Handheld 3D Printer for Bone Defect Repair
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Solution Overview
Problem
Current bone grafting methods for treating large bone defects are invasive, costly, and often require secondary surgeries, with existing bone grafts lacking precision and ability to integrate effectively with live cells, leading to incomplete tissue regeneration and potential infections.
Innovation Solution
A handheld 3D printer is used to apply a composite filament made of polycaprolactone (PCL) doped with zinc oxide nanoparticles and hydroxyapatite microparticles, allowing for in situ printing of scaffolds that adhere to bone defects, eliminating the need for drilling or screws, and enabling faster nutrient access and bone restoration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bone grafting methods are used, then bone defects can be treated, but the procedures are invasive, costly, and require secondary surgeries
Solution Approach 1:
The patent changes the physical state of the polymer material from solid to melt flowable state by controlling temperature, enabling the material to be applied in a liquid form that can fill bone defects and then solidifies upon cooling. This eliminates the need for complex drilling and screw fixation procedures while maintaining effective bone regeneration
Solution Approach 2:
The patent replaces mechanical fixation systems (drills, screws, plates) with a thermal-based application system. The polymer is heated to become flowable, applied to the bone defect, and then solidifies to provide fixation and support, substituting mechanical fastening with thermal processing and material phase change
2Strength
If permanent plates and screws are used for bone fixation, then bone fractures can be stabilized, but reoperation is needed for implant removal
Solution Approach 1:
The patent uses biodegradable polymeric materials that gradually degrade and are absorbed by the body over time. The material provides necessary mechanical support during bone healing and then naturally disappears, eliminating the need for removal surgery. The degradation products are non-toxic and can be metabolized by the body
Solution Approach 2:
The patent employs materials with time-dependent property changes - the polymer starts with high mechanical strength for fixation, then gradually degrades as bone heals, transitioning from a permanent implant to a temporary support structure that naturally disappears
3Manufacturing precision
If traditional bone grafts are used, then bone voids can be filled, but precision and integration with live cells are insufficient
Solution Approach 1:
The patent incorporates different functional components within the polymer material - osteoinductive factors, osteoconductive surfaces, and growth factors - at specific locations and concentrations to promote localized bone regeneration and enhance integration with surrounding live tissue
Solution Approach 2:
The patent uses composite polymeric materials combining biodegradable polymers with bioactive components such as hydroxyapatite, growth factors, and osteoinductive agents. This composite structure provides both mechanical support and biological functionality for enhanced tissue integration
4Strength
If surgical plates and screws are used, then bone fixation is achieved, but patient discomfort and surgical time increase
Solution Approach 1:
The patent extracts and eliminates the time-consuming steps of drilling holes, inserting screws, and tightening plates from the surgical procedure. The material is simply applied to the bone defect in melt form and solidifies immediately, reducing surgical time while maintaining fixation strength
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 solution provides a quick, less invasive, and cost-effective method for bone regeneration, with the printed scaffolds showing moderate adhesion to bone tissue, supporting osteodifferentiation of mesenchymal stem cells, and reducing the risk of scaffold dislocation and bacterial infection.
Implementation Method 1
A handheld 3D printer is used to apply a composite filament made of polycaprolactone (PCL) doped with zinc oxide nanoparticles and hydroxyapatite microparticles
Implementation Method 2
The subject invention can replace fracture fixation devices in no-load bearing applications such as CMF and can be used for load bearing applications in conjunction with fracture fixation devices. The material will be heat flowable, absorbable, biodegradable materials
Implementation Method 3
The printed scaffolds showing moderate adhesion to bone tissue, supporting osteodifferentiation of mesenchymal stem cells, and reducing the risk of scaffold dislocation and bacterial infection
Implementation Method 4
supporting osteodifferentiation of mesenchymal stem cells
Implementation Method 5
allowing for in situ printing of scaffolds that adhere to bone defects, eliminating the need for drilling or screws
Implementation Method 6
The material will be heat flowable, absorbable, biodegradable materials with no drilling or screw type hardware for bone flap fixation of craniotomy
Data Source
AI summary
A filament or printing material placed in a syringe for 3D printing comprising polymers, proteins, and/or functional particles and materials is provided. Methods of treating a bone defect in a subject in need thereof comprising using a handheld 3D printer to apply a filament or the printing material placed in a syringe to the bone defect of the subject are also provided. Methods of fixing or gluing natural or synthetic bone grafts using a handheld 3D printer to apply a filament or the printing material placed in a syringe over and around the defect or at the interface of a flap and the bone. Methods of printing a graft cage for retaining bone grafts and/or bone graft substitute in its desired location during healing for treatment of critical-sized segmental defects in long bones are provided.