Microfluidic Assembly of Degradable, Stereocomplexed Hydrogel Microparticles.

Hydrogel microparticles (HMPs) have been investigated widely for their use in tissue engineering and drug delivery applications. However, translation of these highly tunable systems has been hindered by covalent cross-linking methods within microparticles. Stereocomplexation, a stereospecific form of physical cross-linking, provides a robust yet degradable alternative for creating translationally relevant HMPs. Herein, 4-arm polyethylene glycol (PEG) stars were used as macromolecular initiators from which oligomeric poly(l-lactic acid) (PLLA) was polymerized with a degree of polymerization (DPn) of 20 on each arm. Similarly, complementary propargyl-containing ABA cross-linkers with enantiomeric poly(d-lactic acid) (PDLA) segments (DPn = 20) on each arm. Droplets of these gel precursors were formed via a microfluidic organic-in-oil-in-water system where microparticles self-assembled via stereocomplexation and were stabilized after precipitation in deionized water. By varying the flow rate of the dispersed phase, well-defined microparticles with diameters of 33.7 ± 0.5, 62.4 ± 0.6, and 105.7 ± 0.8 µm were fabricated. Gelation due to stereocomplexation was confirmed via wide-angle X-ray scattering in which HMPs exhibited the signature diffraction pattern of stereocomplexed PLA at 2θ = 12.2, 21.2, 24.2°. Differential scanning calorimetry also confirmed stereocomplexation by the appearance of a crystallization exotherm (Tc = 37 °C) and a high-temperature endotherm (Tm = 159 °C) that does not appear in the homocrystallization of PLLA or the hydrogel precursors. Additionally, the propargyl handle present on the cross-linker allows for pre- or post-assembly thiol-yne "click" functionalization as demonstrated by the addition of thiol-containing fluorophores to the HMPs.

Acoustofluidic Droplet Sorter Based on Single Phase Focused Transducers.

Droplet microfluidics has revolutionized the biomedical and drug development fields by allowing for independent microenvironments to conduct drug screening at the single cell level. However, current microfluidic sorting devices suffer from drawbacks such as high voltage requirements (e.g., >200 Vpp), low biocompatibility, and/or low throughput. In this article, a single-phase focused transducer (SPFT)-based acoustofluidic chip is introduced, which outperforms many microfluidic droplet sorting devices through high energy transmission efficiency, high accuracy, and high biocompatibility. The SPFT-based sorter can be driven with an input power lower than 20 Vpp and maintain a postsorting cell viability of 93.5%. The SPFT sorter can achieve a throughput over 1000 events per second and a sorting purity up to 99.2%. The SPFT sorter is utilized here for the screening of doxorubicin cytotoxicity on cancer and noncancer cells, proving its drug screening capability. Overall, the SPFT droplet sorting device shows great potential for fast, precise, and biocompatible drug screening.

Analyzing the impact of fintech industry and green financing on energy poverty in the European countries.

In the fourth industrial revolution, the fintech has significantly expanded during the last several years, and this has caused scholars to worry about how much electricity is being used. Because energy poverty is one of the most critical social policy concerns facing the majority of nations in the world in the modern era. This study adds to what has already been written by looking at how the fintech industry affects the environment and energy in European countries. The current study investigates how the growing awareness of the need to preserve energy and the environment has an effect on society, and analyzes the role of the fintech industry, green finance, energy efficiency, and research and development on energy poverty across European nations from 2013 to 2020. To estimate long- and short-term impacts, DOLS and FMOLS are used along with diagnostic tests. The outcomes found that there is a tight relationship between energy poverty and all the factors taken into consideration (fintech, green finance, energy efficiency, and R&D). EU governments should employ "green finance" to encourage and enable the fintech industry since fintech plays a vital role in enhancing environmental effectiveness. The financing of environmentally friendly projects is very beneficial and might help alleviate energy poverty. The findings also indicate that more financing, ecological subsidies, and social assistance programs are necessary in order to satisfy the needs for energy and put an end to energy poverty in Europe. Policymakers in the tech world may be especially interested in the results.

Advances in Microsphere-based Super-resolution Imaging.

Techniques to resolve images beyond the diffraction limit of light with a large field of view (FOV) are necessary to foster progress in various fields such as cell and molecular biology, biophysics, and nanotechnology, where nanoscale resolution is crucial for understanding the intricate details of large-scale molecular interactions. Although several means of achieving super-resolutions exist, they are often hindered by factors such as high costs, significant complexity, lengthy processing times, and the classical tradeoff between image resolution and FOV. Microsphere-based super-resolution imaging has emerged as a promising approach to address these limitations. In this review, we delve into the theoretical underpinnings of microsphere-based imaging and the associated photonic nanojet. This is followed by a comprehensive exploration of various microsphere-based imaging techniques, encompassing static imaging, mechanical scanning, optical scanning, and acoustofluidic scanning methodologies. This review concludes with a forward-looking perspective on the potential applications and future scientific directions of this innovative technology.

High-yield and rapid isolation of extracellular vesicles by flocculation via orbital acoustic trapping: FLOAT.

Extracellular vesicles (EVs) have been identified as promising biomarkers for the noninvasive diagnosis of various diseases. However, challenges in separating EVs from soluble proteins have resulted in variable EV recovery rates and low purities. Here, we report a high-yield ( > 90%) and rapid ( < 10 min) EV isolation method called FLocculation via Orbital Acoustic Trapping (FLOAT). The FLOAT approach utilizes an acoustofluidic droplet centrifuge to rotate and controllably heat liquid droplets. By adding a thermoresponsive polymer flocculant, nanoparticles as small as 20 nm can be rapidly and selectively concentrated at the center of the droplet. We demonstrate the ability of FLOAT to separate urinary EVs from the highly abundant Tamm-Horsfall protein, addressing a significant obstacle in the development of EV-based liquid biopsies. Due to its high-yield nature, FLOAT reduces biofluid starting volume requirements by a factor of 100 (from 20 mL to 200 µL), demonstrating its promising potential in point-of-care diagnostics.

Aerosol jet printing of surface acoustic wave microfluidic devices.

The addition of surface acoustic wave (SAW) technologies to microfluidics has greatly advanced lab-on-a-chip applications due to their unique and powerful attributes, including high-precision manipulation, versatility, integrability, biocompatibility, contactless nature, and rapid actuation. However, the development of SAW microfluidic devices is limited by complex and time-consuming micro/nanofabrication techniques and access to cleanroom facilities for multistep photolithography and vacuum-based processing. To simplify the fabrication of SAW microfluidic devices with customizable dimensions and functions, we utilized the additive manufacturing technique of aerosol jet printing. We successfully fabricated customized SAW microfluidic devices of varying materials, including silver nanowires, graphene, and poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS). To characterize and compare the acoustic actuation performance of these aerosol jet printed SAW microfluidic devices with their cleanroom-fabricated counterparts, the wave displacements and resonant frequencies of the different fabricated devices were directly measured through scanning laser Doppler vibrometry. Finally, to exhibit the capability of the aerosol jet printed devices for lab-on-a-chip applications, we successfully conducted acoustic streaming and particle concentration experiments. Overall, we demonstrated a novel solution-based, direct-write, single-step, cleanroom-free additive manufacturing technique to rapidly develop SAW microfluidic devices that shows viability for applications in the fields of biology, chemistry, engineering, and medicine.

How environmental protection activities and industrial revolution contributes in the nexus of energy security and environmental sustainability?

The booming fintech industry seeks to revolutionize traditional financial practices, introducing new business models and innovative applications to enhance financial services. However, the widespread adoption of fintech may lead to increased energy consumption, posing environmental challenges. Comprehensive research is essential to understand the impact of fintech on economies, financial culture, and the environment, facilitating informed decision-making to foster sustainable growth in the sector. Therefore, the present research will explore how the fintech industry, green finance, and energy efficiency play their role in energy security and the achievement of a sustainable environment. The current study used data from 2000 to 2020 by employing Fourier autoregressive distributed lag (ARDL), fully modified least squares (FMOLS), and dynamic ordinary least squares (DOLS) econometric techniques to explore how the industrial revolution, environmental protection activities, and energy efficiency affect energy security and the environment across European countries. According to the findings, the fintech sector encourages the use of eco-friendly and energy-efficient technology, which assists in lowering carbon emissions and boosting energy security and efficiency. The outcomes of energy efficiency show a negative relationship with carbon emissions but a considerably positive relationship with energy security. This research shows that green financing has a favorable influence on energy security, and in European nations, green financing drives the majority of investments made for environmental conservation.

Income inequality, economic growth, renewable energy usage, and environmental degradation in the Belt and Road initiative countries: dynamic panel estimation.

This study investigates the effect of income inequality, carbon dioxide emissions, renewable energy consumption, and economic growth on each other's in the Belt and Road initiative countries from 2002 to 2019. By using OLS, fixed effect, difference GMM, system GMM, and seemingly unrelated regression (SUR) models, the results show that income inequality and renewable energy consumption are reduced while economic growth, foreign direct investment, and financial development have an increasing effect on carbon emissions. The effect of carbon emissions and renewable energy consumption is negative, while economic growth is positive and negative for income inequality across different models. Income inequality, carbon dioxide emissions, economic growth, and foreign direct investment are negatives for renewable energy consumption. Income inequality is positive, while carbon dioxide and financial development negatively affect economic growth. The findings have considerable policy implications for the sample countries regarding income distribution, energy use, environmental quality, and enhancing economic growth. The countries should focus on acquiring renewable energy sources to increase economic growth and reduce environmental pollution.

Acoustic tweezers for high-throughput single-cell analysis.

Acoustic tweezers provide an effective means for manipulating single cells and particles in a high-throughput, precise, selective and contact-free manner. The adoption of acoustic tweezers in next-generation cellular assays may advance our understanding of biological systems. Here we present a comprehensive set of instructions that guide users through device fabrication, instrumentation setup and data acquisition to study single cells with an experimental throughput that surpasses traditional methods, such as atomic force microscopy and micropipette aspiration, by several orders of magnitude. With acoustic tweezers, users can conduct versatile experiments that require the trapping, patterning, pairing and separation of single cells in a myriad of applications ranging across the biological and biomedical sciences. This procedure is widely generalizable and adaptable for investigations in materials and physical sciences, such as the spinning motion of colloids or the development of acoustic-based quantum simulations. Overall, the device fabrication requires ~12 h, the experimental setup of the acoustic tweezers requires 1-2 h and the cell manipulation experiment requires ~30 min to complete. Our protocol is suitable for use by interdisciplinary researchers in biology, medicine, engineering and physics.

Acoustofluidic Interfaces for the Mechanobiological Secretome of MSCs.

While mesenchymal stem cells (MSCs) have gained enormous attention due to their unique properties of self-renewal, colony formation, and differentiation potential, the MSC secretome has become attractive due to its roles in immunomodulation, anti-inflammatory activity, angiogenesis, and anti-apoptosis. However, the precise stimulation and efficient production of the MSC secretome for therapeutic applications are challenging problems to solve. Here, we report on Acoustofluidic Interfaces for the Mechanobiological Secretome of MSCs: AIMS. We create an acoustofluidic mechanobiological environment to form reproducible three-dimensional MSC aggregates, which produce the MSC secretome with high efficiency. We confirm the increased MSC secretome is due to improved cell-cell interactions using AIMS: the key mediator N-cadherin was up-regulated while functional blocking of N-cadherin resulted in no enhancement of the secretome. After being primed by IFN-γ, the secretome profile of the MSC aggregates contains more anti-inflammatory cytokines and can be used to inhibit the pro-inflammatory response of M1 phenotype macrophages, suppress T cell activation, and support B cell functions. As such, the MSC secretome can be modified for personalized secretome-based therapies. AIMS acts as a powerful tool for improving the MSC secretome and precisely tuning the secretory profile to develop new treatments in translational medicine.

Cellular immunity analysis by a modular acoustofluidic platform: CIAMAP.

The study of molecular mechanisms at the single-cell level holds immense potential for enhancing immunotherapy and understanding neuroinflammation and neurodegenerative diseases by identifying previously concealed pathways within a diverse range of paired cells. However, existing single-cell pairing platforms have limitations in low pairing efficiency, complex manual operation procedures, and single-use functionality. Here, we report a multiparametric cellular immunity analysis by a modular acoustofluidic platform: CIAMAP. This platform enables users to efficiently sort and collect effector-target (i.e., NK92-K562) cell pairs and monitor the real-time dynamics of immunological response formation. Furthermore, we conducted transcriptional and protein expression analyses to evaluate the pathways that mediate effector cytotoxicity toward target cells, as well as the synergistic effect of doxorubicin on the cellular immune response. Our CIAMAP can provide promising building blocks for high-throughput quantitative single-cell level coculture to understand intercellular communication while also empowering immunotherapy by precision analysis of immunological synapses.

Nexus between disaggregated energy sources, institutional quality, and environmental degradation in BRI countries: a penal quantile regression analysis.

The present study aims to contribute to the existing literature by examining the role of institutional quality in the nexus of disaggregated energy sources and environmental degradation for belt and road initiative countries. To empirically support the theoretically presented propositions, a series of analytical techniques are used, such as LLC, IPS for unit root, Johansen-Fisher panel co-integration to check the long-run association between the considered variables from 2000 to 2020. Further, a panel quantile regression and panel fixed effect model is used in the study to explore the nexus. The study found a long-run association between institutional quality (IQ), energy production from oil (EPOil), natural gas (EPGas), coal (EPCoal), renewables (EPRenew), and CO2 emission in BRI countries. According to panel unit-root tests, all variables are integrated of order I(1), and the panel co-integration test showed a log-run association among variables. The results of panel quantile regression and panel fixed effect model showed a positive association between IQ and CO2 emission. Similarly, an association of CO2 emission with EPGas, EPOil, and EPCoal is also significantly positive. The extraction and use of fossil fuels (natural gas, oil, and coal) pollute the air, while, on the other hand, there is a negative relationship found between CO2 emission and EPRenew. When developing environmental protection measures, governments should choose to concentrate on the quality of institutions. The effectiveness of institutions in BRI countries will provide appropriate rules, regulations, property rights, and methods to fight corruption, which, if followed systematically, would decrease CO2 emissions and enhance the quality of the environment in BRI countries.

Striving towards sustainable development: how environmental degradation and energy efficiency interact with health expenditures in SAARC countries.

The previous studies focused on environmental issues, identifying their root causes, urging prompt action to reduce environmental degradation. In this context, the current article extends the literature by incorporating the ecological impacts on the health sector and the role of sustainable development. The present study adds to the body of knowledge by examining the relationship between CO2 emissions, sustainable development, energy efficiency, energy intensity, and health expenditures for SAARC countries from 2000 to 2020. Fully modified OLS (FMOLS) and dynamic OLS (DOLS) are used and diagnostic tests to check the association between the variables. The empirical analysis validated the long-run impact of the examined factors on health expenditures. The results show that energy efficiency and sustainable development have a statistically significant negative effect on health expenditures, vice-versa for CO2 emission. Energy efficiency, energy intensity, and CO2 emissions have been shown to have a one-way causative relationship with health expenditures, but sustainable development and economic growth have a two-way causation relationship. The better health status of the SAARC economies necessitates the establishment of long-term development strategies, environmental sustainability, and an examination of the energy sector. This work's conceptual and empirical advances have significant policy ramifications for this part of the globe and its efforts to improve sustainability.

A sound approach to advancing healthcare systems: the future of biomedical acoustics.

Newly developed acoustic technologies are playing a transformational role in life science and biomedical applications ranging from the activation and inactivation of mechanosensitive ion channels for fundamental physiological processes to the development of contact-free, precise biofabrication protocols for tissue engineering and large-scale manufacturing of organoids. Here, we provide our perspective on the development of future acoustic technologies and their promise in addressing critical challenges in biomedicine.

Fiber Optic-Based Thermal Integrity Profiling of Drilled Shaft: Inverse Modeling for Spiral Fiber Deployment Strategy.

The current state of practice to interpret the thermal integrity profiling (TIP) data of drilled shaft is the so-called effective radius method. It uses the concrete pouring log and average temperature to construct a relationship between temperature distribution and effective radius that can be used to reconstruct a drilled shaft model. While this effective radius method is computationally inexpensive and has good operationality, it is not good at predicting the dimensions and shape of shaft defects. Upgrading the sensor used in conventional TIP from thermocouples/thermal wires to fiber optic sensors, the spatial resolution of the measured temperature will be enhanced. By using the newly proposed spiral fiber deployment strategy, we can improve the reconstruction of shaft defects in the integrity testing of drilled shafts. The corresponding inverse modeling of defected shaft reconstruction for spiral deployment is proposed in this paper based on the temperature distribution pattern that is learned from forward modeling. Through inverse modeling, the details of defects in drilled shafts can be reconstructed numerically. An analysis of the results shows that the prediction by inverse modeling has good agreement with the forward modeling set up initially. This work helps the evolution of the TIP from the nondestructive testing stage to the quantitative nondestructive evaluation stage.

Geopolitical risks, energy consumption, and CO2 emissions in BRICS: an asymmetric analysis.

Environmental pollution is a geopolitical problem, and researchers have not considered it seriously yet. This study examines the asymmetric influence of geopolitical risk on energy consumption and CO2 emissions in BRICS economies using the non-linear autoregressive distributed lag model (NARDL) testing method over the period of 1985-2019. Therefore, we observed that in the long run, a positive and negative change in geopolitical risk has negative effect on energy consumption in India, Brazil, and China. The outcomes confirmed that an increase in geopolitical risk has negative effect on CO2 emissions in Russia and South Africa. Although a decrease in geopolitical risk has negative effects on CO2 emissions in India, China, South Africa, it has positive coefficient in Russia in the long run. Based on empirical findings, we also revealed that asymmetries mostly exist in terms of magnitude rather than direction. Our empirical results are country and group specific. The findings call for important changes in energy and environment policies to accommodate geopolitical risks.

Low-carbon pathways for the booming express delivery sector in China.

Express delivery services are booming in both developed and emerging economies due to their low cost, convenience, and the fast growth in online shopping. The increasing environmental impacts of express delivery services and mitigation potentials, however, remain largely unexplored. Here we addressed such a gap for China, a country which is expanding online retail sales and express delivery rapidly. We found a total of 8.8 Mt of scrap packaging materials were generated by the express delivery sector in China in 2018. Its transportation-related GHG emissions surged from 0.3 Mt in 2007 to 13.7 Mt of CO2-equivalent (CO2e) in 2018, with an average of 0.27 kgCO2e per piece. Over 80% from online shopping deliveries. We predict these emissions will reach 75 MtCO2e by 2035. Nevertheless, it is possible to mitigate such GHG emissions by 102~134 MtCO2e between 2020 and 2035 if a suite of policies is adopted, including a slowdown of delivery speed, fuel system upgrades, packaging materials reduction, logistics optimization, and carbon pricing.

A microfluidic approach for experimentally modelling the intercellular coupling system of a mammalian circadian clock at single-cell level.

In mammals, it is believed that the intercellular coupling mechanism between neurons in the suprachiasmatic nucleus (SCN) confers robustness and distinguishes the central clock from peripheral circadian oscillators. Current in vitro culturing methods used in Petri dishes to study intercellular coupling by exogenous factors invariably cause perturbations, such as simple media changes. Here, we design a microfluidic device to quantitatively study the intercellular coupling mechanism of circadian clock at the single cell level, and demonstrate that vasoactive intestinal peptide (VIP) induced coupling in clock mutant Cry1-/- mouse adult fibroblasts engineered to express the VIP receptor, VPAC2, is sufficient to synchronize and maintain robust circadian oscillations. Our study provides a proof-of-concept platform to reconstitute the intercellular coupling system of the central clock using uncoupled, single fibroblast cells in vitro, to mimic SCN slice cultures ex vivo and mouse behavior in vivo phenotypically. Such a versatile microfluidic platform may greatly facilitate the studies of intercellular regulation networks, and provide new insights into the coupling mechanisms of the circadian clock.

Microfluidic Isolation and Enrichment of Nanoparticles.

Over the past decades, nanoparticles have increased in implementation to a variety of applications ranging from high-efficiency electronics to targeted drug delivery. Recently, microfluidic techniques have become an important tool to isolate and enrich populations of nanoparticles with uniform properties (e.g., size, shape, charge) due to their precision, versatility, and scalability. However, due to the large number of microfluidic techniques available, it can be challenging to identify the most suitable approach for isolating or enriching a nanoparticle of interest. In this review article, we survey microfluidic methods for nanoparticle isolation and enrichment based on their underlying mechanisms, including acoustofluidics, dielectrophoresis, filtration, deterministic lateral displacement, inertial microfluidics, optofluidics, electrophoresis, and affinity-based methods. We discuss the principles, applications, advantages, and limitations of each method. We also provide comparisons with bulk methods, perspectives for future developments and commercialization, and next-generation applications in chemistry, biology, and medicine.

Correction: Acoustic tweezers based on circular, slanted-finger interdigital transducers for dynamic manipulation of micro-objects.

Correction for 'Acoustic tweezers based on circular, slanted-finger interdigital transducers for dynamic manipulation of micro-objects' by Putong Kang et al., Lab Chip, 2020, 20, 987-994, DOI: .