Manipulation Of Cells Research Articles

Generation of helical multi-functional microfiber motors based on modified microfluidic spinning method

Due to unique asymmetric shapes and easily realized directional movements, helical micromotors are widely used in applications such as drug delivery, cell manipulation, and wastewater purification. However, most of the hydrogel helical microfiber motors were water-based and had a homogeneous polymer network structure, which limited their practical applications like drug release. In this study, an emulsion-based microfluidic spinning method was used to prepare heterogenous helical hydrogel microfiber motors. Fine oil-in-water (O/W) emulsions were used as the inner phase of the microfluidic spinning process. When dichloromethane was used, micromotors with porous structure were formed after solidification and volatilization, improving the catalytic degradation rate of pollutants in water treatment application. When soybean oil was used, fat-soluble drugs were encapsulated successfully and gradually released as the micromotor degraded. Besides, the diameter and pitch size of the prepared fibers could be easily adjusted, and mass manufacturing (>100 m) was achieved.

Molecular mechanisms of the stress-induced regulation of the inflammatory response in fish

Stressors in the environment of aquatic organisms can profoundly affect their immune system. The stress response in fish involves the activation of the hypothalamus-pituitary-interrenal (HPI) axis, leading to the release of several stress hormones, among them glucocorticoids, such as cortisol, which bind and activate corticosteroid receptors, namely the glucocorticoid receptor (GR) and mineralocorticoid receptor (MR). These receptors are highly expressed on immune cells, thereby allowing stress to have a potent effect that is classically considered to suppress immune function. In this review, we highlight the conserved structure and function of GR and MR among vertebrates and describe their role in modulating inflammation by regulating the expression of pro-inflammatory and anti-inflammatory genes. In particular, the involvement of MR during inflammation is reviewed, which in many studies has been shown to be immune-enhancing. In recent years, the use of zebrafish as a model organism has opened up new possibilities to study the effects of stress on inflammation, making it possible to investigate knockout lines for MR and/or GR, in combination with transgenic models with fluorescently labeled leukocyte subpopulations that enable the visualization and manipulation of these immune cells. The potential roles of other hormones of the HPI axis, such as corticotrophin-releasing hormone (Crh) and adrenocorticotropic hormone (Acth), in immune modulation are also discussed. Overall, this review highlights the need for further research to elucidate the specific roles of GR, MR and other stress hormones in regulating immune function in fish. Understanding these mechanisms will contribute to improving fish health and advancing our knowledge of stress signalling.

Deciphering viscoelastic cell manipulation in rectangular microchannels.

Viscoelastic focusing has emerged as a promising method for label-free and passive manipulation of micro and nanoscale bioparticles. However, the design of microfluidic devices for viscoelastic particle focusing requires a thorough comprehensive understanding of the flow condition and operational parameters that lead to the desired behavior of microparticles. While recent advancements have been made, viscoelastic focusing is not fully understood, particularly in straight microchannels with rectangular cross sections. In this work, we delve into inertial, elastic, and viscoelastic focusing of biological cells in rectangular cross-section microchannels. By systematically varying degrees of fluid elasticity and inertia, we investigate the underlying mechanisms behind cell focusing. Our approach involves injecting cells into devices with a fixed, non-unity aspect ratio and capturing their images from two orientations, enabling the extrapolation of cross-sectional equilibrium positions from two dimensional (2D) projections. We characterized the changes in hydrodynamic focusing behaviors of cells based on factors, such as cell size, flow rate, and fluid characteristics. These findings provide insights into the flow characteristics driving changes in equilibrium positions. Furthermore, they indicate that viscoelastic focusing can enhance the detection accuracy in flow cytometry and the sorting resolution for size-based particle sorting applications. By contributing to the advancement of understanding viscoelastic focusing in rectangular microchannels, this work provides valuable insight and design guidelines for the development of devices that harness viscoelastic focusing. The knowledge gained from this study can aid in the advancement of viscoelastic particle manipulation technique and their application in various fields.

High-efficiency inertial focusing based on enhanced secondary flow generated by ring-inner obstacle combined channels

Inertial-focusing microfluidics enables extensive applications such as particle manipulation, single-cell analysis, and flow cytometry due to its various advantages, including high throughput, simplicity of devices, ease of operation, and freedom from external fields. Generally, only one type of secondary flow, such as Dean or geometry-induced secondary flow, is used in inertial focusing, leading to a low focusing efficiency. Combining channels with two or more geometries can enhance the secondary flows and thus improve the focusing performance. This study investigated the inertial focusing mechanism of a combination of four channel types. First, we constructed an annular channel, a contraction-expansion array channel, and an annular channel with obstacles distributed along the inner and outer walls. Then, theoretical modeling and focusing experiments for the four channels were carried out using four kinds of fluorescent particles as well as breast cancer cells. The results demonstrated that the annular channel combined with obstacles along the inner wall (ring-inner obstacle combined channel) generated an enhanced secondary flow and exhibited a particle-focusing efficiency of > 99% and a cell-focusing efficiency of > 95%. Furthermore, we summarized the design considerations of the combined channels for promoting cell focusing and separation. The inertial focusing devices with combined channels could offer an efficient means for continuous cell manipulation, high-throughput cytometry, and high-precision single-cell analysis.

A Versatile Strategy for Genetic Manipulation of Cajal-Retzius Cells in the Adult Mouse Hippocampus.

Cajal-Retzius (CR) cells are transient neurons with long-lasting effects on the architecture and circuitry of the neocortex and hippocampus. Contrary to the prevailing assumption that CR cells completely disappear in rodents shortly after birth, a substantial portion of these cells persist in the hippocampus throughout adulthood. The role of these surviving CR cells in the adult hippocampus is largely unknown, partly because of the paucity of suitable tools to dissect their functions in the adult versus the embryonic brain. Here, we show that genetic crosses of the ΔNp73-Cre mouse line, widely used to target CR cells, to reporter mice induce reporter expression not only in CR cells, but also progressively in postnatal dentate gyrus granule neurons. Such a lack of specificity may confound studies of CR cell function in the adult hippocampus. To overcome this, we devise a method that not only leverages the temporary CR cell-targeting specificity of the ΔNp73-Cre mice before the first postnatal week, but also capitalizes on the simplicity and effectiveness of freehand neonatal intracerebroventricular injection of adeno-associated virus. We achieve robust Cre-mediated recombination that remains largely restricted to hippocampal CR cells from early postnatal age to adulthood. We further demonstrate the utility of this method to manipulate neuronal activity of CR cells in the adult hippocampus. This versatile and scalable strategy will facilitate experiments of CR cell-specific gene knockdown and/or overexpression, lineage tracing, and neural activity modulation in the postnatal and adult brain.

A review of magnetically driven swimming microrobots: Material selection, structure design, control method, and applications

Abstract Magnetically driven swimming microrobot is a typical one in the family of microrobots and they can achieve navigation and manipulation in low Reynolds number biomedical environments with an external magnetic drive strategy. This study reviews recent advances in material selection, structure design, fabrication techniques, drive control method, and applications for magnetically driven swimming microrobots. First, the materials used in magnetically driven swimming microrobots were introduced and the effect of material selection on performance was discussed. Second, structure design of swimming microrobots and manufacturing techniques are reviewed, followed by a discussion on the main advances in effective motion control, path planning, and path tracking. Then, the multi-applications of magnetically driven swimming microrobots including targeted drug delivery, cell manipulation, and minimally invasive surgery are summarized. Finally, the current challenges and future directions of the work on magnetically driven swimming microrobots are discussed.

Single neurons on microelectrode array chip: manipulation and analyses.

Chips-based platforms intended for single-cell manipulation are considered powerful tools to analyze intercellular interactions and cellular functions. Although the conventional cell co-culture models could investigate cell communication to some extent, the role of a single cell requires further analysis. In this study, a precise intercellular interaction model was built using a microelectrode array [microelectrode array (MEA)]-based and dielectrophoresis-driven single-cell manipulation chip. The integrated platform enabled precise manipulation of single cells, which were either trapped on or transferred between electrodes. Each electrode was controlled independently to record the corresponding cellular electrophysiology. Multiple parameters were explored to investigate their effects on cell manipulation including the diameter and depth of microwells, the geometry of cells, and the voltage amplitude of the control signal. Under the optimized microenvironment, the chip was further evaluated using 293T and neural cells to investigate the influence of electric field on cells. An examination of the inappropriate use of electric fields on cells revealed the occurrence of oncosis. In the end of the study, electrophysiology of single neurons and network of neurons, both differentiated from human induced pluripotent stem cells (iPSC), was recorded and compared to demonstrate the functionality of the chip. The obtained preliminary results extended the nature growing model to the controllable level, satisfying the expectation of introducing more elaborated intercellular interaction models.

Novel Strategy Toward Light Absorption Enhancement of Organic Solar Cells Using M13 Bacteriophage

In organic photovoltaics (OPVs), the development of efficient light‐harvesting organic donor and acceptor materials and the design of a device structure with appropriate visible light transmittance play an important role in increasing their power conversion efficiency. Light manipulation strategies in OPV are widely used to improve photovoltaic performance. One of the most popular technologies is antireflective coating (ARC), which enhances light utilization in devices. However, ARC has been investigated less in OPV cells than in organic silicon solar cells. Herein, a novel approach that employs the natural biomaterial M13 bacteriophage (M13) as an intermediate layer with a thickness of a few nanometers between the hole transport layer (HTL) and indium tin oxide is investigated. The functional surface hydrophilicity, obtained by genetic manipulation of M13, improves the light transmittance by more than 84% over the visible wavelength range of the OPV cells. Furthermore, it enhances the coherence between the HTL and the photoactive layer. Therefore, the photocurrent density and power conversion efficiency significantly increase, producing a high photovoltaic performance. The proposed approach of using natural biomaterials is the basis for a novel, low‐cost, and eco‐friendly design for light manipulation in solar cells.

Three-dimensional cell culture of chimeric antigen receptor T cells originated from peripheral blood mononuclear cells towards cellular therapies

Background aimsWith the objective of improving the ex vivo production of therapeutic chimeric antigen receptor (CAR) T cells, we explored the addition of three-dimensional (3D) polystyrene scaffolds to standard suspension cell cultures. MethodsWe aimed to mimic the structural support given by the lymph nodes during in vivo lymphocyte expansion. ResultsWe observed an increase in cell proliferation compared with standard suspension systems as well as an enhanced cytotoxicity toward cancer cells. Moreover, we directly obtained the CAR T cells from peripheral blood mononuclear cells, thus minimizing the ex vivo manipulation of the therapeutic cells and opening the way to synergies among different cell populations. ConclusionsWe propose the use of commercially available 3D polystyrene systems to improve the current immune cell cultures and resulting cell products for emerging cellular (immuno)therapies.

Programming an Enhanced Uptake and the Intracellular Fate of Magnetic Microbeads.

This study compares two kinds of magnetic microbeads with different surface features and cell entry pathways, aiming to provide insights into how to program their cell uptake and intracellular fate. It is found that a rougher surface enhances the cell uptake of the microbeads, regardless of whether they are pulled by a magnetic field gradient or adsorbed by the cell membrane. However, the entry route affects the intracellular localization of the microbeads: The magnetically dragged microbeads reach the cytoplasm, while the adsorbed microbeads stay in the late endosomes and lysosomes. This suggests that different strategies can be used to target different cellular compartments with magnetic microbeads. Moreover, it is demonstrated that the cells containing the microbeads can be moved and regrown at specific locations by applying a magnetic field gradient, showing the potential of these magnetic microbeads for cell delivery and manipulation.

Elliptic perfect vortex beam generation with selective modes based on single layer metasurface in broadband near-infrared range

Asymmetric and multiple modes of perfect vortex beams (PVBs) are of great significance in the manipulation of nanoscale biological cells. As a powerful artificial subwavelength platform, miscellaneous metasurfaces have been reported to generate PVBs. However, these reported PVBs are always symmetric, that is, only one simple annular shape in the observation plane, which cannot provide multiple modes. Here, using multi-coordinate transformation techniques (MCTT), we established the phase profile of mode-selective elliptic perfect vortex beams (MS-EPVBs) in elliptical coordinate and generated multiple modes of EPVBs with arbitrary eccentricity and orientation in broadband near-infrared range based on all-dielectric metasurface, greatly enriching the modes of PVBs. Composed of optimized half-waveplate-like silicon cylinders, the designed metasurface can freely transform the incident light into EPVBs with arbitrary eccentricity and orientation with high efficiency. Furthermore, during the mode transformation, the properties of the “perfect” and broadband were preserved. This work will find potential applications in advanced fields like biophotonics and genetic engineering.

Design and testing of a new microinjector with FBG force sensor for robot-assisted single cell microinjection

Microinjection with force sensing has demonstrated robust performance in improving the cell survival rate and adjusting robot motion parameters. In this article, a novel force-sensing microinjector is presented based on fiber Bragg grating (FBG) sensors to precept three-dimensional (3D) forces. Fibers are processed with acid to become thinner and more sensitive. Three optical fibers are affixed to the outer surface of the glass needle along the axial direction. Benefiting from the novel configuration of the FBG sensors, the hollow channel of the glass needle can be used to inject exogenous substances. Moreover, a prototype has been fabricated for the experiment. Experimental results demonstrate the proposed force sensor can achieve a resolution of 66.8 μN for puncture forces. Repeatability and temperature compensation experiments show the force sensor can provide a consistent and accurate measurement. The developed force sensor has been applied to the microinjection of the zebrafish embryos, which is a promising tool for perceiving cell manipulation microforces.

Pericellular Matrix Formation and Atomic Force Microscopy of Single Primary Human Chondrocytes Cultured in Alginate Microgels.

One of the main components of articular cartilage is the chondrocyte's pericellular matrix (PCM), which is critical for regulating mechanotransduction, biochemical cues, and healthy cartilage development. Here, individual primary human chondrocytes (PHC) are encapsulated and cultured in 50µm diameter alginate microgels using drop-based microfluidics. This unique culturing method enables PCM formation and manipulation of individual cells. Over ten days, matrix formation is observed using autofluorescence imaging, and the elastic moduli of isolated cells are measured using AFM. Matrix production and elastic modulus increase are observed for the chondrons cultured in microgels. Furthermore, the elastic modulus of cells grown in microgels increases ≈ten-fold over ten days, nearly reaching the elastic modulus of in vivo PCM. The AFM data is further analyzed using a Gaussian mixture model and shows that the population of PHCs grown in microgels exhibit two distinct populations with elastic moduli averaging 9.0and 38.0kPa. Overall, this work shows that microgels provide an excellent culture platform for the growth and isolation of PHCs, enabling PCM formation that is mechanically similar to native PCM. The microgel culture platform presented here has the potential to revolutionize cartilage regeneration procedures through the inclusion of in vitro developed PCM.

Magnetic force-based cell manipulation for in vitro tissue engineering.

Cell manipulation techniques such as those based on three-dimensional (3D) bioprinting and microfluidic systems have recently been developed to reconstruct complex 3D tissue structures in vitro. Compared to these technologies, magnetic force-based cell manipulation is a simpler, scaffold- and label-free method that minimally affects cell viability and can rapidly manipulate cells into 3D tissue constructs. As such, there is increasing interest in leveraging this technology for cell assembly in tissue engineering. Cell manipulation using magnetic forces primarily involves two key approaches. The first method, positive magnetophoresis, uses magnetic nanoparticles (MNPs) which are either attached to the cell surface or integrated within the cell. These MNPs enable the deliberate positioning of cells into designated configurations when an external magnetic field is applied. The second method, known as negative magnetophoresis, manipulates diamagnetic entities, such as cells, in a paramagnetic environment using an external magnetic field. Unlike the first method, this technique does not require the use of MNPs for cell manipulation. Instead, it leverages the magnetic field and the motion of paramagnetic agents like paramagnetic salts (Gadobutrol, MnCl2, etc.) to propel cells toward the field minimum, resulting in the assembly of cells into the desired geometrical arrangement. In this Review, we will first describe the major approaches used to assemble cells in vitro-3D bioprinting and microfluidics-based platforms-and then discuss the use of magnetic forces for cell manipulation. Finally, we will highlight recent research in which these magnetic force-based approaches have been applied and outline challenges to mature this technology for in vitro tissue engineering.

Cancer Immunotherapy Using Bioengineered Micro/Nano Structured Hydrogels.

Hydrogels, a class of materials with a 3Dnetwork structure, are widely used in various applications of therapeutic delivery, particularly cancer therapy. Micro and nanogels as miniaturized structures of the bioengineered hydrogels may provide extensive benefits over the common hydrogels in encapsulation and controlled release of small molecular drugs, macromolecular therapeutics, and even cells. Cancer immunotherapy is rapidly developing, and micro/nanostructured hydrogels have gained wide attention regarding their engineered payload release properties that enhance systemic anticancer immunity. Additionally, they are a great candidate due to their local administration properties with a focus on local immune cell manipulation in favor of active and passive immunotherapies. Although applied locally, such micro/nanostructured can also activate systemic antitumor immune responses by releasing nanovaccines safely and effectively inhibiting tumor metastasis and recurrence. However, such hydrogels are mostly used as locally administered carriers to stimulate the immune cells by releasing tumor lysate, drugs, or nanovaccines. In this review, the latest developments in cancer immunotherapy are summarized using micro/nanostructured hydrogels with a particular emphasis on their function depending on the administration route. Moreover, the potential for clinical translation of these hydrogel-based cancer immunotherapies is also discussed.

Immune-Cell-Mediated Cancer Treatment: Advantages, Drawbacks And Future Direction

Cancer ranks as the most lethal and prevalent non-communicable disease in clinical settings. Therapeutic options for cancer comprise chemotherapy, radiotherapy, surgery, and combined treatment. Cancer remission and relapse cases are widespread despite having various advanced medications and sophisticated dissection techniques. A new approach involving immune-cell-mediated cancer therapy has been adopted extensively for cancer treatments by utilizing immune cells. Immunotherapy has gained much attention to prevent and treat various types of cancer. Immunotherapy treatments operate in multiple contexts. Several immunotherapy therapeutic interventions assist the immune function in halting or reducing the advancement of cancer cells. Many also facilitate the immune cells in destroying cancerous cells or safeguarding against cancer from disseminating to certain other regions of the human body. Among other methods, genetic manipulation of immune cells offers hope for innovative anticancer treatment. T lymphocytes and natural killer cells have become the most extensively documented immune cells for immunotherapy. Chimeric antigen receptor T-cell therapy exhibits the most promising blood cancer treatment. However, adoptive NK cell transfer therapy displays potential anticancer treatment options, although more research is needed to be carried out. In addition, cytokine-induced immunomodulation is also plausible for cancer immunotherapy. This review will highlight the most comprehensive information, observations, and consequences associated with different cancer immunotherapy initiatives.

Four-Dimensional Micro/Nanorobots via Laser Photochemical Synthesis towards the Molecular Scale.

Miniaturized four-dimensional (4D) micro/nanorobots denote a forerunning technique associated with interdisciplinary applications, such as in embeddable labs-on-chip, metamaterials, tissue engineering, cell manipulation, and tiny robotics. With emerging smart interactive materials, static micro/nanoscale architectures have upgraded to the fourth dimension, evincing time-dependent shape/property mutation. Molecular-level 4D robotics promises complex sensing, self-adaption, transformation, and responsiveness to stimuli for highly valued functionalities. To precisely control 4D behaviors, current-laser-induced photochemical additive manufacturing, such as digital light projection, stereolithography, and two-photon polymerization, is pursuing high-freeform shape-reconfigurable capacities and high-resolution spatiotemporal programming strategies, which challenge multi-field sciences while offering new opportunities. Herein, this review summarizes the recent development of micro/nano 4D laser photochemical manufacturing, incorporating active materials and shape-programming strategies to provide an envisioning of these miniaturized 4D micro/nanorobots. A comparison with other chemical/physical fabricated micro/nanorobots further explains the advantages and potential usage of laser-synthesized micro/nanorobots.

Optimizing Bioink Composition for Human Chondrocyte Expression of Lubricin.

The surface zone of articular cartilage is the first area impacted by cartilage defects, commonly resulting in osteoarthritis. Chondrocytes in the surface zone of articular cartilage synthesize and secrete lubricin, a proteoglycan that functions as a lubricant protecting the deeper layers from shear stress. Notably, 3D bioprinting is a tissue engineering technique that uses cells encapsulated in biomaterials to fabricate 3D constructs. Gelatin methacrylate (GelMA) is a frequently used biomaterial for 3D bioprinting cartilage. Oxidized methacrylated alginate (OMA) is a chemically modified alginate designed for its tunable degradation rate and mechanical properties. To determine an optimal combination of GelMA and OMA for lubricin expression, we used our novel high-throughput human articular chondrocyte reporter system. Primary human chondrocytes were transduced with PRG4 (lubricin) promoter-driven Gaussia luciferase, allowing for temporal assessment of lubricin expression. A lubricin expression-driven Design of Experiment screen and subsequent validation identified 14% GelMA/2% OMA for further study. Therefore, DoE optimized 14% GelMA/2% OMA, 14% GelMA control, and 16% GelMA (total solid content control) were 3D bioprinted. The combination of lubricin protein expression and shape retention over the 22 days in culture, successfully determined the 14% GelMA/2%OMA to be the optimal formulation for lubricin secretion. This strategy allows for rapid analysis of the role(s) of biomaterial composition, stiffness or other cell manipulations on lubricin expression by chondrocytes, which may improve therapeutic strategies for cartilage regeneration.

Moving on: How malaria parasites exit the liver.

An essential step in the life cycle of malaria parasites is their egress from hepatocytes, which enables the transition from the asymptomatic liver stage to the pathogenic blood stage of infection. To exit the liver, Plasmodium parasites first disrupt the parasitophorous vacuole membrane that surrounds them during their intracellular replication. Subsequently, parasite-filled structures called merosomes emerge from the infected cell. Shrouded by host plasma membrane, like in a Trojan horse, parasites enter the vasculature undetected by the host immune system and travel to the lung where merosomes rupture, parasites are released, and the blood infection stage begins. This complex, multi-step process must be carefully orchestrated by the parasite and requires extensive manipulation of the infected host cell. This review aims to outline the known signaling pathways that trigger exit, highlight Plasmodium proteins that contribute to the release of liver-stage merozoites, and summarize the accompanying changes to the hepatic host cell.

In vivo optical trapping of erythrocytes in mouse liver imaged with oblique back-illumination microscopy

Optical tweezers are ideal tools for cell manipulation in vivo due to their non-contact trapping ability. In the current studies, the optical trapping of cells can only be achieved in light-permeable organs. It is important to expand the application of optical tweezers to opaque tissues and organs, where biological activities are the primary focus of biomedical research. However, the optical manipulation of cells in these opaque organs cannot be imaged using a conventional transillumination microscope due to the opacity of these organs. Here, we use optical tweezers to trap erythrocytes and measure the cell deformability in mouse liver, which are imaged with oblique back-illumination microscopy (OBM). In the microscope system, two fibers are fixed at the same oblique angle on both sides of the microscopic objective, illuminating the trapping target asymmetrically. The dual-wavelength OBM strategy allows for obtaining a differential phase contrast image in a single-shot by color channel separation. The OBM can image the flowing and trapped erythrocytes in vivo in real-time. Furthermore, the erythrocyte deformability in vivo is evaluated with optical tweezers. The spring stiffness in vivo is 8.2 ± 2.1 μN m−1, which is obtained by stretching the trapped cells with blood drag flow. Our works make it possible to utilize optical tweezers to study the live cell dynamics in opaque organs, which will expand the application of optical tweezers in the fields of biomechanical studies.