Plant protein-based hydrophobic fine and ultrafine carrier particles in drug delivery systems.

For thousands of years, plants and their products have been used as the mainstay of medicinal therapy. In recent years, besides attempts to isolate the active ingredients of medicinal plants, other new applications of plant products, such as their use to prepare drug delivery vehicles, have been discovered. Nanobiotechnology is a branch of pharmacology that can provide new approaches for drug delivery by the preparation of biocompatible carrier nanoparticles (NPs). In this article, we review recent studies with four important plant proteins that have been used as carriers for targeted delivery of drugs and genes. Zein is a water-insoluble protein from maize; Gliadin is a 70% alcohol-soluble protein from wheat and corn; legumin is a casein-like protein from leguminous seeds such as peas; lectins are glycoproteins naturally occurring in many plants that recognize specific carbohydrate residues. NPs formed from these proteins show good biocompatibility, possess the ability to enhance solubility, and provide sustained release of drugs and reduce their toxicity and side effects. The effects of preparation methods on the size and loading capacity of these NPs are also described in this review.

Noble metal nanoparticles in biosensors: recent studies and applications.

The aim of this review is to cover advances in noble metal nanoparticle (MNP)-based biosensors and to outline the principles and main functions of MNPs in different classes of biosensors according to the transduction methods employed. The important biorecognition elements are enzymes, antibodies, aptamers, DNA sequences, and whole cells. The main readouts are electrochemical (amperometric and voltametric), optical (surface plasmon resonance, colorimetric, chemiluminescence, photoelectrochemical, etc.) and piezoelectric. MNPs have received attention for applications in biosensing due to their fascinating properties. These properties include a large surface area that enhances biorecognizers and receptor immobilization, good ability for reaction catalysis and electron transfer, and good biocompatibility. MNPs can be used alone and in combination with other classes of nanostructures. MNP-based sensors can lead to significant signal amplification, higher sensitivity, and great improvements in the detection and quantification of biomolecules and different ions. Some recent examples of biomolecular sensors using MNPs are given, and the effects of structure, shape, and other physical properties of noble MNPs and nanohybrids in biosensor performance are discussed.

Bacteriophages and phage-inspired nanocarriers for targeted delivery of therapeutic cargos.

The main goal of drug delivery systems is to target therapeutic cargoes to desired cells and to ensure their efficient uptake. Recently a number of studies have focused on designing bio-inspired nanocarriers, such as bacteriophages, and synthetic carriers based on the bacteriophage structure. Bacteriophages are viruses that specifically recognize their bacterial hosts. They can replicate only inside their host cell and can act as natural gene carriers. Each type of phage has a particular shape, a different capacity for loading cargo, a specific production time, and their own mechanisms of supramolecular assembly, that have enabled them to act as tunable carriers. New phage-based technologies have led to the construction of different peptide libraries, and recognition abilities provided by novel targeting ligands. Phage hybridization with non-organic compounds introduces new properties to phages and could be a suitable strategy for construction of bio-inorganic carriers. In this review we try to cover the major phage species that have been used in drug and gene delivery systems, and the biological application of phages as novel targeting ligands and targeted therapeutics.

Microfluidic systems for stem cell-based neural tissue engineering.

Neural tissue engineering aims at developing novel approaches for the treatment of diseases of the nervous system, by providing a permissive environment for the growth and differentiation of neural cells. Three-dimensional (3D) cell culture systems provide a closer biomimetic environment, and promote better cell differentiation and improved cell function, than could be achieved by conventional two-dimensional (2D) culture systems. With the recent advances in the discovery and introduction of different types of stem cells for tissue engineering, microfluidic platforms have provided an improved microenvironment for the 3D-culture of stem cells. Microfluidic systems can provide more precise control over the spatiotemporal distribution of chemical and physical cues at the cellular level compared to traditional systems. Various microsystems have been designed and fabricated for the purpose of neural tissue engineering. Enhanced neural migration and differentiation, and monitoring of these processes, as well as understanding the behavior of stem cells and their microenvironment have been obtained through application of different microfluidic-based stem cell culture and tissue engineering techniques. As the technology advances it may be possible to construct a "brain-on-a-chip". In this review, we describe the basics of stem cells and tissue engineering as well as microfluidics-based tissue engineering approaches. We review recent testing of various microfluidic approaches for stem cell-based neural tissue engineering.

Albumin nanostructures as advanced drug delivery systems.

INTRODUCTION: One of the biggest impacts that the nanotechnology has made on medicine and biology, has been in the area of drug delivery systems (DDSs). Many drugs suffer from serious problems concerning insolubility, instability in biological environments, poor uptake into cells and tissues, sub-optimal selectivity for targets and unwanted side effects. Nanocarriers can be designed as DDSs to overcome many of these drawbacks. One of the most versatile building blocks to prepare these nanocarriers is the ubiquitous, readily available and inexpensive protein, serum albumin. Areas covered: This review covers the use of different types of albumin (human, bovine, rat, and chicken egg) to prepare nanoparticle and microparticle-based structures to bind drugs. Various methods have been used to modify the albumin structure. A range of targeting ligands can be attached to the albumin that can be recognized by specific cell receptors that are expressed on target cells or tissues. Expert opinion: The particular advantages of albumin used in DDSs include ready availability, ease of chemical modification, good biocompatibility, and low immunogenicity. The regulatory approvals that have been received for several albumin-based therapeutic agents suggest that this approach will continue to be successfully explored.

Carbon nanotubes part I: preparation of a novel and versatile drug-delivery vehicle.

INTRODUCTION: It is 23 years since carbon allotrope known as carbon nanotubes (CNT) was discovered by Iijima, who described them as "rolled graphite sheets inserted into each other". Since then, CNTs have been studied in nanoelectronic devices. However, CNTs also possess the versatility to act as drug- and gene-delivery vehicles. AREAS COVERED: This review covers the synthesis, purification and functionalization of CNTs. Arc discharge, laser ablation and chemical vapor deposition are the principle synthesis methods. Non-covalent functionalization relies on attachment of biomolecules by coating the CNT with surfactants, synthetic polymers and biopolymers. Covalent functionalization often involves the initial introduction of carboxylic acids or amine groups, diazonium addition, 1,3-dipolar cycloaddition or reductive alkylation. The aim is to produce functional groups to attach the active cargo. EXPERT OPINION: In this review, the feasibility of CNT being used as a drug-delivery vehicle is explored. The molecular composition of CNT is extremely hydrophobic and highly aggregation-prone. Therefore, most of the efforts towards drug delivery has centered on chemical functionalization, which is usually divided in two categories; non-covalent and covalent. The biomedical applications of CNT are growing apace, and new drug-delivery technologies play a major role in these efforts.