Preparation, biological activity and antibacterial properties of tantalum surface-doped Ca2+/Zn2+nanorods.

In this research, we utilize porous tantalum, known for its outstanding elastic modulus and biological properties, as a base material in biomedical applications. The human skeletal system is rich in elements like Ca and Zn. The role of Zn is crucial for achieving a spectrum of sterilizing effects, while Ca is known to effectively enhance cell differentiation and boost cellular activity. The focus of this study is the modification of porous tantalum using a hydrothermal method to synthesize Ca2+/Zn2+-doped Ta2O5nanorods. These nanorods are subjected to extensive characterization techniques to confirm their structure and composition. Additionally, their biological performance is evaluated through a range of tests, including antibacterial assessments, MTT assays, and bacteria/cell scanning electron microscopy (SEM) analyses. The objective is to determine the most effective method of surface modification for porous tantalum, thereby laying a foundational theoretical framework for its surface enhancement.

A three-dimensional (3D) liver-kidney on a chip with a biomimicking circulating system for drug safety evaluation.

The liver and kidney are the major detoxifying organs in the human body and play an important role in pharmacokinetics. Drug-induced hepatotoxicity and nephrotoxicity can cause irreversible damage to the liver and kidney and are a major cause of drug failure in later stages. Both animal models and conventional cell culture have a number of limitations, such as animal ethics and gene mismatching and there is an urgent need to develop a new drug toxicity evaluation approach. In this paper, a 3D liver-kidney on a chip with a biomimicking circulating system (LKOCBCS) was constructed to obtain kidney and liver models in vitro for drug safety evaluation. LKOCBCS, which has a parallel circulating system mimicking biological circulation, consists of 3D biomimetic tissue of liver lobules similar to that of the human liver constructed by 3D bioprinting and renal proximal tubule barriers fabricated by ultrafast laser assisted etching. The proposed LKOCBCS facilitates the communication between the liver and the kidney, including the exchange of nutrients, compounds, and metabolites. The results revealed that the glucose concentration and cell metabolism stabilized after 7 days. A dynamically repeated low-dose administration of cyclosporine A (CsA) was fed to the system, and hepatotoxicity and nephrotoxicity were observed on day 3 according to the changes in toxicity markers. The high levels of drug induced biomarkers expressed in LKOCBCS indicate that this system is more sensitive than the monoculture liver chip and it is highly potential in replacing animal models for effective drug toxicity screening.

Recycling technologies, policies, prospects, and challenges for spent batteries.

The recycling of spent batteries is an important concern in resource conservation and environmental protection, while it is facing challenges such as insufficient recycling channels, high costs, and technical difficulties. To address these issues, a review of the recycling of spent batteries, emphasizing the importance and potential value of recycling is conducted. Besides, the recycling policies and strategies implemented in representative countries are summarized, providing legal and policy support for the recycling industry. Moreover, a comprehensive classification and comparison of recycling technologies identify the characteristics and current status of different approaches. The integrated recycling technology provides a better recycling performance with zero-pollution recycling of spent battery. Biorecycling technology is expected to gain a broad development prospect in the future owing to the superiority of energy-saving and environmental protection, high recycling efficiency, via microbial degradation, enzymatic degradation, etc. Consequently, as for the existing recycling challenges of waste batteries, developing new recycling technology and perfecting its recycling system is an indispensable guarantee for the sustainable development of waste battery. Meanwhile, theoretical support is offered for the recycling of spent batteries.

A Novel Mechanomyography (MMG) Sensor Based on Piezo-Resistance Principle and with a Pyramidic Microarray.

Flexible piezoresistive sensors built by printing nanoparticles onto soft substrates are crucial for continuous health monitoring and wearable devices. In this study, a mechanomyography (MMG) sensor was developed using a flexible piezoresistive MMG signal sensor based on a pyramidal polydimethylsiloxane (PDMS) microarray sprayed with carbon nanotubes (CNTs). The experiment was conducted, and the results show that the sensitivity of the sensor can reach 0.4 kPa-1 in the measurement range of 0~1.5 kPa, and the correlation reached 96%. This has further implications for the possibility that muscle activation can be converted into mechanical movement. The integrity of the sensor in terms of its MMG signal acquisition was tested based on five subjects who were performing arm bending and arm extending movements. The results of this test were promising.

Bioactivity and antibacterial properties of zinc-doped Ta2O5nanorods on porous tantalum surface.

This paper focuses on the preparation of Zn2+-doped Ta2O5nanorods on porous tantalum using the hydrothermal method. Porous tantalum is widely used in biomedical materials due to its excellent elastic modulus and biological activity. Porous tantalum has an elastic modulus close to that of human bone, and its large specific surface area is conducive to promoting cell adhesion. Zinc is an important component of human bone, which not only has spectral bactericidal properties, but also has no cytotoxicity. The purpose of this study is to provide a theoretical basis for the surface modification of porous tantalum and to determine the best surface modification method. The surface structure of the sample was characterized by x-ray diffractometer, x-ray photoelectron spectroscopy, scanning electron microscope, transmission electron microscope, and the Zn-doped Ta2O5nanorods are characterized by antibacterial test, MTT test, ICP and other methods. The sample has good antibacterial properties and no cytotoxicity. The results of this study have potential implications for the development of new and improved biomedical materials.

3D Embedded Printing of Complex Biological Structures with Supporting Bath of Pluronic F-127.

Biofabrication is crucial in contemporary tissue engineering. The primary challenge in biofabrication lies in achieving simultaneous replication of both external organ geometries and internal structures. Particularly for organs with high oxygen demand, the incorporation of a vascular network, which is usually intricate, is crucial to enhance tissue viability, which is still a difficulty in current biofabrication technology. In this study, we address this problem by introducing an innovative three-dimensional (3D) printing strategy using a thermo-reversible supporting bath which can be easily removed by decreasing the temperature. This technology is capable of printing hydrated materials with diverse crosslinked mechanisms, encompassing gelatin, hyaluronate, Pluronic F-127, and alginate. Furthermore, the technology can replicate the external geometry of native tissues and organs from computed tomography data. The work also demonstrates the capability to print lines around 10 µm with a nozzle with a diameter of 60 µm due to the extra force exerted by the supporting bath, by which the line size was largely reduced, and this technique can be used to fabricate intricate capillary networks.

The Additive Manufacturing Approach to Polydimethylsiloxane (PDMS) Microfluidic Devices: Review and Future Directions.

This paper presents a comprehensive review of the literature for fabricating PDMS microfluidic devices by employing additive manufacturing (AM) processes. AM processes for PDMS microfluidic devices are first classified into (i) the direct printing approach and (ii) the indirect printing approach. The scope of the review covers both approaches, though the focus is on the printed mold approach, which is a kind of the so-called replica mold approach or soft lithography approach. This approach is, in essence, casting PDMS materials with the mold which is printed. The paper also includes our on-going effort on the printed mold approach. The main contribution of this paper is the identification of knowledge gaps and elaboration of future work toward closing the knowledge gaps in fabrication of PDMS microfluidic devices. The second contribution is the development of a novel classification of AM processes from design thinking. There is also a contribution in clarifying confusion in the literature regarding the soft lithography technique; this classification has provided a consistent ontology in the sub-field of the fabrication of microfluidic devices involving AM processes.

A High-Linearity Glucose Sensor Based on Silver-Doped Con A Hydrogel and Laser Direct Writing.

A continuous glucose monitoring (CGM) system is an ideal monitoring system for the blood glucose control of diabetic patients. The development of flexible glucose sensors with good glucose-responsive ability and high linearity within a large detection range is still challenging in the field of continuous glucose detection. A silver-doped Concanavalin A (Con A)-based hydrogel sensor is proposed to address the above issues. The proposed flexible enzyme-free glucose sensor was prepared by combining Con-A-based glucose-responsive hydrogels with green-synthetic silver particles on laser direct-writing graphene electrodes. The experimental results showed that in a glucose concentration range of 0-30 mM, the proposed sensor is capable of measuring the glucose level in a repeatable and reversible manner, showing a sensitivity of 150.12 Ω/mM with high linearity of R2 = 0.97. Due to its high performance and simple manufacturing process, the proposed glucose sensor is excellent among existing enzyme-free glucose sensors. It has good potential in the development of CGM devices.

Inflammation Responses to Bone Scaffolds under Mechanical Stimuli in Bone Regeneration.

Physical stimuli play an important role in one tissue engineering. Mechanical stimuli, such as ultrasound with cyclic loading, are widely used to promote bone osteogenesis; however, the inflammatory response under physical stimuli has not been well studied. In this paper, the signaling pathways related to inflammatory responses in bone tissue engineering are evaluated, and the application of physical stimulation to promote osteogenesis and its related mechanisms are reviewed in detail; in particular, how physical stimulation alleviates inflammatory responses during transplantation when employing a bone scaffolding strategy is discussed. It is concluded that physical stimulation (e.g., ultrasound and cyclic stress) helps to promote osteogenesis while reducing the inflammatory response. In addition, apart from 2D cell culture, more consideration should be given to the mechanical stimuli applied to 3D scaffolds and the effects of different force moduli while evaluating inflammatory responses. This will facilitate the application of physiotherapy in bone tissue engineering.

Biocompatible polymers with tunable mechanical properties and conductive functionality on two-photon 3D printing.

Two-photon polymerization (TPP)-based 3D printing technology utilizes the two-photon absorption process of near-infrared radiation, enabling the fabrication of micro- and nano-scale three-dimensional structures with extremely high resolution. It has been widely applied in scientific fields closely related to living organisms, such as tissue engineering, drug delivery, and biosensors. Nevertheless, the existing photoresist materials have poor mechanical tunability and are hardly able to be doped with functional materials, resulting in constraints on the preparation of functional devices with micro-nano structures. In this paper, TPP printable polymer formulas with good mechanical tunability, high resolution, strong functional scalability, and excellent biocompatibility are proposed, by using the synergistic effects of a hydroxyl group-containing photocurable resin prepolymer, UV acrylate monomer, long-chain hydrophilic crosslinking monomer and photo-initiator. This can ensure the printability and help to improve the flexibility of the printed polymer, thereby solving the problem the photosensitive materials suitable for two-photon 3D printing in previous research had in balancing the formability and flexibility. The results of nanoindenter analysis showed that the Young's modulus of the printed structure can be adjusted between 0.3 GPa and 1.43 GPa, realizing mechanical tunability. Also, complex structures, such as micro-scaffold structures and high aspect ratio hollow microneedles were printed to explore the structural stability as well as the feasibility of biodevice application. Meanwhile, the proposed polymer formula can be functionalized to be conductive by doping with functional nanomaterial MXene. Finally, the biocompatibility of the proposed polymer formula was studied by culturing with human normal lung epithelial cells. The results indicated a good potential for biodevice applications.

High-Linearity Hydrogel-Based Capacitive Sensor Based on Con A-Sugar Affinity and Low-Melting-Point Metal.

Continuous glucose monitoring (CGM) plays an important role in the treatment of diabetes. Affinity sensing based on the principle of reversible binding to glucose does not produce intermediates, and the specificity of concanavalin A (Con A) to glucose molecules helps to improve the anti-interference performance and long-term stability of CGM sensors. However, these affinity glucose sensors have some limitations in their linearity with a large detection range, and stable attachment of hydrogels to sensor electrodes is also challenging. In this study, a capacitive glucose sensor with high linearity and a wide detection range was proposed based on a glucose-responsive DexG-Con A hydrogel and a serpentine coplanar electrode made from a low-melting-point metal. The results show that within the glucose concentration range of 0-20 mM, the sensor can achieve high linearity (R2 = 0.94), with a sensitivity of 33.3 pF mM-1, and even with the larger glucose concentration range of 0-30 mM the sensor can achieve good linearity (R2 = 0.84). The sensor also shows resistance to disturbances of small molecules, good reversibility, and long-term stability. Due to its low cost, wide detection range, high linearity, good sensitivity, and biocompatibility, the sensor is expected to be used in the field of continuous monitoring of blood glucose.

Soft-hard hybrid covalent-network polymer sponges with super resilience, recoverable energy dissipation and fatigue resistance under large deformation.

Energy absorption or dissipation ability has been widely developed in tough hydrogels and 3D nano-structured sponges for a variety of applications. However, fully recoverable energy dissipation and fatigue resistance under large deformation is still challenging yet highly desirable. Polymer network with homogeneous chemical crosslinking structures is an efficient way to construct hydrogels with high resilience and fatigue resistance. Unfortunately, such polymer network usually has poor energy dissipation capability. In this paper, we propose a new approach to build the ability of fully recoverable energy dissipation into covalent-crosslink polymer network by integrating soft and hard chains in a uniform crosslinking network and present the one-pot synthesis method for constructing corresponding polymer sponges by low-temperature phase-separation photopolymerization. The application of such polymer sponges as a tissue engineering scaffold, fabricated by using cyclic acetal units and PEG based monomers in particular is demonstrated. For the first time, we show the feasibility of building a synthetic scaffold with the characteristics of high porosity, super compressibility and resilience, fast recovery, completely recoverable energy dissipation, high fatigue resistance, biodegradability and biocompatibility. Such a scaffold is promising in tissue engineering especially in load-bearing applications.

A step towards glucose control with a novel nanomagnetic-insulin for diabetes care.

Massive efforts have been devoted to insulin delivery for diabetes care. Achieving a long-term tight-regulated blood glucose level with a low risk of hypoglycemia remains a great challenge. In this study we propose a novel strategy to efficiently regulate insulin action after insulin is injected or released into patient body aiming to achieve better glycemic control, which is achieved by the administration of insulin-conjugated magnetic nanoparticles (MNPs-Ins). We show that the locomotion of MNPs-Ins can be controlled to reach a target site on an in vitro microfluidic platform, which may open a way to modulate the physiological effect of insulin in a remote-control manner. Most importantly, the in vivo blood glucose regulation of the MNPs-Ins was performed on diabetic mice to understand the glycemic control performance. The results showed that the MNPs-Ins can achieve a better glycemic control with longer effective drug duration while not causing hypoglycemia and a magnetic-modulated hypoglycemic dynamics. Moreover, the in vivo histochemistry experiments confirmed the good biocompatibility of MNPs-Ins. Along with our on-going research on the possibility of the recycle and reuse of the MNPs-Ins, the finding presented in this paper may manifest a fascinating potential in insulin delivery in the near future.

Dielectrophoresis assisted high-throughput detection system for multiplexed immunoassays.

Digital ELISA is introduced as a novel platform with unique advantages for detecting multiple kinds of single-molecule in the sample. How to improve the sensitivity of detection is the direction of current related research. Here, we report an immunoassay method that applied electrokinetic effects to isolate the individual encoded beads and confine in micro-wells to improve the efficiency of cytokines detection simultaneously. The microfluidic design provided a non-uniform electric field to induce dielectrophoresis (DEP) force and to manipulate the beads. Two wavelengths of excitation light excited the encoded beads for simultaneous detection of reporters. The light was confined to the bottom slide via the principle of total internal reflection. Finally, the concentration of captured cytokines was obtained by picking up each bead from the image and then integrating the intensity of fluorescent light emitted from the reporters. The results demonstrated that the fill percentage of encoded beads was raised from 10-20% to 60-80% via DEP effect. By comparing the fluorescence color of the particle, itself and its surface, the concentration of four target cytokines, IL-2, IL-6, IL-10 and TNF-α, were calculated to the pg/ml level. The spike and recovery experiments verified the efficiency, more than 70% of the target molecules were captured. The reliability of our method was verified by flow cytometry as well. In conclusion, we expect the application of DEP can increase the sensitivity of digital ELISA for multiple rapid detection.

Tactile and Thermal Sensors Built from Carbon-Polymer Nanocomposites-A Critical Review.

This paper provides a critical review of tactile and thermal sensors which are built from carbon nanomaterial-filled polymer composites (CNPCs). To make the review more comprehensive and systematic, the sensors are viewed as a system, and a general knowledge architecture for a system called function-context-behavior-principle-state-structure (FCBPSS) is employed to classify information as well as knowledge related to CNPC sensors. FCBPSS contains six basic concepts, namely, F: function, C: context, B: behavior, P: principle, and SS: state and structure. As such, the principle that explains why such composites can work as temperature and pressure sensors, various structures of the CNPC sensor, which realize the principle, and the behavior and performance of CNPC sensors are discussed in this review. This review also discusses the fabrication of the CNPC sensor. Based on the critical review and analysis, the future directions of research on the CNPC sensor are discussed; in particular, the need to have a network of CNPC sensors that can be installed on curved bodies such as those of robots is elaborated.

Parkinson-like early autonomic dysfunction induced by vagal application of DOPAL in rats.

AIM: To understand why autonomic failures, a common non-motor symptom of Parkinson's disease (PD), occur earlier than typical motor disorders. METHODS: Vagal application of DOPAL (3,4-dihydroxyphenylacetaldehyde) to simulate PD-like autonomic dysfunction and understand the connection between PD and cardiovascular dysfunction. Molecular and morphological approaches were employed to test the time-dependent alternation of α-synuclein aggregation and the ultrastructure changes in the heart and nodose (NG)/nucleus tractus solitarius (NTS). RESULTS: Blood pressure (BP) and baroreflex sensitivity of DOPAL-treated rats were significantly reduced accompanied with a time-dependent change in orthostatic BP, consistent with altered echocardiography and cardiomyocyte mitochondrial ultrastructure. Notably, time-dependent and collaborated changes in Mon-/Tri-α-synuclein were paralleled with morphological alternation in the NG and NTS. CONCLUSION: These all demonstrate that early autonomic dysfunction mediated by vagal application of DOPAL highly suggests the plausible etiology of PD initiated from peripheral, rather than central site. It will provide a scientific basis for the prevention and early diagnosis of PD.

Antioxidant status of uric acid, bilirubin, albumin and creatinine during the acute phase after traumatic brain injury: sex-specific features.

BACKGROUND: It is known that the alteration of antioxidants can been seen in early phase after traumatic brain injury (TBI) in order to block oxidative damage, but little is known about the influence of sex on antioxidant system in patients with TBI. This study investigates whether there are sex differences in these endogenous antioxidant agents during the acute phase after TBI and their association with the disease. METHODS: Serum levels of uric acid (UA), bilirubin, albumin and creatinine were measured in 421 individuals included 157 female TBI patients, 156 male TBI patients and 108 age- and sex-matched controls. RESULTS: The statistically significant changes were found in UA, bilirubin, albumin and creatinine for both sexes with TBI, but the trend of changes in bilirubin and creatinine was opposite for gender groups. Serum levels of UA, bilirubin, albumin and creatinine were associated with the severity of TBI patients for both sexes. Male patient subgroups with elevated UA, albumin and creatinine had higher frequency of regaining consciousness in a month. Moreover, addition of UA and creatinine to the established clinical model had significantly improved the predictive performance over using clinical model alone in male patients with TBI. However, no similar findings were observed on female TBI patients. CONCLUSION: Our results suggest sex-based differences in the serum endogenous antioxidant response to TBI. Use of serum UA and creatinine could help in the outcome prediction of male patients with TBI in combination with other prognostic factors.

Three-Dimensional Printing of Calcium Carbonate/Hydroxyapatite Scaffolds at Low Temperature for Bone Tissue Engineering.

Three-dimensional (3D) printing technology has been applied to fabricate bone tissue engineering scaffolds for a wide range of materials with precisely control over scaffold structures. Coral is a potential bone repair and bone replacement material. Due to the natural source limitation of coral, we developed a fabrication protocol for 3D printing of calcium carbonate (CaCO3) nanoparticles for coral replacement in the application of bone tissue engineering. Up to 80% of CaCO3 nanoparticles can be printed with high resolution using poly-l-lactide as a blender. The scaffolds were subjected to a controlled hydrothermal process for incomplete conversion of carbonate to phosphate to produce CaCO3 scaffold covered by hydroxyapatite (HA) to modify the biocompatibility and degradation of CaCO3/HA scaffolds. X-ray diffraction and Fourier transform infrared spectroscopy showed that HA was converted and attached to the surface of the scaffold, and the surface morphology and microstructure were studied using a scanning electron microscope. To confirm the bone regeneration performance of the scaffold, cell proliferation and osteogenic differentiation of MC3T3 cells on the scaffold were evaluated. In addition, in vivo experiments showed that CaCO3/HA scaffolds can promote bone growth and repairing process and has high potential in bone tissue engineering. ClinicalTrials.gov ID: SH9H-2020-A603.

An enzyme-free capacitive glucose sensor based on dual-network glucose-responsive hydrogel and coplanar electrode.

Glucose sensors are vital devices for blood glucose detection in the diabetes care. Different from traditional electrochemical devices based on glucose oxidase, the glucose sensor based on the glucose-responsive hydrogel is more robust owing to its enzyme-free principle. However, integrating the high sensitivity, fast response, wide measuring range and low-cost fabrication into a hydrogel sensor is still challenging. In this study, we present a physical capacitive sensor, which consists of interdigital carbon electrodes (ICEs) fabricated by a direct laser writing technology and glucose-responsive hydrogel (DexG-Con A hydrogel) built by UV curing in situ. The dielectric property of DexG-Con A hydrogel changes accordingly with the change in environmental glucose concentration. Experimental results demonstrate that in a glucose concentration range of 0-30 mM, the proposed hydrogel sensor is capable of measuring the glucose level in a repeatable and reversible manner, showing a short responsive time of less than 2 min and a high sensitivity of 8.81 pF mM-1 at a glucose range of 0-6 mM. Owing to its simple fabrication process, low-cost and high performance, the proposed glucose sensor shows great potential on batch production for continuous glucose monitoring application.

Calcium Carbonate/Gelatin Methacrylate Microspheres for 3D Cell Culture in Bone Tissue Engineering.

Hydrogel microspheres have been widely used as cell carriers and three-dimensional cell culture matrices. However, these microspheres are associated with several unfavorable properties for bone tissue engineering applications, for example, their surface is too smooth to attach cells and they do not contain inorganic materials. This article presents a new method to overcome these disadvantages by depositing CaCO3 crystals on the hydrogel microsphere surface. Specifically, we used a nonplanar flow-focusing microfluidic device to produce gelatin methacrylate (GelMA)-/Na2CO3-based microspheres. We subsequently obtained CaCO3 crystals by a chemical reaction between Na2CO3 and CaCl2. The efficacy of this method was demonstrated by in vitro experiments with human umbilical vein endothelial cells (HUVEC) and immortalized mouse embryonic fibroblasts (iMEF). Cell culture on GelMA/CaCO3 microspheres showed that cells can easily attach and adhere to GelMA/CaCO3 microspheres and maintain high viability. Alkaline phosphatase (ALP) expression was increased as well. These results suggest that this novel microsphere has a high potential for bone tissue engineering applications. Impact statement Microspheres as cell culture substrates have attracted a great deal of attention. The combination of organic and inorganic materials offers the unique merits in bone tissue engineering. In this study, there are two contributions. First, the organic and inorganic material of gelatin methacrylate (GelMA) and CaCO3 were successfully combined, especially, CaCO3 was formed as crystals to enhance cell attachment. Second, microspheres were successfully fabricated with one-step process: that is, the microfluidic technique was coupled with the CaCO3 precipitation in situ. Cell culture shows that the GelMA/CaCO3 microspheres proposed in this study have a high potential for bone tissue engineering applications.