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A bifocal interference confocal microscopy system (BICMS) is proposed in which bifocal lenses are used to overcome the tradeoff between high resolution and long working distance, which cannot be achieved simultaneously in devices with small numerical apertures (NAs). In this work, a bifocal lens is introduced in the proposed system to ensure signals (generating the interference) originate from the same point on the surface of the object to be measured. The annular interference region generated by the bifocal lenses can be used to sharpen the width of the central bright spot. This reduces the full width at half maximum for the normalized lateral intensity point spread function, thereby improving the stability, anti-disturbing capabilities, and lateral resolution. A theoretical analysis (using a wavelength of 632.8 nm and an objective NA of 0.1) demonstrated BICMS improved the lateral resolution of the confocal microscope from 2.34 μ m to 1.33 μ m, which is 1.7 times that of a CMS; in the case of NA = 0.2, BICMS improved the lateral resolution of the confocal microscope from 1.24 μ m to 0.92 μ m, which is 1.3 times that of the CMS. As such, the proposed system is bringing the possibility of a wide range of applications for high-resolution confocal microimaging systems. [ABSTRACT FROM AUTHOR]

To overcome the limitations of phase sampling points in testing aspherical surface wavefronts using traditional interferometers, we propose a high-spatial-resolution method based on multi-directional orthogonal lateral shearing interferometry. In this study, we provide a detailed description of the methodology, which includes the theoretical foundations and experimental setup, along with the results from simulations and experiments. By establishing a relational model between the multi-directional differential wavefront and differential Zernike polynomials, we demonstrate high-spatial-resolution wavefront reconstruction using multi-directional orthogonal lateral shearing interferometry. Theoretical calculations and simulations of aspherical surface wavefront testing are followed by experimental verification on an aspherical surface with a known asphericity. Comparing the measurement results with those from the LuphoScan profilometer, we achieve a relative measurement error with an RMS precision better than λ/100. [ABSTRACT FROM AUTHOR]

To research the paracrine role of adipose tissue-derived mesenchymal stem cells (ADMSCs) in promoting angiogenesis under the three-dimensional culture conditions consisting of a functionalized self-assembling peptide nanofiber hydrogel. ADMSCs were isolated, extracted, and then identified. Three kinds of peptides (RADAI-16, RGD, and KLT) were prepared, and a functionalized self-assembling peptide nanofiber hydrogel was produced by mixing RADAI-16, RGD, and KLT in a volume ratio 2:1:1. AFM was used to observe RADAI-16, RGD, KLT, and the functionalized self-assembling peptide nanofiber hydrogel. Then, ADMSCs were cultured under three-dimensional conditions consisting of the peptide nanofiber hydrogel, and AFM was used to observe cell migration. The ADMSCs in the common culture group (37°C, 5% CO2 cell culture box) and hypoxic culture group (37°C, 10% CO2, and 1% O2 hypoxic culture box) acted as controls. ADMSCs were three-dimensionally cultured in situ for 1 day, and then the concentrations of HGF and VEGF in the supernatant were determined by ELISA. Cells were extracted from the peptide nanofiber hydrogel, and HO-1 expression was detected by western blotting. ADMSCs have high expression levels of CD29, CD90, and CDl05 and low expression levels of CD34 and CD45. In addition, they can differentiate into adipocytes and osteocytes. The diameters of the fibers of RADAI-16, RGD, KLT, and the functionalized self-assembling peptide hydrogel are 17.34 ± 1.82, 15.50 ± 1.41, 13.77 ± 1.18, and 20.26 ± 1.25 nm, respectively. AFM indicated that cells in the functionalized self-assembling peptide nanofiber hydrogel migrated farther than those in RADAI-16. The concentrations of HGF under common, hypoxic, and three-dimensional culture conditions were 47.31 ± 6.75, 247.86 ± 17.59, and 297.25 ± 17.95 pg/mL, respectively, while the concentrations of VEGF were 218.30 ± 3.03, 267.13 ± 4.27, and 289.14 ± 3.11 pg/mL, respectively. Both HGF and VEGF were expressed more in the presence of the functionalized self-assembling peptide nanofiber hydrogel than in its absence (P < 0.05). Using western blotting, ADMSCs cultured under hypoxic and three-dimensional conditions were found to have high expression levels of HO-1. Culturing ADMSCs under three-dimensional conditions consisting of functionalized self-assembling peptide nanofiber hydrogels can promote their paracrine role in angiogenesis, such as HGF and VEGF, and hypoxia is one of the important elements.