Mariana Carvalho

Evaluating Biomaterial- and Microfluidic-Based 3D Tumor Models

Cancer is a major cause of morbidity and mortality worldwide, with a disease burden estimated to increase over the coming decades. Disease heterogeneity and limited information on cancer biology and disease mechanisms are aspects that 2D cell cultures fail to address. Here, we review the current ‘state-of-the-art’ in 3D tissue-engineering (TE) models developed for, and used in, cancer research. We assess the potential for scaffold-based TE models and microfluidics to fill the gap between 2D models and clinical application. We also discuss recent advances in combining the principles of 3D TE models and microfluidics, with a special focus on biomaterials and the most promising chip-based 3D models.

Gellan gum-coated gold nanorods: an intracellular nanosystem for bone tissue engineering

Gold nanorods (AuNRs) have emerged as an exceptional nanotool for a myriad of applications ranging from cancer therapy to tissue engineering. However, their surface modification with biocompatible and stabilizing biomaterials is crucial to allow their use in a biological environment. Herein, low-acyl gellan gum (GG) was used to coat AuNRs surface, taking advantage of its stabilizing, biocompatible and gelling features. The layer-by-layer based strategy implied the successive deposition of poly(acrylic acid), poly(allylamine hydrochloride) and GG, which allowed the formation of a GG hydrogel-like shell with 7 nm thickness around individual AuNRs. Stability studies in a wide range of pH and salt concentrations showed that the polysaccharide coating can prevent AuNRs aggregation. Moreover, a reversible pH-responsive feature of the nanoparticles was observed. Cytocompatibility and osteogenic ability of GG-coated AuNRs were also addressed. After 14 days of culturing within SaOS-2, an osteoblast-like cell line, in vitro studies revealed that AuNRs-GG exhibit no cytotoxicity, were internalized by the cells and localized inside lysosomes. AuNRs-GG combined with osteogenic media enhanced by two fold the mineralization capacity, as compared to cells exposed to osteogenic media alone. The proposed system has shown interesting features for osteogenesis, and further insights might be relevant for drug delivery, tissue engineering and regenerative medicine.

Anti-cancer drug validation: the contribution of tissue engineered models

Drug toxicity frequently goes concealed until clinical trials stage, which is the most challenging, dangerous and expensive stage of drug development. Both the cultures of cancer cells in traditional 2D assays and animal studies have limitations that cannot ever be unraveled by improvements in drug-testing protocols. A new generation of bioengineered tumors is now emerging in response to these limitations, with potential to transform drug screening by providing predictive models of tumors within their tissue context, for studies of drug safety and efficacy. Considering the NCI60, a panel of 60 cancer cell lines representative of 9 different cancer types: leukemia, lung, colorectal, central nervous system (CNS), melanoma, ovarian, renal, prostate and breast, we propose to review current “state of art” on the 9 cancer types specifically addressing the 3D tissue models that have been developed and used in drug discovery processes as an alternative to complement their study.

Mimicking the 3D biology of osteochondral tissue with microfluidic-based solutions: breakthroughs towards boosting drug testing and discovery

The development of tissue-engineering (TE) solutions for osteochondral (OC) regeneration has been slowed by technical hurdles related to the recapitulation of their complex and hierarchical architecture. OC defects refer to damage of both the articular cartilage and the underlying subchondral bone. To repair an OC tissue defect, the complexity of the bone and cartilage must be considered. To help achieve this, microfluidics is converging with TE approaches to provide new treatment possibilities. Microfluidics uses precise micrometer-to-millimeter-scale fluid flows to achieve high-resolution and spatial and/or temporal control of the cell microenvironment, providing powerful tools for cell culturing. Herein, we overview the progress of microfluidics for developing 3D in vitro models of OC tissue, with a focus on cancer bone metastasis.

A semiautomated microfluidic platform for real-time investigation of nanoparticles’ cellular uptake and cancer cells’ tracking

AIM Develop a platform composed of labeled dendrimer nanoparticles (NPs) and a microfluidic device for real-time monitoring of cancer cells fate. MATERIALS & METHODS Carboxymethylchitosan/poly(amidoamine) dendrimer NPs were labeled with fluorescein-5(6)-isothiocyanate and characterized using different physicochemical techniques. After, HeLa, HCT-116 and U87MG were cultured in the presence of NPs, and cell viability and internalization efficiency in static (standard culture) and dynamic (microfluidic culture) conditions were investigated. RESULTS Cancer cells cultured with NPs in dynamic conditions were viable and presented higher internalization levels as compared with static 2D cultures. CONCLUSION This work demonstrated that the proposed microfluidic-based platform allows real-time monitoring, which upon more studies, namely, the assessment of an anticancer drug release effect could be used for cancer theranostics.

Tuning Enzymatically Crosslinked Silk Fibroin Hydrogel Properties for the Development of a Colorectal Cancer Extravasation 3D Model on a Chip

Abstract Microfluidic devices are now the most promising tool to mimic in vivo like scenarios such as tumorigenesis and metastasis due to its ability to more closely mimic cells natural microenvironment (such as 3D environment and continuous perfusion of nutrients). In this study, the ability of 2% and 3% enzymatically crosslinked silk fibroin hydrogels with different mechanical properties are tested in terms of colorectal cancer cell migration, under different microenvironments in a 3D dynamic model. Matrigel is used as control. Moreover, a comprehensive comparison between the traditional Boyden chamber assay and the 3D dynamic microfluidic model in terms of colorectal cancer cell migration is presented. The results show profound differences between the two used biomaterials and the two migration models, which are explored in terms of mechanical properties of the hydrogels as well as the intrinsic characteristics of the models. Moreover, the developed 3D dynamic model is validated by demonstrating that hVCAM‐1 plays a major role in the extravasation process, influencing extravasation rate and traveled distance. Furthermore, the developed model enables precise visualization of cancer cell migration within a 3D matrix in response to microenvironmental cues, shedding light on the importance of biophysical properties in cell behavior.

Tissue engineering strategies for osteochondral repair

Tissue engineering strategies have been pushing forward several fields in the range of biomedical research. The musculoskeletal field is not an exception. In fact, tissue engineering has been a great asset in the development of new treatments for osteochondral lesions. Herein, we overview the recent developments in osteochondral tissue engineering. Currently, the treatments applied in a clinical scenario have shown some drawbacks given the difficulty in regenerating a fully functional hyaline cartilage. Among the different strategies designed for osteochondral regeneration, it is possible to identify cell-free strategies, scaffold-free strategies, and advanced strategies, where different materials are combined with cells. Cell-free strategies consist in the development of scaffolds in the attempt to better fulfill the requirements of the cartilage regeneration process. For that, different structures have been designed, from monolayers to multilayered structures, with the intent to mimic the osteochondral architecture. In the case of scaffold-free strategies, they took advantage on the extracellular matrix produced by cells. The last strategy relies in the development of new biomaterials capable of mimicking the extracellular matrix. This way, the cell growth, proliferation, and differentiation at the lesion site are expedited, exploiting the self-regenerative potential of cells and its interaction with biomolecules. Overall, despite the difficulties associated with each approach, tissue engineering has been proven a valuable tool in the regeneration of osteochondral lesions and together with the latest advances in the field, promises to revolutionize personalized therapies.

Inception and specification of what-if scenarios using OLAP usage preferences

The possibility to simulate hypothetical scenarios without harming the business using What-If analysis tools and to retrieve highly refined information is an interesting way of achieving such advantages. In a previous work, it was introduced a hybrid model that combines What-If analysis and OLAP usage preferences, which helps filtering the information, meeting the users’ needs and business requirements without losing data quality. In addition, it helps to overcome the lack of a user expertise using What-If analysis process. In this paper, we propose a formal verification of a hybridization model, integrating What-If analysis scenarios with OLAP usage preferences, which aim to suggest to the user enriched What-If scenarios based on the usage preferences of a specific user. For this, we used Alloy to specify and verify the referred model, which enables to analyze and verify our hybrid model, discovering possible ambiguity and inconsistencies.

Using Alloy for Verifying the Integration of OLAP Preferences in a Hybrid What-If Scenario Application

Owning the right and high quality set of information is a crucial factor for developing business activities and consequently gaining competitive advantages. However, retrieving information is not enough. The possibility to simulate hypothetical scenarios without harming the business using What-If analysis tools and to retrieve highly refined information is an interesting way of achieving such advantages. Based on this, we designed and developed a specific piece of software especially oriented for discovering the best recommendations for What-If analysis scenarios’ parameters, using OLAP usage preferences. In this paper, we propose a formal description and verification of one of the phases of the hybridization model we developed related to the extraction of OLAP usage preferences. We used Alloy to specify and verify the viability of the process, and discover possible ambiguity and inconsistencies cases.

Conceiving hybrid what-if scenarios based on usage preferences

Nowadays, enterprise managers involved with decision-making processes struggle with numerous problems related to market position or business reputation of their companies. Owning the right and high quality set of information is a crucial factor for developing business activities and gaining competitive advantages on business arenas. However, today retrieving information is not enough anymore. The possibility to simulate hypothetical scenarios without harming the business using What-If analysis tools and to retrieve highly refined information is an interesting way for achieving such business advantages. In a previous work, we introduced a hybridization model that combines What-If analysis and OLAP usage preferences, which helps filter the information and meet the users’ needs and business requirements without losing data quality. The main advantage is to provide the user with a way to overcome the difficulties that arise when dealing with the conventional What-If analysis scenario process. In this paper, we show an application of this methodology using a sample database, and compare the results of a conventional What-if process and our methodology. We designed and developed a specific piece of software, which aims to discover the best recommendations for What-If analysis scenarios’ parameters using OLAP usage preferences, which incorporates user experience in the definition and analysis of a target decision-making scenario.