Three-Dimensional Printing and Its Potential to Develop Sensors for Cancer with Improved Performance.

Cancer is the second leading cause of death globally and early diagnosis is the best strategy to reduce mortality risk. Biosensors to detect cancer biomarkers are based on various principles of detection, including electrochemical, optical, electrical, and mechanical measurements. Despite the advances in the identification of biomarkers and the conventional 2D manufacturing processes, detection methods for cancers still require improvements in terms of selectivity and sensitivity, especially for point-of-care diagnosis. Three-dimensional printing may offer the features to produce complex geometries in the design of high-precision, low-cost sensors. Three-dimensional printing, also known as additive manufacturing, allows for the production of sensitive, user-friendly, and semi-automated sensors, whose composition, geometry, and functionality can be controlled. This paper reviews the recent use of 3D printing in biosensors for cancer diagnosis, highlighting the main advantages and advances achieved with this technology. Additionally, the challenges in 3D printing technology for the mass production of high-performance biosensors for cancer diagnosis are addressed.

Surgical guides for flapless dental implant placement and immediate definitive prosthesis installation by using selective laser melting and sintering for 3D metal and polymer printing: A clinical report.

Integration between the phases of computer-based guided dental implant surgery can be used to optimize oral rehabilitation. Two new surgical guides prepared by using the 3D metal and polymer printing technology are presented for immediate implant loading and definitive fixed prosthesis construction in flapless dental implant surgery. Nine implants and 2 fixed prostheses were installed in 2 completely edentulous adult patients by using a metallopolymer surgical guide with a metal central bar attached to a polymer seal or a metal guide. Virtual planning was used to design the 3D-printed surgical guides, which were then constructed by using selective laser sintering (SLM) and selective laser melting (SLS). The 3D-printed surgical guides oriented the surgical placement of the implants and were welded to the abutments and attached to the denture framework. The technique allowed implants and prostheses to be installed on the same day.

Soft Tissue Hybrid Model for Real-Time Simulations.

In this article, a recent formulation for real-time simulation is developed combining the strain energy density of the Spring Mass Model (SMM) with the equivalent representation of the Strain Energy Density Function (SEDF). The resulting Equivalent Energy Spring Model (EESM) is expected to provide information in real-time about the mechanical response of soft tissue when subjected to uniaxial deformations. The proposed model represents a variation of the SMM and can be used to predict the mechanical behavior of biological tissues not only during loading but also during unloading deformation states. To assess the accuracy achieved by the EESM, experimental data was collected from liver porcine samples via uniaxial loading and unloading tensile tests. Validation of the model through numerical predictions achieved a refresh rate of 31 fps (31.49 ms of computation time for each frame), achieving a coefficient of determination R2 from 93.23% to 99.94% when compared to experimental data. The proposed hybrid formulation to characterize soft tissue mechanical behavior is fast enough for real-time simulation and captures the soft material nonlinear virgin and stress-softened effects with high accuracy.

Delivery of Human Adipose Stem Cells Spheroids into Lockyballs.

Adipose stem cells (ASCs) spheroids show enhanced regenerative effects compared to single cells. Also, spheroids have been recently introduced as building blocks in directed self-assembly strategy. Recent efforts aim to improve long-term cell retention and integration by the use of microencapsulation delivery systems that can rapidly integrate in the implantation site. Interlockable solid synthetic microscaffolds, so called lockyballs, were recently designed with hooks and loops to enhance cell retention and integration at the implantation site as well as to support spheroids aggregation after transplantation. Here we present an efficient methodology for human ASCs spheroids biofabrication and lockyballs cellularization using micro-molded non-adhesive agarose hydrogel. Lockyballs were produced using two-photon polymerization with an estimated mechanical strength. The Young's modulus was calculated at level 0.1362 +/-0.009 MPa. Interlocking in vitro test demonstrates high level of loading induced interlockability of fabricated lockyballs. Diameter measurements and elongation coefficient calculation revealed that human ASCs spheroids biofabricated in resections of micro-molded non-adhesive hydrogel had a more regular size distribution and shape than spheroids biofabricated in hanging drops. Cellularization of lockyballs using human ASCs spheroids did not alter the level of cells viability (p > 0,999) and gene fold expression for SOX-9 and RUNX2 (p > 0,195). The biofabrication of ASCs spheroids into lockyballs represents an innovative strategy in regenerative medicine, which combines solid scaffold-based and directed self-assembly approaches, fostering opportunities for rapid in situ biofabrication of 3D building-blocks.

A selective laser sintering prototype guide used to fabricate immediate interim fixed complete arch prostheses in flapless dental implant surgery: Technique description and clinical results.

STATEMENT OF PROBLEM: Extensive occlusal adjustments and misfit of the prosthesis to prosthetic components are frequent problems related to fixed interim prosthesis fabrication with immediate dental implant loading. PURPOSE: The purpose of this clinical trial was to evaluate a prosthetic guide made with a rapid prototype model based on virtual surgical planning. This prosthetic guide was used to fabricate fixed interim prostheses that would allow immediate implant loading after computer-guided implant installation. MATERIAL AND METHODS: Nine interim prostheses were made for 9 participants with complete maxillary or mandibular edentulism. The virtual prosthetic guide was planned using computer-assisted design (CAD) software and was fabricated with rapid prototyping equipment (selective laser sintering). The prosthetic guide had 3 portions: the occlusal portion, which had occlusal registration; the connection portion, which had the information of the position and angulation of the abutment/implant projection; and the mucosa portion, which had the registration of the alveolar mucosa architecture. The prosthetic guide was used by a dental technician to fabricate prostheses. A single trained examiner evaluated the passive fit of the interim prostheses, the average time required for installing the interim prosthesis and for occlusal adjustments, the satisfaction of the patient with the prosthesis; and the screws, torque, occlusion, and prosthesis status. RESULTS: Passive fit was achieved between the prosthetic components and prostheses in 7 participants. The average time required for installing the fixed interim prostheses was 64.44 minutes. All participants reported being more pleased with the fixed interim prosthesis than with the prosthesis worn before implant placement. Prosthesis fractures were observed in 3 participants (2 in the maxilla and 1 in the mandible); all fractures occurred 3 months or more after delivery. No further complication was observed during 6 months of follow-up. CONCLUSIONS: The prosthetic guide enabled fabrication of interim immediate prostheses that were easily seated and adjusted to accommodate any shifts in implant position occurring during computer-guided surgery. Immediate implant loading could be achieved in a reasonable operative time.

Burr-like, laser-made 3D microscaffolds for tissue spheroid encagement.

The modeling, fabrication, cell loading, and mechanical and in vitro biological testing of biomimetic, interlockable, laser-made, concentric 3D scaffolds are presented. The scaffolds are made by multiphoton polymerization of an organic-inorganic zirconium silicate. Their mechanical properties are theoretically modeled using finite elements analysis and experimentally measured using a Microsquisher(®). They are subsequently loaded with preosteoblastic cells, which remain live after 24 and 72 h. The interlockable scaffolds have maintained their ability to fuse with tissue spheroids. This work represents a novel technological platform, enabling the rapid, laser-based, in situ 3D tissue biofabrication.