Strong bioresorbable Ca phosphate-PLA nanocomposites with uniform phase distribution by attrition milling and high pressure consolidation

Rakovsky, A.; Готман, И.; Rabkin, Eugen; Gutmanas, E.Y.

doi:10.1016/j.jmbbm.2012.11.004

Cited by 26 publications

(17 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The use of high‐heat and solvents, however, results in denaturation of the biomolecules, as well as aggregation and phase separation of additives during blending, compromising both efficacy and consistency of results. Current research focuses on combining the use of reduced solvents with low‐temperature mixing, but typically involves a compromise between maximum loading ability and homogeneity of dispersion. Apart from the concerns over the use of potentially toxic solvents and its residuals, homogeneity of dispersion is essential to attain high mechanical performances from composite materials, as highlighted by Coroller et al recently …”

Section: Introductionmentioning

confidence: 99%

Polymer Powder Processing of Cryomilled Polycaprolactone for Solvent‐Free Generation of Homogeneous Bioactive Tissue Engineering Scaffolds

Lim

Chong

Chan

et al. 2014

Small

View full text Add to dashboard Cite

Synthetic polymers used in tissue engineering require functionalization with bioactive molecules to elicit specific physiological reactions. These additives must be homogeneously dispersed in order to achieve enhanced composite mechanical performance and uniform cellular response. This work demonstrates the use of a solvent-free powder processing technique to form osteoinductive scaffolds from cryomilled polycaprolactone (PCL) and tricalcium phosphate (TCP). Cryomilling is performed to achieve micrometer-sized distribution of PCL and reduce melt viscosity, thus improving TCP distribution and improving structural integrity. A breakthrough is achieved in the successful fabrication of 70 weight percentage of TCP into a continuous film structure. Following compaction and melting, PCL/TCP composite scaffolds are found to display uniform distribution of TCP throughout the PCL matrix regardless of composition. Homogeneous spatial distribution is also achieved in fabricated 3D scaffolds. When seeded onto powder-processed PCL/TCP films, mesenchymal stem cells are found to undergo robust and uniform osteogenic differentiation, indicating the potential application of this approach to biofunctionalize scaffolds for tissue engineering applications.

show abstract

Section: Introductionmentioning

confidence: 99%

Polymer Powder Processing of Cryomilled Polycaprolactone for Solvent‐Free Generation of Homogeneous Bioactive Tissue Engineering Scaffolds

Lim

Chong

Chan

et al. 2014

Small

View full text Add to dashboard Cite

show abstract

“…There are several variations of SPD based techniques such as high pressure torsion (HPT) [53][54][55], equal channel angular pressing (ECAP)/equal channel angular extrusion (ECAE) [56][57][58][59][60], cold rolling [61][62][63][64][65], hot rolling [66][67][68], high energy milling (ball milling) [69][70][71][72][73], sandblasting [74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89][90], and shot peening [91][92][93].…”

Section: Fabrication Of Nanocrystalline Metalsmentioning

confidence: 99%

Green Techniques for Biomedical Metallic Materials with Nanotechnology

Guo

Tam

2015

Green Processes for Nanotechnology

View full text Add to dashboard Cite

From a clinic or medical viewpoint, it is important that the surgical implant retains a combination of high strength (including surface wear resistance), good biocompatibility, and chemical stability. To enable safe interactions between the surgical implants and tissues, surface modification and functionalization are commonly employed.Biological coatings such as TiN and titanium oxides are widely adopted and functionalized with various biological properties such as corrosion resistance, bioactivity, cytocompatibility, and bioconductivity. However, failure of the biological coatings due to the long term corrosion and wear or fretting is the main problem and debris from the materials is the main cause of joint replacement failure. Since the surgical implants are implanted into the human body for a long time, cyclic motions between the surgical implants and human tissues may disrupt the protective biological coatings accelerating corrosion and increasing the risks of immunological response by the leached metallic ions.Therefore, improved metallic biomaterials and the relevant manufacturing techniques are being introduced to meet this demand. Apart from the biocompatibility requirement, metallic biomedical materials also have to meet high standards regarding its performance (functionality, reliability) and selection criteria (cost, manufacturing ability). Up to now, the most often used metallic biomedical materials include stainless steel, cobalt-based alloys, and commercially pure titanium or titaniumbased alloys. However, the implant metallic biomaterials, like all mechanical components, are subjected to degradation and have limited lifetime. Damaged implant requires successive operation to replace worn components and so intensive efforts are made to increase durability of implants metallic biomaterials.For enhancing the mechanical retention, engineered nanostructures on the surface are normally taken to increase effective surface area on implant surfaces (such as both dental and orthopedic applications) to exhibit biological, mechanical, and morphological compatibilities to receiving vital hard/soft tissue, resulting in promoting osseointegration.

show abstract

“…Rakovsky et al generated PLA-TCP composites with uniform distribution through attrition milling 221 and demonstrated the mechanical advantages of doing so. On the other hand, Paik et al electrospun PCL-TCP nanofibers 222 and showed that MC3T3-E1 osteoblasts proliferated and differentiated well on these bioactive composite matrices.…”

Section: Tricalcium Phosphatesmentioning

confidence: 99%

“…In addition, recent interests in developing drug-incorporated polymer composites have also been limited to nonthermosensitive drugs, due to the presence of elevated temperature during processing. As such, low-temperature processing methods have been explored for the development of bioactive composites125,221 .…”

mentioning

confidence: 99%

“…Bleach et al 217 incorporated up to 25 vol% of CaP into polylactide (PLA), and showed the amount of CaP was inversely correlated to tensile strength. In a unique study, Makarov et al 129 managed to fabricate polycaprolactone (PCL)based CaP composites with unusually high volume fractions (80-95 vol%) through in situ CaP formation.Apart from demonstrating the dependence of moduli on varying volume fractions of CaP221 , Rakovsky et al also showed that these composites were able to maintain their mechanical properties under mild degradation conditions over one month. On this note, Teoh's group has also made significant contributions to the degradation stability of PCL/CaP composites, although it was limited to tricalcium phosphate (TCP) loading of 20 wt% 180.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Parametric studies of polycaprolactone-based composites for tissue engineering and regenerative medicine

Lim¹

View full text Add to dashboard Cite

Bone is a composite structure that is made up of collagen (organic), calcium phosphates and trace metal elements (inorganic). Together with strict mechanical requirements, many scaffold-based tissue engineering strategies are now focused on developing composite systems that provide sufficient mechanical stability and biological stimulation to dictate osteogenic events in vivo. On this note, processing techniques for bioresorbable composites for bone tissue engineering have traditionally involved solvents and heat, which may not be ideal due to toxicity and material degradation, respectively. As such, alternative processing methods are actively pursued and evaluated. In this thesis, we hypothesized that cryomilling is a potential alternative processing technique for composites. The effectiveness of cyromilling to refine particle size was first demonstrated using PCL and PLGA. Strength improvement was demonstrated, particularly in the case of PLGA. By subjecting composite materials to temperatures sufficiently below glass transition, effective attrition into fine powders (micron-range) was achieved. In addition, this attrition process facilitated distribution of the fillers (tricalcium phosphate (TCP) and magnesium (Mg)), resulting in homogeneous PCL/TCP and PCL/Mg powders. This homogeneous distribution was retained in further postprocessing techniques. A mechanistic explanation for this phenomenon may be that of solid-state diffusion, where effective interfacial interactions are created, resulting in the retention of their homogeneous distributions. The implications of this phenomenon were demonstrated through a variety of in vitro studies, with notable advantages in composites processed with cryomilling (such as mechanical and biological responses). In vivo, PCL/TCP films were able to influence I would like to thank my supervisors Prof. Teoh Swee-Hin and Dr. Mark Chong for their supervision and guidance during the course of my study. Prof. Teoh has been instrumental in guiding my vision and maintaining my hunger and passion for research. He has been an inspiration to me ever since our association in my third year of undergraduate studies, through my FYP, Masters, and culminating in my PhD. I will never forget this phrase "Your mind must be like a parachute; It works best when open", one which is famous, and has guided the minds of many under him. Dr. Mark, whom I have known since my undergraduate days, has been simply one of the most dedicated and meticulous researchers I have met. He has undying passion for research, constantly seeking the scientific question. Through my time with him, I have matured much, and am looking forward to more exciting times ahead.

show abstract

Strong bioresorbable Ca phosphate-PLA nanocomposites with uniform phase distribution by attrition milling and high pressure consolidation

Cited by 26 publications

References 32 publications

Polymer Powder Processing of Cryomilled Polycaprolactone for Solvent‐Free Generation of Homogeneous Bioactive Tissue Engineering Scaffolds

Polymer Powder Processing of Cryomilled Polycaprolactone for Solvent‐Free Generation of Homogeneous Bioactive Tissue Engineering Scaffolds

Green Techniques for Biomedical Metallic Materials with Nanotechnology

Parametric studies of polycaprolactone-based composites for tissue engineering and regenerative medicine

Contact Info

Product

Resources

About