Abstract:Two simple, mechanical modifications are introduced to a consumer-grade inkjet printer to greatly increase its applicability. First, roller isolation bars are added to unlock multiple prints on the same substrate without smearing. This enables printing on a diverse set of substrates (rigid, elastic, liquid, granular, and sticky). Second, spring loadings are added to increase the print precision up to 50-fold, which facilitates alignment to a pre-patterned substrate or between successive prints. Utilizing the e… Show more
“…We observed that the ability to vary volumes via acceleration‐mode dip‐coating remains significant as the droplet base diameter is decreased, which means that the method likely also works for both smaller and larger footprints than the 50 µm to 6 mm range we have tested. This is important because the ability to create gradient arrays in a parallel manner becomes increasingly more important as droplets are scaled down, due to difficulties creating the droplets via other techniques (such as inkjet printing, [ 29 ] even when acoustophoretic printing is employed [ 30 ] ) and the large number of droplets makes it time‐consuming to produce them drop‐by‐drop.…”
Droplet microarray technology is of great interest in biology and chemistry as it allows for significant reactant savings and massive parallelization of experiments. Upon scaling down the footprint of each droplet in an array, it becomes increasingly challenging to produce the array drop‐by‐drop. Therefore, techniques for parallelized droplet production are developed, e.g., dip‐coating of biphilic substrates. However, it is in general difficult to tailor the characteristics of individual droplets, such as size and content, without updating the substrate. Here, the method of dip‐coating of uniformly patterned biphilic substrates in so‐called “acceleration‐mode” to produce droplet arrays featuring gradients in droplet height for fixed droplet footprint is developed. The results herein present this method applied to produce drops with base diameters varying over orders of magnitude, from as high as 6 mm to as small as 50 µm; importantly, the experimentally measured power‐law‐dependency of volume on capillary‐number matches analytical theory for droplet formation on heterogenous substrates though the precise quantitative values likely differ due to 2D substrate patterning. Gradient characteristics, including average droplet volume, steepness of the gradient, and its monotonicity, can all be tuned by changing the dip‐coating parameters, thus providing a robust method for high‐throughput screening applications and experiments.
“…We observed that the ability to vary volumes via acceleration‐mode dip‐coating remains significant as the droplet base diameter is decreased, which means that the method likely also works for both smaller and larger footprints than the 50 µm to 6 mm range we have tested. This is important because the ability to create gradient arrays in a parallel manner becomes increasingly more important as droplets are scaled down, due to difficulties creating the droplets via other techniques (such as inkjet printing, [ 29 ] even when acoustophoretic printing is employed [ 30 ] ) and the large number of droplets makes it time‐consuming to produce them drop‐by‐drop.…”
Droplet microarray technology is of great interest in biology and chemistry as it allows for significant reactant savings and massive parallelization of experiments. Upon scaling down the footprint of each droplet in an array, it becomes increasingly challenging to produce the array drop‐by‐drop. Therefore, techniques for parallelized droplet production are developed, e.g., dip‐coating of biphilic substrates. However, it is in general difficult to tailor the characteristics of individual droplets, such as size and content, without updating the substrate. Here, the method of dip‐coating of uniformly patterned biphilic substrates in so‐called “acceleration‐mode” to produce droplet arrays featuring gradients in droplet height for fixed droplet footprint is developed. The results herein present this method applied to produce drops with base diameters varying over orders of magnitude, from as high as 6 mm to as small as 50 µm; importantly, the experimentally measured power‐law‐dependency of volume on capillary‐number matches analytical theory for droplet formation on heterogenous substrates though the precise quantitative values likely differ due to 2D substrate patterning. Gradient characteristics, including average droplet volume, steepness of the gradient, and its monotonicity, can all be tuned by changing the dip‐coating parameters, thus providing a robust method for high‐throughput screening applications and experiments.
“…Among all the printing methods, inkjet printing, a digital manufacturing technique renowned for its precision, versatility, and scalability, offers the potential to create customized drug delivery devices with unparalleled precision in drug loading and spatial distribution. It could not only customize and tailor drug dosages according to the specific needs of a patient [ 80 , 81 ] but also allow drug delivery systems with specific release profiles [ 82 , 83 ], such as delayed or sustained release, as shown in Fig. 6 A.…”
Section: Emerging Biomedical Advancesmentioning
confidence: 99%
“…This is of importance in scenarios where a gradient of drug concentration (as demonstrated in Fig. 6 B) or co-delivery of multiple therapeutics in defined ratios can enhance therapeutic outcomes [ 81 ]. Fig.…”
Section: Emerging Biomedical Advancesmentioning
confidence: 99%
“…Reprinted from [ 83 ] under a Creative Commons license; B Consumer-Grade Inkjet Printer for personalized medicine. Reprinted from [ 81 ] under a Creative Commons license—(i) Schematic of the inkjet system during the reactant loading of the microfluidic system; (ii) Optical microscopy images of the micro-containers after the 1st and 10th print, which demonstrates the possibility to do tailored loading with minimal waste; (iii-top) Temporal drug release spectra from microcontainers loaded with first 10 doses/layers of either propranolol or furosemide and then 5 doses/layers of the other drug. (iii-bottom) Using the unmixed signals, the temporal spectra are decomposed to visualize the release kinetics for the individual drugs in the two loading examples …”
Hydrogels with particulates, including proteins, drugs, nanoparticles, and cells, enable the development of new and innovative biomaterials. Precise control of the spatial distribution of these particulates is crucial to produce advanced biomaterials. Thus, there is a high demand for manufacturing methods for particle-laden hydrogels. In this context, 3D printing of hydrogels is emerging as a promising method to create numerous innovative biomaterials. Among the 3D printing methods, inkjet printing, so-called drop-on-demand (DOD) printing, stands out for its ability to construct biomaterials with superior spatial resolutions. However, its printing processes are still designed by trial and error due to a limited understanding of the ink behavior during the printing processes. This review discusses the current understanding of transport processes and hydrogel behaviors during inkjet printing for particulate-laden hydrogels. Specifically, we review the transport processes of water and particulates within hydrogel during ink formulation, jetting, and curing. Additionally, we examine current inkjet printing applications in fabricating engineered tissues, drug delivery devices, and advanced bioelectronics components. Finally, the challenges and opportunities for next-generation inkjet printing are also discussed.
Graphical Abstract
“…Biomedical additive manufacturing is gaining popularity for low-cost prototyping and manufacturing due to its advantages in noncontact printing, speed, and accuracy. − Recently, droplet-based two-dimensional (2D) and three-dimensional (3D) printing techniques like inkjet printing have become hot research focus for appropriate pharmaceutical applications, − allowing the creation of personalized medicine and targeted drug delivery system through automated control over drug doses and releases, making the vision of patient-specific treatment on the horizon tangible reality. ,,− However, further exploration and optimization are needed to fully utilize the capabilities of droplet-based 2D and 3D printing techniques in healthcare applications. One of the main challenges associated with droplet-based printing techniques in the preparation of personalized medicines is the development of pharmaceutical inks (similar to bioinks in bioprinting) with suitable mechanical characteristics and adjustable drug release time. ,, Pharmaceutical inks are meticulously formulated inks that contain drugs and excipient substances.…”
Glucose modifies the mechanical stability of coffee films and facilitates their dissolution dynamics at the microscale, rendering glucose-coffee a valuable natural biomaterial system for studying pharmaceutical applications. We show the glucosedependent inhibition of crack propagation during the evaporation of glucose-coffee droplets. The addition of glucose increases the hardness, stiffness, and shear modulus of films, as measured by surface nanomechanical testing. The glucose-coffee film dissolves faster and more evenly than the pure coffee film through interfaces. The water penetrates through well-dissolved glucose channels. The modified mechanical properties and adjustable dissolution time, coupled with edibility, position the glucose-modified coffee as an excellent candidate for developing pharmaceutical inks for personalized medicine droplet-based printing.
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