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As the essential foundation of bioprinting technology, cell-laden bio-ink is confronted with the inevitable contradiction between printability and bioactivity. For example, type I collagen has been widely applied for its excellent biocompatibility; however, its relatively low self-assembly speed restricts the performance in high-precision bioprinting of cell-laden structures. In this study, we synthesize norbornene-functionalized neutral soluble collagen (NorCol) by the reaction of acid-soluble collagen (Col) and carbic anhydride in the aqueous phase. NorCol retains collagen triple-helical conformation and can be quickly orthogonally cross-linked to build a cell-laden hydrogel via a cell-friendly thiol-ene photoclick reaction. Moreover, the additional carboxyl groups produced in the reaction of carbic anhydride and collagen obviously improve the solubility of NorCol in neutral buffer and miscibility of NorCol with other polymers such as alginate and gelatin. It enables hybrid bio-ink to respond to multiple stimuli, resulting in continuous cross-linked NorCol networks in hybrid hydrogels. For the first time, the collagen with a triple helix structure and gelatin can be mixed and printed, keeping the integrity of the printed construct after gelatin’s dissolution. The molecular interaction among giant collagen molecules allows NorCol hydrogel formation at a low concentration, which leads to excellent cell spreading, migration, and proliferation. These properties give NorCol flexible formability and excellent biocompatibility in temperature-, ion-, and photo-based bioprinting. We speculate that NorCol is a promising bio-ink for emerging demands in tissue engineering, regenerative medicine, and personalized therapeutics.

Multi-angle remote sensing images are acquired over the same imaging scene from different angles, and share similar but not identical information. It is therefore possible to enhance the spatial resolution of the multi-angle remote sensing images by the super-resolution reconstruction technique. However, different sensor shooting angles lead to different resolutions for each angle image, which affects the effectiveness of the super-resolution reconstruction of the multi-angle images. In view of this, we propose utilizing adaptive weighted super-resolution reconstruction to alleviate the limitations of the different resolutions. This paper employs two adaptive weighting themes. The first approach uses the angle between the imaging angle of the current image and that of the nadir image. The second is closely related to the residual error of each low-resolution angle image. The experimental results confirm the feasibility of the proposed method and demonstrate the effectiveness of the proposed adaptive weighted super-resolution approach.

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