Gelatin-Based Metamaterial Hydrogel Films with High Conformality for Ultra-Soft Tissue Monitoring

Implantable hydrogel-based bioelectronics(IHB)can precisely monitor human health and diagnose diseases.However,achieving biodegradability,biocompatibility,and high conformality with soft tissues poses significant challenges for IHB.Gelatin is the most suitable candidate for IHB since it is a collagen hydrolysate and a substantial part of the extracellular matrix found naturally in most tissues.This study used 3D printing ultrafine fiber networks with metamaterial design to embed into ultra-low elastic modulus hydrogel to create a novel gelatin-based conductive film(GCF)with mechanical programmability.The regulation of GCF nearly covers soft tissue mechanics,an elastic modulus from 20 to 420 kPa,and a Poisson’s ratio from-0.25 to 0.52.The negative Poisson’s ratio promotes conformality with soft tissues to improve the efficiency of biological interfaces.The GCF can monitor heartbeat signals and respiratory rate by determining cardiac deformation due to its high conformability.Notably,the gelatin characteristics of the biodegradable GCF enable the sensor to monitor and support tissue restoration.The GCF metamaterial design offers a unique idea for bioelectronics to develop implantable sensors that integrate monitoring and tissue repair and a customized method for endowing implanted sensors to be highly conformal with soft tissues.

3D Printing of Tough Hydrogel Scaffolds with Functional Surface Structures for Tissue Regeneration

Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.

A bionic controllable strain membrane for cell stretching at air–liquid interface inspired by papercutting

Lung diseases associated with alveoli,such as acute respiratory distress syndrome,have posed a long-term threat to human health.However,an in vitro model capable of simulating different deformations of the alveoli and a suitable material for mimicking basement membrane are currently lacking.Here,we present an innovative biomimetic controllable strain membrane(BCSM)at an air–liquid interface(ALI)to reconstruct alveolar respiration.The BCSM consists of a high-precision three-dimensional printing melt-electrowritten polycaprolactone(PCL)mesh,coated with a hydrogel substrate—to simulate the important functions(such as stiffness,porosity,wettability,and ALI)of alveolar microenvironments,and seeded pulmonary epithelial cells and vascular endothelial cells on either side,respectively.Inspired by papercutting,the BCSM was fabricated in the plane while it operated in three dimensions.A series of the topological structure of the BCSM was designed to control various local-area strain,mimicking alveolar varied deformation.Lopinavir/ritonavir could reduce Lamin A expression under over-stretch condition,which might be effective in preventing ventilator-induced lung injury.The biomimetic lung-unit model with BCSM has broader application prospects in alveoli-related research in the future,such as in drug toxicology and metabolism.

High-quality assembly and methylome of a Tibetan wild tree peony genome(Paeonia ludlowii)reveal the evolution of giant genome architecture

Tree peony belongs to one of the Saxifragales families,Paeoniaceae.It is one of the most famous ornamental plants,and is also a promising woody oil plant.Although two Paeoniaceae genomes have been released,their assembly qualities are still to be improved.Additionally,more genomes from wild peonies are needed to accelerate genomic-assisted breeding.Here we assemble a high-quality and chromosome-scale 10.3-Gb genome of a wild Tibetan tree peony,Paeonia ludlowii,which features substantial sequence divergence,including around 75%specific sequences and gene-level differentials compared with other peony genomes.Our phylogenetic analyses suggest that Saxifragales and Vitales are sister taxa and,together with rosids,they are the sister taxon to asterids.The P.ludlowii genome is characterized by frequent chromosome reductions,centromere rearrangements,broadly distributed heterochromatin,and recent continuous bursts of transposable element(TE)movement in peony,although it lacks recent whole-genome duplication.These recent TE bursts appeared during the uplift and glacial period of the Qinghai-Tibet Plateau,perhaps contributing to adaptation to rapid climate changes.Further integrated analyses with methylome data revealed that genome expansion in peony might be dynamically affected by complex interactions among TE proliferation,TE removal,and DNA methylation silencing.Such interactions also impact numerous recently duplicated genes,particularly those related to oil biosynthesis and flower traits.This genome resource will not only provide the genomic basis for tree peony breeding but also shed light on the study of the evolution of huge genome structures as well as their protein-coding genes.

Exploring Pre-service Science Teachers' Perspectives on the Nature of Science:A Comparative Study Between China and Canada

The Nature of Science(NOS)is an important component of scientific literacy.Science teachers'Views of the Nature of Science(VNOS)directly affect their teaching behaviors.Therefore,it is of great significance to explore science teachers'VNOs and find ways of improvement.

What They Learned Won't Go Away:The Impacts ofan International Exchange Program on Chinese Teacher Candidates' Understanding of and Practice in Science Education

Purpose:The Canadian university where this study took place has established an international exchange program in teacher education with a large Chinese university.This study was designed to examine how the international exchange program influenced Chinese science teacher candidates'understanding of science education and how such learning impacted their teaching in China.Design/Approach/Methods:The study adopted a qualitative research design with interview and reflective journal as the main approaches for data collection.Findings:Participants greatly appreciated the opportunity of exchange.They reported an improved understanding of Canadian school education and its science curriculum and pedagogy,which changed many aspects of their original values about the relationship between the teacher and students,classroom environment,and so on.Although they faced many constraints to implement what they learned from the exchange in Chinese science classrooms,what they learned had never been forgotten.Participants tried to apply them here and there at the level they could control.Originality/Value:There are many reported studies in the literature about Chinese international students on Western campuses.However,research on Chinese students who participate in international exchange programs is very rare.The findings of this study can inform policymakers and education practitioners about student international exchange programs and benefit future exchange participants.