Bawendi, M. G. | Search bioRxiv

bioRxiv2025

DNA origami directed integration of colloidal nanophotonic materials with silicon photonics

Incorporation of colloidal quantum emitters into silicon-based photonic devices would enable major advances in quantum optics. However, deterministic placement of individual sub-10 nm colloidal particles onto micron-sized photonic structures with nanometer-scale precision remains an outstanding challenge. Here, we introduce Cavity-Shape Modulated Origami Placement (CSMOP) that leverages the structural programmability of DNA origami to precisely deposit colloidal nanomaterials within lithographically-defined resist cavities. CSMOP enables clean and accurate patterning of origami templates onto photonic chips with high yields. Soft-silicification-passivation stabilizes deposited origamis, while preserving their binding sites to attach and align colloidal quantum rods (QRs) to control their nanoscale positions and emission polarization. We demonstrate QR integration with photonic device structures including waveguides, micro-ring resonators, and bullseye photonic cavities. CSMOP therefore offers a general platform for the integration of colloidal quantum materials into photonic circuits, with broad potential to empower quantum science and technology.

bioengineering↗

bioRxiv2017

Shortwave Infrared Fluorescence Imaging with the Clinically Approved Near-Infrared Dye Indocyanine Green

Fluorescence imaging is a method of real-time molecular tracking in vivo that has enabled many clinical technologies. Imaging in the shortwave infrared region (SWIR, 1-2 m) promises higher contrast, sensitivity, and penetration depths compared to conventional visible and near-infrared (NIR) fluorescence imaging. However, adoption of SWIR imaging in clinical settings has been limited, due in part to the absence of FDA-approved fluorophores with peak emission in the SWIR. Here, we show that commercially available NIR dyes, including the FDA-approved contrast agent indocyanine green (ICG), exhibit optical properties suitable for in vivo SWIR fluorescence imaging. Despite the fact that their emission reaches a maximum in the NIR, these dyes can be imaged non-invasively in vivo in the SWIR spectral region, even beyond 1500 nm. We demonstrate real-time fluorescence angiography at wavelengths beyond 1300 nm using ICG at clinically relevant doses. Furthermore, we show tumortargeted SWIR imaging with trastuzumab labeled with IRDye 800CW, a NIR dye currently being tested in multiple phase II clinical trials. Our findings suggest that high-contrast SWIR fluorescence imaging can be implemented alongside existing imaging modalities by switching the detection of conventional NIR fluorescence systems from silicon-based NIR cameras to emerging indium gallium arsenide (InGaAs) SWIR cameras. Using ICG in particular opens the possibility of translating SWIR fluorescence imaging to human clinical applications.

bioengineering↗