Biofabrication of a shape-stable auricular structure for the reconstruction of ear deformities

Bioengineering of the human auricle remains a significant challenge, where the complex and unique shape, the generation of high-quality neocartilage, and shape preservation are key factors. Future regenerative medicine–based approaches for auricular cartilage reconstruction will benefit from a smart combination of various strategies. Our approach to fabrication of an ear-shaped construct uses hybrid bioprinting techniques, a recently identified progenitor cell population, previously validated biomaterials, and a smart scaffold design. Specifically, we generated a 3D-printed polycaprolactone (PCL) scaffold via fused deposition modeling, photocrosslinked a human auricular cartilage progenitor cell–laden gelatin methacryloyl (gelMA) hydrogel within the scaffold, and cultured the bioengineered structure in vitro in chondrogenic media for 30 days. Our results show that the fabrication process maintains the viability and chondrogenic phenotype of the cells, that the compressive properties of the combined PCL and gelMA hybrid auricular constructs are similar to native auricular cartilage, and that biofabricated hybrid auricular structures exhibit excellent shape fidelity compared with the 3D digital model along with deposition of cartilage-like matrix in both peripheral and central areas of the auricular structure. Our strategy affords an anatomically enhanced auricular structure with appropriate mechanical properties, ensures adequate preservation of the auricular shape during a dynamic in vitro culture period, and enables chondrogenically potent progenitor cells to produce abundant cartilage-like matrix throughout the auricular construct. The combination of smart scaffold design with 3D bioprinting and cartilage progenitor cells holds promise for the development of clinically translatable regenerative medicine strategies for auricular reconstruction.

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First application of human auricular cartilage progenitor cells for bioprinting.

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Dual-printing of hybrid ear-shaped constructs with excellent shape fidelity over time.

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Strategy and design ensured adequate deposition of cartilage-like matrix throughout large auricular constructs.

Validation of low-cost smartphone-based thermal camera for diabetic foot assessment

AIMS

Infrared thermal imaging (IR) is not yet routinely implemented for early detection of diabetic foot ulcers (DFU), despite proven clinical effectiveness. Low-cost, smartphone-based IR-cameras are now available and may lower the threshold for implementation, but the quality of these cameras is unknown. We aim to validate a smartphone-based IR-camera against a high-end IR-camera for diabetic foot assessment.

METHODS

We acquired plantar IR images of feet of 32 participants with a current or recently healed DFU with the smartphone-based FLIR-One and the high-end FLIR-SC305. Contralateral temperature differences of the entire plantar foot and nine pre-specified regions were compared for validation. Intra-class correlations coefficient (ICC(3,1)) and Bland-Altman plots were used to test agreement. Clinical validity was assessed by calculating statistical measures of diagnostic performance.

RESULTS

Almost perfect agreement was found for temperature measurements in both the entire plantar foot and the combined pre-specified regions, respectively, with ICC values of 0.987 and 0.981, Bland-Altman plots' mean Δ = -0.14 and Δ = -0.06. Diagnostic accuracy showed 94% and 93% sensitivity, and 86% and 91% specificity.

CONCLUSIONS

The smartphone-based IR-camera shows excellent validity for diabetic foot assessment.