Mammalian cells are sensitive to the physical properties of their micro-environment such as the stiffness and geometry of the substrate. It is known that the stiffness of the substrate plays a key role in the process of mammalian myogenesis. However, the effect of geometrical constraints on the process of myogenic differentiation needs to be explored further. Here, we show that the geometrical cues of substrates can significantly influence the differentiation process of C2C12 skeletal myoblasts. Three different geometries including lines of different widths, tori of different inner diameters, and hybrid structures (linear and circular features with different arc degrees) were created by micro-contact printing of fibronectin on the surface of Petri dishes. The differentiation of C2C12 cells was studied over a period of seven days and was quantified; we report the differentiation parameters of (1) fusion index, (2) degree of maturation, (3) alignment, and (4) response to electrical pulse stimulation (EPS). Hybrid structures with the smallest arc degree (hybrid 30°) showed the best results for all four differentiation parameters. The hybrid 30° pattern exhibits an ~2-fold increase in the fusion index when compared to the line patterns and an ~3-fold increase when compared to the toroid patterns. The hybrid 30° also showed a higher maturation index compared to the line or the toroid patterns. In response to electrical stimulation (20 V, 50 ms pulse, 1 Hz), mature myotubes on hybrid 30° patterns showed an ~2-fold increase in cellular displacement when compared to myotubes on the line and torus patterns. We tested the influence of C2C12 cell density on fusion and maturation indices, and the results suggest that density does not exert significant influence on cellular differentiation under these conditions. Our results can have important implications in engineering skeletal muscle tissues and designing muscle cell bio-actuators.

Liquid biopsy is a technique that utilizes circulating biomarkers in the body fluids of cancer patients to provide information regarding the genetic landscape of the cancer. It is emerging as an alternative and complementary diagnostic and prognostic tool to surgical biopsy in oncology. Liquid biopsy focuses on the detection and isolation of circulating tumor cells, circulating tumor DNA and exosomes, as a source of genomic and proteomic information in cancer patients. Liquid biopsy is expected to provide the necessary acceleratory force for the implementation of precision oncology in clinical settings by contributing an enhanced understanding of tumor heterogeneity and permitting the dynamic monitoring of treatment responses and genomic variations. However, widespread implementation of liquid biopsy based biomarker-driven therapy in the clinical practice is still in its infancy. Technological advancements have resolved many of the hurdles faced in the liquid biopsy methodologies but sufficient clinical and technical validation for specificity and sensitivity has not yet been attained for routine clinical implementation. This article provides a comprehensive review of the clinical utility of liquid biopsy and its effectiveness as an important diagnostic and prognostic tool in colorectal, breast, hepatocellular, gastric and lung carcinomas which were the five leading cancer related mortalities in 2018.

Nanobiosensors based on silicon nanowire field effect transistors offer advantages of low cost, label-free detection, and potential for massive parallelization. As a result, these sensors have often been suggested as an attractive option for applications in point-of-care (POC) medical diagnostics. Unfortunately, a number of performance issues, such as gate leakage and current instability due to fluid contact, have prevented widespread adoption of the technology for routine use. High-k dielectrics, such as hafnium oxide (HfO2), have the known ability to address these challenges by passivating the exposed surfaces against destabilizing concerns of ion transport. With these fundamental stability issues addressed, a promising target for POC diagnostics and SiNWFETs has been small oligonucleotides, more specifically, microRNA (miRNA). MicroRNAs are small RNA oligonucleotides which bind to mRNAs, causing translational repression of proteins, gene silencing, and expressions are typically altered in several forms of cancer. In this paper, we describe a process for fabricating stable HfO2 dielectric-based silicon nanowires for biosensing applications. Here we demonstrate sensing of single-stranded DNA analogues to their microRNA cousins using miR-10b and miR-21 as templates, both known to be upregulated in breast cancer. We characterize the effect of surface functionalization on device performance using the miR-10b DNA analogue as the target sequence and different molecular weight poly-l-lysine as the functionalization layer. By optimizing the surface functionalization and fabrication protocol, we were able to achieve <100 fM detection levels of the miR-10b DNA analogue, with a theoretical limit of detection of 1 fM. Moreover, the noncomplementary DNA target strand, based on miR-21, showed very little response, indicating a highly sensitive and highly selective biosensing platform.

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