Developing Biotemplated Data Storage: Room Temperature Biomineralization of L1<inf>0</inf> CoPt Magnetic Nanoparticles

L10 cobalt platinum can be used to record data at approximately sixfold higher densities than it is possible to on existing hard disks. Currently, fabricating L10 CoPt requires high temperatures (≈500 °C) and expensive equipment. One ecological alternative is to exploit biomolecules that template nanomaterials at ambient temperatures. Here, it is demonstrated that a dual affinity peptide (DAP) can be used to biotemplate L10 CoPt onto a surface at room temperature from an aqueous solution. One part of the peptide nucleates and controls the growth of CoPt nanoparticles from solution, and the other part binds to SiO2. A native silicon oxide surface is functionalized with a high loading of the DAP using microcontact printing. The DAP biotemplates a monolayer of uniformly sized and shaped nanoparticles when immobilized on the silicon surface. X-ray diffraction shows that the biotemplated nanoparticles have the L10 CoPt crystal structure, and magnetic measurements reveal stable, multiparticle zones of interaction, similar to those seen in perpendicular recording media. This is the first time that the L10 phase of CoPt has been formed without high temperature/vacuum treatment (e.g., annealing or sputtering) and offers a significant advancement toward developing environmentally friendly, biotemplated materials for use in data storage

Self-folded redox/acid dual-responsive nanocarriers for anticancer drug delivery

Self-folded redox/acid dual-responsive nanocarriers (RAD-NCs) are developed for physiologically triggered delivery of anticancer drug. The evidenced redox/acid responsiveness, facile decoration of ligands, and active tumor-targeting capability of RAD-NCs suggest their potential as a promising formulation for tumor-targeted chemotherapy

A dual wavelength-activatable gold nanorod complex for synergistic cancer treatment

A multifunctional gold nanorod complex was formulated for synergistic anticancer treatment upon ultraviolet (UV) and infrared (IR) light dual irradiations

Light-Activated Hypoxia-Responsive Nanocarriers for Enhanced Anticancer Therapy

A light-activated hypoxia-responsive conjugated polymer-based nanocarrier is developed for efficiently producing singlet oxygen ((1) O2 ) and inducing hypoxia to promote release of its cargoes in tumor cells, leading to enhanced antitumor efficacy. This dual-responsive nanocarrier provides an innovative design guideline for enhancing traditional photodynamic therapeutic efficacy integrated with a controlled drug-release modality

Catalytic Applications of Bio-inspired Nanomaterials

The biomimetic synthesis of Pd nanoparticles was presented using the Pd4 peptide, TSNAVHPTLRHL, isolated from combinatorial phage display library. Using this approach, nearly monodisperse and spherical Pd nanoparticles were generated with an average diameter of 1.9 ± 0.4 nm. The peptide-based nanocatalyst were employed in the Stille coupling reaction under energy-efficient and environmentally friendly reaction conditions of aqueous solvent, room temperature and very low catalyst loading. To this end, the Pd nanocatalyst generated high turnover frequency (TOF) value and quantitative yields using ≥ 0.005 mol% Pd as well as catalytic activities with different aryl halides containing electron-withdrawing and electron-donating groups. The Pd4-capped Pd nanoparticles followed the atom-leaching mechanism and were found to be selective with respect to substrate identity. On the other hand, the naturally-occurring R5 peptide (SSKKSGSYSGSKGSKRRIL) was employed in the synthesis of biotemplated Pd nanomaterials which showed morphological changes as a function of Pd:peptide ratio. TOF analysis for hydrogenation of olefinic alcohols showed similar catalytic activity regardless of nanomorphology. Determination of catalytic properties of these bio-inspired nanomaterials are important as they serve as model system for alternative green catalyst with applications in industrially important transformations

Exploring the mechanism of Stille C-C coupling via peptide-capped Pd nanoparticles results in low temperature reagent selectivity

Herein we systematically probed the atom-leaching mechanism of Pd nanoparticle-driven Stille coupling to further elucidate the fate of the highly active Pd 0 atoms released in solution. In this regard, initial oxidative addition at the particle surface results in Pd atom abstraction for reactivity in solution. As a result, two reaction sites are present, the particle surface and pre-leached Pd atoms, thus different degrees of reactivity are possible. This effect was probed via aryl halide combinations that varied the halogen identity allowing for oxidative addition of two substrates simultaneously. The results demonstrate that the system was highly reactive for iodo-based compounds in the mixture at room temperature; however, reactivity at bromo-based substrates was only observed at slightly elevated temperatures of 40.0 °C. As such, substrate selectivity was evident from the catalytic materials that can be controlled based upon the aryl halide composition and reaction temperature. Furthermore, both inter molecular and intra molecular selectivity is possible, thus raising the degree of reaction complexity that can be achieved. Peptide-capped Pd nanoparticles act as low-temperature, selective catalysts based upon the catalytic mechanism, aryl halide composition, and reaction temperature

CHAPTER 7 - Pd Nanoparticles in C–C Coupling Reactions

Transition metal nanoparticles play an exceedingly important role in driving catalytic reactions. The maximization of the surface-to-volume ratio achieved by materials on the nanoscale is critically important toward enhancing reaction rates; however, the ligands bound to the metallic surface to impart particle stabilization can lead to catalytic poisoning. This is especially true for C–C coupling reactions, where current studies have demonstrated remarkable catalytic activity from a variety of Pd nanoparticles. In this chapter, recent advances in the use of ligand-stabilized Pd nanoparticles to drive C–C coupling reactions are reviewed. Particular emphasis is focused on environmentally-friendly and energy efficient coupling reactions using pseudo-homogeneous catalysts, where modern studies have suggested such capabilities could arise for nanocatalytic materials