Growth Of Hydroxyapatite Research Articles

Investigation on physicochemical properties of graphene oxide/nano-hydroxyapatite composites and its biomedical applications

Graphene oxide/nano-hydroxyapatite (GO/nHAP) composites were synthesized by simultaneous titration method. The GO powder was uniformly dispersed ultrasonically in a solution containing Ca(NO3)2. It was co-titrated with (NH4)2HPO4, during which NH3·H2O was used to maintain pH of about 10. Transmission electron microscopy (TEM) showed that HAP had a drusy acicular crystal structure with 100–200 nm length in the composite. The Ca2+ ions were attracted by the negatively charged oxygen functional groups present on GO sheets. They also oriented the growth of hydroxyapatite preferentially along (112) plane, which was also consistent with X-ray diffractometry (XRD) results. According to X-ray photoelectron spectroscopic (XPS) results, the peak intensities of the C–O and C–C groups increased in the GO/nHAP composite. However, the number of –COO– and C–O–C groups was reduced as well as the position of peaks shifted due to electrostatic interactions. These results were also corroborated with Fourier transform infrared spectroscopy (FTIR). MTT assay indicated that GO/nHAP composites had a significant effect on proliferation of 293T cells and good biomimetic mineralization as shown by in vitro bioactivity assays. EDS spectroscopy confirmed that the Ca/P ratio in calcium phosphate deposits was 1.62, which was close to the ratio of 1.64 in natural bone. The biological performance of GO/nHAP composite proved it to be a promising candidate for bone regeneration and implantation.

Fabrication of biocomposite sheets from silk cocoons for tissue engineering applications

Silk based biomaterials have been explored as a natural-based system for tissue regeneration. Biocomposite sheets were fabricated by controlled deposition of hydroxyapatite (HA) on porous silk cocoon structure through precipitation method using calcium chloride dihydrate and disodium hydrogen phosphate anhydrous solutions. The formation of hydroxyapatite coating on the silk sheets was confirmed by the presence of characteristic apatite peaks in the XRD patterns. The interactions between HA and silk proteins were evidenced by a shift in the amide peaks of biocomposites as observed from the IR spectra. The mineralisation of silk sheets did not alter their thermal stability as revealed from the thermogravimetric analysis. Scanning electron microscopy of the silk sheets showed the growth of hydroxyapatite on the surface of fibrous silk networks. The tensile strength of the biocomposite sheets is decreased to 21-30 MPa when compared to native silk sheets that had 32 MPa. The properties of silk cocoon-hydroxyapatite biocomposite sheets indicate its potential as a suitable substrate for bone tissue engineering application.

Titanium-Tantalum Alloy Surface Modification by Hydroxyapatite Layer on TiO2 Nanotubes: Effect on Microbial Activity

Abstract One of the major health security challenges of the 21st century is the occurrence of microbial infections and bacterial complications that could affect 10 million people by 2050. On the biomaterial field, implant metallic currently replaces partial or total body parts and can fail to be integrated into the body due to infections. This study performs two combined surface modifications on Ti-30Ta alloy, in order to obtain an infection-resistance and osseointegration surface on metallic implants to be tested within bacterial biofilm. The Group 1 investigated surface modifications by the anodization process in the electrolyte glycerol + NH4F 0.25% at 30V- 9 hours and annealed in 530°C (5°C/min). The Group 2 underwent the same process as Group 1 and, additionally, the samples were immersed in 0.3 M CaCl2 and 0.5 M Na2HPO4 solutions for hydroxyapatite growth. The substrate was characterized using scanning electron microscopy (SEM), X-ray diffractometer (XRD) and dynamic contact angle. S. epidermidis bacterial adhesion and biofilm formation. The results indicated that the Group 1 shows a higher antimicrobial activity, hydrophilic behavior and potential to be used for metallic implant applications. The Group 2 with the hydroxyapatite film coating did not have an improvement in the antimicrobial response.

Controlled Anisotropic Growth of Hydroxyapatite by Additive-Free Hydrothermal Synthesis

The synthesis of hydroxyapatite (HAp) with different shapes and sizes has attracted increasing attention because the applicability of this ceramic material depends on structure-properties relations...

The pH Effect on the Growth of Hexagonal and Monoclinic Hydroxyapatite Synthesized by the Hydrothermal Method

Summary. In the present work, a study of H+ effects on the microstructure and morphology of hydroxyapatite synthesized by the hydrothermal method is reported. The synthesis was realized with pH values of 10, 9.6, 9, 8, and 7. To know the particle size distribution, growth habit, chemical composition, and crystalline phases present, SEM-EDS, XRD, AFM, and FTIR spectroscopy techniques were used and completed with Rietveld analysis. The obtained results showed an important effect of H+ on the morphological and crystallographic characteristics of the hydroxyapatite, demonstrating that the shape and nanoparticle size, as well as the number of crystalline phases, can change depending on the pH during the synthesis. It was observed that there is an increase in the formation of the monoclinic phase and a decrease of the hexagonal phase when the pH value diminishes from 9.6 to 7. The crystallite size also decreases from 46.69 to 19.56 nm. An explanation of the role of pH on the final characteristics of the hydroxyapatite was related to the amount of H+ and OH- ions, and it was included in this work.

Development of composite hydrogel based on hydroxyapatite mineralization over pectin reinforced with cellulose nanocrystal

Hydrogels based on pectin and cellulose nanocrystals (CNC) were used in our study to nucleation and growth of hydroxyapatite (HAp) by the biomimetic method. In this study, we evaluated the direct impact of the different percentages of CNC on pectin hydrogel and the influence of HAp obtained through two methods. CNC were obtained from HCl hydrolysis following chemical functionalization through vinyl groups. The percentage of CNC positively induces thermal stability, mechanical properties and HAp mineralization from biomimetic using simulated body fluid (1.5 SBF). Hydrogels with 5% of CNC showed a higher amount of HAp immersed for 14 days, about 28% of HAp. The obtained hydrogels were compared with hydrogels containing 20% of HAp nanoparticles obtained by chemical precipitation. Biocompatibility of the hydrogels was evaluated by cell viability using fibroblasts (L929). In general, the hydrogels obtained through the biomimetic method show slightly larger biocompatibility compared to the hybrid hydrogels obtained from chemical precipitation.

Pyrophosphates in toothpaste: a retrospective and reappraisal.

During the last 50 years, an increasing number of toothpastes have been marketed that include pyrophosphates as anti-tartar (calculus) agents. Pyrophosphates are chelating agents with low toxicity and a broad range of applications, such as food additives and in industrial applications. Like other chelating agents, the prime function is to combine with metal elements and, in toothpastes, to inhibit calcium phosphate deposits in the form of dental calculus. It is well established that pyrophosphates inhibit crystal growth of hydroxyapatite in bones and teeth, and theoretically may negatively affect the demineralisation-remineralisation equilibrium at the tooth surface. Surprisingly, little clinical research has been carried out to assess if the caries protection provided by fluoride toothpaste is compromised by the inclusion of pyrophosphates and the existing evidence is inconsistent. In the absence of more clinical research, it is suggested that children should not use pyrophosphate-containing toothpastes under 12 years of age.

Intermolecular channels direct crystal orientation in mineralized collagen

The mineralized collagen fibril is the basic building block of bone, and is commonly pictured as a parallel array of ultrathin carbonated hydroxyapatite (HAp) platelets distributed throughout the collagen. This orientation is often attributed to an epitaxial relationship between the HAp and collagen molecules inside 2D voids within the fibril. Although recent studies have questioned this model, the structural relationship between the collagen matrix and HAp, and the mechanisms by which collagen directs mineralization remain unclear. Here, we use XRD to reveal that the voids in the collagen are in fact cylindrical pores with diameters of ~2 nm, while electron microscopy shows that the HAp crystals in bone are only uniaxially oriented with respect to the collagen. From in vitro mineralization studies with HAp, CaCO3 and γ-FeOOH we conclude that confinement within these pores, together with the anisotropic growth of HAp, dictates the orientation of HAp crystals within the collagen fibril.

Simultaneous improvement of corrosion resistance and bioactivity of a titanium alloy via wet and dry plasma treatments

The fabrication of bioactive oxide layers on Ti–6Al–4V alloy by combining of wet and dry plasma methods for optimizing the chemical stability and biological activity together was reported. To achieve this goal, dry plasma sputtering depositions of Mg and Zn in the RF and DC modes, respectively, were performed for 5 and 20 min on the surface of titanium oxide obtained by wet plasma electrolytic oxidation of Ti–6Al–4V alloy substrate. Zn and Mg particles were successfully introduced into the titanium oxide layer which not only leads to decrease the fraction and size of microdefects but also increases the fraction of biocompatible anatase phase in compassion to that in the un-sputtered oxide layer. The corrosion resistance of sputtered oxide layers was superior to the un-sputtered layer. Regarding the hydroxyapatite formation and cell proliferation, Zn and Mg particles incorporated in less amounts in the sample sputtered for 5 min were of considerable significance in facilitating the nucleation and growth of hydroxyapatite and proliferation of MC3T3-E1 on the surface of this sample. Thus, the oxide layer containing Zn and Mg particles would be used as a promising implant material due to its great intrinsic chemical stability and osteointegration ability.

Entrapment of collagen on polylactic acid 3D scaffold surface as a potential artificial bone replacement

A new potential biomimetic polymeric 3D scaffold is fabricated using collagen entrapment and 3D printed polylactic acid scaffold. The modified scaffold was characterized by compressive modulus, degree of swelling, water contact angle (WCA), and Fourier Transform Infrared Spectroscopy (FTIR). The findings show that sample PLA/col40 with 40 s entrapment duration is the optimum composition that meets the requirement for artificial bone tissue replacement. In vitro biomineralization using simulated body fluid (SBF) demonstrates that the PLA/collagen 3D scaffold is able to promote the growth of hydroxyapatite (HA) after 7 days which will subsequently improve the osteoconductive and osteoinductive properties of the 3D scaffold. The overall results suggest the potential of the 3D PLA/collagen scaffold as a prospective material for bone tissue engineering applications.

In vitro bioactivity and osteoblast cell viability studies of hydroxyapatite-incorporated silica aerogel

Bioactivity and osteoblastic growth of hydroxyapatite (HA)-incorporated silica aerogels (SA) (HAESA) with different ratio of HA/SiO2 (0.1, 0.5, 1.0, and 1.3 HA/SiO2) were investigated. Bioactivity of HAESA was studied by immersing all samples in simulated body fluids (SBF) for 7 and 14 days. The recovered samples were then characterised using Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy combined with energy dispersive X-ray analyser (FESEM–EDX) and the analysis of phosphate loss in the solution. These samples were also investigated for their effect on cell viability and proliferation abilities against normal human osteoblast cells in vitro after 24 and 48 h of exposure times. The HA/SiO2 ratio affected its bioactivity in which the bioactivity increased to 0.5 (HAESA-0.5) and declined at higher ratios (1.0 and 1.3). A similar trend was observed for cell viability and proliferation assays. HAESA-0.5 (HA/SiO2 ratio of 0.5), which possesses the optimal characteristics of SA and HA, resulted in the highest osteoblastic growth due to the synergistic effects between SA and HA. Thus, HAESA-0.5 could be an alternative biomaterial compared to silica- and HA-based biomaterials for bone implant application due to its higher bioactivity in SBF with the improved performance of osteoblast growth. Hydroxyapatite-incorporated silica aerogel with different weight ratio of HA/SiO2 (HAESA) was studied for their bioactivity in simulated body fluid and in vitro osteoblastic growth.

Phase and Microstructural Evolution of Calcium Aluminum Phosphate Cement for Potential Biological Applications: Effect of Aluminum Hydroxide Sources

Calcium aluminum phosphate cement (CAPC) requires a practical composition for biological applications. This research aims to investigate the effect of aluminum hydroxide sources (aluminum hydroxide, boehmite, and hydratable alumina), where SECAR 71 cement and phosphoric acid are in the composition, regarding the mechanical, biological, and microstructural properties of CAPC. In vitro assessments were evaluated by immersing the samples in simulated body fluid (SBF) solution for 7 days, 14 days, and 28 days, and by MTT testing (cytotoxicity of MG-63 cells). The results revealed that the composition including hydratable alumina was superior concerning the lowest final setting time (50 min), in situ formation and growth of hydroxyapatite on its surface, as well as the compressive strength which reaches to 42 ± 10 MPa after 28 days in SBF solution. However, regarding the cytotoxicity, the cements consisting of boehmite have priority. A more detailed biological analysis is recommended to evaluate the clinical application of CAPC.

In Situ Biomimetic Mineralization on ZIF-8 for Smart Drug Delivery.

The exploration of metal-organic frameworks (MOFs) with good biocompatibility and physiological stability as carrier platforms for biomedical applications is of great importance but remains challenging. Herein, we developed an in situ biomimetic mineralization strategy on zeolitic imidazolate framework (ZIF) nanocrystals to construct a drug release system with favorable cytocompatibility, improved stability, and pH responsiveness. With lysozyme (Lys) wrapped on the surface of Zn-based ZIF (ZIF-8), Lys/ZIF-8 could strongly bond metal ions to promote nucleation and growth of bone-like hydroxyapatite (HAp), leading to formation of HAp@Lys/ZIF-8 composites. In vitro investigations indicate that the composites with a hollow Lys/ZIF-8 core and a HAp shell exhibited a high drug-loading efficiency (56.5%), smart pH-responsive drug delivery, cytocompatibility, and stability under physiological conditions. The proposed biomimetic mineralization strategy for designing MOFs-based composites may open a new avenue to construct advanced delivery systems in the biomedical field.

Factors Influencing the Interactions in Gelatin/Hydroxyapatite Hybrid Materials.

The most severe problem in bone regeneration is the defect in the interface. We prepared four types of implantation scaffolds of crosslinked gelatin (GE)/hydroxyapatite (HAp) to study the factors influencing interface interactions, they are film-crosslinked GE scaffold, gel-crosslinked GE scaffold, solid-crosslinked GE/HAp scaffold and gel-crosslinked GE/HAp scaffold. HAp could penetrate the entire GE matrix completely in four successive steps: physical preparation of a gel; chemical crosslinking; incubation in modified simulated body fluid (m-SBF) and freeze-drying. The penetrative nucleation and growth of HAp and the influencing factors in the GE matrix were investigated to ameliorate the interface interactions between organic and inorganic layers. During development of penetrative nucleation and growth, a tight connection was built between organic and inorganic layers, B-type carbonated HAp was formed after incubation with m-BSF, and the apatite content could be controlled. In summary, enhanced interface relies on not only the pre-seeded hydroxyapatite (HAp) as crystal nuclei but also the sufficient space for ions with high concentration to diffuse in.

Preliminary studies of strontium and selenium binary doped CaO–SiO2–P2O5–MgO bioceramics for faster growth of hydroxyapatite and bone regeneration applications

Bioceramic compositions of xSrO.(43-x)CaO·40SiO2.ySeO3.(12-y)P2O5·5MgO (where x = 0,2,4,6 and 8 mol%, y = 0,1,2,3 and 4 mol%) have been synthesized by the sol gel method in the laboratory. The influence of selenium and strontium binary doping on structural and biological behavior has been evaluated by X-Ray Diffraction, Fourier Transform Infrared, Raman and Field Emission Scanning Electron Microscopy techniques. Samples synthesized by the sol gel route have shown the hydroxyapatite phase formation on 1st day of the immersion in the simulated body fluid. Degradation studies have been undertaken in both Citric Buffer and Phosphate Buffer Saline. Drug loading and release properties of the prepared samples have been evaluated by using gentamicin as an antibiotic. Antimicrobial properties have been explored for the samples against four microorganisms and yeast strain with the appreciable range of inhibition zones. Zeta potential studies have been employed to check the surface charge and the samples exhibited the negative charge in simulated body fluid. The studies of inhibitory effects of strontium and selenium on cancer cell lines have been undertaken by using human osteosarcoma MG63 cell line. The MTT assay was executed on leukocytes of the rat to assess the toxicity of all prepared samples on the normal cells. The significant effort has been undertaken to scrutinize the best chemical composition of implant material for successful utility for bone regeneration applications and patients suffering from osteosarcoma.

P1234SNF472 IMPROVES LIMB BLOOD PERFUSION AND WALKING ABILITY IN A PERIPHERAL ARTERY DISEASE VASCULAR CALCIFICATION RAT MODEL

Abstract Background and Aims Peripheral Artery disease (PAD) is a common vascular disease associated with functional impairment and increased risk of cardiovascular events in End Stage Kidney Disease (ESKD) patients undergoing dialysis. Poor limb salvage outcomes and high post-amputation mortality in hemodialysis (HD) patients highlight the need for earlier medical therapies. Cilostazol and pentoxifylline are approved for PAD. Their use in HD patients stays limited and cilostazol use requires caution in this population. Clinical studies demonstrate associations between arterial calcification and adverse outcomes in PAD patients. SNF472, a selective calcification inhibitor that interferes in the formation and growth of hydroxyapatite, is in Phase 3 for calciphylaxis treatment. This study aims to evaluate the effects of SNF472 on limb functional recovery and blood perfusion in a Vitamin D3 (VitD)-induced arterial calcification rat model. Method Arterial calcification was induced in 32 Sprague Dawley rats by 3 consecutive daily s.c. doses of 120 kIU/kg VitD. Rats were divided into four groups and treated during 12 days by: placebo s.c, placebo p.o, SNF472 (20 mg/kg/day, s.c.) or cilostazol (20 mg/kg/day, p.o.). An additional group of 8 rats without VitD received vehicle only (sham). Efficacy was evaluated at day 12 and 17 (5 days after treatment stop). Posterior limb blood perfusion was measured using Laser Doppler Imaging and limb walking ability was evaluated by measuring Maximum Walking Distance (MWD) and Maximum Walking Time (MWT) using a treadmill. Rats were sacrificed at day 26 (14 days after treatment stop), and aortas were collected for calcium analysis. Results VitD-induced arterial calcification was associated with decreased blood perfusion and impairment of limb walking ability (MWT and MWD) compared to sham. SNF472 reduced aorta calcification by 41% compared to placebo. No effects of cilostazol on vascular calcification were observed. The inhibition of calcification in SNF472-treated animals was associated with significant higher limb blood perfusion compared to placebo or Cilostazol (1.28 and 1.37-fold higher, respectively at day 12: p< 0.001) and it was translated into a significant improvement in walking ability compared to placebo (515±114 meters vs 334±187 meters, respectively: p<0.05). Conclusion SNF472 shows improvements in vascular calcification, blood perfusion and a functional parameter like walking distance in a PAD vascular calcification rat model. These results suggest that SNF472 may represent a new therapeutic approach for the treatment of PAD associated with high vascular calcification such as in renal disease.

P0884MYO-INOSITOL HEXAPHOSPHATE PEGYLATION IMPROVES BIOAVAILABILITY BUT REDUCES ITS ANTI-VASCULAR CALCIFICATION EFFECT IN RATS

Abstract Background and Aims Vascular calcification (VC) is a major contributor to increased morbidity and mortality in End Stage Kidney Disease (ESKD) patients undergoing dialysis. SNF472, a salt of inositol hexaphosphate (InsP6), is a selective calcification inhibitor that interferes in the formation and growth of ectopic hydroxyapatite (HAP). SNF472 is currently in Phase 3 clinical trials for the treatment of calciphylaxis in ESKD patients on dialysis. Inositol-1,2,3,5-tetraphosphate-4,6-bisPEG100 (InsP4bisPEG or INS3001) results from the PEGylation of inositol tetraphosphate (InsP4) with polyethylene glycol (PEG) 100. Our aim was to compare the relative bioavailability of SNF472 and InsP4bisPEG and their efficacy in the inhibition of calcification in silico, in vitro and in vivo. Method Subcutaneous (10 mg/kg) pharmacokinetics of InsP4bisPEG and SNF472 were assessed in Sprague Dawley (SD) rats. To evaluate the adsorption binding affinity (Eads) of SNF472, InsP4bisPEG and other inositol phosphates to the HAP crystal surface, computational studies were performed using Density Functional Theory calculations with DMOL3 (MS2016). The in vitro efficacy of the compounds was evaluated using a pharmacodynamic assay to measure the calcification potential of human plasma. An in vivo efficacy study (calcification induced by 3 consecutives daily s.c. administrations of 150 kIU/kg vitamin D3) was performed with SD rats receiving s.c. vehicle, or equimolar doses (36 µmol/kg) of SNF472 or InsP4bisPEG once daily. Results The PEGylation of inositol tetraphosphate in positions 4 and 6 increased the exposure and t1/2 of the compound when given subcutaneously compared to SNF472. Molecular modelling revealed that SNF472 binds to the HAP surface with higher affinity than InsP4bisPEG and INSP4 (ΔEads=-352 kcal/mol for SNF472, ΔEads=-177 kcal/mol for InsP4bisPEG and ΔEads=-146 Kcal/mol for InsP4, taking inositol as reference). These results were correlated with the inhibition of calcium phosphate crystallization in plasma in vitro. SNF472 treated animals presented significantly lower calcium levels in aorta, which were 38% and 55% lower than placebo and InsP4bisPEG treated animals, respectively. Conclusion The differential pharmacokinetic profile of InsP4bisPEG (INS3001) does not translate into higher, but lower, efficacy than SNF472 against vascular calcification when comparing equimolar doses.

Polyaniline-coated titanium oxide nanoparticles and simvastatin-loaded poly(ε-caprolactone) composite nanofibers scaffold for bone tissue regeneration application

Poly(ε-caprolactone) (PCL) nanofibers loaded with polyaniline coated titanium oxide nanoparticles (TiO2/PANI) and simvastatin (SIM) drug were produced by the electrospinning method. As-prepared samples were investigated in terms of morphology characterization, mechanical properties, physiochemical properties, drug release, biomimetic mineralization, and biocompatibility. in vitro drug release studies were conducted in the phosphate buffer saline (PBS) at pH 7.4. The results suggest that varying the concentrations of TiO2/PANI nanoparticles could change the rate of drug release. The release mechanism was studied using several kinetic models, including the Higuchi model, the Hixson–Crowell model, and the Korsmeyer–Peppas model, to clarify the mechanism of SIM release from the composite nanofibers. The assessment of in vitro mineralization of the composite nanofibers for the growth of hydroxyapatite was performed in simulated body fluid (SBF). Field scanning electron microscopy (FE-SEM) imagery and energy-dispersive X-ray spectroscopy (EDS) analyses indicated that after soaking in SBF, a hydroxyapatite layer was formed on the surface of the nanofibrous webs. These novel composite nanofibers release simvastatin in a controlled manner with profound cell proliferation and attachment compared to that in pure PCL nanofiber, which indicates their potential for bone regeneration applications.

Highly capable and cost-effective chitosan nanocomposite films containing folic acid-functionalized layered double hydroxide and their in vitro bioactivity performance

Currently, bio-based resources and modern techniques with cost-effective routes have lots of interests in the biological process. Herein, environmentally-friendly, cost-efficient, and biologically active folic acid (FA) modified layered double hydroxide (LDH) was fabricated. Then, to characterize the effect of the FA molecule on the LDH structure, we prepared pure carbonated LDH (LDH-CO32-) as well. Increasing in the interlayer space from 0.76 nm for LDH-CO32- to 1.28 nm for FA-modified-LDH (FA-LDH) approved the accomplishment of the intercalation process. Based on thermal analysis, the retained mass of FA-LDH was lower than the pure LDH; corresponding to the influence of organic segments. Subsequently, homogeneous nanocomposite (NC) films containing FA-LDH nano-sheets and chitosan (CS) were fabricated. Although the NC films showed fragile form, their char yield was improved (maximum 19%) compared to the neat CS film. Contact angle measurement indicated an improvement in the wettability behavior and more hydrophilic property for the prepared CS NCs. In addition, we examined the bioactivity potential of these NC films through the immersing of them in simulated body fluid with pH = 7.4, and the changes of pH for this solution were recorded for 30 days. The results of field emission scanning electron microscopy, Fourier transform infrared, and energy-dispersive X-ray analyses indicated the growth of hydroxyapatite [Ca10(OH)2(PO4)6] on the surface of the fabricated compounds. Accordingly, these NC films have great potential to be used in tissue engineering technology.

Mineralization of calcium phosphate controlled by biomimetic self-assembled peptide monolayers via surface electrostatic potentials

The functions of acidic-rich domains in non-collagenous protein during biomineralization are thought to induce nucleation and control the growth of hydroxyapatite. The tripeptide Asp-Ser-Ser (DSS) repeats are the most common acidic-rich repeated unit in non-collagenous protein of dentin phosphoprotein, the functions of which have aroused extensive interests. In this study, biomimetic peptides (DSS)n (n = 2 or 3) were designed and fabricated into self-assembled monolayers (SAMs) on Au (111) surface as biomimetic organic templates to regulate hydroxyapatite (HAp) mineralization in 1.5 simulated body fluid (1.5 SBF) at 37 °C. The early mineralization processes and minerals deposited on the SAMs were characterized by X-ray diffraction, scanning electron microscope, and Fourier transform infrared spectroscopy analyses. The SAM-DSS9/DSS9G showed the highest capacity to induce HAp nucleation and growth, followed by SAM-DSS6/DSS6G, SAM-COOH, and SAM-OH. The SAM-(DSS)n had more negative zeta potentials than SAM-COOH surface, indicating that DSS repeats contributed to the biomineralization, which not only provided strong affinity with Ca2+ ions through direct electrostatic bonds, but more importantly influence surface electrostatic potentials of the assembled organic template for nucleation.