Bioengineering

17 pages, 2104 KiB

Open AccessArticle

Rotational Projection Errors in Coronal Knee Alignment on Weight-Bearing Whole-Leg Radiographs: A 3D CT Reference Across CPAK Morphotypes

by Igor Strahovnik, Andrej Strahovnik and Samo Karel Fokter

Bioengineering 2025, 12(8), 794; https://doi.org/10.3390/bioengineering12080794 - 23 Jul 2025

Abstract

Whole-leg radiographs (WLRs) are widely used to assess coronal alignment before total knee arthroplasty (TKA), but may be inaccurate in patients with atypical morphotypes or malrotation. This study evaluated the discrepancy between WLR and 3D computed tomography (CT) scans across coronal plane alignment [...] Read more.

Whole-leg radiographs (WLRs) are widely used to assess coronal alignment before total knee arthroplasty (TKA), but may be inaccurate in patients with atypical morphotypes or malrotation. This study evaluated the discrepancy between WLR and 3D computed tomography (CT) scans across coronal plane alignment of the knee (CPAK) morphotypes and introduced a novel projection index—the femoral notch projection ratio (FNPR). In CPAK III knees, 19% of cases exceeded a clinically relevant threshold (>3° difference), prompting investigation of underlying projection factors. In 187 knees, coronal angles—including the medial distal femoral angle (MDFA°), medial proximal tibial angle (MPTA°), femoral mechanical angle (FMA°), and arithmetic hip–knee–ankle angle (aHKA°)—were measured using WLR and CT. Rotational positioning on WLR was assessed using FNPR and the patellar projection ratio (PPR). CPAK classification was applied. WLR systematically underestimated alignment, with the greatest bias in CPAK III (MDFA° + 1.5° ± 2.0°, p < 0.001). FNPR was significantly higher in CPAK III and VI (+1.9° vs. −0.3°, p < 0.001), indicating a tendency toward internally rotated limb positioning during imaging. The PPR–FNPR mismatch peaked in CPAK III (4.1°, p < 0.001), suggesting patellar-based centering may mask rotational malprojection. Projection artifacts from anterior osteophytes contributed to outlier measurements but were correctable. Valgus morphotypes with oblique joint lines (CPAK III) were especially prone to projection error. FNPR more accurately reflected rotational malposition than PPR in morphotypes prone to patellar subluxation. A 3D method (e.g., CT) or repeated imaging may be considered in CPAK III to improve surgical planning. Full article

(This article belongs to the Special Issue Musculoskeletal Bioengineering: Imaging and Computational Modeling in Biomechanics)

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14 pages, 835 KiB

Open AccessArticle

Evaluating Accuracy of Smartphone Facial Scanning System with Cone-Beam Computed Tomography Images

by Konstantinos Megkousidis, Elie Amm and Melih Motro

Bioengineering 2025, 12(8), 792; https://doi.org/10.3390/bioengineering12080792 - 23 Jul 2025

Abstract

Objectives: Facial soft tissue imaging is crucial in orthodontic treatment planning, and the structured light scanning technology found in the latest iPhone models constitutes a promising method. Currently, studies which evaluate the accuracy of smartphone-based three-dimensional (3D) facial scanners are scarce. This study [...] Read more.

Objectives: Facial soft tissue imaging is crucial in orthodontic treatment planning, and the structured light scanning technology found in the latest iPhone models constitutes a promising method. Currently, studies which evaluate the accuracy of smartphone-based three-dimensional (3D) facial scanners are scarce. This study compares smartphone scans with cone-beam computed tomography (CBCT) images. Materials and Methods: Three-dimensional images of 23 screened patients were captured with the camera of an iPhone 13 Pro Max and processed with the Scandy Pro application; CBCT scans were also taken as a standard of care. After establishing unique image pairs of the same patient, linear and angular measurements were compared between the images to assess the scanner’s two-dimensional trueness. Following the co-registration of the virtual models, a heat map was generated, and root mean square (RMS) deviations were calculated for quantitative assessment of 3D trueness. Precision was determined by comparing consecutive 3D facial scans of five participants, while intraobserver reliability was assessed by repeating measurements on five subjects after a two-week interval. Results: This study found no significant difference in soft tissue measurements between smartphone and CBCT images (p > 0.05). The mean absolute difference was 1.43 mm for the linear and 3.16° for the angular measurements. The mean RMS value was 1.47 mm. Intraobserver reliability and scanner precision were assessed, and the Intraclass Correlation Coefficients were found to be excellent. Conclusions: Smartphone facial scanners offer an accurate and reliable alternative to stereophotogrammetry systems, though clinicians should exercise caution when examining the lateral sections of those images due to inherent inaccuracies. Full article

(This article belongs to the Special Issue Orthodontic Biomechanics)

11 pages, 584 KiB

Open AccessSystematic Review

Artificial Intelligence for Non-Invasive Prediction of Molecular Signatures in Spinal Metastases: A Systematic Review

by Vivek Sanker, Sai Sanikommu, Alexander Thaller, Zhikai Li, Philip Heesen, Srinath Hariharan, Emil O. R. Nordin, Maria Jose Cavagnaro, John Ratliff and Atman Desai

Bioengineering 2025, 12(8), 791; https://doi.org/10.3390/bioengineering12080791 - 23 Jul 2025

Abstract

Background: Spinal metastases (SMs) are associated with poor prognosis and significant morbidity. We hypothesize that artificial intelligence (AI) models can enhance the identification and clinical utility of genetic and molecular signatures associated with SMs, improving diagnostic accuracy and enabling personalized treatment strategies. Methods: [...] Read more.

Background: Spinal metastases (SMs) are associated with poor prognosis and significant morbidity. We hypothesize that artificial intelligence (AI) models can enhance the identification and clinical utility of genetic and molecular signatures associated with SMs, improving diagnostic accuracy and enabling personalized treatment strategies. Methods: A systematic review of five databases was conducted to identify studies that used AI to predict genetic alterations and SMs outcomes. Accuracy, area under the receiver operating curve (AUC), and sensitivity were used for comparison. Data analysis was performed in R. Results: Eleven studies met the inclusion criteria, covering three different primary tumor origins, comprising a total of 2211 patients with an average of 201 ± 90 patients (range: 76–359 patients) per study. EGFR, Ki-67, and HER-2 were studied in ten (90.9%), two (18.1%), and one (9.1%) study, respectively. The weighted average AUC is 0.849 (95% CI: 0.835–0.863) and 0.791 (95% CI: 0.738–0.844) for internal and external validation of the established models, respectively. Conclusions: AI, through radiomics and machine learning, shows strong potential in predicting molecular markers in SMs. Our study demonstrates that AI can predict molecular markers in SMs with high accuracy. Full article

(This article belongs to the Section Biosignal Processing)

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15 pages, 2537 KiB

Open AccessArticle

Comparative Assessment of the Mechanical Response to Different Screw Dimensions in Scaphoid Fracture Fixation

by Esin Rothenfluh, Sambhav Jain, William R. Taylor and Seyyed Hamed Hosseini Nasab

Bioengineering 2025, 12(8), 790; https://doi.org/10.3390/bioengineering12080790 - 22 Jul 2025

Abstract

The scaphoid is the most commonly fractured carpal bone. Headless compression screws became the gold standard for fixation, but the ideal screw diameter remains debated. This study investigates the relative benefit of using a larger screw diameter to improve stability in typical scaphoid [...] Read more.

The scaphoid is the most commonly fractured carpal bone. Headless compression screws became the gold standard for fixation, but the ideal screw diameter remains debated. This study investigates the relative benefit of using a larger screw diameter to improve stability in typical scaphoid fractures. It also examines the effects of preload and screw length on mechanical behaviour. A finite element (FE) model of a mid-waist scaphoid fracture was created. Screws from Medartis (1.7 mm, 2.2 mm, and 3.0 mm diameter; 23 mm length) were placed along the longitudinal axis. Boundary and loading conditions matched prior studies. Interfragmentary displacement (IFD) and von Mises stress were compared across screw sizes. The effects of screw length and preload were also evaluated. Maximum in-plane IFD was 2.08 mm (1.7 mm screw), 0.53 mm (2.2 mm), and 0.27 mm (3.0 mm). The 1.7 mm screw exceeded the scaphoid’s average ultimate stress (60.51 MPa). Increasing preload reduced IFD, especially above 60 N. Screws longer than 1.5 times the mid-waist diameter offered no added benefit. Larger screws provide better biomechanical fracture stability. However, the gain from 2.2 mm to 3.0 mm is minor, while 1.7 mm screws lack sufficient strength. The 2.2 mm screw offers a good balance of stability and bone preservation, making it the preferred choice. Full article

(This article belongs to the Special Issue Advanced Engineering Technologies in Orthopaedic Research)

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12 pages, 732 KiB

Open AccessArticle

Umbilical Cord Tensile Strength Under Varying Strain Rates

by Maria Antonietta Castaldi, Pietro Villa, Alfredo Castaldi and Salvatore Giovanni Castaldi

Bioengineering 2025, 12(8), 789; https://doi.org/10.3390/bioengineering12080789 - 22 Jul 2025

Abstract

The tensile strength of the umbilical cord (UC) is influenced by its composition—including collagen, elastin, and hyaluronan—contributing to its unique biomechanical properties. This experimental in vitro study aimed to evaluate the UC’s mechanical behavior under varying strain rates and to characterize its viscoelastic [...] Read more.

The tensile strength of the umbilical cord (UC) is influenced by its composition—including collagen, elastin, and hyaluronan—contributing to its unique biomechanical properties. This experimental in vitro study aimed to evaluate the UC’s mechanical behavior under varying strain rates and to characterize its viscoelastic response. Twenty-nine UC specimens, each 40 mm in length, were subjected to uniaxial tensile testing and randomly assigned to three traction speed groups: Group A (n = 10) at 8 mm/min, Group B (n = 7) at 12 mm/min, and Group C (n = 12) at 16 mm/min. Four different parameters were analyzed: the ultimate tensile strength and its corresponding elongation, the elastic modulus defined as the slope of the linear initial portion of the stress–strain plot, and the elongation at the end of the test (at break). While elongation and elongation at break did not differ significantly between groups (one-way ANOVA), Group C showed a significantly higher ultimate tensile strength (p = 0.047). A linear relationship was observed between test speed and stiffness (elastic modulus), with the following regression equation: y = 0.3078e^4.425x. These findings confirm that the UC exhibits nonlinear viscoelastic properties and strain-rate-dependent stiffening, resembling non-Newtonian behavior. This novel insight may have clinical relevance during operative deliveries, where traction speed is often overlooked but may play a role in preserving cord integrity and improving neonatal outcomes. Full article

(This article belongs to the Section Biosignal Processing)

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18 pages, 3089 KiB

Open AccessArticle

High-Throughput Microfluidic Electroporation (HTME): A Scalable, 384-Well Platform for Multiplexed Cell Engineering

by William R. Gaillard, Jess Sustarich, Yuerong Li, David N. Carruthers, Kshitiz Gupta, Yan Liang, Rita Kuo, Stephen Tan, Sam Yoder, Paul D. Adams, Hector Garcia Martin, Nathan J. Hillson and Anup K. Singh

Bioengineering 2025, 12(8), 788; https://doi.org/10.3390/bioengineering12080788 - 22 Jul 2025

Abstract

Electroporation-mediated gene delivery is a cornerstone of synthetic biology, offering several advantages over other methods: higher efficiencies, broader applicability, and simpler sample preparation. Yet, electroporation protocols are often challenging to integrate into highly multiplexed workflows, owing to limitations in their scalability and tunability. [...] Read more.

Electroporation-mediated gene delivery is a cornerstone of synthetic biology, offering several advantages over other methods: higher efficiencies, broader applicability, and simpler sample preparation. Yet, electroporation protocols are often challenging to integrate into highly multiplexed workflows, owing to limitations in their scalability and tunability. These challenges ultimately increase the time and cost per transformation. As a result, rapidly screening genetic libraries, exploring combinatorial designs, or optimizing electroporation parameters requires extensive iterations, consuming large quantities of expensive custom-made DNA and cell lines or primary cells. To address these limitations, we have developed a High-Throughput Microfluidic Electroporation (HTME) platform that includes a 384-well electroporation plate (E-Plate) and control electronics capable of rapidly electroporating all wells in under a minute with individual control of each well. Fabricated using scalable and cost-effective printed-circuit-board (PCB) technology, the E-Plate significantly reduces consumable costs and reagent consumption by operating on nano to microliter volumes. Furthermore, individually addressable wells facilitate rapid exploration of large sets of experimental conditions to optimize electroporation for different cell types and plasmid concentrations/types. Use of the standard 384-well footprint makes the platform easily integrable into automated workflows, thereby enabling end-to-end automation. We demonstrate transformation of E. coli with pUC19 to validate the HTME’s core functionality, achieving at least a single colony forming unit in more than 99% of wells and confirming the platform’s ability to rapidly perform hundreds of electroporations with customizable conditions. This work highlights the HTME’s potential to significantly accelerate synthetic biology Design-Build-Test-Learn (DBTL) cycles by mitigating the transformation/transfection bottleneck. Full article

(This article belongs to the Section Cellular and Molecular Bioengineering)

18 pages, 4051 KiB

Open AccessArticle

Change in Mechanical Property of Rat Brain Suffering from Chronic High Intraocular Pressure

by Yukai Zeng, Kunya Zhang, Zhengyuan Ma and Xiuqing Qian

Bioengineering 2025, 12(8), 787; https://doi.org/10.3390/bioengineering12080787 - 22 Jul 2025

Abstract

Glaucoma is a trans-synaptic neurodegenerative disease, and the pathological increase in intraocular pressure (IOP) is a major risk factor of glaucoma. High IOP alters microstructure and morphologies of the brain tissue. Since mechanical properties of the brain are sensitive to the alteration of [...] Read more.

Glaucoma is a trans-synaptic neurodegenerative disease, and the pathological increase in intraocular pressure (IOP) is a major risk factor of glaucoma. High IOP alters microstructure and morphologies of the brain tissue. Since mechanical properties of the brain are sensitive to the alteration of the tissue microstructure, we investigate how varying durations of chronic elevated IOP alter brain mechanical properties. A chronic high IOP rat model was induced by episcleral vein cauterization with subconjunctival injection of 5-Fluorouracil. At 2, 4 and 8 weeks after induction, indentation tests were performed on the brain slices to measure mechanical properties in the hippocampus, lateral geniculate nucleus and occipital lobe of both hemispheres. Meanwhile, the brain’s microstructure was assessed via F-actin and myelin staining. Compared to the blank control group, the Young’s modulus decreased in all three brain regions in the highIOP experimental groups. F-actin fluorescence intensity and myelin area fraction were reduced in the hippocampus, while β-amyloid levels and tau phosphorylation were elevated in the experimental groups. Our study provides insight into Alzheimer’s disease pathogenesis by demonstrating how chronic high IOP alters the brain’s mechanical properties. Full article

(This article belongs to the Special Issue Bioengineering Strategies for Ophthalmic Diseases)

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Bioengineering, Volume 12, Issue 8 (August 2025) – 7 articles

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