editorial bioactive materials for bone tissue...

EditorialBioactive Materials for Bone Tissue Engineering

Julietta V. Rau,1 Iulian Antoniac,2 Giuseppe Cama,3

Vladimir S. Komlev,4 and Antonio Ravaglioli1

1 Istituto di Struttura della Materia-Consiglio Nazionale delle Ricerche (CNR-ISM), Via del Fosso del Cavaliere,100-00133 Rome, Italy2Biomaterials Group, Materials Science and Engineering Faculty, University Politehnica of Bucharest,Splaiul Independentei 313, Building J, Room JK109, Sector 6, 060032 Bucharest, Romania3Polymer Chemistry & Biomaterials Group, Krijgslaan 281 (S4-Bis), 9000 Ghent, Belgium4A. A. Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Leninsky Prospect 49,Moscow 119991, Russia

Correspondence should be addressed to Julietta V. Rau; [email protected]

Received 12 January 2016; Accepted 13 January 2016

Copyright © 2016 Julietta V. Rau et al. This is an open access article distributed under the Creative Commons Attribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

For early biomaterials, it was required to have a combinationof physicochemical properties, suitable to replace humanbody tissues and to be biologically inert. Since then a longway has been brought to the third generation of biomaterials,whose role is to be both resorbable and bioactive, that is, to beable to elicit a controlled action in physiological conditions.Recently, the advances in cellular proteomics and genomicspaved the way to the fourth generation of biomaterials,known as biomimetic and smart materials, and to theirapplication in regenerative medicine.

There is a wide range of materials used for orthopaedicsand dentistry, from metals, alloys, ceramics, and polymersto bioactive glass systems and hybrid composites. It is veryimportant to know the performance of these materials usedin clinical practice or of some newly developed materials,starting from in vitro tests to the in vivo animal models.

This issue is focused on the new frontiers in researchstudies dedicated to the use of bioactive materials in differentforms, like scaffolds, composites, or coatings, for biomedicalapplications and related clinical investigations. Based onthe requirements of the modern biomedical technology, thenovel research strategies in biomaterials field are nowadaysdirected towards biomaterials endowed with surface prop-erties and characteristics suitable for drug delivery and forthe controlled release of active principles, especially againstinfections.

In this view, several research groups have been invited tocontribute to this special issuewith their original research andreview papers that could stimulate efforts of comprehensiveknowledge of bioactive materials with clinical applicationsin bone tissue engineering. This special issue is divided intothree categories based on the following keywords: bioactivematerials performance, smart materials and technologies forbone tissue engineering applications, bioactive coatings forosseointegration, and antimicrobial activity.

In the category of bioactive materials performance, cal-cium phosphate and bioactive glass based materials haveattracted a significant attention being widely used in bonetissue engineering. In particular, calcium phosphates aremore traditional for bone graft substitution, since theircomposition is close to the mineral part of the bone tissue.However, their performances could still be improved.

I. Ajaxon et al. evaluated the long-term in vitro degra-dation of high-strength brushite calcium phosphate cementsover a time period of 25 weeks in water, phosphate bufferedsaline, and a serum solution. The compressive strength,chemical composition, and microstructure were also evalu-ated, and important changes in the properties of the cementswere observed after 10 weeks of incubation time.

Y. Ayukawa et al. evaluated the tissue/cellular responsetoward the low-crystalline carbonate apatite (CO

3Ap), the

form of apatite found in bone, which was fabricated using

Hindawi Publishing CorporationBioMed Research InternationalVolume 2016, Article ID 3741428, 3 pageshttp://dx.doi.org/10.1155/2016/3741428

2 BioMed Research International

a dissolution-precipitation reaction with set gypsum as aprecursor. Both CO

3Ap and sintered hydroxyapatite, used as

a control, were implanted into surgically created tibial bonedefects of rats for histological evaluation. Authors observedthat the CO

3Ap granulesmimicked the bonematrix, suggest-

ing that CO3Ap may be an appropriate bone substitute.

B. Sarikaya et al. developed porous collagen/𝛽-tricalciumphosphate (TCP) based scaffolds with superior mechanicalproperties. The scaffolds obtained via dehydrothermal pro-cessing are able to bend and be rolled, making them suitablefor a wide range of handlings. This study suggested that thecross-linked collagen/𝛽-TCP scaffolds show great potentialfor use in bone tissue engineering applications.

W. P. Chan et al. described the technique for synthesizingof biocompatible alginate/poly(𝛾-glutamic acid) base gel withpotential application as injectable bone repair material. Eval-uation of its mechanical properties, swelling behaviour, andblood compatibility showed the nontoxicity of this materialand that it could be used for repairing of bone defects.

Concerning bioactive glasses, the focus point is theirability to continuously exchange ions with physiologicalliquids, releasing appropriate trace elements in order tostimulate specific cellular response, aimed at activating genesresponsible for osteogenesis and bone tissue regeneration.

N. A. P. van Gestel et al. provided an overview on S53P4bioactive glass current clinical results in such applications ascraniofacial reconstructions, grafting of benign bone tumourdefects, instrumental spondylodesis, and the treatment ofosteomyelitis, whereas D. Bernardeschi et al. evaluated thecutaneous and the inner ear tolerance of S53P4 bioactive glasswhen used in the mastoid and epitympanic obliteration forchronic otitis surgery. Bioactive glass granules resulted to bewell tolerated for primary or revision chronic otitis surgery.

In the category of smart materials and technologiesfor bone tissue engineering applications, the advances incellular proteomics and genomics paved the way to the smartmaterials and to their application in regenerative medicine.

F. Wang et al. investigated the osteogenic capacityof nano-hydroxyapatite/chitosan/poly(lactide-co-glycolide)(nHA/CS/PLGA) scaffolds seeded with human umbilicalcord mesenchymal stem cells in the calvarial defects of thenude mice. It was found that nHA and CS enhance the boneregeneration at early stage, opening the way to the scaffoldapplications in bone tissue engineering.

C. Romagnoli et al. analysed the behaviour of a clonalfinite cell line derived from human adipose tissue seeded onpoly(𝜀-caprolactone) film, prepared by solvent casting. Theadipose-derived mesenchymal stem cells (AMSCs) were ableto adhere to the biomaterial and remained viable for the entireexperimental period. Moreover, the proliferation processand osteogenic activity of AMSCs were maintained on thebiofilm, demonstrating that the selected biomaterial ensurescell colonization and the development of an extracellularmineralized matrix.

N.-H. Kim et al. evaluated the effect of rhBMP-2 (recom-binant human bonemorphogenetic protein) applied in differ-ent concentrations to sandblasted and acid etched titaniumimplants, in bone defects of beagle dogs using split-mouthdesign. The authors reported that titanium implants coated

with rhBMP-2 were more effective, compared with untreatedgroup, in promoting bone regeneration and osseointegration.

R. H. Pedersen et al. reported the efficacy of inorganicbone mineral coated with P-15 peptide (ABM/P-15) on tibiadefect repair longitudinally in both normal and osteoporoticrats in vivo. It was shown that the ABM/P-15 accelerated boneregeneration in osteoporotic rats but did not enhance boneregeneration in normal rats.

New advanced technologies could be used to processbioactive materials in order to obtain scaffolds or coatings forbiomedical applications.

D. Du et al. considered the problem of shape matchingbetween bone defects and ceramic scaffolds. Computer-assisted microstereolithography (MSTL) can fabricateanatomically shaped complex three-dimensional structures.However, thermal contraction mismatch between thescaffold material and mold results in shape distortion duringsintering. The authors developed a novel gelcasting indirectMSTL technology to overcome this problem and successfullyfabricated beta-tricalcium phosphate scaffolds for rabbitfemur. The reported fabrication method could be useful forconstructing bone substitutes specifically designed accordingto local anatomical defects.

M. B. Bezuidenhout et al. reviewed the studies related tothe titanium-based hip stemswith drug delivery functionalitythrough additive manufacturing, starting from the idea thatthe treatment of infected femoral stems is a major problemin clinical practice and remains an area of debate. Throughadditive manufacturing, antibiotics can be incorporated intocementless femoral stems to produce prosthetic deviceswith antimicrobial properties. The review highlighted themicroorganisms associated with total hip arthroplasty, dis-cussed the advantages and disadvantages of the latest mate-rials used in hip implants, compared different antimicrobialagents that could be incorporated, and addressed novel ideasfor future research.

In the category of bioactive coatings for osseointegrationand antimicrobial activity, the novel research strategies inbiomaterials field are nowadays directed towards biomaterialsendowed with surface properties and characteristics suitablefor drug delivery and for the controlled release of activeprinciples, especially against infections.

With this regard, C. S. Ciobanu et al. reported the prepa-ration and characterisation of hydroxyapatite doped withsilver/polydimethylsiloxane composite layer and its antimi-crobial effect against Candida albicans biofilm embeddedcells.

S. Yeniyol et al. reported the preparation and investigationof anatase/rutile mixed-phase TiO

2thin films on commer-

cially pure Ti sheets and their photocatalytic activity forpossible antibacterial use around dental implants. The pho-tocatalytic performance against A. actinomycetemcomitanscolonization was testified.

R. A. Garcia et al. evaluated the polymethyl methacrylateand calcium sulfate as carriers for the local delivery of gallium(III) nitrate (Ga(NO

3)3), which were reported to exert a

broad antimicrobial activity against organisms commonlyassociated with orthopaedic related infections. The in vitrofindings suggested that local delivery of Ga(NO

3)3may be

BioMed Research International 3

an effective strategy for the prevention and/or treatment oforthopaedic related infections. The authors concluded thatfuture studies utilizing animal models are needed to fullycharacterize the clinical role for this treatment modality.

Apart from microstructure and composition characteris-tics, a special stress should be given to the host tissue/materialinterface proven by the in vivo performance.

H.-K. Tsou et al. reported highly osteoblast compati-ble titanium dioxide (TiO

2) coatings on polyetheretherke-

tone (PEEK). After TiO2/PEEK prolonged implantation in

rabbits, histological observation showed newly regeneratedbone formed more prominently. The shear strength of thebone/implant interface increasedwith the increase of implan-tation period. Bone bonding performance of the TiO

2/PEEK

implant was superior to that of the bare PEEK. The rutile-TiO2coatings achieved better osseointegration than the

anatase-TiO2coatings.

By collecting these papers, we hope to enrich our readersand researchers in the field of bioactive materials for bonetissue engineering. We believe that novel bioactive materialswill be an important part of future bone tissue engineeringproducts.

Acknowledgments

We thank all the authors participating in the present specialissue.

Julietta V. RauIulian AntoniacGiuseppe Cama

Vladimir S. KomlevAntonio Ravaglioli

Submit your manuscripts athttp://www.hindawi.com

ScientificaHindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation http://www.hindawi.com Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation http://www.hindawi.com Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttp://www.hindawi.com Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials

editorial bioactive materials for bone tissue...

Documents