Self-folding polymeric containers for encapsulation and delivery of drugs

Abstract

Self-folding broadly refers to self-assembly processes wherein thin films or interconnected planar templates curve, roll-up or fold into three dimensional (3D) structures such as cylindrical tubes, spirals, corrugated sheets or polyhedra. The process has been demonstrated with metallic, semiconducting and polymeric films and has been used to curve tubes with diameters as small as 2 nm and fold polyhedra as small as 100 nm, with a surface patterning resolution of 15 nm. Self-folding methods are important for drug delivery applications since they provide a means to realize 3D, biocompatible, all-polymeric containers with well-tailored composition, size, shape, wall thickness, porosity, surface patterns and chemistry. Self-folding is also a highly parallel process, and it is possible to encapsulate or self-load therapeutic cargo during assembly. A variety of therapeutic cargos such as small molecules, peptides, proteins, bacteria, fungi and mammalian cells have been encapsulated in self-folded polymeric containers. In this review, we focus on self-folding of all-polymeric containers. We discuss the mechanistic aspects of self-folding of polymeric containers driven by differential stresses or surface tension forces, the applications of self-folding polymers in drug delivery and we outline future challenges.

Biomimetic Microelectronics for Regenerative Neuronal Cuff Implants

“…Imitating this behavior of nature archetypes, synthetic systems attain adaptability to environmental changes (e.g., artifi cial irises [ 1 ] adjust to the light intensity) as well as possibility to interact with the environment mechanically [ 2,3 ] or chemically. [ 4,5 ] Mimicking the mechanics of the plant cell swelling process in osmosis, the shape of soft objects can be tailored by using stimuli-responsive polymers. [ 6 ] In hydrogel composites, [ 7 ] a reversible shape transformation including elongation, twisting, or folding [ 8 ] is achieved upon external chemical or thermal stimulation rendering these biomimetic devices to be mechanically active.…”

Magnetic Micro-Origami

“…Gagler [21] and Gracias et al [23][24][25][26][27][28][29][30][31] showed that the surface tension of evaporating drop of liquid is sufficient to pull the walls of the photolithographically defined thin film patterns together and form various figures, such as boxes or pyramids with the size of several micrometers. These patterns typically consist of more rigid areas connected by thinner areas, which serve as hinges, when the thicker walls fold.…”

Smart Delivery Systems with Shape Memory and Self-Folding Polymers

“…These mechanisms can be patterned templates or thin films which can be folded, curved, or rolled-up to become spirals, tubes, and cylindrical tubes [73,74]. Selffolding can occur spontaneously or in response to stimuli such as light, pH [75], temperature, magnetic field, or solvent [76,77]. In Figure 6, self-folding mechanism which is provided by hinges is shown briefly.…”