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The digital light processing (DLP) printer has proven to be effective in biomedical and pharmaceutical applications, as its printing method does not induce shear and a strong temperature on the resin. In addition, the DLP printer has good resolution and print quality, which makes it possible to print complex structures with a customized shape, being used for various purposes ranging from jewelry application to biomedical and pharmaceutical areas. The big disadvantage of DLP is the lack of a biocompatible and non-toxic resin on the market. To overcome this limitation, an ideal resin for biomedical and pharmaceutical use is needed. The resin must have appropriate properties, so that the desired format is printed when with a determined wavelength is applied. Thus, the aim of this work is to bring the basic characteristics of the resins used by this printing method and the minimum requirements to start printing by DLP for pharmaceutical and biomedical applications. The DLP method has proven to be effective in obtaining pharmaceutical devices such as drug delivery systems. Furthermore, this technology allows the printing of devices of ideal size, shape and dosage, providing the patient with personalized treatment.

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The patterning of hydrophilic paper with hydrophobic materials has emerged as an interesting method for the fabrication of paper-based devices (PADs). Herein, we demonstrate a digitally automated, easy, low-cost, eco-friendly, and readily available method to create highly hydrophobic barriers on paper that can be promptly employed with PADs by simply using a bioink made with rosin, a commercially available natural resin obtained from conifer trees. The bioink can be easily delivered with the use of a ballpoint pen to produce water- and organic solvent-resistant barriers, showing superior properties when compared to other methods such as wax-printing or permanent markers. The approach enables the pen to be attached to a commercially available cutting printer to perform the semiautomated fabrication of hydrophobic barriers for PADs. With the aid of digitally controlled optimization, together with features of machine learning and design of experiments, we show a thorough investigation on the barrier strength that can be further adjusted to the desired application's needs. Then, we explored the barrier sturdiness across various uses, such as wide range aqueous pH sensing and the harsh acidic/organic conditions needed for the colorimetric detection of cholecalciferol.

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The buccal mucosa appears as a promissory route for biologic drug administration, and pharmaceutical films are flexible dosage forms that can be used in the buccal mucosa as drug delivery systems for either a local or systemic effect. Recently, thin films have been used as printing substrates to manufacture these dosage forms by inkjet printing. As such, it is necessary to investigate the effects of printing biologics on films as substrates in terms of their physical and mucoadhesive properties. Here, we explored solvent casting as a conventional method with two biocompatible polymers, hydroxypropyl methylcellulose, and chitosan, and we used electrospinning process as an electrospun film fabrication of polycaprolactone fibers due to its potential to elicit mucoadhesion. Lysozyme was used as biologic drug model and was formulated as a solution for printing by thermal inkjet printing. Films were characterized before and after printing by mechanical and mucoadhesive properties, surface, and ultrastructure morphology through scanning electron microscopy and solid state properties by thermal analysis. Although minor differences were detected in micrographs and thermograms in all polymeric films tested, neither mechanical nor mucoadhesive properties were affected by these differences. Thus, biologic drug printing on films was successful without affecting their mechanical or mucoadhesive properties. These results open way to explore biologics loading on buccal films by inkjet printing, and future efforts will include further in vitro and in vivo evaluations.

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This chapter describes the development of microfluidic toner-based analytical devices (µTADs) to perform clinical diagnostics using a scanner or cell-phone camera. µTADs have been produced in a platform composed of polyester and toner by the direct-printing technology (DPT) in a matter of minutes. This technology offers simplicity and versatility, and it does not require any sophisticated instrumentation. Toner-based devices integrate the current generation of disposable analytical devices along paper-based chips. The cost of one µTAD has been estimated to be lower than $0.10. In addition, these platforms are lightweight and portable thus enabling their use for point-of-care applications. In the last 5 years, great efforts have been dedicated to spread out the use of µTADs in bioassays. The current chapter reports the fabrication of printed microplates and integrated microfluidic toner-based devices for dengue diagnostics and rapid colorimetric assays with clinically relevant analytes including cholesterol, triglycerides, total proteins, and glucose. The use of µTADs associated with cell-phone camera may contribute to the health care, in special, to people housed in developing regions or with limited access to clinics and hospitals.

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This work describes the quick and simple fabrication of toner-based 96-microzone plates by a direct-printing technology. The printer deposits a toner layer (ca. 5 µm thick) on the polyester surface which acts as a hydrophobic barrier to confine small volumes of sample on test zones (wells). A 96-microzone toner plate was explored to demonstrate its capability of performing enzyme-linked immunosorbent assay (ELISA). The detection of anti-immunoglobulin G (anti-IgG) and immunoglobulin M (IgM) antibodies has been successfully achieved in cell culture and serum samples, respectively. The use of a conventional microplate reader has allowed obtaining a limit of detection of 13 fmol of mouse IgG per zone on printed microplates. The IgM antibody has been detected in a serum sample collected from a patient infected with dengue virus. The detection of a primary infection has been provided by a microplate reader and also by a cell phone camera. Besides the bioanalytical feasibility, toner-based zones have shown good repeatability for inter-zone and intra-plate comparisons. The relative standard deviation (RSD) values for inter-zone (n = 12) and intra-plate (n = 3) comparisons were lower than 6% and 11%, respectively. Furthermore, it was found that the lifetime of each printed microplate depends on the storage temperature. The shelf life for devices stored at 10 °C has been estimated to be ca. four weeks.

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A phase shift proximity printing lithographic mask is designed, manufactured and tested. Its design is based on a Fresnel computer-generated hologram, employing the scalar diffraction theory. The obtained amplitude and phase distributions were mapped into discrete levels. In addition, a coding scheme using sub-cells structure was employed in order to increase the number of discrete levels, thus increasing the degree of freedom in the resulting mask. The mask is fabricated on a fused silica substrate and an amorphous hydrogenated carbon (a:C-H) thin film which act as amplitude modulation agent. The lithographic image is projected onto a resist coated silicon wafer, placed at a distance of 50 microm behind the mask. The results show a improvement of the achieved resolution--linewidth as good as 1.5 microm--what is impossible to obtain with traditional binary masks in proximity printing mode. Such achieved dimensions can be used in the fabrication of MEMS and MOEMS devices. These results are obtained with a UV laser but also with a small arc lamp light source exploring the partial coherence of this source.

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PURPOSE: The purpose of this study was to investigate color change of irises obtained by both printed digital image and painted with gouache, acrylic and oil paints, after polymerization and accelerated aging. MATERIALS AND METHODS: Eight samples simulating ocular prostheses were fabricated. Each sample was constituted by one disc of N1 colored acrylic resin and one disc of colorless acrylic resin with the iris interposed between the discs. The irises in brown and blue color were obtained by painting or by digital image. The specimens' colors were measured with a spectrophotometer using the CIE L*a*b* system, at baseline (B), after polymerization (P), and after 504h (A(1)) and 1008h (A(2)) of accelerated aging. The data were evaluated by 2-way repeated-measures ANOVA and the Tukey's HSD test (alpha=.05). RESULTS: Color change was observed in all samples both after polymerization and after accelerated aging. The different periods of accelerated aging did not influence on color change for the irises painted with blue oil paint. The polymerization promoted a statistical significant effect on the iris color stability for all painting techniques in comparison to all accelerated aging periods. CONCLUSION: After accelerated aging the oil painting technique showed the greatest color stability while the printed digital images technique the worst.

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