In Situ Shape Control of Thermoplasmonic Gold Nanostars on Oxide Substrates for Hyperthermia-Mediated Cell Detachment

Gold nanostars (AuNSTs) are biocompatible, have large surface areas, and are characterized by high near-infrared extinction, making them ideal for integration with technologies targeting biological applications. We have developed a robust and simple microfluidic method for the direct growth of anisotropic AuNSTs on oxide substrates including indium tin oxide and glass. The synthesis was optimized to yield AuNSTs with high anisotropy, branching, uniformity, and density in batch and microfluidic systems for optimal light-to-heat conversion upon laser irradiation. Surface-enhanced Raman scattering spectra and mesoscale temperature measurements were combined with spatially correlated scanning electron microscopy to monitor nanostar and ligand stability and microbubble formation at different laser fluences. The capability of the platform for generating controlled localized heating was used to explore hyperthermia-assisted detachment of adherent glioblastoma cells (U87-GFP) grafted to the capillary walls. Both flow and laser fluence can be tuned to induce different biological responses, such as ablation, cell deformation, release of intracellular components, and the removal of intact cells. Ultimately, this platform has potential applications in biological and chemical sensing, hyperthermia-mediated drug delivery, and microfluidic soft-release of grafted cells with single-cell specificity.

Citation

Vinnacombe-Willson, G. A., Chiang, N., Scarabelli, L., Hu, Y., Heidenreich, L. K., Li, X., … Jonas, S. J. (2020). In Situ Shape Control of Thermoplasmonic Gold Nanostars on Oxide Substrates for Hyperthermia-Mediated Cell Detachment. ACS Central Science. doi:10.1021/acscentsci.0c01097

Sponsors

The authors thank Prof. Vincent Tung (KAUST) and Prof. H.R. Tseng (UCLA) for helpful comments and discussion, as well as Prof. Bruce Dunn (UCLA) and the Broad Center of Regenerative Medicine & Stem Cell Research for providing access to the instrumentation for the Raman measurements. Facility support was provided by the UCLA Clinical and Translational Science Institute (CTSI) Core Voucher Program supported through Grant Number UL1TR001881. L.S. thanks the American-Italian Cancer Foundation for fellowship support. N.C. thanks the NIH NIBIB for the Pathway to Independence Award (K99EB028325). Y.G. thanks the UCLA Department of Chemistry & Biochemistry for funding through the SG Fellowship. X.L. thanks the UCLA Cross-Disciplinary Scholars in Science & Technology program. S.J.J. is supported by the NIH Common Fund through a NIH Director’s Early Independence Award cofunded by the National Institute of Dental and Craniofacial Research and Office of the Director, NIH Grant DP5OD028181. S.J.J. also acknowledges Young Investigator Award funds from the Alex’s Lemonade Stand Foundation for Childhood Cancer Research, the Hyundai Hope on Wheels Foundation for Pediatric Cancer Research, and the Tower Cancer Research Foundation. Confocal laser scanning microscopy was performed at the Advanced Light Microscopy/Spectroscopy Laboratory and the Leica Microsystems Center of Excellence at the California NanoSystems Institute (CNSI) at UCLA with funding support from NIH Shared Instrumentation Grant S10OD025017 and NSF Major Research Instrumentation Grant CHE-0722519. Special thanks to Dr. Laurent Bentolila, Dr. Michael Lake, and Dr. Matthew Schibler for their helpful discussions and instrumentation support critical to the completion of this work. The authors acknowledge the use of instruments at the Electron Imaging Center for NanoMachines supported by NIH (1S10RR23057) and CNSI at UCLA. We dedicate this paper to Prof. Laura Kiessling as part of a special collection, on the occasion of her birthday.