Revista de Ciencias Tecnológicas (RECIT). Volumen 3 (1): 10-22.
Revista de Ciencias Tecnológicas (RECIT). Universidad Autónoma de Baja California ISSN 2594-1925
Volumen 3 (4): 213-221. Octubre-Diciembre 2020 https://doi.org/10.37636/recit.v34213221.
213
ISSN: 2594-1925
Temperature effect on the porosity of hydroxyapatite
scaffolds and its use in tissue engineering
Efecto de la temperatura sobre la porosidad de andamios de hidroxiapatita y
su uso en ingeniería de tejidos
Vareska Lucero Zarate-Córdova
1
, Mercedes Teresita Oropeza-Guzmán
2
, Eduardo Alberto López-Maldonado
3
, Ana Leticia Iglesias
1
, Theodore Ng
4
, Eduardo Serena-Gómez
5
, Graciela Lizeth Pérez-González
1,3
, Luis Jesús
Villarreal-Gómez
1,3
1
Facultad de Ciencias de la Ingeniería y Tecnología, Universidad Autónoma de Baja California, Tijuana, Baja California,
México.
2
Centro de Graduados, Instituto Tecnológico de Tijuana, Tijuana, Baja California, México.
3
Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Tijuana, Baja California, México.
4
Oakland Oral and Maxillofacial Surgery, Oakland, California, United States.
5
Facultad de Ciencias de la Salud, Universidad Autónoma de Baja California, Tijuana, México.
Corresponding author: Dr. Luis Jesús Villarreal Gómez, Facultad de Ciencias de la Ingeniería y Tecnología, Universidad
Autónoma de Baja California, Tijuana, México. Blvd. Universitario #1000. Unidad Valle de las Palmas. Tijuana, Baja
California, México. Postal Code: 22260. E-mail: luis.villarreal@uabc.edu.mx. ORCID: 0000-0002-4666-1408.
Recibido: 8 de Septiembre del 2020 Aceptado: 27 de diciembre del 2020 Publicado: 28 de Diciembre del 2020
Abstract. – The search for suitable bone remplacement its of great importance due to the difficulty to use
autologous transplants. Hence, the objective of this work is to compare the temperature effect on the
porosity and average pore diameter of hydroxyapatite porous scaffolds fabricated by the salt leaching
method. Hydroxyapatite porous scaffolds fabricated by the salt leaching technique were sintered from
~150 to 1000 °C. Synthesized hydroxyapatite was assessed by X-ray diffraction (XRD). Zeta potential at
different temperatures was evaluated. Specimens were characterized using scanning electron microscopy
(SEM) and Raman analysis. The results showed that significant porosity (57%) and pore size (49 µm)
occurred with a thermal treatment above ~ 850 °C for scaffolds that were pre-sintered at 1050 °C.
Keywords: Hydroxyapatite; porous scaffold; salt leaching method.
Resumen. - La búsqueda de un reemplazo óseo adecuado es de gran importancia debido a la dificultad
de utilizar trasplantes autólogos. Es por esto, que el objetivo de este trabajo es comparar el efecto de la
temperatura sobre la porosidad y el diámetro promedio de poro fabricados con el método de lixiviación
de sales, siendo sinterizados desde ~150 a 1000 °C. Los andamios fabricados de hidroxiapatita fueron
evaluados con difracción de rayos X (XRD). El potencial zeta fue evaluado a diferentes temperaturas. Los
especímenes fueron caracterizados utilizando microscopia electrónica de barrido (SEM) y análisis
Raman. Los resultados mostraron que la porosidad importante (57%) y tamaño de poro (49 µm) ocurren
con un tratamiento térmico superior a ~ 850 °C para andamios que fueron pre-sinterizados a 1050 °C.
Palabras clave: Hidroxiapatita; andamios porosos; método de lixiviación de sales.
Revista de Ciencias Tecnológicas. Volumen 3 (4): 213-221
214
ISSN: 2594-1925
1. Introduction
In tisssue enginneering applications, autologous
bone grafting procedure is the current treatment
for bone injuries, but this procedure has several
limitations, which include additional surgical
procedures, chronic pain after surgery, donor site
morbidity and lack of tissue availability [1]. To
overcome the problems associated with autograft
use, alloplastic materiales have been developed.
Alloplastics are materials with unlimited
availability, no risk of disease transmission and
osteoconductive properties [2]. The most
common alloplastic material used in biomedical
applications is hydroxiapatite [3].
The use of hydroxyapatite as porous scaffolds or
as a bioactive coating material in medical devices
is justified because ceramics resist oxidation and
corrosion in the physiological environment and
possess great resistance to friction and wear;
however, hydroxyapatite by itself has poor
biomechanical properties, its ability to withstand
flexion and compression stresses is very low,
causing it to fracture easily. Given these
drawbacks, in recent decades several organic
compounds of the extracellular matrix such as
fibronectin, vitrionectin, osteopontin, growth
factors and type I collagen, among others, have
been added to hydroxyapatite coatings in order to
improve osteoconduction, cell adhesion and the
mechanical properties of the coating [4-9]. A
relatively new promising material that can
improve the mechanical properties of the coating
is graphene [10], since it has great flexibility and
mechanical rigidity, in addition to its properties
as an electrical conductor that could help coating
methods based on voltage, such as
electrodeposition and electrophoresis [11, 12].
It has been reported that the most suitable pore
size for optimal vascularization is 100-500 µm,
which also provides an area of adhesion to
osteogenic cells [13, 14], and that percentage
porosity values above 10% in ceramic materials
indicate pore interconnectivity, the more
percentage of porosity, the more probability of
pore interconnection. The porosity values present
in trabecular bone vary between 30 and 90% with
interconnected porosity between 50 and 90%.
The more porosity and interconnectivity, the
more ease of cell proliferation and migration,
aswell as greater nutrient transport [15].
The objective of this work is to compare the
temperature effect on the porosity and average
pore diameter of HAp porous scaffolds
manufactured by the salt leaching method, were
this technique is easy to perform, affordable and
promote the pososity of a compressed inorganics
powders as hydroxyapatite.
2. Methodology
2.1. Materials
Distilled water (H
2
Od) (Arrowhead), 85%
phosphoric acid (H
3
PO
4
), calcium hydroxide (Ca
(OH)
2
) and potassium chloride (KCl) were
obtained from Fermont and used as received.
2.2. Hydroxyapatite (HAp) synthesis
Hydroxyapatite powder (HAp) was synthesized
using the methodology reported by Guillen-
Romero, L, et al. [16], were an H
3
PO
4
solution
was blended with Ca (OH)
2
w/v in a relation
1:1.67 with a constant stirring during 7 days.
After that, the solution was washed 3 times by
centrifugation at 3000 rpm for 5 min. The pellet
was resuspended and filtered off through
Buchner funnel and washed again with ethanol.
The filtered sample was left to dry at 80 ᵒC for 5
days in an oven. Finally, half a gram of the
resulting HAp was sintered at four different
temperatures (~150 ° C, ~450 ° C, ~850 ° C and
~1000 ° C) for 2 h to observe the influence of the
temperature on the fabrication of the sintered
hydroxyapatite (sHA) scaffolds [16, 17].
Revista de Ciencias Tecnológicas. Volumen 3 (4): 213-221
215
ISSN: 2594-1925
2.3. HAp and sHA porous scaffold preparation
Potassium chloride (KCl) was added to HAp and
sHA in a KCl/HAp-sHA (1/1.85 w/w). The
mixture was homogenized by grinding them
together in a porcelain mortar. Then, the samples
were compacted using a hydraulic press into
cylindrical scaffolds with a force of 5000 lbs for
2 min. HAp and sHA scaffolds were sintered in
different temperatures ranging from ~150 to
1000 °C for 2 h in an oven. Finally, HAp and
pHA scaffolds were placed in a drip leaching
system. The volume of liquid solvent used in the
leaching process was 10 mL of distilled water for
all samples. All sHA scaffolds disintegrated in
contact with water during the drip leaching
process. However, HAp scaffolds maintained
their consistency. For this reason, the drip-
leaching process was only applied to the HAp
scaffolds [16, 18].
2.3. Anaylisis characterization
2.3.1. X-ray diffraction (XRD)
The equipment used for this analysis was the
Bruker D8 Advance diffractometer, with the
powder methodology. A metallic holder was
used, and was set with few samples, enough to
cover the surface of the holder (1 cm lenght x 3
mm width). After that, the holder was located
inside the equipment with the following
conditions: 15 and 30 rpm, lamp of copper (Cu)
at 30 kV [16].
2.3.2. Raman spectroscopy
In the case of Raman spectroscopy, it was
analyzed using an FRA 106/S FT-Raman, Bruker
with an Nd: Y AG laser source operating at 1200
nm with a 180° back scattering geometry,
spectral width 1 cm
−1
, and power of the laser
beam 250 mW reaching the sample [19].
2.3.3. Scanning electron microscopy (SEM)
Specimens were characterized by scanning
electron microscopy (SEM). SEM images were
obtained using secondary electron detector
(SED). Percentage of porosity and average pore
diameter were measured using the software Fiji
ImageJ using images with a magnification of
1000 x.
2.3.4. Z potential studies
A Z potential analysis was performed using the
HORIBA SZ-100 zetameter by taking 1 mg of
the hydroxyapatite, 1 mmol of KCl and
dissolving them in 100 mL of 70% ethanol using
the BRANSONIC 2510R-MT sonifier. To
determine the particle size, the same equipment
was used with a solution of 10 mg in 100 mL of
ethanol. Both Z potential and particle size
analysis of HAp treated at different temperatures
were also determined. For that, 1 gr of HAp,
0.001 mol of KCl and 100 mL of 70 % ethanol
were used in order to make the Z potential
analysis and 10 mL of HAp with 100 mL of
ethanol were used in the particle size analysis.
Misonix Branson 2510R-MT ultrasonic cleaner
was used to mix the samples [16].
3. Results and Discussions
3.1. Raman spectroscopy
The Raman spectrum showed in figure 1, that the
obtained signals are according with literature
[16-18], demonstrating the HAp presence in the
samples, validating its synthesis.
In the Raman spectra all signals were assigned to
the internal vibrational modes of the PO
4-
group.
The intense signal at 960 cm
−1
matches with the
symmetric stretching mode ν1 of the tetrahedron
PO
4
−3
group (P-O bond); the weak peak around
600 cm
−1
is assigned to the triple bending mode
ν4 of PO
4
−3
(O-P-O bond); the double
degenerative bending mode ν2 of the PO
4
−3
Revista de Ciencias Tecnológicas. Volumen 3 (4): 213-221
216
ISSN: 2594-1925
group (O-P-O bond) can be observed as a
medium peak at 440 cm
−1
[19-21].
Figure 1. Raman spectrum of hydroxyapatite.
3.2. X-ray diffraction (XRD) analysis
Figure 2, shows the diffraction pattern, were 4
greater signals of intensity located at the left of
the spectra between the angular zone 20 <2θ <80
were assigned corresponding to the Miller
indexes of (002), (211), (112), (300) (red circle).
Despite that those indices are attributed to
hydroxyapatite, the lack of separated signals with
lower strength indicate a low crystallinity [18,
22, 23]. However, a comparison between the
obtained HAp patterns with JCPDS 09-432 file
shows that HAp obtained in this work represents
the typical hydroxyapatite sign.
Figure 2. XRD spectrum of HAp. JCPDS 009-0432.
3.3. Scanning electron microscope (SEM)
The microstructure of HAp and sHA porous
scaffolds was examined using scanning electron
microscopy “figure 3 A-C” and “figure 3 E-G”
respectively. The heat treatment applied to HAp
and sHA scaffolds were carried out using
temperatures from ~150 to 1000 °C. Porosity and
pore size were estimated using the ImageJ
software “table 1”.
Revista de Ciencias Tecnológicas. Volumen 3 (4): 213-221
217
ISSN: 2594-1925
Figure 3. Micrographies of sHA scaffolds with different heat treatment for 2 hours at 15 KV of magnification. (A) ~150 ᴼC at
2 h (B) ~850 ᴼC at 2 h (C) ~1000 ᴼC at 2 h (D) ~150 ᴼC at 24 h (E) ~850 ᴼC at 24 h (F) ~1000 ᴼC at 24 h.
Table 1. Temperature effect on the porosity and average pore diameter of HA porous scaffolds. HAp (hydroxyapatite without
sintering) sHA (hydroxyapatite sintered at 1000 °C).
Sample
Porosity %
Average pore diameter
µm
Min
Max
HAp 150
13
70 ±41
25
169
HAp 850
57
43 ±37
10
248
HAp 1000
52
100 ±64
19
308
sHA 150
50
47 ±27
9
163
sHA 850
57
49 ±28
11
151
sHA 1000
49
48 ±34
9
186
“Table 1” shows the effect of temperature on the
sHA. Porous scaffolds at ~150 °C produced less
percentage of porosity than the other two sHA
scaffolds exposed at ~850 and ~1000 °C. Both
porosity and average pore diameter of HAp and
sHA scaffolds treated at ~850 °C showed great
similarity. A porosity of 57 % was obtained in
HAp and sHA scaffolds treated at 850 °C.
Based on the results obtained by scanning
electron microscopy, it is concluded that all
specimens that were evaluated presented pore
interconnectivity based in the fact that
percentage porosity in both HAp and sHA
scaffolds were above 10 %. According to some
studies, porosity values above 10 % indicate
interconnectivity between pores in ceramic
materials [22] and a higher porosity translates
into higher cellular proliferation and nutrient
transport.
In addition, microporosity and macroporosity
was perceived in all samples. Pores between 9
and 308 µm were found. Sequeda reported that
the most suitable pore size range for ease of cell
Revista de Ciencias Tecnológicas. Volumen 3 (4): 213-221
218
ISSN: 2594-1925
proliferation and migration varies between 100-
500 μm [23].
Thermal treatment at higher temperature
(~1000°C) of HAp scaffolds resulted in a
considerable increase of average pore diameter
compared with the rest. It can be observed, that
the particle size of HAp decreases when the
temperature increment. The particle size results
are shown in “table 2”.
Table 2. Particle size of hydroxyapatite (HA and HAS).
Particle size [µm]
30 ± 3
12 ± 1
11 ± 0.4
11 ± 0.5
8 ± 0.2
Brown, C. et al., 2015, demonstrated that particle
size its an important factor that impact stem cell
differentiation through cell–cell and cell–matrix
interactions [24]. With the thermal treatments of
the sHA it was achieved a low particle size
diameter (~8-12 µm), which are interesting sizes
for tissue engineering [24]. At ~1000° C where
obtained the lowest particle size (~8 µm). In the
case of the particle size obtained (~30 µm) from
the HAp, its higher size can be attributed to the
existence of coordinated H
2
0 molecules that
remain when were allowed to dry at a
temperature of ~80 °C. The particle size is
suitable to use in coatings [16], because at a size
of 10 µm allows cell adhesion, however, is not as
feasible to be used in other medical applications,
because the size of the particle would complicate
of the construction of seeding channels in the
bone.
3.4. Z potential analysis
On the other hand, low zeta potentials values
promote the differentiation of osteogenic cells at
the surface’s material and negatively charged
surfaces have excellent biocompatibility [25].
Table 3 show the lowest zeta potential results for
HAp at higher temperature. At the opposing, the
effect of heat temperature on HAp and sHA at
~150 °C produced less percentage of porosity
and higher zeta potential compared to ~850 and
~1000 °C treatments. As a result, sHA scaffolds
treated at ~1000 °C can have potential properties
for cell adhesion and proliferation [26-28].
Table 3. Z potential of Hydroxyapatite (HAp and sHA). Ethanol was used to prepared HA solutions for the Z potential analysis.
All solutions were adjusted at pH of 7.5.
Sample
Z Potential [mV]
Electrophoretic
movility [cm
2
/Vs]
Conductivity
[mS/cm]
No termal treatment (HAp)
-18 ± 4
-31 10
-6
± 7 10
-6
0.109
sHA150 (~150 °C)
-19 ± 3
-37 10
-6
± 7 10
-6
0.109
sHA450 (~450 °C)
-22 ± 2
-44 10
-6
± 3 10
-6
0.102
sHA850 (~850 °C)
-15 ± 2
-30 10
-6
± 5 10
-6
0.110
sHA1000 (~1000 °C)
-27 ± 2
-54 10
-6
± 4 10
-6
0.112
Revista de Ciencias Tecnológicas. Volumen 3 (4): 213-221
219
ISSN: 2594-1925
According to a study, the Z potential value for
hydroxyapatite at this pH should be in the range
of 15 mV as seen in the sintered sample at ~850
°C, however given the favorable results of the
sample at ~1000 °C [16].
4. Conclusions
The porosity and average pore diameter of HA
porous scaffolds fabricated by the salt leaching
method can be controlled by thermal treatments.
In this work, hydroxyapatite was successfully
synthesized using the wet precipitation method.
The higher porosity ratio was obtained at ~850
°C treatment, but lower Z potential of HAp was
at ~1000 °C indicating that any of these two sHA
sample can be adequate cell adhesion and
proliferation properties. Further studies have to
be done to find a balance with adequate %
porosity and lower z potential.
Its important to denote, that all the obtained HAp
and sHA scaffolds presented a superior porosity
than 30 %, been suitable for trabecular bone
replacement applications. Still, future tests are
necessary to complement this study in order to
propose these HAp and sHA scaffolds for tissue
engineering applications.
5. Acknowledgments
The authors are grateful to Universidad
Autónoma de Baja California, with the registered
SICASPI-UABC project 351/2420. Moreover,
the authors thanks to Alan Saul Alvarez Suarez
for revision of the English in the manuscript.
References
[1] K. Yang et al., “β-Tricalcium
phosphate/poly (glycerol sebacate) scaffolds
with robust mechanical property for bone tissue
engineering,” Mater. Sci. Eng. C, vol. 56, pp. 37–
47, Nov. 2015.
http://dx.doi.org/10.1016/j.msec.2015.05.083.
[2] Z. Sheikh, C. Sima, and M. Glogauer,
“Bone Replacement Materials and Techniques
Used for Achieving Vertical Alveolar Bone
Augmentation,” Materials, vol. 8, no. 6. 2015.
http://dx.doi.org/10.3390/ma8062953.
[3] J. Lindhe. Periodontologia Clinica E
Implantologia Odontologica. Médica
Panamericana; 2009.
https://books.google.com.mx/books?id=69zuJ1q
spGwC.
[4] L. J. Villarreal-Gómez et al.,
“Biocompatibility evaluation of electrospun
scaffolds of poly (L-Lactide) with pure and
grafted hydroxyapatite,” J. Mex. Chem. Soc.,
vol. 58, no. 4, pp. 435–443, 2014.
http://dx.doi.org/10.29356/jmcs.v58i4.53.
[5] G. Hannink and J. J. C. Arts,
“Bioresorbability, porosity and mechanical
strength of bone substitutes: What is optimal for
bone regeneration?” Injury, vol. 42, pp. S22–
S25, Dec. 2016.
http://dx.doi.org/10.1016/j.injury.2011.06.008.
[6] C. T. I. Reviews, Biomaterials Science, An
Introduction to Materials in Medicine. Cram101,
2016.
https://books.google.com.mx/books?id=TdrIAQ
AAQBAJ.
[7] R. Bosco, J. Van Den Beucken, S.
Leeuwenburgh, and J. Jansen, “Surface
Engineering for Bone Implants: A Trend from
Passive to Active Surfaces,” Coatings, vol. 2, no.
3. 2012.
http://dx.doi.org/10.3390/coatings2030095.
[8] L. J. Villarreal-Gómez et al., In vivo
biocompatibility of dental scaffolds for tissue
regeneration, vol. 976. 2014.
http://dx.doi.org/10.4028/www.scientific.net/A
MR.976.191.
[9] K. Kuroda and M. Okido, “Hydroxyapatite
Coating of Titanium Implants Using
Hydroprocessing and Evaluation of Their
Osteoconductivity,” Bioinorg. Chem. Appl., vol.
2012, no. 1, pp. 1–7, 2012, doi:
http://dx.doi.org/10.1155/2012/730693.
[10] C. Berger et al., “Ultrathin Epitaxial
Graphite: 2D Electron Gas Properties and a
Route toward Graphene-based Nanoelectronics,”
J. Phys. Chem. B, vol. 108, no. 52, pp. 19912–
Revista de Ciencias Tecnológicas. Volumen 3 (4): 213-221
220
ISSN: 2594-1925
19916, Dec. 2004.
http://dx.doi.org/10.1021/jp040650f.
[11] L. Chen, Y. Tang, K. Wang, C. Liu, and S.
Luo, “Direct electrodeposition of reduced
graphene oxide on glassy carbon electrode and its
electrochemical application,” Electrochem.
commun., vol. 13, no. 2, pp. 133–137, Feb. 2011.
http://dx.doi.org/10.1016/j.elecom.2010.11.033.
[12] J. Shi, X. Li, G. He, L. Zhang, and M. Li,
“Electrodeposition of high-capacitance 3D
CoS/graphene nanosheets on nickel foam for
high-performance aqueous asymmetric
supercapacitors,” J. Mater. Chem. A, vol. 3, no.
41, pp. 20619–20626, 2015.
http://dx.doi.org/10.1039/C5TA04464B.
[13] A. Di Luca et al., “Gradients in pore size
enhance the osteogenic differentiation of human
mesenchymal stromal cells in three-dimensional
scaffolds,” Sci. Rep., vol. 6, p. 22898, Mar. 2016.
http://dx.doi.org/10.1038/srep22898.
[14] C. M. Murphy and F. J. O’Brien,
“Understanding the effect of mean pore size on
cell activity in collagen-glycosaminoglycan
scaffolds,” Cell Adh. Migr., vol. 4, no. 3, pp.
377–381, Dec. 2010.
http://dx.doi.org/10.4161/cam.4.3.11747.
[15] P. Kasten, I. Beyen, P. Niemeyer, R.
Luginbühl, M. Bohner, and W. Richter, “Porosity
and pore size of β-tricalcium phosphate scaffold
can influence protein production and osteogenic
differentiation of human mesenchymal stem
cells: An in vitro and in vivo study,” Acta
Biomater., vol. 4, no. 6, pp. 1904–1915, Nov.
2008.
http://dx.doi.org/10.1016/j.actbio.2008.05.017.
[16] L. D. Guillen-Romero et al., “Synthetic
hydroxyapatite and its use in bioactive coatings,”
J. Appl. Biomater. Funct. Mater., vol. 17, no. 1,
2019.
http://dx.doi.org/10.1177/2280800018817463.
[17] J. Wosek, “Fabrication of Composite
Polyurethane/Hydroxyapatite Scaffolds Using
Solvent-Casting Salt Leaching Technique,”
Advances in Materials Science, vol. 15. p. 14,
2015. http://dx.doi.org/10.1515/adms-2015-
0003.
[18] S. Fragoso Angeles, R. Vera-Graziano, G.
L. Pérez González, A. L. Iglesias, L. E. Gómez
Pineda, and L. J. Villarreal-Gómez, “Síntesis y
Caracterización de Hidroxiapatita Sintética para
la Preparación de Filmes de PLGA/HAp con
Potencial Uso en Aplicaciones Biomédicas,”
ReCIBE, vol. 7, no. 2, pp. 93–116, 2018.
http://recibe.cucei.udg.mx/ojs/index.php/ReCIB
E/article/view/94.
[19] S. Koutsopoulos, “Synthesis and
characterization of hydroxyapatite crystals: a
review study on the analytical methods”. J
Biomed Mater Res. Vol. 62, Pp. 600–612, 2002.
https://doi.org/10.1002/jbm.10280
[20] A.F. Khan, M. Awais, A.S. Khan, “Raman
spectroscopy of natural bone and synthetic
apatites”. Appl Spectrosc Rev. Vol. 48, Pp. 329–
355, 2013.
https://doi.org/10.1080/05704928.2012.721107
[21] G.R. Sauer, W.B. Zunic, J. R. Durig,
“Fourier transform Raman spectroscopy of
synthetic and biological calcium phosphates”.
Calcif Tissue Int. Vol. 54, Pp. 414, 1994.
https://doi.org/10.1007/BF00305529
[22] A.-J. Wang et al., “Effect of sintering on
porosity, phase, and surface morphology of spray
dried hydroxyapatite microspheres,” J. Biomed.
Mater. Res. Part A, vol. 87A, no. 2, pp. 557–562,
2008, http://dx.doi.org/10.1002/jbm.a.31895.
[23] S. V Dorozhkin, “Calcium orthophosphate
deposits: Preparation, properties and biomedical
applications,” Mater. Sci. Eng. C, vol. 55, pp.
272–326, Oct. 2015, doi:
http://dx.doi.org/10.1016/j.msec.2015.05.033.
[24] C. F. C. Brown, J. Yan, T. T. Y. Han, D. M.
Marecak, B. G. Amsden, and L. E. Flynn, “Effect
of decellularized adipose tissue particle size and
cell density on adipose-derived stem cell
proliferation and adipogenic differentiation in
composite methacrylated chondroitin sulphate
hydrogels,” Biomed. Mater., vol. 10, no. 4, p.
45010, 2015, http://dx.doi.org/10.1088/1748-
6041/10/4/045010.
[25] D. N. Misra, Adsorption on and Surface
Chemistry of Hydroxyapatite. Springer US,
2013.
Revista de Ciencias Tecnológicas. Volumen 3 (4): 213-221
221
ISSN: 2594-1925
https://books.google.com.mx/books?id=uDHvB
wAAQBAJ.
[26] M. Morga, Z. Adamczyk, and M. Oćwieja,
“Stability of silver nanoparticle monolayers
determined by in situ streaming potential
measurements,” J. Nanoparticle Res., vol. 15, no.
11, p. 2076, Oct. 2013.
http://dx.doi.org/10.1007/s11051-013-2076-5.
[27] P. de Vos, B. J. de Haan, J. A. A. M.
Kamps, M. M. Faas, and T. Kitano, “Zeta-
potentials of alginate-PLL capsules: A predictive
measure for biocompatibility?” J. Biomed.
Mater. Res. Part A, vol. 80A, no. 4, pp. 813–819,
2007. http://dx.doi.org/10.1002/jbm.a.30979.
[28] D. Malina, K. Biernat, and A. Sobczak-
Kupiec, “Studies on sintering process of
synthetic hydroxyapatite,” Acta Biochim. Pol.,
vol. 60, no. 4, pp. 851–855, 2013.
http://www.actabp.pl/pdf/4_2013/851.pdf.
[29] J. González Ocampo, D. M. Escobar Sierra,
and C. P. Ossa Orozco, “Métodos de fabricación
de cuerpos porosos de hidroxiapatita, revisión del
estado del arte,” Revista ION, vol. 27. scieloco,
pp. 55–70, 2014.
https://revistas.uis.edu.co/index.php/revistaion
[30] M. Sadat-Shojai, M.-T. Khorasani, E.
Dinpanah-Khoshdargi, and A. Jamshidi,
“Synthesis methods for nanosized
hydroxyapatite with diverse structures,” Acta
Biomater., vol. 9, no. 8, pp. 7591–7621, Aug.
2013.
http://dx.doi.org/10.1016/j.actbio.2013.04.012.
Este texto está protegido por una licencia Creative Commons 4.0
Usted es libre para Compartir —copiar y redistribuir el material en cualquier medio o formato — y Adaptar el documento —remezclar,
transformar y crear a partir del material— para cualquier propósito, incluso para fines comerciales, siempre que cumpla la condición de:
Atribución: Usted debe dar crédito a la obra original de manera adecuada, proporcionar un enlace a la licencia, e indicar si se han realizado
cambios. Puede hacerlo en cualquier forma razonable, pero no de forma tal que sugiera que tiene el apoyo del licenciante o lo recibe por el uso
que hace de la obra.
Resumen de licencia - Texto completo de la licencia