A gadolinium-doped multi-shell upconversion nanoparticle under 800 nm excitation is synthesized with a 10-fold fluorescence-intensity enhancement over that under 980 nm. The nanoformulations exhibit excellent photoacoustic/luminescence/magnetic resonance tri-modal imaging capabilities, enabling visualization of tumor morphology and microvessel distribution at a new imaging depth.

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This meta-analysis suggested that alcohol consumption was associated with an increased risk of periodontitis.

Ischemic stroke (IS) is one of the leading causes of death and accounts for 85% of stroke cases. Since the symptoms are not obvious, diagnosis of IS, particularly at an early stage, is a great challenge. Photoacoustic imaging combines high sensitivity of optical imaging and fine resolution of ultrasonography to non-invasively provide structural and functional information of IS.Methods: We adopted three rapid photoacoustic imaging systems with varying characteristics, including a portable handheld photoacoustic system, high-sensitivity bowl-shaped array photoacoustic computed tomography (PACT), and high-resolution photoacoustic microscopy (PAM) to assess the stereoscopic and comprehensive pathophysiological status of IS at an early stage. Two representative models of IS, referring to photothrombosis and middle cerebral artery occlusion (MCAO) models, were established to verify the feasibility of photoacoustic imaging detection.Results: Non-invasive, rapid PACT of the IS model in mouse provided structural information of the brain lesion, achieving early disease identification (5 min after the onset of disease). Moreover, it was able to dynamically reflect disease progression. Quantitative high-resolution PAM allowed observation of pathological changes in the microvascular system of mouse brain. In terms of functional imaging, significant differences in oxygen saturation (sO2) levels between infarcted and normal areas could be observed by PACT, permitting effective functional parameters for the diagnosis of IS.Conclusions: We used PACT to perform full-view structural imaging and functional imaging of sO2 in IS at the macroscopic level, and then observed the microvascular changes in the infarcted area at the microscopic level by using PAM. This work may provide new tools for the early diagnosis of IS and its subsequent complications as well as assessment of disease progression.

Stem cell migration and interaction with pathology are critical to understand the complexity and status of disease recovery progress. However, the dynamic visualization still remains a great challenge due to imaging technical limitation, cell labeling difficulty, or blood–brain barrier (BBB). Herein, fast photoacoustic tomography (PAT) with optical molecular probes is applied to noninvasively monitor traumatic brain injury (TBI) and its rehabilitation. The vascular distribution and TBI hemorrhage are clearly imaged, longitudinally monitored, and quantified. Bone mesenchymal stem cells (BMSCs) labeled with modified Prussian blue particles (PBPs), excellent near‐infrared dyes and photoacoustic contrasts, are intravenously injected to the mice for improved observation and efficient therapy. BMSCs are demonstrated to be capable of overcoming BBB with enhanced delivery of PBPs to the brain parenchyma. Notably, the versatile BMSCs are observed by PAT to home to the damage region and repair the ruptured vasculature. Moreover, the wound treated by BMSCs exhibits much faster recovery speed than that without treatment. These findings can potentially provide a new noninvasive and high‐resolution approach to image TBI, monitor recovery process, and especially trace BMSCs. This study will stimulate extensive researches on brain diseases and provide promising strategies of dye labeled BMSCs in regenerative medicine.