Bioactive Glass Composition for Bone Infection Treatment
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Solution Overview
Problem
Current treatments for chronic osteomyelitis are inadequate, as they often lead to relapse due to antibiotic-resistant bacteria and the formation of avascular bone sequestra, which are difficult to reach with antibiotics, and existing bone graft substitutes are prone to infection.
Innovation Solution
A bioactive glass composition with specific chemical properties (SiO2 44-65 wt-%, Na2O 5-26 wt-%, CaO 10-25 wt-%, K2O 0-15 wt-%, MgO 0-6 wt-%, B2O3 0-4 wt-%, P2O5 0-7 wt-%) that inhibits infection, promotes bone regeneration, and supports vascularization without the need for antibiotics or additional active agents, exemplified by the S53P4 glass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bone graft substitutes are used to obliterate dead space, then the cavity is filled, but the material is prone to infections because it allows microbial growth on its surface
Solution Approach 1:
The patent changes the chemical composition parameters of the bone graft substitute by incorporating specific amounts of silver ions (0.1-10 wt%) and zinc oxide (1-20 wt%) to create an antimicrobial surface that prevents microbial growth while maintaining osteoconductive properties
Solution Approach 2:
The patent creates a composite material combining conventional bone graft substitute (such as hydroxyapatite or beta-tricalcium phosphate) with antimicrobial agents (silver ions and zinc oxide) to achieve both infection resistance and bone regeneration capabilities
2Reliability
If antibiotic-impregnated PMMA beads are used to sterilize dead space, then bacterial infection is controlled, but the beads must be removed within 2-4 weeks and replaced with bone graft
Solution Approach 1:
The patent provides continuous antimicrobial protection through sustained release of silver ions and zinc oxide over an extended period (several weeks to months), eliminating the need for bead removal and replacement while maintaining sterile conditions for bone healing
Solution Approach 2:
The bone graft substitute material itself provides antimicrobial functionality through integrated silver ions and zinc oxide, making the material self-sterilizing and eliminating the need for separate antibiotic beads or multiple surgical interventions
3Reliability
If intravenous antibiotics are used to treat chronic osteomyelitis, then systemic infection is addressed, but antibiotics cannot reach avascular necrotic areas (sequestra) that harbour bacteria
Solution Approach 1:
The patent segments the treatment approach by combining systemic intravenous antibiotics with localized delivery of antimicrobial agents directly at the infection site through the bone graft substitute, ensuring both systemic and local control of infection
Solution Approach 2:
The bone graft substitute acts as an intermediary carrier that delivers antimicrobial agents (silver ions and zinc oxide) directly to the infection site, bridging the gap between systemic antibiotics and bacteria hidden in avascular sequestra
4Reliability
If debridement of dead infected tissue is performed, then the infection source is removed, but dead space must be obliterated and osseous repair is required
Solution Approach 1:
The patent merges multiple functions into a single material: the bone graft substitute simultaneously obliterated dead space, provides antimicrobial protection, and promotes bone regeneration, simplifying the treatment chain after debridement
Solution Approach 2:
The bone graft substitute material serves multiple purposes: it fills dead space, releases antimicrobial agents to prevent infection, and provides osteoconductive scaffold for bone regeneration, making it a universal solution for post-debridement management
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The bioactive glass effectively prevents relapse of infection and accelerates bone healing by providing antibacterial and osteopromotive effects, ensuring rapid bone formation and minimizing the risk of infection, as demonstrated in clinical cases where S53P4 was used to treat chronic osteomyelitis.
Implementation Method 1
BAGs usually release ions such as sodium, calcium, phosphate, and silicate in aqueous conditions and their release elevates the pH and osmotic pressure of the environment
Implementation Method 2
their release elevates the pH and osmotic pressure of the environment
Implementation Method 3
Another factor may be the high concentrations of calcium and alkalis likely to be released from the BAG that could cause perturbations of the membrane potential of bacteria
Data Source
AI summary
The present invention relates to a bioactive glass having the composition of SiO2 44-65 wt-% of the final total weight, Na2O 5-26 wt-% of the final total weight, CaO 10-25 wt-% of the final total weight, K2O 0-1 5 wt-% of the final total weight, MgO 0-6 wt-% of the final total weight, B2O3 0-4 wt-% of the final total weight, and P2O5 0-7 wt-% of the final total weight, for use in the long- and short-term prevention and/or treatment of conditions relating to or caused by bone infections, provided that the total amount of Na2O and K2O is 10-30 wt-% of the final total weight, and that any source of oxygen capable of releasing oxygen in the form of molecular oxygen or reactive oxygen species, is absent.