Electroactive controlled release thin films

Abstract

We present the fabrication of nanoscale electroactive thin films that can be engineered to undergo remotely controlled dissolution in the presence of a small applied voltage (؉1.25 V) to release precise quantities of chemical agents. These films, which are assembled by using a nontoxic, FDA-approved, electroactive material known as Prussian Blue, are stable enough to release a fraction of their contents after the application of a voltage and then to restabilize upon its removal. As a result, it is possible to externally trigger agent release, exert control over the relative quantity of agents released from a film, and release multiple doses from one or more films in a single solution. These electroactive systems may be rapidly and conformally coated onto a wide range of substrates without regard to size, shape, or chemical composition, and as such they may find use in a host of new applications in drug delivery as well as the related fields of tissue engineering, medical diagnostics, and chemical detection.drug delivery ͉ layer-by-layer thin film ͉ polymer ͉ responsive materials ͉ Prussian Blue

Programmable and on-demand drug release using electrical stimulation

“…Among them, pulsatile drug delivery systems (PDDS) have drawn attention as they allow repeatable and reliable drug release flux for clinical needs. Further, external stimulation signals such as temperature variation, 9,10 magnetic fields, [11][12][13][14] and electric fields, [15][16][17][18][19][20][21] can be used in PDDS to trigger or control drug release rates, thereby allowing remote control of local drug administration. Most of the PDDS devices are composed of a drug-loading container covered with a functional membrane, with drug release rates through the functional membrane controlled by modulating the external stimulations.…”

Temperature Induced Solubility Transitions of Various Poly(2-oxazoline)s in Ethanol-Water Solvent Mixtures

“…A wide range of response factors, i.e., triggers, have been developed such as chemical or biological agents for sensors [9][10][11], mechanical forces [12,13], UV-vis or near-IR irradiation [14,15], magnetic and electrical fields [16,17] as well as temperature [18]. The response of the "smart" material to the external triggering event can be manifold too, ranging from surface energy switching [10,19], a shape change [20], variation in absorption or emission [12], or the material can undergo a phase transition [15,18].…”

Active scaffolds for on-demand drug and cell delivery

“…In all these cases, it is highly desirable to trigger and/or regulate the delivery of biological agents (e.g., drugs and cells) with external cues, because dynamical control over delivery can potentially improve the safety and efficiency of the agents, and permit new therapies (18). In the field of drug delivery, active biomaterials that are responsive to external stimuli such as temperature, pH, enzymes, and various physical fields have been extensively explored for controlled delivery (19)(20)(21)(22)(23)(24). On the other hand, the porous scaffolds currently used in tissue engineering and cell therapy are mostly passive in that they deliver biological agents mainly through mechanisms involving molecular diffusion, material degradation, and cell migration, which do not allow for dynamic external regulations.…”