You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["HealthCareActivity", "InjuryOrPoisoning", "BodySubstance", "IntellectualProduct", "AnatomicalStructure", "SpatialConcept", "Chemical", "Bacterium", "MedicalDevice", "Organization", "BiomedicalOccupationOrDiscipline", "Finding", "BiologicFunction", "Virus", "ResearchActivity", "ClinicalAttribute", "PopulationGroup", "Eukaryote", "BodySystem", "Food", "ProfessionalOrOccupationalGroup"].

Please return the output as a JSON object of the format: {"Virus": ["HIV", ...], "Bacterium": ["MRSA", ...], "AnatomicalStructure": ["Lung", ...], "BodySystem": ["CNS", ...], "BodySubstance": ["Serum", ...], "Finding": ["Headache", ...], "InjuryOrPoisoning": ["Fracture", ...], "BiologicFunction": ["Death", ...], "HealthCareActivity": ["Biopsy", ...], "ResearchActivity": ["Clinical trial", ...], "MedicalDevice": ["Lenses", ...], "SpatialConcept": ["Camps", ...], "BiomedicalOccupationOrDiscipline": ["Forensic medicine", ...], "Organization": ["WHO", ...], "ProfessionalOrOccupationalGroup": ["Provider", ...], "PopulationGroup": ["Swimmers", ...], "Chemical": ["Gold", ...], "Food": ["Rice", ...], "IntellectualProduct": ["RPAM", ...], "ClinicalAttribute": ["Biomarker", ...], "Eukaryote": ["Dogs", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Fabrication of gelatin methacrylate / nanohydroxyapatite microgel arrays for periodontal tissue regeneration Periodontitis is a chronic infectious disease and is the major cause of tooth loss and other oral health issues around the world. Periodontal tissue regeneration has therefore always been the ultimate goal of dentists and researchers. Existing fabrication methods mainly focused on a top-down tissue engineering strategy in which several drawbacks remain, including low throughput and limited diffusion properties resulting from a large sample size. Gelatin methacrylate (GelMA) is a kind of photocrosslinkable and biocompatible hydrogel, with the capacities of enabling cell encapsulation and regeneration of functional tissues. Here, we developed a novel method to fabricate GelMA / nanohydroxylapatite (nHA) microgel arrays using a photocrosslinkable strategy. The viability, proliferation, and osteogenic differentiation and in vivo osteogenesis of human periodontal ligament stem cells (hPDLSCs) encapsulated in microgels were evaluated. The results suggested that such microgels provide great potential for periodontal tissue repair and regeneration. Microgel arrays were fabricated by blending different weight ratios of GelMA and nHA. hPDLSCs were encapsulated in GelMA / nHA microgels of various ratios for a systematic evaluation of cell viability, proliferation, and osteogenic differentiation. In vivo osteogenesis in nude mice was also studied. The GelMA / nHA microgels exhibited appropriate microarchitecture, mechanical strength, and surface roughness, thus enabling cell adhesion and proliferation. Additionally, the GelMA / nHA microgels (10%/2% w/v) enhanced the osteogenic differentiation of hPDLSCs by elevating the expression levels of osteogenic biomarker genes, such as ALP, BSP, OCN, and RUNX2. In vivo ectopic transplantation results showed that GelMA / nHA microgels (10%/2% w/v) increased mineralized tissue formation with abundant vascularization, compared with the 1%, 3%, and the pure GelMA group. The GelMA / nHA microgels (10%/2% w/v) facilitated hPDLSCs viability, proliferation, and osteogenic differentiation in vitro and further promoted new bone formation in vivo, suggesting that the GelMA / nHA microgels (10%/2% w/v) provide great potential for periodontal tissue regeneration.
{"AnatomicalStructure": ["tooth loss", "hPDLSCs", "OCN", "ALP", "periodontal ligament", "genes", "mineralized tissue", "RUNX2", "stem cells", "BSP"], "Bacterium": [], "BiologicFunction": ["osteogenesis", "proliferation", "osteogenic differentiation", "cell adhesion", "viability", "Periodontitis", "enabling", "regeneration of functional tissues", "chronic infectious disease", "cell viability", "bone formation"], "BiomedicalOccupationOrDiscipline": [], "BodySubstance": [], "BodySystem": [], "Chemical": ["nanohydroxylapatite", "biocompatible", "GelMA", "gelatin methacrylate", "nanohydroxyapatite", "microgel", "GelMA group", "hydrogel", "Microgel", "Gelatin methacrylate", "microgels", "nHA"], "ClinicalAttribute": ["osteogenic biomarker"], "Eukaryote": ["human", "nude mice"], "Finding": ["issues", "remain", "major cause"], "Food": [], "HealthCareActivity": ["transplantation", "evaluation", "Periodontal tissue regeneration", "evaluated", "top-down tissue engineering", "periodontal tissue repair and regeneration", "periodontal tissue regeneration", "oral health", "cell encapsulation"], "InjuryOrPoisoning": [], "IntellectualProduct": ["methods", "ultimate goal"], "MedicalDevice": [], "Organization": [], "PopulationGroup": ["world"], "ProfessionalOrOccupationalGroup": ["researchers", "dentists"], "ResearchActivity": [], "SpatialConcept": ["surface", "in vivo", "further", "ectopic", "In vivo", "arrays"], "Virus": []}