Search Results (41)

Current micro/nanosystems mainly rely on a planar fabrication framework, where structures are built layer-by-layer on flat surfaces. This conventional approach leaves vertical sidewalls underutilized, posing geometric limits in packaging density, three-dimensional (3D) interconnects, and multi-surface functionalization. To overcome these constraints, sidewall patterning has emerged as a promising strategy, enabling 3D integrated circuits, templates for directed nanostructure synthesis, and microfluidic drag reduction. Nevertheless, traditional photolithography and non-photolithographic techniques face challenges when applied to vertical or curved 3D surfaces. Unidirectional radiation and restricted focal depths prevent high-fidelity pattern transfer, even when using soft lithography, scanning probes, or nanoimprinting. To address these geometric and mechanical barriers, our group has developed several approaches for patterning the sidewalls of microsystems, which are the primary focus of this review. Building upon our approaches, this review further surveys related sidewall-patterning strategies, including micro-transfer printing, multi-stimuli-responsive mechanics, block copolymer self-assembly, two-photon polymerization, and laser-induced forward transfer. Collectively, these techniques expand the capabilities of sidewall engineering and provide valuable insights into next-generation 3D micro- and nanomanufacturing. Full article

Porous hydrogels are critical for tissue engineering and regenerative medicine, as they mimic the native extracellular matrix to support cell infiltration and mass transport. A common strategy for engineering pore structures involves the incorporation and subsequent removal of sacrificial porogen templates (e.g., crystals or microspheres). Although this approach offers excellent control over pore architecture, it often suffers from complex procedures and biosafety concerns arising from incomplete template removal. In this work, we present a simple, biocompatible, and versatile templating approach. By systematically investigating the coacervation parameters, we produced gelatin microspheres (GSs) with tunable diameters from 7 µm to 300 µm via a green, instrument-free, and scalable process. Using GSs of 20–160 µm as porogens, we obtained alginate hydrogels with adjustable viscoelasticity, stiffness, and pore sizes. We then validated two cell-loading strategies for bulk porous alginate hydrogels using immortalized human T (Jurkat) cells: (i) post-seeding into pre-formed pores supported high-density, long-term, and organized cell aggregates with >90% viability; (ii) in situ encapsulation (prior to pore formation) yielded >80% viability and preserved the cluster-forming growth characteristics of Jurkat cells. Moreover, composites of smaller GSs (7–20 µm) with alginate could be syringe-extruded into stable, sub-millimeter porous filaments, demonstrating the potential for 3D printing. Collectively, this work provides a promising platform for three-dimensional culture of immune cells. Full article

Objectives: The Goel–Harms technique provides rapid stabilization and high fusion rates for atlantoaxial instability but carries a risk of neurovascular injury during lateral mass and pedicle screw insertion. Recently, 3D printing has emerged as a cost-effective and increasingly accessible tool in various surgical fields. This study aimed to compare the clinical and radiological outcomes of C1–C2 fixation using a 3D-printed template versus the free-hand technique. Methods: This retrospective cohort study included patients who underwent C1–C2 fixation with the Goel–Harms technique at two tertiary neurosurgical centers between 2021 and 2023. Operative, radiological, and functional outcomes were reviewed in 21 patients who were operated using either a patient-specific 3D-printed template applied intraoperatively (Group 1; n = 10) or the free-hand technique (Group 2; n = 11). Postoperative screw accuracy was assessed using the Gertzbein–Robbins classification. Results: A total of 84 screws were placed (Group 1: 40; Group 2: 44). In Group 1, 38 of 40 screws (95%) were accurately placed, compared with 41 of 44 screws (93.1%) in Group 2. The mean fluoroscopy and operative times were significantly shorter in Group 1 than in Group 2 (21.90 ± 4.33 s vs. 27.09 ± 13.48 s, p = 0.012; 126.60 ± 28.70 min vs. 171.36 ± 40.44 min, p = 0.010, respectively). Conclusions: The 3D-printed template technique significantly reduced operative and fluoroscopy times compared with the free-hand technique. Three-dimensional printing offers a cost-effective alternative to conventional navigation systems by eliminating their time-consuming preoperative setup in the operating room. Full article

The gut–brain axis (GBA) interaction is important for human health and disease prevention. Organ chips are considered a solution for GBA research. Three-dimensional (3D) cultures and microfluidics engineered in an organ chip could improve the scientific knowledge in the GBA interactions field. In this study, a novel organ chip is developed, which achieves multicellular three-dimensional cultivation by utilizing a decellularized matrix. In addition, this paper reports the rapid prototyping process of the GBA microfluidic chip in polydimethylsiloxane (PDMS) using 3D printing interconnecting poly(ethylene/vinyl acetate) (PEVA) microchannel templates. In comparison to the static culture system of the transwell model, the intestinal epithelial barrier (IEB) and blood–brain barrier (BBB) models on our chip demonstrated superior barrier function and the efflux functionality of transporters under appropriate fluidic conditions. Additionally, it is observed that butyrate protected against BBB dysfunction induced by gut-derived lipopolysaccharide (LPS) via enhancing intestinal barrier function. These results demonstrate that this multicellular, three-dimensional cultivation integrated with a fluidic shear stress simulation chip offers a promising tool for gut–brain interaction study to predict therapy of intestinal and neurological disorders. Full article

The craniofacial skeleton is a complex three-dimensional structure, and major reconstructive cases remain challenging. We describe a synergistic approach combining intra-operative navigation, three-dimensionally (3D) printed skull models, and mixed reality (MR) to improve predictability in surgical outcomes. A patient with previously repaired bilateral cleft lip and palate, significant midfacial retrusion, and a large maxillary alveolar gap underwent segmental Le Fort I osteotomy and advancement. Preoperative virtual planning was performed, and reference templates were uploaded onto MR glasses. Intra-operatively, the MR glasses projected the templates as holograms onto the patient’s skull, guiding osteotomy line marking and validating bony segment movement, which was confirmed with conventional navigation. The 3D-printed skull model facilitated dissection and removal of intervening bony spicules. Preoperative planning proceeded seamlessly across software platforms. Osteotomy lines marked with MR showed good concordance with conventional navigation, and final segment positioning was accurately validated. Postoperative outcomes were satisfactory, with re-established occlusion and closure of the maxillary alveolar gap. The combined use of conventional navigation, 3D-printed models, and MR is feasible and allows safe integration of MR into complex craniofacial reconstruction while further validation of the technology is ongoing. Full article

This in vitro study aimed to quantitatively evaluate the accuracy of reproducing attachments for clear aligner therapy (CAT) using a standardized in-house fabrication protocol and to analyze discrepancies across maxillary tooth types. A custom attachment was designed on a symmetrical master model, and 30 experimental models were fabricated by three-dimensional (3D) printing, template construction, and bonding. Following scanning and superimposition, dimensional, angular, and positional deviations were quantified and statistically analyzed (p < 0.05). Results showed minor mean discrepancies but a consistent pattern of under-reproduction, most evident in the mesial and distal wall angles, as well as in the gingival bevel angle and attachment height. A significant trend was observed in the occlusal bevel, demonstrating marked extrusion in the anterior region that decreased posteriorly. Positional errors were minimal mesiodistally but substantial in the lingual and occlusal directions, with magnitudes varying by tooth type. In conclusion, this study identified consistent, predictable inaccuracies in a simulated in-house attachment reproduction protocol. These findings indicate that similar deviations may occur clinically, potentially affecting the predictability of CAT. Full article

Objectives: This study investigated the use of artificial intelligence (AI) in the design of lingual bracket indirect bonding trays and its association with bracket transfer accuracy using three-dimensional (3D) printing. Methods: Digital impressions of patient’s dental arches were captured using an intraoral scanner, and orthodontic setups were virtually constructed. Brackets were virtually positioned in their ideal locations using the digital setups guided by virtual archwire templates. Indirect bonding trays were automatically generated using the AI-powered Auto Creation function of the Medit Splints application, which analyzes anatomical features to streamline design. Bracket transfer accuracy was evaluated in vivo by comparing planned and actual bracket positions across grouped and individual tray configurations. Linear and angular deviations were measured using conventional 3D inspection software. Results: Most bracket transfer errors were within clinically acceptable thresholds, although torque accuracy remained suboptimal. Grouped trays generally exhibited greater precision than individual trays in several dimensions. Conclusions: These findings support the application of AI-assisted design tools to enhance digital workflows and improve consistency in appliance fabrication. Full article

Achieving precise veneer preparation is essential for optimal esthetic outcome and bonding strength. Advancements in digital technology enable the design and fabrication of stereolithographic templates to guide veneer preparation, significantly improving precision compared to conventional free-hand and silicone guide techniques. Therefore, this study outlines a digital workflow for designing and fabricating a series of Multijet-printed templates following the four essential steps of veneer preparation. The proposed workflow integrates virtual tooth preparation, virtual template design, and fabrication using an additive manufacturing approach and veneer preparation guided by the stackable Multijet-printed template. The result showed that the tooth reduction depth closely matched the required tooth reduction volume in three-dimensional accuracy analysis when using this innovative approach. This marks a transformative development in CAD/CAM dentistry, offering a more predictable and precise approach for veneer preparation, ultimately leading to improved clinical outcomes. Full article

Background/Objectives: Vascularized bone grafts have been successfully established for complex bone defects. The integration of three-dimensional (3D) simulation and printing technology may aid in more precise surgical planning and intraoperative bone shaping. The purpose of the present study was to describe the implementation and surgical application of this innovative technology for bone reconstruction. Methods: This prospective pilot study was conducted between June 2019 and June 2024. For this evaluation, patients who received vascularized bone reconstruction assisted with 3D technology were included. For reconstruction, the free medial femoral condyle (MFC) flap was used as the vascularized bone graft. Patient-specific 3D-printed templates, based on individual 3D simulations according to defect characteristics, were used for surgical planning, including flap elevation, shaping and inset. Results: A total of six patients (five male) with an average age of 39 years (range 19–62 years) and a mean follow-up time of 15 months (range 5–24 months) were analysed. The indications were as follows: avascular necrosis of the carpal bones, a metacarpal defect after tumor resection and pseudoarthrosis after a fractured ulna. Three patients received an osteochondral and three patients received a cortico-cancellous MFC flap. Conclusions: Our evaluation of clinical application revealed enhanced preoperative planning as well as intraoperative performance. Although the implementation for this technology is challenging, the new insights gained in planning and surgical guidance have led us to incorporate this technology into our standard routine. Full article

The use of naturally sourced organic materials with chirality, such as the M13 bacteriophage, holds intriguing implications, especially in the field of nanotechnology. The chirality properties of bacteriophages have been demonstrated through numerous studies, particularly in the analysis of liquid crystal phase transitions, developing specific applications. However, exploring the utilization of the M13 bacteriophage as a template for creating chiral nanostructures for optics and sensor applications comes with significant challenges. In this study, the chirality of the M13 bacteriophage was leveraged as a valuable tool for generating helical hybrid structures by combining it with nanoparticles through an evaporation-induced three-dimensional (3D) printing process. Utilizing on the self-assembly property of the M13 bacteriophage, metal nanoparticles were organized into a helical chain under the influence of the M13 bacteriophage at the meniscus interface. External parameters, including nanoparticle shape, the ratio between the bacteriophage and nanoparticles, and pulling speed, were demonstrated as crucial factors affecting the fabrication of helical nanostructures. This study aimed to explore the potential of chiral nanostructure fabrication by utilizing the chirality of the M13 bacteriophage and manipulating external parameters to control the properties of the resulting hybrid structures. Full article

Fused Deposition Modelling (FDM) is one of the layer-based technologies that fall under the umbrella term “Additive Manufacturing”, where the desired part is created through the successive layer-by-layer addition process with high accuracy using computer-aided design data. Additive manufacturing technology, or as it is commonly known, 3D (three-dimensional) printing, is a rapidly growing sector of manufacturing that is incorporated in automotive, aerospace, biomedical, and many other fields. This work explores the impact of the Additive Manufacturing process on the mechanical proprieties of the fabricated part. To conduct this study, the 3D printed tensile specimens are designed according to the ASTM D638 standards and printed from a digital template file using the FDM 3D printer Raise3D N2. The material chosen for this 3D printing parameter optimization is Polylactic acid (PLA). The FDM process parameters that were studied in this work are the infill pattern, the infill density, and the infill cell orientation. These factors’ effects on the tensile behavior of printed parts were analyzed by the design of experiments method, using the statistical software MINITAB2020. Full article

Introduction: The present study evaluates the influence of virtual surgical planning with a preoperative 3D resin model on aesthetic and functional outcomes in patients treated by segmental mandibulectomy and reconstruction with fibula-free flap for oral cancer. Methods: All consecutive patients who underwent segmental mandibulectomy and mandibular reconstruction with a fibula-free flap using a 3D template at our department from January 2021 to January 2023 were included in the study. “Patients control” were patients treated by reconstruction with a fibula-free flap without using a 3D template. Three-dimensional modeling was performed by converting from preoperative computed tomography to a stereolithography format to obtain the resin 3D models. Qualitative analysis of anatomical and aesthetic results consisted of the evaluation of the patients’ aesthetic and functional satisfaction and the symmetry of the mandibular contour observed at clinical examination. Quantitative analysis was based on the assessment of the accuracy and precision of the reconstruction by comparing preoperative and postoperative computed tomograms as objective indicators. Results: Seven patients (five males and two females, mean age of 65.1 years) were included in the study. All patients showed a symmetric mandibular contour based on the clinical examination. After recovery, six patients (85.7%) considered themselves aesthetically satisfied. The quantitative analysis (assessed in six/seven patients) showed that the mean difference between preoperative and postoperative intercondylar distance, intergonial angle distance, anteroposterior dimension, and gonial angle improved in the 3D template-assisted group. Conclusion: The 3D-printed template for mandibular reconstruction with microvascular fibula-free flap can improve aesthetic outcomes in comparison with standard approaches. Full article

The utilization of lattice-type cellular architectures has seen a significant increase, owing to their predictable shape and the ability to fabricate templated porous materials through low-cost 3D-printing methods. Frames based on atomic lattice structures such as face-centered cubic (FCC), body-centered cubic (BCC), or simple cubic (SC) have been utilized. In FDM, the mechanical performance has been impeded by stress concentration at the nodes and melt-solidification interfaces arising from layer-by-layer deposition. Adding plates to the frames has resulted in improvements with a concurrent increase in weight and hot-pocket-induced dimensional impact in the closed cells formed. In this paper, we explore compressive performance from the partial addition of plates to the frames of a SC-BCC lattice. Compression testing of both single unit cells and 4 × 4 × 4 lattices in all three axial directions is conducted to examine stress transfer to the nearest neighbor and assess scale-up stress transfer. Our findings reveal that hybrid lattice structure unit cells exhibit significantly improved modulus in the range of 125% to 393%, specific modulus in the range of 13% to 120%, and energy absorption in the range of 17% to 395% over the open lattice. The scaled-up lattice modulus increased by 8% to 400%, specific modulus by 2% to 107%, and energy absorption by 37% to 553% over the lattice frame. Parameters that emerged as key to improved lightweighting. Full article

The burden of osteoarthritis (OA) is around 300 million people affected worldwide, with the hip representing a commonly affected joint. Total hip arthroplasty (THA) has been used with notable success as a definitive treatment to improve pain and function in hip OA patients. The recent advent of new technologies, such as 3D printing, has pushed the application of these new concepts toward applications for the well-known THA. Currently, the evidence on the use of 3D printing to aid complex primary THA cases is still scarce. Methods: An extensive literature review was conducted to retrieve all articles centered on the use of 3D printing in the setting of primary THA. Results: A total of seven studies were included in the present systematic review. Four studies investigated the use of 3D-printed surgical guides to be used during surgery. The remaining three studies investigated the benefit of the use of 3D-printed templates of the pelvis to simulate the surgery. Conclusions: The use of 3D printing could be a promising aid to solve difficult primary total hip arthroplasty cases. However, the general enthusiasm in the field is not supported by high-quality studies, hence preventing us from currently recommending its application in everyday practice. Full article

The aim of the present study was to determine the orbital reconstructive effect of customized orbital implants using three-dimensional (3D) printed templates compared with conventional manual-bending implants using computed tomography (CT)-based orbital volume measurements. This retrospective study reviewed the medical records and 3D-CT images of 90 patients who underwent medial, inferior, or inferomedial orbital wall reconstruction. The selected patients were categorized into two groups: (1) the 3D group that underwent surgery using 3D-printed customized orbital implant templates and (2) the manual group that received a conventional manual technique to mold the implant. The volume discrepancy (VD) was obtained by subtracting the volume of the contralateral unaffected eye from that of the injured eye. Of the 90 patients, 33 and 57 were divided into the 3D and manual groups, respectively. The volumes on the contralateral unaffected side and on the pre- and postoperative injured sides were 22.5 ± 2.9, 23.7 ± 3.0, and 22.3 ± 2.8 cm³ (mean ± SD), respectively, in the 3D group, and 21.5 ± 2.5, 22.7 ± 2.8, and 21.2 ± 2.7 cm³ in the manual group. The postoperative VD did not differ between the 3D (–0.2 ± 0.3 cm³) and manual (–0.3 ± 0.9 cm³) groups (p = 0.794). The volume on the postoperative injured side did not differ significantly from that on the contralateral unaffected side in the 3D group, but these did differ significantly in the manual group. Postoperative VD also increased with the preoperative VD in the manual group (Pearson correlation coefficient = 0.548, p = 0.001), whereas there was no such association in the 3D group. The orbital volume restoration effect had superior surgical outcomes for large fractures using the customized orbital implant with 3D-printed templates compared with manual-bending implants. Full article