Improved imaging modalities are critically needed for optimizing stem cell therapy. Techniques with real-time content to guide and quantitate cell implantation are especially important in applications such as musculoskeletal regenerative medicine. Here, we report the use of silica-coated gold nanorods as a contrast agent for photoacoustic imaging and quantitation of mesenchymal stem cells in rodent muscle tissue. The silica coating increased the uptake of gold into the cell more than 5-fold, yet no toxicity or proliferation changes were observed in cells loaded with this contrast agent. Pluripotency of the cells was retained, and secretome analysis indicated that only IL-6 was disregulated more than 2-fold from a pool of 26 cytokines. The low background of the technique allowed imaging of down to 100 000 cells in vivo. The spatial resolution is 340 μm, and the temporal resolution is 0.2 s, which is at least an order of magnitude below existing cell imaging approaches. This approach has significant advantages over traditional cell imaging techniques like positron emission tomography and magnetic resonance imaging including real time monitoring of stem cell therapy.

Improved imaging modalities are critically needed for optimizing stem cell therapy. Techniques with real-time content to guide and quantitate cell implantation are especially important in applications such as musculoskeletal regenerative medicine. Here, we report the use of silicacoated gold nanorods as a contrast agent for photoacoustic imaging and quantitation of mesenchymal stem cells in rodent muscle tissue. The silica coating increased the uptake of gold into the cell more than 5-fold, yet no toxicity or proliferation changes were observed in cells loaded with this contrast agent. Pluripotency of the cells was retained, and secretome analysis indicated that only IL-6 was disregulated more than 2-fold from a pool of 26 cytokines. The low background of the technique allowed imaging of down to 100 000 cells in vivo. The spatial resolution is 340 μm, and the temporal resolution is 0.2 s, which is at least an order of magnitude below existing cell imaging approaches. This approach has significant advantages over traditional cell imaging techniques like positron emission tomography and magnetic resonance imaging including real time monitoring of stem cell therapy.

Wound healing can be classified into several categories based their severity. There are many modalities to achieve wound healing but, the significant variety in wound types fosters a need to develop more advanced modalities that accelerate the wound healing process. This project developed a smart nanofilm using biocompatible polyelectrolyte nanofilm multilayers (PNMs) with embedded growth factors. PNMs were achieved using nebulization, an expedient tool for nanoassembly. Nebulization significantly reduces deposition time and does note compromise nanofilm characteristics. Oppositely charged PNMs, Chondroitin Sulfate (CS), Protamine Sulfate (PS), Poly‐L‐lysine (PLL) and Poly‐Glutamic acid (PGA), served as effective nanoarchitectures. PNMs (with/without platelet derived growth factor (PDGF) were formed on organtypic keratinocyte cultures (with/without wound creation). PNMs were assembled with PDGF as an active component in deep, double layered, or superficial ten‐layer architectures. AFM analysis demonstrated that heightened surface roughness and thickness is achieved with the nebulization technique when compared to the nanoassembly. Nanofilms further enhanced cell adhesion, proliferation and protein synthesis. The study suggests that bioactive, PNMs, acting as a local drug delivery system and dressing can enhance the initial stages of cutaneous wound healing.Grant Funding Source: National Science Foundation