Bioactive glasses are promising materials for bone scaffolds due to their ability to assist in tissue regeneration. When implanted in vivo, bioactive glasses can convert into hydroxyapatite, the main mineral constituent of human bone, and form a strong bond with the surrounding tissues, thus providing an advantage over polymer scaffold materials. Bone scaffold fabrication using additive manufacturing techniques can provide control over pore interconnectivity during fabrication of the scaffold, which helps in mimicking human trabecular bone. 13-93 glass, a third-generation bioactive material designed to accelerate the body's natural ability to heal itself, was used in the research described herein to fabricate bone scaffolds using the selective laser sintering (SLS) process. 13-93 glass mixed with stearic acid (as the polymer binder) by ball milling was used as the powder feedstock for the SLS machine. The fabricated green scaffolds underwent binder burnout to remove the stearic acid binder and were then sintered at temperatures between 675 °C and 695 °C. The sintered scaffolds had pore sizes ranging from 300 to 800 µm with 50% apparent porosity and an average compressive strength of 20.4 MPa, which is excellent for non-load bearing applications and among the highest reported for an interconnected porous scaffold fabricated with bioactive glasses using the SLS process. The MTT labeling experiment and measurements of MTT formazan formation are evidence that the rough surface of SLS scaffolds provides a cell-friendly surface capable of supporting robust cell growth.

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Optically transparent glass-ribbon composite panels were made by reinforcing a clear epoxy resin with soda-lime silicate glass ribbons, as opposed to using cylindrical fibers, of matching refractive index. Cross-ply (0/90 ) optically transparent glass-ribbon composite panels were made by stacking either 64 or 128 glass-ribbon layers and with tworibbon dimensions. The haze and light transmission were measured between 10 C and 52 C. Additionally, 610 mm  910 mm  18.7 mm flat windshields were made by laminating 1.9-mm thick (0 /90 ) 40 optically transparent glass-ribbon composite panels to clear polycarbonate panels in an autoclave. The haze and light transmission for the optically transparent glass-ribbon composite panels and for a prototype windshield were measured as a function of temperature while optical distortion was measured at room temperature (22 C) only for the windshield. The haze changed with temperature, with a minimum at the temperature where the refractive index of the glass ribbons and the polymer were equal. The lowest haze value was found for the widest ribbon, while the light transmission was almost constant in the temperature range of study.

Reconstruction of critical size defects in the load-bearing area has long been a challenge in orthopaedics. In the past, we have demonstrated the feasibility of using a biodegradable load-sharing scaffold fabricated from poly(propylene fumarate)/tricalcium phosphate (PPF/TCP) loaded with bone morphogenetic protein-2 (BMP-2) to successfully induce healing in those defects. However, there is limited osteoconduction observed with the PPF/TCP scaffold itself. For this reason, 13-93 bioactive glass scaffolds with local BMP-2 delivery were investigated in this study for inducing segmental defect repairs in a load-bearing region. Furthermore, a recent review on BMP-2 revealed greater risks in radiculitis, ectopic bone formation, osteolysis and poor global outcome in association with the use of BMP-2 for spinal fusion. We also evaluated the potential side effects of locally delivered BMP-2 on the structures of adjacent bones. Therefore, cylindrical 13-93 glass scaffolds were fabricated by indirect selective laser sintering with side holes on the cylinder filled with dicalcium phosphate dehydrate as a BMP-2 carrier. The scaffolds were implanted into critical size defects created in rat femurs with and without 10 μg of BMP-2. The x-ray and micro-CT results showed that a bridging callus was found as soon as three weeks and progressed gradually in the BMP group while minimal bone formation was observed in the control group. Degradation of the scaffolds was noted in both groups. Stiffness, peak load and energy to break of the BMP group were all higher than the control group. There was no statistical difference in bone mineral density, bone area and bone mineral content in the tibiae and contralateral femurs of the control and BMP groups. In conclusion, a 13-93 bioactive glass scaffold with local BMP-2 delivery has been demonstrated for its potential application in treating large bone defects.

Optically transparent ribbon-composite (OTRC) panels were made by reinforcing a clear polymer matrix with glass ribbons of matching refractive index. These panels had glass volume fraction up to 0.60 and tensile strength up to 772 MPa. Impact testing of 610 mm × 910 mm × 6 mm OTRC panels with a 0.45 kg projectile indicated two different failure modes at similar impact energies. One failure mode, corresponding to impact velocities from 883 to 913 km/h, was associated with crack initiation, which transitions to a large delamination zone. The second failure mode, corresponding to a 922 km/h impact velocity, is associated with crack formation as in a typical punch‐through failure. An ABAQUS finite element model was used to analytically predict the impact resistance of OTRC panels.