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1. Introduction

Bioprinting involves the deposition of cells and biomaterials to create functional tissues and organ
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models . It emerged from the broader field of additive manufacturing, which gained momentum
in the 1980s. Over time, various bioprinting technologies—such as inkjet, extrusion, and light-
based printing—have been developed to address specific needs in printing resolution, speed, and

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cell viability . Compared to traditional 2D cell cultures, bioprinting enables the fabrication of 3D
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tissue models that offer more physiologically relevant data for drug testing and may help reduce
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the reliance on animal experimentation . Additionally, bioprinting holds significant promise for
advancing regenerative medicine by enabling the creation of patient-specific tissue constructs and
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reducing dependence on conventional transplantation methods .

Bioprinting is increasingly focused on directly depositing bioinks onto patient tissues, enabling

rapid, on-site clinical interventions 7-10 . To support these in situ applications, portable and versatile
bioprinting systems are needed to navigate the human body—something conventional, bulky

benchtop bioprinters cannot achieve. Notably, laser-based bioprinters 11,12 reported for in-situ
applications have been limited to stationary systems without maneuverability. Conversely,

handheld bioprinters and robotic arms equipped with extrusion-based depositors have been used
to attain the maneuverability required for more complex in situ printing applications 9,13,14 .

Achieving reliable in situ bioprinting requires the printing head to adapt to physiological
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movements, as the body may still move under anesthesia due to breathing or involuntary motions .
This is critical for maintaining printing resolution and preventing tissue injury. Early in situ tissue

engineering efforts struggled to maintain print fidelity under dynamic conditions, resulting in low-
quality constructs 16,17 . However, with advances in sensor technologies and robotic control, motion

compensation has been explored as a solution. By integrating real-time motion compensation,

bioprinters can eventually adapt to patient movements, ensuring consistent high-quality prints.
Recent studies demonstrate that robotic systems with image-based motion compensation can be

used to counteract simulated physiological movements 14,18 .

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Among bioprinting techniques, drop-on-demand (DoD) methods—such as inkjet printing , laser-
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induced forward transfer (LIFT) 20-24 , and laser-induced flow focusing —are particularly well
suited for applications requiring non-contact biomaterial deposition. Recently, our lab introduced
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a DoD method termed laser-induced side transfer (LIST) for printing low- to moderate-viscosity
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