Tissue engineering is a rapidly advancing field that aims to create functional living tissues and organs for therapeutic applications. But how exactly is this possible? The answer lies in the use of PLGA-based scaffolds.
Tissue engineering, biotechnology lab – illustrative photo. Image credit: NIH NCI
In this article, we will explore the advantages of PLGA-based scaffolds in tissue engineering and how they are revolutionizing the field. From bone regeneration to skin tissue repair, the potential applications of this technology are vast and exciting. Let's dive into the details and see how PLGA-based scaffolds are advancing the future of medicine.
PLGA-based scaffolds: fabrication and characterization
One of the key steps in tissue engineering is to fabricate and characterize scaffolds that can support cell growth and tissue regeneration. Scaffolds are three-dimensional structures that provide physical and chemical cues for cells to attach, proliferate and differentiate into functional tissues and organs. Scaffolds should have certain properties, such as biodegradability, biocompatibility, porosity, mechanical strength, surface properties, etc., depending on the specific tissue or organ of interest.
PLGA is a suitable material for tissue engineering scaffolds because it has many desirable properties, such as:
- Biodegradability: PLGA can degrade by hydrolysis into lactic and glycolic acids, which are natural metabolites that can be eliminated by the body. The degradation rate of PLGA can be controlled by varying the copolymer ratio, molecular weight and crystallinity of the polymer.
- Biocompatibility: PLGA has been approved by the FDA for various clinical uses and has shown minimal toxicity and inflammation in vivo. The biocompatibility of PLGA can be further improved by modifying its surface with bioactive molecules or coatings.
- Tunability: PLGA can be fabricated using different techniques to create scaffolds with different shapes, sizes, architectures and properties. The tunability of PLGA allows for the customization of scaffolds for different tissues and organs.
Some examples of how PLGA-based scaffolds can be fabricated using different techniques are:
- Porogen leaching: This technique involves mixing PLGA with a porogen material, such as salt, sugar or gelatin, and then removing the porogen material by dissolving or melting it. This creates a porous scaffold with interconnected pores that allow for cell infiltration and nutrient exchange.
- Gas foaming: This technique involves exposing PLGA to high-pressure gas, such as CO2 or N2, and then releasing the gas rapidly. This creates a porous scaffold with closed pores that can be opened by further processing, such as solvent exchange or freeze-drying.
- Phase separation: This technique involves dissolving PLGA in a solvent, such as dichloromethane or acetone, and then adding a non-solvent, such as water or ethanol. This creates a phase separation between the polymer-rich and polymer-poor phases, which can be solidified by cooling or evaporation. This creates a porous scaffold with fibrous or sponge-like structures that can be controlled by varying the polymer concentration, solvent ratio and temperature.
- Electrospinning: This technique involves applying a high-voltage electric field to a polymer solution or melt, such as PLGA dissolved in chloroform or hexafluoroisopropanol. This creates a jet of polymer that is stretched and collected on a grounded collector. This creates a porous scaffold with nanofibers that mimic the natural extracellular matrix of various tissues and organs.
After fabrication, PLGA-based scaffolds can be characterized using different methods to evaluate their physical, chemical and biological properties. Some examples of how PLGA-based scaffolds can be characterized using different methods are:
- Scanning electron microscopy (SEM): This method involves scanning a focused beam of electrons over the surface of the scaffold and detecting the secondary electrons emitted by the scaffold. This creates an image of the surface morphology and topography of the scaffold, which can reveal its pore size, porosity, fiber diameter, etc.
- Micro-computed tomography (µCT): This method involves scanning a beam of X-rays over the scaffold and detecting the attenuation of the X-rays by the scaffold. This creates an image of the internal structure and architecture of the scaffold, which can reveal its pore size distribution, pore connectivity, porosity, etc.
- Mechanical testing: This method involves applying a force or deformation to the scaffold and measuring its response. This can reveal its mechanical properties, such as stiffness, strength, elasticity, etc., which can affect its stability and functionality in vivo.
- Surface characterization: This method involves analyzing the surface chemistry and properties of the scaffold using various techniques, such as contact angle measurement, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), etc. This can reveal its surface hydrophilicity/hydrophobicity, functional groups, coatings, etc., which can affect its cell adhesion and biocompatibility.
The fabrication and characterization of PLGA-based scaffolds are important steps in tissue engineering because they determine the suitability and performance of scaffolds for different tissues and organs. By using different techniques and methods, PLGA-based scaffolds can be tailored to meet the specific requirements and challenges of each tissue and organ.
PLGA-based scaffolds: examples and applications
The main applications of tissue engineering is to use scaffolds to support cell growth and tissue regeneration for different tissues and organs. Scaffolds should provide a suitable microenvironment for cells to attach, proliferate and differentiate into functional tissues and organs. Scaffolds should also match the shape, structure and function of the natural tissues and organs.
PLGA-based scaffolds can be used for different tissues and organs because they have many advantages, such as:
- Versatility: PLGA-based scaffolds can be fabricated using different techniques to create scaffolds with different shapes, sizes, architectures and properties. PLGA-based scaffolds can also be modified or combined with other materials or factors to enhance their performance and functionality.
- Biodegradability: PLGA-based scaffolds can degrade by hydrolysis into lactic and glycolic acids, which are natural metabolites that can be eliminated by the body. The degradation rate of PLGA-based scaffolds can be controlled by varying the copolymer ratio, molecular weight and crystallinity of the polymer. The degradation products of PLGA-based scaffolds can also act as acidic microenvironments that can stimulate cell growth and tissue regeneration.
- Biocompatibility: PLGA-based scaffolds have been approved by the FDA for various clinical uses and have shown minimal toxicity and inflammation in vivo. The biocompatibility of PLGA-based scaffolds can be further improved by modifying their surface with bioactive molecules or coatings.
Some examples of how PLGA-based scaffolds can be used for different tissues and organs are:
- Bone: Bone is a hard and rigid tissue that supports the body structure and protects the vital organs. Bone tissue engineering aims to create new bone tissue or repair bone defects caused by diseases, injuries or aging. PLGA-based scaffolds can be used for bone tissue engineering because they can provide mechanical support and osteoconductive cues for bone cells. PLGA-based scaffolds can also be modified or combined with other materials or factors to enhance their osteogenic potential, such as calcium phosphate, hydroxyapatite, collagen, bone morphogenetic proteins, etc.
- Cartilage: Cartilage is a soft and elastic tissue that covers the ends of bones and provides cushioning and lubrication for joints. Cartilage tissue engineering aims to create new cartilage tissue or repair cartilage defects caused by diseases, injuries or aging. PLGA-based scaffolds can be used for cartilage tissue engineering because they can provide physical support and chondroconductive cues for cartilage cells. PLGA-based scaffolds can also be modified or combined with other materials or factors to enhance their chondrogenic potential, such as gelatin, hyaluronic acid, chondroitin sulfate, transforming growth factor beta, etc.
- Skin: Skin is a complex and multifunctional tissue that covers the body surface and provides protection, sensation and thermoregulation. Skin tissue engineering aims to create new skin tissue or repair skin defects caused by diseases, injuries or aging. PLGA-based scaffolds can be used for skin tissue engineering because they can provide structural support and biocompatible cues for skin cells. PLGA-based scaffolds can also be modified or combined with other materials or factors to enhance their epidermal and dermal potential, such as keratinocytes, fibroblasts, collagen, elastin, growth factors, etc.
- Nerve: Nerve is a specialized tissue that transmits electrical signals between the brain and the rest of the body. Nerve tissue engineering aims to create new nerve tissue or repair nerve defects caused by diseases, injuries or aging. PLGA-based scaffolds can be used for nerve tissue engineering because they can provide physical guidance and neuroconductive cues for nerve cells. PLGA-based scaffolds can also be modified or combined with other materials or factors to enhance their neurogenic potential, such as nerve growth factor, brain-derived neurotrophic factor, Schwann cells, etc.
These are just some examples of how PLGA-based scaffolds can be used for different tissues and organs. There are many more possibilities and opportunities for using PLGA-based scaffolds for tissue engineering. By using PLGA-based scaffolds, we can hope to create new tissues and organs that can restore or enhance the function of natural ones.
Conclusion
PLGA-based scaffolds are advancing tissue engineering by providing suitable platforms for cell growth and tissue regeneration. PLGA is a biodegradable and biocompatible polymer that can be fabricated, characterized, modified and combined to create scaffolds for different tissues and organs. PLGA-based scaffolds can have many benefits for patients, researchers and developers, such as improved health, increased knowledge and reduced costs.
However, using PLGA-based scaffolds also poses some challenges, such as technical difficulties, biological uncertainties and ethical issues. Using PLGA-based scaffolds requires careful consideration and evaluation of the benefits and challenges of each tissue engineering application. Using PLGA-based scaffolds also requires collaboration and communication among the stakeholders involved in or affected by tissue engineering.