Gold Nanoframeworks with Mesopores for Raman–Photoacoustic Imaging and Photo‐Chemo Tumor Therapy in the Second Near‐Infrared Biowindow

Abstract

Gold‐based nanostructures with tunable wavelength of localized surface plasmon resonance (LSPR) in the second near‐infrared (NIR‐II) biowindow receive increasing attention in phototheranostics. In view of limited progress on NIR‐II gold nanostructures, a particular liposome template‐guided route is explored to synthesize novel gold nanoframeworks (AuNFs) with large mesopores (≈40 nm) for multimodal imaging along with therapeutic robustness. The synthesized AuNFs exhibit strong absorbance in NIR‐II region, affording their capacity of NIR‐II photothermal therapy (PTT) and photoacoustic (PA) imaging for deep tumors. Functionalization of AuNFs with hyaluronic acid (HA) endows the targeting capacity for CD44‐overexpressed tumor cells while gatekeeping doxorubicin (DOX) loaded into mesopores. Conjugation of Raman reporter 4‐aminothiophenol (4‐ATP) onto AuNFs yields a surface‐enhanced Raman scattering (SERS) fingerprint for Raman spectroscopy/imaging. In vivo evaluation of HA‐4‐ATP‐AuNFs‐DOX on tumor‐bearing xenografts demonstrates its high efficacy in eradication of solid tumors in NIR‐II under PA–Raman dual image‐guided photo‐chemotherapy. Thus, current AuNFs offer versatile capabilities for phototheranostics.

Degradable and Excretable Ultrasmall Transition Metal Selenide Nanodots for High‐Performance Computed Tomography Bioimaging‐Guided Photonic Tumor Nanomedicine in NIR‐II Biowindow

“…Apart from CT imaging, Rh 3 Se 8 NDs feature strong absorption in NIR and high photothermal‐conversion efficiency, highlighting the great potential in PA imaging. [ 16,21,70–72 ] As displayed in Figure 3c, the Rh 3 Se 8 NDs exhibit an obvious contrast‐enhancement effect on PA imaging in vitro. Furthermore, the 4T1 breast tumor‐bearing mice were intravenously injected with Rh 3 Se 8 NDs and then detected with PA imaging at a given time.…”

“…[ 11–14 ] Additionally, the second near‐infrared biowindow (NIR‐II, 1000–1700 nm) light‐triggered and nanosystems‐enabled photonic hyperthermia have received broad attention as a consequence of the attractive characteristics including low photon scattering and high maximum permissible exposure (MPE, 1064 nm: 1 W cm −2 ; 808 nm: 0.33 W cm −2 ) compared with the first near‐infrared biowindow (NIR‐I, 700–900 nm). [ 15–17 ] Moreover, these nanosystems that could provide high 3D resolution and sensitive imaging signals [e.g., X‐ray computed tomography (CT) imaging, photoacoustic (PA) imaging], and generate hyperthermia effect (temperature of higher than 42 °C) triggered by NIR‐II laser, are the desirable candidate theranostic nanoplatforms for bioimaging‐guided photonic hyperthermia. [ 18–22 ]…”

Development of Second Near-Infrared Photoacoustic Imaging Agents

“…Inorganic Materials Metallic Nanomaterials Metallic nanomaterials, represented by gold, silver, and copper, can achieve high light absorption and excellent photothermal conversion through a localized surface plasmon resonance (LSPR) effect. For example, gold nanostructures are widely used as molecular imaging agents in disease surveillance due to their unique physicochemical and optical properties, such as unique plasma surface absorption, mild surface chemistry, superior biocompatibility, and relative inertness [22][23][24][25][26][27]. To enhance light absorption in the NIR-II region, the main design strategies of gold nanostructures are as follows:…”

Recent advances in applications of multimodal ultrasound-guided photoacoustic imaging technology

“…The advantages of the second near-infrared (NIR-II) PAI are as follows: large penetration depth, low background noise, high maximum allowable irradiation energy and less absorption and scattering by skin tissues, which is conducive to achieving high-resolution imaging of deep tissues [ 18 ]. However, melanin, hemoglobin, and other biological components absorb and scatter light in the first near-infrared (650–970 nm) window, resulting in background interference and spontaneous fluorescence, which can reduce the sensitivity, spatial resolution, and contrast of PAI.…”