Introduccion a los biomateriales

Acute inflammation on ePTFE vascular graft

Biomaterials: Applications
BME 416/516 9-04-2007 04F C F F C F n

leukocytes fibrin cap

leukocytes

ePTFE vascular graft

Fibrous capsuleformation on silicone breast prosthesis
breast prosthesis leaked silicone gel fibrous capsule

Morphological: review
• Protein adsorption • Infection
– More topographical features (grooves, pores,machine marks) expose more surface area, leading to more protein adsorption – Roughness often leads to the dead space with no tissue ingrowth; This is a perfect shelter ingrowth; for the bacterialcolonies, occasionally leading to serious infection

fibrous capsule

macrophages and a few giant cells phagocytosing (foamy) silicone gels

Morphological: review
• Foreign body reaction
– Moremacrophages and foreign body giant cells are found around textured material surfaces than on smooth surfaces

Porous coatings
• • • •
Encourage tissue ingrowth Mechanical interlocking Increasesfixation of implants Orthopedic implants
– Hip and knee replacements – Need to be anchored to the heart muscle – Where they penetrate the skin

• Fibrous capsule formation
– Smooth surfaces induce athicker fibrous capsule than rough or textured surfaces

• The cuffs of heart valves

• The regions of percutaneous implants

1

Physicochemical: review
Protein-resistant coatings:Proteinhydrophilic but low surface free energy

Plasma treatment
• Surfaces are exposed to ionized inert gas (a • Increases surface free energy of many metals • •
and polymers; typically makes the surfacehydrophilic Increases tissue adhesion Energetic species in the plasma can break bonds; the polymers can be cross-linked → crosssurface permeability↓, hardness↑ permeability↓ hardness↑ plasma), a.k.a.glow discharge

Ethylene glycol; HOCH2CH2OH

PEG: HO-(CH2-CH2-O)n-H HO-

Calcium phosphate coatings
• Calcium phosphate ceramic coatings on
metallic implants
– Because of their chemical...