Intrinsic and strain dependent ultralow thermal conductivity in novel AuX (X = Cu, Ag) monolayers for outstanding thermoelectric applications.

A large power factor and ultralow lattice thermal conductivity in 2D-monolayers of AuX (X = Cu and Ag) are achieved via first principles calculations. Low phonon frequency, small Debye temperature and high Gruneisen parameter limit the intrinsic thermal conductivity of both the studied materials. An ultra-low lattice thermal conductivity of 0.13 (0.30) W m-1 K-1 and 0.66 (1.59) W m-1 K-1 is obtained for unstrained AuCu and AuAg monolayers, respectively, at 700 (300) K, which further reduces to 0.04 (0.09) and 0.26 (0.63) W m-1 K-1 at 6% biaxial tensile strain. Such values of thermal conductivity are lower than the critical thermal conductivity for the state-of-art thermoelectric materials (kl < 2 W m-1 K-1). The peak values of ZT for unstrained monolayers are 2.20 and 1.40, which enhances to 3.61 and 2.91 at 6% strain for AuCu and AuAg monolayers, respectively. Interestingly pudding-mold band textures are found to be responsible for this unusual thermoelectric behaviour. The stability concerns (chemical/dynamic/mechanical) of these monolayers are ensured to stimulate experimental determinations for novel synthesis and possible applications.

Biomimetic Inspired Hydrogels for Regenerative Vertebral Body Stenting.

PURPOSE OF REVIEW: This review aims to explore the potential of biomimetic hydrogels as an alternative to bone cement in vertebral body stenting (VBS), a minimally invasive treatment for vertebral compression fractures. RECENT FINDINGS: The use of bone cement in VBS procedures can lead to complications such as incomplete fracture reduction and cement leakage. Biomimetic hydrogels have gained significant attention as potential biomaterial alternatives for VBS due to their unique properties, including tuneable therapeutic and mechanical properties. Over the past decade, there has been significant advancements in the development of biomimetic hydrogels for bone regeneration, employing a wide range of approaches to enhance the structural and functional properties of hydrogels. Biomimetic hydrogels hold significant promise as safer and reparative alternatives to bone cement for VBS procedures. However, further research and development in this field are necessary to explore the full potential of hydrogel-based systems for vertebral bone repair.

Effect of Strain on the Electronic Structure and Phonon Stability of SrBaSn Half Heusler Alloy.

This paper presents the strain effects on the structural, electronic and phonon properties of a newly proposed SrBaSn half Heusler compound. Since it is stable considering chemical thermodynamics, we tested its strength against uniform strain w.r.t phonon spectrum and it produces a direct bandgap of 0.7 eV. The direct bandgap reduces to 0.19 eV at -12% strain beyond which the structure is unstable. However, an indirect gap of 0.63 eV to 0.39 eV is observed in the range of +5% to +8% strain and afterwards the strain application destabilizes the structure. From elastic parameters, the ductile nature of this material is observed.

Electronic Structure-, Phonon Spectrum-, and Effective Mass- Related Thermoelectric Properties of PdXSn (X = Zr, Hf) Half Heuslers.

We hereby discuss the thermoelectric properties of PdXSn(X = Zr, Hf) half Heuslers in relation to lattice thermal conductivity probed under effective mass (hole/electrons) calculations and deformation potential theory. In addition, we report the structural, electronic, mechanical, and lattice dynamics of these materials as well. Both alloys are indirect band gap semiconductors with a gap of 0.91 eV and 0.82 eV for PdZrSn and PdHfSn, respectively. Both half Heusler materials are mechanically and dynamically stable. The effective mass of electrons/holes is (0.13/1.23) for Zr-type and (0.12/1.12) for Hf-kind alloys, which is inversely proportional to the relaxation time and directly decides the electrical/thermal conductivity of these materials. At 300K, the magnitude of lattice thermal conductivity observed for PdZrSn is 15.16 W/mK and 9.53 W/mK for PdHfSn. The highest observed ZT value for PdZrSn and PdHfSn is 0.32 and 0.4, respectively.

Nanoscale charge transport and local surface potential distribution to probe defect passivation in Ag doped Cu2ZnSnS4 absorbing layer.

The performance of earth abundant Cu2ZnSnS4 (CZTS) material is limited by high deficit of open circuit voltage (VOC) which is mainly due to the easy formation of CuZn antisite defects. Suppression of CuZn defects is thus inevitably required for further developments in CZTS based solar cells. We studied systematic increase of Ag doping in CZTS thin film and investigated the nanoscale electrical properties using Kelvin probe force microscopy and current sensing atomic force microscopy (CAFM) to probe CuZn defects. Crystallographic analysis indicated the successful partial substitution of Cu+ ions by large size Ag+ ions. The considerable decrease in grain boundary potential from 66.50 ± 5.44 mV to 13.50 ± 2.61 mV with Ag doping, suggesting the substantial decrease in CuZn defects. Consequently, CAFM measurement confirms the remarkable increment in minority carrier current with Ag doping and their local mobility in CZTS layer. Finally, the lower persistent photoconductivity and fast decay response of photogenerated carriers for Ag doped CZTS photodetector further validate our results. This study provides a fresh approach of controlling deleterious CuZn defects in CZTS by tuning Ag content that may guide researchers to develop next generation high-performance CZTS based solar cells.

Nanophotosensitizing through Space Charge Transfer Assemblies of Pentacenequinone Derivative for 'Metal-free' Photoamidation Reactions.

The present study demonstrates the influence of small portion (20 %) of organic co-solvent (DMSO/THF/ACN/MeOH) in mixed aqueous media (80 % water) in controlling the size, quantum yield and life time of the through space charge transfer assemblies (TSCT) of pentacenequinone derivative (TPy-PCQ-TPy). Among various solvent systems [H2 O : DMSO (8 : 2), H2 O : THF (8 : 2), H2 O : ACN (8 : 2) and H2 O : MeOH (8 : 2)] examined, highly emissive (Φf =12 %) and nano-sized assemblies having long life time (3.11 ns) were formed in H2 O : DMSO (8 : 2) solvent system. The solvent dependent differences in the size and excited state properties of TPy-PCQ-TPy assemblies are reflected in their photosensitizing behaviour in different solvent systems. Backed by excellent photosensitizing properties, TPy-PCQ-TPy assemblies smoothly catalyse the photoamidation reactions between unactivated/activated aldehydes and secondary amine under mild reaction conditions (visible light irradiation, aerial atmosphere, room temperature) in H2 O : DMSO (8 : 2) solvent mixture. The as prepared assemblies of TPy-PCQ-TPy also exhibit high potential to catalyse the oxidation of benzyl alcohols to aromatic aldehydes, thus, generating a possibility to use aromatic alcohols as the starting material in photoamidation reactions. The real time application of TSCT assemblies has also been demonstrated in gram scale transformation of aromatic aldehydes to aromatic amides and photooxidation of benzyl alcohol to aromatic aldehyde.

Decellularized extracellular matrix-based bioengineered 3D breast cancer scaffolds for personalized therapy and drug screening.

Breast cancer (BC) is the second deadliest cancer after lung cancer. Similar to all cancers, it is also driven by a 3D microenvironment. The extracellular matrix (ECM) is an essential component of the 3D tumor micro-environment, wherein it functions as a scaffold for cells and provides metabolic support. BC is characterized by alterations in the ECM. Various studies have attempted to mimic BC-specific ECMs using artificial materials, such as Matrigel. Nevertheless, research has proven that naturally derived decellularized extracellular matrices (dECMs) are superior in providing the essential in vivo-like cues needed to mimic a cancer-like environment. Developing in vitro 3-D BC models is not straightforward and requires extensive analysis of the data established by researchers. For the benefit of researchers, in this review, we have tried to highlight all developmental studies that have been conducted by various scientists so far. The analysis of the conclusions drawn from these studies is also discussed. The advantages and drawbacks of the decellularization methods employed for generating BC scaffolds will be covered, and the review will shed light on how dECM scaffolds help develop a BC environment. The later stages of the article will also focus on immunogenicity issues arising from decellularization and the origin of the tissue. Finally, this review will also discuss the biofabrication of matrices, which is the core part of the bioengineering process.

Lead-free alternative cation (Ethylammonium) in organometallic perovskites for thermoelectric applications.

CONTEXT: Hybrid halide perovskites are gaining prominence as a promising option in the advancement of photovoltaic devices. Ethylammonium-based hybrid halide perovskites have demonstrated impressive characteristics, such as a reduced band gap, enhanced stability, and non-toxic properties. In this study, we have explored the structural, electronic, optical, and thermoelectric characteristics of Ethylammonium tin chloride. We have found that Ethylammonium tin chloride (EASnCl3) is a direct wide band gap semiconductor. Additionally, we conducted calculations for various optical parameters, including the dielectric function, absorption coefficient, and refractive index, across a photon energy spectrum ranging from 0 to 7 eV. The research highlights the exceptional qualities of EASnCl3, which exhibits a high absorption coefficient and an elevated Seeback coefficient, among other favorable attributes. These findings position it as a promising material for cost-effective photovoltaic device applications, addressing concerns related to environmental stability. METHODS: Fundamental properties based on the full-potential linearized augmented plane wave (FP-LAPW) method, this computation was performed using the WIEN2k simulation code. We utilized the exchange-correlation potentials PBE-GGA and KTB-mBJ to compute the optimized structure, density of states, and band structure of the material. In order to calculate the thermoelectric properties of the material, the Boltztrap simulation tool has been used. There are several critical absorbance parameters, including the Seeback coefficient, figure of merit, power factor, electrical conductivity, and thermal conductivity, concerning their carrier concentration and chemical potential, that have been taken into consideration.

Surface engineered nanodiamonds: mechanistic intervention in biomedical applications for diagnosis and treatment of cancer.

In terms of biomedical tools, nanodiamonds (ND) are a more recent innovation. Their size typically ranges between 4 to 100 nm. ND are produced via a variety of methods and are known for their physical toughness, durability, and chemical stability. Studies have revealed that surface modifications and functionalization have a significant influence on the optical and electrical properties of the nanomaterial. Consequently, surface functional groups of NDs have applications in a variety of domains, including drug administration, gene delivery, immunotherapy for cancer treatment, and bio-imaging to diagnose cancer. Additionally, their biocompatibility is a critical requisite for theirin vivoandin vitrointerventions. This review delves into these aspects and focuses on the recent advances in surface modification strategies of NDs for various biomedical applications surrounding cancer diagnosis and treatment. Furthermore, the prognosis of its clinical translation has also been discussed.

Selenium nanoparticle-functionalized injectable chitosan/collagen hydrogels as a novel therapeutic strategy to enhance stem cell osteoblastic differentiation for bone regeneration.

Stem cells are an essential consideration in the fields of tissue engineering and regenerative medicine. Understanding how nanoengineered biomaterials and mesenchymal stem cells (MSCs) interact is crucial for their role in bone regeneration. Taking advantage of the structural stability of selenium nanoparticles (Se-NPs) and biological properties of natural polymers, Se-NPs-functionalized, injectable, thermoresponsive hydrogels with an interconnected molecular structure were prepared to identify their role in the osteogenic differentiation of different types of mesenchymal stem cells. Further, comprehensive characterization of their structural and biological properties was performed. The results showed that the hydrogels undergo a sol to gel transition with the help of ß-glycerophosphate, while functionalization with Se-NPs significantly enhances their biological response through stabilizing their polymeric structure by forming Se-O covalent bonds. Further results suggest that Se-NPs enhance the differentiation of MSCs toward osteogenic lineage in both the 2D as well as 3D. We demonstrated that the Se-NPs-functionalized hydrogels could enhance the differentiation of osteoporotic bone-derived MSCs. We also focused on specific cell surface marker expression (CD105, CD90, CD73, CD45, CD34) based on the exposure of healthy rats' bone marrow-derived stem cells (BMSCs) to the Se-NP-functionalized hydrogels. This study provides essential evidence for pre-clinical/clinical applications, highlighting the potential of the nanoengineered biocompatible elastic hydrogels for bone regeneration in diseased bone.

Correction: Selenium nanoparticle-functionalized injectable chitosan/collagen hydrogels as a novel therapeutic strategy to enhance stem cell osteoblastic differentiation for bone regeneration.

Correction for 'Selenium nanoparticle-functionalized injectable chitosan/collagen hydrogels as a novel therapeutic strategy to enhance stem cell osteoblastic differentiation for bone regeneration' by Khaled Alajmi et al., J. Mater. Chem. B, 2024, 12, 9268-9282, https://doi.org/10.1039/D4TB00984C.

Advances in the Development of Nano-Engineered Mechanically Robust Hydrogels for Minimally Invasive Treatment of Bone Defects.

Injectable hydrogels were discovered as attractive materials for bone tissue engineering applications given their outstanding biocompatibility, high water content, and versatile fabrication platforms into materials with different physiochemical properties. However, traditional hydrogels suffer from weak mechanical strength, limiting their use in heavy load-bearing areas. Thus, the fabrication of mechanically robust injectable hydrogels that are suitable for load-bearing environments is of great interest. Successful material design for bone tissue engineering requires an understanding of the composition and structure of the material chosen, as well as the appropriate selection of biomimetic natural or synthetic materials. This review focuses on recent advancements in materials-design considerations and approaches to prepare mechanically robust injectable hydrogels for bone tissue engineering applications. We outline the materials-design approaches through a selection of materials and fabrication methods. Finally, we discuss unmet needs and current challenges in the development of ideal materials for bone tissue regeneration and highlight emerging strategies in the field.

Multi compartmental 3D breast cancer disease model-recapitulating tumor complexity in in-vitro.

Breast cancer is the most common ailment among women. In 2020, it had the highest incidence of any type of cancer. Many Phase II and III anti-cancer drugs fail due to efficacy, durability, and side effects. Thus, accelerated drug screening models must be accurate. In-vivo models have been used for a long time, but delays, inconsistent results, and a greater sense of responsibility among scientists toward wildlife have led to the search for in-vitro alternatives. Stromal components support breast cancer growth and survival. Multi-compartment Transwell models may be handy instruments. Co-culturing breast cancer cells with endothelium and fibroblasts improves modelling. The extracellular matrix (ECM) supports native 3D hydrogels in natural and polymeric forms. 3D Transwell cultured tumor spheroids mimicked in-vivo pathological conditions. Tumor invasion, migration, Trans-endothelial migration, angiogenesis, and spread are studied using comprehensive models. Transwell models can create a cancer niche and conduct high-throughput drug screening, promising future applications. Our comprehensive shows how 3D in-vitro multi compartmental models may be useful in producing breast cancer stroma in Transwell culture.

Exploring the interaction between extracellular matrix components in a 3D organoid disease model to replicate the pathophysiology of breast cancer.

In vitro models are necessary to study the pathophysiology of the disease and the development of effective, tailored treatment methods owing to the complexity and heterogeneity of breast cancer and the large population affected by it. The cellular connections and tumor microenvironments observed in vivo are often not recapitulated in conventional two-dimensional (2D) cell cultures. Therefore, developing 3D in vitro models that mimic the complex architecture and physiological circumstances of breast tumors is crucial for advancing our understanding of the illness. A 3D scaffold-free in vitro disease model mimics breast cancer pathophysiology by allowing cells to self-assemble/pattern into 3D structures, in contrast with other 3D models that rely on artificial scaffolds. It is possible that this model, whether applied to breast tumors using patient-derived primary cells (fibroblasts, endothelial cells, and cancer cells), can accurately replicate the observed heterogeneity. The complicated interactions between different cell types are modelled by integrating critical components of the tumor microenvironment, such as the extracellular matrix, vascular endothelial cells, and tumor growth factors. Tissue interactions, immune cell infiltration, and the effects of the milieu on drug resistance can be studied using this scaffold-free 3D model. The scaffold-free 3D in vitro disease model for mimicking tumor pathophysiology in breast cancer is a useful tool for studying the molecular basis of the disease, identifying new therapeutic targets, and evaluating treatment modalities. It provides a more physiologically appropriate high-throughput platform for screening large compound library in a 96-384 well format. We critically discussed the rapid development of personalized treatment strategies and accelerated drug screening platforms to close the gap between traditional 2D cell culture and in vivo investigations.

Nowotny-Juza phase KBeX (X = N, P, As, Sb, and Bi) half-Heusler compounds: applicability in photovoltaics and thermoelectric generators.

In the present research, we have considered KBeX (X = N, P, As, Sb, and Bi) half-Heusler compounds to study their inherent properties and have used FP-LAPW + lo scheme with density functional theory based WIEN2k package. The structural and band structural parameters have been explained, and various optical, thermoelectric, and thermodynamic parameters of half-Heuslers have also been analyzed in detail. The trend followed by the lattice constant of these materials approves the reliability of this investigation. The band structures show all the materials are direct band gap semiconductors except KBeN. Here, we have noticed that absorption is highest, and optical conductivity is also highest, confirming the theoretical concept and thus the accuracy of the projected outcomes. All materials (except KBeBi) show a figure of merit near unity in both p- and n-regions, and a small decay is observed with increasing temperature, which affirms their potential as thermoelectric candidates in both p- and n-regions at room temperature. Since conventional resources are limited in nature and their vanishing rate is more than their reproduction rate, hence to fulfil the high energy demand, it has become necessary to search for renewable energy resources. Herein, the values of optical and thermoelectric parameters confirm the photovoltaic and thermoelectric applications of these materials.

Onion anthocyanins: Extraction, stability, bioavailability, dietary effect, and health implications.

Anthocyanins are high-value compounds, and their use as functional foods and their natural colorant have potential health benefits. Anthocyanins seem to possess antioxidant properties, which help prevent neuronal diseases and thereby exhibit anti-inflammatory, chemotherapeutic, cardioprotective, hepatoprotective, and neuroprotective activities. They also show different therapeutic effects against various chronic diseases. Anthocyanins are present in high concentrations in onion. In recent years, although both conventional and improved methods have been used for extraction of anthocyanins, nowadays, improved methods are of great importance because of their higher yield and stability of anthocyanins. In this review, we compile anthocyanins and their derivatives found in onion and the factors affecting their stability. We also analyze different extraction techniques of anthocyanins. From this point of view, it is very important to be precisely aware of the impact that each parameter has on the stability and subsequently potentiate its bioavailability or beneficial health effects. We present up-to-date information on bioavailability, dietary effects, and health implications of anthocyanins such as antioxidant, antidiabetic, anticancerous, antiobesity, cardioprotective, and hepatoprotective activities.

Injectable chitosan/collagen hydrogels nano-engineered with functionalized single wall carbon nanotubes for minimally invasive applications in bone.

Mechanical robustness is an essential consideration in the development of hydrogel platforms for bone regeneration, and despite significant advances in the field of injectable hydrogels, many fail in this regard. Inspired by the mechanical properties of carboxylated single wall carbon nanotubes (COOH-SWCNTs) and the biological advantages of natural polymers, COOH-SWCNTs were integrated into chitosan and collagen to formulate mechanically robust, injectable and thermoresponsive hydrogels with interconnected molecular structure for load-bearing applications. This study presents a complete characterisation of the structural and biological properties, and mechanism of gelation of these novel formulated hydrogels. Results demonstrate that ß-glycerophosphate (ß-GP) and temperature play important roles in attaining gelation at physiological conditions, and the integration with COOH-SWCNTs significantly changed the structural morphology of the hydrogels to a more porous and aligned network. This led to a crystalline structure and significantly increased the mechanical strength of the hydrogels from kPa to MPa, which is closer to the mechanical strength of the bone. Moreover, increased osteoblast proliferation and rapid adsorption of hydroxyapatite on the surface of the hydrogels indicates increased bioactivity with addition of COOH-SWCNTs. Therefore, these nano-engineered hydrogels are expected to have wide utility in the area of bone tissue engineering and regenerative medicine.

Maximizing Short Circuit Current Density and Open Circuit Voltage in Oxygen Vacancy-Controlled Bi1-xCaxFe1-yTiyO3-δ Thin-Film Solar Cells.

Designing solid-state perovskite oxide solar cells with large short circuit current (JSC) and open circuit voltage (VOC) has been a challenging problem. Epitaxial BiFeO3 (BFO) films are known to exhibit large VOC (>50 V). However, they exhibit low JSC (≪µA/cm2) under 1 Sun illumination. In this work, taking polycrystalline BiFeO3 thin films, we demonstrate that oxygen vacancies (VO) present within the lattice and at grain boundary (GB) can explicitly be controlled to achieve high JSC and VOC simultaneously. While aliovalent substitution (Ca2+ at Bi3+ site) is used to control the lattice VO, Ca and Ti cosubstitution is used to bring out only GB-VO. Fluorine-doped tin oxide (FTO)/Bi1-xCaxFe1-yTiyO3-δ/Au devices are tested for photovoltaic characteristics. Introducing VO increases the photocurrent by four orders (JSC ∼ 3 mA/cm2). On the contrary, VOC is found to be <0.5 V, as against 0.5-3 V observed for the pristine BiFeO3. Ca and Ti cosubstitution facilitate the formation of smaller crystallites, which in turn increase the GB area and thereby the GB-VO. This creates defect bands occupying the bulk band gap, as inferred from the diffused reflection spectra and band structure calculations, leading to a three-order increase in JSC. The cosubstitution, following a charge compensation mechanism, decreases the lattice VO concentration significantly to retain the ferroelectric nature with enhanced polarization. It helps to achieve VOC (3-8 V) much larger than that of BiFeO3 (0.5-3 V). It is noteworthy that as Ca substitution maintains moderate crystallite size, the lattice VO concentration dominates GB-VO concentration. Notwithstanding, both lattice and GB-VO contribute to the increase in JSC; the former weakens ferroelectricity, and as a consequence, undesirably, VOC is lowered well below 0.5 V. Using optimum JSC and VOC, we demonstrate that the efficiency ∼0.22% can be achieved in solid-state BFO solar cells under AM 1.5 one Sun illumination.

Elucidating the role of size of hydroxyl apatite particles toward the development of competent antiosteoporotic bioceramic materials: In vitro and in vivo studies.

Osteoporosis caused by overdose of steroids is one of the major concerns for the orthopedic surgeons. Current therapeutic strategies offer limited success due to their inability to regenerate damaged bone at osteoporosis site. Therefore, there is an urgent need to develop a material having bone regeneration ability and also, ability to cure osteoporosis simultaneously. In this work, nanosized and microsized hydroxyl apatite (HAp) particles doped with europium (Eu) were prepared for diagnostic and therapeutic applications in biomedical engineering. Particles were characterized by X-ray diffraction to confirm the formation of HAp phase and transmission electron microscopy technique has been used to explore the size of microparticle and nanoparticle. In vitro release of antibiotic drug and degradation behavior in two different pHs of phosphate buffered saline was checked. Controlled drug release behavior and conversion of degraded ions into HAp is estimated by Higuchi's and 3D diffusion model, respectively. Osteoporosis was induced in 36 female Wistar rats by administering dexamethasone once a week for four consecutive weeks. Rats were treated with different doses of nano-HAp (25, 50, and 100 µg/kg intravenous single dose) and single dose of microsized HAp (100 µg/kg). After treatment, authors have evaluated sensitive biochemical markers of bone in serum. Continuous improvement in ultimate stiffness and Young's modulus of femur shaft of rats was observed with the increase in the dose of nano-HAp from 25 to 100 µg/kg. Results strongly suggest that europium-doped nano-HAp is more effective for treating severe osteoporosis in humans. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1723-1735, 2019.

Highly elastomeric photocurable silk hydrogels.

A photocurable silk fibroin hydrogel is prepared, for the first time, using natural silk protein fibroin and biophotosensitizer riboflavin. Riboflavin is excited by ultraviolet light to generate a triplet state which is transferred to produce active oxygen radicals with singlet oxygen as the main component. Active oxygen radicals can induce chemical cross-linking of amino-, phenol- and other groups in the silk fibroin macromolecules to form a photocurable hydrogel. The different biophysical characterizations of the gelation of this modified fibroin protein solution were studied by using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, microplate reader and texture analyzer. The aggregate structures, surface morphologies, mechanical properties, light transmission and degradation properties of the gel were studied. The investigations showed that the silk fibroin/riboflavin hydrogels predominantly have random coils or alpha helix structures. These gels show resilience up to 90% after 80% compression and a light transmission of up to 97%. The cell culture experiment exhibits that the hydrogel has a satisfactory cytocompatibility.