OBJECTIVE: To review the research progress and challenges of poly (L-lactic acid) (PLLA) membrane in preventing tendon adhesion. METHODS: The relevant literature at home and abroad in recent years was extensively searched, covering the mechanism of tendon adhesion formation, the adaptation challenge and balancing strategy of PLLA, the physicochemical modification of PLLA anti-adhesion membrane and its application in tendon anti-adhesion. In this paper, the research progress and modification strategies of PLLA membranes were systematically reviewed from the three dimensions of tissue adaptation, mechanical adaptation, and degradation adaptation. RESULTS: The three-dimensional adaptation of PLLA membrane is optimized by combining materials (such as hydroxyapatite, polycaprolactone), structural design (multilayer/gradient membrane), and drug loading (anti-inflammatory drug). The balance between anti-adhesion and pro-healing is achieved, the mechanical adaptation significantly improve, and degradation is achieved (targeting the degradation cycle to 2-4 weeks to cover the tendon repair period). CONCLUSION In the future, it is necessary to identify the optimal balance point of three-dimensional fitness, unify the evaluation criteria and solve the degradation side effects through the co-design of physicochemical modification and drug loading system to break through the bottleneck of clinical translation.
Tissue Adhesions/prevention & control* ; Polyesters/chemistry* ; Humans ; Biocompatible Materials/chemistry* ; Tendons/surgery* ; Membranes, Artificial ; Tendon Injuries/surgery* ; Wound Healing ; Animals ; Durapatite/chemistry*

OBJECTIVE: To explore the effect of nano-hydroxyapatite/collagen composite (nHAC) on bone graft fusion after anterior cervical discectomy and fusion (ACDF) in patients with cervical spondylosis and low bone mass. METHODS: A retrospective analysis was conducted on 47 patients with low bone mass who underwent ACDF from 2017 to 2021. They were divided into the nHAC group and the allogeneic bone group according to different bone graft materials. The nHAC group included 26 cases, with 8 males and 18 females;aged 50 to 78 years old with an average of (62.81±7.79) years old;the CT value of C₂-C₇ vertebrae was (264.16±36.33) HU. The allogeneic bone group included 21 cases, with 9 males and 12 females;aged 54 to 75 years old with an average of (65.95±6.58) years old;the CT value of C₂-C₇ vertebrae was (272.39±40.44) HU. The visual analogue scale (VAS), neck disability index (NDI), and Japanese Orthopaedic Association (JOA) spinal cord function score were compared before surgery, 1 week after surgery, and at the last follow-up to evaluate the clinical efficacy. Imaging assessment included C₂-C₇ Cobb angle, surgical segment height, intervertebral fusion, and whether the cage subsidence occurred at 1 week after surgery and the last follow-up. RESULTS: The follow-up duration ranged from 26 to 39 months with an average of (33.27±3.34) months in the nHAC group and 26 to 41 months with an average of (31.86±3.57) months in the allogeneic bone group. At 1 week after surgery and the last follow-up, the VAS, NDI scores, and JOA scores in both groups were significantly improved compared with those before surgery, with statistically significant differences (P<0.05). At 1 week after surgery, the C₂-C₇ Cobb angles in the nHAC group and the allogeneic bone group were (14.26±10.32)° and (14.28±8.20)° respectively, which were significantly different from those before surgery (P<0.05). At the last follow-up, the C₂-C₇ Cobb angles in both groups were smaller than those at 1 week after surgery, with statistically significant differences (P<0.05). At 1 week after surgery, the height of the surgical segment in the nHAC group was (31.65±2.55) mm, and that in the allogeneic bone group was (33.63±3.26) mm, which were significantly different from those before surgery (P<0.05). At the last follow-up, the height of the surgical segment in both groups decreased compared with that at 1 week after surgery, with statistically significant differences (P<0.05). At the last follow-up, 39 surgical segments were fused and 6 cages subsided in the nHAC group;40 surgical segments were fused and 7 cages subsided in the allogeneic bone group;there was no statistically significant difference between the two groups (P>0.05). Compared with the CT value of vertebrae without cage subsidence, the CT value of vertebrae with cage subsidence in both groups was significantly lower, with a statistically significant difference (P<0.05). CONCLUSION The application of nHAC in ACDF for patients with low bone mass can achieve effective fusion of the surgical segment. There is no significant difference in improving clinical efficacy, intervertebral fusion, and cage subsidence compared with the allogeneic bone group. With the extension of follow-up time, the C₂-C₇ Cobb angle decreases, the height of the surgical segment is lost, and the cage subsides in both the nHAC group and the allogeneic bone group, which may be related to low bone mass. Low bone mass may be one of the risk factors for cervical spine sequence changes, surgical segment height loss, and cage subsidence after ACDF.
Humans ; Male ; Female ; Middle Aged ; Spondylosis/physiopathology* ; Spinal Fusion/methods* ; Cervical Vertebrae/surgery* ; Aged ; Diskectomy ; Durapatite ; Retrospective Studies ; Collagen/chemistry*

OBJECTIVES: The purpose of the study was to evaluate the effect of hydroxyapatite (HA)-based desensiti-zing agents and determine their influence on the bonding performance of mild universal adhesives. METHODS: Mid-coronal dentin samples were sectioned from human third molars and prepared for a dentin-sensitive model. According to desensitizing applications, they were randomly divided into four groups for the following treatments: no desensitizing treatment (control), Biorepair toothpaste (HA-based desensitizing toothpaste) treatment, Dontodent toothpaste (HA-based desensitizing toothpaste) treatment, and HA paste treatment. Dentin tubular occlusion and occluded area ratios were evaluated by scanning electron microscopy (SEM). Furthermore, All-Bond Universal, Single Bond Universal, and Clearfil Universal Bond were applied to the desensitized dentin in self-etch mode. The wettability and surface free energy (SFE) of desensitized dentin were evaluated by contact angle measurements. Bonded specimens were sectioned into beams and tested for micro-tensile bond strength to analyze the effect of desensitizing treatment on the bond strength to dentin of universal adhesives. RESULTS: SEM revealed that the dentin tubule was occluded by HA-based desensitizing agents, and the area ratios for the occluded dentin tubules were in the following order: HA group>Biorepair group>Dontodent group (P<0.05). Contact angle analysis demonstrated that HA-based desensitizing agents had no statistically significant influence on the wettability of the universal adhesives (P>0.05). The SFE of dentin significantly increased after treatment by HA-based desensitizing agents (P<0.05). The micro-tensile bond strength test showed that HA-based desensitizing toothpastes always decreased the μTBS values (P<0.05), whereas the HA paste group presented similar bond strength to the control group (P>0.05), irrespective of universal adhesive types. CONCLUSIONS HA-based desensitizing agents can occlude the exposed dentinal tubules on sensitive dentin. When mild and ultra-mild universal adhesives were used for subsequent resin restoration, the bond strength was reduced by HA-based desensitizing toothpastes, whereas the pure HA paste had no adverse effect on bond strength.
Humans ; Dental Cements/analysis* ; Dentin/chemistry* ; Durapatite/pharmacology* ; Tensile Strength ; Toothpastes

Surface characteristics and cellular response to titanium surfaces that had been implanted with calcium and magnesium ions using plasma immersion ion implantation and deposition (PIIID) were evaluated. Three different titanium surfaces were analyzed: a resorbable blast media (RBM) surface (blasted with hydroxyapatite grit), a calcium ionimplanted surface, and a magnesium ion-implanted surface. The surface characteristics were investigated by scanning electron microscopy (SEM), surface roughness testing, X-ray diffraction (XRD), and Auger electron spectroscopy (AES). Human bone marrow derived mesenchymal stem cells were cultured on the 3 different surfaces. Initial cell attachment was evaluated by SEM, and cell proliferation was determined using MTT assay. Real-time polymerase chain reaction (PCR) was used to quantify osteoblastic gene expression (i.e., genes encoding RUNX2, type I collagen, alkaline phosphatase, and osteocalcin). Surface analysis did not reveal any changes in surface topography after ion implantation. AES revealed that magnesium ions were present in deeper layers than calcium ions. The calcium ion- and magnesium ion-implanted surfaces showed greater initial cell attachment. Investigation of cell proliferation revealed no significant difference among the groups. After 6 days of cultivation, the expression of RUNX2 was higher in the magnesium ion-implanted surface and the expression of osteocalcin was lower in the calcium ion-implanted surface. In conclusion, ion implantation using the PIIID technique changed the surface chemistry without changing the topography. Calcium ion- and magnesium ion-implanted surfaces showed greater initial cellular attachment.
Alkaline Phosphatase ; Bone Marrow* ; Calcium* ; Cell Proliferation ; Chemistry ; Collagen Type I ; Durapatite ; Gene Expression ; Humans* ; Immersion ; Ions* ; Magnesium* ; Mesenchymal Stromal Cells* ; Microscopy, Electron, Scanning ; Osteoblasts ; Osteocalcin ; Osteogenesis ; Plasma ; Real-Time Polymerase Chain Reaction ; Spectrum Analysis ; Titanium* ; X-Ray Diffraction

OBJECTIVEThis study investigated the effects of hydroxyapatite (HA)/chitosan (CS)-transforming growth factor-β1 (TGF-β1) composite coatings on titanium surfaces, as well as on the attachment and proliferation of osteoblasts.

METHODSHA/CS-TGF-β1 composite coatings were prepared on titanium surfaces by physical, chemical, and biological modifications. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), and other methods were employed to analyze the chemical composition and surface topography of the composite coatings. CCK-8 and immunofluorescence assays were used to analyze the effects of the coatings on the attachment and proliferation of osteoblasts.

RESULTSHA/CS-TGF-β1 composite coatings were successfully prepared. Their contact angle was almost zero. These composite coatings were applied in vitro, with a drug released early and a burst release effect. The growth of osteoblasts was not inhibited on it and it had obvious promoting effect on the adhesion and early proliferation of osteoblasts.

CONCLUSIONThe composite coatings significantly promote the adhesion and early proliferation of osteoblasts in vitro. This finding shows that the proposed method demonstrates a good prospective application in surface modification of titanium.

Cell Proliferation ; Chitosan ; chemistry ; Dental Bonding ; methods ; Durapatite ; chemistry ; Microscopy, Electron, Scanning ; Osteoblasts ; physiology ; Prospective Studies ; Spectroscopy, Fourier Transform Infrared ; Surface Properties ; Titanium ; chemistry ; Transforming Growth Factor beta ; chemistry ; Transforming Growth Factors ; X-Ray Diffraction

BACKGROUNDRecently, local sustained-release antibiotics systems have been developed because they can increase local foci of concentrated antibiotics without increasing the plasma concentration, and thereby effectively decrease any systemic toxicity and side effects. A vancomycin-loaded bone-like hydroxyapatite/poly-amino acid (V-BHA/PAA) bony scaffold was successfully fabricated with vancomycin-loaded poly lactic-co-glycolic acid microspheres and BHA/PAA, which was demonstrated to exhibit both porosity and perfect biodegradability. The aim of this study was to systematically evaluate the biosafety of this novel scaffold by conducting toxicity tests in vitro and in vivo.

METHODSAccording to the ISO rules for medical implant biosafety, for in vitro tests, the scaffold was incubated with L929 fibroblasts or rabbit noncoagulant blood, with simultaneous creation of positive control and negative control groups. The growth condition of L929 cells and hemolytic ratio were respectively evaluated after various incubation periods. For in vivo tests, a chronic osteomyelitis model involving the right proximal tibia of New Zealand white rabbits was established. After bacterial identification, the drug-loaded scaffold, drug-unloaded BHA/PAA, and poly (methyl methacrylate) were implanted, and a blank control group was also set up. Subsequently, the in vivo blood drug concentrations were measured, and the kidney and liver functions were evaluated.

RESULTSIn the in vitro tests, the cytotoxicity grades of V-BHA/PAA and BHA/PAA-based on the relative growth rate were all below 1. The hemolysis ratios of V-BHA/PAA and BHA/PAA were 2.27% and 1.42%, respectively, both below 5%. In the in vivo tests, the blood concentration of vancomycin after implantation of V-BHA/PAA was measured at far below its toxic concentration (60 mg/L), and the function and histomorphology of the liver and kidney were all normal.

CONCLUSIONAccording to ISO standards, the V-BHA/PAA scaffold is considered to have sufficient safety for clinical utilization.

Amino Acids ; chemistry ; Animals ; Bone and Bones ; Durapatite ; chemistry ; Microspheres ; Polymers ; chemistry ; Rabbits ; Tissue Scaffolds ; chemistry ; Vancomycin ; adverse effects

OBJECTIVETo study the influence of particle size and morphology on zinc cation adsorption by hydroxyapatite (HA) and dentifrice containing HA.

METHODSFour HAs with different particle sizes and morphologies, HA-containing dentifrice and blank dentifrice were prepared into suspensions of serial concentrations. Zinc ion solutions with an initial concentration of 10 mg/L was mixed with the suspensions and kept for 24 h for adsorption reaction. The zinc ion concentration in the supernatant was measured by inductively coupled plasma emission spectrometer and the sorption rate of zinc ion was calculated.

RESULTSHA and HA-containing dentifrice with various particle sizes and morphologies were all capable of absorbing zinc ions from simulated waste water, and the adsorption rate of HA-containing dentifrice was 3%-10% higher than that of HA. HA with a particle size of 12 µm and a spherical morphology showed the strongest adsorption ability, followed by short bar-shaped HA with a particle size of 30 µm. Both Langmuir and Freundlich equation could simulate the sorption processes of HA dentifrice, while only Langmuir equation could simulate the sorption processes of HA.

CONCLUSIONIncorporation of HA in dentifrice can enhance zinc ion adsorption capacity of the material. The particle size and morphology of HA both affect the adsorption of zinc ions, and 12-µm HA particle with a spherical morphology has the best adsorption ability.

Adsorption ; Dentifrices ; chemistry ; Durapatite ; chemistry ; Particle Size ; Solutions ; Zinc ; chemistry

OBJECTIVETo explore biomimetic mineralization of polyelectrolyte multilayer films (PEM) of gene-loaded lipopolysaccharide-amine nanopolymersomes/hyaluronic acid self assembled on titanium surface.

METHODSVia lay-by-layer self assembly technology, PEM were constructed on titanium or quartz surface using bone morphogenetic protein-2(BMP-2) plasmid-loaded lipopolysaccharide-amine nanopolymersomes(pLNP) as a polycation, and hyaluronic acid(HA) as a polyanion. The constructed PEM were defined as substrate-pLNP-(HA-pLNP)n, where a successive deposition of HA and pLNP on substrate surface was defined as one assembly cycle, and n was the cycle number. Biomimetic mineralization on surfaces of Ti-pLNP-(HA-pLNP)4(Group A, with outermost layer of pLNP), Ti-pLNP-(HA-pLNP)4.5(Group B, with outermost layer of HA), blank control(polished titanium, Ti) and alkaline-heat treated titanium(Ti-OH) were investigated. The biomimetic mineralization was analyzed by observing the topography under field-emisssion electron microscopy(FE-SEM), characterizing the surface chemical structure and components via X-ray diffractometer(XRD) and X-ray energy disperse spectroscopy(EDS).

RESULTSFor experiment groups, XRD analysis showed that the diffraction peak of hydroxyapatite appeared, and its intensity was higher than that for Ti group. FE-SEM images showed that its surface was homogeneously covered by discrete agglomerate of big particles. EDS spectra showed that the percentage of Ca and P were 77.24% and 64.23%, and these were much higher than those in Ti group.

CONCLUSIONSThe surface of Ti-pLNP-(HA-pLNP)n is favorable for in vitro biomimetic mineralization.

Amines ; chemistry ; Biomimetic Materials ; chemistry ; Bone Morphogenetic Protein 2 ; Durapatite ; chemistry ; Hyaluronic Acid ; chemistry ; Lipopolysaccharides ; Nanocomposites ; chemistry ; Plasmids ; Surface Properties ; Titanium ; chemistry

To explore the inhibitory effect of hydroxyapatite (HA) particles with different sizes on malignant melanoma A375 cells in vitro, we synthesized 4 short rod-like HA particles using TIPS. Their mean diameters were 998.0 nm (HA1), 511.0 nm (HA2), 244.0 nm (HA3), and 71.6 nm (HA4), respectively. Malignant melanoma A375 cells were co-cultured with HA particles in vitro. Results showed that HA particles smaller than 511.0 nm in mean diameter could always inhibit proliferation of A375 cells, and nanometer-HA particles (HA4) had the strongest inhibitory effect on A375 cell proliferation and the strongest inducing effect on apoptosis. HA particles were distributed in plasma of A375 cells. The ultrastructure changes of A375 cells were found most significant in nanometer-HA particles (HA4) group. We conclude that particle size is a very important influencing factor on anti-tumor effects of HA and that nanometer-HA particle has the strongest inhibitory effect on tumor cell proliferation.
Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Durapatite ; chemistry ; Humans ; Melanoma ; Nanotubes ; chemistry ; Particle Size

In order to improve the interfacial bonding strength of hydroxyapatite/polyurethane implanted material and dispersion of hydroxyapatite in the polyurethane matrix, we in the present study synthesized nano-hydroxyapatite/polyurethane composites by in situ polymerization. We then characterized and analyzed the fracture morphology, thermal stability, glass transition temperature and mechanical properties. We seeded MG63 cells on composites to evaluate the cytocompatibility of the composites. In situ polymerization could improve the interfacial bonding strength, ameliorate dispersion of hydroxyapatite in the properties of the composites. After adding 20 wt% hydroxyapatite into the polyurethane, the thermal stability was improved and the glass transition temperatures were increased. The tensile strength and maximum elongation were 6.83 MPa and 861.17%, respectively. Compared with those of pure polyurethane the tensile strength and maximum elongation increased by 236.45% and 143.30%, respectively. The composites were helpful for cell adhesion and proliferation in cultivation.
Biocompatible Materials ; chemistry ; Cell Adhesion ; Cell Line ; Durapatite ; chemistry ; Humans ; Polymerization ; Polyurethanes ; Tensile Strength ; Transition Temperature