Page 10 - IJB-9-5

International Journal of Bioprinting 3D printed edible bird’s nests

Figure 1. Producing replacements for EBN with the tissue-engineering methodology has both environmental and economic impacts. (A) The huge de-
mand for harvesting wild EBN in Southeast Asia damages the swiftlets’ home and the local ecological system. (B) Illustration of natural EBN’s formation,
containing both nutritional components secreted from the birds’ epithelial cells and hazard substances like microbes and heavy metals. (C) Scheme of re-
producing EBN formation with biomaterials, with a feeding layer (upper) of 3D-printed matrix culturing epithelial cells to produce functional ingredients
to be enriched in a receiving layer (lower) composed of food-grade materials. The receiving layer, representing the TeeBN, contains the essential nutritional
factors of natural EBN while avoiding heavy metal and microbial contaminations normally occurring in the latter.

supported by traditional Chinese medicine guarantee a USD dimensional (3D) biomaterials scaffolds to develop
6.5 billion market in China alone and a rising international functional tissue, with notable clinical breakthroughs in
market prices up to USD 6,600 per kilogram [2-5] . However, the cartilage, bone, and skin, among other tissue types .
[10]
the rapidly increasing demand for EBN has triggered In fact, it is often overlooked that the natural production
serious ecological and social issues. The annual export of EBN by swiftlets is also a physiological function of live
volume from major producing countries in Southeast Asia tissue. The bird’s saliva gland cells secrete saliva, which
exceeds 3,000 tons (Figure 1A). Excessive harvesting and solidifies to form the bowl nests adhering to the cave
unsustainable farming irreversibly damage the environment, wall for the birds’ habitation until being harvested for
rendering 4 million birds homeless and endangering certain human consumption (Figure 1B) . The nests contain
[1]
swallow species [6,7] . Also, natural EBNs on the market are abundant proteins and carbohydrates (>50% and >30%
often detected with toxic heavy metal salts and microbial dry weight, respectively) produced by salivary epithelial
contamination . Some products rich in nitrous acids and cells, which are believed to be the main nutritional
[8]
hence appearing red are portrayed and overpriced as the ingredients that underpin the healthcare effects of EBN .
[11]
rarest “blood bird’s nests,” with no scientific evidence except Utilizing the TE methodology to recapitulate the process
for potential adverse effects from sodium nitrite (NaNO ) of EBN production in vitro might open a new avenue for
2
[8,9] . Although government authorities and non-government engineering environmentally friendly EBN.
organizations have tried establishing artificial caves and large- The key to realizing this goal is to ensure the engineered
scale breeding, these attempts are regionally limited and loosely EBN contains the essential nutritional ingredients of
regulated. Producing EBN in an environmentally friendly and natural EBN in two main categories—(i) the structural
sustainable manner has emerged as a pressing challenge for macromolecules (e.g., glycans), which can be mimicked
both environmental protection and food security . with existing food-grade materials, and (ii) the small-
[6]
Tissue engineering (TE)—a medical technology to molecule metabolites and growth factors secreted by the
regenerate the human body—may provide an unexpected salivary gland, e.g., epithelial growth factor (EGF), sialic
answer to this challenge. TE promises to repair diseased acid, and N-acetylneuraminic acid, which are hard to
tissue by in vitro culturing mammalian cells in three- mimic and should ideally be released by living epithelial

Volume 9 Issue 5 (2023) 2 https://doi.org/10.18063/ijb.691