Abstract 109: The Effect Of Cell Sex On Cardiogenic Differentiation Of Human Induced Pluripotent Stem Cells And Their Maturation Processes

Introduction: Patient-specific human induced pluripotent stem cells (hiPSC)-derived cardiomyocytes (CMs) are increasingly used for in vitro disease modeling and drug screening, as well in vivo regenerative therapies. The cardiac differentiation efficacy of hiPSCs, together with the maturation level of generated CMs, are critical factors in achieving the required numbers of functional patient-specific cardiac muscle cells for clinical applications. Although extensive studies have improved the efficacy of differentiation and maturation processes, the role of cell sex in these processes has not been fully investigated. Hypothesis: Cell sex affects i) the cardiogenic differentiation efficacy of hiPSCs; and ii) maturation processes of hiPSC-CMs. Methods and Results: We have successfully and reproducibly fabricated patterned substrates recapitulating the 3D shape of mature CMs, using photolithography approaches, and demonstrated that the substrate could i) accelerate the differentiation of hiPSCs to CMs, and ii) facilitate maturation and functionality of immature hiPSC-CMs. Male and female hiPSCs, derived from human amniotic mesenchymal stem cells of male and female fetuses, were cultured onto flat (control) vs. patterned substrates. A total of 400 differentiation assays were conducted, 200 per each cell sex, on the flat ( n = 100) and patterned ( n = 100) substrates. A chemically defined approach was used to differentiate the cells toward CMs. On the flat (conventional) substrates, 59% of batches of male and 87% of batches of female hiPSCs differentiated into beating CMs (> 80%). On the patterned substrates, these numbers changed to 83% and 94% of successful differentiations for male and female hiPSCs, respectively. These results indicate the significant effect of substrate-mediated topographical cues on the cardiac differentiation yield of stem cells and the batch-to-batch variation. On both substrate types, female cells demonstrated significantly higher success rates of cardiac differentiation compared to the male cells. In addition, the CMs produced on the patterned substrates demonstrated higher purity than those created on the flat substrates both for male and female cells. Quantitative polymerase chain reaction (qPCR) was used to probe the male and female cell differences in expression of genes related to cardiac maturity, contractility, and Ca 2+ transport (TNNT2, MYH6, MYH7, and CACNA1c) and the outcomes revealed substantially greater expression levels of the maturation genes in differentiated female CMs cultured on the patterned substrates compared to the male cells. Conclusions: These results indicate that male and female hiPSCs and hiPSC-CMs respond differently to the identical substrates in terms of their differentiation and maturation efficacies.

Polarization-insensitive GaN metalenses at visible wavelengths

The growth of wide-bandgap materials on patterned substrates has revolutionized the means with which we can improve the light output power of gallium nitride (GaN) light-emitting diodes (LEDs). Conventional patterned structure inspection usually relies on an expensive vacuum-system-required scanning electron microscope (SEM) or optical microscope (OM) with bulky objectives. On the other hand, ultra-thin metasurfaces have been widely used in widespread applications, especially for converging lenses. In this study, we propose newly developed, highly efficient hexagon-resonated elements (HREs) combined with gingerly selected subwavelength periods of the elements for the construction of polarization-insensitive metalenses of high performance. Also, the well-developed fabrication techniques have been employed to realize the high-aspect-ratio metalenses working at three distinct wavelengths of 405, 532, and 633 nm with respective diffraction-limited focusing efficiencies of 93%, 86%, and 92%. The 1951 United States Air Force (USAF) test chart has been chosen to characterize the imaging capability. All of the images formed by the 405-nm-designed metalens show exceptional clear line features, and the smallest resolvable features are lines with widths of 870 nm. To perform the inspection capacity for patterned substrates, for the proof of concept, a commercially available patterned sapphire substrate (PSS) for the growth of the GaN LEDs has been opted and carefully examined by the high-resolution SEM system. With the appropriately chosen metalenses at the desired wavelength, the summits of structures in the PSS can be clearly observed in the images. The PSS imaging qualities taken by the ultra-thin and light-weight metalenses with a numerical aperture (NA) of 0.3 are comparable to those seen by an objective with the NA of 0.4. This work can pioneer semiconductor manufacturing to choose the polarization-insensitive GaN metalenses to inspect the patterned structures instead of using the SEM or the bulky and heavy conventional objectives.

Contact guidance as a consequence of coupled morphological evolution and motility of adherent cells

Adherent cells seeded on substrates spread and evolve their morphology while simultaneously displaying motility. Phenomena such as contact guidance viz. the alignment of cells on patterned substrates, are strongly linked to the coupling of morphological evolution with motility. Here we employ a recently developed statistical thermodynamics framework for modelling the non-thermal fluctuating response of the cells to probe this coupling. This thermodynamic framework is first extended to predict temporal responses via a Langevin style model. The Langevin model is then shown to not only predict the different experimentally observed temporal scales for morphological observables such as cell area and elongation but also the interplay of morphology with motility that ultimately leads to contact guidance.

Correction: Observation of ordered arrays of endotaxially grown nanostructures from size-selected Cu-nanoclusters deposited on patterned substrates of Si

Correction for ‘Observation of ordered arrays of endotaxially grown nanostructures from size-selected Cu-nanoclusters deposited on patterned substrates of Si’ by Shyamal Mondal et al., Phys. Chem. Chem. Phys., 2021, 23, 6009–6016 DOI: 10.1039/D0CP06089E.

Observation of ordered arrays of endotaxially grown nanostructures from size-selected Cu-nanoclusters deposited on patterned substrates of Si

We report on the first time observation of endotaxial growth of size-selected nanoclusters on a patterned substrate when we fabricate highly ordered and partially embedded 3D crystalline Cu nanostructure arrays...