SEVAR: a stereo event camera dataset for virtual and augmented reality

Event cameras,characterized by their low latency,large dynamic range,and extremely high temporal resolution,have recently received increasing attention.These features make them particularly well-suited for virtual/augmented reality(VR/AR)applications.To facilitate the development of three-dimensional(3D)perception and navigation algorithms in VR/AR applications using event cameras,we introduce the Stereo Event camera dataset for Virtual and Augmented Reality(SEVAR),which comprises a wide variety of head-mounted indoor sequences,including scenarios with rapid motion and a large dynamic range.

Tailoring the multiscale mechanics of tunable decellularized extracellular matrix (dECM) for wound healing through immunomodulation

With the discovery of the pivotal role of macrophages in tissue regeneration through shaping the tissue immune microenvironment, various immunomodulatory strategies have been proposed to modify traditional biomaterials. Decellularized extracellular matrix (dECM) has been extensively used in the clinical treatment of tissue injury due to its favorable biocompatibility and similarity to the native tissue environment. However, most reported decellularization protocols may cause damage to the native structure of dECM, which undermines its inherent advantages and potential clinical applications. Here, we introduce a mechanically tunable dECM prepared by optimizing the freeze-thaw cycles. We demonstrated that the alteration in micromechanical properties of dECM resulting from the cyclic freeze-thaw process contributes to distinct macrophage-mediated host immune responses to the materials, which are recently recognized to play a pivotal role in determining the outcome of tissue regeneration. Our sequencing data further revealed that the immunomodulatory effect of dECM was induced via the mechnotrasduction pathways in macrophages. Next, we tested the dECM in a rat skin injury model and found an enhanced micromechanical property of dECM achieved with three freeze-thaw cycles significantly promoted the M2 polarization of macrophages, leading to superior wound healing. These findings suggest that the immunomodulatory property of dECM can be efficiently manipulated by tailoring its inherent micromechanical properties during the decellularization process. Therefore, our mechanics-immunomodulation-based strategy provides new insights into the development of advanced biomaterials for wound healing.

Nanotopographic micro-nano forces finely tune the conformation of macrophage mechanosensitive membrane protein integrinβ_(2)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.Integrinβ_(2),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 integrinβ_(2).The direct interaction of forces and the model molecule integrinαXβ_(2)was first performed.It was demonstrated that pressing force could successfully induce conformational compression and deactivation of integrinαXβ_(2),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 integrinβ_(2),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.

Improving hard metal implant and soft tissue integration by modulating the“inflammatory-fibrous complex”response

Soft tissue integration is one major difficulty in the wide applications of metal materials in soft tissue-related areas.The inevitable inflammatory response and subsequent fibrous reaction toward the metal implant is one key response for metal implant-soft tissue integration.It is of great importance to modulate this inflammatory-fibrous response,which is mainly mediated by the multidirectional interaction between fibroblasts and macrophages.In this study,macrophages are induced to generate M1 and M2 macrophage immune microenvironments.Their cytokine profiles have been proven to have potentially multi-regulatory effects on fibroblasts.The multi-reparative effects of soft tissue cells(human gingival fibroblasts)cultured on metal material(titanium alloy disks)in M1 and M2 immune microenvironments are then dissected.Fibroblasts in the M1 immune microenvironment tend to aggravate the inflammatory response in a pro-inflammatory positive feedback loop,while M2 immune microenvironment enhances multiple functions of fibroblasts in soft tissue integration,including soft tissue regeneration,cell adhesion on materials,and contraction to immobilize soft tissue.Enlighted by the close interaction between macrophages and fibroblasts,we propose the concept of an“inflammatory-fibrous complex”to disclose possible methods of precisely and effectively modulating inflammatory and fibrous responses,thus advancing the development of metal soft tissue materials.

Bioelectronic modulation of single-wavelength localized surface plasmon resonance (LSPR) for the detection of electroactive biomolecules

The simplification of localized surface plasmon resonance(LSPR) detection can further promote the development of optical biosensing application in point-of-care testing. In this study, we proposed a simple light emitting diode(LED) based single-wavelength LSPR sensor modulated with bio-electron transfers for the detection of electroactive biomolecules. Indium tin oxide electrode loaded with nanocomposites of polyaniline coated gold nanorod was used as LSPR chip, and the applied electric potential was scanned at the LSPR chip for single-wavelength LSPR biosensing. Under the scanning of applied potentials, biological electron transfer of redox reaction was employed to demonstrate the bioelectronic modulation of single-wavelength LSPR for selective electroactive biomolecule detection. Without any additional recognition material, electroactive biomolecules uric acid and dopamine were detected directly with a sensitivity of 5.05 μmol/L and 7.11 μmol/L at their specific oxidation potentials, respectively. With the simplified optical configuration and selective bioelectronic modulation, the single-wavelength LSPR sensor is promising for the development of simple, low-cost, and high specificity optical biosensor for point-of-care testing of electroactive biomolecules.

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.