Silk fibroin/methacrylated gelatine/hydroxyapatite biomimetic nanofibrous membranes for guided bone regeneration.

By mimicking in vivo bionic microenvironment and promoting osteogenic differentiation, the hybrid organic-inorganic nanofibrous membranes provide promising potential for guided bone regeneration (GBR) in the treatment of clinical bone defects. To develop a degradable and osteogenic membrane for GBR by combining the natural biomacromolecule silk fibroin (SF) and gelatine with the bioactive nano hydroxyapatite (nHA), the anhydride-modified gelatine-nano hydroxyapatite (GelMA-nHA) composites were synthesized in situ and introduced into silk fibroin to prepare nanofibrous membranes with different ratios using electrospinning and photocrosslinking. The nanofibrous membranes, particularly those with a mass ratio of 7:2:1, were found to exhibit satisfactory elongation at break up to 110 %, maintain the nanofibrous structure for up to 28 days, and rapidly form bone-like apatite within 3 days, thus offering advantages when it comes to guided bone regeneration. In vitro cell results showed that the SF/GelMA/nHA membranes had excellent biocompatibility and enhanced osteogenic differentiation of hBMSCs. In vivo studies revealed that the hybrid composite membranes can improve bone regeneration of critical-sized calvarial defects in rat model. Therefore, the novel hybrid nanofibrous membrane is proposed to be a alternative candidate for creating a bionic microenvironment that promotes bone regeneration, indicating their potential application to bone injury treatment.

[Four-year follow-up study of onlay and occlusal veneer restorations on posterior teeth].

OBJECTIVE: To investigate the survival rate and clinical failure reasons of onlay and occlusal veneer restorations retrospectively, and to put forward valuable suggestions for the selection of clinical indications. METHODS: A total of 102 patients and 124 teeth treated by one of the authors from 2016 to 2019 were subjected to CAD/CAM lithium silicate reinforced glass-ceramic onlay or veneer restorations of premolars and molars, including 43 teeth with pulp vitality, 81 endodontic treated teeth, and occlusal thickness of restoration was 1.5 mm. After four years of restoration, retrospective surveys were conducted to record the survival rate of restorations, the causes of restoration failure, and patient satisfaction rates, and the survival rate of restorations between vital teeth and endodontic treated teeth and among restored teeth was statistically analyzed by Chi-square test. RESULTS: The survival rates of restorations on vital teeth and endodontic treated teeth were 95.5% and 90.0%, respectively, the average survival rate was 90.2%. The survival rates of vital teeth were higher than those of endodontic treated teeth without statistical difference. There was also no statistically significant difference among the tooth locations. The causes of failure included the cracking of the restoration, the loss of the restoration, the fracture of the abutment teeth, secondary caries below the adjacent contact point, and food impaction caused by the loosening of the adjacent contact point. The overall patient satisfaction rate was 91.5%. CONCLUSION: The 4-year survival rate of glass-ceramic onlays and occlusal veneers is lower than that of the full crown restoration, and there are more complications than that of the single-crown restorations. The design of the restoration should be carefully selected based on the vitality of the abutment tooth and the remaining amount of tooth tissue. When there is too little tooth structure left, a post and crown should be selected for restoration. Adequate strength and thickness of the restoration should be ensured to prevent food impaction. Due to the small amount of abutment tooth preparation, it has the advantages of less stimulation of the pulp and periodontal tissue, and can be recommended as a trial restoration.

Development of magnetic poly(L-lactic Acid) nanofibrous microspheres for transporting and delivering targeted cells.

To avoid infection and other risks caused by large open-surgery incisions using scaffold transplants, it is very important to study injectable microcarrier-loaded cells for targeted therapy and tissue regeneration. In this study, on the one hand, to simulate the hierarchical structure of the extracellular matrix and carry cells, poly(L-lactic acid) (PLLA) nanofibrous microspheres (large microspheres) were initially fabricated as cell carriers. On the other hand, to precisely deliver cells through a magnetic field and promote stem cell differentiation, drug-loaded mesoporous Fe3O4@SiO2 microspheres (small microspheres) were prepared and coated on the surface PLLA nanofibrous microspheres. The coating conditions were systematically studied and optimized. The results showed that planetary-satellite-like cell carriers were successfully prepared and the carriers were capable of freely translocating under the influence of a magnetic field. It has been demonstrated in vitro experiments that the carriers are biocompatible and are capable of acting as drug carriers. Specifically, they were able to load and release cells in response to magnetic fields. In vivo experiments indicated that the carriers could successfully load and release GFP-labelled cells in nude mice. The study presented in this paper provides a versatile and promising platform for the cell-based therapy in tissue engineering and regenerative medicine.

Anti-Inflammatory and Mineralization Effects of an ASP/PLGA-ASP/ACP/PLLA-PLGA Composite Membrane as a Dental Pulp Capping Agent.

Dental pulp is essential for the development and long-term preservation of teeth. Dental trauma and caries often lead to pulp inflammation. Vital pulp therapy using dental pulp-capping materials is an approach to preserving the vitality of injured dental pulp. Most pulp-capping materials used in clinics have good biocompatibility to promote mineralization, but their anti-inflammatory effect is weak. Therefore, the failure rate will increase when dental pulp inflammation is severe. The present study developed an amorphous calcium phosphate/poly (L-lactic acid)-poly (lactic-co-glycolic acid) membrane compounded with aspirin (hereafter known as ASP/PLGA-ASP/ACP/PLLA-PLGA). The composite membrane, used as a pulp-capping material, effectively achieved the rapid release of high concentrations of the anti-inflammatory drug aspirin during the early stages as well as the long-term release of low concentrations of aspirin and calcium/phosphorus ions during the later stages, which could repair inflamed dental pulp and promote mineralization. Meanwhile, the composite membrane promoted the proliferation of inflamed dental pulp stem cells, downregulated the expression of inflammatory markers, upregulated the expression of mineralization-related markers, and induced the formation of stronger reparative dentin in the rat pulpitis model. These findings indicate that this material may be suitable for use as a pulp-capping material in clinical applications.

Distribution of mature and newly regenerated nerve fibres after tooth extraction and dental implant placement: An immunohistological study.

BACKGROUND: The time-dependent peri-implant innervation needs to be elucidated in detail. OBJECTIVES: To examine the distribution of mature and newly regenerated nerves around the implant with immunofluorescence during 28-day follow-up after implantation. METHODS: 35 male Sprague-Dawley rats were grouped into non-operated (n = 5), extraction (n = 5) and implant (n = 25) groups. For rats in the extraction and implant groups, three right maxillary molars were extracted. One month later, a titanium implant was placed into the healed alveolar ridge in the implant group. The implant group was further divided into 5 subgroups according to day 1, 3, 7, 14 or 28 after implantation, on which day serial histological sections were prepared for immunohistochemistry. On day 28, the serial sections were also prepared in the non-operated and extraction groups. Soluble protein-100 and growth-associated protein-43 were used to immunolabel mature and newly regenerated nerve fibres, respectively. RESULTS: In the peri-implant soft tissues, the number of both mature and newly regenerated nerves showed an increasing trend in 28 days. In the bone tissues, the number of mature or newly regenerated nerves in both areas at less than 100 µm and 100-200 µm from the implant surface on day 28 grew significantly compared with that on day 1 or 3. In addition, the closest distance from mature nerves to the implant surface decreased evidently. CONCLUSION: The number of peri-implant nerves increased in 28 days since implantation. The innervation in the soft tissue took place faster than in the bone tissue. The mature nerves in the bone tissue approached the implant gradually.

Microbiological and clinical evaluation of ultrasonic debridement with/without erythritol air polishing during supportive periodontal therapy in arches with full-arch fixed implant-supported prostheses: protocol for a randomised controlled trial.

INTRODUCTION: Implant-supported prostheses are often successfully used in edentulous patients. However, the incidences of peri-implant mucositis and peri-implantitis increase over time. The accumulation of pathogenic bacteria adjacent to prostheses can induce peri-implant disease. Plaque removal is recommended to prevent and manage peri-implant diseases. The purpose of this study is to compare the plaque removal efficacy of ultrasonic debridement with/without erythritol air-polishing powder around implants and bridges in patients with full-arch fixed implant-supported prostheses as well as the effects of these two methods on the rates of peri-implant mucositis and peri-implantitis, and the submucosal microbiota composition over 5 years in patients undergoing supportive periodontal therapy. METHODS AND ANALYSIS: We plan to enrol 10 edentulous (maxilla and/or mandible) patients seeking full-arch fixed implant-supported prostheses. The study will use a split-mouth model in which contralateral quadrants are randomly assigned to two groups. Group 1: one contralateral quadrant of full-arch fixed implant-supported prostheses will undergo ultrasonic debridement combined with erythritol air-polishing powder. Group 2: a separate contralateral quadrant of full-arch fixed implant-supported prostheses will undergo ultrasonic debridement. The 5-year trial will involve a total of 10 re-examinations per participant. The mucosal conditions around the implants will be recorded at 6-month intervals after restoration. Peri-implant submucosal plaque will be collected at each re-examination, and the bacterial flora will be analysed by 16s ribosomal RNA gene sequencing. X-ray examinations will be conducted at 12-month intervals to evaluate the marginal bone level around implants. ETHICS AND DISSEMINATION: This prospective single-centre, randomised controlled trial (PKUSSIRB-202054045) has been approved by the Ethics Committee of Stomatology School and Hospital of Peking University. Data will be registered with the International Clinical Trials Registry Platform. Additionally, we will disseminate the results via publication in scientific journals. TRIAL REGISTRATION NUMBER: ChiCTR-2000032431.

Multifunctional hierarchical nanohybrids perform triple antitumor theranostics in a cascaded manner for effective tumor treatment.

Gene therapy based on transfection of RNAs/DNAs offers tremendous promise for tumor treatment. However, the relatively weak therapeutic efficiency of current genetic nanohybrids in vivo has limited the application of this strategy. Herein, we fabricated multifunctional core-shell-corona nanohybrids by combining cascaded theranostics for enhanced gene therapy. The nanohybrids consist of polydopamine-modified Fe3O4 nanoparticles as core, anti-miRNA-21 oligonucleotides (anti-miRNA) strands as shell, and doxorubicin (DOX)-conjugated DNA-8pb (DOX-DNA-8bp) as corona. The polydopamine/Fe3O4 core not only serves as an active agent for local photothermal therapy under NIR irradiation, but it also provides magnetic targeting to tumor tissue for accurate treatment, which could enhance the therapeutic effect and reduce the undesired side effects to healthy tissues. The DOX-DNA-8bp corona was grafted on the anti-miRNA shell through base pairing, which could be replaced by overexpressed miRNA-21 in tumor cells due to the strong interaction between miRNA-21 and anti-miRNA, resulting in tumor-specific gene therapy through tumorigenic miRNA-21 consumption and tumor selective chemotherapy through miRNA-21-triggered DOX-DNA-8bp release in tumor cells. Moreover, the intelligent controlled release system can gradually stop the release of DOX to prevent side effects caused by drug overdose, once sufficient damage of tumor cells has occurred, due to the downregulation of miRNA-21. The results of both in vitro and in vivo analyses showed that the nanohybrids combining cascaded chemo-photo-gene therapy could effectively inhibit tumor growth, promote the survival of tumor-bearing mice, and show no visible adverse effects on these mice, resulting in a promising nanoplatform for tumor treatment. STATEMENT OF SIGNIFICANCE: Gene therapy based on transfection of RNAs/DNAs offers tremendous promise for cancer treatment. However, the relatively weak therapeutic efficiency of current genetic nanovectors in vivo that results in insufficient tumor targeting and easy decomposition/elimination of RNAs/DNAs during therapy has limited its application. Although some approaches have combined photothermal agents or antitumor drugs with RNA/DNA nanocarriers to achieve better treatment, the spatiotemporal differences in photothermal therapy, chemotherapy, and gene therapy using current nanohybrids may hinder their synergistic effect. In the present study, we fabricated multifunctional core-shell-corona nanohybrids (Fe3O4@PDA@anti-miRNA/DNA) to simultaneously perform on-demand photothermal therapy, miR-21-triggered chemotherapy, and miR-21-dependent gene therapy at the same location, which can achieve an efficient synergistic effect for precise and effective tumor treatment.

Improving the quality of preclinical simulation training for dental students using a new digital real-time evaluation system.

BACKGROUND: With the rapid development of technology, traditional dental education has undergone a transition with the active incorporation of digital technology into curricula. DCARER is a recently developed digital real-time evaluation system for the digital assessment of student preclinical simulation practice performance. The system provides supplementary feedback on process analysis in addition to an objective final result. This study evaluated the grading validity of the DCARER system and its effect on dental preclinical practice skills training. METHODS: Seventy-three residents of Grade 2018, all of whom had completed their 3-year term residencies in standardised and systematic training, were recruited into this study to examine the system's grading validity. All performed crown preparations with the adoption of the DCARER system, which generated both process and final scores. Three experts gave their own grade anonymously according to the final work. The differences between the digital system and the expert scores were analysed. In addition, 60 dental students in Grade 4 and 10 dental faculty members were randomly divided into traditional and digital groups. The students in the traditional group prepared the tooth with the guidance of supervisors, whilst the digital group used the DCARER system. After the class, the students' tooth preparations were scored by the same three experts in a blinded manner. The students and faculty members completed two different sets of questionnaires to evaluate the effects of teaching, acceptance, satisfaction, and evaluation accuracy of the digital system and the traditional method. RESULTS: The grading validity assessment showed no significant difference between the tooth preparation scores given by the DCARER system and the experts (P> .05). The unique process scores given by the DCARER system were weakly correlated with the final scores given by both the digital system and the experts. The main characteristics of the 60 students and 10 faculty members were homogeneous at baseline (P> .05). The tooth preparations of the traditional group scored significantly lower than those of the digital group (P < .01). More students in the digital group (93.3%) believed the judgement to be objective than in the traditional group (73.3%). All students guided by the DCARER system (100%) and 80% of students taught in a traditional manner felt that the assessment reinforced the learning process. Faculty members reported that use of the digital system did not significantly increase their workload and reinforced the learning process for the internship. CONCLUSION: The results presented here indicate the validity of grading using the digital real-time evaluation system. Students and faculty could benefit from application of the system in tooth preparation practice, which may provide effective clinical interaction training for dental education.

Biomimetic Membranes of Methacrylated Gelatin/Nanohydroxyapatite/Poly(l-Lactic Acid) for Enhanced Bone Regeneration.

Nanofibrous poly(l-lactic acid) (PLLA) membrane-simulated extracellular matrices (ECMs) can be used in the biomedical field. However, the hydrophobic nature and poor osteoinductive property of PLLA limit its application in guided bone regeneration (GBR). In this work, a methacrylated gelatin/nano-HA (GelMA/nHA) complex was first synthesized in situ and then introduced into PLLA to fabricate biomimetic GelMA/nHA/PLLA membranes, mimicking the nanofibrous architecture and composition of ECMs by electrospinning and photocrosslinking. Compared to PLLA and GelMA/PLLA membranes, the novel GelMA/nHA/PLLA membranes demonstrated better tensile, hydrophilic, water sorption, and degradation properties. An in vitro biological evaluation indicated that the membranes promoted human bone marrow-derived mesenchymal stem cell (hBMSC) proliferation, adhesion, and osteogenic differentiation. Critical-sized defects in rat models were used to evaluate the bone regeneration performances of the three kinds of membranes in vivo, and the GelMA/nHA/PLLA membranes demonstrated excellent osteogenic regeneration potential. Therefore, GelMA/nHA/PLLA membranes have wide application prospects in bioengineering applications such as GBR treatment.

Comparison of peri-implant submucosal microbiota in arches with zirconia or titanium implant-supported fixed complete dental prostheses: a study protocol for a randomized controlled trial.

BACKGROUND: The success rate of implant-supported prostheses for edentulous patients is relatively high. However, the incidence of biological complications, especially peri-implant mucositis and peri-implantitis, increases yearly after the placement of prostheses. The accumulation of pathogenic bacteria adjacent to a prosthesis is the main cause of biological complications. Titanium, one of the classical materials for implant-supported prostheses, performs well in terms of biocompatibility and ease of maintenance, but is still susceptible to biofilm formation. Zirconia, which has emerged as an appealing substitute, not only has comparable properties, but presents different surface properties that influence the adherence of oral bacteria. However, evidence of a direct effect on oral flora is limited. Therefore, the aim of the present study was to assess the effects of material properties on biofilm formation and composition. METHODS: The proposed study is designed as a 5-year randomized controlled trial. We plan to enroll 44 edentulous (mandible) patients seeking full-arch, fixed, implant-supported prostheses. The participants will be randomly allocated to one of two groups: group 1, in which the participants will receive zirconia frameworks with ceramic veneering, or group 2, in which the participants will receive titanium frameworks with acrylic resin veneering. Ten follow-up examinations will be completed by the end of this 5-year trial. Mucosal conditions around the implants will be recorded every 6 months after restoration. Peri-implant submucosal plaque will be collected at each reexamination, and bacteria flora analysis will be performed with 16S rRNA gene sequencing technology in order to compare differences in microbial diversity between groups. One week before each visit, periodontal maintenance will be arranged. Each participant will receive an X-ray examination every 12 months as a key index to evaluate the marginal bone level around the implants. DISCUSSION: The current study aims to explore the oral microbiology of patients following dental restoration with zirconia ceramic frameworks or titanium frameworks. The features of the microbiota and the mucosal condition around the two different materials will be evaluated and compared to determine whether zirconia is an appropriate material for fixed implant-supported prostheses for edentulous patients. TRIAL REGISTRATION: International Clinical Trials Registry Platform (ICTRP) ChiCTR2000029470. Registered on 2 February 2020. http://www.chictr.org.cn/searchproj.aspx?

Strontium-substituted biphasic calcium phosphate microspheres promoted degradation performance and enhanced bone regeneration.

Biphasic calcium phosphate (BCP) ceramics are the subject of much attention for use as bone replacement material. However, it remains a challenge to promote the degradation and osteoinductivity performances of BCP ceramics. In this work, novel BCP ceramic microspheres with good degradation and excellent osteoinductivity were prepared through high-content strontium (Sr) doping. The in vitro results indicated that the Sr10-BCP, Sr40-BCP, and Sr80-BCP microspheres all had their HA crystals partially transformed to the beta tricalcium phosphate phase following high-temperature sintering because of Ca-deficient HA formed by the partial substitution of Ca ions by Sr ions. In addition, the degradation rate was increased with the doping of increasing amounts of Sr. All prepared microspheres enhanced human bone marrow-derived mesenchymal stem cells attachment and proliferation. Specifically, among these modified microspheres, the Sr40-BCP microspheres showed the highest osteogenic potential. Furthermore, Sr40-BCP and HA microspheres were implanted in a calvarial defect model of rat to evaluate the in vivo bone augmentation ability. The results indicated that Sr40-BCP microspheres degraded more completely and significantly promoted new bone regeneration compared with HA microspheres. In conclusion, Sr40-BCP microspheres have excellent potential for degradation and bone regeneration and are promising osteogenic materials.

Adaptive in vivo device for theranostics of inflammation: Real-time monitoring of interferon-γ and aspirin.

Cytokines mediate and control immune and inflammatory responses. Complex interactions exist among cytokines, inflammation, and the innate and adaptive immune responses in maintaining homeostasis, health, and well-being. On-demand, local delivery of anti-inflammatory drugs to target tissues provides an approach for more effective drug dosing while reducing the adverse effects of systemic drug delivery. This work demonstrates a proof-of-concept theranostic approach for inflammation based on analyte-kissing induced signaling, whereby a drug (in this report, aspirin) can be released upon the detection of a target level of a proinflammatory cytokine (i.e., interferon-γ (IFN-γ)) in real time. The structure-switching aptamer-based biosensor described here is capable of quantitatively and dynamically detecting IFN-γ both in vitro and in vivo with a sensitivity of 10 pg mL-1. Moreover, the released aspirin triggered by the immunoregulatory cytokine IFN-γ is able to inhibit inflammation in a rat model, and the release of aspirin can be quantitatively controlled. The data reported here provide a new and promising strategy for the in vivo detection of proinflammatory cytokines and the subsequent therapeutic delivery of anti-inflammatory molecules. This universal theranostic platform is expected to have great potential for patient-specific personalized medicine. STATEMENT OF SIGNIFICANCE: We developed an adaptive in vivo sensing device whereby a drug, aspirin, can be released upon the detection of a proinflammatory cytokine, interferon-γ (IFN-γ), in real time with a sensitivity of 10 pg mL-1. Moreover, the aspirin triggered by IFN-γ depressed inflammation in the rat model and was delivered indirectly through blood and cerebrospinal fluid or directly to the inflammation tissue or organ without adverse gastrointestinal effects observed in the liver and kidney. We envision that, for the first time, patients with chronic inflammatory disease can receive the right intervention and treatment at the right time. Additionally, this technology may empower patients to monitor their personalized health and disease management program, allowing real-time diagnostics, disease monitoring, and precise and effective treatments.

Injectable colloidal hydrogel with mesoporous silica nanoparticles for sustained co-release of microRNA-222 and aspirin to achieve innervated bone regeneration in rat mandibular defects.

Nerve fibers and vessels play important roles in bone formation, and inadequate innervation in the bone defect area can delay the regeneration process. However, there are few studies aiming to promote innervation to engineer bone formation. Here, we report the development of an injectable thermoresponsive mesoporous silica nanoparticle (MSN)-embedded core-shell structured poly(ethylene glycol)-b-poly(lactic-co-glycolic acid)-b-poly(N-isopropylacrylamide) (PEG-PLGA-PNIPAM) hydrogel for localized and long-term co-delivery of microRNA-222 and aspirin (ASP) (miR222/MSN/ASP hydrogel). ASP was found to stimulate bone formation as previously reported, and miR222 induced human bone mesenchymal stem cell differentiation into neural-like cells through Wnt/ß-catenin/Nemo-like kinase signaling. In a rat mandibular bone defect, injection of the co-delivered MSN hydrogel resulted in neurogenesis and enhanced bone formation, indicating that the present injectable miR222- and ASP-co-delivering colloidal hydrogel is a promising material for innervated bone tissue engineering.

Pore size directs bone marrow stromal cell fate and tissue regeneration in nanofibrous macroporous scaffolds by mediating vascularization.

In the U.S., 30% of adults suffer joint pain, most commonly in the knee, which severely limits mobility and is often attributed to injury of cartilage and underlying bone in the joint. Current treatment methods such as microfracture result in less resilient fibrocartilage with eventual failure; autografting can cause donor site morbidity and poor integration. To overcome drawbacks in treatment, tissue engineers can design cell-instructive biomimetic scaffolds using biocompatible materials as alternate therapies for osteochondral defects. Nanofibrous poly (l-lactic acid) (PLLA) scaffolds of uniform, spherical, interconnected and well-defined pore sizes that are fabricated using a thermally-induced phase separation and sugar porogen template method create an extracellular matrix-like environment which facilitates cell adhesion and proliferation. Herein we report that chondrogenesis and endochondral ossification of rabbit and human bone marrow stromal cells (BMSCs) can be controlled by scaffold pore architecture, particularly pore size. Small-pore scaffolds support enhanced chondrogenic differentiation in vitro and cartilage formation in vivo compared to large-pore scaffolds. Endochondral ossification is prevented in scaffolds with very small pore sizes; pore interconnectivity is critical to promote capillary ingrowth for mature bone formation. These results provide a novel strategy to control tissue regenerative processes by tunable architecture of macroporous nanofibrous scaffolds. STATEMENT OF SIGNIFICANCE: Progress in understanding the relationship between cell fate and architectural features of tissue engineering scaffolds is critical for engineering physiologically functional tissues. Sugar porogen template scaffolds have uniform, spherical, highly interconnected macropores. Tunable pore-size guides the fate of bone marrow stromal cells (BMSCs) towards chondrogenesis and endochondral ossification, and is a critical design parameter to mediate neotissue vascularization. Preventing vascularization favors a chondrogenic cell fate while allowing vascularization results in endochondral ossification and mineralized bone formation. These results provide a novel strategy to control tissue regenerative processes by tunable architecture of macroporous nanofibrous scaffolds.

Nanofibrous Spongy Microspheres To Distinctly Release miRNA and Growth Factors To Enrich Regulatory T Cells and Rescue Periodontal Bone Loss.

In addition to T cells' roles in immune response and autoimmune diseases, certain types of T cells, called regulatory T cells (Tregs), play important roles in microenvironment modulation for resolution and tissue regeneration. However, there are currently few options available other than introducing more Tregs or immunosuppressive drugs to locally enrich Tregs. Herein, poly(l-lactic acid) (PLLA) nanofibrous spongy microspheres (NF-SMS), PLLA/polyethylene glycol (PEG) co-functionalized mesoporous silica nanoparticles (MSN), and poly(lactic acid- co-glycolic acid) microspheres (PLGA MS) are integrated into one multibiologic delivery vehicle for in situ Treg manipulation, where the MSNs and PLGA MS were utilized to distinctly release IL-2/TGF-ß and miR-10a to locally recruit T cells and stimulate their differentiation into Tregs, while PLLA NF-SMS serve as an injectable scaffold for the adhesion and proliferation of these Tregs. In a mouse model of periodontitis, the injectable and biomolecule-delivering PLLA NF-SMS lead to Treg enrichment, expansion, and Treg-mediated immune therapy against bone loss. This system can potentially be utilized in a wide variety of other immune and regenerative therapies.

Multiple-Responsive Mesoporous Silica Nanoparticles for Highly Accurate Drugs Delivery to Tumor Cells.

A core-shell nanocarrier with triple layers, where each layer is sensitive to one specific physiological stimulus, has been fabricated for highly accurate cancer therapy. The nanocarrier consists of mesoporous silica nanoparticles (core structure for drug loading), fluorescein isothiocyanate-labeled hyaluronan (FITC-HA, first shell for imaging with enzymatic response), disulfide bond-embedded silica (SiO2, second layer with glutathione response), and switchable zwitterionic surface (third layer with pH response). The nanocarrier decorated with zwitterionic surface is able to offer long blood circulation time due to the weak nonspecific protein absorption. After these nanocarriers were gradually gathered around tumor cells through enhanced permeability and retention effect, the zwitterionic surface could switch to positive charge in low-pH environment, which was in favor of cellular uptake due to the strengthened positive nanocarrier-negative cellular membrane interaction. Once internalized into tumor cells, the high concentration of glutathione in cytoplasm could cleave disulfide bonds to remove the SiO2 shell and the HA layer would be exposed, which would be further degraded by hyaluronidase to trigger payload release. The fluorescent spectrum and images reveal that both glutathione and hyaluronidase are required for the release of preloaded drugs from these nanocarriers. By employing the multiple response, our nanocarriers could achieve effective antibiofouling ability while maintaining enhanced cellular internalization and targeted drug delivery, resulting in preferred cancer cell cytotoxicity, which is much higher than that of free doxorubicin. The in vitro data exhibited that our nanocarriers may provide an effective strategy for accurate cancer treatment.

Redox-Responsive Supramolecular Micelles for Targeted Imaging and Drug Delivery to Tumor.

The tumor-selective drug delivery system based on supramolecular micelles that were self-assembled by amphiphilic ß-cyclodextrins (ß-CD) with redox-responsiveness and fluorescence have been developed. The amphiphilic ß-CD were formed by anthraquinone (AQ) and cyclodextrins with disulfide bond in between. The disulfide bond is in charge of the responsiveness, while the AQ moiety serves as fluorescent probe. The tumor targeting was introduced by the host-guest inclusion complex between ß-CD and folate (FA), due to the known folate-receptor mediated endocytosis. The responsive disintegration of this ß-CD-AQ-FA micelles and coinstantaneous drug releases happened with cleavage of disulfide bond following tumor targeting and cell endocytosis, which was triggered by massive glutathione in the cytoplasm of tumor cells. The highly selective particle uptake by tumor cells and subsequent efficient drug delivery to these cells, which were directly demonstrated by fluorescence microscopy, resulted in an over twofold efficacy against tumor cells compared with normal cells, as well as higher tumor cytotoxicity than that caused by free drugs. These results indicate that these ß-CD-AQ-FA micelles, with performance of selective drug delivery, responsive drug release, effective drug tracking and tumor labeling, could be a promising platform for better therapeutic effects in cancer treatment.

Stepwise co-delivery of an enzyme and prodrug based on a multi-responsive nanoplatform for accurate tumor therapy.

Tumors have characteristic physiochemical conditions different from normal tissue, which makes therapy combining chemotherapeutic drugs and tumor microenvironment-responsive nanocarriers a promising route for cancer treatment. Here, we introduce a concept of integrating catalytic nanomedicine and selective chemotherapy for accurate therapy of early stage tumors by co-delivery of enzymes and prodrugs into tumor sites through a multi-responsive nanoplatform. The nanoplatform consists of a polyester-hyaluronic acid-doxorubicin (PE-HA1000k-DOX) prodrug as the corona, physiologically biodegradable silica containing disulfide bonds as the shell and hyaluronidase (absent in early stage tumors) as the core. This nanoplatform is able to quickly enter tumor cells through CD44-HA affinity. Then, the esterase and glutathione rich in tumor cells would respectively degrade the polyester and silica to release HA-DOX and hyaluronidase in a stepwise manner. Finally, highly toxic dissociative DOX is produced through decomposition of the resulting HA-DOX, catalyzed by hyaluronidase, for the apoptosis and death of the tumor cells. The properties of tumor-targeting uptake, tumor microenvironment responsiveness, efficient co-delivery of the enzyme and prodrug, and intracellular enzymatic reaction induced cytotoxicity resulted in a four-fold efficacy against tumor cells over normal cells, indicating that our nanoplatform is a promising material able to achieve both selectivity and efficiency concurrently for tumor therapeutics.

Sustained delivery of calcium and orthophosphate ions from amorphous calcium phosphate and poly(L-lactic acid)-based electrospinning nanofibrous scaffold.

The purpose of this study is to investigate electrospinning poly(L-lactic acid) (PLLA) nanofibrous scaffold with different contents of amorphous calcium phosphate (ACP), which is suitable for using in bone regeneration through sustained release of calcium and orthophosphate ions. Three groups of nanofibrous scaffolds, ACP-free PLLA, ACP-5 wt%/PLLA and ACP-10 wt%/PLLA, are developed and characterized by scanning electron microscopy and gel permeation chromatography. Calcium and phosphate colorimetric assay kits are used to test ions released from scaffold during hydrolytic degradation. The results show ACP-5 wt%/PLLA and ACP-10 wt%/PLLA scaffolds have relatively high degradation rates than ACP-free PLLA group. The bioactivity evaluation further reveals that ACP-5 wt%/PLLA scaffold presents more biocompatible feature with pre-osteoblast cells and significant osteogenesis ability of calvarial bone defect. Due to the facile preparation method, sustained calcium and orthophosphate release behavior, and excellent osteogenesis capacity, the presented ACP/PLLA nanofibrous scaffold has potential applications in bone tissue engineering.

Dual responsive hydrogels based on functionalized mesoporous silica nanoparticles as an injectable platform for tumor therapy and tissue regeneration.

To achieve effective tumor therapy and regenerate new tissue from defects formed by tumor atrophy, a dual responsive hydrogel integrating the stepwise delivery of anti-tumor drugs/growth factors and pH/thermo induced structural transformation is developed, based on polymer (poly N-isopropylacrylamide (PNIPAM) and polyacrylic acid (PAA)) functionalized mesoporous silica nanoparticles (MSNs). Due to the thermally responsive tangle between PNIPAM chains and the pH triggered hydrogen bonds in PAA chains, these injectable MSNs would immediately switch from nanoparticles to compact hydrogels in a tumor environment (37.5 °C, pH 6.8), where the concentrated network structure in the hydrogel is in charge of the loading and local delivery of anti-tumor drugs. The MSNs serve as nanocarriers for growth factors, which are localized by crosslinked networks. The sustained release of growth factors only occurred with the cleavage of hydrogen bonds in PAA chains, which is triggered by the pH increase to 7.4 after the cure of the tumor. Moreover, the hydrogen bond cleavage would also cause the swelling of the hydrogel, which not only fills the defects but generates plenty of cell-level pores, resulting in an excellent scaffold for attachment and proliferation of healthy cells. Therefore, the dual responsive MSN-hydrogels offer a promising strategy for sequential tumor therapy and tissue regeneration.