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Membrane tension is an important physical parameter of describing cellular homeostasis, and it is widely used in the study of cellular processes involving membrane deformation and reorganization, such as cell migration, cell spreading, and cell division. Despite the importance of membrane tension, direct measurement remains difficult. In this work, we developed a ratiometric fluorescent probe sensitive to membrane tension by adjusting the carbon chain structure based on polarity-sensitive fluorophores. The probe is sensitive to changes in membrane tension after cells were subjected to physical or chemical stimuli, such as osmotic shock, lipid peroxidation, and mechanical stress. When the polarity of the plasma membrane increases (the green/red ratio decreases) and the membrane tension increases, the relative magnitude of the membrane tension can be quantitatively calculated by fluorescence ratio imaging. Thus, the probe proved to be an efficient and sensitive membrane tension probe.

ABSTRACT This work experimentally investigated the effects of curing temperatures (7,15,20 and 30°C) on the setting time, strength development, shrinkage, and microstructure of alkali activated slag (AAS). The results indicated [...]

Fluorescence imaging is a useful tool in the field of biomedical applications. However, its imaging capacity is limited by the depth of tissue that can be penetrated when using visible light (400–700 nm) or the first near-infrared window (NIR-I, 700–900 nm). To overcome the problem, fluorescence imaging in the second near-infrared window (NIR-II, 1000–1700 nm) has been developed to reduce photon scattering, auto-absorption and tissue autofluorescence to achieve high spatiotemporal resolution and deep imaging penetration. The key to NIR-II imaging is obtaining and analyzing highly selective information from functional fluorophores that emit in the 1000–1700 nm range. With the rapid development of multidisciplinary research, various types of NIR-II fluorophores have been produced and used in non-invasive, real-time NIR-II biomedical applications. This review summarizes some of the most prevalent NIR-II fluorophores and their synthesis, such as organic fluorophores (OFs), single-walled carbon nanotubes (SWCNTs), quantum dots (QDs), and rare-earth nanoparticles (RENPs). On this basis, we describe the applications of these fluorophores in biomedical fields, including bioimaging, biosensing, phototherapy and surgical navigation. Additionally, major challenges and prospects of NIR-II biomedical application will be further explored.

Developing small‐molecule photothermal agents (PTAs) with good near‐infrared‐II (NIR‐II) response for deeper tissue penetration and minimizing damage to healthy tissues has attracted much attention in photothermal therapy (PTT). However, concentrating ultra‐long excitation wavelengths and high photothermal conversion efficiencies (PCEs) into a single organic small molecule is still challenging due to the lack of suitable molecular structures. Here, six polymethine cyanine molecules based on the structure of indocyanine green are synthesized by increasing the conjugated structure of the two‐terminal indole salts and the number of rigid methine units, and incorporating longer alkyl side chains into the indole salts. Ultimately, IC‐1224 is obtained with an absorption wavelength of more than 1200 nm, which has a high PCE up to 83.2% in the NIR‐II window and exhibits excellent PTT tumor ablation performance. This provides a high‐performance NIR‐II‐responsive PTA, and offers further possibilities for the application of PTT in biomedical fields. IC‐1224 is synthesized with an absorption wavelength of more than 1200 nm, which has a photothermal conversion efficiency of 83.2% in the NIR‐II window and exhibits excellent photothermal therapy (PTT) tumor ablation performance. This high‐performance NIR‐II‐responsive photothermal agent provides more possibilities for the in‐depth application of PTT in biomedical fields.

The serious threat that cancer poses to human health highlights the significance of early detection and effective treatment. The integration of fluorescence diagnosis and photothermal therapy in NIR‐II has gained attention due to its high sensitivity, fast response, and noninvasiveness. Fluorescence, produced by the radiative relaxation process of electrons in a molecule, and photothermal, generated by the nonradiative relaxation process of electrons in a molecule, are competing photophysical processes. Hence, it is a challenge for the molecule to balance between the properties of fluorescence and photothermal. In this study, a NIR‐II hemicyanine with TICT character is designed to obtain molecules with both better fluorescence and photothermal properties, utilizing positively charged pyridine salt and triphenylamine as electron acceptor and donor, respectively, and oxole as the conjugated π‐bridge. HCY‐995, one of the synthesized compounds, has a quantum yield of 0.09%, photothermal conversion efficiency of 54.90%, and a significant Stoke shift of 232 nm, which makes it appropriate for the integration of photothermal therapy and high‐resolution imaging. This study provides new insights into the development of NIR‐II molecules with fluorescent and photothermal integrated properties. In this work, twisted intramolecular charge transfer properties of molecules are regulated by controlling the number of oxoles, so as to synthesize near‐infrared hemicyanine with large Stoker shift, high fluorescence brightness and good photothermal conversion coefficient, which can be used for tumor diagnosis and treatment at the same time.

PNA012 is a new nucleating agent on polybutylene terephthalate. The effect of different dosage of PNA012 on crystallization and mechanical properties were investigated by means of differential scanning calorimetry, universal testing machine, melt flow indexer and vicat softening testing machine. It was revealed that the PNA012 could substantially accelerate the crystallization of PBT. Compared with the pure PBT,the crystallization temperature of PBT/PNA012 rises from 196.3 ℃ to 199.7 ℃ and crystallization degree from 34.2% to 39.9%. The tensile Strength of PBT/PNA012 is increased 9.7%. The Bending Strength has a rise of 9.3% and the heat distortion temperatures of PBT/PNA012 is increased from 115.07℃ to 125.94℃.

Abstract. The effect of styrene-The effect of hydroxy-terminated polybutadiene liquid rubber (HTPB) and softened agent on the performance of epoxy resin are studied. The mechanical properties of the composites investigated and the toughening mechanism were studied trough the SEM. In the HTPB/epoxy resin composites, the hardness is reduced but the elongation and the shear strength increased . Added 20wt%HTPB, the breaking elongation can be up to 16.19% and the shear strength rise to 13.74MPa. From the images of the SEM, the globular and trumpet-like hole and shear zone can hinder the development of the cracks, thus increasing the toughness of the epoxy resint. In the softened agent/epoxy resin composites, The addition of the softened agent, the breaking elongation and the impact strength have increased. From the images of SEM,we found that ,with the addition of the softened agent ,the single phase structure turns to two-phase structure and the bicontinuous phase and the brittle fracture turns to ductile fracture.