Diabetic wound healing is one of the major challenges in the biomedical fields. The conventional single drug treatments have unsatisfactory efficacy, and the drug delivery effectiveness is restricted by the penetration depth. Herein, we develop a magnesium organic framework-based microneedle patch (denoted as MN-MOF-GO-Ag) that can realize transdermal delivery and combination therapy for diabetic wound healing. Multifunctional magnesium organic frameworks (Mg-MOFs) are mixed with poly­(γ-glutamic acid) (γ-PGA) hydrogel and loaded into the tips of MN-MOF-GO-Ag, which slowly releases Mg2+ and gallic acid in the deep layer of the dermis. The released Mg2+ induces cell migration and endothelial tubulogenesis, while gallic acid, a reactive oxygen species-scavenger, promotes antioxidation. Besides, the backing layer of MN-MOF-GO-Ag is made of γ-PGA hydrogel and graphene oxide-silver nanocomposites (GO-Ag) which further enables excellent antibacterial effects for accelerating wound healing. The therapeutic effects of MN-MOF-GO-Ag on wound healing are demonstrated with the full-thickness cutaneous wounds of a diabetic mouse model. The significant improvement of wound healing is achieved for mice treated with MN-MOF-GO-Ag.

and background absorption than that done in the first near-infrared window (NIR-I, 650-950 nm). [1] Therefore, the development of theranostic agents in NIR-II region has become something of a research hotspot. [1a,2] Recently, there is an ever-increasing number of papers describing the modification of gold nanomaterials for NIR-II photoacoustic imaging (PAI) and photothermal therapy (PTT) owing to its unique plasmonic, acoustic, and electric properties, as well as multifunctionality endowed by its various dimensions and morphologies. [1c,e,3] Furthermore, its excellent biosafety surpasses the limits of most inorganic nanomaterials. [4] Currently, there are few methods that shift the localized surface plasmon resonance (LSPR) peak of gold nanomaterials from NIR-I to NIR-II region. [2a,5] For instance, some gold nanorods (GNRs) with superhigh aspect ratios or GNRs with extremely thin shells have been reported. [6] However, most of them still bear poor photostability. In fact, tailoring the morphology is not the only method to obtain a redshift in the absorbance of gold nanomaterials. Substances coated to the surface of GNRs can also cause absorbance red or blueshifts. For example, Wu et al. found that a layer of Cu 2 O could cause absorbance redshift of GNRs from 600 to 800 nm. [7] Yeh et al. developed a rattle-like structure with a GNR encapsulated in a cavity of AuAg nanoshell to achieve a broad absorbance band span 300-1350 nm. [2a] However, most metal oxides suffer from biotoxicity and not responsive to tumor microenvironment. Therefore, the development of biocompatible and stimuli-responsive coatings for plasmonic modulation of GNRs remains a big challenge. Manganese is one of the most commonly used metal element in cancer theranostics on account of its good biosafety and rich quantity of valence states, which allows for the design and synthesis of intelligent theranostic agents. [8] For example, manganese dioxide (MnO 2) is widely used as a catalase to decompose hydrogen peroxide (H 2 O 2) in tumor microenvironment and produce oxygen and hence relieves the tumor hypoxia and reduces tumor resistance to radio-or chemotherapy. [9] Recently, it was reported that MnO 2 could decrease glutathione level in Nanotheranostic agents of gold nanomaterials in the second near-infrared (NIR-II) window have attracted significant attention in cancer management, owing to the reduced background signal and deeper penetration depth in tissues. However, it is still challenging to modulate the localized surface plasmon resonance (LSPR) of gold nanomaterials from the first near-infrared (NIR-I) to NIR-II region. Herein, a plasmonic modulation strategy of gold nanorods (GNRs) through manganese dioxide coating is developed for NIR-II photoacoustic/magnetic resonance (MR) duplex-imaging-guided NIR-II photothermal chemodynamic therapy. GNRs are coated with silica dioxide (SiO 2) and then covered with magnesium dioxide (MnO 2) to obtain the final product of GNR@SiO 2 @MnO 2 (denoted as GSM). The LSPR peak of GNRs could be tuned by adjust...

Thienoisoindigo-based semiconducting polymer with a strong near-infrared absorbance is synthesized and its water-dispersed nanoparticles (TSPNs) are investigated as a contrast agent for photoacoustic (PA) imaging in the second near-infrared (NIR-II) window (1000-1350 nm). The TSPNs generate a strong PA signal in the NIR-II optical window, where background signals from endogenous contrast agents, including blood and lipid, are at the local minima. By embedding a TSPN-containing tube in chicken-breast tissue, an imaging depth of more than 5 cm at 1064 nm excitation is achieved with a contrast-agent concentration as low as 40 µg mL . The TSPNs under the skin or in the tumor are clearly visualized at 1100 and 1300 nm, with negligible interference from the tissue background. TSPN as a PA contrast in the NIR-II window opens new opportunities for biomedical imaging of deep tissues with improved contrast.

Neuromodulation is crucial for the understanding of brain circuits and treatment of neurological diseases. This work demonstrates a new photoacoustic nanoparticlebased neural stimulation technique. Synthesized nanoparticles transduce nearinfrared light to ultrasound locally at the neuronal membrane and evoke neural activation in vitro and in vivo. Through targeting the mechanosensitive ion channel TRPV4, the modified nanotransducers achieve neural activation with enhanced specificity. Together, photoacoustic nanotransducers offer opportunities for nongenetic neuromodulation with deep tissue penetration.

A mathematical model was developed to explain the anomalous penetrant diffusion behavior in glassy polymers. The model equations were derived by using the linear irreversible thermodynamics theory and the kinematic relations in continuum mechanics, showing the coupling between the polymer mechanical behavior and penetrant transport. The Maxwell model was used as the stress–strain constitutive equation, from which the polymer relaxation time was defined. An integral sorption Deborah number was proposed as the ratio of the characteristic relaxation time in the glassy region to the characteristic diffusion time in the swollen region. With this definition, an integral sorption process was characterized by a single Deborah number and the controlling mechanism was identified in terms of the value of the Deborah number. The model equations were two coupled nonlinear differential equations. A finite difference method was developed for solving the model equations. Numerical simulation of integral sorption of penetrants in glassy polymers was performed. The simulation results show that (1) the present model can predict Case II transport behavior as well as the transition from Case II to Fickian diffusion and (2) the integral sorption Deborah number is a major parameter affecting the transition. © 1993 John Wiley & Sons, Inc.