Additive manufacturing, otherwise known as three-dimensional (3D) printing, is driving major innovations in many areas, such as engineering, manufacturing, art, education and medicine. Recent advances have enabled 3D printing of biocompatible materials, cells and supporting components into complex 3D functional living tissues. 3D bioprinting is being applied to regenerative medicine to address the need for tissues and organs suitable for transplantation. Compared with non-biological printing, 3D bioprinting involves additional complexities, such as the choice of materials, cell types, growth and differentiation factors, and technical challenges related to the sensitivities of living cells and the construction of tissues. Addressing these complexities requires the integration of technologies from the fields of engineering, biomaterials science, cell biology, physics and medicine. 3D bioprinting has already been used for the generation and transplantation of several tissues, including multilayered skin, bone, vascular grafts, tracheal splints, heart tissue and cartilaginous structures. Other applications include developing high-throughput 3D-bioprinted tissue models for research, drug discovery and toxicology.

3D bioprinting of tissues and organs

Nanocrystals (NCs) discussed in this Review are tiny crystals of metals, semiconductors, and magnetic material consisting of hundreds to a few thousand atoms each. Their size ranges from 2-3 to about 20 nm. What is special about this size regime that placed NCs among the hottest research topics of the last decades? The quantum mechanical coupling * To whom correspondence should be addressed. E-mail: dvtalapin@uchicago.edu. † The University of Chicago. ‡ Argonne National Lab. Chem. Rev. 2010, 110, 389–458 389

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Prospects of Colloidal Nanocrystals for Electronic and Optoelectronic Applications

https://cyberleninka.org/article/n/1018032.pdf

Polymer nanotechnology: Nanocomposites

"United we stand, divided we fall."--Aesop. Aggregation-induced emission (AIE) refers to a photophysical phenomenon shown by a group of luminogenic materials that are non-emissive when they are dissolved in good solvents as molecules but become highly luminescent when they are clustered in poor solvents or solid state as aggregates. In this Review we summarize the recent progresses made in the area of AIE research. We conduct mechanistic analyses of the AIE processes, unify the restriction of intramolecular motions (RIM) as the main cause for the AIE effects, and derive RIM-based molecular engineering strategies for the design of new AIE luminogens (AIEgens). Typical examples of the newly developed AIEgens and their high-tech applications as optoelectronic materials, chemical sensors and biomedical probes are presented and discussed.

Aggregation-Induced Emission: The Whole Is More Brilliant than the Parts

In this Progress Report we provide an update on recent developments in inkjet printing technology and its applications, which include organic thin-film transistors, light-emitting diodes, solar cells, conductive structures, memory devices, sensors, and biological/pharmaceutical tasks. Various classes of materials and device types are in turn examined and an opinion is offered about the nature of the progress that has been achieved.

Inkjet Printing—Process and Its Applications

Inkjet printing is an attractive patterning technology, which has become increasingly accepted for a variety of industrial and scientific applications. This review primarily presents an overview of the investigations that have been conducted since 2003 into inkjet-printing polymers or metal-containing inks and mentions related activities. The first section discusses the droplet-formation process in piezoelectric drop-on-demand printheads and the physical properties that affect droplet formation and the resolution of inkjet-printed features. The second section deals with the issues that arise from printing polymers, such as printability and the output characteristics of devices made by this route. Finally, the challenges and achievements attached to inkjet printing metal-containing inks are discussed before concluding with a few remarks about the future of the field.

Inkjet printing as a deposition and patterning tool for polymers and inorganic particles

Recent results on the ink-jet printing of polymer films are presented. Films that were printed using an ink-jet process based on one single solvent always suffered from ring formation, i.e. the coffee-drop effect. This drawback could be overcome by the use of solvent mixtures. The effects of solvent mass ratio, print head velocity, dot spacing and printing method were investigated and optimized to reproducibly obtain homogeneous polymer films (6 × 6 mm size). The results obtained represent an important step towards the application of ink-jet printing for the controlled deposition of polymer dots and libraries.

Ink-jet printing of polymers – from single dots to thin film libraries

Inkjet printing is used to produce well-defined patterns of dots (with diameters of ca. 120 μm) that are composed of luminescent CdTe nanocrystals (NCs) embedded within a poly(vinylalcohol) (PVA) matrix. Addition of ethylene glycol (1–2 vol %) to the aqueous solution of CdTe NCs suppresses the well-known ring-formation effect in inkjet printing leading to exceptionally uniform dots. Atomic force microscopy characterization reveals that in the CdTe NC films the particle–particle interaction could be prevented using inert PVA as a matrix. Combinatorial libraries of CdTe NC–PVA composites with variable NC sizes and polymer/NC ratios are prepared using inkjet printing. These libraries are subsequently characterized using a UV/fluorescence plate reader to determine their luminescent properties. Energy transfer from green-light-emitting to red-light-emitting CdTe NCs in the composite containing green- (2.6 nm diameter) and red-emitting (3.5 nm diameter) NCs are demonstrated.

Inkjet Printing of Luminescent CdTe Nanocrystal–Polymer Composites

A detailed survey on the processing of poly[2-methoxy-5-(2′-ethylhexyloxyl)–1,4-phenylenevinylene] (MEH–PPV) solutions via ink-jet printing and the subsequent characterization of the resulting films is reported. The printability of MEH–PPV dissolved in different solvents, and with varied concentrations, is studied. Limitations of the printability of highly concentrated polymer solutions are overcome by using ultrasonication. The pattern formation of the resulting lines is explained in relation to the contact angle formed by the MEH–PPV solution on the substrate and interchain interactions. A uniform thickness distribution of MEH–PPV films is obtained when toluene is used as the solvent. Further improvement on the surface quality of the lines is achieved by optimizing the printing parameters. The line stability as a function of the print-head velocity is also studied. Additionally, current–voltage (I–V) characteristics and the morphology of the MEH–PPV films, as determined by atomic force microscopy, are discussed.

Controlled Pattern Formation of Poly[2-methoxy-5-(2′-ethylhexyloxyl)–1,4-phenylenevinylene] (MEH–PPV) by Ink-Jet Printing†

Defined films of luminescent ruthenium(II) polypyridyl-poly(methyl methacrylate) (PMMA) and iridium(m) polypyrldyl-polystyrene (PS) copolymers could be prepared by ink-jet printing. The copolymers were deposited on photoresist-patterned glass substrates. Films as thin as 120 nm could be printed with a roughness of 1 to 2%. In addition, the film thickness cold be varied in a controlled way through the number of droplets deposited per unit area. The topography of the ink-jet printed films was analyzed utilizing an optical profilometer. The absorbance and emission spectra were measured using fast parallel UV-vis and fluorescence plate reader.

Emine Tekin

Papers

Inkjet printing as a deposition and patterning tool for polymers and inorganic particles

Ink-jet printing of polymers – from single dots to thin film libraries

Inkjet Printing of Luminescent CdTe Nanocrystal–Polymer Composites

Controlled Pattern Formation of Poly[2-methoxy-5-(2′-ethylhexyloxyl)–1,4-phenylenevinylene] (MEH–PPV) by Ink-Jet Printing†

Ink‐Jet Printing of Luminescent Ruthenium‐ and Iridium‐Containing Polymers for Applications in Light‐Emitting Devices