetic nano-carrier and used for the immobilization of biotinylated anti-
Listeria monocytogenes
antibodies (SAMN@avidin@Anti-
Lm
). This immuno-magnetic carrier was integrated in piezoelectric quartz crystal microbalance (QCM) sensor for the detection of
L. monocytogenes
in milk, showing a detection limit of 3 bacterial cells. The present work presents a new category of customized immuno-magnetic nano-carriers as a competitive option for suiting specific applications.
Graphical abstract
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Lysozyme is a universal part of the innate immune system and is present in various bodily fluids. It is also vastly studied as a biomarker for a variety of diseases and is used in the food industry ...as a preservative. However, due to lack of a universal and precise detection method, new techniques are highly sought after for this purpose. Here, we introduce a silver nanocluster-based aptasensor to detect lysozyme with high sensitivity. The sensor consists of an RNA aptamer and a complementary DNA sequence with a silver nanocluster template. Silver nanoclusters were synthesized by reduction of silver nitrate in the presence of complementary DNA sequence and characterized by transmission electron microscopy, UV-Visible, fluorescence, and circular dichroism spectroscopy. Emission of the silver nanoclusters switched between low and high intensity based on the quenching ability of the aptamer for DNA-silver nanoclusters and the binding affinity of the aptamer for lysozyme. In the presence of the aptamer, DNA-silver nanoclusters show low fluorescence due to the hybridization of the aptamer, and hence disruption in the formation of DNA-silver nanoclusters. Upon addition of lysozyme, aptamer binding to the DNA-templated silver nanoclusters will be inhibited due to the stronger interaction between the aptamer and lysozyme. Presence of the free DNA template leads to a restored fluorescence signal of DNA-silver nanoclusters which is dependent upon the lysozyme concentration. By utilizing this strategy, the complementary DNA-templated silver nanoclusters sensor can detect concentrations of lysozyme lower than 10 nM via a signal in the visible spectral region. The proposed sensor presents valuable features such as low-cost, high sensitivity, easy fabrication, and convenient operation for detection of lysozyme.
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