Colloidal gold and silver triangular nanoprisms

Electrostatic surface modifications to improve gene delivery

IMPORTANCE OF THE FIELD

Gene therapy has the potential to treat a wide variety of diseases, including genetic diseases and cancer.

AREAS COVERED IN THIS REVIEW

This review introduces biomaterials used for gene delivery and then focuses on the use of electrostatic surface modifications to improve gene delivery materials. These modifications have been used to stabilize therapeutics in vivo, add cell-specific targeting ligands, and promote controlled release. Coatings of nanoparticles and microparticles as well as non-particulate surface coatings are covered in this review. Electrostatic principles are crucial for the development of multilayer delivery structures fabricated by the layer-by-layer method.

WHAT THE READER WILL GAIN

The reader will gain knowledge about the composition of biomaterials used for surface modifications and how these coatings and multilayers can be utilized to improve spatial control and efficiency of delivery. Examples are shown for the delivery of nucleic acids, including DNA and siRNA, to in vitro and in vivo systems.

TAKE HOME MESSAGE

The versatile and powerful approach of electrostatic coatings and multilayers will lead to the development of enhanced gene therapies.

Size-controlled growth of colloidal gold nanoplates and their high-purity acquisition

A facile while flexible approach to size-controllable high-purity colloidal gold nanoplates has been presented. By adjusting the quantity of seeds and I(-) through a seed-mediated, cetyltrimethylammonium bromide (CTABr)-assisted synthetic system, the edge length of the gold nanoplates can be adjusted from 140 to 30 nm without changing their thickness or crystal structure. By simply increasing the ion concentration of the reaction solution, the as-prepared gold nanoplates can be deposited due to the different electrostatic aggregation effects between nanoplates and spherical nanoparticles. Effective storage methods to keep the structural and optical stability of these gold nanoplates are also proposed.

Gold colloids with unconventional angled shapes

We report the formation of porous gold nanoparticles with unusual, angled shapes (such as nanocheckmarks) through spontaneous transformation of tellurium sacrificial templates by gradual galvanic replacement. High-resolution electron microscopy studies of intermediate stages reveal interesting information regarding the replacement mechanism, which involves initial "gold island growth" at the edges, and gradual branching to engulf the entire particle templates, resulting in a highly porous structure. Additionally, the high porosity of these novel nanostructures with unusual shapes is demonstrated to provide very high enhancement of the Raman scattering signal from adsorbed molecules.