Site-selective surface enhanced Raman scattering study of ligand exchange reactions on aggregated Ag nanocubes.

Surface modification of ligand protected nanoparticles (NPs) can be driven by ligand exchange reactions (LER). Little is known about the mechanism of this reaction, especially when the particles are not spherical. Here, we use the intrinsic hot spots generated on the corners/edges of 40 nm silver nanocubes (AgNCs) and the extrinsic hot spots generated by the aggregation of AgNCs to obtain strong enhancements in surface enhanced Raman scattering (SERS) to monitor the displacement of poly(vinylpyrrolidone) with either a hydrophilic (sodium 11-mercapto-1-undecanesulfonate, MUS) or a hydrophobic ligand (1-octanethiol, OT).

Single-molecule DNA sequencing of widely varying GC-content using nucleotide release, capture and detection in microdroplets.

Despite remarkable progress in DNA sequencing technologies there remains a trade-off between short-read platforms, having limited ability to sequence homopolymers, repeated motifs or long-range structural variation, and long-read platforms, which tend to have lower accuracy and/or throughput. Moreover, current methods do not allow direct readout of epigenetic modifications from a single read. With the aim of addressing these limitations, we have developed an optical electrowetting sequencing platform that uses step-wise nucleotide triphosphate (dNTP) release, capture and detection in microdroplets from single DNA molecules.

Bimodal atomic force microscopy for the characterization of thiolated self-assembled monolayers.

Surface coatings are becoming an integral part of materials. In recent years, molecular coatings have found larger acceptance and uses. Among them, self-assembled monolayers (SAMs) are attractive due to their inherent versatility, manufacturability, and scale up ease.

Cyclodextrin Modulated Type I Collagen Self-Assembly to Engineer Biomimetic Cornea Implants.

Collagen-rich tissues in the cornea exhibit unique and highly organized extracellular matrix ultrastructures, which contribute to its high load-bearing capacity and light transmittance. Corneal collagen fibrils are controlled during development by small leucine-rich proteoglycans (SLRPs) that regulate the fibril diameter and spacing in order to achieve the unique optical transparency. Cyclodextrins (CDs) of varying size and chemical functionality for their ability to regulate collagen assembly during vitrification process are screened in order to create biosynthetic materials that mimic the native cornea structure.

Morphology Engineering: A Route to Highly Reproducible and High Efficiency Perovskite Solar Cells.

Despite the rapid increase in the performance of perovskite solar cells (PSC), they still suffer from low lab-to-lab or people-to-people reproducibility. Aiming for a universal condition to high-performance devices, we investigated the morphology evolution of a composite perovskite by tuning annealing temperature and precursor concentration of the perovskite film. Here, we introduce thermal annealing as a powerful tool to generate a well-controlled excess of PbI in the perovskite formulation and show that this benefits the photovoltaic performance.