Strong near-infrared (NIR) absorption of reduced graphene oxide (rGO) make this material a candidate for photothermal therapy. The use of rGO has been limited by low stability in aqueous media due to the lack of surface hydrophilic groups. We report synthesis of a novel form of reduced graphene-arginine (rGO-Arg) as a nanoprobe. Introduction of Arg to the surface of rGO not only increases the stability in aqueous solutions but also increases cancer cell uptake. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) images are recorded to characterize the morphology of rGO-Arg. Fourier transform infrared (FTIR), X-ray photoelectron spectra (XPS), Raman, and UV-vis spectroscopy are utilized to analyze the physiochemical properties of rGO-Arg. Interaction of rGO-Arg with 808 nm laser light has been evaluated by measuring the absorption cross section in response to periodically modulated intensity to minimize artifacts arising from lateral thermal diffusion with a material scattering matched to a low scattering optical standard. Cell toxicity and cellular uptake by MD-MB-231 cell lines provide supporting data for the potential application of rGO-Arg for photothermal therapy. Absorption cross-section results suggest rGO-Arg is an excellent NIR absorber that is 3.2 times stronger in comparison to GO.

Stimuli sensitive hybrid nanoparticles have been synthesized using a layer-by-layer technique and demonstrated for dual chemo-photothermal destruction of breast cancer cells. The hybrid nanoparticles are composed of alternating layers of graphene oxide and graphene oxide conjugated poly-l-lysine coating the surface of a thermosensitive cationic liposome containing doxorubicin as a core. Data suggests that the hybrid nanoparticles may offer many advantages for chemo-photothermal therapy. Advantages include a decrease of the initial burst release which may result in the reduction in systemic toxicity, increase in pH responsivity around the tumor environment and improved NIR light absorption.

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Photothermal therapy with various nanoparticles, as photothermal transducers, is a widely researched technique. A continuous wave (CW) laser is employed during this procedure. The therapeutic setup is slightly modified to measure the optical absorption cross-section of the graphene oxide (GO), by mitigating the effects of heat diffusion and light scattering. With an 808-nm CW laser setup modulated by a waveform modulation setup, the effect of nanoparticle size and composition of GO in water on optical absorption cross section is characterized.

Background and Objectives: Despite rapid advances and discoveries in medical imaging, monitoring therapeutic efficacy for malignant gliomas and monitoring tumor vasculature remains problematic. The purpose of this study is to utilize optical coherence angiography for vasculature characterization inside and surrounding brain tumors in a murine xenograft brain tumor model. Features included in our analysis include fractional blood volume, vessel tortuosity, diameter, orientation, and directionality. Study Design/Materials and Methods: In this study, five tumorous mice models at 4 weeks of age were imaged. Human glioblastoma cells were injected into the brain and allowed to grow for 4 weeks and then imaged using optical coherence tomography. Results: Results suggest that blood vessels outside the tumor contain a greater fractional blood volume as compared with vessels inside the tumor. Vessels inside the tumor are more tortuous as compared with those outside the tumor. Results indicate that vessels near the tumor margin are directed inward towards the tumor while normal vessels show a more random orientation. Conclusion: Quantification of vascular microenvironments in brain gliomas can provide functional vascular parameters to aid various diagnostic and therapeutic studies. Lasers Surg. Med.

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