Mussel foot proteins (Mfps) show strong adhesion to underwater substrates, making mussels tightly cling to reefs to withstand the sea current. Therefore, Mfps-inspired tissue adhesives have aroused ...much research interest, but tough underwater biological tissue adhesion is still a great challenge. Herein, we report a tough and reversible wet tissue-selective adhesive hydrogel made of poly(acrylic acid-co-catechol) and chitosan (CS). It provides negatively charged -COO
, positively charged -NH
, catechol group and hydrophobic alkyl chain, resemble amino acids, catechol and hydrophobic units in Mfps. Due to the covalent/electrostatic attraction/π-π/cationic-π/hydrogen bonding, in addition to the hydrophobic interaction from the long hydrophobic alkyl chain of the catechol derivative, the hydrogel has a high cohesion strength and toughness, i.e., tensile stress, fracture strain and fracture toughness of ∼0.57 MPa, 2510% and 6620 J m
, respectively. As a tissue adhesive, its adhesion bonding to the porcine skin surface is so strong that its adhesion strength is almost equal to the tearing strength of the hydrogel. The 180-degree peeling adhesion energy of the hydrogel to blood-wetted porcine skin is notably ∼1010 J m
. It can tightly and seamlessly adhere to the porcine small intestine, and has a bursting pressure of up to 520 mmHg. The hydrogel can be handily debonded from the porcine skin surface in the presence of aqueous solution at pH 8.0, and its adhesiveness is reversible for at least 20 cycles. It is supposed that the synergistic interactions of the adhesive catechol group, displacement of water on the wet skin surface by the positively charged -NH
groups of CS and the water-repelling potential of the hydrophobic unit of the catechol derivative, the protection of the catechol group from oxidation into a less adhesive quinone group, and the energy dissipation capacity of the mechanically tough hydrogel contribute to the strong and repeatable wet tissue adhesion.
Purely organic molecules, which emit light by dual emissive (DE) pathways, have received increased attention in the last decade. These materials are now being utilized in practical optoelectronic, ...sensing and biomedical applications. In order to further extend the application of the DE emitters, it is crucial to gain a fundamental understanding of the links between the molecular structure and the underlying photophysical processes. This review categorizes the types of DE according to the spin multiplicity and time range of the emission, with emphasis on recent experimental advances. The design rules towards novel DE molecular candidates, the most perspective types of DE and possible future applications are outlined. These exciting developments highlight the opportunities for new materials synthesis and pave the way for accelerated future innovation and developments in this area.
In the past 30 years, researchers have worked towards reducing the size of ordinary three-dimensional (3D) materials into 1D or 2D materials in order to obtain new properties and applications of ...these low-dimensional systems. Among them, functional nanofibers with large surface area and high porosity have been widely studied and paid attention to. Because of the interesting properties of nanofibers, they find extensive application in filtration, wound dressings, composites, sensors, capacitors, nanogenerators, etc. Recently, a variety of nanofiber preparation methods such as melt blowing, electrospinning (e-spinning), centrifugal spinning and solution blow spinning (SBS) have been proposed. This paper includes a brief review of the fundamental principles of the preparation of nanofibers for solution jet spinning, the influence of experimental parameters, and the properties and potential applications of the solution-blown fibers. And the industrialization and challenges of SBS are also included.
After 45 years of its first observation, surface-enhanced Raman spectroscopy (SERS) has become an ultrasensitive tool applied in chemical analysis, materials science, and biomedical research. ...SERS-active nanomaterials, such as noble metals, transition metals, and semiconductors, have undergone extensive development. The hybridization of semiconductors with plasmonic metal nanomaterials is highly effective in boosting light harvesting and conversion, which enables the rapid growth of metal-semiconductor hybrid nanostructures in SERS-based research fields. With the combination of the unique photoelectric properties and giant SERS signals attributed to the synergistic contribution of plasmons and change transfer (CT), metal-semiconductor heterostructures allow diverse and novel applications of SERS in CT investigations for the rational design of photovoltaic devices and ultrasensitive chemical or biological sensing. In this review, we specifically discuss SERS-active metal-semiconductor heterostructures including their building blocks, enhancement mechanisms, and applications. Moreover, we highlight the current challenges and opportunities for future research in this field based on our recent studies and other related research.
PDF
