Investigation of Electrical Stimuli for Controlled Drug Release from Chitosan DDS

Controlled drug release is crucial for targeted implantable smart drug delivery system (DDS). In this work, simulations and experiments are conducted to demonstrate drug release mechanism using electrical stimulus. For dyed chitosan beads (diameter 500 um to 900 um), a surface acoustic resonator (SAW) chip cavity which has interdigited electrode on quartz surface was used to provide electrical stimulus. Printed circuit board (PCB) and sputter coated interdigited electrodes were used to provide electrical stimulus on the chitosan film. Two simulation models (SAW resonator and chitosan lm) are developed to explain the physical phenomena of drug release using finite element method (FEM). It is found that drug delivery is nonlinearly increased with applied electric field to the electrodes. The AC electro-kinetic (ACEK) force generated from electrical excitation is a factor influencing this phenomenon. Temperature rise was not significant as demonstrated in both simulations and experiments. Different control and stimulus experiments were performed to show the conceptsof dye release from micro beads using electrical stimuli. Dye release has been identified visually for these experiments. Chitosan films loaded with green food coloring were also fabricated to demonstrate the drug release. Experiments were conducted with different electric fields and frequencies on chitosan film. The spectral absorbance of treated solution after the experiment is measured using a spectrophotometer to quantify the dye release. Verification of the dye release with increased applied voltage was statistically proven with 99% level of significance. This study has shown that application of electric field can be a potential candidate for controlled DDS using both chitosan micro-beads/films

Functional Nanomaterials and Polymer Nanocomposites: Current Uses and Potential Applications

This book covers a broad range of subjects, from smart nanoparticles and polymer nanocomposite synthesis and the study of their fundamental properties to the fabrication and characterization of devices and emerging technologies with smart nanoparticles and polymer integration

Ionic liquids for the preparation of biopolymer materials for drug/gene delivery : a review

Biopolymers are particularly suitable for drug applications due to their biocompatibility, biodegradability and low immunogenicity. There has been growing interest in using biopolymers to achieve the controlled release of therapeutics. However, the solubility and processability of biopolymers remain to be challenging due to their structural heterogeneity and dense networks of inter- and intramolecular interactions. Fortunately, ionic liquids (ILs), regarded as green solvents, have been increasingly appreciated for their unparalleled power for biopolymer processing. By dissolution of biopolymers in ILs, various materials including sponges, films, microparticles (MPs), nanoparticles (NPs), and aerogels can be generated as potential drug delivery carriers. Besides, ILs can be used as reaction mediums and/or catalysts for biopolymer chemical reactions, which shows enhanced reaction efficiency. In addition, because of their unique physicochemical (e.g., polarity, hydrophobicity, amphipathicity) and biological properties (e.g., antibacterial activity), ILs can assist or participate in the formation of drug delivery carriers. To cover all these aspects of research, this review provides an overview of the recent progress in using ILs for the engineering of next-generation drug/gene delivery carrier materials. The tunable properties of ILs as affected by their structure are highlighted. Also, the key principles, challenges and prospects in this area are presented

Fully Integrated Biochip Platforms for Advanced Healthcare

Recent advances in microelectronics and biosensors are enabling developments of innovative biochips for advanced healthcare by providing fully integrated platforms for continuous monitoring of a large set of human disease biomarkers. Continuous monitoring of several human metabolites can be addressed by using fully integrated and minimally invasive devices located in the sub-cutis, typically in the peritoneal region. This extends the techniques of continuous monitoring of glucose currently being pursued with diabetic patients. However, several issues have to be considered in order to succeed in developing fully integrated and minimally invasive implantable devices. These innovative devices require a high-degree of integration, minimal invasive surgery, long-term biocompatibility, security and privacy in data transmission, high reliability, high reproducibility, high specificity, low detection limit and high sensitivity. Recent advances in the field have already proposed possible solutions for several of these issues. The aim of the present paper is to present a broad spectrum of recent results and to propose future directions of development in order to obtain fully implantable systems for the continuous monitoring of the human metabolism in advanced healthcare applications

Intelligente Drug-Delivery-Systeme zur Vermeidung Implantat-assoziierter Infektionen

All medical devices and implants are made of synthetic or natural, but usually not endogenous, materials. Implantation of such devices, into living tissue, is therefore subject to the risk of nosocomial infections, biofilm formation and may cause implant-associated infections. Microorganisms (including bacteria) that grow in biofilms and cause chronic inflammation are the typical source of these infections. Subsequently, they can lead to implant failure, requiring further surgical treatments. To prevent this, this study investigated and presented enzymatically degradable drug delivery systems that enable encapsulation and targeted release of an antibacterial agent triggered by an infection. To achieve this, the dissertation focused on the fabrication, characterization of suitable nanocarriers and their immobilization on implant surfaces such as titanium. To build a stable and degradable encapsulation system, different steps were established: 1) the integration of an enzyme-labile model peptide into two different polymer-based systems 2) generation of particles 3) coating of titanium surfaces with the particles 4) investigation of stability and degradability of those systems 5) the release of ciprofloxacin as a model substance. For this, two approaches have been tested. The first approach included the synthesis of chitosan‐g‐[peptide‐poly‐L‐caprolactone] and its self‐assembly into polymeric vesicles by the solvent shift method. For the second approach, nanogels dispersions were prepared by ionotropic gelation of the alginate with the poly-L-lysine, which was conjugated with ciprofloxacin via a copper-free 1,3-dipolar cycloaddition (click reaction).Alle medizinischen Geräte und Implantate bestehen aus synthetischen oder natürlichen, jedoch in der Regel aus nicht endogenen Materialien. Die Implantation solcher Geräte in lebendes Gewebe unterliegt daher dem Risiko nosokomialer Infektionen und der Bildung von Biofilmen und kann implantatassoziierte Infektionen verursachen. Mikroorganismen (einschließlich Bakterien), die in Biofilmen wachsen und chronische Entzündungen verursachen, sind die typische Quelle dieser Infektionen. Anschließend können sie zu einem Implantatversagen führen, was weitere chirurgische Behandlungen erforderlich macht. Um dies zu verhindern, untersuchte und ergab diese Studie enzymatisch abbaubare Arzneimittelabgabesysteme, die die Einkapselung und gezielte Freisetzung eines durch eine Infektion ausgelösten antibakteriellen Mittels ermöglichen. Um dies zu erreichen, konzentrierte sich die Dissertation auf die Herstellung und Charakterisierung geeigneter Nanoträger sowie deren Immobilisierung auf Implantatoberflächen wie Titan. Um ein stabiles und abbaubares Einkapselungssystem aufzubauen, wurden verschiedene Schritte festgelegt: 1) Integration eines enzymlabilen Modellpeptids in zwei verschiedene Systeme auf Polymerbasis 2) Erzeugung von Partikeln 3) Beschichtung von Titanoberflächen mit den Partikeln 4) Untersuchung von Stabilität und Abbaubarkeit dieser Systeme 5) Freisetzung von Ciprofloxacin als Modellsubstanz. Hierzu wurden zwei Ansätze getestet. Der erste Ansatz umfasste die Synthese von Chitosan-g-[Peptid-Poly-ε-Caprolacton] und dessen Selbstorganisation zu polymeren Vesikeln durch das Lösungsmittel-Verschiebungsverfahren. Für den zweiten Ansatz wurden Nanogeldispersionen durch ionotrope Gelierung des Alginats mit dem Poly-L-Lysin hergestellt, das über eine kupferfreie 1,3-dipolare Cycloaddition (Klickreaktion) mit Ciprofloxacin konjugiert wurde

Polyelectrolyte gels: fundamentals, fabrication and applications

Polyelectrolyte gels are an important class of polymer gels and a versatile platform with charged polymer networks with ionisable groups. They have drawn significant recent attention as a class of smart material and have demonstrated potential for a variety of applications. This review begins with the fundamentals of polyelectrolyte gels, which encompass various classifications (i.e., origin, charge, shape) and crucial aspects (ionic conductivity and stimuli responsiveness). It further centralises recent developments of polyelectrolyte gels, emphasising their synthesis, structure–property relationships and responsive properties. Sequentially, this review demonstrates how polyelectrolyte gels’ flourishing properties create attractiveness to a range of applications including tissue engineering, drug delivery, actuators and bioelectronics. Finally, the review outlines the indisputable appeal, further improvements and emerging trends in polyelectrolyte gelsNisal Wanasingha, Pramod Dorishetty, Naba K. Dutta and Namita Roy Choudhur