Bacterial infections remain a leading threat to global health because of the misuse of antibiotics and the rise in drug‐resistant pathogens. Although several strategies such as photothermal therapy and magneto‐thermal therapy can suppress bacterial infections, excessive heat often damages host cells and lengthens the healing time. Here, a localized thermal managing strategy, thermal‐disrupting interface induced mitigation (TRIM), is reported, to minimize intercellular cohesion loss for accurate antibacterial therapy. The TRIM dressing film is composed of alternative microscale arrangement of heat‐responsive hydrogel regions and mechanical support regions, which enables the surface microtopography to have a significant effect on disrupting bacterial colonization upon infrared irradiation. The regulation of the interfacial contact to the attached skin confines the produced heat and minimizes the risk of skin damage during thermoablation. Quantitative mechanobiology studies demonstrate the TRIM dressing film with a critical dimension for surface features plays a critical role in maintaining intercellular cohesion of the epidermis during photothermal therapy. Finally, endowing wound dressing with the TRIM effect via in vivo studies in S. aureus infected mice demonstrates a promising strategy for mitigating the side effects of photothermal therapy against a wide spectrum of bacterial infections, promoting future biointerface design for antibacterial therapy.
Stomatopods are aggressive crustacean predators that use a pair of ultrafast raptorial appendages to strike on prey. This swift movement is driven by a power amplification system comprising components that must be able to repetitively store and release a high amount of elastic energy. An essential component of this system is the saddle structure, in which the elastic energy is stored by bending prior to striking. Here, a comprehensive study that sheds light on the microstructural and chemical designs of the stomatopod's saddle is conducted. MicroCT scans combined with electron microscopy imaging, elemental mapping, high‐resolution confocal Raman microscopy, and nanomechanical mapping show that the saddle is a bilayer structure with sharp changes in chemical composition and mechanical properties between the layers. The outer layer is heavily mineralized whereas the inner layer contains a high content of chitin and proteins, leading to a spatial organization of phases which is optimized for load distribution during saddle bending. The mineralized outer layer sustains compressive stresses, whereas the inner biopolymeric layer provides tensile resistance. These findings reveal that the saddle chemical composition and microstructure have been spatially tuned to generate a stiff, yet flexible structure that is optimized for storage of elastic energy.
Biomineralization, the process by which mineralized tissues grow and harden via biogenic mineral deposition, is a relatively lengthy process in many mineral-producing organisms, resulting in challenges to study the growth and biomineralization of complex hard mineralized tissues. Arthropods are ideal model organisms to study biomineralization because they regularly molt their exoskeletons and grow new ones in a relatively fast timescale, providing opportunities to track mineralization of entire tissues. Here, we monitored the biomineralization of the mantis shrimp dactyl club—a model bioapatite-based mineralized structure with exceptional mechanical properties—immediately after ecdysis until the formation of the fully functional club and unveil an unusual development mechanism. A flexible membrane initially folded within the club cavity expands to form the new club’s envelope. Mineralization proceeds inwards by mineral deposition from this membrane, which contains proteins regulating mineralization. Building a transcriptome of the club tissue and probing it with proteomic data, we identified and sequenced Club Mineralization Protein 1 (CMP-1), an abundant mildly phosphorylated protein from the flexible membrane suggested to be involved in calcium phosphate mineralization of the club, as indicated by in vitro studies using recombinant CMP-1. This work provides a comprehensive picture of the development of a complex hard tissue, from the secretion of its organic macromolecular template to the formation of the fully functional club.
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