Logo: to the web site of Uppsala University

Additive manufacturing for fabrication of patient-specific oral and maxillofacial implants enables optimal fitting, significantly reducing surgery time and subsequent costs. However, it is still common to encounter hardware- or biological-related complications, specifically when radiation treatment is involved. For mandibular reconstruction plates, irradiated patients often experience plate loosening and subsequent plate exposure due to a decrease in the vascularity of the irradiated tissues. We hypothesize that an acceleration of the bone ingrowth prior to radiation treatment can increase the survival of such plates. In this work, a new design of a mandibular reconstruction plate is proposed to promote osseointegration, while providing the necessary mechanical support during healing. In this regard, six different Triply Periodic Minimal Surface (TPMS) structures were manufactured using laser-powder bed fusion. Three-point bending and in-vitro cell viability tests were performed. Mechanical testing demonstrated the ability for all structures to safely withstand documented biting forces, with favorable applicability for the Gyroid structure due its lower flexural modulus. Finally, cell viability tests confirmed high cell proliferation rate and good cell adhesion to the surface for all TPMS structures. Overall, the new design concept shows potential as a viable option for plates with improved functionality and higher survival rate.

Direct ink writing (DIW) is a promising technology for the fabrication of personalized bone grafts, as it enables the customization of their geometrical conformation with high reproducibility and is compatible with the use of self-setting calcium-deficient hydroxyapatite inks. However, the scaffolds obtained by DIW consist mostly of convex filaments, which is a limitation since concave surfaces are known to promote bone regeneration in vivo. In this work, we explore the use of triply periodic minimal surface (TPMS) designs in DIW of calcium phosphate self-hardening inks as a strategy to obtain scaffolds with controlled concave macropores. The limitations of the printing parameters with high ceramic-loaded inks using DIW resulted in only 20% nominal porosity for gyroid-, diamond-, and Schwarz-based structures. The inherent layered pores from TPMS geometries enabled concavities typically unattainable via DIW, bearing substantial implications for subsequent osteoinductive capabilities. Although the mechanical properties were lower in the TPMS-based scaffolds than in the orthogonal patterned ones, the blood permeability of TPMS-based structures was higher. The concave pore architecture enhanced the osteogenic potential of the biomimetic ceramic, increasing SaOs-2 cell adhesion, proliferation, differentiation, and mineralization.

Efficient cellular uptake of biomolecules, including genetic material, mRNA, proteins, and nanoparticles, requires novel approaches to overcome inherent cellular barriers. Here, the study investigates how nanotopographical cues from nanoporous surfaces impact the uptake efficiency by cells. The results demonstrate notable enhancements in cellular uptake efficiency across a range of vectors when cells are exposed to nanoporous surfaces. The uptake process is found to be dependent on the size and morphology of the nanopores, reaching a peak efficacy with blind pores of 400 nm in size. Enhanced genetic transduction on nanoporous surfaces are observed for multiple vectors, including lentiviruses, baculoviruses, and mRNA molecules. The versatile nature of this approach allows co-transfection of cells with multiple mRNA vectors. Moreover, the nanoporous platform is used for efficient and fast manufacturing of Chimeric Antigen Receptor (CAR)-T cells through lentiviral transduction. Furthermore, the study pinpoints macropinocytosis as the predominant mechanism driving increased cellular uptake induced by the nanoporous surfaces. The introduced method for enhancing genetic transduction of cells has applications in immunotherapy research, drug delivery, and cell engineering. Cellular uptake increases significantly by culturing cells on nanoporous surfaces. Nanopores, especially those sized at 400 nm, play a pivotal role in enhancing genetic transduction for various vectors like lentiviruses and mRNA. This versatile technique supports simultaneous co-transfection and expedites Chimeric Antigen Receptor (CAR)-T cell manufacturing. image

Minimally invasive spine treatments have been sought after for elderly patients with comorbidities suffering fromadvanced degenerative disc disease. Percutaneous cement discoplasty (PCD) is one such technique where cementis injected into a degenerated disc with a vacuum phenomenon to relieve patients from pain. Adjacent vertebralfractures (AVFs) are however an inherent risk, particularly for osteoporotic patients, due to the high stiffness ofthe used cements. While low-modulus cements have been developed for vertebroplasty through the addition oflinoleic acid, there are no such variations with a high-viscosity base cement, which is likely needed for thediscoplasty application.Therefore, a low-modulus polymethyl methacrylate was developed by the addition of 12%vol. linoleic acid toa high-viscosity bone cement (hv-LA-PMMA). Initial experimental validation of the cement was performed bymechanical testing under compression over a period of 24 weeks, after storage in 37 ◦C phosphate buffer saline(PBS) solution. Furthermore, cement extracts were used to evaluate residual monomer release and the cyto-toxicity of hv-LA-PMMA using fibroblastic cells.Relative to the base commercial cement, a significant reduction of Young’s modulus and compressive strengthof 36% and 42% was observed, respectively. Compression-tension fatigue tests at 5 MPa gave an average fatiguelimit of 31,078 cycles. This was higher than another low-modulus cement and comparable to the fatigueproperties of the disc annulus tissue. Monomer release tests showed that hv-LA-PMMA had a significantly higherrelease between 24 h and 7 days compared to the original bone cement, similarly to other low-modulus cements.Also, the control cement showed cytocompatibility at all time points of extract collection for 20-fold dilution,while hv-LA-PMMA only showed the same for extract collections at day 7. However, the 20-fold dilution wasneeded for both the control and the hv-LA-PMMA extracts to demonstrate more than 70% fibroblast viability atday 7.In conclusion, the mechanical testing showed promise in the use of linoleic acid in combination with a high-viscosity PMMA cement to achieve properties adequate to the application. Further testing and in vivo studies arehowever required to fully evaluate the mechanical performance and biocompatibility of hv-LA-PMMA forpossible future clinical application.

In principle, the measurement of mechanical property differences between cancer cells and their benign counterparts enables the detection, diagnosis, and classification of diseases. Despite the existence of various mechanophenotyping methods, the ability to perform high-throughput single-cell deformability measurements on liquid and/or solid tissue biopsies remains an unmet challenge within clinical settings. To address this issue, we present an ultrahigh-throughput viscoelastic microfluidic platform able to measure the mechanical properties of single cells at rates of up to 100,000 cells per second (and up to 10,000 cells per second in real time). To showcase the utility of the presented platform in clinical scenarios, we perform single-cell phenotyping of both liquid and solid tumor biopsies, cytoskeletal drug analysis, and identification of malignant lymphocytes in peripheral blood samples. Our viscoelastic microfluidic methodology offers opportunities for high-throughput, label-free single-cell analysis, with diverse applications in clinical diagnostics and personalized medicine.

Microfluidics has emerged as a promising approach for assessing cellular behavior in vitro, providing more physiologically relevant cell culture environments with dynamic flow and shear stresses. This study introduces the Universal Biomaterial-on-Chip (UBoC) device, which enables the evaluation of cell response on diverse biomaterial substrates in a 3D-printed microfluidic device. The UBoC platform offers mechanical stimulation of the cells and monitoring of their response on diverse biomaterials, enabling qualitative and quantitative in vitro analysis both on- and off-chip. Cell adhesion and proliferation were assessed to evaluate the biocompatibility of materials with different physical properties, while mechanical stimulation was performed to investigate shear-dependent calcium signaling in pre-osteoblasts. Moreover, the applicability of the UBoC platform in creating more complex in vitro models by culturing multiple cell types was demonstrated, establishing a dynamic multicellular environment to investigate cellular interfaces and their significance in biological processes. Overall, the UBoC presents an adaptable tool for in vitro evaluation of cellular behavior, offering opportunities for studying various biomaterials and cell interactions in microfluidic environments.

Nanodiamonds have emerged as promising agents for sensing and imaging due to their exceptional photostability and sensitivity to the local nanoscale environment. Here, we introduce a hybrid system composed of a nanodiamond containing nitrogen-vacancy center that is paired to a gold nanoparticle via DNA hybridization. Using multiphoton optical studies, we demonstrate that the harmonic mode emission generated in gold nanoparticles induces a coupled fluorescence emission in nanodiamonds. We show that the flickering of harmonic emission in gold nanoparticles directly influences the nanodiamonds' emissions, resulting in stochastic blinking. By utilizing the stochastic emission fluctuations, we present a proof-of-principle experiment to demonstrate the potential application of the hybrid system for super-resolution microscopy. The introduced system may find applications in intracellular biosensing and bioimaging due to the DNA-based coupling mechanism and also the attractive characteristics of harmonic generation, such as low power, low background and tissue transparency.

A requirement for clinical approval is verification of a biomaterial’s functionality and biocompatibility. However, discrepancies between in vitro and in vivo evaluations have been reported, possibly due in part to a lack of physiological relevance of typical in vitro culture set-ups. We introduce a Universal Biomaterial-on-Chip (UBoC), which is a microfluidics device that allows integration of biomaterials with varied shapes and properties and subsequent evaluation of in vitro performance under design considerations that resemble physiological conditions. In addition, UBoC operates with multifunctional modalities such as continuous perfusion, shear stress mechanostimulation and cell co-culture. The device is constructed using simple 3D printing and microfabrication techniques and its cell culture area resembles a 96-well plate (0.32 cm²). Successful cell adhesion and proliferation was observed on-chip on different materials (hydroxyapatite, titanium and fibrin) using fluorescence microscopy. Furthermore, device applicability for mechanostimulation was demonstrated through shear stimulation, where sensitivity of pre-osteoblasts to flow was captured via live Ca²⁺ imaging. Finally, the modularity of the UBoC platform for on-chip co-culture experiments was established after simple modifications of on-board fluidic arrangements. Overall, the UBoC presents a useful tool that augments existing in vitro testing strategies and enables thorough comparisons between biomaterials in tunable culture conditions.