A nonviral pHEMA+chitosan nanosphere-mediated high-efficiency gene delivery system

Biopolymer-based Carriers for DNA Vaccine Design

Over the last 30 years, genetically engineered DNA has been tested as novel vaccination strategy against various diseases, including human immunodeficiency virus (HIV), hepatitis B, several parasites, and cancers. However, the clinical breakthrough of the technique is confined by the low transfection efficacy and immunogenicity of the employed vaccines. Therefore, carrier materials were designed to prevent the rapid degradation and systemic clearance of DNA in the body. In this context, biopolymers are a particularly promising DNA vaccine carrier platform due to their beneficial biochemical and physical characteristics, including biocompatibility, stability, and low toxicity. This article reviews the applications, fabrication, and modification of biopolymers as carrier medium for genetic vaccines.

Antibiotic Minocycline Prevents Respiratory Syncytial Virus Infection

Treatment drugs, besides their specific activity, often have multiple effects on the body. The undesired effect of the drug may be repurposed as therapeutics, saving significant investigative time and effort. Minocycline has anti-cancer, anti-oxidant, anti-inflammatory, and anti-apoptotic properties. Presently, minocycline is also known to show anti-viral activity against Influenza virus, Japanese encephalitis virus, Simian immunodeficiency virus, Human immunodeficiency virus and West Nile virus. Here, we investigate the effect of minocycline on Respiratory syncytial virus (RSV), a common respiratory virus that causes severe mortality and morbidity in infants, children, and older adult populations. Currently, there is no effective vaccine or treatment for RSV infection; hence, there is a critical need for alternative and effective drug choices. Our study shows that minocycline reduces the RSV-mediated cytopathic effect and prevents RSV infection. This is the first study demonstrating the anti-viral activity of minocycline against RSV.

Anti-RSV Peptide-Loaded Liposomes for the Inhibition of Respiratory Syncytial Virus

Although respiratory syncytial virus (RSV) is one of the leading causes of acute respiratory tract infection in infants and adults, effective treatment options remain limited. To circumvent this issue, there is a novel approach, namely, the development of multifunctional liposomes for the delivery of anti RSV-peptides. While most of the peptides that are used for loading with the particulate delivery systems are the penetrating peptides, an alternative approach is the development of liposome-peptide systems, which are loaded with an RSV fusion peptide (RF-482), which has been designed to inhibit the RSV fusion and block infection. The results of this work have revealed that the liposomes themselves can serve as potential RSV inhibitors, whilst the anti-RSV-peptide with liposomes can significantly increase the RSV inhibition when compared with the anti-RSV peptide alone.

Design of PEI-conjugated bio-reducible polymer for efficient gene delivery

The poly(cystaminebis(acrylamide)-diaminohexane) (poly(CBA-DAH)) was designed previously as a bio-reducible efficient gene delivery carrier. However, the high weight ratio required to form the polyplexes between poly(CBA-DAH) with pDNA is still a problem that needs to be addressed. To solve this problem and increase the transfection efficiency, poly(ethylenimine) (PEI, 1.8 kDa) was conjugated to poly(CBA-DAH) via disulfide bond. The PEI conjugated poly(CBA-DAH) (PCDP) can bind with pDNA at a very low weight ratio of 0.5 and above, like PEI 25 kDa, and form the polyplexes with nano-size (102-128 nm) and positive surface charge (27-34 mV). PCDP and PCDP polyplexes had negligible cytotoxicity and indicated similar or better cellular uptake than the comparison groups such as PEI 25 kDa and Lipofectamine® polyplexes. To confirm the transfection efficiency, the plasmid DNA (pDNA) encoded with the luciferase reporter gene (gWiz-Luc) and green fluorescent protein reporter gene (GFP) were used and treated with PCDP into the A549, Huh-7, and Mia PaCa-2 cells. PCDP/pDNA polyplexes showed highest transfection efficiency in all tested cell lines. In the luciferase assay, PCDP polyplexes showed 10.2 times higher gene transfection efficiency than Lipofectamine® polyplexes in mimic in vivo conditions (30% FBS, A549 cells). The VEGF siRNA expressing plasmid (pshVEGF), which is constructed as a therapeutic gene by our previous work, was delivered by PCDP into the cancer cells. The VEGF gene expression of PCDP/pshVEGF polyplexes was dramatically lower than control and the VEGF gene silencing efficiencies of PCDP/pshVEGF (w/w; 10/1) polyplexes were 54% (A549 cells), 77% (Huh-7 cells), and 66% (Mia PaCa-2 cells). In addition, PCDP/pshVEGF had reduced cell viability rates of about 31% (A549 cells), 39% (Huh-7 cells), and 42% (Mia PaCa-2 cells) and showed better results than all comparison groups. In the transfection efficiency and VEGF silencing assay, PCDP polyplexes showed better results than poly(CBA-DAH) at 4-fold lower weight ratio. The data of all experiments demonstrate that the synthesized PCDP could be used for efficient gene delivery and could be widely applied.

Potential applications and human biosafety of nanomaterials used in nanomedicine

With the rapid development of nanotechnology, potential applications of nanomaterials in medicine have been widely researched in recent years. Nanomaterials themselves can be used as image agents or therapeutic drugs, and for drug and gene delivery, biological devices, nanoelectronic biosensors or molecular nanotechnology. As the composition, morphology, chemical properties, implant sites as well as potential applications become more and more complex, human biosafety of nanomaterials for clinical use has become a major concern. If nanoparticles accumulate in the human body or interact with the body molecules or chemical components, health risks may also occur. Accordingly, the unique chemical and physical properties, potential applications in medical fields, as well as human biosafety in clinical trials are reviewed in this study. Finally, this article tries to give some suggestions for future work in nanomedicine research. Copyright © 2017 John Wiley & Sons, Ltd.

Synthetic Biodegradable Microparticle and Nanoparticle Vaccines against the Respiratory Syncytial Virus

Synthetic biodegradable microparticle and nanoparticle platform technology provides the opportunity to design particles varying in composition, size, shape and surface properties for application in vaccine development. The use of particle vaccine formulations allows improvement of antigen stability and immunogenicity while allowing targeted delivery and slow release. This technology has been design to develop novel vaccines against the respiratory syncytial virus (RSV), the leading cause of lower respiratory tract infection in infants. In the last decade, several nano- and micro-sized RSV vaccine candidates have been developed and tested in animal models showing promising results. This review provides an overview of recent advances in prophylactic particle vaccines for RSV and the multiple factors that can affect vaccine efficacy.

Gold nanorods inhibit respiratory syncytial virus by stimulating the innate immune response

Respiratory syncytial virus (RSV) causes severe pneumonia and bronchiolitis in infants, children and older adults. The use of metallic nanoparticles as potential therapeutics is being explored against respiratory viruses like Influenza, Parainfluenza and Adenovirus. In this study, we showed that gold nanorods (GNRs) inhibit RSV in HEp-2 cells and BALB/c mice by 82% and 56%, respectively. The RSV inhibition correlated with marked upregulated antiviral genes due to GNR mediated TLR, NOD-like receptor and RIG-I-like receptor signaling pathways. Transmission electron microscopy of lungs showed GNRs in the endocytotic vesicles and histological analyses indicated infiltration by neutrophils, eosinophils and monocytes correlating with clearance of RSV. In addition, production of cytokines and chemokines in the lungs indicates recruitment of immune cells to counter RSV replication. To our knowledge, this is the first in vitro and in vivo report that provides possible antiviral mechanisms of GNRs against RSV.

Immunogenicity of RSV F DNA Vaccine in BALB/c Mice

Respiratory syncytial virus (RSV) causes severe acute lower respiratory tract disease leading to numerous hospitalizations and deaths among the infant and elderly populations worldwide. There is no vaccine or a less effective drug available against RSV infections. Natural RSV infection stimulates the Th1 immune response and activates the production of neutralizing antibodies, while earlier vaccine trials that used UV-inactivated RSV exacerbated the disease due to the activation of the allergic Th2 response. With a focus on Th1 immunity, we developed a DNA vaccine containing the native RSV fusion (RSV F) protein and studied its immune response in BALB/c mice. High levels of RSV specific antibodies were induced during subsequent immunizations. The serum antibodies were able to neutralize RSV in vitro. The RSV inhibition by sera was also shown by immunofluorescence analyses. Antibody response of the RSV F DNA vaccine showed a strong Th1 response. Also, sera from RSV F immunized and RSV infected mice reduced the RSV infection by 50% and 80%, respectively. Our data evidently showed that the RSV F DNA vaccine activated the Th1 biased immune response and led to the production of neutralizing antibodies, which is the desired immune response required for protection from RSV infections.

Gold nanorods inhibit respiratory syncytial virus by stimulating the innate immune response

Respiratory syncytial virus (RSV) causes severe pneumonia and bronchiolitis in infants, children and older adults. The use of metallic nanoparticles as potential therapeutics is being explored against respiratory viruses like Influenza, Parainfluenza and Adenovirus. In this study, we showed that gold nanorods (GNRs) inhibit RSV in HEp-2 cells and BALB/c mice by 82% and 56%, respectively. The RSV inhibition correlated with marked upregulated antiviral genes due to GNR mediated TLR, NOD-like receptor and RIG-I-like receptor signaling pathways. Transmission electron microscopy of lungs showed GNRs in the endocytotic vesicles and histological analyses indicated infiltration by neutrophils, eosinophils and monocytes correlating with clearance of RSV. In addition, production of cytokines and chemokines in the lungs indicates recruitment of immune cells to counter RSV replication. To our knowledge, this is the first in vitro and in vivo report that provides possible antiviral mechanisms of GNRs against RSV.

Transactivator of transcription (TAT) peptide- chitosan functionalized multiwalled carbon nanotubes as a potential drug delivery vehicle for cancer therapy

Carbon nanotube (CNT)-based drug delivery vehicles might find great potential in cancer therapy via the combination of chemotherapy with photothermal therapy due to the strong optical absorbance of CNTs in the near-infrared region. However, the application of CNTs in cancer therapy was considerably constrained by their lack of solubility in aqueous medium, as well as the cytotoxicity caused by their hydrophobic surface. Intracellular delivery efficiency is another factor determining the application potential of CNTs in cancer therapy. In the present study, low-molecular-weight chitosan conjugated with transactivator of transcription (TAT) peptide was used for noncovalent functionalization of multiwalled carbon nanotubes (MWCNTs), aiming at providing a more efficient drug delivery vehicle for cancer therapy. The TAT–chitosan-conjugated MWCNTs (MWCNTs-TC) were further investigated for their water solubility, cytotoxicity, cell-penetrating capability, and accumulation in tumor. It was found that MWCNTs-TC were essentially nontoxic with satisfying water solubility, and they were more efficient in terms of cancer-targeted intracellular transport both in vitro and in vivo as compared with chitosan-modified MWCNTs (MWCNTs-CS), suggesting the great application potential of MWCNTs-TC in cancer therapy.

Novel pegylated silver coated carbon nanotubes kill Salmonella but they are non-toxic to eukaryotic cells

BACKGROUND

Resistance of food borne pathogens such as Salmonella to existing antibiotics is of grave concern. Silver coated single walled carbon nanotubes (SWCNTs-Ag) have broad-spectrum antibacterial activity and may be a good treatment alternative. However, toxicity to human cells due to their physico-chemical properties is a serious public health concern. Although pegylation is commonly used to reduce metal nanoparticle toxicity, SWCNTs-Ag have not been pegylated as yet, and the effect of pegylation of SWCNTs-Ag on their anti-bacterial activity and cell cytotoxicity remains to be studied. Further, there are no molecular studies on the anti-bacterial mechanism of SWCNTs-Ag or their functionalized nanocomposites.

MATERIALS AND METHODS

In this study we created novel pegylated SWCNTS-Ag (pSWCNTs-Ag), and employed 3 eukaryotic cell lines to evaluate their cytotoxicity as compared to plain SWCNTS-Ag. Simultaneously, we evaluated their antibacterial activity on Salmonella enterica serovar Typhimurium (Salmonella Typhimurium) by the MIC and growth curve assays. In order to understand the possible mechanisms of action of both SWCNTs-Ag and pSWCNTs-Ag, we used electron microscopy (EM) and molecular studies (qRT-PCR).

RESULTS

pSWCNTs-Ag inhibited Salmonella Typhimurium at 62.5 μg/mL, while remaining non-toxic to human cells. By comparison, plain SWCNTs-Ag were toxic to human cells at 62.5 μg/mL. EM analysis revealed that bacteria internalized either of these nanocomposites after the outer cell membranes were damaged, resulting in cell lysis or expulsion of cytoplasmic contents, leaving empty ghosts. The expression of genes regulating the membrane associated metabolic transporter system (artP, dppA, and livJ), amino acid biosynthesis (trp and argC) and outer membrane integrity (ompF) protiens, was significantly down regulated in Salmonella treated with both pSWCNTs-Ag and SWCNTs-Ag. Although EM analysis of bacteria treated with either SWCNTs-Ag or pSWCNTs-Ag revealed relatively similar morphological changes, the expression of genes regulating the normal physiological processes of bacteria (ybeF), quorum sensing (sdiA), outer membrane structure (safC), invasion (ychP) and virulence (safC, ychP, sseA and sseG) were exclusively down regulated several fold in pSWCNTs-Ag treated bacteria.

CONCLUSIONS

Altogether, the present data shows that our novel pSWCNTs-Ag are non-toxic to human cells at their bactericidal concentration, as compared to plain SWCNTS-Ag. Therefore, pSWCNTs-Ag may be safe alternative antimicrobials to treat foodborne pathogens.

Cross-linked polyethylenimine-tripolyphosphate nanoparticles for gene delivery

The high transfection efficiency of polyethylenimine (PEI) makes it an attractive potential nonviral genetic vector for gene delivery and therapy. However, the highly positive charge of PEI leads to cytotoxicity and limits its application. To reduce the cytotoxicity of PEI, we prepared anion-enriched nanoparticles that combined PEI with tripolyphosphate (TPP). We then characterized the PEI-TPP nanoparticles in terms of size, zeta potential, and Fourier-transform infrared (FTIR) spectra, and assessed their transfection efficiency, cytotoxicity, and ability to resist deoxyribonuclease (DNase) I digestion. The cellular uptake of PEI-TPP with phosphorylated internal ribosome entry site–enhanced green fluorescent protein C1 or FAM (fluorouracil, Adriamycin [doxorubicin] and mitomycin)-labeled small interfering ribonucleic acids (siRNAs) was monitored by fluorescence microscopy and confocal laser microscopy. The efficiency of transfected delivery of plasmid deoxyribonucleic acid (DNA) and siRNA in vitro was 1.11- to 4.20-fold higher with the PEI-TPP particles (7.6% cross-linked) than with the PEI, at all N:P ratios (nitrogen in PEI to phosphorus in DNA) tested. The cell viability of different cell lines was more than 90% at the chosen N:P ratios of PEI-TPP/DNA complexes. Moreover, PEI-TPP nanoparticles resisted digestion by DNase I for more than 2 hours. The time-dependent absorption experiment showed that 7.6% of cross-linked PEI-TPP particles were internalized by 293T cells within 1 hour. In summary, PEI-TPP nanoparticles effectively transfected cells while conferring little or no toxicity, and thus have potential application in gene delivery.

Recent advances in diagnosis, prevention, and treatment of human respiratory syncytial virus

Human respiratory syncytial virus (RSV) is a common cause of respiratory infection in infants and the elderly, leading to significant morbidity and mortality. The interdisciplinary fields, especially biotechnology and nanotechnology, have facilitated the development of modern detection systems for RSV. Many anti-RSV compounds like fusion inhibitors and RNAi molecules have been successful in laboratory and clinical trials. But, currently, there are no effective drugs for RSV infection even after decades of research. Effective diagnosis can result in effective treatment, but the progress in both of these facets must be concurrent. The development in prevention and treatment measures for RSV is at appreciable pace, but the implementation into clinical practice still seems a challenge. This review attempts to present the promising diverse research approaches and advancements in the area of diagnosis, prevention, and treatment that contribute to RSV management.