Tracking Stem Cells: The Power of Gold Nanocages and Cutting-Edge Microscopy

Industry: This research falls within the biomedical and nanotechnology industries, focusing on innovative methods for tracking stem cells in medical applications.

Challenge: Current stem cell tracking techniques face limitations such as low sensitivity, shallow penetration depth, and potential cytotoxicity from labeling agents. These challenges impede the ability to monitor stem cells effectively post-transplantation in therapeutic applications.

Extraordinary Aspects of the Paper: This study introduces gold nanocages (AuNCs) as a novel contrast agent for labeling human mesenchymal stem cells (hMSCs). AuNCs enable high-resolution, non-invasive tracking of stem cells in both in vitro and in vivo settings using two-photon and photoacoustic microscopy. The study demonstrated that AuNCs do not exhibit significant cytotoxicity and do not impair the stem cells’ differentiation potential, allowing for long-term monitoring without adverse effects.

Equipment & Sensors Used:

GaGe Digitizer: Model CS 14200 by GaGe Applied Technologies, used for digitizing photoacoustic signals.

Transmission Electron Microscope (TEM): FEI Spirit, for characterizing AuNCs.

UV-Vis Spectrometer: Cary 50 by Varian, for recording UV-visible extinction spectra.

Two-Photon Microscope: Zeiss LSM 510 Meta NLO system with Coherent Chameleon Ti laser, for in vitro imaging.

Photoacoustic Microscopy System: Dye Laser (CBR-D, Sirah) with Rhodamine 6G, pumped by 523-nm Nd laser (INNOSLAB, Edgewave).

Ultrasonic Transducer: V214-BB-RM by Olympus NDT, for detecting photoacoustic waves.

Deep Reflection-Mode Photoacoustic Imaging System: Ti laser (LT-2211A; Lotis TII) with Nd laser (LS-2137; Lotis TII), and a 5-MHz central frequency ultrasonic transducer (V308; Panametrics-NDT).