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← Theoretical 1

Q13 — 3D Skin Substitute — Layered Tissue Engineering

Theoretical 1 Real exam question — full text reproduced under IBO's CC BY-NC-SA 4.0 license
Recombinant DNA & Biotechnology Techniques Human Integumentary System

For engineered tissue to survive in vivo it needs to be vascularized. Current approaches include incorporating adipose tissue-derived microvascular fragments, iPSC-derived endothelial cells, 3D bioprinting, and a layer-by-layer approach. The figure shows a multicellular 3D skin substitute assembled by interspersing three types of differentiated cells with thin layers of extracellular matrix film (fibronectin + gelatin), followed by several days of air-liquid interface culturing (Figure A). Figures B–D show staining outcomes: B — Masson’s trichrome (highlights collagen fibers), C — antibodies against laminin, D — antibodies against PECAM1 (an endothelial marker).

Figure showing the 3D skin substitute assembly (A) and four stained cross-sections (B: Masson’s trichrome with numbered layers 1-4, C: laminin, D: PECAM1) with red arrows marking features of interest. A: assembly of the 3D skin substitute. B: Masson’s trichrome staining, with layers 1–4 labelled. C: laminin staining (red arrows). D: PECAM1 staining (red arrows).

Using the information and figures, determine whether the following statements are true or false:

A. Layer 1 corresponds to the lamina of basal membrane.
B. Red arrows in Fig.C point to a newly formed vasculature.
C. Endothelial cells and fibroblasts are the key components of layer 4.
D. Keratinocytes and laminin are major components of layer 3.
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Question reproduced from IBO 2022, Theoretical Paper 1, licensed under CC BY-NC-SA 4.0 — attributed to the International Biology Olympiad. Open the full exam PDF · Community solutions (unofficial)