A team of Spanish scientists has designed a bioreactor that allows to grow, in four weeks, human cartilage tissues in scaffolds generated by 3D printing. Likewise, said bioreactor allows real‑time monitoring through the analysis of ultrasonic signals. The team of researchers is composed of doctors, biologists, physicists and engineers led by the University of Granada (UGR).
Engineered cartilage tissue is at present one of the most promising treatments for articular cartilage pathologies, caused by ruptures and sports injuries, genetic factors or other diseases (such as some types of arthritis).
In this study, published in the journalSensors and Actuators B, 'scaffolds' of polylactic acid (a biocompatible and resorbable substance) were 3D‑printed and seeded with human chondrocytes (human cartilage cells) obtained from patients. Then, they were cultured in an ultrasound (US)‑integrated bioreactor.
The readings from the ultrasonic sensors were analyzed by numerical models of the ultrasound‑tissue interaction and by a stochastic treatment to infer the extracellular matrix (ECM) evolution. To reconstruct the velocity and attenuation from the recorded signals, the scientists combined a computational process (based on genetic algorithms on the biomechanics of the tissue) with the processing of the propagation of the wave.
The ultrasonic data were validated against evolution measurements of thein vitro3D chondrocyte cultures assessed by proliferation and morphological observations, qualitative and quantitative biochemical parameters and gene expression analysis.
The parameters reconstructed by the scientists from the ultrasonic monitoring (such as p‑wave velocity, attenuation, cell density changes) were proved useful to indirectly determine cell culture proliferation parameters in a non‑invasive manner.
The new US evaluation method developed is presented as a precise and non‑invasive procedure that can be automated and which provides real‑time information on the functionality of primary human chondrocytes. This method could monitor and evaluate, in a clinical context, the progression of the lesion after the treatment in patients with osteoarthritis.