Surface-Enhanced Raman Scattering Monitoring of Tryptophan Dynamics in 3D Pancreatic Tumor Models.

In the intricate landscape of the tumor microenvironment, both cancer and stromal cells undergo rapid metabolic adaptations to support their growth. Given the relevant role of the metabolic secretome in fueling tumor progression, its unique metabolic characteristics have gained prominence as potential biomarkers and therapeutic targets. As a result, rapid and accurate tools have been developed to track metabolic changes in the tumor microenvironment with high sensitivity and resolution. Surface-enhanced Raman scattering (SERS) is a highly sensitive analytical technique and has been proven efficient toward the detection of metabolites in biological media. However, profiling secreted metabolites in complex cellular environments such as those in tumor-stroma 3D in vitro models remains challenging. To address this limitation, we employed a SERS-based strategy to investigate the metabolic secretome of pancreatic tumor models within 3D cultures. We aimed to monitor the immunosuppressive potential of stratified pancreatic cancer-stroma spheroids as compared to 3D cultures of either pancreatic cancer cells or cancer-associated fibroblasts, focusing on the metabolic conversion of tryptophan into kynurenine by the IDO-1 enzyme. We additionally sought to elucidate the dynamics of tryptophan consumption in correlation with the size, temporal evolution, and composition of the spheroids, as well as assessing the effects of different drugs targeting the IDO-1 machinery. As a result, we confirm that SERS can be a valuable tool toward the optimization of cancer spheroids, in connection with their tryptophan metabolizing capacity, potentially allowing high-throughput spheroid analysis.

Exploring the role of microRNAs as diagnostic and prognostic biomarkers in canine mammary tumors.

Canine mammary tumors (CMTs) represent a significant health concern in dogs, with a high incidence among intact female dogs. CMTs are a promising comparative model for human breast cancer, due to sharing several pathophysiological features. Additionally, CMTs have a strong genetic correlation with their human counterpart, including the expression of microRNAs (miRNAs). MiRNAs are a class of non-coding RNAs that play important roles in post-translational regulation of gene expression, being implicated in carcinogenesis, tumor progression, and metastasis. Moreover, miRNAs hold promise as diagnostic, prognostic, and metastatic biomarkers. Understanding the molecular mechanisms underlying CMTs is crucial for improving diagnosis, prognosis, and monitoring of treatments. Herein, we provide a comprehensive overview of the current knowledge on miRNAs in CMTs, highlighting their roles in carcinogenesis and their potential as biomarkers. Additionally, we highlight the current limitations and critically discuss the overarching challenges in this field, emphasizing the need for future research to translate miRNA findings into veterinary clinical practice.

Human Platelet Lysate-Derived Nanofibrils as Building Blocks to Produce Free-Standing Membranes for Cell Self-Aggregation.

Amyloid-like fibrils are garnering keen interest in biotechnology as supramolecular nanofunctional units to be used as biomimetic platforms to control cell behavior. Recent insights into fibril functionality have highlighted their importance in tissue structure, mechanical properties, and improved cell adhesion, emphasizing the need for scalable and high-kinetics fibril synthesis. In this study, we present the instantaneous and bulk formation of amyloid-like nanofibrils from human platelet lysate (PL) using the ionic liquid cholinium tosylate as a fibrillating agent. The instant fibrillation of PL proteins upon supramolecular protein-ionic liquid interactions was confirmed from the protein conformational transition toward cross-ß-sheet-rich structures. These nanofibrils were utilized as building blocks for the formation of thin and flexible free-standing membranes via solvent casting to support cell self-aggregation. These PL-derived fibril membranes reveal a nanotopographically rough surface and high stability over 14 days under cell culture conditions. The culture of mesenchymal stem cells or tumor cells on the top of the membrane demonstrated that cells are able to adhere and self-organize in a three-dimensional (3D) spheroid-like microtissue while tightly folding the fibril membrane. Results suggest that nanofibril membrane incorporation in cell aggregates can improve cell viability and metabolic activity, recreating native tissues' organization. Altogether, these PL-derived nanofibril membranes are suitable bioactive platforms to generate 3D cell-guided microtissues, which can be explored as bottom-up strategies to faithfully emulate native tissues in a fully human microenvironment.

Acidochromic Free-Standing Multilayered Chitosan-Pyranoflavylium/Alginate Membranes toward Food Smart Packaging Applications.

Food smart packaging has emerged as a promising technology to address consumer concerns regarding food conservation and food safety. In this context, we report the rational design of azide-containing pyranoflavylium-based pH-sensitive dye for subsequent click chemistry conjugation toward a chitosan-modified alkyne. The chitosan-pyranoflavylium conjugate was characterized by infrared (ATR-FTIR), ultraviolet-visible (UV-vis), nuclear magnetic resonance (NMR) spectroscopies, and dynamic light scattering (DLS), as well as its thermodynamic parameters related to their pH-dependent chromatic features. The fabrication of thin-films through electrostatic-driven layer-by-layer (LbL) assembly technology was first screened by quartz crystal microbalance with dissipation monitoring (QCM-D) onto gold substrates, and then free-standing (FS) multilayered membranes from polypropylene substrate were obtained using a homemade automatic dipping robot. The membranes' characterization included morphology analysis and thickness evaluation, assessed by scanning electron microscopy (SEM), pH-responsive color change performance tests using buffer solutions at different pH levels, and biogenic amines-enriched model solutions, demonstrating the feasibility and effectiveness of the chitosan-pyranoflavylium/alginate biomembranes for food spoilage monitoring. This work provides insights toward the development of innovative pH-responsive smart biomaterials for advanced and sustainable technological packaging solutions, which could significantly contribute to ensuring food safety and quality, while reducing food waste.

Contribution of non-steroidal anti-inflammatory drugs to breast cancer treatment: In vitro and in vivo studies.

Chronic inflammation plays a crucial role in carcinogenesis. High levels of serum prostaglandin E2 and tissue overexpression of cyclooxygenase-2 (COX-2) have been described in breast, urinary, colorectal, prostate, and lung cancers as being involved in tumor initiation, promotion, progression, angiogenesis, and immunosuppression. Non-steroidal anti-inflammatory drugs (NSAIDs) are prescribed for several medical conditions to not only decrease pain and fever but also reduce inflammation by inhibiting COX and its product synthesis. To date, significant efforts have been made to better understand and clarify the interplay between cancer development, inflammation, and NSAIDs with a view toward addressing their potential for cancer management. This review provides readers with an overview of the potential use of NSAIDs and selective COX-2 inhibitors for breast cancer treatment, highlighting pre-clinical in vitro and in vivo studies employed to evaluate the efficacy of NSAIDs and their use in combination with other antineoplastic drugs.

Modeling 3D Tumor Invasiveness to Modulate Macrophage Phenotype in a Human-Based Hydrogel Platform.

The immune system is a pivotal player in determining tumor fate, contributing to the immunosuppressive microenvironment that supports tumor progression. Considering the emergence of biomaterials as promising platforms to mimic the tumor microenvironment, human platelet lysate (PLMA)-based hydrogel beads are proposed as 3D platforms to recapitulate the tumor milieu and recreate the synergistic tumor-macrophage communication. Having characterized the biomaterial-mediated pro-regenerative macrophage phenotype, an osteosarcoma spheroid encapsulated into a PLMA hydrogel bead is explored to study macrophage immunomodulation through paracrine signaling. The culture of PLMA-Tumor beads on the top of a 2D monolayer of macrophages reveals that tumor cells triggered morphologic and metabolic adaptations in macrophages. The cytokine profile, coupled with the upregulation of gene and protein anti-inflammatory biomarkers clearly indicates macrophage polarization toward an M2-like phenotype. Moreover, the increased gene expression of chemokines identified as pro-tumoral environmental regulators suggest a tumor-associated macrophage phenotype, exclusively stimulated by tumor cells. This pro-tumoral microenvironment is also found to enhance tumor invasiveness ability and proliferation. Besides providing a robust in vitro immunomodulatory tumor model that faithfully recreates the tumor-macrophage interplay, this human-based platform has the potential to provide fundamental insights into immunosuppressive signaling and predict immune-targeted response.

Photoacoustic processing of decellularized extracellular matrix for biofabricating living constructs.

The diverse biomolecular landscape of tissue-specific decellularized extracellular matrix (dECM) biomaterials provides a multiplicity of bioinstructive cues to target cells, rendering them highly valuable for various biomedical applications. However, the isolation of dECM biomaterials entails cumbersome xenogeneic enzymatic digestions and also additional inactivation procedures. Such, increases processing time, increments costs and introduces residues of non-naturally present proteins in dECM formulations that remain present even after inactivation. To overcome these limitations, herein we report an innovative conjugation of light and ultrasound-mediated dECM biomaterial processing for fabricating dECM biomaterials. Such approach gathers on ultrasound waves to facilitate dECM-in-liquid processing and visible light photocrosslinking of tyrosine residues naturally present in dECM biomaterials. This dual step methodology unlocked the in-air production of cell laden dECM hydrogels or programmable dECM hydrogel spherical-like beads by using superhydrophobic surfaces. These in-air produced units do not require any additional solvents and successfully supported both fibroblasts and breast cancer cells viability upon encapsulation or surface seeding. In addition, the optimized photoacoustic methodology also enabled a rapid formulation of dECM biomaterial inks with suitable features for biofabricating volumetrically defined living constructs through embedded 3D bioprinting. The biofabricated dECM hydrogel constructs supported cell adhesion, spreading and viability for 7 days. Overall, the implemented photoacoustic processing methodology of dECM biomaterials offers a rapid and universal strategy for upgrading their processing from virtually any tissue. STATEMENT OF SIGNIFICANCE: Leveraging decellularized extracellular matrix (dECM) as cell instructive biomaterials has potential to open new avenues for tissue engineering and in vitro disease modelling. The processing of dECM remains however, lengthy, costly and introduces non-naturally present proteins in the final biomaterials formulations. In this regard, here we report an innovative light and ultrasound two-step methodology that enables rapid dECM-in-liquid processing and downstream photocrosslinking of dECM hydrogel beads and 3D bioprinted constructs. Such photoacoustic based processing constitutes a universally applicable method for processing any type of tissue-derived dECM biomaterials.

Shape-Versatile Fixed Cellular Materials for Multiple Target Immunomodulation.

Therapeutic cells are usually administered as living agents, despite the risks of undesired cell migration and acquisition of unpredictable phenotypes. Additionally, most cell-based therapies rely on the administration of single cells, often associated with rapid in vivo clearance. 3D cellular materials may be useful to prolong the effect of cellular therapies and offer the possibility of creating structural volumetric constructs. Here, the manufacturing of shape-versatile fixed cell-based materials with immunomodulatory properties is reported. Living cell aggregates with different shapes (spheres and centimeter-long fibers) are fixed using a method compatible with maintenance of structural integrity, robustness, and flexibility of 3D constructs. The biological properties of living cells can be modulated before fixation, rendering an in vitro anti-inflammatory effect toward human macrophages, in line with a decreased activation of the nuclear factor kappa B (NF-κB) pathway that preponderantly correlated with the surface area of the materials. These findings are further corroborated in vivo in mouse skin wounds. Contact with fixed materials also reduces the proliferation of activated primary T lymphocytes, while promoting regulatory populations. The fixation of cellular constructs is proposed as a versatile phenotypic stabilization method that can be easily implemented to prepare immunomodulatory materials with therapeutic potential.

A scaffold vaccine to promote tumor antigen cross-presentation via sustained toll-like receptor-2 (TLR2) activation.

Cancer vaccination holds great promise for cancer treatment, but its effectiveness is hindered by suboptimal activation of CD8+ cytotoxic T lymphocytes, which are potent effectors to mediate anti-tumor immune responses. A possible solution is to switch antigen-presenting cells to present tumor antigens via the major histocompatibility complex class I (MHC-I) to CD8+ T cells - a process known as cross-presentation. To achieve this goal, we develop a three-dimensional (3D) scaffold vaccine to promote antigen cross-presentation by persisted toll-like receptor-2 (TLR2) activation after one injection. This vaccine comprises polysaccharide frameworks that "hook" TLR2 agonist (acGM) via tunable hydrophobic interactions and forms a 3D macroporous scaffold via click chemistry upon subcutaneous injection. Its retention-and-release of acGM enables sustained TLR2 activation in abundantly recruited dendritic cells in situ, inducing intracellular production of reactive oxygen species (ROS) in optimal kinetics that crucially promotes efficient antigen cross-presentation. The scaffold loaded with model antigen ovalbumin (OVA) or tumor specific antigen can generate potent immune responses against lung metastasis in B16-OVA-innoculated wild-type mice or spontaneous colorectal cancer in transgenic ApcMin/+ mice, respectively. Notably, it requires neither additional adjuvants nor external stimulation to function and can be adjusted to accommodate different antigens. The developed scaffold vaccine may represent a new, competent tool for next-generation personalized cancer vaccination.

Encapsulated Mesenchymal Stromal Cells as Cyclic Providers of Immunomodulatory Secretomes: A Living on-Demand Delivery System.

The stimulation of mesenchymal stromal cells (MSCs) with inflammatory molecules is often used to boost their therapeutic effect. Prolonged exposure to inflammatory molecules has been explored to improve their action because MSCs therapies seem to be improved transiently with such stimuli. However, the possibility of cyclically stimulating MSCs to recover their optimized therapeutic potential is still to be elucidated, although the efficacy of cell-based therapies may be dependent on the ability to readapt to the relapse pathological conditions. Here, the response of MSCs, encapsulated in alginate hydrogels and cultured for 22 d, is explored using three different regimes: single, continuous, and intermittent stimulation with IFNγ. Exposure to IFNγ leads to a decrease in the secretion of IL-10, which is cyclically countered by IFNγ weaning. Conditioned media collected at different stages of pulsatile stimulation show an immunomodulatory potential toward macrophages, which directly correlates with IL-10 concentration in media. To understand whether the correlation between cyclic stimulation of MSCs and other biological actions can be observed, the effect on endothelial cells is studied, showcasing an overall modest influence on tube formation. Overall, the results describe the response of encapsulated MSCs to unusual pulsatile simulation regimens, exploring encapsulated MSCs as a living on-demand release system of tailored secretomes with recoverable immunomodulatory action.

Designing of a Multifunctional 3D-Printed Biomimetic Theragenerative Aerogel Scaffold via Mussel-Inspired Chemistry: Bioactive Glass Nanofiber-Incorporated Self-Assembled Silk Fibroin with Antibacterial, Antiosteosarcoma, and Osteoinductive Properties.

Biomaterial-mediated bone tissue engineering (BTE) offers an alternative, interesting approach for the restoration of damaged bone tissues in postsurgery osteosarcoma treatment. This study focused on synthesizing innovative composite inks, integrating self-assembled silk fibroin (SF), tannic acids (TA), and electrospun bioactive glass nanofibers 70SiO2-25CaO-5P2O5 (BGNF). By synergistically combining the unique characteristics of these three components through self-assembly and microextrusion-based three-dimensional (3D) printing, our goal was to produce durable and versatile aerogel-based 3D composite scaffolds. These scaffolds were designed to exhibit hierarchical porosity along with antibacterial, antiosteosarcoma, and bone regeneration properties. Taking inspiration from mussel foot protein attachment chemistry involving the coordination of dihydroxyphenylalanine (DOPA) amino acids with ferric ions (Fe3+), we synthesized a tris-complex catecholate-iron self-assembled composite gel. This gel formation occurred through the coordination of oxidized SF (SFO) with TA and polydopamine-modified BGNF (BGNF-PDA). The dynamic nature of the coordination ligand-metal bonds within the self-assembled SFO matrix provided excellent shear-thinning properties, allowing the SFO-TA-BGNF complex gel to be extruded through a nozzle, facilitating 3D printing into scaffolds with outstanding shape fidelity. Moreover, the developed composite aerogels exhibited multifaceted features, including NIR-triggered photothermal antibacterial and in vitro photothermal antiosteosarcoma properties. In vitro studies showcased their excellent biocompatibility and osteogenic features as seeded cells successfully differentiated into osteoblasts, promoting bone regeneration in 21 days. Through comprehensive characterizations and biological validations, our antibacterial scaffold demonstrated promise as an exceptional platform for concurrent bone regeneration and bone cancer therapy, setting the stage for their potential clinical application.

Natural Polymer-Polyphenol Bioadhesive Coacervate with Stable Wet Adhesion, Antibacterial Activity, and On-Demand Detachment.

Medical adhesives are emerging as an important clinical tool as adjuvants for sutures and staples in wound closure and healing and in the achievement of hemostasis. However, clinical adhesives combining cytocompatibility, as well as strong and stable adhesion in physiological conditions, are still in demand. Herein, a mussel-inspired strategy is explored to produce adhesive coacervates using tannic acid (TA) and methacrylate pullulan (PUL-MA). TA|PUL-MA coacervates mainly comprise van der Waals forces and hydrophobic interactions. The methacrylic groups in the PUL backbone increase the number of interactions in the adhesives matrix, resulting in enhanced cohesion and adhesion strength (72.7 Jm-2), compared to the non-methacrylated coacervate. The adhesive properties are kept in physiologic-mimetic solutions (72.8 Jm-2) for 72 h. The photopolymerization of TA|PUL-MA enables the on-demand detachment of the adhesive. The poor cytocompatibility associated with the use of phenolic groups is here circumvented by mixing reactive oxygen species-degrading enzyme in the adhesive coacervate. This addition does not hamper the adhesive character of the materials, nor their anti-microbial or hemostatic properties. This affordable and straightforward methodology, together with the tailorable adhesivity even in wet environments, high cytocompatibility, and anti-bacterial activity, enables foresee TA|PUL-MA as a promising ready-to-use bioadhesive for biomedical applications.

Embedded 3D Bioprinting for Engineering Miniaturized In Vitro Tumor Models.

Embedded extrusion 3D bioprinting is a rapidly emerging additive manufacturing methodology that provides a precise spatial deposition of synthetic or natural-origin low-viscosity bioinks during the extrusion printing process. Such a strategy has to date unlocked the freeform extrusion biofabrication of complex micro-to-macro-scale living architectures for numerous applications, including tissue engineering and in vitro disease modeling. In this chapter, we describe a suspension bioprinting methodology leveraging a continuous viscoelastic biopolymer supporting bath functionalized with divalent calcium cations to enable a rapid processing of user-defined bioinks toward architecturally complex 3D in vitro tumor models. This highly simple and cost-effective viscoelastic supporting bath enables a full freeform biofabrication of cell-laden 3D tumor-mimetic architectures that exhibit structural stability in culture post-printing. The cytocompatibility of the supporting bath, its ease of removal from biofabricated living constructs, and its adaptability for processing different ECM-mimetic bioinks open avenues for multi-scale fabrication of numerous types of physiomimetic 3D tumor models for preclinical screening of candidate therapeutics.

Encapsulation of pristine and silica-coated human adipose-derived mesenchymal stem cells in gelatin colloidal hydrogels for tissue engineering and bioprinting applications.

Colloidal gels assembled from gelatin nanoparticles (GNPs) as particulate building blocks show strong promise to solve challenges in cell delivery and biofabrication, such as low cell survival and limited spatial retention. These gels offer evident advantages to facilitate cell encapsulation, but research on this topic is still limited, which hampers our understanding of the relationship between the physicochemical and biological properties of cell-laden colloidal gels. Human adipose-derived mesenchymal stem cells were successfully encapsulated in gelatin colloidal gels and evaluated their mechanical and biological performance over 7 days. The cells dispersed well within the gels without compromising gel cohesiveness, remained viable, and spread throughout the gels. Cells partially coated with silica were introduced into these gels, which increased their storage moduli and decreased their self-healing capacity after 7 days. This finding demonstrates the ability to modulate gel stiffness by incorporating cells partially coated with silica, without altering the solid content or introducing additional particles. Our work presents an efficient method for cell encapsulation while preserving gel integrity, expanding the applicability of colloidal hydrogels for tissue engineering and bioprinting. Overall, our study contributes to the design of improved cell delivery systems and biofabrication techniques.

Advances in screening hyperthermic nanomedicines in 3D tumor models.

Hyperthermic nanomedicines are particularly relevant for tackling human cancer, providing a valuable alternative to conventional therapeutics. The early-stage preclinical performance evaluation of such anti-cancer treatments is conventionally performed in flat 2D cell cultures that do not mimic the volumetric heat transfer occurring in human tumors. Recently, improvements in bioengineered 3D in vitro models have unlocked the opportunity to recapitulate major tumor microenvironment hallmarks and generate highly informative readouts that can contribute to accelerating the discovery and validation of efficient hyperthermic treatments. Leveraging on this, herein we aim to showcase the potential of engineered physiomimetic 3D tumor models for evaluating the preclinical efficacy of hyperthermic nanomedicines, featuring the main advantages and design considerations under diverse testing scenarios. The most recent applications of 3D tumor models for screening photo- and/or magnetic nanomedicines will be discussed, either as standalone systems or in combinatorial approaches with other anti-cancer therapeutics. We envision that breakthroughs toward developing multi-functional 3D platforms for hyperthermia onset and follow-up will contribute to a more expedited discovery of top-performing hyperthermic therapies in a preclinical setting before their in vivo screening.

Novel Insights on the Role of Epigenetics in Androgen Receptor's Expression in Prostate Cancer.

The androgens/androgen receptor (AR) axis is the main therapeutic target in prostate cancer (PCa). However, while initially responsive, a subset of tumors loses AR expression through mechanisms putatively associated with epigenetic modifications. In this study, we assessed the link between the presence of CpG methylation in the 5'UTR and promoter regions of AR and loss of AR expression. Hence, we characterized and compared the methylation signature at CpG resolution of these regulatory regions in vitro, both at basal levels and following treatment with 5-aza-2-deoxycytidine (DAC) alone, or in combination with Trichostatin A (TSA). Our results showed heterogeneity in the methylation signature of AR negative cell lines and pinpointed the proximal promoter region as the most consistently methylated site in DU-145. Furthermore, this region was extremely resistant to the demethylating effects of DAC and was only significantly demethylated upon concomitant treatment with TSA. Nevertheless, no AR re-expression was detected at the mRNA or protein level. Importantly, after treatment, there was a significant increase in repressive histone marks at AR region 1 in DU-145 cells. Altogether, our data indicate that AR region 1 genomic availability is crucial for AR expression and that the inhibition of histone methyltransferases might hold promise for AR re-expression.

Supramolecular presentation of bioinstructive peptides on soft multilayered nanobiomaterials stimulates neurite outgrowth.

Peptide amphiphiles (PAs) have emerged as effective molecular building blocks for creating self-assembling nanobiomaterials for multiple biomedical applications. Herein, we report a straightforward approach to assemble soft bioinstructive platforms to recreate the native neural extracellular matrix (ECM) aiming for neuronal regeneration based on the electrostatic-driven supramolecular presentation of laminin-derived IKVAV-containing self-assembling PA (IKVAV-PA) on biocompatible multilayered nanoassemblies. Spectroscopic and microscopic techniques show that the co-assembly of positively charged low-molecular-weight IKVAV-PA with oppositely charged high-molecular-weight hyaluronic acid (HA) triggers the formation of ordered ß-sheet structures denoting a one-dimensional nanofibrous network. The successful functionalization of poly(L-lysine)/HA layer-by-layer nanofilms with an outer positively charged layer of self-assembling IKVAV-PA is demonstrated by the quartz crystal microbalance with dissipation monitoring and the nanofibrous morphological properties revealed by atomic force microscopy. The bioactive ECM-mimetic supramolecular nanofilms promote the enhancement of primary neuronal cells' adhesion, viability, and morphology when compared to the PA without the IKVAV sequence and PA-free biopolymeric multilayered nanofilms, and stimulate neurite outgrowth. The nanofilms hold great promise as bioinstructive platforms for enabling the assembly of customized and robust multicomponent supramolecular biomaterials for neural tissue regeneration.

Mammary Glands of Women, Female Dogs and Female Rats: Similarities and Differences to Be Considered in Breast Cancer Research.

Breast cancer is one of the most common and well-known types of cancer among women worldwide and is the most frequent neoplasm in intact female dogs. Female dogs are considered attractive models or studying spontaneous breast cancer, whereas female rats are currently the most widely used animal models for breast cancer research in the laboratory context. Both female dogs and female rats have contributed to the advancement of scientific knowledge in this field, and, in a "One Health" approach, they have allowed broad understanding of specific biopathological pathways, influence of environmental factors and screening/discovery of candidate therapies. This review aims to clearly showcase the similarities and differences among woman, female dog and female rat concerning to anatomical, physiological and histological features of the mammary gland and breast/mammary cancer epidemiology, in order to better portray breast tumorigenesis, and to ensure appropriate conclusions and extrapolation of results among species. We also discuss the major aspects that stand out in these species. The mammary glands of female dogs and women share structural similarities, especially with respect to the lactiferous ducts and lymphatic drainage. In contrast, female rats have only one lactiferous duct per nipple. A comprehensive comparison between humans and dogs is given a special focus, as these species share several aspects in terms of breast/mammary cancer epidemiology, such as age of onset, hormonal etiology, risk factors, and the clinical course of the disease. Holistically, it is clear that each species has advantages and limitations that researchers must consider during the development of experimental designs and data analysis.

Self-Assembly of Platelet Lysates Proteins into Microparticles by Unnatural Disulfide Bonds for Bottom-Up Tissue Engineering.

There is a demand to design microparticles holding surface topography while presenting inherent bioactive cues for applications in the biomedical and biotechnological fields. Using the pool of proteins present in human-derived platelet lysates (PLs), the production of protein-based microparticles via a simple and cost-effective method is reported, exploring the prone redox behavior of cysteine (Cy-SH) amino acid residues. The forced formation of new intermolecular disulfide bonds results in the precipitation of the proteins as spherical, pompom-like microparticles with adjustable sizes (15-50 µm in diameter) and surface topography consisting of grooves and ridges. These PL microparticles exhibit extraordinary cytocompatibility, allowing cell-guided microaggregates to form, while also working as injectable systems for cell support. Early studies also suggest that the surface topography provided by these PL microparticles can support osteogenic behavior. Consequently, these PL microparticles may find use to create live tissues via bottom-up procedures or injectable tissue-defect fillers, particularly for bone regeneration, with the prospect of working under xeno-free conditions.

Viscous Microcapsules as Microbioreactors to Study Mesenchymal Stem/Stromal Cells Osteolineage Commitment.

It is essential to design a multifunctional well-controlled platform to transfer mechanical cues to the cells in different magnitudes. This study introduces a platform, a miniaturized bioreactor, which enables to study the effect of shear stress in microsized compartmentalized structures. In this system, the well-established cell encapsulation system of liquefied capsules (LCs) is used as microbioreactors in which the encapsulated cells are exposed to variable core viscosities to experience different mechanical forces under a 3D dynamic culture. The LC technology is joined with electrospraying to produce such microbioreactors at high rates, thus allowing the application of microcapsules for high-throughput screening. Using this platform for osteogenic differentiation as an example, shows that microbioreactors with higher core viscosity which produce higher shear stress lead to significantly higher osteogenic characteristics. Moreover, in this system the forces experienced by cells in each LC are simulated by computational modeling. The maximum wall shear stress applied to the cells inside the bioreactor with low, and high core viscosity environment is estimated to be 297 and 1367 mPa, respectively, for the experimental setup employed. This work outlines the potential of LC microbioreactors as a reliable in vitro customizable platform with a wide range of applications.