Reprogramming the Stem Cell Behavior by Shear Stress and Electric Field Stimulation: Lab-on-a-Chip Based Biomicrofluidics in Regenerative Medicine

Regenerative bioelectronics: A strategic roadmap for precision medicine

In the past few decades, stem cell-based regenerative engineering has demonstrated its significant potential to repair damaged tissues and to restore their functionalities. Despite such advancement in regenerative engineering, the clinical translation remains a major challenge. In the stance of personalized treatment, the recent progress in bioelectronic medicine likewise evolved as another important research domain of larger significance for human healthcare. Over the last several years, our research group has adopted biomaterials-based regenerative engineering strategies using innovative bioelectronic stimulation protocols based on either electric or magnetic stimuli to direct cellular differentiation on engineered biomaterials with a range of elastic stiffness or functional properties (electroactivity/magnetoactivity). In this article, the role of bioelectronics in stem cell-based regenerative engineering has been critically analyzed to stimulate futuristic research in the treatment of degenerative diseases as well as to address some fundamental questions in stem cell biology. Built on the concepts from two independent biomedical research domains (regenerative engineering and bioelectronic medicine), we propose a converging research theme, 'Regenerative Bioelectronics'. Further, a series of recommendations have been put forward to address the current challenges in bridging the gap in stem cell therapy and bioelectronic medicine. Enacting the strategic blueprint of bioelectronic-based regenerative engineering can potentially deliver the unmet clinical needs for treating incurable degenerative diseases.

Acoustofluidic large-scale mixing for enhanced microfluidic immunostaining for tissue diagnostics

The usage of microfluidics for automated and fast immunoassays has gained a lot of interest in the last decades. This integration comes with certain challenges, like the reconciliation of laminar flow patterns of micro-scale systems with diffusion-limited mass transport. Several methods have been investigated to enhance microfluidic mixing in microsystems, including acoustic-based fluidic streaming. Here, we report both by numerical simulation and experiments on the beneficiary effect of acoustic agitation on the uniformity of immunostaining in large-size and thin microfluidic chambers. Moreover, we investigate by numerical simulation the impact of reducing the incubation times and the concentrations of the biochemical detection reagents on the obtained immunoassay signal. Finally, acoustofluidic mixing was successfully used to reduce by 80% the incubation time of the Her2 (human epidermal growth factor receptor 2) and CK (cytokeratins) biomarkers for the spatial immunostaining of breast cancer cell pellets, or reducing their concentration by 66% and achieving a higher signal-to-background ratio than comparable spatially resolved immunostaining with static incubation.

Organs-on-Chips Platforms Are Everywhere: A Zoom on Biomedical Investigation

Over the decades, conventional in vitro culture systems and animal models have been used to study physiology, nutrient or drug metabolisms including mechanical and physiopathological aspects. However, there is an urgent need for Integrated Testing Strategies (ITS) and more sophisticated platforms and devices to approach the real complexity of human physiology and provide reliable extrapolations for clinical investigations and personalized medicine. Organ-on-a-chip (OOC), also known as a microphysiological system, is a state-of-the-art microfluidic cell culture technology that sums up cells or tissue-to-tissue interfaces, fluid flows, mechanical cues, and organ-level physiology, and it has been developed to fill the gap between in vitro experimental models and human pathophysiology. The wide range of OOC platforms involves the miniaturization of cell culture systems and enables a variety of novel experimental techniques. These range from modeling the independent effects of biophysical forces on cells to screening novel drugs in multi-organ microphysiological systems, all within microscale devices. As in living biosystems, the development of vascular structure is the salient feature common to almost all organ-on-a-chip platforms. Herein, we provide a snapshot of this fast-evolving sophisticated technology. We will review cutting-edge developments and advances in the OOC realm, discussing current applications in the biomedical field with a detailed description of how this technology has enabled the reconstruction of complex multi-scale and multifunctional matrices and platforms (at the cellular and tissular levels) leading to an acute understanding of the physiopathological features of human ailments and infections in vitro.

Biomaterialomics: Data science-driven pathways to develop fourth-generation biomaterials

Conventional approaches to developing biomaterials and implants require intuitive tailoring of manufacturing protocols and biocompatibility assessment. This leads to longer development cycles, and high costs. To meet existing and unmet clinical needs, it is critical to accelerate the production of implantable biomaterials, implants and biomedical devices. Building on the Materials Genome Initiative, we define the concept 'biomaterialomics' as the integration of multi-omics data and high-dimensional analysis with artificial intelligence (AI) tools throughout the entire pipeline of biomaterials development. The Data Science-driven approach is envisioned to bring together on a single platform, the computational tools, databases, experimental methods, machine learning, and advanced manufacturing (e.g., 3D printing) to develop the fourth-generation biomaterials and implants, whose clinical performance will be predicted using 'digital twins'. While analysing the key elements of the concept of 'biomaterialomics', significant emphasis has been put forward to effectively utilize high-throughput biocompatibility data together with multiscale physics-based models, E-platform/online databases of clinical studies, data science approaches, including metadata management, AI/ Machine Learning (ML) algorithms and uncertainty predictions. Such integrated formulation will allow one to adopt cross-disciplinary approaches to establish processing-structure-property (PSP) linkages. A few published studies from the lead author's research group serve as representative examples to illustrate the formulation and relevance of the 'Biomaterialomics' approaches for three emerging research themes, i.e. patient-specific implants, additive manufacturing, and bioelectronic medicine. The increased adaptability of AI/ML tools in biomaterials science along with the training of the next generation researchers in data science are strongly recommended. STATEMENT OF SIGNIFICANCE: This leading opinion review paper emphasizes the need to integrate the concepts and algorithms of the data science with biomaterials science. Also, this paper emphasizes the need to establish a mathematically rigorous cross-disciplinary framework that will allow a systematic quantitative exploration and curation of critical biomaterials knowledge needed to drive objectively the innovation efforts within a suitable uncertainty quantification framework, as embodied in 'biomaterialomics' concept, which integrates multi-omics data and high-dimensional analysis with artificial intelligence (AI) tools, like machine learning. The formulation of this approach has been demonstrated for patient-specific implants, additive manufacturing, and bioelectronic medicine.

Fluid Flow Dependency in Immunoselective Cell Capture via Liquid Biopsy

Liquid biopsy targets rare cells that overexpress disease-specific membrane markers and capture these cells via immunoaffinity. The diagnosis efficiency of liquid biopsy can be impaired by the presence of healthy adherent cells also expressing the same biomarkers. Here, we investigated the effect of settling times and rinsing flow rates on the efficiency of EpCAM-based immunocapture using both simulation and experiments with three different cell types. Cell-surface adhesion forces and shear rates were calculated to define the range of rinsing flow rates to test experimentally. Healthy adherent cells did not adhere to blocked immunofunctionalized surfaces within the timeframe of the experiment; however, healthy EpCAM positive cells did bind to the surface to some extent. The greatest difference in capture efficiency was obtained using a high rinsing flow rate of 25 mL/min following 40 min static incubation, indicating that optimizing rinsing flow rates could be a viable option to capture, more specifically, cancer cells overexpressing EpCAM.

Bioscaffolds embedded with regulatory modules for cell growth and tissue formation: A review

The demand for artificial organs has greatly increased because of various aging-associated diseases and the wide need for organ transplants. A recent trend in tissue engineering is the precise reconstruction of tissues by the growth of cells adhering to bioscaffolds, which are three-dimensional (3D) structures that guide tissue and organ formation. Bioscaffolds used to fabricate bionic tissues should be able to not only guide cell growth but also regulate cell behaviors. Common regulation methods include biophysical and biochemical stimulations. Biophysical stimulation cues include matrix hardness, external stress and strain, surface topology, and electromagnetic field and concentration, whereas biochemical stimulation cues include growth factors, proteins, kinases, and magnetic nanoparticles. This review discusses bioink preparation, 3D bioprinting (including extrusion-based, inkjet, and ultraviolet-assisted 3D bioprinting), and regulation of cell behaviors. In particular, it provides an overview of state-of-the-art methods and devices for regulating cell growth and tissue formation and the effects of biophysical and biochemical stimulations on cell behaviors. In addition, the fabrication of bioscaffolds embedded with regulatory modules for biomimetic tissue preparation is explained. Finally, challenges in cell growth regulation and future research directions are presented.

Organ-on-a-chip: the next generation platform for risk assessment of radiobiology

Organ-on-a-chip devices have been widely used in biomedical science and technology, for example for experimental regenerative medicine and precision healthcare. The main advantage of organ-on-a-chip technology is the facility to build a specific human model that has functional responses on the level of organs or tissues, thereby avoiding the use of animal models, as well as greatly improving new drug discovery processes for personal healthcare. An emerging application domain for organs-on-chips is the study of internal irradiation for humans, which faces the challenges of the lack of a clear model for risk estimation of internal irradiation. We believe that radiobiology studies will benefit from organ-on-a-chip technology by building specific human organ/tissues in vitro. In this paper, we briefly reviewed the state-of-the-art in organ-on-a-chip research in different domains, and conclude with the challenges of radiobiology studies at internal low-dose irradiation. Organ-on-a-chip technology has the potential to significantly improve the radiobiology study as it can mimic the function of human organs or tissues, and here we summarize its potential benefits and possible breakthrough areas, as well as its limitations in internal low-dose radiation studies.

Organ-on-a-chip technology has great potential for the next generation risk estimation of low dose internal irradiation, due to its success in mimicking human organs/tissues, which possibly can significantly improve on current animal models.