Photoexcitations in linear trans-quinacridone

Hydrogen Bonding Nanoarchitectonics of Organic Pigment-Based Janus Microrobots with Entering Capability into Cancer Cells

Autonomous microrobots are at the forefront of biomedical research as they are expected to be applied for specific tasks at the intracellular level such as cargo delivery, sensing, molecular manipulation, among others. Here, we report on a preparation of microrobots based on quinacridone and indigo, which are members of the organic hydrogen-bonded pigment family. The microrobots were fabricated by asymmetric platinum deposition on corresponding quinacridone and indigo microparticles that possessed a homogeneous size and shape distribution. The microrobots exhibited autonomous locomotion in the presence of hydrogen peroxide, which was further supported by UV irradiation. The organic pigment-based microrobots were studied in the presence of mouse colorectal carcinoma cells, and it was observed that they were internalized into the cells. Internalization was visualized using confocal laser scanning microscopy. This study reveals the possibility of fabricating hydrogen-bonded organic pigment-based microrobots for biomedical applications by employing the principles of nanoarchitectonics.

Hydrogen-bonds in molecular solids - from biological systems to organic electronics

Hydrogen-bonding (H-bonding) is a relatively strong, highly directional, and specific noncovalent interaction present in many organic molecules, and notably is responsible for supramolecular ordering in biological systems. The H-bonding interactions play a role in many organic electrically conducting materials - in particular in those related to biology, e.g. melanin and indigo. This article aims to highlight recent work on application of nature-inspired H-bonded organic molecules in organic electronic devices. Three topics are covered in this brief review: (1) electrical and ionic conduction in natural H-bonded systems, (2) semiconducting properties of H-bonded organic pigments, and (3) exploitation of H-bonding for supramolecular assembly of organic conductors. H-bonding interactions are ubiquitous in biology, thus making the study of H-bonded organic semiconductors highly pertinent where interfacing of electronics with biological systems is desired.