Biomaterials and Biomimicry Quiz

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Questions and Answers

Based on the information provided, which of the following is NOT a reason why synthetic biomaterials often fail to match the form and function of the human body?

Synthetic biomaterials often struggle to mimic the spatial organization and intricate structures present in biological tissues.

Synthetic biomaterials lack the chemical complexity and diversity found in natural biological structures.

Synthetic biomaterials can exhibit different mechanical properties and fail to match the dynamic nature of living tissues.

Synthetic biomaterials are typically designed to be biocompatible, meaning they do not elicit an immune response within the body. (correct)

The term "biomimicry" in the context of this text refers to:

The development of materials that closely mimic the biological form and function of natural structures. (correct)

The use of biomaterials to enhance the performance of synthetic materials.

The process of replacing biological materials with synthetic alternatives.

The study of living organisms to understand their complex structures and functions.

Which of the following is NOT a class of biomaterials mentioned in the provided content?

Alloys (correct)

Metals

Ceramics

Composites

Based on the information provided, which of the following is an example of a biomaterial used in bone tissue engineering?

All of the above Signup and view all the answers

The example of gecko-feet inspired materials highlights which key principle of biomimicry?

Adopting structural features of natural organisms to achieve specific functions. Signup and view all the answers

What is one approach to counteract the degradation of fibrin gels caused by plasmin?

Use tranexamic acid Signup and view all the answers

Which of the following is a significant challenge associated with fibrin as a biomaterial?

Inconsistent degradation rates Signup and view all the answers

What mechanical property is expected when using fibrinogen concentrations of 30 mg/mL?

High chemical stability but impaired cell spreading Signup and view all the answers

What common agents are produced by various cells that can counteract the efficacy of fibrin gels?

Plasmin and matrix metalloproteinases (MMPs) Signup and view all the answers

What is a consequence of combining fibrin with other synthetic or natural polymers?

Altered cell response Signup and view all the answers

Which characteristics are true for glycosaminoglycans (GAGs)?

They resist compressive forces and are highly permeable. Signup and view all the answers

What is the primary function of fibrous proteins in the extracellular matrix (ECM)?

To provide structural and adhesive support. Signup and view all the answers

What main difference exists between glycoproteins and proteoglycans?

Glycoproteins have protein components that significantly outweigh carbohydrate components. Signup and view all the answers

Which method is NOT typically used for sourcing extracellular matrix (ECM) proteins?

Synthesis using stem cell differentiation. Signup and view all the answers

What type of charge is typically associated with proteoglycans?

Negatively charged. Signup and view all the answers

Study Notes

Course Information

Course Title: Biocompatible Materials
Course Code: 376-1714-00L
Topic: Materials of biological origin I
Date: 16.10.2024
Instructors: Dr. Markus Rottmar, Prof. Dr. Katharina Maniura, Prof. Dr. Marcy Zenobi-Wong

Biomaterials - Classification

Biomaterials are categorized into classes, including metals, ceramics, synthetic polymers, natural macromolecules, and composites.
Natural macromolecules represent a subclass of biomaterials derived from biological sources.

Evolution of Biomaterials

Biomaterials have evolved through generations, progressing from non-bioactive and non-bioresorbable, to bioactive and/or bioresorbable, to both bioactive and bioresorbable, and lastly biomimetic cell-responsive materials.
First, second, third, and fourth generations are defined by the scale of biomaterial use
This has shifted from a microscale to a nanoscale approach, increasingly sophisticated bio-inspired solutions.

Motivation for Biomimicry

Synthetic biomaterials often lack the precise form and function of natural tissues, including the chemical, spatial, and temporal characteristics.
Biomimicry strives to understand how natural structures produce specific functions, replicating form to enable similar function in artificial contexts.
Gecko feet, for example, are studied to achieve efficient dry adhesives.

Biomimetic Biomaterials - Bone Tissue Engineering (TE)

Biomimetic materials serve as scaffolds for tissue regeneration, often inspired by the structure and function of biological tissues.
Bone TE involves, for instance, the creation of scaffolds with optimized biochemistry and topography to stimulate bone regeneration.

Biomimicry - Range of Characteristics

Native ECM properties are necessary to reproduce for effective biomaterials. Properties to consider include:
- Mechanical properties
- Enzyme remodeling
- Growth factor interactions
- Biocompatibility
- Non-immunogenic

Biological Materials for Tissue Engineering

Biological materials are often advantageous because cells are pre-integrated, factors for correct placement are already present from nature, and specific enzymes are already within the system
These enable the creation of biomaterials that function at the molecular, rather than the macromolecular, level.

Materials of Biological Origin

Low toxicity and minimal foreign body reaction are desired characteristics.
Degradation through naturally occurring enzymes is a consideration in implant design.
Immunogenicity, isolation, and processing are often significant challenges with biopolymers.
Examples of relevant biopolymers include chitosan, silk fibroin, hyaluronic acid, and collagen.
Natural materials exhibit a mix of biological properties. Some are highy immunogenic while some are low immunogenic.

Fibrin overview & Properties

Fibrin is a key component of blood clotting, vital for homeostasis.
It provides a provisional matrix for tissue repair, facilitating cell adhesion, migration, and proliferation
Fibrin's structural and mechanical properties are relevant to its use in tissue engineering applications.
Fibrin's properties can be modified and manipulated.
Porosity and overall clot structure can be controlled to tune its mechanical properties, such as stiffness.
Concentration also influences structural characteristics.

Fibrin Polymerization

Thrombin cleaves fibrinogen to form fibrin.
Fibrin monomers self-assemble in a staggered, overlapping arrangement to create protofibrils.
Factor XIIIa crosslinks the protofibrils into fibrin fibres.

Fibrin as Tissue Scaffold/Biomaterial

There is a historical perspective of the use of fibrin in various applications, from initial use in hemostasis to more recent use as a tissue adhesive and sealant.
It demonstrates a complex but potential application in tissue engineering and regenerative medicine
There are also notable challenges in its application in tissue engineering.

Fibrin as Delivery Vehicle

Fibrin clots can be used to deliver medicinal substances or growth factors.
By controlling the clot's composition, you can also tune the release rate of the therapeutic molecule.

Clinical Practice: Fibrin Glue

Fibrin glue is clinically approved for hemostasis and as an adhesive.
It's applied via double syringes containing fibrinogen and thrombin solutions.
The composition differs between manufacturers.

Fibrin Challenges

Lifespan, mechanical properties and compatibility with other polymers/materials are significant challenges when using fibrin as a biomaterial.

Two-Barrel Syringe Applicator

A specific method for accurately delivering fibrinogen and thrombin, essential for precise control.
This two-layered delivery helps to create homogeneous scaffolds (or tissues).

Decellularization

A biological process to remove cellular components from tissues or organs while preserving the extracellular matrix (ECM).
Key elements removed are:
- Nuclear material
- Lipids
- Proteins.

Advantages and Disadvantages of Tissue Decellularization:

Advantages: Minimize immunogenicity and keep the architecture in the tissue.
Disadvantages: Sometimes incomplete removal of cells

Decellularized Tissue-Derived Biomaterials:

Decellularization processes are used to generate biomaterials from various tissues and organs.
Corneal (eye) ECM is an example where decellularization has provided useful results for generating tissue-engineered hydrogels

Examples for de-cellularized tissue products:

Small intestinal submucosa (SIS) are now used as scaffolds in various bioengineering applications

Decellularization of Tissues and Organs

A process to effectively generate decellularized tissue or whole organ scaffolds.

Whole Organ Decellularization

Different methods, such as retrograde perfusion, are used to eliminate cells within an organ.
This facilitates the creation of "ghost tissue" scaffolds for tissue engineering.

ECM (Extracellular Matrix)

The ECM is the extracellular substance that surrounds cells in tissues and organs.
It's a complex mixture of proteins and carbohydrates.
A key scaffold for tissue engineering applications.

ECM and its different components.

The major components of the ECM include GAGs (glycosaminoglycans), fibrous proteins, and integrated molecules (e.g., growth factors).
These components play various structural and functional roles in tissues.
ECM structure directly influences development, differentiation, and overall tissue function.

Hyaluronic Acid (HA)

A glycosaminoglycan present in high concentrations in many connective tissues.
HA shows excellent biocompatibility.
HA exhibits advantageous viscoelastic properties.
Modification of HA is feasible to tailor desired properties.

HA-based Biomaterials

HA is widely used for diverse applications like brain and neuronal regeneration and cardiovascular tissue engineering.

Proteoglycans

Proteoglycans are critical components of the extracellular matrix.
They support and regulate ECM structure and functions.
Various applications exist in various contexts within bone tissues and in tissue engineering.
Proteoglycans are coated onto or physically incorporated into biomaterial scaffolds to improve properties and functions, to be implemented and regulate tissue regeneration

Collagen-Based Biomaterials:

Collagen is the most abundant protein in the body and a primary component of ECM.
Used to create biocompatible scaffolds for tissue engineering and various applications.
Collagen's properties can be manipulated.

Bone-Collagen-Hydroxyapatite Scaffolds

These scaffolds exhibit enhanced stability and drug release characteristics, improving bone formation in tissue engineering applications.

Fibronectin

A crucial multidomain glycoprotein found in all vertebrates.
Critical for essential functions like cell attachment, migration, and interactions within the ECM.

Laminin

It's a glycoprotein playing an essential role in cell attachment, migration, and regulation of cell growth and differentiation.
Laminin possesses several domains involved in binding crucial ECM components.

Using Whole ECM Instead of Individual Proteins in TE

Utilizing the entire extracellular matrix (ECM) alongside individual ECM protein components in tissue engineering (TE) can safeguard tissue-specific features.

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Description

Test your knowledge on synthetic biomaterials, their applications, and the principles of biomimicry. This quiz covers challenges, examples, and properties associated with biomaterials used in tissue engineering, focusing on their compatibility with human body functions. Dive in to explore the fascinating intersection of biology and engineering!