Turning a Mosquito Proboscis into a Micrometer-Scale 3D Printing Tool

3D necroprinting is a biohybrid manufacturing approach that repurposes biological structures from deceased organisms as functional components in 3D printing. Rather than merely drawing inspiration from biological forms, this strategy directly integrates existing biological materials into engineered systems. A striking example is the use of the female mosquito proboscis.

The dispense tip is a critical component in applications ranging from biomedical experiments and drug delivery to 3D bioprinting, where precise control of fluid flow is essential. Conventional engineered dispense tips are typically made from metals or plastics, which are costly and nonbiodegradable, contributing to environmental burden. Moreover, as their dimensions are reduced to the tens-of-micrometers scale, fabrication complexity and cost increase substantially, raising the barrier for high-resolution applications.

In contrast, nature offers a wide variety of highly refined microfluidic delivery structures. Insect proboscides, plant xylem vessels, and animal stingers all exhibit optimized geometries and material properties. Through long evolutionary refinement, these structures are capable of transporting fluids, penetrating substrates, and extracting liquids at extremely small scales, while maintaining both mechanical strength and flexibility.

The female mosquito proboscis is particularly notable due to its integrated multilayer structure. The outer sheath, known as the labium, encloses a fascicle composed of multiple needle-like elements, including the labrum and hypopharynx etc. Together, these components form a sealed, elongated microchannel. This channel has an inner diameter of approximately 20 to 25 μm, significantly smaller than most commercially available dispense tips, while maintaining sufficient stiffness and a manageable length of about 2 mm for practical operation.

Mosquito proboscis structure. Mx: maxilla; M: mandible; H: hypopharynx（圖片來源：Choo YM et al. (2015)，採用 CC BY 4.0 授權）

During blood feeding, a mosquito must penetrate the skin, locate blood vessels, and extract blood. This process requires the proboscis to withstand mechanical stress while efficiently transporting non-Newtonian fluids. These characteristics make it inherently well suited for engineering applications. In this work, the biological structure was integrated into a custom-built 3D printing system by mounting the mosquito proboscis at the outlet of a conventional dispense tip, creating a continuous fluid pathway.

3D printer integrated with a mosquito proboscis（圖片來源：Puma J et al. (2025).，採用 CC BY-NC 4.0 授權）

Real setup of the 3D printer（圖片來源：Puma J et al. (2025).，採用 CC BY-NC 4.0 授權）

Experimentally, this biological nozzle enabled high-resolution printing of various structures, including honeycomb geometries, maple leaf patterns, and cell-laden scaffolds. The printed filament widths ranged from approximately 18 to 28 μm, outperforming standard commercial dispense tips and approaching the capabilities of glass-pulled micropipettes, which are significantly more expensive and fragile.

Printed results（圖片來源：Puma J et al. (2025).，採用 CC BY-NC 4.0 授權）

A key challenge of this approach lies in maintaining stable printing conditions. Two primary failure modes were identified. The first arises from clog-induced overpressure at the outlet. For shear-thinning materials, once the ink exits the nozzle and loses shear stress, it becomes more solid-like, leading to accumulation and blockage. As pressure builds up, the nozzle eventually ruptures. The second failure mode is associated with high-viscosity materials. When the apparent viscosity is too high, greater backpressure is required to sustain flow, causing excessive stress near the inlet and resulting in rupture.

Pressure testing quantified the mechanical limits of the mosquito proboscis. The average burst pressure was approximately 60 kPa, and stress analysis indicated a circumferential stress limit of about 708 kPa. Although this strength is far lower than that of metals, it is sufficient for microscale printing under controlled conditions. Stable operation requires careful matching of ink extrusion speed and nozzle movement speed. Excessive extrusion leads to accumulation and clogging, while insufficient extrusion produces discontinuous filaments. Optimal performance is achieved when these parameters are balanced within a defined ratio, yielding uniform and continuous structures.

Beyond structural fabrication, this technique also shows promise in biomedical applications. Bioprinting experiments using materials containing cancer cells and red blood cells demonstrated a post-printing cell viability of approximately 86%, indicating effective mitigation of shear-induced damage. Additionally, the compliant nature of the biological nozzle reduces substrate damage, suggesting potential applications in drug delivery and tissue engineering.

Nevertheless, biological materials introduce inherent limitations, including shorter lifespan, sensitivity to storage conditions, and variability between individual samples. Experiments showed that the proboscis remains functional for approximately 9 days under ambient conditions, and for over a year when stored at low temperatures. With further refinement, this approach has the potential to reduce manufacturing costs and decrease reliance on nonbiodegradable materials, offering a new direction for sustainable and biointegrated engineering.

Video:

https://www.youtube.com/watch?v=abM85B1bWnY

Author: Shui-Ye You

Reference:

1. Choo YM et al. (2015). Multitasking roles of mosquito labrum in oviposition and blood feeding. Frontiers in Physiology.

2. Puma J et al. (2025). 3D necroprinting: Leveraging biotic material as the nozzle for 3D printing. Science Advances.