Sonochemical Degradation of Gelatin Methacryloyl to Control Viscoelasticity for Inkjet Bioprinting.

Inkjet printing enables the mimicry of the microenvironment of natural complex tissues by patterning cells and hydrogels at a high resolution. However, the polymer content of an inkjet-printable bioink is limited as it leads to strong viscoelasticity in the inkjet nozzle. Here it is demonstrated that sonochemical treatment controls the viscoelasticity of a gelatin methacryloyl (GelMA) based bioink by shortening the length of polymer chains without causing chemical destruction of the methacryloyl groups.

Dual-gate thin film transistor lactate sensors operating in the subthreshold regime.

Organic thin-film transistors (TFTs) with an electrochemically functionalized sensing gate are promising platforms for wearable health-monitoring technologies because they are light, flexible, and cheap. Achieving both high sensitivity and low power is highly demanding for portable or wearable devices. In this work, we present flexible printed dual-gate (DG) organic TFTs operating in the subthreshold regime with ultralow power and high sensitivity.

Transfer-Tattoo-Like Cell-Sheet Delivery Induced by Interfacial Cell Migration.

A direct transfer of a cell sheet from a culture surface to a target tissue is introduced. Commercially available, flexible parylene is used as the culture surface, and it is proposed that the UV-treated parylene offers adequate and intermediate levels of cell adhesiveness for both the stable cell attachment during culture and for the efficient cell transfer to a target surface. The versatility of this cell-transfer process is demonstrated with various cell types, including MRC-5, HDFn, HULEC-5a, MC3T3-E1, A549, C2C12 cells, and MDCK-II cells.

Effect of Aronia Extract on Collagen Synthesis in Human Skin Cell and Dermal Equivalent.

The regulation of collagen synthesis, which occurs in fibroblasts in the dermal layer, is a key process in dermis regeneration and skin reconstruction. Herein, we investigated whether extract affects the human skin condition. We focused on type I collagen synthesis using two different types of model systems: a monolayer of cells and a bioprinted 3D dermal equivalent.

Homogenization of a reaction diffusion equation can explain influenza A virus load data.

We study the influence of spatial heterogeneity on the antiviral activity of mouse embryonic fibroblasts (MEF) infected with influenza A. MEF of type Ube1L are composed of two distinct sub-populations, the strong type that sustains a strong viral infection and the weak type, sustaining a weak viral load. We present new data on the virus load infection of Ube1L, which have been micro-printed in a checker board pattern of different sizes of the inner squares.

All-Inkjet-Printed 3D Alveolar Barrier Model with Physiologically Relevant Microarchitecture.

With the outbreak of new respiratory viruses and high mortality rates of pulmonary diseases, physiologically relevant models of human respiratory system are urgently needed to study disease pathogenesis, drug efficacy, and pharmaceutics. In this paper, a 3D alveolar barrier model fabricated by printing four human alveolar cell lines, namely, type I and II alveolar cells (NCI-H1703 and NCI-H441), lung fibroblasts (MRC5), and lung microvascular endothelial cells (HULEC-5a) is presented. Automated high-resolution deposition of alveolar cells by drop-on-demand inkjet printing enables to fabricate a three-layered alveolar barrier model with an unprecedented thickness of ≈10 µm.

Author Correction: Freeform micropatterning of living cells into cell culture medium using direct inkjet printing.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Self-Organization of Fibroblast-Laden 3D Collagen Microstructures from Inkjet-Printed Cell Patterns.

One of the major challenges encountered in engineering complex tissues in vitro is to increase levels of complexity at the micron scale in 3D structures. Here, a strategy to create self-organized 3D collagen microstructures by 2D micropatterning of fibroblasts is developed. Drop-on-demand inkjet printing is used to pattern fibroblast cells on a collagen substrate in pre-designed patterns and with controlled density.

Inkjet-Spray Hybrid Printing for 3D Freeform Fabrication of Multilayered Hydrogel Structures.

Here, a new bioprinting process by combining drop-on-demand inkjet printing with a spray-coating technique, which enables the high-resolution, high-speed, and freeform fabrication of large-scale cell-laden hydrogel structures is reported. Hydrogel structures with various shapes and composed of different materials, including alginate, cellulose nanofiber, and fibrinogen, are fabricated using the inkjet-spray printing. To manufacture cell-friendly hydrogel structures with controllable stiffness, gelatine methacryloyl is saponified to stabilize jet formation and is subsequently mixed with sodium alginate to prepare blend inks.

Publisher Correction: Freeform micropatterning of living cells into cell culture medium using direct inkjet printing.

A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.

Freeform micropatterning of living cells into cell culture medium using direct inkjet printing.

Microfabrication methods have widely been used to control the local cellular environment on a micron scale. However, accurately mimicking the complexity of the in vivo tissue architecture while maintaining the freedom of form and design is still a challenge when co-culturing multiple types of cells on the same substrate. For the first time, we present a drop-on-demand inkjet printing method to directly pattern living cells into a cell-friendly liquid environment.

Drop-on-demand inkjet-based cell printing with 30-m nozzle diameter for cell-level accuracy.

We present drop-on-demand inkjet-based mammalian cell printing with a 30-m nozzle diameter for cell-level accuracy. High-speed imaging techniques have been used to analyze the go-and-stop movement of cells inside the nozzle under a pulsed pressure generated by a piezo-actuator and the jet formation after ejection. Patterning of an array of 20 × 20 dots on a glass substrate reveals that each printed drop contains 1.