Accuracy and feasibility of 3D-printed custom open trays for impressions of multiple implants: A self-controlled clinical trial.

STATEMENT OF PROBLEM: Three-dimensionally printed custom open trays have become a popular option in clinical implant dentistry because of advantages such as individualization, efficiency, and effectiveness. However, clinical evidence on their accuracy and feasibility is lacking. PURPOSE: The purpose of this clinical study was to evaluate the accuracy and feasibility for impressions of multiple implants by using 3D-printed custom open trays versus conventional custom open trays. MATERIAL AND METHODS: Twenty-two partially edentulous individuals needing impression making for restorations supported by multiple implants were enrolled. Two types of custom open trays were made for each participant, a 3D-printed tray (test) and a conventional tray (control). With a splinted technique, silicone definitive impressions were obtained with the 2 custom open trays and poured with Type IV dental stone. Impression accuracy (primary outcome) was evaluated by measuring linear distances and the marginal gaps between the implant replicas and verification devices on the test and control casts. Clinical tray fit, impression quality, and cast quality were rated by an independent technician through a visual analog scale (VAS). The fabrication time and cost of the 2 types of custom open trays were recorded. The feasibility of 3D-printed trays was determined from these outcomes. The paired Student t test and Wilcoxon rank-sum tests were used for statistical analysis (α=.05). RESULTS: For impression accuracy, no statistically significant difference was found between test and control groups (P>.05). In terms of clinical tray fit, impression quality, and cast quality, no statistically significant difference was found (all P>.05). Regarding fabrication time and cost, the test group (57.65 ±6.49 minutes, 0.37 ±0.07 United States dollars [USD]) exhibited superiority over the control group (101.96 ±2.92 minutes, 4.41 ±0.37 USD) (both P<.001). CONCLUSIONS: Within the limitations of this study, the 3D-printed custom open trays were clinically accurate, efficient, and cost-effective for impressions of multiple implants.

A modified implant abutment holder fabricated with fused deposition modeling to improve the transfer process for implant-supported restorations.

Ingestion or aspiration of an implant abutment can occur in patients during the process of abutment transfer for implant-supported restorations, especially in the posterior region. A technique of fabricating an abutment holder is described to prevent ingestion or aspiration by computer-aided design (CAD) and fused deposition modeling (FDM). The modified abutment holder has a serrated handle for a firm grip and a barrel-shaped fixed portion that firmly secures the abutment. The modified holder is more secure than the conventional hexagon screwdriver. Furthermore, abutment holders can be easily manufactured by using 3D printers and repeatedly used for multiple implants restoration without substitution.

Genome-wide DNA-methylation profiles in human bone marrow mesenchymal stem cells on titanium surfaces.

The characteristics of titanium (Ti) have been shown to influence dental implant fixation. Treatment of surfaces using the sandblasted, large-grit, acid-etched (SLA) method is widely used to provide effective osseointegration. However, the DNA methylation-associated mechanism by which SLA surface treatment affects osseointegration of human bone marrow mesenchymal stem cells (hBMSCs) remains elusive. Genome-wide methylation profiling of hBMSCs on SLA-treated and machined smooth Ti was performed using Illumina Infinium Methylation EPIC BeadChip at day 7 of osteogenic induction. In total, 2,846 CpG sites were differentially methylated in the SLA group compared with the machined group. Of these sites, 1,651 (covering 1,066 genes) were significantly hypermethylated and 1,195 (covering 775 genes) were significantly hypomethylated. Thirty significant enrichment pathways were observed, with Wnt signaling being the most significant. mRNA expression was identified by microarray and combined with DNA-methylation profiles. Thirty-seven genes displayed negative association between mRNA expression and DNA-methylation level, with the osteogenesis-related genes insulin-like growth factor 2 (IGF2) and carboxypeptidase X, M14 Family Member 2 (CPXM2) showing significant up-regulation and down-regulation, respectively. In summary, our results demonstrate differences between SLA-treated and machined surfaces in their effects on genome-wide DNA methylation and enrichment of osteogenic pathways in hBMSCs. We provide novel insights into genes and pathways affected by SLA treatment in hBMSCs at the molecular level.

Concentrated Growth Factor Promotes Dental Pulp Cells Proliferation and Mineralization and Facilitates Recovery of Dental Pulp Tissue.

BACKGROUND Dental pulp cells (DPCs) play vital roles in the recovery of dental pulp tissue. Concentrated growth factor (CGF) can promote proliferation and mineralization of various cells. However, the functions of CGF on DPCs and dental pulp tissue are unclear. The object of our study was to identify the roles of CGF in DPCs proliferation and mineralization in vitro and to assess the effects of CGF on direct pulp capping in vivo. MATERIAL AND METHODS We performed CCK-8 and Transwell assay to detect proliferation and migration activity of DPCs. Alizarin Red staining was performed to examine mineralized nodules. Alkaline phosphatase activity test was used to measure the mineralization capacity of DPCs. We assessed the odontogenic differentiation gene expression level by Western blot and qPCR. The effect of CGF on direct pulp capping in vivo were evaluated by radiography and histopathology. RESULTS CGF increased the number of proliferative and migratory DPCs. CGF enhanced DPCs mineralized nodules and improved the gene expression levels of DSPP, DMP-1, BSP, and ALP. CGF upregulated the protein levels of ALP, BMP2, SMAD5, Runx2, and p-Smad, and the effect could be partially reversed by Noggin. CGF promoted pulp recovery and kept its vitality in directly pulp capping. CONCLUSIONS CGF promotes DPCs proliferation and mineralization. It regulates the mineralization of DPCs via the BMP2/SMAD5/Runx2 signaling pathway. CGF can be used as the effective graft for direct pulp capping.

Gold-nanobranched-shell based drug vehicles with ultrahigh photothermal efficiency for chemo-photothermal therapy.

Development of combined chemo-photothermal nanoplatform is of great interest for enhancing antitumor efficacy. Herein, a multifunctional drug delivery system was synthesized based on gold-nanobranched coated betulinic acid liposomes (GNBS-BA-Lips) for chemo-photothermal synergistic therapy. In this system, GNBS-BA-Lips exhibited broad near-infrared (NIR) absorption, preferable photothermal response and good photostability under NIR irradiation. Importantly, the gold-nanobranched nanostructure possessed high photothermal conversion efficiency (η = 55.7%), and the temperature change (ΔT) reached 43.2 °C after laser irradiation for 5 min. Upon NIR irradiation, the nanocarriers apparently endowed higher cell uptake, resulting in an enhanced intracellular drug accumulation. Furthermore, the tumor growth inhibition ratio achieved from chemo-photothermal therapy of GNBS-BA-Lips was 86.9 ±â€¯1.1%, which was higher than that of the chemotherapy or photothermal therapy alone, showing an outstanding synergistic anticancer effect. Our data suggested that the nanoplatform should be considered as a critical platform in the development of cancer multi-mode therapies.

Development of rapid bioconversion with integrated recycle technology for ethanol production from extractive ammonia pretreated corn stover.

High enzyme loading and low productivity are two major issues impeding low cost ethanol production from lignocellulosic biomass. This work applied rapid bioconversion with integrated recycle technology (RaBIT) and extractive ammonia (EA) pretreatment for conversion of corn stover (CS) to ethanol at high solids loading. Enzymes were recycled via recycling unhydrolyzed solids. Enzymatic hydrolysis with recycled enzymes and fermentation with recycled yeast cells were studied. Both enzymatic hydrolysis time and fermentation time were shortened to 24 h. Ethanol productivity was enhanced by two times and enzyme loading was reduced by 30%. Glucan and xylan conversions reached as high as 98% with an enzyme loading of as low as 8.4 mg protein per g glucan. The overall ethanol yield was 227 g ethanol/kg EA-CS (191 g ethanol/kg untreated CS). Biotechnol. Bioeng. 2017;114: 1713-1720. © 2017 Wiley Periodicals, Inc.

Gold nanoshell-based betulinic acid liposomes for synergistic chemo-photothermal therapy.

A novel synthesis approach is first developed to fabricate a multifunctional smart nanodrug delivery system: gold nanoshell-coated betulinic acid liposomes (AuNS-BA-Lips) mediated by a glutathione. The AuNS-BA-Lips exhibited good size distribution (149.4±2.4nm), preferable photothermal conversion ability and synergistic chemo-photothermal therapy. Additionally, the absorption wavelength of AuNS-BA-Lips showed a significantly red-shifted to near infrared (NIR) region, which can strongly absorbed NIR laser and efficiently convert it into localized heat, thus providing controlled drug release and antitumor thermotherapy. Moreover, the nanocarriers excited by NIR light significantly promoted cell uptake compared to those without irradiation, resulting in an enhanced intracellular drug accumulation. Upon NIR irradiation, the AuNS-BA-Lips showed highly efficient antitumor effects on tumor-bearing mice with an inhibition rate of 83.02%, thus demonstrating a remarkable synergistic therapeutic effect of chemotherapy and thermotherapy. Therefore, this work provides new insight into developing a multifunctional antitumor drug.

Combined Near Infrared Photothermal Therapy and Chemotherapy Using Gold Nanoshells Coated Liposomes to Enhance Antitumor Effect.

Novel antitumor system based on the targeting photothermal and pH-responsive nanocarriers, gold nanoshells coated oleanolic acid liposomes mediating by chitosan (GNOLs), is designed and synthesized for the first time. The GNOLs present spherical and uniform size (172.03 nm) with zeta potential (20.7 ± 0.4 mV), which are more easily accumulated in tumor. Meanwhile, the GNOLs exhibit a slow and controlled release of oleanolic acid at pH 7.4, as well as a rapid release at pH 5.5, which is beneficial for tumor-targeting drug release. Under near infrared (NIR) irradiation, hyperthermia can be generated by activated gold nanoshells to perform photothermal therapy effect, which triggers drug release from the carriers by activating the gel to liquid crystalline phase transition of the liposomes. Moreover, the NIR assisting drug release can be easily and selectively activated locally due to the spatially and real-timely controllable property of light. The experimental results also verify that the GNOLs with NIR irradiation achieve more ideal antitumor effects than other oleanolic acid formulations in vitro and in vivo. Hence, the drug delivery system exhibits a great potential in chemo-photothermal antitumor therapy.

Gold Nanoshells: Combined Near Infrared Photothermal Therapy and Chemotherapy Using Gold Nanoshells Coated Liposomes to Enhance Antitumor Effect (Small 30/2016).

Gold nanoshell coated oleanolic acid liposomes mediating by chitosan (GNOLs), are designed and successfully synthesized for the first time by D. Gao and co-workers on page number 4103. An excellent near infrared (NIR) photothermal effect, pH-responsive drug controlled release and tumor targeting properties are demonstrated. By combining NIR photothermal therapy and chemotherapy, the smart drug delivery system exhibits a superior antitumor property in vitro and in vivo.

On-demand drug release of ICG-liposomal wedelolactone combined photothermal therapy for tumor.

In the study, a new photoresponsive nano drug delivery system was developed by encapsulating indocyanine green into liposomes (ICG-liposomal wedelolactone), which could improve the water solubility and bioavailability of wedelolactone. The hyperthermia, produced by ICG under near-infrared (NIR) light irradiation, promoted wedelolactone release rapidly from the carriers. The release amount of ICG-liposomal wedelolactone under NIR irradiation reached up to 96.74% over 8h, achieving the drug of on-demand release. Moreover, the growth of HepG2 cells was obviously inhibited by ICG-liposomal wedelolactone under NIR, and the early apoptotic rate of HepG2 cells was 33.74%. The tumor inhibition rate was 81% in the mice bearing tumor treated with the drug system. The results proved that ICG-liposomal wedelolactone, as a novel drug delivery system to co-delivery chemotherapeutic agents and photothermal agents, achieved synergetic effect of chemotherapy and photothermotherapy, which will have an enormous potential in future cancer therapy.

H2O2 is the transferrable factor mediating flow-induced dilation in human coronary arterioles.

RATIONALE: Endothelial derived hydrogen peroxide (H(2)O(2)) is a necessary component of the pathway regulating flow-mediated dilation (FMD) in human coronary arterioles (HCAs). However, H(2)O(2) has never been shown to be the endothelium-dependent transferrable hyperpolarization factor (EDHF) in response to shear stress. OBJECTIVE: We examined the hypothesis that H(2)O(2) serves as the EDHF in HCAs to shear stress. METHODS AND RESULTS: Two HCAs were cannulated in series (a donor intact vessel upstream and endothelium-denuded detector vessel downstream). Diameter changes to flow were examined in the absence and presence of polyethylene glycol catalase (PEG-CAT). The open state probability of large conductance Ca(2+)-activated K(+) (BK(Ca)) channels in smooth muscle cells downstream from the perfusate from an endothelium-intact arteriole was examined by patch clamping. In some experiments, a cyanogen bromide-activated resin column bound with CAT was used to remove H(2)O(2) from the donor vessel. When flow proceeds from donor to detector, both vessels dilate (donor:68±7%; detector: 45±11%). With flow in the opposite direction, only the donor vessel dilates. PEG-CAT contacting only the detector vessel blocked FMD in that vessel (6±4%) but not in donor vessel (61±13%). Paxilline inhibited dilation of endothelium-denuded HCAs to H(2)O(2). Effluent from donor vessels elicited K(+) channel opening in an iberiotoxin- or PEG-CAT-sensitive fashion in cell-attached patches but had little effect on channel opening on inside-out patches. Vasodilation of detector vessels was diminished when exposed to effluent from CAT-column. CONCLUSIONS: Flow induced endothelial production of H(2)O(2), which acts as the transferrable EDHF activating BK(Ca) channels on the smooth muscle cells.

[Study on the extraction process and macroporous resin for purification of Timosaponin B II].

OBJECTIVE: To optimize the extraction process and macroporous resin for purification of Timosaponin B II from Anemarrhena asphodeloides. METHODS: Orthogonal design L9 (34) was employed to optimize the circumfluence extraction conditions by taking the extraction yield of Timosaponin B II as index. The absorption-desorption characteristics of eight kinds of macroporous resins were evaluated, then the best resin was chosen to optimize the purification process conditions. RESULTS: The optimum extraction conditions were as follows: the herb was extracted for 2 times (2 hours each time) with 8.5-fold 50% ethanol at the first time and 6-fold 50% ethanol at the second time. HPD100 resin showed a good property for the absorption-desorption of Timosaponin B II. The optimum technological conditions of HPD100 resin were as follows:the solution concentration was 0.23 mg/mL, the amount of saturated adsorption at 4/5 body volumn (BV) resin, the HPD100 resin was washed with 3 BV water and 6 BV 20% ethanol solution to remove the impurity, then the Timosaponin B II was desorbed by 5 BV ethanol solution. The purity of Timosaponin B II was about 50%. CONCLUSION: The optimized extraction process and purification is stable, efficient and suitable for industrial production.

[Effects of chain length of polyacrylic acid (PAA) on proteins adsorption of polystyrene-polyacrylic acid (PS-PAA) spherical polyelectrolyte brushes].

We studied the interaction between proteins and polystyrene-polyacrylic acid (PS-PAA) spherical polyelectrolyte brushes with different polyacrylic acid (PAA) chain lengths, including the physical adsorption and chemical adsorption in PBS buffer. Results showed that the amount of bovine serum albumin (BSA) physically adsorbed on PS-PAA spherical polyelectrolyte brushes decreased to a minimum of 33 microg/mg whereas the amount of streptavidin (SA) chemically adsorbed increased with the increase of chain length and carboxyl quantity. The biotin binding capacity of streptavidin chemically adsorbed on PS-PAA spherical polyelectrolyte brushes was roughly evaluated via enzyme competitive inhibition.

Optimization of Cellulase Immobilization with Sodium Alginate-Polyethylene for Enhancement of Enzymatic Hydrolysis of Microcrystalline Cellulose Using Response Surface Methodology.

A novel method of immobilizing cellulase on sodium alginate (SA)-polyethylene glycol (PEG) enabled the cellulase to be used repeatedly. The matrix of the immobilized cellulase was detected and characterized using Fourier transform infrared spectroscopy and scanning electron microscopy. In comparison with SA-immobilized cellulase, the relative enzyme activity and immobilization rate increased by 25% and 18%, respectively. The application range of the immobilized enzyme in terms of temperature and pH was larger than that of the free enzyme, and its thermal stability increased. The immobilized enzyme was used in enzymatic hydrolysis, in which MCC was used as the substrate. The optimal conditions for enzymatic hydrolysis were as follows: the dosage of SA-PEG-immobilized cellulase was 3.55 g/g total solids of the substrate, the concentration of the substrate was 13.16%, and the pH was 5.11. In comparison with the yield of reducing sugars in the first round of hydrolysis of MCC by SA-immobilized cellulase, the yield in the hydrolysis of MCC by SA-PEG-immobilized cellulase increased by 133%. After five cycles of repeated use, the total yield of reducing sugars when MCC was hydrolyzed by SA-PEG-immobilized cellulase was similar to that achieved with free cellulase. In comparison with the free enzyme, the highest yield when the immobilized enzyme was used was 22.68%. Therefore, the immobilized cellulase exhibited high performance in enzymatic hydrolysis.

Micro-arc oxidation-assisted sol-gel preparation of calcium metaphosphate coatings on magnesium alloys for bone repair.

Calcium phosphate coating is an attractive surface modification strategy for magnesium alloys, since it can increase their corrosion resistance and endow them with osteogenic function simultaneously. Herein, a calcium metaphosphate (CMP) coating was fabricated on magnesium alloy by using sol-gel approach assisted with micro-arc oxidation pre-treatment. Scanning electron microscopy showed that the micro-pores and cracks in micro-arc oxidation inner layer generated during the pre-treatment process were sealed by the grainy sol-gel outer layer. Energy dispersive spectrometry and X-ray diffraction results demonstrated the identity of the coating as CMP. The cross-cut test showed that the adhesion of CMP coating was strong. Applying bare magnesium alloy substrate as a control, the CMP coating surface was rougher and more hydrophilic. The potentiodynamic polarization test demonstrated that the corrosion resistance was significantly improved by using CMP coating. Hydrogen evolution in immersion test further confirmed that the degradation rate was decelerated within 14 days. Moreover, CMP coating facilitated the adhesion speed, spreading area, and focal adhesion formation of bone marrow stem cells. The number of cells in the active proliferating state and proliferated cells present on the CMP coating also increased. Additionally, CMP coating upregulated alkaline phosphatase activity and osteogenic gene expression in cells. In summary, the micro-arc oxidation assisted sol-gel CMP coatings increased the corrosion resistance and promoted the interfacial cell behavior for magnesium alloy implants, which might inform the further development of surface modifications on magnesium alloys for bone related applications.

Knockdown of microRNA-584 promotes dental pulp stem cells proliferation by targeting TAZ.

Proliferation of dental pulp stem cells (DPSCs) is crucial in tooth development and damage repairing, also includes its therapy application for tissue engineering. MicroRNAs (miRNAs) are key players in biological processes of DPSCs, and transcriptional co-activator with PDZ-binding motif (TAZ) also plays important roles in cell proliferation and differentiation, however, the roles of miR-584 and TAZ in DPSCs are not known. We found up-regulated miR-584 expression and down-regulated TAZ expression levels in aging dental pulp tissue compare to those in young dental pulp tissue. In proliferating DPSCs we demonstrated the decreased miR-584 expression and increased TAZ expression. miR-584 mimics suppressed DPSCs proliferation and migration, and significantly reduced TAZ production, whereas miR-584 inhibition exerted the converse effects. Knocking down of the TAZ in DPSCs had a similar effect as overexpression of miR-584. Furthermore, luciferase reporter assay demonstrated that miR-584 could directly bind to the TAZ mRNA 3'UTR to repress its translation. Overexpression of TAZ can partly rescue miR-584 mimic-mediated the inhibition of proliferation. Additionally, miR-584 inhibited cell proliferation and downregulated expression of cell cycle proteins by AKT signaling pathway. Together, we identified that miR-584 may be a key regulator in the proliferation of DPSCs by regulating TAZ expression via AKT signaling pathway. It would be a promising biomarker and therapeutic target for pulp disease.

Accuracy of multi-implant impressions using 3D-printing custom trays and splinting versus conventional techniques for complete arches.

PURPOSE: To assess the three-dimensional (3D) accuracy of multi-implant impressions for complete arches obtained using 3D printing technology, and to determine the clinical feasibility of this approach by comparing the results obtained with those obtained with conventional impression techniques. MATERIALS AND METHODS: A maxillary model matrix with four implant analogs was used to fabricate 10 stone reference models (control) to simulate edentulous patients. Ten 3D-printed impressions were made using polylactic acid custom open trays with component splinting (3D-printed group). To make 10 conventional impressions of the reference models, the poly(methyl methacrylate) open trays with splinting technique was used (conventional group). Impressions were poured with a type IV dental stone, which had been digitalized utilizing a high-resolution laboratory scanner after connecting the polymer scan bodies. Standard tessellation language (STL) datasets from the two groups of stone models were superimposed with the corresponding reference models. The interimplant distances and interimplant angulations for each implant pair were measured for the reference models and for the two test groups' definitive models, to assess 3D deviations. In addition, the mechanical properties of polylactic acid and poly(methyl methacrylate) tray materials were compared by means of three-point loading and tensile bond tests. The Student t test was used to compare the differences in implant position and mechanical properties between the two groups, while implant angulations were analyzed with Wilcoxon's rank-sum test, at P = .05. RESULTS: There was less implant-position deviation for the 3D-printed group (mean ± SD: 56.37 ± 12.52 µm) than for the conventional group (71.94 ± 18.86 µm) (P = .014). No significant differences were found in angular deviation between the two groups (P > .05). Flexural strength results suggested that polylactic acid (112.7 ± 1.62 MPa) was stronger than poly(methyl methacrylate) (104.0 ± 2.17 MPa; P < .0001). The tensile bond strength of polylactic acid (0.07 ± 0.005 MPa) was higher than that of poly(methyl methacrylate) (0.03 ± 0.004 MPa; P < .0001). CONCLUSION: The 3D-printing multi-implant impression technique could be an alternative to conventional impression techniques for complete arches.

A chemo-photothermal synergetic antitumor drug delivery system: Gold nanoshell coated wedelolactone liposome.

In this study, an antitumor drug delivery system, gold nanoshell coated wedelolactone liposomes (AuNS-Wed-Lip), were designed and synthesized. In the drug delivery system, wedelolactone liposome and gold-nanoshell were linked by l-cysteine, which had been shown an effective nanocarrier for antitumor drug delivery, on-demand drug release, and phototherapy under near-infrared (NIR) light irradiation. It was capable of absorbing 780-850 nm NIR light and converting light energy to heat rapidly. The hyperthermia promoted wedelolactone release rapidly from the systems. The release amount of AuNS-Wed-Lip under NIR irradiation reached up to 97.34% over 8 h, achieving the on-demand drug release. Moreover, a high inhibition rate up to 95.73% for 143B tumor cells by AuNS-Wed-Lip upon laser irradiation at 808 nm was observed. The excellent inhibition efficacy was also displayed in vivo antitumor study with S180 tumor-bearing mice. The results demonstrated that AuNS-Wed-Lip, as an antitumor drug delivery system, achieved chemo-photothermal synergetic effect, which has great potential in cancer therapy.

Uptake, distribution, clearance, and toxicity of iron oxide nanoparticles with different sizes and coatings.

Iron oxide nanoparticles (IONPs) have been increasingly used in biomedical applications, but the comprehensive understanding of their interactions with biological systems is relatively limited. In this study, we systematically investigated the in vitro cell uptake, cytotoxicity, in vivo distribution, clearance and toxicity of commercially available and well-characterized IONPs with different sizes and coatings. Polyethylenimine (PEI)-coated IONPs exhibited significantly higher uptake than PEGylated ones in both macrophages and cancer cells, and caused severe cytotoxicity through multiple mechanisms such as ROS production and apoptosis. 10 nm PEGylated IONPs showed higher cellular uptake than 30 nm ones, and were slightly cytotoxic only at high concentrations. Interestingly, PEGylated IONPs but not PEI-coated IONPs were able to induce autophagy, which may play a protective role against the cytotoxicity of IONPs. Biodistribution studies demonstrated that all the IONPs tended to distribute in the liver and spleen, and the biodegradation and clearance of PEGylated IONPs in these tissues were relatively slow (>2 weeks). Among them, 10 nm PEGylated IONPs achieved the highest tumor uptake. No obvious toxicity was found for PEGylated IONPs in BALB/c mice, whereas PEI-coated IONPs exhibited dose-dependent lethal toxicity. Therefore, it is crucial to consider the size and coating properties of IONPs in their applications.

Enhancing anaerobic digestion performance and degradation of lignocellulosic components of rice straw by combined biological and chemical pretreatment.

In order to determine eco-friendly pretreatment method, the combination of different pretreatment reagents such as: CaO, ammonia solution (AS), liquid fraction of digestate (LFD), CaO-AS and CaO-LFD were used in this study. The features of physico-chemical structures and anaerobic digestion (AD) performance of rice straw were investigated using different combined biological and chemical pretreatment methods. The results showed that CaO-LFD bio-chemical pretreatment achieved the best effect among different pretreatment conditions. The removal rate of lignocellulosic components from CaO-LFD pretreated rice straw was 20.73% higher than that of the control sample. The ether and ester bonds between lignin and hemicellulose were ruptured during pretreatment. Moreover, the methane yield from CaO-LFD pretreated rice straw was 274.65 mL gVS-1, which was 57.56% more than the control. Compared with the untreated rice straw, T80 decreased by 42.86%. CaO-LFD combined pretreatment has advantages as both biological and chemical pretreatment, which complement each other to improve the degradation of the rice straw. Meantime, AD performance was improved and excellent economic viability was achieved. Therefore, this study provides sustainable insight for exploring efficient pretreatment strategy to stabilize and enhance AD performance for further application.