Additive manufacturing changed how engineers design and fabricate physical objects. It also opened a set of questions in biomedical research that mechanical engineers are particularly positioned to work on. When the material being printed is not plastic or metal but a cell-laden hydrogel, and when the structure being built is intended to sustain living tissue, the demands on the fabrication process shift substantially. Justin Jadali, a mechanical engineering researcher at Yale University, sits at exactly that intersection — bringing years of additive manufacturing experience to bear on one of the core challenges in tissue engineering: building constructs with functional vascular networks.
A Background in Additive Manufacturing That Predates the Research
Jadali’s engagement with additive manufacturing is not incidental to his current research — it predates it by years. Long before he entered Yale’s M.S. program in Mechanical Engineering and Materials Science, he was working with 3D printers in a hands-on capacity. He volunteered at his middle school to teach students to use 3D printers, an early demonstration of both technical fluency and an interest in passing that fluency on to others.
At UCLA, where he completed his B.S. in Mechanical Engineering, additive manufacturing is part of the engineering curriculum — covering design for manufacturing, prototyping workflows, and the material properties that govern how printed parts behave. For mechanical engineering students, the 3D printer is a standard tool. The question Jadali eventually brought to Yale was what happens when you apply that same fabrication discipline to biological systems, where the tolerances, the materials, and the stakes are categorically different.
What Bioprinting Actually Requires
The term “bioprinting” encompasses a range of techniques, but the underlying challenge is consistent: depositing biological materials — cells, hydrogels, growth factors — in precise three-dimensional configurations that support tissue formation and, eventually, tissue function.
This is more difficult than printing with conventional engineering materials for several reasons. Biological materials are mechanically weak, sensitive to processing conditions, and have narrow tolerance windows for temperature, pH, and shear stress. Cells embedded in bioinks must survive the printing process, maintain viability in the printed structure, and receive adequate nutrients and oxygen to proliferate. That last requirement is the central problem in tissue engineering at any meaningful scale: without a vascular network to deliver nutrients and remove waste, cells in thick constructs die before the tissue can mature.
Jadali’s current research addresses this problem directly. His work involves studying microvessel formation in both 3D gels and bioprinted skin constructs — examining how material properties and fabrication parameters influence the self-assembly of vessel-like structures that could eventually support thick, clinically relevant engineered tissue.
Alginate Microparticles as a Fabrication Strategy
One approach to promoting vascularization in engineered constructs involves incorporating bioactive microparticles into the construct during fabrication. Jadali’s research focuses on alginate-based microparticles — small, crosslinked hydrogel beads that can be embedded within a larger tissue construct and engineered to influence the behavior of surrounding cells.
Alginate is a polysaccharide derived from brown algae. It crosslinks readily in the presence of divalent cations, forming stable hydrogel networks with tunable mechanical properties. That tunability is what makes it useful as a biomaterial: by adjusting the type of crosslinking ion, the concentration of the alginate solution, and the fabrication method, researchers can produce microparticles with different stiffness profiles, degradation rates, and ion-release behaviors.
Jadali’s current experiments compare calcium crosslinking and zinc crosslinking in alginate microparticles. Calcium and zinc produce different network structures and release different ionic species into the surrounding environment — differences that affect how endothelial cells, pericytes, and fibroblasts respond to the particles and, consequently, how microvessel networks self-assemble in the surrounding gel matrix.
The fabrication of consistent, well-characterized microparticles is itself an engineering problem. Particle size distribution, crosslink density, and batch-to-batch reproducibility all influence downstream experimental outcomes. Jadali’s approach to this problem reflects his mechanical engineering training: develop rigorous standard operating procedures, document every variable, and treat the fabrication process as a system to be optimized, not just a protocol to be followed.
From 3D Gels to Bioprinted Skin Constructs
The transition from studying microvessel formation in 3D gels to studying it in bioprinted skin constructs represents a shift in fabrication complexity. A 3D gel is a relatively simple system — cells and particles are mixed into a hydrogel precursor and allowed to solidify. A bioprinted construct involves layer-by-layer deposition of materials with defined spatial architecture, requiring the fabrication process itself to preserve cell viability, maintain structural fidelity, and produce a construct whose geometry and composition can be systematically varied.
For a researcher with an additive manufacturing background, the bioprinted construct is the more natural context. The questions it raises — about print resolution, material rheology, cell distribution within the bioink, and how the printed architecture influences what happens biologically — are engineering questions as much as biology questions. They require someone who can think about the fabrication process and the biological outcome simultaneously.
Jadali’s positioning at this intersection is the product of deliberate preparation. The additive manufacturing fluency he developed before graduate school, the biology and organic chemistry he completed at UCLA alongside his engineering degree, and the wet-lab skills he has built at Yale — cell culture, microscopy, particle characterization — combine into a research profile that is equipped to work on the fabrication side and the biology side of the same problem.
Why Skin Constructs Are a Meaningful Research Focus
Skin is among the most studied tissues in bioengineering, for practical reasons. It is the body’s largest organ, it is frequently damaged through injury and disease, and it is accessible — meaning constructs developed for skin applications can be tested and evaluated more readily than those targeting internal organs.
The vascularization challenge in bioengineered skin is well-established. Thin skin grafts can survive by diffusion alone, but thicker constructs — those capable of replacing the full depth of skin lost in serious burns or chronic wounds — require a vascular network to sustain cell viability. Current clinical approaches to skin replacement have significant limitations, and the development of fully vascularized, bioengineered skin constructs remains an active and unresolved research problem.
Studying how microparticle properties influence microvessel self-assembly in bioprinted skin constructs is a contribution to that problem. If the relationship between alginate crosslinking chemistry and vascular network formation can be characterized, it provides a design parameter — something a fabricator can adjust to influence a biological outcome. That translation from material property to tissue behavior is precisely the kind of insight that moves tissue engineering research closer to clinical relevance.
The Engineer’s Contribution to a Biology Problem
There is a version of tissue engineering research that proceeds primarily from the biology — starting with what cells do and working backward toward materials and fabrication methods that support it. There is another version that proceeds from the fabrication — starting with what can be built and asking what biology that structure enables.
Jadali’s research sits closer to the second approach, not because the biology is secondary but because the engineering lens is where his preparation is deepest. His years of additive manufacturing experience, his training in materials behavior, and his systematic approach to experimental design position him to ask fabrication-driven questions with genuine biological consequence.
For a field where the translation from bench research to clinical application has been slower than the underlying science warrants, that engineering orientation is a relevant contribution. Constructs that cannot be reliably fabricated cannot be reliably tested. Materials whose properties cannot be precisely controlled cannot be systematically optimized. Experiments that cannot be reproduced cannot be built upon. The engineering infrastructure of tissue engineering research matters — and Jadali is building it deliberately.
About Justin Jadali
Justin Jadali is a mechanical engineer and biomedical engineering researcher with a focus on biomaterials, additive manufacturing, and tissue vascularization. He holds three Associate of Science degrees from Irvine Valley College and a B.S. in Mechanical Engineering from UCLA (Class of 2025). He is currently completing his M.S. in Mechanical Engineering and Materials Science at Yale University, where his research investigates alginate microparticle fabrication, calcium and zinc crosslinking systems, and microvessel self-assembly in 3D gels and bioprinted skin constructs. He serves as a Teaching Assistant for the Yale Mechanical Engineering Capstone and is based in New Haven, Connecticut.