Cell Orientation Research Articles

Turn Your Half-Cut Cells for a Stronger Module

We employ an existing model of crystalline silicon photovoltaic module cell fracture to explore the effect of cell size and orientation on their probability of fracture under module uniform loading. In addition, we also apply continuum damage mechanics to modify this model to consider the effect of cell fracture on the probability of subsequent cell fracture. We elucidate that cell fracture increases the probability of subsequent cell fracture and that rectangular modules containing half-cells aligned with the module's long orientation are much more robust against cell fracture than full-cell and half-cell short orientation modules.

Geometrical Analysis of White Blood Cells by Using Image Segmentation Algorithm

Abstract: The technique behind image analysis is based on machine learning. In order for the software to recognize specific irregularities, it doesn't matter what field of medicine (or other industry) we're thinking about. The way AI learns differs dramatically from how humans learn. It makes use of enormous image databases that the software must interpret and analyze. In the present work, geometrical features of White Blood Cells such Area, Perimeter, Orientation, and Equivalent Diameter are calculated by using Image Segmentation approach.

Ontogeny of the inner ear maculae in school sharks (Galeorhinus galeus)

Studies on the auditory system of fishes can provide fundamental information about the early evolution of vertebrate hearing. While there are limited data available on the auditory system of bony fishes, comparatively far less is known about auditory structures in elasmobranchs, despite their critical basal position within vertebrate evolution. Specifically, while there is a high degree of plasticity in the nervous system, little is known about how the different sensory epithelia within the inner ear vary throughout life in elasmobranchs. Using a combination of immunohistochemistry and fluorescence microscopy, we quantified macular area, number of sensory hair cells, hair cell density, and hair cell orientations in the saccule, lagena, utricle, and macula neglecta of school sharks (Galeorhinus galeus) of varying body size. In all maculae, macular area and the number of hair cells increased significantly throughout ontogeny, while hair cell density displayed a concurrent ontogenetic decrease (excluding the utricle). There were also significant differences in macular area, hair cell number, and hair cell density between the four maculae. However, hair cell orientation patterns did not vary between individuals and did not change with body growth. These findings represent one of the first comprehensive characterisations of the inner ear sensory epithelia in an elasmobranch, and reveal changes in morphology that may have implications for auditory capabilities through ontogeny.

Cell mechanics and energetic costs of collective cell migration under confined microchannels

Mechanical force between cells relates to many biological processes of cell development. The cellular collective migration comes from cell-cell cooperation, and studying the intercellular mechanical properties helps elucidate collective cell migration. Herein, we studied cell-cell junctions, intercellular tensile force and the related cellular energetic costs in confined microchannels. Using the intercellular force sensor, we found that cells adapt to different confinement environments by regulating intercellular force, and thereby the relationship between collective cell migration and cell-cell junction were verified. Through the observation of cell orientation, actomyosin contractility, energetic costs, and glucose uptake, we can make a reasonable explanation of cell-force driven migration in different confined environments. Under highly confined conditions, the intercellular force and energetic costs are greater, and the cell orientation is more orderly. The collective migration behavior in confined spaces is closely related to the intercellular force and energetic costs, which is helpful to understand the collective migration behaviors in various confined spaces.

Fatigue behaviour of re-entrant auxetic structures made of the aluminium alloy AA7075-T651

An investigation of the fatigue behaviour of the re-entrant auxetic structures made of the aluminium alloy AA 7075-T651 is presented in this study. The analysed auxetic structures represent a new class of cellular structures that show anomalous deformation responses such as negative Poisson’s ratio. In the proposed work, the influence of the unit cell orientation on the crack path and fatigue life was studied using experimental and computational approaches. The Low Cycle Fatigue (LCF) tests were performed at load control with the load ratio 0.1 in tension. In the LCF tests five loading levels were selected, and at least two tests were performed at each loading level. The same loading conditions were then applied in the computational model in the framework of the ANSYS software package, where a nonlinear kinematic material model was applied to obtain the stress–strain relationship. The strain-life approach, with consideration of the Morrow mean stress correction, was then used to obtain the fatigue life of the analysed auxetic structures. The experimental and computational results showed that the unit cell’s orientation has a minor influence on the fatigue life of both analysed auxetic structures, but impact on the direction of the fatigue failure path significantly.

Improved light-weighting potential of SS316L triply periodic minimal surface shell lattices by micro laser powder bed fusion

Micro laser powder bed fusion (μLPBF), for the first time, enables fabrication of low-density triply periodic minimal surface (TPMS) shell lattices with smaller feature size. However, the understandings on the mechanical responses of lightweight TPMS structures by μLPBF are yet to be updated. Herein, stainless steel 316L TPMS shell lattices (i.e., Primitive (P), Diamond (D) and Gyroid (G)) with different shell thicknesses and cell orientations were fabricated by µLPBF. Low-density TPMS structures with shell thickness as small as ∼100 μm and relative density ∼5 % were realized. Quasi-static compression tests and finite element modelling were conducted to study their compressive responses. Their light-weighting potential related to the scaling behavior of mechanical properties as a function of relative density was analyzed. Results show with increasing relative density, the deformation mechanism transforms from localized collapse to homogeneous bulk deformation. P-type TPMS exhibits the highest anisotropy of stiffness, strength and energy absorption capability, while G-type TPMS is near-isotropic. [100] oriented d-type TPMS shows the highest strength and best light-weighting potential. Compared with conventional LPBF, the µLPBF TPMS structures demonstrate higher mechanical properties and superior light-weighting potential. Overall, this work highlights the superiority of the µLPBF technology in fabricating lightweight TPMS structures for mechanical applications.

Pneumatic Cell Stretching Chip to Generate Uniaxial Strain Using an Elastomeric Membrane with Ridge Structure

Cyclic mechanical stretching, including uniaxial strain, has been manifested to regulate the cell morphology and functions directly. In recent years, many techniques have been developed to apply cyclic mechanical stretching to cells in vitro. Pneumatically actuated stretching is one of the extensively used methods owing to its advantages of integration, miniaturization, and long-term stretching. However, the intrinsic difficulty in fabrication and adjusting the strain mode also impedes its development and application. In this study, inspired by the topological defects principle, we incorporated a ridge structure into the membrane surface of a traditional pneumatic cavity stretching chip to regulate the strain mode. Our results showed that the surface ridge structure can directly change the equiaxial stretching mode to the standard uniaxial strain, and it is ridge width-independent. The uniaxial strain mode was further proved by the cell orientation behavior under cyclic stretching stimulation. Moreover, it is easy to realize the multimodal strain fields by controlling the width and height of the ridge and to achieve high-throughput testing by creating a cavity array using microfabrication. Together, we propose a smart method to change the surface strain field and introduce a simple, yet effective, high-throughput pneumatically actuated uniaxial stretching platform, which can not only realize the multimodal mechanical stimulation but also achieve multiscale mechanosensing behaviors of single-cell or multi-cell (tissue and/or organoid) mechanobiology applications.

Scale discrepancy paradox between observation and modelling in fractured reservoir models in oil and gas industry

AbstractThe appraisal and development of fractured reservoirs are challenging tasks because of the combined variations in reservoir quality and natural fracture distribution. Fracture models are built routinely to support both appraisal and development decisions for such reservoirs. One of the key objectives of these models is to generate three-dimensional (3D) fracture properties for dynamic flow simulations. In this paper, we illustrate the discrepancy between the scale of observation required to build a thorough geological understanding of the subsurface and the simplification imposed by modelling. We use a case study carried out in the context of an exploration campaign of a Cretaceous carbonate reservoir in Egypt. After describing the regional geological setting of the area, we share a series of detailed observations on open-hole logs, cores, thin-sections and borehole images. These observations are focused on reservoir architecture, fracture typology and fracture connectivity. Observations are then integrated with the regional geological context to build a conceptual fracture model and to characterize the uncertainty affecting the essential parameters of this model. The conceptual model, combined with 3D seismic data, is used to define a fracture modelling strategy. This strategy includes a drastic simplification of the conceptual model to generate 3D discrete fracture network scenarios that are calibrated using pressure communication data from the exploration wells. Another extreme simplification is then necessary to populate 3D simulation grids. In the case study presented, the key tuning parameters to obtain a dynamic match are the grid cell orientation and the width of the modelled fault damage zone.

3D printed zirconia dental implants with integrated directional surface pores combine mechanical strength with favorable osteoblast response

Dental implants need to combine mechanical strength with promoted osseointegration. Currently used subtractive manufacturing techniques require a multi-step process to obtain a rough surface topography that stimulates osseointegration. Advantageously, additive manufacturing (AM) enables direct implant shaping with unique geometries and surface topographies. In this study, zirconia implants with integrated lamellar surface topography were additively manufactured by nano-particle ink-jetting. The ISO-14801 fracture load of as-sintered implants (516±39 N) resisted fatigue in 5–55 °C water thermo-cycling (631±134 N). Remarkably, simultaneous mechanical fatigue and hydrothermal aging at 90 °C significantly increased the implant strength to 909±280 N due to compressive stress generated at the seamless transition of the 30–40 µm thick, rough and porous surface layer to the dense implant core. This unique surface structure induced an elongated osteoblast morphology with uniform cell orientation and allowed for osteoblast proliferation, long-term attachment and matrix mineralization. In conclusion, the developed AM zirconia implants not only provided high long-term mechanical resistance thanks to the dense core along with compressive stress induced at the transition zone, but also generated a favorable osteoblast response owing to the integrated directional surface pores. Statement of significanceZirconia ceramics are becoming the material of choice for metal-free dental implants, however significant efforts are required to obtain a rough/porous surface for enhanced osseointegration, along with the risk of surface delamination and/or microstructure variation. In this study, we addressed the challenge by additively manufacturing implants that seamlessly combine dense core with a porous surface layer. For the first time, a unique surface with a directional lamellar pore morphology was additively obtained. This AM implant also provided strength as strong as conventionally manufactured zirconia implants before and after long-term fatigue. Favorable osteoblast response was proved by in-vitro cell investigation. This work demonstrated the opportunity to AM fabricate novel ceramic implants that can simultaneously meet the mechanical and biological functionality requirements.

A Review of Single‐Cell Pose Adjustment and Puncture

Single‐cell manipulation technology is an essential method of cell research, with wide applications in biological engineering, medical engineering, agricultural engineering, and other precise manipulation fields. Cell pose adjustment and cell puncture are considered as two basic operations of single‐cell manipulation. Cell pose adjustment can be used for cell sorting, cell trapping, cell orientation, cell transportation, etc. It consists of direct contact manipulation methods and noncontact manipulation methods (e.g., mechanical contact method, electric field, optical field, magnetic field, acoustic field, and hydrodynamic methods). Cell puncture consists of ordinary glass needle puncture methods, piezoelectric‐assisted puncture methods, and rotational oscillatory drill puncture methods. It aims to achieve directional and quantified injection or sampling with minimal damage. Herein, the recent research progress on single‐cell pose adjustment and puncture methods is systematically summarized and discussed, which involves the basic mechanism, characteristics, limitations, and applications. Some potential directions for future research are proposed in accordance with the above analysis. It is hoped that this review can provide a reference for academic research and industrial applications of single‐cell manipulation technology.

Insight and Recent Advances into the Role of Topography on the Cell Differentiation and Proliferation on Biopolymeric Surfaces.

It is well known that surface topography plays an important role in cell behavior, including adhesion, migration, orientation, elongation, proliferation and differentiation. Studying these cell functions is essential in order to better understand and control specific characteristics of the cells and thus to enhance their potential in various biomedical applications. This review proposes to investigate the extent to which various surface relief patterns, imprinted in biopolymer films or in polymeric films coated with biopolymers, by utilizing specific lithographic techniques, influence cell behavior and development. We aim to understand how characteristics such as shape, dimension or chemical functionality of surface relief patterns alter the orientation and elongation of cells, and thus, finally make their mark on the cell proliferation and differentiation. We infer that such an insight is a prerequisite for pushing forward the comprehension of the methodologies and technologies used in tissue engineering applications and products, including skin or bone implants and wound or fracture healing.

(Digital Presentation) Reusing Li-Ion Batteries in Second-Life Applications: Impact of Cell Orientation in Electric Vehicle Pack

Li-ion batteries (LiBs) in electric vehicles (EVs) finish their life with a significant amount of capacity left in them (about 80% of the nominal capacity), which provides a promising avenue for reusing the spent EV-batteries in less demanding second-life applications, such as grid-scale energy storage for peak shaving, EV charging, storage for intermittent energy sources (solar or wind power), backup storage for industries and property owners, and less demanding vehicle propulsion (ferries or forklifts) [1, 2]. However, reusing spent EV batteries in second-life applications is not as straightforward as taking a battery pack from an EV then installing it directly into a second-life application. One must consider the state-of-health (SoH) of the battery packs and hence the modules and cells to avoid any mismatch in terms of capacity, state-of-charge/depth-of-discharge (SoC/DoD). Even within the batteries suitable for reuse, cells must be sorted by similar remaining capacity and identical degradation state, or else the second-life system performance would suffer. The SoH needs careful assessment and ageing conditions evaluated to send heavily degraded batteries to recycling facilities. Whilst assessing the SoH is straightforward [3], identifying the ageing condition is complex, as ageing and degradation of LiBs over time are caused by various factors, including charging/discharging rate (C-rate), operating temperature, lifetime, SoC, and cycling [2]. Moreover, pack design, configuration, cooling methods as well as cell/module’s orientation in a pack can influence the battery degradation.In the present study, the effect of cell orientation on battery ageing and degradation has been investigated that can have an impact on the life of a battery in second-life applications. Eight large-size pouch batteries from two differently orientated modules from a dismantled first-generation Nissan Leaf retired battery pack have been analysed utilising infrared (IR) thermography and electrochemical impedance spectroscopy (EIS) techniques along with a brand-new second-generation Nissan Leaf battery which has almost the same geometry as batteries from the retired pack. Temperature derivative maps over the battery surface during discharging have been analysed, which show a direct correlation with the battery’s heat generation rates. Obtained results show that the thermal behaviour of brand-new batteries in orientations mimicking aged battery's orientation in the pack during EV life are very similar showing that the temperature derivative map’s hot spot is more towards the edge opposite to gravity vector (Figure 1 left). Also, EIS results (RCT+RSEI, charge transfer and solid electrolyte interphase layer resistances) show a wider range over SoCs for rotated-aged than flat-aged cells (Figure 1 right). It is worth noting that cells aged in flat orientation retained higher capacity compared to the cells aged in rotated orientation. These results show that different LiB orientations in EV batteries cause ageing non-uniformities over the battery surface, which would impact their second-life applications [4]. Non-uniform ageing is found to be more pronounced for the rotated module compared with the flat orientation inside the battery pack (Figure 1). Based on the present results, it is clear that avoiding different orientations in the battery pack can be a sustainable design for future EV battery back if reusing of spent EV batteries is envisaged.This work was part of the ReLiB project (https://relib.org.uk) and was supported by the Faraday Institution (https://www.faraday.ac.uk; grant numbers FIRG005 and FIRG027).

Construction of a Human Aorta Smooth Muscle Cell Organ-On-A-Chip Model for Recapitulating Biomechanical Strain in the Aortic Wall.

Conventional two-dimensional cell culture techniques and animal models have been used in the study of human thoracic aortic aneurysm and dissection (TAAD). However, human TAAD sometimes cannot be characterized by animal models. There is an apparent species gap between clinical human studies and animal experiments that may hinder the discovery of therapeutic drugs. In contrast, the conventional cell culture model is unable to simulate in vivo biomechanical stimuli. To this end, microfabrication and microfluidic techniques have developed greatly in recent years, providing novel techniques for establishing organoids-on-a-chip models that replicate the biomechanical microenvironment. In this study, a human aorta smooth muscle cell organ-on-a-chip (HASMC-OOC) model was developed to simulate the pathophysiological parameters of aortic biomechanics, including the amplitude and frequency of cyclic strain experienced by human aortic smooth muscle cells (HASMCs) that play a vital role in TAAD. In this model, the morphology of HASMCs became elongated in shape, aligned perpendicularly to the strain direction, and presented a more contractile phenotype under strain conditions than under static conventional conditions. This was consistent with the cell orientation and phenotype in native human aortic walls. Additionally, using bicuspid aortic valve-related TAAD (BAV-TAAD) and tricuspid aortic valve-related TAAD (TAV-TAAD) patient-derived primary HASMCs, we established BAV-TAAD and TAV-TAAD disease models, which replicate HASMC characteristics in TAAD. The HASMC-OOC model provides a novel in vitro platform that is complementary to animal models for further exploring the pathogenesis of TAAD and discovering therapeutic targets.

Edible films for cultivated meat production

Biomaterial scaffolds are critical components in cultivated meat production for enabling cell adhesion, proliferation, differentiation and orientation. Currently, there is limited information on the fabrication of edible/biodegradable scaffolds for cultivated meat applications. In the present work, several abundant, naturally derived biomaterials (gelatin, soy, glutenin, zein, cellulose, alginate, konjac, chitosan) were fabricated into films without toxic cross-linking or stabilizing agents. These films were investigated for support of the adhesion, proliferation and differentiation of murine and bovine myoblasts. These biomaterials supported cell viability, and the protein-based films showed better cell adhesion than the polysaccharide-based films. Surface patterns induced cell alignment and guided myoblast differentiation and organization on the glutenin and zein films. The mechanical properties of the protein films were also assessed and suggested that a range of properties can be achieved to meet food-related goals. Overall, based on adherence, proliferation, differentiation, mechanics, and material availability, protein-based films, particularly glutenin and zein, showed the most promise for cultivated meat applications. Ultimately, this work presents a comparison of suitable biomaterials for cultivated meat applications and suggests future efforts to optimize scaffolds for efficacy and cost.

In-plane and out-plane flexural properties of the bird feather-inspired panels: Experimental, digital image correlation, and finite element study

In this study, the flexural performance of the novel bird's feather-inspired cellular panels has been studied. All the panels are fabricated using the fused filament fabrication (FFF) method with acrylonitrile butadiene styrene (ABS) plus material. Both the in-plane and out-plane flexural response is studied under a three-point bending load. The panels were designed to study the effect of unit cell length and orientation on stiffness, strength, energy absorption, and crack propagation. The in-situ digital image correlation (DIC) technique has been used to visualize the deflection field of the panels. Furthermore, finite element modeling (FEM) is also used to visualize the plastic strain and stress in the panels. Results showed an increase in stiffness and flexural strength with a decrease in the unit cell length. The change in orientation of the unit cell length can significantly increase the flexural performance of both the in-panels and out-plane loaded panels. The panels loaded in the in-plane three-point loading showed higher energy absorption, whereas panels loaded in out-plane three-point loading showed higher stiffness and flexural strength. Finally, the flexural performance of the new bionic panels is compared with the other type of panels reported in the literature. The new bionic panels show significant improvement over the previous designs. The current study provides novel lightweight panels with improved flexural properties, which can also be helpful for researchers working in the design field. From the design point of view, novel designs can be used in applications like ship floors, aircraft bodies, construction, etc.

Imaging mass cytometry reveals the prominent role of myeloid cells at the maternal-fetal interface

SummaryAlthough the immunological complexity of the maternal-fetal interface is well appreciated, the actual interaction of maternal immune cells and fetal trophoblasts is insufficiently understood. To comprehend the composition and spatial orientation of maternal immune cells and fetal extravillous trophoblasts, we applied imaging mass cytometry on decidua basalis of the three trimesters of healthy pregnancy. Within all trimesters, we observed considerably higher frequencies of myeloid cells in the decidua than is seen with single-cell suspension techniques. Moreover, they were the most pronounced cell type in the microenvironment of other decidual cells. In first trimester, HLA-DR- macrophages represented the most abundant myeloid subcluster and these cells were frequently observed in the vicinity of trophoblasts. At term, HLA-DR+ macrophage subclusters were abundantly present and frequently observed in the microenvironment of T cells. Taken together, our results highlight the dynamic role of myeloid cells at the human maternal-fetal interface throughout gestation.

Size-Dependent Behaviour of Representative Volume Element for Granular Material under Gravity-Induced Stress Gradient

Gravity is the primary load source in geotechnical engineering, and its effect becomes extremely important in these cases such as lunar research station construction and in situ resource utilization. However, at the current stage, the study on the effect of gravity-induced stress gradients on the behavior of geomaterials is seriously lacking. In this work, the size-dependent behaviour of representative volume element (RVE) of granular matter under the gravity-induced stress gradient is studied. A homogenization theory is proposed firstly, which homogenizes the granular matter into stress gradient continuum through RVE. Then, numerical triaxial loading for RVEs with various heights and particle sizes is carried out under 0∼10 g gravity. The results show that the size effect and its origination appear to have no obvious influence on isotropic compression. However, the macroscopic shear strength, elastic modulus, and volumetric deformation all show size effect dependence, and the gravity-induced stress gradient leads to significant differences between different originations of size effect. The valence, orientation, and elongation degree of microscopic void cells are further analyzed, which suggests that applying of stress gradient results in the evolution of void cells demonstrates a dependence on both the size effect and its origination. The results indicate that the gravity-induced stress gradient and corresponding size effect should be paid sufficient attention to granular mechanics of terrestrial and off-earth engineering.

Acoustic Fabrication of Living Cardiomyocyte-based Hybrid Biorobots.

Organized assemblies of cells have demonstrated promise as bioinspired actuators and devices; still, the fabrication of such "biorobots" has predominantly relied on passive assembly methods that reduce design capabilities. To address this, we have developed a strategy for the rapid formation of functional biorobots composed of live cardiomyocytes. We employ tunable acoustic fields to facilitate the efficient aggregation of millions of cells into high-density macroscopic architectures with directed cell orientation and enhanced cell-cell interaction. These biorobots can perform actuation functions both through naturally occurring contraction-relaxation cycles and through external control with chemical and electrical stimuli. We demonstrate that these biorobots can be used to achieve controlled actuation of a soft skeleton and pumping of microparticles. The biocompatible acoustic assembly strategy described here should prove generally useful for cellular manipulation in the context of tissue engineering, soft robotics, and other applications.

Role of an auxilliary subunit of voltage-gated Na+ channels in endothelial functions: Is Navβ3, a novel actor of vascular mechanosignaling?

The endothelial cell (EC) is a central actor to maintain vascular tone and homeostasis. Endothelial dysfunction is responsible for the development of many cardiovascular diseases including atherosclerosis. The endothelial function is mainly stimulated by the shear stress generated by blood flow. The physical forces produced by flow are detected by many mechanosensors in EC, which trigger intracellular signaling pathways influencing endothelial physiology. Among these mechanosensors, several ion channels have been identified. Voltage-gated Na+ (Nav) channels have been shown to be mechanosensitive in cardiac and intestinal cells. These ion channels are also expressed in EC and then we aim to investigate their role in EC responses to shear stress. Confluent Human Umbilical Vein EC (HUVEC) and Human Aorta EC (teloHAEC) were exposed to laminar (LSS, 20 dynes/cm 2 ) or oscillatory shear stress (OSS, 20 dynes/cm 2 , 0.5 Hz frequency) using the Ibidi® pump system. Cell orientation was quantified by local gradient orientation method with Fiji software. RTqPCR and western blot were used to characterize Nav channel subunits at both transcriptional and protein levels. Exposition of HUVEC and TeloHAEC to a LSS for 24 hours and 4 days induced cell orientation in the direction of flow and activated the atheroprotective signaling pathway (KLF2/KLF4, eNOS). Interestingly, shear stress deep changes in several Nav channels subunits expression level. Notably, SCN3B expression, encoding the Ig-CAM Navβ3 protein, was increased with a 2.1 fold increase at 24 hours, 3.9 at 4 days and 12.6 at 7 days in HUVEC and 2.9 at 4 days in teloHAEC. Moreover, trans-resveratrol-induced KLF2 expression led to increase SCN3B expression, suggesting that this atheroprotective transcription factor might be involved in SCN3B regulation. Indeed, OSS, corresponding to an atherogenic flow, did not induce HUVEC alignment in the direction of flow neither activation of atheroprotective signaling pathway nor a significant increase of SCN3B expression. Taken together, our results suggest that Navβ3 could be a putative novel actor in the mechanotransduction of flow and thus in vasculoprotection.

Guiding cell migration in 3D with high-resolution photografting

Multi-photon lithography (MPL) has proven to be a suitable tool to precisely control the microenvironment of cells in terms of the biochemical and biophysical properties of the hydrogel matrix. In this work, we present a novel method, based on multi-photon photografting of 4,4′-diazido-2,2′-stilbenedisulfonic acid (DSSA), and its capabilities to induce cell alignment, directional cell migration and endothelial sprouting in a gelatin-based hydrogel matrix. DSSA-photografting allows for the fabrication of complex patterns at a high-resolution and is a biocompatible, universally applicable and straightforward process that is comparably fast. We have demonstrated the preferential orientation of human adipose-derived stem cells (hASCs) in response to a photografted pattern. Co-culture spheroids of hASCs and human umbilical vein endothelial cells (HUVECs) have been utilized to study the directional migration of hASCs into the modified regions. Subsequently, we have highlighted the dependence of endothelial sprouting on the presence of hASCs and demonstrated the potential of photografting to control the direction of the sprouts. MPL-induced DSSA-photografting has been established as a promising method to selectively alter the microenvironment of cells.