Precision oncology continues to challenge the "one-size-fits-all" dogma. Under the precision oncology banner, cancer patients are screened for molecular tumor alterations that predict treatment response, ideally leading to optimal treatments. Functional assays that directly evaluate treatment efficacy on the patient's cells offer an alternative and complementary tool to improve the accuracy of precision oncology. Unfortunately, traditional Petri dish-based assays overlook much tumor complexity, limiting their potential as predictive functional biomarkers. Here, we review past applications of microfluidic systems for precision medicine and discuss the present and potential future role of functional microfluidic assays as treatment predictors. 

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A role for microfluidic systems in precision medicine

Developing effective stem cell based therapies requires the design of complex in vitro culture systems for more accurate representation of the stem cell niche. Attempts to improve conventional cell culture platforms include the use of biomaterial coated culture plates, sphere culture, microfluidic systems and bioreactors. Most of these platforms are not cost-effective, require industrial technical expertise to fabricate, and remain too simplistic compared to the physiological cell niche. The human amniotic membrane (hAM) has been used successfully in clinical grafting applications due to its unique biological composition and regenerative properties. In this study, we present a combinatorial platform that integrates the hAM with biomolecular, topographic and mechanical cues in one versatile model. Methods We utilized the hAM to provide the biological and the three dimensional (3D) topographic components of the prototype. The 3D nano-roughness of the hAM was characterized using surface electron microscopy and surface image analysis (ImageJ and SurfaceJ). We developed additional macro-scale and micro-scale versions of the platform which provided additional shear stress factors to simulate the fluid dynamics of the in vivo extracellular fluids. Results Three models of varying complexities of the prototype were assembled. A well-defined 3D surface modulation of the hAM in comparable to commercial 3D biomaterial culture substrates was achieved without complex fabrication and with significantly lower cost. Performance of the prototype was demonstrated through culture of primary human umbilical cord mononuclear blood cells (MNCs), human bone marrow mesenchymal stem cell line (hBMSC), and human breast cancer tissue. Conclusion This study presents methods of assembling an integrated, flexible and low cost biomimetic cell culture platform for diverse cell culture applications.

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A Cost-Effective Method to Assemble Biomimetic 3D Cell Culture Platforms.

Effect of metal mesh addition on polymer surface etching by an atmospheric pressure plasma jet

Microfabrication and microfluidics contribute to the research of cellular functions of cells and their interaction with their environment. Previously, it has been shown that microfluidics can contribute to the isolation, selection, characterization and migration of cells. This review aims to provide stem cell researchers with a toolkit of microtechnology (mT) instruments for elucidating complex stem cells functions which are challenging to decipher with traditional assays and animal models. These microdevices are able to investigate about the differentiation and niche interaction, stem cells transcriptomics, therapeutic functions and the capture of their secreted microvesicles. In conclusion, microtechnology will allow a more realistic assessment of stem cells properties, driving and accelerating the translation of regenerative medicine approaches to the clinic.

Microtechnology applied to stem cells research and development.

The application of stem cell-based therapeutics in improving human health is the ultimate anticipated outcome of stem cell research. Yet there exists a recognized lag between laboratory discoveries confirming the potential of stem cells and their actual application in routine clinical care. This lag can be appreciated if we contrast the number of research articles published in the field of stem cells with the number of products used in clinical practice. For example, a search for the keyword “stem cell” found 279,213 publications on PubMed, whereas only five products, all based on hematopoietic stem cells, were approved for therapeutic use by the US Food and Drug Administration [1]. This chapter will provide an overview of emerging technologies applied to help overcome such challenges with a highlight on their potential for clinical applications.

Advances in Micro- and Nanotechnologies for Stem Cell-Based Translational Applications

The advancement of sample preparation techniques is essential for the field of cell-based therapeutics. To obtain cells suited for clinical applications, the entire process starting from acquiring donor tissue biopsy, all through cell transplantation into the recipient, should occur in an integrated, safe, and efficient system. The current laboratory approach for solid tissue-to-cell isolation is invasive and involves multiple incoherent manual procedures running in an open operator-dependent system. Such an approach provides a chain of events for systematic cell loss that would be unfavorable for rare cell populations such as adult and cancer stem cells. A few lab-on-chip platforms were proposed to process biological tissues, however, they were limited to partial tissue dissociation and required additional processing off-chip. Here, we report the first microfluidic platform that can dissociate native biological tissue into ready-to-use single cells. The platform can merge the successive steps of tissue dissociation, debris filtration, cell sieving, washing, and staining in one streamlined process. Performance of the platform was tested with diverse biological tissues and it could yield viable cells that were ready for on or off-chip cell culture without further processing. Microfluidic tissue dissociation using this platform produced a higher number of viable single cells (an average of 2262 cells/ml per milligram of tissue compared to 1233.25 cells/ml/mg with conventional dissociation).

A microfluidic platform for dissociating clinical scale tissue samples into single cells

Endometrial stem cells provide a readily accessible source of adult stem cells suitable for various stem cell based therapies. The first essential step in the process of stem cell isolation, sorting and culture is tissue dissociation into single cell suspension. Tissue dissociation efficiency determines the number of resulting viable cells which in turn could affect the feasibility of the subsequent stem cell application. Microfluidic based platforms could provide several advantages over current conventional tissue dissociation techniques (e.g. mechanical or enzymatic or both) and help the optimization of the process towards a better reproducible cellular outcome. Objective: To develop a simple miniaturized platform for endometrial tissue dissociation which can be used to evaluate and optimize experimental conditions necessary for producing single cell suspension with minimal cell damage. Methods: A Poly-DiMethylSiloxane (PDMS) channel microfluidic platform was designed. The platform includes a tissue dissociation chamber where raw endometrial tissue was incubated. Trypsin was delivered through an inlet channel while another inlet enabled parallel delivery of a cell suspension medium and an outlet channel received the downstream dissociated endometrial cells. A cell size based filtration step is designed to trap large debris using two rows of posts. A viability stain is used to test the viability of cells produced at different enzyme-tissue contact durations. Conclusion: We present a simple microfluidics based platform for endometrial tissue dissociation that can be used for subsequent endometrial stem cell research applications and can be further applied to other tissues.

Omnia Ahmed

Papers

A microfluidic platform for dissociating clinical scale tissue samples into single cells

Tissue dissociation miniaturized platform for uterine stem cell isolation and culture