A monolithic polymeric microdevice for pH-responsive drug delivery

Abstract

A drug-delivery microdevice integrating pH-responsive nano-hydrogel particles functioning as intelligent nano valves is described. The polymeric microdevices are monolithic without requiring peripheral control hardware or additional components for controlling drug-release rates. pH-responsive nanoparticles were synthesized and embedded into a composite membrane. The resulting pH-responsive composite membranes were integrated with PDMS micro reservoirs via a room-temperature transfer bonding technique to form the proof-of-concept microdevices. In vitro release characterization of the microdevices was conducted in which the release rate of Vitamin B(12) (VB(12)) as a model drug increased dramatically when the local pH value was decreased from 7.4 to 4. This device concept can serve as a platform technology for intelligent drug delivery in response to various in vivo environmental signals.

Analytical solution for transient electroosmotic flow in a rotating microchannel

“…[1][2][3][4][5][6] The thickness of the EDL is comparable with the size of the microchannel so the length scales of the electrostatic interactions enable the development of many highimpact technologies in the area of electrokinetic transport in microchannels. In such technologies, electroosmotic ow (EOF) is the prevalent phenomenon for the transport of small volumes of aqueous solutions when an electric eld is applied across a microchannel with charged walls.…”

pH‐Responsive Drug‐Delivery Systems

“…Oral administration of insulin-loaded hydrogels to streptozotocin-induced diabetic rats led to a continuous decline in the fasting blood glucose level within 6 h post-administration, and the relative pharmacological availability increased more than 10 times compared with oral administration of a solution of free insulin. Chen et al [14] reported a drug-delivery microdevice that integrated pH-responsive hydrogel nanoparticles that acted as intelligent valves; they prepared pH-responsive hydrogel nanoparticles that were embedded into a composite membrane and the resulting pH-responsive composite membranes were integrated with polydimethylsiloxane microreservoirs through a room-temperature transfer bonding technique to form the proof-of-concept microdevice. They found that the release rate of vitamin B12 as a model drug increased dramatically when the local pH value was decreased from 7.4 to 4.…”

Approaches and Challenges of Engineering Implantable Microelectromechanical Systems (MEMS) Drug Delivery Systems for in Vitro and in Vivo Applications

“…One area of great interest are flow control systems utilizing responsive hydrogels, as they are biocompatible and can be specifically engineered to respond a variety of factors and marker molecules within the blood such as temperature, pH, saccharide and antigen concentration [57,58]. These factors fluctuate as the disease being treated, and thereby allowing the drug delivery system to evaluate the effectiveness of the drug administered [58][59][60][61].…”