Application Of 3D Printing Research Articles

Development of Inclined Applicators for Flattened Beam Intraoperative Radiotherapy

A 3D-printed applicator for intraoperative radiation therapy (IORT) using the INTRABEAM system has been introduced, designed to protect normal tissue, expand indications, and assess its effectiveness in various intraoperative settings. The study involved designing and creating inclined applicators at 0° and 45° angles, which were capable of producing flattened and unflattened beams and shielding non-target areas from radiation. The applicator was evaluated based on dose uniformity, percentage depth dose, leakage, and dose rate. The findings showed that the applicator provided a uniform beam at various depths (1.23 to 1.30 for the flattened beam and 1.25 to 1.32 for the unflattened beam) and effectively shielded against leakage, with no leakage dose measured at 1 mm from the surface. Additionally, the dose rates after 3 min of irradiation for flattened and unflattened beams were 51.0 and 52.9 cGy for 0° and 48.5 and 54.8 cGy for 45° applicators, respectively. This suggests that the applicator can efficiently deliver IORT while minimizing exposure to normal tissues, particularly in treating chest and abdominal lesions near or on critical organs. The applicator has undergone dose calibration and has moved forward to clinical application.

Development of bean-based emulgels for 3D printing applications: Feasibility for dysphagia diets

Emulgels could be used as edible inks for individuals with special needs. The purpose of this work was to formulate a 3D printable low-oil emulgel by evaluating the effect of incorporating gelatin in a bean-based nanoemulsion stabilized by high-pressure homogenization (HPH) suitable for a dysphagia diet. The effect of physicochemical properties and printing parameters of the emulsion network were evaluated for printability, dimensional stability, and textural properties. HPH produced stable nanoemulsions using pressures >200 MPa and 5% bean protein. Adding gelatin decreased NH and COO vibrations, increased hydrogen bonding, and created self-supporting emulgels when the gelatin concentration was >1.5%. Printing performance, dimensional stability, and textural properties depended on the gelatin concentration and printing parameters, whose improvement enabled precise, time-stable, and swallow-safe shapes with 2.5% gelatin. In conclusion, stable emulgels can be used in 3D printing, facilitating the design of colloidal food systems with customized textures and nutritional properties for individuals with dysphagia.

Development and photothermal effects of AgNPs and AgNWs nanocomposites for the design of printed scaffolds for organic tissue supports

The aim of this work was to design and build novel scaffolds of different composition for application of 3D printing in organic tissues and to determine the thermal properties of these nanocomposites; therefore, novel silver/acrylic composites based on silver nanoparticles (AgNPs) of 15.7 nm average in diameter synthesized by a green method, and silver nanowires (AgNWs) of 50 nm in diameter and 1.5 µm in length synthesized by the polyol method were successfully prepared. Thermal lens spectroscopy (TLS) in a mismatched configuration was used to determine the liquid sample’s thermal diffusivity (D), and photoacoustic spectroscopy (PA) in an open cell (OPC) configuration was used to determine the nanocomposite’s characteristic curing time (τ). Values of D for the AgNPs range from 14.8 x 10-8 to 47.4 x 10-8 m2/s (4.5 to 18.5 x 10-5 wt%) with curing times (τ) of 26.7 to 57.7 s. On the other hand, the values of D for the AgNWs composites were between 6.6 x 10-8 and 36.6 x 10-8 m2/s (4.1 to 16.5 x 10-5 wt%) with curing times (τ) of 482.9 s to 1650.9 s (4.1 to 12.8 x 10-5 wt%). Scaffolds were 3D printed with a lithographic printer prototype whose experimental variables were optimized using an experimental design (DOE). Characterization techniques as transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FTIR), and UV–vis spectroscopy were used to determine AgNPs, AgNWs and resin’s morphology, physical and chemical aspects. Shore hardness D tester was used to analyze the scaffolds mechanical behavior with a linear increase for the AgNPs composites and non-linear trend for the AgNWs composites. From the results, an improvement and optimization of the thermal diffusivity, mechanical properties and curing time of the new nanocomposites was obtained with the increase in concentration.

Surimi freshness monitoring of 4D printing material with anthocyanin

This study proposed a new idea about 3D printing. It provided a feasible attempt for the application of 3D printing in the preservation and processing of aquatic products. Surimi is a kind of food rich in protein and easy to deteriorate. We tried to add xylo-oligosaccharide and CaCl2 to surimi, which improved twice gel strength and quadruple hardness of surimi. It is difficult to detect deterioration during refrigeration. We have designed a gel that can be wrapped on surimi through a dual nozzle 3D printer. The gel was in direct contact with surimi. The gel made of 5% carrageenan, 5% xanthan gum and 1% hydroxymethyl cellulose would change color with the change of pH of surimi after wrapping the surimi. Because anthocyanins have different color characteristics at different pH, the pH of surimi can be known through color change.

WITHDRAWAL: Medical Imaging Technology, 3D Printing and Medical Applications

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High internal phase emulsion stabilized by whey protein isolate-gum Arabic Maillard conjugate: Characterization and application in 3D printing

High internal phase emulsions (HIPEs) stabilized by protein-polysaccharide are attracting considerable attention in the food industry and have been used in the emerging 3D printing. However, research on protein-polysaccharide Maillard conjugates with health-promoting effects used in HIPEs and 3D printing is limited. Developing HIPEs with enhanced stability, printability, and desirable functional properties remains a challenge. This study was aimed to investigate the potential of whey protein isolate-gum Arabic Maillard conjugates (WPI-GA-C) as emulsifiers for stabilizing HIPEs and to prepare HIPEs with improved properties for personalized functional foods and 3D printing. The effects of WPI-GA-C concentration and oil mass fraction on the properties of HIPEs were systematically characterized. The results showed that the WPI-GA-C concentration and oil mass fraction had significant effects on the particle size, processability, and textural, rheological and 3D printing properties of HIPEs. The HIPEs stabilized with 3% WPI-GA-C and 80% oil mass fraction exhibited better self-supporting properties, higher viscosity, higher storage modulus, and lower frequency dependence compared with HIPEs prepared with lower WPI-GA-C concentrations (1% and 2%) and lower oil mass fractions (74% and 77%). The prepared HIPEs could be used as food-grade 3D printing inks to print models with good dimensional printing accuracy. In conclusion, WPI-GA-C could be used to prepare stable HIPEs as potential inks for 3D printing. These results provided new insights into personalized functional food applications with protein-polysaccharide Maillard conjugate stabilized emulsions.

Slag-modified metakaolin-based geopolymer for 3D concrete printing application: Evaluating fresh and hardened properties

Slag-modified metakaolin-based geopolymer for 3D concrete printing application: Evaluating fresh and hardened properties

Development of Ultra-High-Performance Silica Fume-Based Mortar Incorporating Graphene Nanoplatelets for 3-Dimensional Concrete Printing Application

Although the use of 3D printing in civil engineering has grown in popularity, one of the primary challenges associated with it is the absence of steel bars inside the printed mortar. As a result, developing 3D printing mortar with ultra-high compressive, flexural, and tensile strengths is critical. In the present study, an ultra-high-performance mortar incorporating silica fume (SF) and graphene nanoplatelets (GNPs) was developed for 3D printing application. The concrete mixture added SF to the concrete mixture in the range between 0% and 20%, while GNPs were added as a partial replacement by cement weight from 0.5% to 2%. The flowability and the machinal properties of the proposed mortar, including compressive (CS), tensile (TS), and flexural strength (FS), were investigated and assessed. Microstructure analysis involving FESEM and EDX was also investigated and evaluated, while response surface methodology (RSM) was considered to predict and optimize the optimum value of GNPs and SF. Workability results show that the flowability is reduced when the amount of graphene increases. Based on the predicted and experimental results, ultra-high-strength mortar can be developed by including 1.5% of GNPs and 20% of SF, in which the CS jumped from 70.7 MPa to 133.3 MPa at the age of 28 days. The FS and TS were 20.66 MPa and 14.67 MPa compared to the control mix (9.75 MPa and 6.36 MPa), respectively. This favorable outcome was credited to the pozzolanic activity of SF and the effectiveness of GNPs in compacting the pores and bridging the cracks at the nanoscale level, which were verified by FE-SEM and EDX. In addition, the developed quadratic equations proved their accuracy in predicting and optimizing the mechanical properties with low error (less than 0.09) and high correlation (R2 > 0.97). It can be concluded that the current work is an important step forward in developing a 3D printing mortar. The lack of reinforcement in the printed mortar structure has been a considerable difficulty, and the SF and GNPs have increased the compressive, flexural, and tensile strengths of the mortar. Thus, these improvements will encourage the industry to utilize sustainable materials to produce more affordable housing.

Research on Cartilage 3D Printing Technology Based on SA-GA-HA.

Cartilage damage is difficult to heal and poses a serious problem to human health as it can lead to osteoarthritis. In this work, we explore the application of biological 3D printing to manufacture new cartilage scaffolds to promote cartilage regeneration. The hydrogel made by mixing sodium alginate (SA) and gelatin (GA) has high biocompatibility, but its mechanical properties are poor. The addition of hydroxyapatite (HA) can enhance its mechanical properties. In this paper, the preparation scheme of the SA-GA-HA composite hydrogel cartilage scaffold was explored, the scaffolds prepared with different concentrations were compared, and better formulations were obtained for printing and testing. Mathematical modeling of the printing process of the bracket, simulation analysis of the printing process based on the mathematical model, and adjustment of actual printing parameters based on the results of the simulation were performed. The cartilage scaffold, which was printed using Bioplotter 3D printer, exhibited useful mechanical properties suitable for practical needs. In addition, ATDC-5 cells were seeded on the cartilage scaffolds and the cell survival rate was found to be higher after one week. The findings demonstrated that the fabricated chondrocyte scaffolds had better mechanical properties and biocompatibility, providing a new scaffold strategy for cartilage tissue regeneration.

Investigating the thermal and mechanical properties of novel LDPE/TiO2 and LDPE/TiO2/CNT composites for 3D printing applications.

The development of new materials is essential for advancing technology and improving the quality of life. With new materials, we can create products that are stronger, more durable, and more efficient. The ongoing research and development of new materials for 3D printing applications continue to drive innovation in various fields, leading to improved products and processes with great benefits. The main goal of this work was to produce a functional filament with a 1.75-mm diameter that may be used for 3D printing. Composite materials were prepared using a low-density polyethylene (LDPE) resin as polymer matrix, and titanium dioxide (TiO2) and carbon nanotubes (CNT) as fillers in various ratios. Up to 15 wt% of TiO2 and 0.25 wt% of CNT were added. Some of the greatest difficulties with high filler content composites are achieving good homogeneity, and in the case of the 3D printing, greatest difficulties are producing the filament with a specific and stable filament diameter. During the 3D printing itself, the fillers can also often cause the nozzle clogging. This paper reports findings of thermal and mechanical properties of the LDPE/TiO2/CNT composites which are significant for the 3D printing process and the applicability of the composite materials. All of the planed composite materials are successfully prepared and 3D printed into the tensile test specimens. The melting point shift caused by the addition of fillers did not show consistent pattern at differential scanning calorimetry, as all of the samples had melting temperatures around 113.5 ± 1.4 °C. The addition of filler, according to the TGA, increased the threshold temperature for the material decomposition, in case of TiO2 5.4 °C increase, while TiO2 and CNT combination increased the threshold temperature for 6.8 °C. The results of the tensile test show a general increase trend with addition of TiO2 filler but do not show to a trend for the tensile strength as a result of the addition of CNT filler. The sample with highest TiO2 filler ratio of 15% (LDPE 15T0C) showed the greatest tensile strength of 14.5 MPa, compared to the 13.0 MPa of pure LDPE. The sample with 5% of TiO2 filler and 0.1% of CNT filler (LDPE 5T0.1C) showed the greatest elongation of 73.9%, compared to the 68.9% of pure LDPE.

Improvement of 3D printing performance of pea protein isolate Pickering emulsion gels by regulating electrostatic interaction between protein and polysaccharide

3D food printing had attracted wide attention for its multiple advantages such as being able to customize food according to individual needs. In this study, plant-based edible inks suitable for 3D food printing applications were formulated using Pickering emulsion gels containing pea protein isolate (PPI) and flaxseed gum (FG). The effect of different electrostatic interaction between PPI and FG on the 3D printing performance, rheology properties and microstructure of emulsion gel inks were investigated in acidic (pH 3) and neutral (pH 7) environments, respectively. At pH 3, the inks showed good printing performance with the addition of FG at 0.5%, 0.7% and 0.9%, respectively. At pH 7, the inks at 0.5% had the best 3D printing performance. They demonstrated printing performance with precise shape, smooth surface and clear texture. The inks produced were soft matter solids with a storage modulus (G′) greater than the loss modulus (G″). According to Lissajous plots analysis, the addition of FG significantly improved the viscoelasticity, which was beneficial to improve the 3D printing performance of inks. These inks also exhibited good thermal stability. In addition, Cryo-SEM analysis showed that the inks had a striated structure at pH 3 but a honeycomb structure at pH 7 due to the difference in electrostatic interaction. And the honeycomb structure is more stable compared to the striated structure. This study showed that edible inks can be formulated from plant-derived ingredients, which may increase their application in the development of plant-based foods with improved properties using additive manufacturing processes.

Nanoclay-reinforced alginate/salecan composite inks for 3D printing applications

The main objective of the present work was to produce three-dimensional (3D)- printable nanocomposite hydrogels based on two kinds of marine-sourced polysaccharides doped with nanoclay with potential biomedical application. First part of the research study investigated the preparation of the polysaccharide bicomponent hydrogel formulations followed by the selection of the optimal ratio of polysaccharides concentrations which ensured proper morphostructural stability of the 3D-printed constructs. Second step aimed to generate 3D scaffolds with high printing fidelity by modulating the nanoclay amount doped within the previously selected biopolymer ink. In compliance with the additive manufacturing experiments, the alginate–salecan hydrogels enriched with the highest nanofiller concentrations demonstrated the highest suitability for 3D printing process. The morphological and structural studies confirmed the ability of the nanocomposite formulations to efficiently produce porous 3D-printed constructs with improved fidelity. The morphostructural findings underlined the implication of choosing the appropriate ratio between components, as they have a considerable impact on the functionality of printing formulations and subsequent 3D-printed structures. Hence, from the obtained results, these novel hydrogel nanocomposites inks are considered valuable biomaterials with suitable features for applications in the additive manufacturing of 3D structures with precise shape for customized regenerative therapy.  

A multifunctional hydrogel based on nature polysaccharide fabricated by Schiff base reaction

A multifunctional hydrogel derived from carboxymethyl chitosan (CMCS) and oxidized hyaluronic acid (OHA), was fabricated by Schiff base reaction between the amino groups of CMCS and aldehyde groups in OHA. The aldehyde groups of OHA were prepared through the oxidation of hydroxy groups of hyaluronic acid (HA) by NaIO4, and the oxidation degree of OHA can be adjusted by varying amount of NaIO4. Furthermore, the gelation time, mechanical strength, swelling and deswelling properties of gels are different with varying the concentration of precursor solution. This hydrogel shows an excellent swelling capacity of 6000 % for the abounded hydroxyl groups in chains. For the dynamic action of Schiff base action, it also showed a good self-healing capacity to be healed in three minutes around 25 °C. In addition, OHA-CMCS gel had good water or heating induced shape memory property. Moreover, hydrogels with complex structures were fabricated by 3D printing. In a word, the versatility of OHA-CMCS gel makes it could have a widely application for biomedical and 4D printing applications.

The attractiveness of 4D printing in the medical field: Revealing scientific and technological advances in design factors and applications

Currently, there is an increasing demand in the medical field for low-cost, high-quality products as well as personalized solutions, and different manufacturing methods are being investigated to provide innovative solutions. Four-dimensional (4D) printing is a promising technology that could overcome the challenges associated with the applications of three-dimensional printing in regenerative medicine and biomedical devices. A revolution is expected in this regard, and it is essential to keep abreast of the latest developments. Under this context, the purpose of this paper is to reveal scientific and technological advances of 4D printing in the medical field using a competitive technology intelligence (CTI) methodology. To this end, publications were analyzed from the Scopus database between January 1, 2017, and May 9, 2023. The main trends were identified for both design factors and applications. In the first case, the following were considered: 4D printing methods, external stimuli, materials, mathematical models, and interaction mechanisms. In contrast, in the second case, the applications of 4D printing involved were considered: drug delivery systems, stents, and scaffolds. The obtained design factors results included improvements in mechanical properties of hydrogels by adding magnetic nanoparticles, biopolyurethane, and other materials, the development of cell-friendly bioprinting methods to print cellular structures, and the use of theoretical-experimental approaches to predict shape deformation of structures. While for applications, results included advances in the development of expandable drug delivery systems, fabrication of stents for the treatment of vascular and tracheal stenosis, and the design of scaffolds to treat cartilage defects and bone regeneration. This study provides insights to researchers, academics, and companies involved in research and development as well as innovation that are looking for new solutions to improve health by incorporating breakthrough technologies such as 4D printing.

Organ sparing treatment for penile cancer using a 3D-printed high-dose-rate brachytherapy applicator

PURPOSEWe present a case study of the treatment of localized squamous cell carcinoma on the glans penis with a custom-fabricated high-dose-rate (HDR) brachytherapy applicator. METHODS AND MATERIALSA cylindrically shaped applicator was fabricated with eight embedded channels suitable for standard plastic brachytherapy catheters. An additional custom silicone bolus/sleeve was designed to be used with the 3D-printed applicator to provide an additional offset from the source to skin to reduce the surface dose and for patient comfort. RESULTSThe patient (recurrent cT1a penile cancer) underwent CT simulation, and the brachytherapy plan was created with a nominal prescription dose of 40 Gy in 10 fractions given bidaily to the surface, and 35 Gy at 5 mm depth. Dose coverage to the clinical target volume was 94% (D90). Most fractions were treated with only 5-10 min of setup time. Follow up visits up to 1 year showed no evidence of disease with no significant changes in urinary and sexual function and limited cosmetic detriment to the patient. CONCLUSIONSPatient-specific organ-sparing HDR plesiotherapy using 3D printing technology can provide reliable and reproducible patient setup and may be effective in achieving disease control for superficial penile cancer, although preserving patient quality of life.

Advances of 3D printing in gastroenterology and where it might be going

Gastrointestinal (GI) system comprises a great number of organs and tissues of various functions, both hollow and solid. However, it is still a less well-developed area for three-dimensional (3D) printing (3DP) applications compared to orthopedics. Clinical applications of 3DP in the GI system are presently restricted to preoperative planning, surgical guidance, and education for students, residents, and patients, either for laparoscopy or endoscopy. Several surgery-related accessories have been designed to facilitate surgical procedures. The results are promising but not adequately proven due to a lack of reasonable study design and proper comparisons. Other important requirements for GI systems in clinical scenarios are structural reconstruction, replacement, defect repair, drug screening, and delivery. Many 3D-printed decellularized, cell-seeded, or even bioprinted scaffolds have been studied; however, most studies were conducted on small animal or in vitro models. Although encouraging results have been obtained, there is still a long way to go before products compatible with humans in size, histology, and functions can be printed. The key points to achieving this goal are the printing material, cell type and source, and printing technology. The ultimate goal is to print tissue and organ substitutes with physiological functions for clinical purposes in both time- and cost-effective ways.

Application of 3D Printing in Medicine: Technologies and Challenges

Application of 3D Printing in Medicine: Technologies and Challenges

Application of 3D Printing in Medicine: Technologies and Challenges

Application of 3D Printing in Medicine: Technologies and Challenges

Revalorisation of tamarind seed waste for improved PLA wear and hydrophilic behaviour in 3D printing applications

Revalorisation of tamarind seed waste for improved PLA wear and hydrophilic behaviour in 3D printing applications

Structural design and engineering of Striatus, an unreinforced 3D-concrete-printed masonry arch bridge

This paper describes the structural design and engineering of “Striatus”, a 3D-concrete-printed unreinforced masonry pedestrian bridge built in Venice in 2021 as part of the Time Space Existence exhibition organised by the European Cultural Centre. The project combines the latest developments in 3D concrete printing with the structural principles of historic unreinforced masonry. Typically, the structural applications of 3D concrete printing are limited to elements such as columns and walls loaded vertically, perpendicularly to the horizontal printing layers, to formwork elements or secondary structural elements. Indeed, fabrication constraints, delamination issues and the low tensile strength of the concrete have been seen as limiting factors to 3D concrete printing for structural applications demanding resistance to bending or predominant loading directions not perpendicular to the printing layers. By using unreinforced-masonry structural principles, this paper shows that structural elements spanning space horizontally, such as a pedestrian bridge, can be built by using the 3D concrete printing components as the main structure, working only in compression, loaded perpendicularly to the printed layers. Furthermore, as a compression-only structure following masonry principles, Striatus enabled the use of unreinforced concrete without any mechanical or chemical connections between the elements and the separation of concrete and steel, only used for the supports and to equilibrate the horizontal thrust of the arch effect through the tension ties. This work shows how the application of unreinforced masonry principles to 3D concrete printing offers new opportunities in terms of structural design and represents a strategy to increase sustainability by reducing material consumption and allowing reusability and recyclability of the structure. Finally, this paper discusses the critical aspects related to the design of Striatus from an engineering and construction point of view.