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An unconventional “heteromorphic” superlattice (HSL) is realized, comprised of repeated layers of different materials with differing morphologies: semiconducting pc-In2O3 layers interleaved with insulating a-MoO3 layers. Originally proposed by Tsu in 1989, yet never fully realized, the high quality of the HSL heterostructure demonstrated here validates the intuition of Tsu, whereby the flexibility of the bond angle in the amorphous phase and the passivation effect of the oxide at interfacial bonds serve to create smooth, high-mobility interfaces. The alternating amorphous layers prevent strain accumulation in the polycrystalline layers while suppressing defect propagation across the HSL. For the HSL with 7:7 nm layer thickness, the observed electron mobility of 71 cm2/Vs, matches that of the highest quality In2O3 thin films. The atomic structure and electronic properties of crystalline In2O3 / amorphous MoO3 interfaces are verified using ab-initio molecular dynamics simulations and hybrid functional calculations. This work generalizes the superlattice concept to an entirely new paradigm of morphological combinations. 

Abstract Additive manufacturing (AM) enables the tailored production of precision fibrous scaffolds toward various engineered tissue models. Moreover, by functionalizing scaffolds in either a uniform or gradient pattern of biomolecules, different target tissues can be fabricated in vitro to capture key characteristics of in vivo cellular microenvironments. However, current engineered tissue models lack the appropriate cellular cues that are needed to deterministically direct cell behavior. Specifically, tunable and reproducible scaffold‐guided stimuli are identified herein as the missing link between biomaterial structure and cellular behavior. Therefore, the bottleneck of precision control is addressed here over the immobilization of patterned biomolecular stimuli with either uniform or gradient distribution over the AM‐enabled 3D biomaterial model as a function of different growth factors exposure variables, protocols, and various scaffold architectural design parameters. The produced study outcomes herein will improve the directing and guiding of biological cell attachment and growth direction in the context of scaffold‐guided stimuli techniques. Therefore, unprecedented control is presented here over 3D structured biomaterial gradient functionalization and immobilization of biomolecules toward biomimetic tissue architectures. 

Melt electrohydrodynamic processes, in conjunction with a moveable collector, have promising engineered tissue applications. However, the residual charges within the fibers deteriorate its printing fidelity. To clarify the mechanism through which the residual charges play roles and exclude the confounding effects of collector movement, a stationary printing mode is adopted in which fibers deposit on a stationary collector. Effects of process parameters on generalizable printing outcomes are studied herein. The fiber deposit bears a unique shape signature typified by a central cone surrounded by an outer ring and is characterized by a ratio of its height and base diameter Hdep/Ddep. Results indicate Hdep/Ddep increases with collector temperature and decreases slightly with voltage. Moreover, the steady-state dynamic jet deposition process is recorded and analyzed at different collector temperatures. A charge-based polarization mechanism describing the effect of collector temperature on the fiber accumulating shape is apparent in both initial and steady-state phases of fiber deposition. Therefore, a key outcome of this study is the identification and mechanistic understanding of collector temperature as a tunable process variable that can yield predictable structural outcomes. This may have cross-cutting potential for additive manufacturing process applications such as the melt electrowriting of layered scaffolds. 

Abstract Discovering natural product biosynthetic pathways of medicinal plants is challenging and laborious. Capturing the coregulation patterns of pathway enzymes, particularly transcriptomic regulation, has proven an effective method to accelerate pathway identification. In this study, we developed a yeast‐based screening method to capture the protein‐protein interactions (PPI) between plant enzymes, which is another useful pattern to complement the prevalent approach. Combining this method with plant multiomics analysis, we discovered four enzyme complexes and their organized pathways from kratom, an alkaloid‐producing plant. The four pathway branches involved six enzymes, including a strictosidine synthase, a strictosidine β‐D‐glucosidase (MsSGD), and four medium‐chain dehydrogenase/reductases (MsMDRs). PPI screening selected six MsMDRs interacting with MsSGD from 20 candidates predicted by multiomics analysis. Four of the six MsMDRs were then characterized as functional, indicating the high selectivity of the PPI screening method. This study highlights the opportunity of leveraging post‐translational regulation features to discover novel plant natural product biosynthetic pathways. 

Abstract The printing accuracy of the melt electrowriting (MEW) process is adversely affected by residual charge entrapped within the printed fibers. To mitigate this effect, the residual charge amount (Q_r) must first be accurately determined. In this study,Q_ris measured by a commercial electrometer at a nanocoulomb scale for MEW‐enabled scaffolds. Based on this enabling measurement, the effects of various design parameters (including substrate surface conductivityσ, printing timet, layer numberN), and process parameters (including voltageU, translational stage speedv, and material temperatureT_m), onQ_rare investigated. An increase ofσor decrease ofNhelps to decreaseQ_r. The effects of different process parameters on the residual charge can be either dependent or independent of fiber morphologies. Moreover, the fiber‐morphology dependent and independent effect can be either synergistic (UandT_m) or antagonistic (e.g.,v) for different process parameters. Under same conditions,Q_rin the interweaving scaffold design is generally smaller than that in the non‐interweaving scaffold design. These results help to furnish necessary insights into the charge dissipation process for a melt‐based electrohydrodynamic printing process while providing a systematic methodology to mitigate the residual charge accumulation.