The mechanical loading-deformation relation of elastin and collagen fibril bundles is fundamental to understanding the microstructural properties of tissue. Here, we use multiphoton microscopy to obtain quantitative data of elastin and collagen fiber bundles under in situ loading of coronary adventitia. Simultaneous loading-imaging experiments on unstained fresh coronary adventitia allowed morphometric measurements of collagen and elastin fibril bundles and their individual deformation. Fiber data were analyzed at five different distension loading points (circumferential stretch ratio λ(θ) = 1.0, 1.2, 1.4, 1.6, and 1.8) at a physiological axial stretch ratio of λ(axial) = 1.3. Four fiber geometrical parameters were used to quantify the fibers: orientation angle, waviness, width, and area fraction. The results show that elastin and collagen fibers in inner adventitia form concentric densely packed fiber sheets, and the fiber orientation angle, width, and area fraction vary transmurally. The extent of fiber deformation depends on the initial orientation angle at no-distension state (λ(θ) = 1.0 and λ(axial) = 1.3). At higher distension loading, the orientation angle and waviness of fibers decrease linearly, but the width of collagen fiber is relatively constant at λ(θ) = 1.0-1.4 and then decrease linearly for λ(θ) ≥ 1.4. A decrease of the relative dispersion (SD/mean) of collagen fiber waviness suggests a heterogeneous mechanical response to loads. This study provides fundamental microstructural data for coronary artery biomechanics and we consider it seminal for structural models.

Type-I photodynamic therapy (PDT) with less oxygen consumption shows great potential for overcoming the vicious hypoxia typically observed in solid tumors. However, the development of type-I PDT is hindered by insufficient radical generation and the ambiguous design strategy of type-I photosensitizers (PSs). Therefore, developing highly efficient type-I PSs and unveiling their structure–function relationship are still urgent and challenging. Herein, we develop two phenanthro­[9,10-d]­imidazole derivatives (AQPO and AQPI) with aggregation-induced emission (AIE) characteristics and boost their reactive oxygen species (ROS) generation efficiency by reducing singlet–triplet splitting (ΔE ST). Both AQPO and AQPI show ultrasmall ΔE ST values of 0.09 and 0.12 eV, respectively. By incorporating electron-rich anisole, the categories of generated ROS by AIE PSs are changed from type-II (singlet oxygen, 1O2) to type-I (superoxide anion radical, O2 •– and hydroxyl radical, •OH). We demonstrate that the assembled AQPO nanoparticles (NPs) achieve a 3.2- and 2.9-fold increase in the O2 •– and •OH generation efficiencies, respectively, compared to those of AQPI NPs (without anisole) in water, whereas the 1O2 generation efficiency of AQPO NPs is lower (0.4-fold) than that of AQPI NPs. The small ΔE ST and anisole group endow AQPO with an excellent capacity for type-I ROS generation. In vitro and in vivo experiments show that AQPO NPs achieve an excellent hypoxia-overcoming PDT effect by efficiently eliminating tumor cells upon white light irradiation with good biosafety.

Fluorescent probes capable of in vivo lipids labeling are highly desirable for studying lipid‐accumulation‐related metabolic diseases, such as nonalcoholic fatty liver disease, type‐2 diabetes, and atherosclerosis. However, most of the current lipid‐specific fluorophores cannot be used for in vivo labeling due to their strong hydrophobicity. Herein, organic dots from bright luminogens with aggregation‐induced emission (AIEgen) are developed for in vivo labeling and three‐photon fluorescence imaging of lipid‐rich tissues, such as fatty liver, atherosclerotic plaques in brain vasculatures, and carotid arteries. The organic dots show excellent stability in an aqueous medium with high targeting specificity to lipids and strong three‐photon fluorescence in the far‐red/near‐infrared (NIR) region under NIR‐II laser excitation, which enables efficient in vivo labeling and imaging of lipids in deep tissues. The study will inspire the development of lipid‐targeting fluorophores for in vivo applications.

Bioinspired nanochannel based biosensors have been widely applied for sensing ions, small molecules, and biomolecules. However, the low selectivity and difficulty in recycle sensing still heavily hamper their widespread applications. Herein, we designed and fabricated a nanochannel based biosensor for high-efficiency bisulfite (HSO3 –) sensing and removal through forming a reversible covalent bond between HSO3 – and 4-aminophenyl-phenyl-methanone (APPM). This nanofluidic biosensor displays a promising HSO3 – selectivity with high ion rectification/gating ratio (47 and 5) and excellent reversibility and stability. Of note, the L02 cell line containing excess HSO3 – could still maintain high vitality in the presence of such an APPM-functionalized biosensor based membrane. These results will not only help to better understand the biological function of HSO3 – in living organisms but also inspire us to develop smart artificial nanochannel based biosensors for biological applications.