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We report a facile interfacial engineering method that can drastically modulate the photoelectrochemical properties of two-dimensional transition metal dichalcogenide (TMD) semiconductors. We find that the adsorption of Zn-centred protoporphyrins strongly influences the photocurrent, depending on the relative energy levels of the TMDs against those of the chromophore molecules. [ABSTRACT FROM AUTHOR]

The unique physical properties of single-walled carbon nanotubes (SWCNTs) have been exploited in novel applications in various fields including electronics and life sciences. Their photoluminescence in the near-infrared (NIR) range, where optical interference from biological tissues is minimum, has rendered them particularly attractive as optical probes in biological environments. Herein we review the use of the SWCNT NIR emission in bio-sensing and imaging. To interface the insoluble carbon nanotubes with an aqueous biological environment, biomaterials and organic polymers have been widely used for non-covalently functionalizing SWCNTs. Such functionalization minimizes the toxicity of carbon nanotubes in biological and physiological environments, while maintaining their optical properties. SWCNTs have been demonstrated as both in vitro and in vivo optical sensors, targeting biologically important molecules, such as neurotransmitters and cell signaling molecules. For optical imaging, functionalized SWCNTs were used as NIR contrast agents for probing cellular processes and imaging plants and small animals. We also discuss emerging SWCNT-based super-resolution schemes. We conclude that SWCNTs are promising optical materials for basic life science research, biomedical diagnostics, and therapeutics. [ABSTRACT FROM AUTHOR]

The goal of this work has been to synthesize and investigate Pd(TC3), an intercalating porphyrin that has conformable substituents capable of groove binding to B-form DNA. (TC3 denotes the doubly deprotonated form of 5,10,15,20-tetra[3-(3′-methylimidazolium-1′-yl)prop-1-yl]porphyrin.) Palladium(ii) is an apt choice for the central metal ion because it remains strictly four-coordinate and provides for a luminescent triplet excited state with a long lifetime. The DNA hosts are hairpin-forming sequences programmed to differ in base composition. Luminescence, absorbance, and circular dichroism results are consistent with the idea that congruent structural reorganization takes place at the host and ligand during uptake. Photoexcitation of DNA-bound Pd(TC3) generates a comparatively modest steady state concentration of singlet oxygen, due to a relatively slow reaction with molecular oxygen in solution. The sheer size of the substituent groups disfavors quenching, but groove-binding interactions compound the problem by inhibiting mobility. The results show how ligand design affects adduct structure as well as function. [ABSTRACT FROM AUTHOR]

Here we design a DNA origami-based site-specific molecular capture and release platform operated by a DNAzyme-mediated logic gate process. We show the programmability and versatility of this platform with small molecules, proteins, and nanoparticles, which may also be controlled by external light signals. [ABSTRACT FROM AUTHOR]

The goal of this work has been to synthesize and investigate Pd(TC3), an intercalating porphyrin that has conformable substituents capable of groove binding to B-form DNA. (TC3 denotes the doubly deprotonated form of 5,10,15,20-tetra[3-(3'-methylimidazolium-1'-yl)prop-1-yl]porphyrin.) Palladium(ii) is an apt choice for the central metal ion because it remains strictly four-coordinate and provides for a luminescent triplet excited state with a long lifetime. The DNA hosts are hairpin-forming sequences programmed to differ in base composition. Luminescence, absorbance, and circular dichroism results are consistent with the idea that congruent structural reorganization takes place at the host and ligand during uptake. Photoexcitation of DNA-bound Pd(TC3) generates a comparatively modest steady state concentration of singlet oxygen, due to a relatively slow reaction with molecular oxygen in solution. The sheer size of the substituent groups disfavors quenching, but groove-binding interactions compound the problem by inhibiting mobility. The results show how ligand design affects adduct structure as well as function.