Bone, as a mineralized composite of inorganic (mostly carbonated hydroxyapatite) and organic (mainly type I collagen) phases, possesses a unique combination of remarkable strength and toughness. Its ...excellent mechanical properties are related to its hierarchical structures and precise organization of the inorganic and organic phases at the nanoscale: Nanometer‐sized hydroxyapatite crystals periodically deposit within the gap zones of collagen fibrils during bone biomineralization process. This hierarchical arrangement produces nanomechanical heterogeneities, which enable a mechanism for high energy dissipation and resistance to fracture. The excellent mechanical properties integrated with the hierarchical nanostructure of bone have inspired chemists and material scientists to develop biomimetic strategies for artificial bone grafts in tissue engineering (TE). This critical review provides a broad overview of the current mechanisms involved in bone biomineralization, and the relationship between bone hierarchical structures and the deformation mechanism. Our goal in this review is to inspire the application of these principles toward bone TE.
Bone is a hierarchical nanocomposite with excellent mechanical and biological functions that inspires the development of future high‐performance biomaterials. Here, we clarify the hierarchical structures and formation mechanism of bone. Recent progress in the synthesis of biomimetic materials and their potential applications in tissue engineering are also summarized. This review provides a comprehensive perspective for the future fabrication of artificial bone grafts.
Natural bone is a mineralized biological material, which serves a supportive and protective framework for the body, stores minerals for metabolism, and produces blood cells nourishing the body. ...Normally, bone has an innate capacity to heal from damage. However, massive bone defects due to traumatic injury, tumor resection, or congenital diseases pose a great challenge to reconstructive surgery. Scaffold-based tissue engineering (TE) is a promising strategy for bone regenerative medicine, because biomaterial scaffolds show advanced mechanical properties and a good degradation profile, as well as the feasibility of controlled release of growth and differentiation factors or immobilizing them on the material surface. Additionally, the defined structure of biomaterial scaffolds, as a kind of mechanical cue, can influence cell behaviors, modulate local microenvironment and control key features at the molecular and cellular levels. Recently, nano/micro-assisted regenerative medicine becomes a promising application of TE for the reconstruction of bone defects. For this reason, it is necessary for us to have in-depth knowledge of the development of novel nano/micro-based biomaterial scaffolds. Thus, we herein review the hierarchical structure of bone, and the potential application of nano/micro technologies to guide the design of novel biomaterial structures for bone repair and regeneration.
DNA is traditionally known as a central genetic biomolecule in living systems. From an alternative perspective, DNA is a versatile molecular building-block for the construction of functional ...materials, in particular biomaterials, due to its intrinsic biological attributes, molecular recognition capability, sequence programmability, and biocompatibility. The topologies of DNA building-blocks mainly include linear, circular, and branched types. Branched DNA recently has been extensively employed as a versatile building-block to synthesize new biomaterials, and an assortment of promising applications have been explored. In this review, we discuss the progress on DNA functional materials assembled from branched DNA. We first briefly introduce the background information on DNA molecules and sketch the development history of DNA functional materials constructed from branched DNA. In the second part, the synthetic strategies of branched DNA as building-blocks are categorized into base-pairing assembly and chemical bonding. In the third part, construction strategies for the branched DNA-based functional materials are comprehensively summarized including tile-mediated assembly, DNA origami, dynamic assembly, and hybrid assembly. In the fourth part, applications including diagnostics, protein engineering, drug and gene delivery, therapeutics, and cell engineering are demonstrated. In the end, an insight into the challenges and future perspectives is provided. We envision that branched DNA functional materials can not only enrich the DNA nanotechnology by ingenious design and synthesis but also promote the development of interdisciplinary fields in chemistry, biology, medicine, and engineering, ultimately addressing the growing demands on biological and medical-related applications in the real world.
Studies have shown that the outbreak of infectious diseases would result in mental health problems. Females are in greater risk for psychological problems than males. The present study investigated ...gender differences of depression and anxiety and explored associated factors during the COVID-19 epidemic among Chinese social media users.
We recruited 3088 participants through social media cross China. Participants completed sociodemographic and the COVID-19 epidemic related questions, the 2-item Patient Health Questionnaire (PHQ-2), and the 2-item Generalized Anxiety Disorder Scale (GAD-2), the Chinese version of the 10-item Connor-Davidson Resilience Scale. We applied Chi-square test and ANOVA for data description and linear regression analysis for exploring factors associated with depression and anxiety.
Of 3063 participants eligible for analysis, the total prevalence of depression and anxiety was 14.14 and 13.25%. Females were experiencing more severe stress and anxiety symptoms, while males showed better resilience to stress. The severity of depression symptoms would decrease with the increase of age resilience, and it would increase if being unemployed, feeling less adapted, being more stressed. The severity of anxiety symptoms would decrease with higher education and better resilience, and it would increase if being female, spending over 60 min on COVID-19 related information, less adapted, and being more stressed.
The findings show the increased prevalence of depression and anxiety in Chinese population during the COVID-19 epidemic, and females are experiencing more severe anxiety symptoms than males. As social media is the current main resource of information related to COVID-19, interventions should be implemented to help users to limit the time they spend on social media and to get key information related to the epidemic from authoritative and authentic resource to avoid infodemic and prevent mental health problems.
In the early stages of the outbreak of coronavirus disease 2019 (COVID-19) in Hubei, China, the local health-care system was overwhelmed. Physicians and nurses who had no infectious disease expertise ...were recruited to provide care to patients with COVID-19. To our knowledge, no studies on their experiences of combating COVID-19 have been published. We aimed to describe the experiences of these health-care providers in the early stages of the outbreak.
We did a qualitative study using an empirical phenomenological approach. Nurses and physicians were recruited from five COVID-19-designated hospitals in Hubei province using purposive and snowball sampling. They participated in semi-structured, in-depth interviews by telephone from Feb 10 to Feb 15, 2020. Interviews were transcribed verbatim and analysed using Haase's adaptation of Colaizzi's phenomenological method.
We recruited nine nurses and four physicians. Three theme categories emerged from data analysis. The first was “being fully responsible for patients' wellbeing—‘this is my duty’”. Health-care providers volunteered and tried their best to provide care for patients. Nurses had a crucial role in providing intensive care and assisting with activities of daily living. The second category was “challenges of working on COVID-19 wards”. Health-care providers were challenged by working in a totally new context, exhaustion due to heavy workloads and protective gear, the fear of becoming infected and infecting others, feeling powerless to handle patients' conditions, and managing relationships in this stressful situation. The third category was “resilience amid challenges”. Health-care providers identified many sources of social support and used self-management strategies to cope with the situation. They also achieved transcendence from this unique experience.
The intensive work drained health-care providers physically and emotionally. Health-care providers showed their resilience and the spirit of professional dedication to overcome difficulties. Comprehensive support should be provided to safeguard the wellbeing of health-care providers. Regular and intensive training for all health-care providers is necessary to promote preparedness and efficacy in crisis management.
National Key R&D Program of China, Project of Humanities and Social Sciences of the Ministry of Education in China.
Surface enhanced Raman scattering (SERS) is a trace detection technique that extends even to single molecule detection. Its potential application to the noninvasive recognition of lung malignancies ...by detecting volatile organic compounds (VOCs) that serve as biomarkers would be a breakthrough in early cancer diagnostics. This application, however, is currently limited by two main factors: (1) most VOC biomarkers exhibit only weak Raman scattering; and (2) the high mobility of gaseous molecules results in a low adsorptivity on solid substrates. To enhance the adsorption of gaseous molecules, a ZIF‐8 layer is coated onto a self‐assembly of gold superparticles (GSPs) in order to slow the flow rate of gaseous biomarkers and depress the exponential decay of the electromagnetic field around the GSP surfaces. Gaseous aldehydes that are released as a result of tumor‐specific tissue composition and metabolism, thereby acting as indicators of lung cancer, are guided onto SERS‐active GSPs substrates through a ZIF‐8 channel. Through a Schiff base reaction with 4‐aminothiophenol pregrafted onto gold GSPs, gaseous aldehydes are captured with a 10 ppb limit of detection, demonstrating tremendous prospects for in vitro diagnoses of early stage lung cancer.
A high‐sensitivity surface enhanced Raman scattering (SERS) substrate is used for volatile organic compounds (VOCs) detection in exhaled breath, wherein ordered gold superparticles act as SERS hotspots and a metal‐organic‐framework layer is employed to slow the flow rate and strengthen the adsorption of gaseous analytes. Gaseous aldehyde VOCs are captured with a parts per billion limit of detection in this analyte‐detection system.
The growing demand for safe and renewable energy storage systems has driven the recent renaissance of Zn‐ion batteries (ZIBs). Nevertheless, the intrinsic drawbacks of inhomogeneous electric ...distribution and sluggish ion replenishment worsen the Zn dendrite issues that seriously impede their practical application. Herein, for the first time, a functional 3D printed reservoir‐integrated N‐doped carbon host (3DP‐NC) is designed to remodel the electric/ionic fields. The customized 3D printed structure equipped with regular micron‐sized holes induces reduced local current density and homogeneous electric distribution. The micron‐sized holes function as reservoirs to ensure unobstructed ion diffusion and quasi‐steady‐state ionic supplements. A N‐doping interfacial modification strategy is further employed to encourage a highly zincophilic surface, hence reducing the nucleation energy barrier and motivating uniform Zn nucleation. As a result, the Zn‐deposited 3DP‐NC electrode (3DP‐NC@Zn) affords dendrite‐free morphology and highly reversible Zn plating/stripping with an ultra‐small overpotential of 15.3 mV even at 10 mA cm−2. Additionally, these appealing features also endow the 3DP‐NC@Zn electrode with an outstanding lifespan over 380 h at 1 mA cm−2 and 1 mAh cm−2. The thrilling performance establishes a new roadmap that advances the development of dendrite‐free and durable metal batteries by exploiting this unique 3D printing technique.
A 3D‐printing strategy is applied to construct a reservoir‐integrated N‐doped carbon host (3DP‐NC) with remodeled electric/ionic fields. Benefiting from the reduced local current density, homogeneous electric distribution, unobstructed ion diffusion and quasi‐steady‐state ionic supplements, the 3DP‐NC@Zn electrode features highly reversible Zn plating/stripping with ultra‐small overpotential at high current density as well as excellent cycling life span.
Studies on the self‐assembly of nanoparticles have been a hot topic in nanotechnology for decades and still remain relevant for the present and future due to their tunable collective properties as ...well as their remarkable applications to a wide range of fields. The novel properties of nanoparticle assemblies arise from their internal interactions and assemblies with the desired architecture key to constructing novel nanodevices. Therefore, a comprehensive understanding of the interparticle forces of nanoparticle self‐assemblies is a pre‐requisite to the design and control of the assembly processes, so as to fabricate the ideal nanomaterial and nanoproducts. Here, different categories of interparticle forces are classified and discussed according to their origins, behaviors and functions during the assembly processes, and the induced collective properties of the corresponding nanoparticle assemblies. Common interparticle forces, such as van der Waals forces, electrostatic interactions, electromagnetic dipole‐dipole interactions, hydrogen bonds, solvophonic interactions, and depletion interactions are discussed in detail. In addition, new categories of assembly principles are summarized and introduced. These are termed template‐mediated interactions and shape‐complementary interactions. A deep understanding of the interactions inside self‐assembled nanoparticles, and a broader perspective for the future synthesis and fabrication of these promising nanomaterials is provided.
Nanoparticle self‐assemblies are considered highly promising nanomaterials for future industrialization. Here, recent progress in the synthesis of nanoparticle self‐assemblies with respect to interparticle forces, which determine their collective properties, is highlighted. A comprehensive perspective for the future design and fabrication of nanoparticle assemblies with excellent properties and applications is presented.
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•With MGO based materials, the charge transfer resistance Rct is proved to be a more reliable parameter than the impedence Rre for the humidity sensing.•The addition of Nafion ...decreases the charge transfer resistance (Rct) and increases the sensitivity of MGO based sensor.•Linearity of the humidity sensor can be improved by the combination of MGO and Nafion, which also shows better long term stability.
Graphene oxide (GO) and its derivatives have been applied to the humidity sensing area in recent years due to its abundant hydrophilic functional groups, and proved to be ultrasensitive to the humidity changing. But the stability of the sensors is always an obstacle to their application. Besides, the long-term linearity is seldom studied. In this work, diamine modified GO (MGO) has been synthesized and mixed with Nafion polymer to form a hybrid film, and applied to the humidity sensors. We have applied two measurement methods by either fitting of the impedance spectra to extract charge transfer resistance (Rct) or measurement of the impedance under a certain frequency, to evaluate the response to the relative humidity (RH). Both MGO and its composite show good sensitivity to the RH under the two testing methods The Rct shows good linearity at the full testing RH range even after two months, while the impedance under a certain frequency can’t keep the linear response to the RH after certain period of time. The addition of Nafion decreases the Rct and increases the sensitivity of MGO based sensor. Linearity of the sensor is improved by the combination of MGO and Nafion. Long-term testing results show the linearity of the composite sensors changes over time but always keeps a better linearity than the pure MGO sensor.
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