Andres Garcia

Polymeric and biomacromolecular brush nanostructures: progress in synthesis, patterning and characterization

A significant scientific and engineering challenge of recent years has been the fabrication of patterned polymeric and biomacromolecular brush nanostructures on surfaces. These structures provide researchers with a rich platform on which to exploit and observe nanoscale phenomena. In this review we present an overview of the field and highlight, through selected examples, recent advances in the nanostructuring of polymer and biomacromolecular brushes. This includes a brief overview of polymer brush synthesis techniques and how these are integrated with nanolithographic and templating approaches. We discuss the characterization of polymeric nanostructures and its associated difficulties, and we provide some perspective of how we see the future direction of the field evolving.

Versatile synthesis and micropatterning of nonfouling polymer brushes on the wafer scale

In this article, the authors describe new approaches to synthesize and pattern surfaces with poly[oligo(ethylene glycol) methyl methacrylate] (POEGMA) polymer brushes synthesized by surface-initiated atom transfer radical polymerization. These patterned coatings confer “nonfouling” properties protein and cell resistance—to the surface in a biological milieu. The versatile routes for the synthesis of POEGMA demonstrated here offer clear advantages over other techniques previously used in terms of their simplicity, reliability, and ability to pattern large-area substrates. They also demonstrate that POEGMA polymer brushes can be patterned directly by photolithography, plasma ashing, and reactive ion etching to create patterns at the micro- and nanoscale over large areas with high throughput and repeatability, while preserving the protein and cell resistance of the POEGMA brush.

Microfabricated Engineered Particle Systems for Respiratory Drug Delivery and Other Pharmaceutical Applications

Particle Replication in Non-Wetting Templates (PRINT®) is a platform particle drug delivery technology that coopts the precision and nanoscale spatial resolution inherently afforded by lithographic techniques derived from the microelectronics industry to produce precisely engineered particles. We describe the utility of PRINT technology as a strategy for formulation and delivery of small molecule and biologic therapeutics, highlighting previous studies where particle size, shape, and chemistry have been used to enhance systemic particle distribution properties. In addition, we introduce the application of PRINT technology towards respiratory drug delivery, a particular interest due to the pharmaceutical need for increased control over dry powder characteristics to improve drug delivery and therapeutic indices. To this end, we have produced dry powder particles with micro- and nanoscale geometric features and composed of small molecule and protein therapeutics. Aerosols generated from these particles show attractive properties for efficient pulmonary delivery and differential respiratory deposition characteristics based on particle geometry. This work highlights the advantages of adopting proven microfabrication techniques in achieving unprecedented control over particle geometric design for drug delivery.