An easy and robust method of preparation of capsules for delivering probiotic bacteria by a 3D bioprinting

Probiotic bacteria such as Lactobacillus rhamnosus GG (LGG) play an important role in maintaining a healthy microbiota environment. Oral administration is the only way to deliver probiotic bacteria to the small intestine. Due to the harsh environment of the gastrointestinal tract, only a small proportion of probiotic bacteria can reach the target site, limiting their beneficial effects. Although many encapsulation techniques exist, the loss of bacterial cell viability, high cost, and low payload remain a major problem. In this work, we present a state-of-the-art microextrusion technique for encapsulating probiotic bacteria using a 3D bio-printer. Using a composite of sodium alginate, gelatin gel and LGG as bioink, we printed encapsulated LGG bacteria that were stable for 7 days. The production of the encapsulated bacteria was a very fast and simple process. We printed 120 probiotic capsules, each containing 108 CFU/ml, within 30 min. On microscopic examination of the LGG capsules, the encapsulated LGG bacteria were evenly distributed in the alginate-gelatin hydrogel. The bacteria in the capsules were viable and alive for 7 days at 4 °C and survived the harsh gastrointestinal fluid environment in vitro. This bioprinting method for encapsulating probiotic bacteria for their specific delivery in the gut could become a revolutionary method for industrial applications.