Scanning electron microscopic study of cell attachment to biodegradable polymer implants.

Area of Science:

• Biomaterials Science
• Tissue Engineering
• Polymer Chemistry

Background:

• Biodegradable polymers, specifically polylactic acid (PLA) and polyglycolic acid (PGA), are investigated as carriers for bone regeneration compounds.
• Incorporating osteo-inductive substances into poly-(DL, lactide-co-glycolide) copolymer implants can improve bone defect repair.

Purpose of the Study:

• To investigate the attachment of cells and tissue matrix to biodegradable polymer implants using Scanning Electron Microscopy (SEM).
• To evaluate the influence of hydroxyapatite (HA) and autolyzed, antigen-extracted (AA) bone particles on polymer-cell interactions.

Main Methods:

• Three groups of 50:50 PLA-PGA copolymer implants were prepared: plain, with HA, and with AA bone particles.
• Implants were surgically placed into rat pectoralis muscles.
• Samples were collected at 7, 14, and 21 days post-implantation for SEM analysis.

Main Results:

• Early stages (7 days) showed blood cells and fibrinoid clot formation on implants.
• Polymer degradation was observed through enlarging pores and changes in surface morphology (lobular, fibrinoid).
• Later stages (14-21 days) revealed replacement of inflammatory cells by fibroblasts and collagen, with exposed HA/AA particles showing limited cell adhesion.

Conclusions:

• Biodegradable polymer degradation progresses over time, altering the implant surface.
• Cellular adhesion patterns shift from initial inflammatory responses to fibroblast and collagen deposition.
• Degradation appears to be a primary factor influencing cell attachment, potentially overriding the effect of embedded HA or AA particles.