Nanotopographic micro-nano forces finely tune the conformation of macrophage mechanosensitive membrane protein integrin ß2 to manipulate inflammatory responses.

Finely tuning mechanosensitive membrane proteins holds great potential in precisely controlling inflammatory responses. In addition to macroscopic force, mechanosensitive membrane proteins are reported to be sensitive to micro-nano forces. Integrin ß2, for example, might undergo a piconewton scale stretching force in the activation state. High-aspect-ratio nanotopographic structures were found to generate nN-scale biomechanical force. Together with the advantages of uniform and precisely tunable structural parameters, it is fascinating to develop low-aspect-ratio nanotopographic structures to generate micro-nano forces for finely modulating their conformations and the subsequent mechanoimmiune responses. In this study, low-aspect-ratio nanotopographic structures were developed to finely manipulate the conformation of integrin ß2. The direct interaction of forces and the model molecule integrin αXß2 was first performed. It was demonstrated that pressing force could successfully induce conformational compression and deactivation of integrin αXß2, and approximately 270 to 720 pN may be required to inhibit its conformational extension and activation. Three low-aspect-ratio nanotopographic surfaces (nanohemispheres, nanorods, and nanoholes) with various structural parameters were specially designed to generate the micro-nano forces. It was found that the nanorods and nanohemispheres surfaces induce greater contact pressure at the contact interface between macrophages and nanotopographic structures, particularly after cell adhesion. These higher contact pressures successfully inhibited the conformational extension and activation of integrin ß2, suppressing focal adhesion activity and the downstream PI3K-Akt signaling pathway, reducing NF-κB signaling and macrophage inflammatory responses. Our findings suggest that nanotopographic structures can be used to finely tune mechanosensitive membrane protein conformation changes, providing an effective strategy for precisely modulating inflammatory responses. Electronic Supplementary Material: Supplementary material (primer sequences of target genes in RT-qPCR assay; the results of solvent accessible surface area during equilibrium simulation, the ligplut results of hydrogen bonds, and hydrophobic interactions; the density of different nanotopographic structures; interaction analysis of the downregulated leading genes of "focal adhesion" signaling pathway in nanohemispheres and nanorods groups; and the GSEA results of "Rap 1 signaling pathway" and "regulation of actin cytoskeleton" in different groups) is available in the online version of this article at 10.1007/s12274-023-5550-0.

Superiorly Stable Three-Layer Air Microbubbles Generated by Versatile Ethanol-Water Exchange for Contrast-Enhanced Ultrasound Theranostics.

Microbubbles have been widely used as ultrasound contrast agents in clinical diagnosis. Moreover, most current preparation methods for microbubbles are uncontrollable, and the as-obtained microbubbles are unstable in aqueous solution or under ultrasound. Here, we report a strategy to prepare superiorly stable microbubbles with three-layer structures by the ethanol-water exchange. This versatile method can also be applied to prepare different kinds of protein microbubbles with various sizes for advanced biomedical applications. To demonstrate this, the protein air microbubbles are created, which is stable in water for several days with intact structures and exhibits excellent contrast-enhanced ultrasound imaging. Moreover, the protein air microbubbles can also deliver a mass of drugs while maintaining their stable structures, making them a platform for ultrasound imaging-guided drug delivery. The versatile protein air microbubbles have great potential for the design and application of theranostic platforms.

A practical guide to promote informatics-driven efficient biotopographic material development.

Micro/nano topographic structures have shown great utility in many biomedical areas including cell therapies, tissue engineering, and implantable devices. Computer-assisted informatics methods hold great promise for the design of topographic structures with targeted properties for a specific medical application. To benefit from these methods, researchers and engineers require a highly reusable "one structural parameter - one set of cell responses" database. However, existing confounding factors in topographic cell culture devices seriously impede the acquisition of this kind of data. Through carefully dissecting the confounding factors and their possible reasons for emergence, we developed corresponding guideline requirements for topographic cell culture device development to remove or control the influence of such factors. Based on these requirements, we then suggested potential strategies to meet them. In this work, we also experimentally demonstrated a topographic cell culture device with controlled confounding factors based on these guideline requirements and corresponding strategies. A "guideline for the development of topographic cell culture devices" was summarized to instruct researchers to develop topographic cell culture devices with the confounding factors removed or well controlled. This guideline aims to promote the establishment of a highly reusable "one structural parameter - one set of cell responses" database that could facilitate the application of informatics methods, such as artificial intelligence, in the rational design of future biotopographic structures with high efficacy.

Modulating the cobalt dose range to manipulate multisystem cooperation in bone environment: a strategy to resolve the controversies about cobalt use for orthopedic applications.

The paradoxical effect of cobalt on biological processes has aroused controversy regarding the application of cobalt-based biomaterials in bone regeneration. Tuning the dose range of cobalt ions may be a valid strategy to resolve the controversies about cobalt use for orthopedic applications. Recent progress in bone biology has highlighted the effects of multisystem cooperation (especially of osteoimmune, skeletal, and vascular systems) on bone dynamics. Before the application of this dose-tuning strategy, a deeper understanding of its dose-dependent effect on the cooperation of osteoimmune, skeletal, and vascular systems is needed. However, due to the difficulties with investigating the interaction of multiple systems in vitro, the multimodal effects of cobalt on bone homeostasis were investigated here, in an in vivo scenario. Methods: In vitro CCK8 assay and cytoskeletal staining were preformed to detecte the cell cytotoxic reaction in response to 0.1-100 ppm cobalt stimulation. Blood clot containing 0.1 to 5 ppm of cobalt were implanted in the rat calvarium defect. The gene profile of osteoimmune, skeletal, and vascular system as well as the systemic toxicity were evaluated via RT-qPCR, histological analysis and inductively coupled plasma mass spectrometry. The bone regeneration, osteoclastogenesis and vascularization were assessed by micro-ct and histological analysis. Results: Cobalt concentration below 5 ppm did not cause cell toxicity in vitro. No systemic toxicity was observed in vivo at 0.1-5 ppm cobalt concentration. It was found that the early cytokine profiles of the multiple interacting systems were different in response to different cobalt doses. Most of the anti-inflammatory, osteogenic, and proangiogenic factors were upregulated in the 1 ppm cobalt group at the early stage. In the late stage, the 1ppm group was most superior in bone regenerative effect while the 5 ppm group displayed the strongest osteoclastogenesis activity. Conclusions: The 1 ppm concentration of cobalt yielded the most favorable cooperation of the osteoimmune, skeletal, and vascular systems and subsequently optimal bone regeneration outcomes. Tuning the cobalt dose range to manipulate the cooperation of osteoimmune, skeletal, and vascular systems could be a promising and valuable strategy to prevent paradoxical effects of cobalt while preserving its beneficial effects.

Controlled drug release from ultrasound-visualized elastic eccentric microcapsules using different resonant modes.

Ultrasound controlled drug delivery and release has attracted increased attention for targeted delivery of drug. In this report, we present a strategy for targeted drug delivery by using ultrasound to image the location of drug carriers, as well as simultaneously controlling the release rate of drug from elastic eccentric microcapsules (EEMs), based on their mode shapes (MSs) and resonant natural frequencies (NFs). We prepared a series of EEMs with various diameters of inner spherical cavities using a microfluidic chip. The EEMs could be visualized by an ultrasound imaging system within a tissue mimic (i.e. phantom). Using theoretical modeling techniques, we investigated the effects of MSs and NFs on the resonant modes of EEMs. Guided by this modelling, we applied external ultrasonic stimuli at various levels of low frequency to regulate the release rate of Rhodamine 6G (R6G, as a model drug) from EEMs. To further demonstrate the control of drug release and evaluate the efficacy of the encapsulated drugs on cancer cells, we released an anticancer drug, doxorubicin hydrochloride (DOX), from the EEMs and tested the viability of cancer cells in vitro. The results show that this novel strategy holds great promise towards development of a controlled drug release system visualized and triggered by ultrasound.