A novel ZIF-8@IL-MXene/poly (N-isopropylacrylamide) nanocomposite hydrogel toward multifunctional adsorption.

Phenols, dyes, and metal ions present in industrial wastewater can adversely affect the environment and leach biological carcinogens. Given that the current research focuses only on the removal of one or two of those categories. Herein, this work reports a novel ZIF-8@IL-MXene/Poly(N-isopropylacrylamide) (NIPAM) nanocomposite hydrogel that can efficiently and conveniently absorb and separate multiple pollutants from industrial wastewater. Ionic liquid (IL) was grafted onto MXene surfaces using a one-step method, and then incorporated into NIPAM monomer solutions to obtain the IL-MXene/PNIPAM composite hydrogel via in-situ polymerization. ZIF-8@IL-MXene/PNIPAM nanocomposite hydrogels were obtained by in-situ growth of ZIF-8 on the pore walls of composite hydrogels. As-prepared nanocomposite hydrogel showed excellent mechanical properties and can withstand ten repeated compressions without any damage, the specific surface area increased by 100 times, and the maximum adsorption capacities for p-nitrophenol (4-NP), crystal violet (CV), and copper ion (Cu2+) were 198.40, 325.03, and 285.65 mg g-1, respectively, at room temperature. The VPTTs of all hydrogels ranged from 33 to 35 °C, so the desorption process can be achieved in deionized water at 35-40 °C, and its adsorption capacities after five adsorption-desorption cycles decreased to 79%, 91%, and 29% for 4-NP, CV, and Cu2+, respectively. The adsorption data fitting results follow pseudo-second-order kinetics and Freundlich models, which is based on multiple interactions between the functional groups contained in hydrogels and adsorbent molecules. The hydrogel is the first to realize the high-efficiency adsorption of phenols, dyes and metal ions in industrial wastewater simultaneously, and the preparation process of hydrogels is environmentally friendly. Also, giving hydrogel multifunctional adsorption is beneficial to promote the development of multifunctional adsorption materials.

Antibacterial and Biofilm-Eradicating Activities of pH-Responsive Vesicles against Pseudomonas aeruginosa.

The formation of biofilms by a microcolony of bacteria is a significant burden on the healthcare industry due to difficulty eradicating it. In this study, pH-responsive vesicles capable of releasing apramycin (APR), a model aminoglycoside antibiotic, in response to the low pH typical of establishedPseudomonas aeruginosa biofilms resulted in improved eradication of existing biofilms in comparison to the free drug. The amphiphilic polymeric vesicle (PV) comprised of block polymer poly (ethylene glycol)-block-poly 2-(dimethylamino) ethyl methacrylate (mPEG-b-pDEAEMA) averaged 128 nm. The drug encapsulation content of APR in PV/APR was confirmed to be 28.2%, and the drug encapsulation efficiency was confirmed to be 51.2%. At pH 5.5, PV/APR released >90% APR after 24 h compared to <20% at pH 7.4. At pH 5.5, protonation of the pDEAEMA block results in a zeta potential of +23 mV compared to a neutral zeta potential of +2.2 mV at pH 7.4. Confocal microscopy, flow cytometry, and scanning electron microscopy reveal that the positively charged vesicles can compromise the integrity of the planktonic bacterial membrane in a pH-dependent manner. In addition, PV/APR is able to diffuse into mature biofilms to release APR in the acidic milieu of biofilm bacteria, and PV/APR was more efficient at eliminating preexisting biofilms compared to free APR at 128 and 256 µg/mL. This study reveals that dynamic charge density in response to pH can lead to differential levels of interactions with the biofilm and bacterial membrane. This effectively results in enhanced antibacterial and antibiofilm properties against both planktonic and difficult-to-treat biofilm bacteria at concentrations significantly lower than those of the free drug. Overall, this pH-responsive vesicle could be especially promising for treating biofilm-associated infectious diseases.

Effects of Polyethyelene Glycol-Desferrioxamine:Gallium Conjugates on Pseudomonas aeruginosa Outer Membrane Permeability and Vancomycin Potentiation.

Pseudomonas aeruginosa exhibits a broad spectrum of intrinsic antibiotic resistance because of the limited permeability of its outer membrane. Given this situation, molecules that could make Gram-negative bacteria more permeable and more susceptible to large-scaffold Gram-positive antibiotics may be advantageous. Herein, we evaluate the antimicrobial activity of a series of targeted poly(ethylene glycol)-desferrioxamine/gallium (PEG-DG) conjugates that can improve the sensitivity of P. aeruginosa to the glycopeptide vancomycin (VAN). We observed that single-ended mPEG-DG and double-ended PEG-DG2 conjugates characterized by PEG MW ≥2000 synergistically enhanced the sensitivity of VAN against P. aeruginosa reference strains PAO1 and ATCC 27853 and three clinically isolated carbapenem-resistant strains, but not Escherichia coli strain ATCC 25922. Although the exact mechanism of this phenomenon is currently under investigation, PEG-DG conjugates enhanced nitrocefin (NCF), hexidium iodide (HI), and VAN permeability only when PEG and DG were directly conjugated. The two most important physicochemical factors contributing to the synergistic activity observed with VAN relate to (1) the final concentration of DG ligands conjugated to the polymer and (2) the polymer length, wherein MW ≥2000 yielded a similar fractional inhibitory concentration.

Evaluation of salivary biomarkers for the diagnosis of periodontitis.

BACKGROUND: Salivary interleukin (IL)-1ß, matrix metalloproteinase (MMP)-8, pyridinoline cross-linked carboxyterminal telopeptide of type I collagen (ICTP) and Porphyromonas gingivalis (Pg) are related to periodontitis. This study aimed to investigate the diagnostic potential of these biomarkers and to build a prediction panel for diagnosing periodontal disease. METHODS: A total of 80 participants were enrolled in a cross-sectional study and divided into healthy (n = 25), gingivitis (n = 24), and periodontitis (n = 31) groups based on their periodontal exam results. A full mouth periodontal examination was performed and unstimulated saliva was collected. Salivary IL-1ß, MMP-8, ICTP, and Pg were assessed using enzyme-linked immunosorbent assay (ELISA) and quantitative real time PCR (qPCR). Their potentials for diagnosing periodontal disease were analyzed and combined prediction panels of periodontal disease were evaluated. RESULTS: As a single marker, IL-1ß showed the best diagnostic value of the four markers evaluated and exhibited an area under the curve (AUC) value of 0.88 with 90% sensitivity and 76% specificity for discriminating periodontitis subjects from healthy subjects, an AUC value of 0.80 with 83% sensitivity and 76% specificity for discriminating gingivitis subjects from healthy subjects and an AUC value of 0.66 with 68% sensitivity and 64% specificity for differentiating periodontitis subjects from gingivitis subjects. The combination of IL-1ß, ICTP, and Pg exhibited the highest efficacy for discriminating periodontitis subjects from healthy subjects (AUC = 0.94) and gingivitis subjects (AUC = 0.77). The combination of IL-1ß and MMP-8 exhibited the best ability to discriminate gingivitis from healthy subjects (AUC = 0.84). CONCLUSIONS: Salivary IL-1ß, MMP-8, ICTP, and Pg showed significant effectiveness for diagnosing periodontal disease. The combination of IL-1ß, ICTP, and Pg can be used to discriminate periodontitis subjects from healthy subjects and gingivitis subjects, and the combination of IL-1ß and MMP-8 can be used to discriminate gingivitis subjects from healthy subjects.

Evaluation of a photocrosslinkable hydroxyethyl chitosan hydrogel as a potential drug release system for glaucoma surgery.

Hydroxyethyl chitosan (HECTS) is a critical derivative of chitosan that has been widely used as biomedical materials due to great water-solubility and excellent biocompatibility. Here, photosensitive hydroxyethyl chitosan was synthesized by introducing azide group on NH2 of HECTS (HECTS-AZ), afterwards FTIR and 1H NMR spectra were detected to confirm the formation of HECTS-AZ. The solution of HECTS-AZ can achieve a sol-gel transition through UV irradiation for 30 s. The evaluation of biocompability and biodegradability in vivo was conducted in rats, visual and pathological examinations exhibited the HECTS-AZ has excellent biocompability and degradation time of the hydrogel is more than 14 weeks. Furthermore, HECTS-AZ hydrogel as an ocular drug delivery system loading heparin was prepared to implant under sclera of rabbit after glaucoma filtration surgery (GFS). The experimental results demonstrated the heparin loaded hydrogel can effectively maintain filtration bleb and lowing intraocular pressure (IOP) after GFS for prolonged time. Besides, obvious inflammatory reactions and side effects have not been observed in ocular during the experimental period. In conclusion, the HECTS-AZ hydrogel is a potential drug delivery device for the treatment of glaucoma and other ocular diseases.

Polymeric supra-amphiphiles based on terminal group electrostatic interactions: fabrication of micelles with modifiable surfaces.

On the basis of terminal group electrostatic interactions (TGEI), a supra-amphiphile is formed between a homopolymer of polylactic acid with carboxyl group at one end (PLA-COOH) and hepta-6-hydrazyl-ß-cyclodextrin (HH-CD). The amphiphile can self-assemble into a micellar structure in aqueous solution. The outer surface of the micelle, which is composed of cyclodextrins, can be further modified via host-guest interactions. Considering the biocompatibility of the building blocks, the application of the micelles in a nanocarrier of anticancer drugs is further explored.

The accuracy of cone-beam computed tomography in assessing maxillary molar furcation involvement.

AIM: The aim of this study was to investigate the accuracy of cone-beam computed tomography (CBCT) in assessing maxillary molar furcation involvement (FI). MATERIALS AND METHODS: Fifteen patients with generalized chronic periodontitis after initial therapy were recruited. CBCT was performed in maxillary molars with probing pocket depths of ≥6 mm and advanced FI, and CBCT images were analysed. Furcation surgery was performed in 20 maxillary molars. Lastly, intra-surgical FI assessments were compared with CBCT-based data. RESULTS: Intra-surgical findings confirmed 82.4% of the CBCT data, with a weighted kappa of 0.917. The agreement between both assessments was the highest in buccal furcation entrances, followed by distopalatal and mesiopalatal furcation entrances. Of the four parameters tested of detailed root anatomy and furcation morphology, the mean length of the root trunk and the width of the furcation entrance revealed by CBCT were consistent with their respective intra-surgical values (p > 0.05). Horizontal bone loss and vertical bone loss were underestimated by CBCT relative to their respective intra-surgical classifications (p ≤ 0.05). CONCLUSIONS: Cone-beam computed tomography images demonstrate a high accuracy in assessing the loss of periodontal tissue of the FI and root morphologies in maxillary molars.

[Effect of regenerative therapy for the furcation involvements of mandibular molars evaluated by cone-beam computed tomography].

OBJECTIVE: To evaluate the effect of regenerative therapy for the treatment of furcation involvements of mandibular molars with cone-beam computed tomography (CBCT). METHODS: In the study, 38 furcation involvements of mandibular molars were included and randomly divided into two groups. The experimental group accepted guided tissue regeneration and bone graft therapy, and the control group only flap surgery. The clinical examination and CBCT examination were performed at baseline and 1 year post-surgery. RESULTS: The clinical and CBCT data of both groups were not statistically different at baseline (P>0.05). At the end of 1 year post-surgery, except gingival recession, the clinical parameters of both groups were significantly improved (P<0.001). The vertical and horizontal attachment gains of the experimental group were (3.20 ± 1.82) mm and (2.05 ± 1.27) mm, respectively, and significantly higher than the changes of the control group (P<0.001). And at the end of 1 year post-surgery, the experimental group showed significantly higher bone gain at the vertical and horizontal directions compared with those of the control group: (2.82 ± 0.97) mm and (2.24 ± 0.92) mm, respectively (P<0.001). CONCLUSION: With the limitation of this study, the effect of guided tissue regeneration surgery and bone graft therapy for the treatment of furcation involvements of mandibular molars is significantly better than that of the flap surgery. CBCT can reflect the horizontal and vertical bone changes of furcation area, which is more comprehensive than traditional periapicals.

Synthesis and evaluation of an amphiphilic deferoxamine:gallium-conjugated cationic random copolymer against a murine wound healing infection model of Pseudomonas aeruginosa.

Multidrug resistant (MDR) Gram-negative bacteria are an urgent global health threat. We report on the design and evaluation of a xenosiderophore-conjugated cationic random copolymer (pGQ-DG) which exhibits selective antibacterial activity against Pseudomonas aeruginosa (P. aeruginosa) by targeting select outer membrane (OM) receptors for scavenging xenosiderophores such as deferoxamine (DFO), while possessing favorable cytocompatibility and exhibiting low hemolysis, to enhance and safely damage the bacterial OM. pGQ-DG demonstrated synergistic properties in combination with vancomycin (VAN) when evaluated in vitro against P. aeruginosa. In addition, pGQ-DG plus VAN cleared the P. aeruginosa infection and efficiently accelerated healing in a murine wound healing model as effectively as colistin, suggesting that this strategy could serve as an alternative to colistin against MDR bacteria. STATEMENT OF SIGNIFICANCE: P. aeruginosa exhibits intrinsic antibiotic resistance due to limited permeability of its outer membrane (OM). A triple combination antipseudomonal approach was investigated by 1) selectively targeting P. aeruginosa through the complex DFO:gallium, 2) disrupting the OM through a cationic random copolymer, and 3) enhancing bacteria sensitivity to VAN as a result of the OM disruption. Synthesis and characterization of the lead polymer pGQ-DG, mechanism of action, antimicrobial activity, and biocompatibility were investigated in vitro and in vivo. Overall pGQ-DG plus VAN cleared the P. aeruginosa infection and accelerated wound healing in mice as effectively as colistin, suggesting that this strategy could serve as an alternative to colistin against multidrug resistant P. aeruginosa.

Rat sciatic nerve regeneration across a 10-mm defect bridged by a chitin/CM-chitosan artificial nerve graft.

Chitosan as a natural bioactive biopolymer has been commonly employed in guidance conduit for repairing peripheral nerve injury, due to its excellent properties of low toxicity, antibacterial properties, high biocompatibility and biodegradability. In this study, chitin and CM-chitosan were prepared from pharmaceutical grade chitosan. Moreover, a novel composite chitosan-based nerve graft comprising microporous chitin-based conduit and internal CM-chitosan fiber was constructed and applied to bridge sciatic nerve across a 10-mm defect in SD rats. The chitin/CM-chitosan artificial nerve graft could promote the proliferation of rat Schwann cells (RSC96) with good cell biocompatibility. After implantation, the artificial nerve graft showed slow degradation. No apparent toxicity was observed, and tissue inflammation was very slight after implantation, indicating favorable bio-safety of the nerve graft. Furthermore, the chitin/CM-chitosan artificial nerve graft could effectively promote restoration of damaged neurons with similar effect compared to the autograft. In conclusion, the composite biodegradable chitin/CM-chitosan nerve grafts possessed favorable biocompatibility and good potential in repairing peripheral nervous injury.

Terpyridine-Micelles for Inhibiting Bacterial Biofilm Development.

Iron plays a critical role in bacterial infections and is especially critical for supporting biofilm formation. Until recently, Fe(III) was assumed to be the most relevant form of iron to chelate in therapeutic antimicrobial strategies due to its natural abundance under normal oxygen and physiologic conditions. Recent clinical data obtained from cystic fibrosis (CF) patients found that there is actually quite an abundance of Fe(II) present in sputum and that there exists a significant relationship between sputum Fe(II) concentration and severity of the disease. A biocompatible mixed micelle formed from the self-assembly of poly(lactic- co-glycolic acid)- block-methoxy poly(ethylene glycol) (PLGA- b-mPEG) and poly(lactic- co-glycolic acid)- block-poly(terpyridine)5 [PLGA- b-p(Tpy)5] polymers was prepared to chelate Fe(II) (Tpy-micelle). Tpy-micelles showed high selectivity for Fe(II) over Fe(III), decreased biofilm mass more effectively under anaerobic conditions at >4 µM Tpy-micelles, reduced bacteria growth in biofilms by >99.9% at 128 µM Tpy-micelles, effectively penetrated throughout a 1-day old biofilm, and inhibited biofilm development in a concentration-dependent manner. This study reveals that Fe(II) chelating Tpy-micelles are a promising addition to Fe(III) chelating strategies to inhibit biofilm formation in CF lung infections.

ROS-triggered degradable iron-chelating nanogels: Safely improving iron elimination in vivo.

Iron-mediated generation of highly toxic Reactive Oxygen Species (ROS) plays a major role in the process leading to iron overload-related diseases. The long-term subcutaneous administration of Deferoxamine (DFO) is currently clinically-approved to improve patient symptoms and survival. However, non-specific toxicity and short circulation times of the drug in humans often leads to poor patient compliance. Herein, thioketal-based ROS-responsive polymeric nanogels containing DFO moieties (rNG-DFO) were designed to chelate iron and to degrade under oxidative stimuli into fragments <10 nm to enhance excretion of iron-bound chelates. Serum ferritin levels and iron concentrations in major organs of IO mice decreased following treatment with rNG-DFO, and fecal elimination of iron-bound chelates increased compared to free DFO. Furthermore, rNG-DFO decreased iron mediated oxidative stress levels in vitro and reduced iron-mediated inflammation in the liver of IO mice. The study confirms that ROS-responsive nanogels may serve as a promising alternative to DFO for safer and more efficient iron chelation therapy.

Desferrioxamine:gallium-pluronic micelles increase outer membrane permeability and potentiate antibiotic activity against Pseudomonas aeruginosa.

The outer membrane of Pseudomonas aeruginosa functions primarily as a permeability barrier and imparts a broad spectrum of intrinsic antibiotic resistance. Herein, we describe the synthesis, characterization, and antimicrobial evaluation of a targeted polymeric micelle that specifically permeabilizes the outer membrane and potentiates antibiotic activity against P. aeruginosa.

Biomechanical properties and healing effects of chitin patch in a rat full-thickness abdominal wall defect model.

Hernia repair is usually accompanied with the implantation of a synthetic mesh, which frequently results in a foreign body response and serious complications. In the present study, a novel biodegradable chitin-based hernia patch was prepared and characterized. Biomechanical properties and biodegradability of the chitin patch were quantified in vitro and in vivo. In repair of the rat abdominal wall full-thickness defect model, the chitin patch induced more abundant new blood vessels with milder tissue inflammation and fibrosis compared with polypropylene mesh. Chitin patch effectively inhibited excessive secretion of inflammation-associated cytokines (IL-6 and TNF-α) (p < 0.01) and significantly increased the secretion of healing-related cytokines (FGF1 and TGF-ß1) (p < 0.01). Accompanied by biodegradation of the chitin patch, intra-abdominal adhesions caused by the chitin patch decreased significantly, and the tensile strength of the repaired site could meet the biomechanical requirements of human abdominal wall. After the one-year observation period, the defected abdominal wall returned to the appropriate thickness with no obvious complication or hernia occurrence. In a conclusion, the newly designed chitin patch showed good biomechanical properties and satisfactory healing effects on the full-thickness defect of abdominal wall, which makes it promising candidate for clinical hernia treatment. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1349-1357, 2018.

Multifunctional Polymeric Micelles for Combining Chelation and Detection of Iron in Living Cells.

Multifunctional self-assembled micelles composed of Pluronics F127 polymer chains are developed and investigated for chelation and selective detection of iron(III) in vitro and in iron-overloaded cells. Tetraphenylethene (TPE) is encapsulated into the micelle core and the iron chelate drug deferoxamine (DFO) is conjugated to micelles to generate a fluorescence quenching detection system termed DFO-TFM for short, where T stands for TPE, F for F127, and M for micelle. The key to the successful formation of this fluorescence quenching system is due to the near-ideal overlap between the absorption spectrum of the DFO:iron(III) complex and fluorescence spectrum of TPE. DFO-TFM can retain the iron-chelation properties of DFO and exhibits negligible cytotoxicity compared to free DFO. Furthermore, this fluorescence "turn-off" system can be utilized to detect the presence of iron and to monitor the chelation process in an iron overload cell model. This study serves as an effective proof-of-concept model for designing future in vivo systems capable of combining the features of iron chelation with iron detection and efforts toward the development of such detection systems are currently underway.

Study of a new biodegradable hernia patch to repair abdominal wall defect in rats.

A novel biodegradable chitin hernia patch was prepared by acetylation of chitosan fabric in our study. Physicochemical properties, cell compatibility and biodegradability of the chitin patch were quantified. Histopathological study of the functional experiment showed that this newly designed hernia patch promoted collagen deposition and neovascularization by significantly promoting the secretion of FGF1 and TGF-ß1 in the early postoperative (P<0.01). Chitin patch caused less inflammation by inhibiting excessive expression of IL-6 and TNF-α when compared to the polypropylene mesh (P<0.01). Acceptable fibrosis was consistent with the results of immunohistochemistry studies. The density of FGF1 and TGF-ß1 positive cells in the chitin patch group at 7 d was reduced to a lower level at 15 d (P<0.01). With regeneration of the defect abdominal wall, chitin patch degraded gradually, avoiding foreign body response and chronic complications. Our studies demonstrated that the newly designed chitin patch showed good promise for the hernia treatment.

Human Pluripotent Stem Cell-Derived Cardiac Tissue-like Constructs for Repairing the Infarcted Myocardium.

High-purity cardiomyocytes (CMs) derived from human induced pluripotent stem cells (hiPSCs) are promising for drug development and myocardial regeneration. However, most hiPSC-derived CMs morphologically and functionally resemble immature rather than adult CMs, which could hamper their application. Here, we obtained high-quality cardiac tissue-like constructs (CTLCs) by cultivating hiPSC-CMs on low-thickness aligned nanofibers made of biodegradable poly(D,L-lactic-co-glycolic acid) polymer. We show that multilayered and elongated CMs could be organized at high density along aligned nanofibers in a simple one-step seeding process, resulting in upregulated cardiac biomarkers and enhanced cardiac functions. When used for drug assessment, CTLCs were much more robust than the 2D conventional control. We also demonstrated the potential of CTLCs for modeling engraftments in vitro and treating myocardial infarction in vivo. Thus, we established a handy framework for cardiac tissue engineering, which holds high potential for pharmaceutical and clinical applications.

Effect of platelet-rich plasma in the treatment of periodontal intrabony defects in humans.

BACKGROUND: Platelet-rich plasma (PRP) is a kind of natural source of autologous growth factors, and has been used successfully in medical community. However, the effect of PRP in periodontal regeneration is not clear yet. This study was designed to evaluate the effectiveness of PRP as an adjunct to bovine porous bone mineral (BPBM) graft in the treatment of human intrabony defects. METHODS: Seventeen intrabony defects in 10 periodontitis patients were randomly treated either with PRP and BPBM (test group, n = 9) or with BPBM alone (control group, n = 8). Clinical parameters were evaluated including changes in probing depth, relative attachment level (measured by Florida Probe and a stent), and bone probing level between baseline and 1 year postoperatively. Standardized periapical radiographs of each defect were taken at baseline, 2 weeks, and 1 year postoperatively, and analyzed by digital subtraction radiography (DSR). RESULTS: Both treatment modalities resulted in significant attachment gain, reduction of probing depth, and bone probing level at 1-year post-surgery compared to baseline. The test group exhibited statistically significant improvement compared to the control sites in probing depth reduction: (4.78 +/- 0.95) mm versus (3.48 +/- 0.41) mm (P < 0.01); clinical attachment gain: (4.52 +/- 1.14) mm versus (2.85 +/- 0.80) mm (P < 0.01); bone probing reduction: (4.56 +/- 1.04) mm versus (2.88 +/- 0.79) mm (P < 0.01); and defect bone fill: (73.41 +/- 14.78)% versus (47.32 +/- 11.47)% (P < 0.01). DSR analysis of baseline and 1 year postoperatively also showed greater radiographic gains in alveolar bone mass in the test group than in the control group: gray increase (580 +/- 50) grays versus (220 +/- 32) grays (P = 0.0001); area with increased gray were (5.21 +/- 1.25) mm(2) versus (3.02 +/- 1.22) mm(2) (P = 0.0001). CONCLUSIONS: The treatment with a combination of PRP and BPBM led to a significantly favorable clinical improvement in periodontal intrabony defects compared to using BPBM alone. Further studies are necessary to assess the long-term effectiveness of PRP, and a larger sample size is needed.

Multifunctional self-assembled polymeric nanoprobes for FRET-based ratiometric detection of mitochondrial H2O2 in living cells.

A ratiometric, multifunctional nanoprobe was prepared consisting of a self-assembled polymeric micelle as the carrier, tetraphenylethene (TPE) as the donor, fluorescent boronate as the H2O2-responsive acceptor, and triphenylphosphonium as a mitochondria-targeted moiety. The assembled nanoparticles could detect both exogenous and endogenous mitochondrial H2O2 changes in living cells.

Photodynamic effects on human periodontal-related cells in vitro.

BACKGROUND: Photodynamic therapy (PDT) may be especially effective in combination with conventional periodontal therapy by its antimicrobial activities, but PDT may also exhibit other mechanisms that promote the healing of periodontal tissue. Therefore, the purpose of the present study was to evaluate the photodynamic effect of PDT on human periodontal ligament cells (hPDLCs) and human gingival fibroblasts (hFBs) in vitro and other possible mechanisms to promote periodontal healing. METHODS: The proliferation of hPDLCs and hFBs was assessed by MTT assay. Cell attachment on cementum slices of hPDLCs and hFBs was evaluated by MTT assay. Type I collagen synthesis of hPDLCs and hFBs was analyzed using enzyme linked immunosorbent assay. The alkaline phosphatase (ALP) activity in hPDLCs was measured by p-nitrophenyl phosphate substrate reactions. RESULTS: PDT treatment induced constant time-dependent growth of hPDLCs and hFBs at 24h, 72h and 6 days (P<0.05). PDT treatment also promoted time-dependent hPDLCs and hFBs attachment on the cementum slices at 24h, 72h and 6 days compared to the controlled cells (P<0.05). Type I collagen synthesis of hPDLCs and hFBs was markedly stimulated by PDT in a time-dependent manner (P<0.05). Likewise, a significant increase in the specific ALP activity in hPDLCs was observed (P<0.05). CONCLUSIONS: The findings of this study indicate that PDT exhibited no cytotoxicity to hPDLCs or hFBs. Instead, it stimulated proliferation, attachment and collagen synthesis of hPDLCs and hFBs and ALP activity of hPDLCs. These effects might signal similar PDT activity on periodontal-related cells, and expanding the scope of its potential therapeutic utilization is very appealing.