Peptide nanostructures-based delivery of DNA nanomaterial therapeutics for regulating gene expression.

Self-assembled branched DNA (bDNA) nanomaterials have exhibited their functionality in various biomedical and diagnostic applications. However, the anionic cellular membrane has restricted the movement of bDNA nanostructures. Recently, amphiphilic peptides have been investigated as cationic delivery agents for nucleic acids. Herein, we demonstrate a strategy for delivering functional bDNA nanomaterials into mammalian cells using self-assembled linear peptides. In this study, antisense oligonucleotides of vascular endothelial growth factor (VEGF) were inserted in the overhangs of bDNAs. Novel linear peptides have been synthesized and the peptide-bound bDNA complex formation was examined using various biophysical experiments. Interestingly, the W4R4-bound bDNAs were found to be exceptionally stable against DNase I compared to other complexes. The delivery of fluorescent-labeled bDNAs into the mammalian cells confirmed the potential of peptide transporters. Furthermore, the functional efficacy of the peptide-bound bDNAs has been examined through RT-PCR and western blot analysis. The observed results revealed that W4R4 peptides exhibited excellent internalization of antisense bDNAs and significantly suppressed (3- to 4-fold) the transcripts and translated product of VEGF compared to the control. In summary, the results highlight the potential use of peptide-based nanocarrier for delivering bDNA nanostructures to regulate the gene expression in cell lines.

Cyclic peptides nanospheres: A '2-in-1' self-assembled delivery system for targeting nucleus and cytoplasm.

Vascular endothelial growth factor (VEGF) is considered as one of the vital growth factors for angiogenesis, which is primarily responsible for the progress and maintenance of new vascular network in tumor. Numerous studies report that inhibition of VEGF-induced angiogenesis is a potent technique for cancer suppression. Recently, RNA interference, especially small interfering RNA (siRNA) signified a promising approach to suppress the gene expression. However, the clinical implementation of biological macromolecules such as siRNA is significantly limited because of stability and bioavailability issues. Herein, self-assembled peptide nanospheres have been generated from L,L-cyclic peptides using hydrophobic (Trp), positively charged (Arg) and cysteine (Cys) amino acid residues and demonstrated as vehicles for intracellular delivery of VEGF siRNA and VEGF antisense oligonucleotide. Formation of peptide nanostructures is confirmed by HR-TEM, AFM, SEM and DLS analysis. Possible mechanism of self-assembly of the cyclic peptides and their binding with macromolecules are demonstrated by in-silico analysis. Gel electrophoresis reveals that the newly generated peptide based organic materials exhibit strong binding affinity toward siRNAs / antisense oligonucleotides (ASOs) at optimum concentration. Flow cytometry and confocal microscopy results confirm the efficiency of the new biomaterials toward the intracellular delivery of fluorescent labeled siRNA / ASOs. Furthermore, VEGF expression evaluated by western blot and RT-PCR upon the delivery of functional VEGF siRNA/ASOs suggests that very low concentrations of VEGF siRNA/ASOs cause significant gene knockdown at protein and mRNA levels, respectively.

A comprehensive review on the applications of nano-biosensor-based approaches for non-communicable and communicable disease detection.

The outstretched applications of biosensors in diverse domains has become the reason for their attraction for scientific communities. Because they are analytical devices, they can detect both quantitative and qualitative biological components through the generation of detectable signals. In the recent past, biosensors witnessed significant changes and developments in their design as well as features. Nanotechnology has revolutionized sensing phenomena by increasing biodiagnostic capacity in terms of specificity, size, and cost, resulting in exceptional sensitivity and flexibility. The steep increase of non-communicable diseases across the world has emerged as a matter of concern. In parallel, the abrupt outbreak of communicable diseases poses a serious threat to mankind. For decreasing the morbidity and mortality associated with various communicable and non-communicable diseases, early detection and subsequent treatment are indispensable. Detection of different biological markers generates quantifiable signals that can be electrochemical, mass-based, optical, thermal, or piezoelectric. Speculating on the incumbent applicability and versatility of nano-biosensors in large disciplines, this review highlights different types of biosensors along with their components and detection mechanisms. Moreover, it deals with the current advancements made in biosensors and the applications of nano-biosensors in detection of various non-communicable and communicable diseases, as well as future prospects of nano-biosensors for diagnostics.

Emerging Molecular Prospective of SARS-CoV-2: Feasible Nanotechnology Based Detection and Inhibition.

The rapid dissemination of SARS-CoV-2 demonstrates how vulnerable it can make communities and is why it has attained the status of global pandemic. According to the estimation from Worldometer, the SARS-CoV-2 affected cases and deaths are exponentially increasing worldwide, marking the mortality rate as ∼3.8% with no probability of its cessation till now. Despite massive attempts and races among scientific communities in search of proper therapeutic options, the termination of this breakneck outbreak of COVID-19 has still not been made possible. Therefore, this review highlights the diverse molecular events induced by a viral infection, such as autophagy, unfolded protein response (UPR), and inflammasome, illustrating the intracellular cascades regulating viral replication inside the host cell. The SARS-CoV-2-mediated endoplasmic reticulum stress and apoptosis are also emphasized in the review. Additionally, host's immune response associated with SARS-CoV-2 infection, as well as the genetic and epigenetic changes, have been demonstrated, which altogether impart a better understanding of its epidemiology. Considering the drawbacks of available diagnostics and medications, herein we have presented the most sensitive nano-based biosensors for the rapid detection of viral components. Moreover, conceptualizing the viral-induced molecular changes inside its target cells, nano-based antiviral systems have also been proposed in this review.

Peptide generated anisotropic gold nanoparticles as efficient siRNA vectors.

Based on the cell penetrating ability of tryptophan-containing peptides, eight linear hexapeptides have been designed, synthesized and explored their efficiency toward the synthesis of gold nanoparticles under sunlight. The peptide generated gold nanoparticles (LP-GNPs) have been characterized by UV-visible spectroscopy, Transmission Electron Microscopy (TEM) and Dynamic Light Scattering (DLS) techniques. The binding ability of LP-GNPs toward siRNA, evaluated by gel electrophoresis indicates that sequence-selective-GNPs without any surface modifications exhibit strong affinity toward negatively charged biomolecules. Cellular uptake studies suggest that LP-GNPs exhibit significant uptake of fluorescence-labeled siRNA inside the cells as evidenced from Fluorescence Microscopy. In vitro gene silencing efficiency using newly generated GNPs revealed that above mentioned LP-GNPs efficiently down-regulate the level of GAPGH gene in colon cancer cells. Comparative gene silencing efficiency results indicate that anisotropic LP7-GNPs exhibit comparable efficacy to other existing carrier systems, such as Lipofectamine 2000 in presence of serum, mimicking in-vivo system. In conclusion, our results demonstrate that peptide-GNPs based delivery system for siRNA emerges to be effective to deliver RNAi therapeutics, uncovering new avenue in oncotherapy.

Cyclic peptide-based nanostructures as efficient siRNA carriers.

RNA interference shows a great strategy for biological studies; however, delivering of small interfering RNA (siRNA) remains challenging. Although several delivery vehicles, including cell-penetrating peptides, have been developed, their implementation is often restricted because of their endosomal entrapment. Herein, we report the formation of self-assembled nanostructures from rationally designed cyclic peptides and explore them for efficient delivery of functional biomacromolecules such as siRNA into mammalian cells. The newly obtained soft materials make stable complexes with siRNAs, thereby increasing their stability and deliver fluorescent labelled siRNA inside the cells as evident from confocal microscopy analysis. Flow cytometry analysis reveals that significant uptake of FAM-siRNA occurs in the presence of peptide nanostructures compared with siRNA alone. Peptide nanostructure-mediated delivery of very low concentration of siRNA causes significant knockdown of the target gene as observed at protein level by Western blot analysis, which is comparable to lipofectamine, commercially available transfection agent.

Rapid colorimetric sensing of gadolinium by EGCG-derived AgNPs: the development of a nanohybrid bioimaging probe.

Polyphenol functionalized silver nanoparticles (AgNPs) have been developed and demonstrated as colorimetric sensors for the selective detection of gadolinium. The newly obtained AgNP-Gd3+ conjugates exhibit high aqueous dispersibility and excitation dependent fluorescence emission. The conjugates offer multicolor bioimaging potential owing to their excellent luminescence properties.

Photo-bioreduction of Ag+ ions towards the generation of multifunctional silver nanoparticles: Mechanistic perspective and therapeutic potential.

In this article, light induced plant extract mediated one pot synthesis of silver nanoparticles (AgNPs) has been demonstrated and potential mechanistic insight in the synthesis has been investigated. Bioactive molecules containing medicinal plant Cassytha filiformis has been explored for the synthesis of silver nanoparticles. The as-synthesized silver nanoparticles were characterized by various analytical techniques including Ultraviolet-visible spectroscopy (UV-Vis), High Resolution Transmission Electron Microscopy (HR-TEM), Dynamic Light Scattering (DLS) and Fourier Transform Infrared Spectroscopy (FT-IR). Among different light sources (sunlight, room light, UV) applied the sunlight was found to be efficient external stimuli to induce rapid synthesis of AgNPs at room temperature. Modified DPPH assay indicated that polyphenolic compounds were most likely involved in the synthesis of AgNPs. Possible molecule responsible for the synthesis of AgNPs was identified, purified and characterized. Potential biomedical applications such as antibacterial, antifungal and anticancer activities of AgNPs have been evaluated. Irrespective of nature of pathogenic strains nanoparticles exhibited significant antibacterial activities against Gram positive (Streptococcus aureus) and Gram negative (Escherichia coli) bacterial pathogens. It showed higher activity on E. coli than on S. aureus. Distinct antifungal activity (MIC=5.244µg/ml) and remarkable anticancer activity (IC50=10µg/ml) was found against Candida albicans and HCT116 (colorectal carcinoma) cells, respectively. Taken together, these findings suggested that light induced plant generated silver nanoparticles could be used for various biomedical purposes.