Ultrasound-Triggered Controlled Drug Delivery and Biosensing Using Silica Nanotubes

Silica nanotubes (SNTs) have been demonstrated here as a versatile host for controlled drug delivery and biosensing. The sol-gel template synthesized SNTs have a slow rate of drug release. Application of an external stimulus in the form of ultrasound to or chemical functionalization of synthesized SNT results in higher yield of drug release as well as yield of drug release varying linearly with time. In case of controlled drug delivery triggered by ultrasound, drug yield as function of time is found to be heavily dependent on the ultrasound impulse protocol. Impulses of shorter duration (similar to 0.5 min) and shorter time intervals between successive impulses resulted in higher drug yields. Confinement of hemoglobin (Hb) inside nanometer sized channels of SNT does not have any detrimental effect on the native protein structure and function. Observance of significant enhancement in direct electron transfer of Hb makes the SNTs also promising for application in biosensors.

Many disciplines-common approach: Experiences in the development and delivery of an interprofessional health subject

In 2004, the Faculty of Health Sciences at La Trobe University in Victoria, Australia, introduced a new, final-year subject ‘Interdisciplinary Professional Practice’. The subject is taught to all students enrolled in the 11 allied health and human service disciplines at La Trobe University across metropolitan and rural campuses. The delivery is online to overcome timetabling barriers and to provide time and geographic flexibility. The subject is presented using an enquiry-based learning model. Students are exposed to the concepts of interdisciplinary teamwork through shared learning across professional boundaries to enable a collaborative workforce. An outline of the background development and design of this subject, and its implementation and content areas is presented. A discussion of relevant literature and an analysis of the subject evaluations and focus groups that have guided subject development to enhance student learning over eight cohorts is included.

Reversible polyelectrolyte capsules as carriers for protein delivery

A reversible drug delivery system based on spontaneous deposition of a model protein into preformed microcapsules has been demonstrated for protein delivery applications. Layer-by-Layer assembly of poly(allylamine hydrochloride) (PAH) and poly(methacrylic acid) (PMA) onto polystyrene sulfonate (PSS) doped CaCO3 particles, followed by core removal yielded intact hollow microcapsules having a unique property to induce spontaneous deposition of bovine serum albumin (BSA) at pH below its isoelectric point of 4.8, where it was positively charged. These capsules showed reversible pH dependent open and closed states to fluorescence labeled dextran (FITC-Dextran) and BSA (FITC-BSA). The loading capacity of BSA increased from 9.1 x 10(7) to 2.03 x 10(8) molecules per capsule with decrease in pH from 4.5 to 3.The loading of BSA-FITC was observed by confocal laser scanning microscopy (CLSM), which showed homogeneous distribution of protein inside the capsule. Efficient loading of BSA was further confirmed by atomic force microscopy (AFM) and scanning electron microscopy (SEM).The interior capsule concentration was as high as 209 times the feeding concentration when the feeding concentration was increased from 1 to 10 mg/ml. The deposition was initially controlled by spontaneous loading mechanism at lower BSA concentration followed by diffusion controlled loading at higher concentration; which decreased the loading efficiency from 35% to 7%. Circular dichroism (CD) measurements and Fourier transform infrared spectroscopy (FTIR) confirmed that there was no significant change in conformation of released BSA in comparison with native BSA. The release was initially burst in the first 0.5 h and sustained up to 5 h. The hollow capsules were found to be biocompatible with mouse embryonic fibroblast (MEF) cells during in vitro cell culture studies. Thus these pH sensitive polyelectrolyte microcapsules may offer a promising delivery system for water soluble proteins and peptides. (C) 2010 Elsevier B.V. All rights reserved.

Glucose-Triggered Drug Delivery from Borate Mediated Layer-by-Layer Self-Assembly

In this study, we report a novel approach for glucose-triggered anticancer drug delivery from the self-assembly of neutral poly(vinyln alcohol) (PVA) and chitosan. In the present study, we have fabricated multilayer thin film of PVA-borate and chitosan on colloidal particle (MF particle) and monitored the layer-by-layer growth using Zetapotential measurements. Formation of multilayer membrane on MF particle has been further characterized with transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). Subsequently,disintegration of multilayer thin film and microcapsules was observed in presence of glucose. We investigated the disassembly of PVA-borate and chitosan self-assembly under CLSM and atomic force microscopy. These results suggest that this multilayer thin film is very efficient for encapsulation and release of DOX molecules above certain concentration of glucose (25 mM). This glucose-sensitive self-assembly is relevant for the application of anticancer therapeutic drug delivery.

Dual-Drug Delivery System Based on In Situ Gel-Forming Nanosuspension of Forskolin to Enhance Antiglaucoma Efficacy

The present study was designed to improve the bioavailability of forskolin by the influence of precorneal residence time and dissolution characteristics. Nanosizing is an advanced approach to overcome the issue of poor aqueous solubility of active pharmaceutical ingredients. Forskolin nanocrystals have been successfully manufactured and stabilized by poloxamer 407. These nanocrystals have been characterized in terms of particle size by scanning electron microscopy and dynamic light scattering. By formulating Noveon AA-1 polycarbophil/poloxamer 407 platforms, at specific concentrations, it was possible to obtain a pH and thermoreversible gel with a pH(gel)/T-gel close to eye pH/temperature. The addition of forskolin nanocrystals did not alter the gelation properties of Noveon AA-1 polycarbophil/poloxamer 407 and nanocrystal properties of forskolin. The formulation was stable over a period of 6 months at room temperature. In vitro release experiments indicated that the optimized platform was able to prolong and control forskolin release for more than 5 h. The in vivo studies on dexamethasone-induced glaucomatous rabbits indicated that the intraocular pressure lowering efficacy for nanosuspension/hydrogel systems was 31% and lasted for 12 h, which is significantly better than the effect of traditional eye suspension (18%, 4-6 h). Hence, our investigations successfully prove that the pH and thermoreversible polymeric in situ gel-forming nanosuspension with ability of controlled drug release exhibits a greater potential for glaucoma therapy.

A metabolomic approach to studying mechanisms of polymeric gene delivery to retinal pigment epithelial cells

Tiivistelmä ReferatAbstract Metabolomics is a rapidly growing research field that studies the response of biological systems to environmental factors, disease states and genetic modifications. It aims at measuring the complete set of endogenous metabolites, i.e. the metabolome, in a biological sample such as plasma or cells. Because metabolites are the intermediates and end products of biochemical reactions, metabolite compositions and metabolite levels in biological samples can provide a wealth of information on on-going processes in a living system. Due to the complexity of the metabolome, metabolomic analysis poses a challenge to analytical chemistry. Adequate sample preparation is critical to accurate and reproducible analysis, and the analytical techniques must have high resolution and sensitivity to allow detection of as many metabolites as possible. Furthermore, as the information contained in the metabolome is immense, the data set collected from metabolomic studies is very large. In order to extract the relevant information from such large data sets, efficient data processing and multivariate data analysis methods are needed. In the research presented in this thesis, metabolomics was used to study mechanisms of polymeric gene delivery to retinal pigment epithelial (RPE) cells. The aim of the study was to detect differences in metabolomic fingerprints between transfected cells and non-transfected controls, and thereafter to identify metabolites responsible for the discrimination. The plasmid pCMV-β was introduced into RPE cells using the vector polyethyleneimine (PEI). The samples were analyzed using high performance liquid chromatography (HPLC) and ultra performance liquid chromatography (UPLC) coupled to a triple quadrupole (QqQ) mass spectrometer (MS). The software MZmine was used for raw data processing and principal component analysis (PCA) was used in statistical data analysis. The results revealed differences in metabolomic fingerprints between transfected cells and non-transfected controls. However, reliable fingerprinting data could not be obtained because of low analysis repeatability. Therefore, no attempts were made to identify metabolites responsible for discrimination between sample groups. Repeatability and accuracy of analyses can be influenced by protocol optimization. However, in this study, optimization of analytical methods was hindered by the very small number of samples available for analysis. In conclusion, this study demonstrates that obtaining reliable fingerprinting data is technically demanding, and the protocols need to be thoroughly optimized in order to approach the goals of gaining information on mechanisms of gene delivery.

Poly propyl ether imine (PETIM) dendrimer: A novel non-toxic dendrimer for sustained drug delivery

In the present study, an attempt was made to study the acute and sub-acute toxicity profile of G3-COOH Poly (propyl ether imine) PETIM] dendrimer and its use as a carrier for sustained delivery of model drug ketoprofen. Drug-dendrimer complex was prepared and characterized by FTIR, solubility and in vitro drug release study. PETIM dendrimer was found to have significantly less toxicity in A541 cells compared to Poly amido amine (PAMAM) dendrimer. Further, acute and 28 days sub-acute toxicity measurement in mice showed no mortality, hematological, biochemical or histopathological changes up to 80 mg/kg dose of PETIM dendrimer. The results of study demonstrated that G3-COOH PETIM dendrimer can be used as a safe and efficient vehicle for sustained drug delivery. (C) 2010 Elsevier Masson SAS. All rights reserved.

Polyelectrolyte microcapsules for sustained delivery of water-soluble drugs

Polyelectrolyte capsules composed of weak polyelectrolytes are introduced as a simple and efficient system for spontaneous encapsulation of low molecular weight water-soluble drugs. Polyelectrolyte capsules were prepared by layer-by-layer (LbL) assembling of weak polyelectrolytes, poly(allylamine hydrochloride) (PAH) and poly (methacrylic acid) (PMA) on polystyrene sulfonate (PSS) doped CaCO3 particles followed by core removal with ethylene-diaminetetraacetic add (EDTA). The loading process was observed by confocal laser scanning microscopy (CLSM) using tetramethylrhodamineisothiocyanate labeled dextran (TRITC-dextran) as a fluorescent probe. The intensity of fluorescent probe inside the capsule decreased with increase in cross-linking time. Ciprofloxacin hydrochloride (a model water-soluble drug) was spontaneously deposited into PAH/PMA capsules and their morphological changes were investigated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The quantitative study of drug loading was also elucidated which showed that drug loading increased with initial drug concentration, but decreased with increase in pH. The loaded drug was released in a sustained manner for 6 h, which could be further extended by cross-linking the capsule wall. The released drug showed significant antibacterial activity against E. coli. These findings indicate that such capsules can be potential carriers for water-soluble drugs in sustained/controlled drug delivery applications. (C) 2010 Elsevier B.V. All rights reserved.

Dendritic Poly(ether imine) Based Gene Delivery Vector

The nonviral vector based gene delivery approach is attractive due to advantages associated with molecular-level modifications suitable for optimization of vector properties. In a new class of nonviral gene delivery systems, we herein report the potential of poly(ether Mine) (PETIM) dendrimers to mediate an effective gene delivery function. PETIM dendrimer, constituted with tertiary amine branch points, n-propyl ether linkers and primary amines at their peripheries, exhibits significantly reduced toxicities, over a broad concentration range. The dendrimer complexes pDNA effectively, protects DNA from endosomal damages, and delivers to the cell nucleus. Gene transfection studies, utilizing a reporter plasmid pEGFP-C1 and upon complexation with dendrimer, showed a robust expression of the encoded protein. The study shows that PETIM dendrimers are hitherto unknown novel gene delivery vectors, combining features of poly(ethylene imine)-based polymers and dendrimers, yet are relatively nontoxic and structurally precise.

Needleless Vaccine Delivery Using Micro-Shock Waves

Shock waves are one of the most efficient mechanisms of energy dissipation observed in nature. In this study, utilizing the instantaneous mechanical impulse generated behind a micro-shock wave during a controlled explosion, a novel nonintrusive needleless vaccine delivery system has been developed. It is well-known that antigens in the epidermis are efficiently presented by resident Langerhans cells, eliciting the requisite immune response, making them a good target for vaccine delivery. Unfortunately, needle-free devices for epidermal delivery have inherent problems from the perspective of the safety and comfort of the patient. The penetration depth of less than 100 mu m in the skin can elicit higher immune response without any pain. Here we show the efficient utilization of our needleless device (that uses micro-shock waves) for vaccination. The production of liquid jet was confirmed by high-speed microscopy, and the penetration in acrylamide gel and mouse skin was observed by confocal microscopy. Salmonella enterica serovar Typhimurium vaccine strain pmrG-HM-D (DV-STM-07) was delivered using our device in the murine salmonellosis model, and the effectiveness of the delivery system for vaccination was compared with other routes of vaccination. Vaccination using our device elicits better protection and an IgG response even at a lower vaccine dose (10-fold less) compared to other routes of vaccination. We anticipate that our novel method can be utilized for effective, cheap, and safe vaccination in the near future.

Angelica archengelica extract induced perturbation of rat skin and tight junctional protein (ZO-1) of HaCaT cells

Background and purpose of the study: Herbal enhancers compared to the synthetic ones have shown less toxis effects. Coumarins have been shown at concentrations inhibiting phospoliphase C-Y (Phc-Y) are able to enhance tight junction (TJ) permeability due to hyperpoalation of Zonolous Occludense-1 (ZO-1) proteins. The purpose of this study was to evaluate the influence of ethanolic extract of Angelica archengelica (AA-E) which contain coumarin on permeation of repaglinide across rat epidermis and on the tight junction plaque protein ZO-1 in HaCaT cells. Methods: Transepidermal water loss (TEWL) from the rat skin treated with different concentrations of AA-E was assessed by Tewameter. Scanning and Transmission Electron Microscopy (TEM) on were performed on AA-E treated rat skin portions. The possibility of AA-E influence on the architecture of tight junctions by adverse effect on the cytoplasmic ZO-1 in HaCaT cells was investigated. Finally, the systemic delivery of repaglinide from the optimized transdermal formulation was investigated in rats. Results: The permeation of repaglinide across excised rat epidermis was 7-fold higher in the presence of AA-E (5% w/v) as compared to propylene glycol:ethanol (7:3) mixture. The extract was found to perturb the lipid microconstituents in both excised and viable rat skin, although, the effect was less intense in the later. The enhanced permeation of repaglinide across rat epidermis excised after treatment with AA-E (5% w/v) for different periods was in concordance with the high TEWL values of similarly treated viable rat skin. Further, the observed increase in intercellular space, disordering of lipid structure and corneocyte detachment indicated considerable effect on the ultrastructure of rat epidermis. Treatment of HaCaT cell line with AA-E (0.16% w/v) for 6 hrs influenced ZO-1 as evidenced by reduced immunofluorescence of anti-TJP1 (ZO-1) antibody in Confocal Laser Scanning Microscopy studies (CLSM) studies. The plasma concentration of repaglinide from transdermal formulation was maintained higher and for longer time as compared to oral administration of repaglinide. Major conclusion: Results suggest the overwhelming influence of Angelica archengelica in enhancing the percutaneous permeation of repaglinide to be mediated through perturbation of skin lipids and tight junction protein (ZO-1).

Advantage of the ether linkage between the positive charge and the cholesteryl skeleton in cholesterol-based amphiphiles as vectors for gene delivery

Twelve novel cationic cholesterol derivatives with different linkage types between the cationic headgroup and the cholesteryl backbone have been developed. These have been tested for their efficacies as gene transfer agents as mixtures with dioleoyl phosphatidylethanolamine (DOPE). A pronounced improvement in transfection efficiency was observed when the cationic center was linked to the steroid backbone using an ether type bond. Among these, cholest-5-en-3b-oxyethane-N, N,N-trimethylammonium bromide (2a) and cholest-5-en-3b-oxyethane-N, N-dimethyl-N-2-hydroxyethylammonium bromide (3d) showed transfection efficiencies considerably greater than commercially available reagents such as Lipofectin or Lipofectamine. To achieve transfection, 3d did not require DOPE. Increasing hydration at the headgroup level for both ester- and ether-linked amphiphiles resulted in progressive loss of transfection efficiency. Transfection efficiency was also greatly reduced when a 'disorder'-inducing chain like an oleyl (cis-9-octadecenyl) segment was added to these cholesteryl amphiphiles. Importantly, the transfection ability of 2a with DOPE in the presence of serum was significantly greater than for a commercially available reagent, Lipofectamine. This suggests that these novel cholesterol-based amphiphiles might prove promising in applications involving liposome-mediated gene transfection. This investigation demonstrates the importance of structural features at the molecular level for the design of cholesterol-based gene delivery reagents that would aid the development of newer, more efficient formulations based on this class of molecules.

Pickup and delivery problem using metaheuristics techniques

Dial-a-ride problem (DARP) is an optimization problem which deals with the minimization of the cost of the provided service where the customers are provided a door-to-door service based on their requests. This optimization model presented in earlier studies, is considered in this study. Due to the non-linear nature of the objective function the traditional optimization methods are plagued with the problem of converging to a local minima. To overcome this pitfall we use metaheuristics namely Simulated Annealing (SA), Particle Swarm Optimization (PSO), Genetic Algorithm (GA) and Artificial Immune System (AIS). From the results obtained, we conclude that Artificial Immune System method effectively tackles this optimization problem by providing us with optimal solutions. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.

Biologically triggered exploding protein based microcapsules for drug delivery

Biologically triggered exploding microcapsules were synthesized by layer-by-layer assembly of biopolymers. The microcapsules showed controlled rupturing behaviour upon exposure to a pathologically relevant biomolecule, trypsin. These microcapsules offer significant potential for clinical applications.