Tissues – From Banking to Engineering
How Scientists Are Building Spare Parts for the Human Body
A New Era of Medicine
Imagine a future where damaged organs could be replaced like mechanical parts in a car, where burn victims receive lab-grown skin instead of painful grafts, and where aging tissues are rejuvenated with biologically engineered alternatives.
This isn't science fiction—it's the emerging reality of tissue engineering, a revolutionary field that's transforming medicine from simply treating disease to actually rebuilding the human body.
The scope of this medical revolution recently expanded beyond Earth's atmosphere. In August 2025, researchers from the Wake Forest Institute for Regenerative Medicine launched a groundbreaking experiment to the International Space Station to test 3D-bioprinted liver tissue in microgravity 1 . This extraordinary mission highlights how far we've come from the early days of simply preserving tissues in banks to actively engineering living replacements.
This article will explore how tissue engineering is reshaping medicine, detail the fascinating science behind growing tissues, and examine how research in space could unlock new possibilities for patients on Earth.
From Banking to Engineering: A Paradigm Shift
The concept of "tissue banking"—preserving human tissues for later medical use—has been practiced for decades through blood banks, skin grafts for burn victims, and bone transplants. While valuable, this approach is fundamentally limited by donor availability, compatibility issues, and storage constraints. Tissue engineering represents a radical departure—instead of merely preserving what nature provides, we're learning to build with biology.
Living Cells
The biological building blocks that form functional tissue
Scaffold Materials
Structural frameworks that support tissue development
Biological Signals
Instructions that guide cell organization and function
At its core, tissue engineering combines living cells with specially designed scaffold materials and biological signals to create functional tissue constructs. Think of it like constructing a building: the scaffold provides the structural framework, the cells are the inhabitants, and the biological signals are the instructions that tell those inhabitants how to organize themselves 4 .
The potential impact is staggering. The global tissue engineering market, valued at $5.4 billion in 2025, is projected to reach $9.8 billion by 2030, growing at a compound annual growth rate of 12.8% . This growth reflects both medical need and technological advancement, particularly in addressing the challenges of an aging global population.
Global Tissue Engineering Market Projections (2024-2030)
| Year | Market Value (Billion USD) | Growth Rate | Key Drivers |
|---|---|---|---|
| 2024 | $4.8 | - | Base year |
| 2025 | $5.4 | 12.5% | Increased product approvals, technological advances |
| 2030 | $9.8 | 12.8% CAGR | 3D bioprinting, smart biomaterials, AI integration |
| 2033 | $10.2 (projection) | 11.6% CAGR | Expansion into emerging economies |
The Building Blocks: Scaffolds, Cells, and Signals
The Scaffold: Architecture for Life
Scaffolds serve as the foundational framework for engineered tissues, much like the wooden framework that supports a house under construction. These three-dimensional structures are typically made from biodegradable materials that gradually dissolve as the new tissue matures, eventually leaving only the natural tissue behind 4 .
Scaffold Requirements
- Porous structure for nutrient flow
- Biodegradable materials
- Mechanical stability
- Biocompatibility
Fabrication Methods
- Solvent Casting/Particulate Leaching
- Freeze Drying
- Gas Foaming
Creating effective scaffolds requires precise engineering. The materials must be porous enough to allow nutrients to reach the cells and waste products to escape, but stable enough to maintain their structure during tissue development. As one researcher beautifully analogizes, a scaffold without proper pores is "like a house without doors, windows, and staircases"—completely unusable 4 .
Cells: The Living Component
The second critical element comprises the living cells that will eventually form the functional tissue. These can come from various sources: a patient's own cells (avoiding rejection issues), donor cells, or—most promisingly—stem cells with the ability to develop into different cell types 5 .
A significant challenge in cell manufacturing is maintaining what scientists call "cell identity" and "potency"—ensuring that cells retain their specific characteristics and therapeutic capabilities during the expansion process 7 . Native tissues are remarkably heterogeneous, containing multiple cell types arranged in precise architectures. Recreating this complexity remains one of the field's greatest challenges.
Signals: Directing the Growth
Even with the right scaffold and cells, tissues need instructions to develop properly. Biological signals—including growth factors, mechanical stimuli, and increasingly, genetic instructions—provide the necessary guidance 9 . Researchers are exploring innovative approaches, including using CRISPR gene editing to program cells for specific regenerative applications 9 .
The Space Experiment: Growing Liver Tissue in Microgravity
Why Space?
The International Space Station (ISS) has become an unexpected but valuable laboratory for tissue engineering. Microgravity presents unique conditions that can overcome fundamental limitations faced by researchers on Earth.
On our planet, creating thick, complex tissues is challenging because gravity causes cells to settle unevenly, and maintaining oxygen and nutrient flow throughout large tissue structures requires sophisticated vascular networks that are difficult to engineer. In the weightless environment of space, cells distribute more evenly, and researchers hope this will lead to better-formed tissues 1 .
Mission Methodology: Step by Step
The investigation, sponsored by the ISS National Laboratory and launched on SpaceX's 33rd Commercial Resupply Services mission in August 2025, follows a carefully designed protocol 1 :
Pre-launch Preparation
3D bioprinting of gel-like liver tissue constructs with vascular channels
Transport to ISS
Launch via SpaceX Dragon spacecraft from Cape Canaveral
On-Orbit Experiment
Housed in Redwire Space's Multi-Use Variable-Gravity Platform
Analysis
Return to Earth for comparison with Earth-grown tissues
Expected Outcomes and Significance
The research team will assess multiple aspects of the space-grown tissues, including whether vascular cells correctly form linings in the blood vessel walls and whether the liver cells show enhanced function and maturity compared to their Earth-grown counterparts 1 .
Success could significantly advance efforts to create functional laboratory-grown tissues for drug testing and, eventually, transplantation. As James Yoo, the professor leading the investigation, notes: "This collaborative investigation has the potential to yield remarkable results... opening up new possibilities for medical treatments both on Earth and in space" 1 .
The Scientist's Toolkit: Essential Research Reagents
Creating engineered tissues requires specialized materials and reagents. The following table details key components used in tissue engineering research, such as in the ISS liver experiment:
Essential Research Reagents in Tissue Engineering
| Research Reagent | Function in Tissue Engineering | Examples/Specific Types |
|---|---|---|
| Biodegradable Polymers | Forms scaffold structure; degrades as tissue matures | PLGA (Poly(lactic-co-glycolic acid)), Polycaprolactone 4 8 |
| Stem Cells | Differentiates into various cell types; forms functional tissue | Embryonic Stem Cells (ESCs), human-induced Pluripotent Stem Cells (hiPSCs) 5 7 |
| Growth Factors | Biological signals that guide cell development and organization | Various proteins and peptides (e.g., E7 peptide for osteogenesis) 9 |
| Hydrogels | Provides 3D environment for cell encapsulation and growth | Hyaluronic acid-based hydrogels 8 |
| Endothelial Cells | Forms vascular networks for blood vessel development | Primary endothelial cells from vascular tissues 7 |
From Lab to Clinic: Approved Tissue-Engineered Products
While the space experiment represents cutting-edge research, tissue engineering has already produced FDA-approved clinical products. These pioneering therapies demonstrate the field's transition from theoretical concept to practical reality.
As of July 2025, the FDA's Office of Therapeutic Products has approved only four cell-based tissue engineering therapies, highlighting both the field's promise and the significant regulatory hurdles it faces 7 . These approved products primarily consist of avascular tissues with relatively simple structures, such as skin grafts and cartilage repairs, which are less complex than the vascularized tissues currently under development.
FDA-Approved Cell-Based Tissue Engineering Products (as of July 2025)
Skin Grafts
Burn treatment, wound healing
Cartilage Repair
Joint regeneration
Additional Products
Various applications
The approval process for these products involves rigorous evaluation of what the FDA terms "potency"—the specific ability of the cell product to produce intended therapeutic effects 7 . Manufacturers must demonstrate this potency at the moment of application and maintain it consistently across manufacturing lots, following "current good manufacturing practices" 7 .
Future Horizons and Challenges
The next decade promises remarkable advances in tissue engineering. Several cutting-edge technologies are poised to transform the field:
3D Bioprinting
Layer-by-layer deposition of cells and biomaterials to create precise tissue architectures .
Organ-on-a-Chip
Microfluidic devices containing engineered human tissues that mimic organ-level functions .
Smart Biomaterials
Materials that respond to environmental cues to guide tissue development .
AI Integration
AI algorithms to optimize scaffold designs and predict tissue development .
Challenges Ahead
- High Cost
- Regulatory Hurdles
- Ethical Considerations
Vascularization Challenge
Engineering complex solid organs requires solving the vascularization challenge—creating intricate blood vessel networks to sustain thick tissues. This is precisely why research like the ISS liver experiment is so critical to the field's advancement 1 .
Researchers are also exploring how traditional knowledge, such as active components in traditional Chinese medicine, might contribute to tissue engineering. For example, one team discovered that a component in goji berries (miR162a) improves osteoporosis, potentially opening new avenues for combining traditional and modern approaches 9 .
The Path From Preservation to Creation
The journey from tissue banking to tissue engineering represents one of the most significant transformations in modern medicine. We've moved from simply preserving what nature provides to actively understanding and applying the principles of tissue development to create new biological structures.
The ISS liver experiment symbolizes this transition—it's not merely about preserving tissue, but about creating conditions that enable better tissue formation than what we can currently achieve on Earth. As David Gobel of the Methuselah Foundation, which helped organize the NASA Vascular Tissue Challenge that spurred the Wake Forest research, notes: "By collaborating with NASA and the ISS National Lab to accelerate innovation, we're not only improving human health on Earth but also preparing for the challenges of space exploration and bolstering the future space industry" 1 .
As research continues, the day may come when organ transplant waiting lists are obsolete, replaced by laboratories that can create personalized replacement tissues on demand. From the early days of tissue banking to the current era of tissue engineering, we're witnessing the emergence of a new medical paradigm—one that doesn't just treat disease but actively regenerates the human body.
Article last updated: August 2025