Delivery Of Various Bioactive Molecules Research Articles

A dynamic DNA tetrahedron framework for active targeting.

An active targeting strategy-enabled DNA tetrahedron delivery vehicle could facilitate stable drug encapsulation and stimuli-responsive on-demand release, building a universal platform for different drug delivery requirements. Owing to the excellent biocompatible nature, programmability and remarkable cell and tissue permeability, the tetrahedral DNA nanostructure (TDN) has proven its value in the delivery of various bioactive molecules. We previously described this as a static multifunctional complex in our earlier protocol. However, static structures and passive targeting behavior might introduce off-target effects under complicated biological conditions. Therefore, in this Protocol Extension, we present a major update of the TDN delivery vehicle enabling an active targeting strategy to be used for stimuli-sensitive conformation changes and on-site cargo release, which could avoid drawbacks, including complex and time-consuming fabrication processes and undetermined cell penetration ability of other DNA-based delivery vehicles. Upon exquisite design of TDN size based on cargo type, one-pot annealing is applied to fabricate the Tiamat-designed TDN exoskeleton. Then the design of the dynamic DNA apparatus can be based on the target and environmental stimuli, including DNA strand hybridization-based and pH-sensitive DNA apparatus, and careful titration of strand lengths and mismatches is achieved using polyacrylamide and agarose gel electrophoresis, or fluorophore modifications. Finally, cargo loading strategies are designed, including site and stand titration and cargo encapsulation verification. The dynamic structures show promising targetability and effectiveness in antitumor and anti-inflammatory treatment in vitro and in vivo. Assembly and characterization in the lab takes ~5 d, and the timing for the verification of biostability and biological applications depends on the uses.

An Advanced Review on Resealed Erythrocytes

Now a days there are numerous applications have been proposed for the use of resealed erythrocytes as carrier for drugs, enzyme replacement therapy etc. Until other carrier systems come of age, resealed erythrocytes technology will remain an active field for the further research. The use of resealed erythrocytes shows potential for a safe and effective delivery of various bioactive molecules for effective targeting. In coming future, erythrocyte based drug delivery system with their capability to afford controlled and site specific drug delivery have been developed for disease management. Erythrocyte carriers are “Nano devices in the field of Nanotechnology”. A large amount of valuable work is needed so as to utilize the potentials of erythrocytes in passive as well as active targeting of drugs in diseases like cancer. At present erythrocytes are most effective carriers in novel drug delivery systems considering their tremendous potential. Hence the present article is reviewed about method of drug loading, evaluation and applications of RSE.

Electrospun Nanofibers for Tissue Engineering with Drug Loading and Release.

Electrospinning technologies have been applied in the field of tissue engineering as materials, with nanoscale-structures and high porosity, can be easily prepared via this method to bio-mimic the natural extracellular matrix (ECM). Tissue engineering aims to fabricate functional biomaterials for the repairment and regeneration of defective tissue. In addition to the structural simulation for accelerating the repair process and achieving a high-quality regeneration, the combination of biomaterials and bioactive molecules is required for an ideal tissue-engineering scaffold. Due to the diversity in materials and method selection for electrospinning, a great flexibility in drug delivery systems can be achieved. Various drugs including antibiotic agents, vitamins, peptides, and proteins can be incorporated into electrospun scaffolds using different electrospinning techniques and drug-loading methods. This is a review of recent research on electrospun nanofibrous scaffolds for tissue-engineering applications, the development of preparation methods, and the delivery of various bioactive molecules. These studies are based on the fabrication of electrospun biomaterials for the repair of blood vessels, nerve tissues, cartilage, bone defects, and the treatment of aneurysms and skin wounds, as well as their applications related to oral mucosa and dental fields. In these studies, due to the optimal selection of drugs and loading methods based on electrospinning, in vitro and in vivo experiments demonstrated that these scaffolds exhibited desirable effects for the repair and treatment of damaged tissue and, thus, have excellent potential for clinical application.

Addition of thrombin reduces the recovery of extracellular vesicles from blood plasma.

Extracellular vesicles (EVs) are widely studied as a system of intercellular communication, as markers of various diseases, as well as a vehicle for delivery of various bioactive molecules to various cells. Investigation of EVs’ structure and function requires their isolation and precise quantification. However, in the current literature, there are significant discrepancies in the estimated numbers of EVs in different body fluids. In part, this discrepancy is due to the difference in EVs isolation protocols used by different investigators. A common protocol that includes ExoQuick™ is often used to isolate EVs from body fluids and culture medium. Here, we show that in the case of isolation of EVs from blood, thrombin should be omitted from the protocol as clots formed due to the thrombin-triggered coagulation may entrap many EVs thus leading to the underestimation of their numbers.

Controlled delivery of bPEI–niclosamide complexes by PEO nanofibers and evaluation of its anti-neoplastic potentials

Since the turn of the 21st century, nanofiber based drug delivery systems have evolved drastically to attain controlled and sustained delivery of various bioactive molecules. In spite of such efforts, the tangible interface existing between the target cells and the drug molecules could not be narrowed down. This drawback has been overcome in this work by realizing nanofiber based scaffold for delivery of polymer–drug complexes rather than just the drug. In course with this, in the present study a differentially cross-linkable bPEI-PEO (branched-polyethylenimine-poly(ethylene oxide)) based nanofiber is fabricated for tunable delivery of bPEI–niclosamide complexes. Hydrophilic bPEI–niclosamide complexes are pre-synthesized and stabilized by crosslinking agent, which were then incorporated into bPEI-PEO nanofibers by electrospinning. The niclosamide loaded nanofibers by virtue of bPEI moieties presence were then cross-linked to different degrees which in turn altered bPEI–niclosamide release profile. The release kinetics of bPEI–niclosamide complexes from nanofibers was elucidated further by Korsmeyer-Peppas model. Apart from this, the versatile nature of bPEI-PEO nanofibers was also validated for different drug loading concentration and extent of crosslinking. The fibers antitumor efficacy was then assessed against A549 (Non-small cell lung cancer cells) and U-87 MG (glioblastoma cells) at two different time points (at 48h and 96h) in order to realize the importance of release profile in manifestation of different therapeutic outcomes. Thus, this work endows niclosamide a new life for anticancer application which has remained elusive till date due to its hydrophobic nature.

Molecular interplays involved in the cellular uptake of octaarginine on cell surfaces and the importance of syndecan-4 cytoplasmic V domain for the activation of protein kinase Cα

Arginine-rich cell-penetrating peptides (CPPs) are promising carriers for the intracellular delivery of various bioactive molecules. However, many ambiguities remain about the molecular interplays on cell surfaces that ultimately lead to endocytic uptake of CPPs. By treatment of cells with octaarginine (R8), enhanced clustering of syndecan-4 on plasma membranes and binding of protein kinase Cα (PKCα) to the cytoplasmic domain of syndecan-4 were observed; these events potentially lead to the macropinocytic uptake of R8. The cytoplasmic V domain of syndecan-4 made a significant contribution to the cellular uptake of R8, whereas the cytoplasmic C1 and C2 domains were not involved in the process.

Acylation of octaarginine: Implication to the use of intracellular delivery vectors

Cell-penetrating peptides (CPPs) have the ability to efficiently internalize into cells and thus have been used as a vector for the intracellular delivery of various bioactive molecules. The introduction of a hydrophobic core to CPPs may increase their interaction with membranes and facilitate their translocation into cells. While the usefulness of acylated oligoarginine to gene and siRNA delivery has been largely reported, little information is available about their use for the delivery of small molecular-weight compounds, peptides and proteins. In this report, we employed octaarginine (R8) as a typical arginine-rich CPP and evaluated the effect of acylation using butanoic, hexanoic and decanoic acids on its capacity as a delivery vector. Hexanoyl octaarginine (C6R8-Alexa) showed the highest efficiency of cellular uptake of the studied variants, ten times higher than R8-Alexa. C6R8-Alexa also produced a diffuse cytosolic distribution. On the other hand, a less significant effect of C6R8 over R8 was observed for the delivery of proteins, suggesting that the advantage of C6R8 may be obtained during the delivery of relatively small molecular-weight compounds. Although less prominent than at 37 °C, a significant cytosolic distribution of C6R8-Alexa was observed at 4 °C, and this suggested the potential ability of the C6R8 peptide for direct penetration through plasma membranes.

Enhanced intracellular delivery using arginine-rich peptides by the addition of penetration accelerating sequences (Pas)

Cell penetrating peptides (CPPs), including arginine-rich peptides, are attractive tools for the intracellular delivery of various bioactive molecules with a low membrane permeability. We showed that the accelerated intracellular delivery of arginine-rich peptides was achieved by the addition of a short peptide segment (penetration accelerating sequence, Pas) to arginine-rich CPPs. The cytosolic release of the Pas-attached arginine-rich CPPs was observed within 5 min after the treatment of the cells with the peptides even in the presence of serum. Effectiveness of the Pas segment in the intracellular delivery of bioactive peptides using arginine-rich CPPs was exemplified through the enhanced growth inhibition activity of the malignant glioma cells by a retro-inverso peptide derived from the p53 C-terminal 22-amino-acid segment (positions 361–382).

Acid wash in determining cellular uptake of Fab/cell‐permeating peptide conjugates

Successful intracellular delivery of various bioactive molecules has been reported using cell-permeating peptides (CPPs) as delivery vectors. To determine the effects of CPPs on the cellular uptake of immunoglobulin Fab fragment, conjugates of a radio-iodinated Fab fragment with CPPs (CPP-(125)I-Fab) derived from HIV-1 TAT, HIV-1 REV, and Antennapedia (ANP) were prepared. These vectors are rich in basic amino acids, and their strong adsorption on cell surfaces often results in overestimation of internalized peptides. Cell wash with an acidic buffer (0.2M glycine-0.15M NaCl, pH 3.0) was thus employed in this study to remove cell-surface adsorbed CPP-(125)I-Fab conjugates. This procedure enabled clearer understanding of the methods of internalization of CPP-(125)I-Fab conjugates. The kinetics of internalization of REV-(125)I-Fab conjugate was rapid, and a considerable fraction of REV-(125)I-Fab was taken up by HeLa cells as early as 5 min after administration. It was also shown that cellular uptake of these conjugates was significantly inhibited in the presence of endocytosis/ macropinocytosis inhibitors, in the order REV-(125)I-Fab > or = TAT-(125)I-Fab > or = ANP-(125)I-Fab; this order was the same as for effectiveness of intracellular delivery. Simultaneous cell washing with phosphate-buffered saline (PBS) and this acidic buffer effectively separated the internalized conjugates from the cell-surface-adsorbed ones, and considerable differences were observed in these amounts dependent on the employed CPPs.