Design of Multiresponsive Hydrogel Particles and Assemblies

Abstract

In the realm of soft nanotechnology, hydrogel micro‐ and nanoparticles represent a versatile class of responsive materials. Over the last decade, our group has investigated the synthesis and physicochemical properties of a variety of synthetic hydrogel particles. From these efforts, several particle types have emerged with potentially enabling features for biological applications, including nanogels for targeted drug delivery, microlenses for biosensing, and coatings for biomedical devices. For example, core/shell nanogels have been used to encapsulate and deliver small interfering RNA to ovarian cancer cells; nanogels used in this fashion may improve therapeutic outcomes for a variety of macromolecular therapeutics. Microgels arranged as multilayers on implantable biomaterials greatly minimize the host inflammatory response to the material. Furthermore, the triggered release of drugs (i.e., insulin) has been demonstrated from similar assemblies. The goal of this feature article is to highlight developments in the design of responsive microgels and nanogels in the context of our recent efforts and in relation to the community that has grown up around this fascinating class of materials.

Isostructural solid–solid phase transition in monolayers of soft core–shell particles at fluid interfaces: structure and mechanics

“…From the applications' side 15 , microgels are frequently studied as drug delivery vehicles, where active molecules can be incorporated in the hydrogel network and leaked out at a controlled rate or released by external triggers 16,17 . They also attract particular interest as stabilizers for inorganic nanoparticles allowing the fabrication of responsive hybrid materials 18 , and have been used as substrates for cell culture 19,20 , for the fabrication of micro-lens arrays 21,22 and interferometers 23 , and for surface patterning [24][25][26][27][28][29] and film formation 30 .…”

Visual optical biosensors based on DNA-functionalized polyacrylamide hydrogels

“…Finally, various optical responses might be introduced into the gel, where the gel is used as a matrix for immobilization. These stimuli responsive gels are highly attractive for various applications including controlled drug release, sensing, switchable cell culture substrates and for flow control [21][22][23][24][25][26].…”

Preparation of Responsive Micrometer‐Sized Microgel Particles with a Highly Functionalized Shell

“…They have attracted vast attention in soft matter research since their size, softness and physical properties can be tuned to external stimuli, such as temperature, pH, or magnetic and electric fi elds. [ 1 ] Perhaps the best-studied responsive microgel particles are composed of the environmentally responsive polymer poly( N -isopropylacrylamide) (PNIPAM), [2][3][4] which shows a lower critical solution temperature (LCST) at around 32 ° C. Below this temperature, the microgel particles are in a highly swollen state in water. However, when the temperature is raised above the volume phase transition temperature (VPTT), the solubility of the polymers decreases dramatically and the microgels collapse, segregating the polymer and expelling water solvent.…”