Quantum Dots for Improved Single-Molecule Localization Microscopy

Abstract

Colloidal semiconductor quantum dots (QDs) have long established their versatility and utility for the visualization of biological interactions. On the single-particle level, QDs have demonstrated superior photophysical properties compared to organic dye molecules or fluorescent proteins, but it remains an open question as to which of these fundamental characteristics are most significant with respect to the performance of QDs for imaging beyond the diffraction limit. Here, we demonstrate significant enhancement in achievable localization precision in QD-labeled neurons compared to neurons labeled with an organic fluorophore. Additionally, we identify key photophysical parameters of QDs responsible for this enhancement and compare these parameters to reported values for commonly used fluorophores for super-resolution imaging.

CdS Quantum Dots as Potent Photoreductants for Organic Chemistry Enabled by Auger Processes

“…Semiconductor quantum dots (QDs) combine advantageous aspects of both homogeneous (high surface–volume ratio, solubility in reaction media, light penetration) and heterogeneous (durability, substrate binding) catalysts, and therefore offer new opportunities for photoredox catalysis. , QDs have proven to be robust fluorophores and photocatalysts, generally exhibiting superior photostability to small-molecule dyes; − however, applications of QDs to organic synthesis remain underexplored. To address the need for continued development of photoredox catalysts, our group and others have been interested in new applications of QDs in organic chemistry. ,− In addition to their high photostability, QDs exhibit tunable, size-dependent optical and redox properties; are made in single-step syntheses with no chromatography from abundant precursors; reversibly bind to many molecules at once (typically 1–5 ligands/nm 2 of QD surface are found for CdSe QDs − ) through common organic functional groups (−CO 2 H, −PO 3 H, −SH, −NH 2 ); can become charged with many electrons at once without decomposing; , and undergo many electronic processes with no direct analogue in small molecules …”

A Quantum Dot Biomimetic for SARS-CoV-2 to Interrogate Dysregulation of the Neurovascular Unit Relevant to Brain Inflammation

“…Synthesis of the QDs occurred on a Schlenk line under N2 with heating and stirring. Briefly, CdSe cores were synthesized from a protocol adapted from those previously reported, where Cd and Se precursors were reacted with various coordinating ligands where after a brief nucleation step at elevated temperature, the nanocrystals were annealed for up to 2 hours to achieve desired core size, as determined by absorbance and PL (15, 83). The CdSe QD cores were washed and then shelled with CdS following a protocol adapted from those previously reported, where Cd and S precursors were slowly injected via a dual-syringe pump (15, 84, 85).…”

“…Briefly, CdSe cores were synthesized from a protocol adapted from those previously reported, where Cd and Se precursors were reacted with various coordinating ligands where after a brief nucleation step at elevated temperature, the nanocrystals were annealed for up to 2 hours to achieve desired core size, as determined by absorbance and PL (15, 83). The CdSe QD cores were washed and then shelled with CdS following a protocol adapted from those previously reported, where Cd and S precursors were slowly injected via a dual-syringe pump (15, 84, 85). The final CdSe/CdS core/shell QDs were then encapsulated into self-assembled micelles formed by a polymerized phospholipid ligand with a bis-sulfone functional group (PE:PEG:bis-sulfone).…”

“…Typically, VLNPs are constructed with hydrophobic cores loaded with conventional fluorophores or contain fluorescent protein constructs (10)(11)(12). These fluorophores, however, can be limited by smaller absorption cross sections, poor photostability, and low overall brightness that make single-molecule detection and extended biological studies challenging (13)(14)(15). These limitations can be addressed by incorporating fluorescent inorganic nanoparticles, such as quantum dots (QDs), into VLNPs (16)(17)(18).…”

CdS Quantum Dots as Potent Photoreductants for Organic Chemistry Enabled by Auger Recombination

“…Semiconductor quantum dots (QDs) combine advantageous aspects of both homogeneous (high surface-volume ratio, solubility in reaction media, light penetration) and heterogeneous (durability, substrate binding) catalysts, and therefore offer new opportunities for photoredox catalysis. 25,26 QDs have proven to be robust fluorophores and photocatalysts, generally exhibiting superior photostability to small-molecule dyes, [27][28][29][30][31][32][33] however applications of QDs to organic synthesis remain underexplored. To address the need for continued development of photoredox catalysts, our group and others have been interested in new applications of QDs in organic chemistry.…”