To fabricate the composite, researchers use custom melt electrospinning apparatus to heat a medical-grade biocompatible polymer called poly Ɛ-caprolactone (mPCL) to 103 C in a syringe. The mPCL is then extruded using a syringe pump, while an electrostatic field is created between the syringe needle tip and metal collector plate to create a stable mPCL jet. Mach3 motion control software facilitates movement of the collector plate and prints 0-90° scaffold architectures measuring up to 120 x 120 x 1 millimeters. Two 5 x 5 millimeter cylindrical samples are extracted from the scaffolds and stacked to a height of 2 millimeters, which is comparable to the thickness of human cartilage in the knee joint. Gelatin methacrylmide (GelMA) hydrogels are infused and crosslinked within the mPCL scaffolds to create a fibrous hydrogel composite, which is then seeded with human cartilage cells.

The result is a composite that approaches the stiffness and flexibility of cartilage and is conducive to cell proliferation and differentiation and ultimately, tissue regeneration. “This work is at the core of our 21st century intelligentsia in cartilage tissue engineering,” says Hutmacher.

CFRP Wheelchair 

Paralyzed people spend most of their days in wheelchairs, so why can’t they be both functional and attractive? Carbon Black System in Nairn, Scotland, sought to design a wheelchair that
met both requirements. Its new Carbon Black wheelchair uses more CFRP than any other wheelchair on the market, according to the company. It selected CFRP for many of the same reasons the material is used in sports cars: It’s lightweight, strong and stiff and can be easily molded into different shapes. It also looks sleek.

Each Carbon Black wheelchair is handmade in a facility that also produces body parts for Formula One race cars. The wheelchairs feature a high-modulus carbon fiber in a combination of woven and unidirectional prepreg fabrics. “The characteristics of the carbon fiber, linked with the unique laminate schedule, creates a strong chair with shock-absorbing characteristics,” says Paul Komoro, sales and marketing director for the company.