Lecture 2 Flashcards
There is a great need/interest
to assess the performance/quality of a biomaterial.
- To ensure patients safety
- To improve treatments and follow-up
- To define industrial standards
- To define regulations
- To evaluate new products and discoveries
What is biocompatibility?
Ability of a material to perform with an appropriate host response in a specific application.
Is biocompatibility an intrinsic property?
No, depends on the context of use. (Ex: use of teflon as vein catheter is OK, but not as artificial ACL
Local Interactions of Biomaterials, Material -> Host
- Toxicity
- Inflammation / Fibrosis
- Modification of healing
- Blood-material interact. (thrombosis)
- Infection
- Tumorgenesis
- Activation of cell. activity
Local Interactions of Biomaterials, Host -> Material
- Hydration/dissolution
- Corrosion/degradation
- Resorption
- Wear, cracking, fatigue
- Fibrous encapsulation
- Calcification
Systemic internactions with biomaterial
- Lymphatic , blood transport
- Accumulation in fat, liver…
- Blood-material interact. (embolization)
- Hypersensitivity
- Nervous stimulation
- Drug release
The main types of biomaterials-related reactions:
- Blood-material interactions (inevitable)
- Inflammatory reactions (inevitable)
- Remote and systemic effects (can be good or bad)
- Infectious reactions (bad)
- Tumor formation (bad)
Does fibrosis go away after implantation?
No. FBR is persistent and remains for the entire duration of the implantation. Loss of mechnical behavior (stiffening).
Ex: Breast implant -> loss of shape. Pacemaker -> lose electrical contact. Hip implant -> weak mechanical anchor.
Traditional “biocompatible” materials
show a low level, long term minimal FBR*
- mild inflammatory response - thin fibrous capsule after 2-3 weeks
- quiescent local inflammatory reaction
- no adverse local or systemic response
Important factors impacting biocompatibility
- Toxicity of leachable or degradation products - Reactions to products of extrinsic microbiologic organisms
- Mechanical effects (stiffness, size, shape, μmotion)
- Cell-material and Protein-material interactions
Innovations that have better interfaces with biological tissues
Implant biointegration through porosity control, Implants from decellularized tissues, Peptide-grafted surface to guide tissue integration
Bioactivity
Bioactivity is the ability to induce (beneficial) effects on cells, usually by triggering or favoring specific cellular mechanisms.
Bioactivity : the case of bone reconstruction
Hydroxyapatite, Calcium phosphates and bioglasses. Initiate osteoconduction/induction
Mechanisms for osteoconduction/induction
- Dissolution
- Precipitation
- Ion exchange and structural rearrangement
- Interdiffusion
BIOACTIVE EFFECTS - Solution mediated effects on cellular activity
6-7. Deposition of compounds with or without
integration in the ceramics - Chemotaxis
- Cell attachment and proliferation
- Cell differentiation
- ECM formation
Osteoconduction
Ability of an implant or scaffold to promote the attachment of osteoblastic cells on the surface or inside the implant/scaffold. (Ex: osteoconductive coating on implant, biodegradable scaffolds)
