Derivation of Dental Epithelial-like Cells from Murine Embryonic Stem Cells for Tooth Regeneration.

Teeth are comprised of epithelial and mesenchymal cells, and regenerative teeth rely on the regeneration of both cell types. Transcription factors play a pivotal role in cell fate determination. In this study, we establish fluorescence models based on transcription factors to monitor and analyze dental epithelial cells. Using Pitx2-P2A-copGFP mice, we observe that Pitx2+ epithelial cells, when combined with E14.5 dental mesenchymal cells, are sufficient for the reconstitution of teeth. Induced-Pitx2+ cells, directly isolated from the embryoid body that employs the Pitx2-GFP embryonic stem cell line, exhibit the capacity to differentiate into ameloblasts and develop into teeth when combined with dental mesenchymal cells. The regenerated teeth exhibit a complete structure, including dental pulp, dentin, enamel, and periodontal ligaments. Subsequent exploration via RNA-seq reveals that induced-Pitx2+ cells exhibit enrichment in genes associated with FGF receptors and WNT ligands compared with induced-Pitx2- cells. Our results indicate that both primary Pitx2+ and induced Pitx2+ cells possess the capability to differentiate into enamel-secreting ameloblasts and grow into teeth when combined with dental mesenchymal cells.

Mussel-inspired immunomodulatory and osteoinductive dual-functional hydroxyapatite nanoplatform for promoting bone regeneration.

Simultaneously modulating the inflammatory microenvironment and promoting local bone regeneration is one of the main challenges in treating bone defects. In recent years, osteoimmunology has revealed that the immune system plays an essential regulatory role in bone regeneration and that macrophages are critical components. In this work, a mussel-inspired immunomodulatory and osteoinductive dual-functional hydroxyapatite nano platform (Gold/hydroxyapatite nanocomposites functionalized with polydopamine - PDA@Au-HA) is developed to accelerate bone tissues regeneration by regulating the immune microenvironment. PDA coating endows nanomaterials with the ability to scavenge reactive oxygen species (ROS) and anti-inflammatory properties, and it also exhibits an immunomodulatory ability to inhibit M1 macrophage polarization and activate M2 macrophage secretion of osteogenesis-related cytokines. Most importantly, this nano platform promotes the polarization of M2 macrophages and regulates the crosstalk between macrophages and pre-osteoblast cells to achieve bone regeneration. Au-HA can synergistically promote vascularized bone regeneration through sustained release of Ca and P particles and gold nanoparticles (NPs). This nano platform has a synergistic effect of good compatibility, scavenging of ROS, and anti-inflammatory and immunomodulatory capability to accelerate the bone repair process. Thus, our research offers a possible therapeutic approach by exploring PDA@Au-HA nanocomposites as a bifunctional platform for tissue regeneration.

Patients' perceptions matter: Risk communication and psychosocial factors in orthodontics.

INTRODUCTION: Effective risk communication is essential for achieving patient-centered oral health care, but the limited understanding of patients' subjective perceptions of orthodontic-related risks hinders this process. This study aimed to investigate adults' awareness, concerns, and risk-avoidance behaviors about long-term orthodontic risks, exploring their relationship with psychosocial factors. METHODS: We included 498 adult patients (mean age, 27.3 ± 6.8 years; women, 75.5%) during their initial visits to the orthodontic department at a hospital in Chengdu, China. Participants' understanding of orthodontic risks was gauged before and after exposure to the Oral Health Education Comics (OHEC), a specifically designed digital tool. Concurrently, we used logistic regression models to investigate the associations between patients' depression, anxiety, self-esteem, perfectionism, and dentofacial esthetics with risk perceptions. RESULTS: Approximately 79.5% of participants initially reported low awareness of orthodontic risks, with most knowledge from online sources. Notably, the percentage of participants with high awareness increased to 64.8% after OHEC. The negative facial soft-tissue change was most concerning for participants: 53.4% showed high concerns, and 28.1% showed high avoidance. Furthermore, linear regression indicated positive associations between depression (ß = 0.42 [95% confidence interval {CI}, 0.07-0.77]) and anxiety (ß = 0.76 [95% CI, 0.35-1.18]) with orthodontic risk concerns, whereas risk avoidance was positively associated with depression (ß = 0.62 [95% CI, 0.27-0.97]), anxiety (ß = 1.09 [95% CI, 0.68-1.50]), and perfectionism (ß = 0.24 [95% CI, 0.02-0.46]). CONCLUSIONS: Findings emphasize the imperative of streamlined risk communication in orthodontics. By incorporating comprehensible tools such as OHEC and integrating psychosocial evaluations, more refined patient-practitioner communication and psychosomatic-based dental care can be achieved.

SCL14 Inhibits the Functions of the NAC043-MYB61 Signaling Cascade to Reduce the Lignin Content in Autotetraploid Populus hopeiensis.

Whole-genome duplication often results in a reduction in the lignin content in autopolyploid plants compared with their diploid counterparts. However, the regulatory mechanism underlying variation in the lignin content in autopolyploid plants remains unclear. Here, we characterize the molecular regulatory mechanism underlying variation in the lignin content after the doubling of homologous chromosomes in Populus hopeiensis. The results showed that the lignin content of autotetraploid stems was significantly lower than that of its isogenic diploid progenitor throughout development. Thirty-six differentially expressed genes involved in lignin biosynthesis were identified and characterized by RNA sequencing analysis. The expression of lignin monomer synthase genes, such as PAL, COMT, HCT, and POD, was significantly down-regulated in tetraploids compared with diploids. Moreover, 32 transcription factors, including MYB61, NAC043, and SCL14, were found to be involved in the regulatory network of lignin biosynthesis through weighted gene co-expression network analysis. We inferred that SCL14, a key repressor encoding the DELLA protein GAI in the gibberellin (GA) signaling pathway, might inhibit the NAC043-MYB61 signaling functions cascade in lignin biosynthesis, which results in a reduction in the lignin content. Our findings reveal a conserved mechanism in which GA regulates lignin synthesis after whole-genome duplication; these results have implications for manipulating lignin production.

Effects of polyvinyl chloride microplastics and benzylalkyldimethylethyl compounds on system performance, microbial community and resistance genes in sulfur autotrophic denitrification system.

Benzylalkyldimethylethyl ammonium compounds (BAC) and polyvinyl chloride microplastics (PVC MPs), as the frequently detected pollutants in wastewater treatment plants (WWTPs), have attracted more concerns on their ecosystem risks. Therefore, this study investigated how the sulfur autotrophic denitrification (SAD) system responded to the single and joint stress of PVC MPs (1, 10 and 100 mg/L) and BAC (0.5, 5 and 10 mg/L). After 100 days of operation, the presence of 10 mg/L BAC led to obviously inhibitory effects on system performance and microbial metabolic activity. And the additions of PVC MPs or/and BAC stimulated the proliferation of intracellular resistance genes (RGs), whereas exposure to BAC increased the abundances of extracellular RGs and free RGs in water more significantly. Compared to the joint stress, BAC single stress resulted in higher abundances of free RGs in water, which further increased the risk of RGs propagation. Moreover, the interaction between mobile genetic elements and extracellular polymeric substances further increased the spread of RGs. Pathogens might be the potential hosts of RGs and enriched in SAD system and plastisphere, thereby leading to more serious ecological risks. This study will broaden the understanding of the environmental hazards posed by PVC MPs and BAC in WWTPs.

An injectable dental pulp-derived decellularized matrix hydrogel promotes dentin repair through modulation of macrophage response.

Maintaining the viability of damaged pulp is critical in clinical dentistry. Pulp capping, by placing dental material over the exposed pulp, is a main approach to promote pulp-dentin healing and mineralized tissue formation. The dental materials are desired to impact on intricate physiological mechanisms in the healing process, including early regulation of inflammation, immunity, and cellular events. In this study, we developed an injectable dental pulp-derived decellularized matrix (DPM) hydrogel to modulate macrophage responses and promote dentin repair. The DPM derived from porcine dental pulp has high collagen retention and low DNA content. The DPM was solubilized by pepsin digestion (named p-DPM) and subsequently injected through a 25G needle to form hydrogel facilely at 37 °C. In vitro results demonstrated that the p-DPM induced the M2-polarization of macrophages and the migration, proliferation, and dentin differentiation of human dental pulp stem cells from deciduous teeth (SHEDs). In a mouse subcutaneous injection test, the p-DPM hydrogel was found to facilitate cell recruitment and M2 polarization during the early phase of implantation. Additionally, the acute pulp restoration in rat models proved that injectable p-DPM hydrogel as a pulp-capping agent had excellent efficacy in dentin regeneration. This study demonstrates that the DPM promotes dentin repair by modulating macrophage responses, and has a potential for pulp-capping applications in dental practice.

Recent advances in glass-ceramics: Performance and toughening mechanisms in restorative dentistry.

The use of glass-ceramics in the medical field has grown significantly since the 1980s. With excellent aesthetic properties, semi-translucency, outstanding mechanical properties, corrosion resistance, wear resistance and great biocompatibility and workability glass-ceramics is one of the most commonly used materials in restorative dentistry and is widely used in veneers, inlays, onlays, all-ceramic crowns, and implant abutments. This review provides an overview of the research progress of glass-ceramics in restorative dentistry, focusing on the classification, performance requirements, toughening mechanisms and their association with clinical performance, as well as the manufacturing and fabrication of glass-ceramics in restorative dentistry. Finally, the developments and prospects of glass-ceramics in restorative dentistry are summarized and discussed.

Zwitterionic nanospheres engineered co-polymer composite membrane for precise protein-protein separation via dynamic self-assembly micelle deposition.

The accurate protein-protein separation is important but technically challenging. Achieving such a precise separation using membrane requires the selective channels with appropriate pore geometry structure and high anti-fouling property. In this study, polyethersulfone-b-poly(sulfobetaine methyl methacrylate) (PES-b-PSBMA) was synthesized and engineered onto polysulfone (PSF) ultrafiltration (UF) membrane to fabricate zwitterionic nanospheres engineered co-polymer (ZN-e-CoP) composite membrane via dynamic self-assembly micelle deposition. On the one hand, self-assembly zwitterionic nanospheres were used as blocks to construct hydrophilic layers with size-dependent sieving channels, endowing ZN-e-CoP composite membranes with enhanced permselectivity and protein-protein separation abilities, meanwhile zwitterionic groups from nanospheres reinforced the structure stability of nanospheres/nanospheres and nanospheres/membrane via multiple intermolecular interactions. On the other hand, zwitterionic nanospheres can induce to produce the hydration layer enveloping themselves by binding water molecules, where hydration layer acts as a protective barrier on the membrane surface, impeding the protein adhesion. Hence, ZN-e-CoP_1a composite membrane exhibited superior separation properties with Lysozyme/Bovine Serum Albumin (BSA) separation factor of 18.1 and 95.4 % rejection against BSA, 10.1 and 2.3 times, respectively, higher these of pristine PSF membrane (1.8 and 42.1 %), without obviously sacrificing water flux. Simultaneously, hydration layer enables the ZN-e-CoP_1a membrane with enhanced anti-fouling performance and durability during the long-term operations. The proposed approach opens new pathways to fabricate excellent anti-fouling membranes for precise protein-protein separation.

Bioactivity and in vitro immunological studies of xenogeneic decellularized extracellular matrix scaffolds for implantable applications.

Decellularized scaffolds retain the main bioactive substances of the extracellular matrix, which can better promote cell proliferation and matrix reconstruction at the defect site, and have great potential for morphological and functional restoration in patients with tissue defects. Due to the safety of the material source of allogeneic decellularized scaffolds, there is a great limitation in their clinical application, so the preparation and evaluation of xenodermal acellular scaffolds have attracted much attention. In terms of skin tissue structure and function, porcine skin has a high degree of similarity to human skin and has the advantages of sufficient quantity and no ethical issues. However, there is a risk of immune rejection after xenodermal acellular scaffold transplantation. To address the above problems, this paper focuses on porcine dermal decellularized scaffolds prepared using two common decellularization preparation methods and compares the decellularization efficiency, retention of active components of the extracellular matrix, structural characterization of the decellularized scaffolds, and the effect of porcine dermal decellularized scaffolds on mouse Raw264.7 macrophages, so as to make a functional evaluation of the active components and immune effects of porcine dermal decellularized scaffolds, and to provide a reference for filling trauma-induced defects in humans.

A Janus, robust, biodegradable bacterial cellulose/Ti3C2Tx MXene bilayer membranes for guided bone regeneration.

Guided bone regeneration (GBR) stands as an essential modality for craniomaxillofacial bone defect repair, yet challenges like mechanical weakness, inappropriate degradability, limited bioactivity, and intricate manufacturing of GBR membranes hindered the clinical efficacy. Herein, we developed a Janus bacterial cellulose(BC)/MXene membrane through a facile vacuum filtration and etching strategy. This Janus membrane displayed an asymmetric bilayer structure with interfacial compatibility, where the dense layer impeded cell invasion and the porous layer maintained stable space for osteogenesis. Incorporating BC with Ti3C2Tx MXene significantly enhanced the mechanical robustness and flexibility of the material, enabling clinical operability and lasting GBR membrane supports. It also contributed to a suitable biodegradation rate, which aligned with the long-term bone repair period. After demonstrating the desirable biocompatibility, barrier role, and osteogenic capability in vitro, the membrane's regenerative potential was also confirmed in a rat cranial defect model. The excellent bone repair performance could be attributed to the osteogenic capability of MXene nanosheets, the morphological cues of the porous layer, as well as the long-lasting, stable regeneration space provided by the GBR membrane. Thus, our work presented a facile, robust, long-lasting, and biodegradable BC/MXene GBR membrane, offering a practical solution to craniomaxillofacial bone defect repair.

The Effect of Antibacterial-Osteogenic Surface Modification on the Osseointegration of Titanium Implants: A Static and Dynamic Strategy.

Titanium (Ti) and its alloys are widely used biomaterials in bone repair. Although these biomaterials possess stable properties and good biocompatibility, the high elastic modulus and low surface activity of Ti implants have often been associated with infection, inflammation, and poor osteogenesis. Therefore, there is an urgent need to modify the surface of Ti implants, where changes in surface morphology or coatings loading can confer specific functions to help them adapt to the osseointegration formation phase and resist bacterial infection. This can further ensure a healthy microenvironment for bone regeneration as well as the promotion of immunomodulation, angiogenesis, and osteogenesis. Therefore, in this review, we evaluated various functional Ti implants after surface modification, both in terms of static modifications and dynamic response strategies, mainly focusing on the synergistic effects of antimicrobial activities and functionalized osteogenic. Finally, the current challenges and future perspectives are summarized to provide innovative and effective solutions for osseointegration and bone defect repair.

Copper doped carbon dots modified bacterial cellulose with enhanced antibacterial and immune regulatory functions for accelerating wound healing.

The microenvironment of wound healing is susceptible to bacterial infection, chronic inflammation, oxidative stress, and inadequate angiogenesis, requiring the development of innovative wound dressings with antibacterial, anti-inflammatory, antioxidant, and angiogenic capabilities. This research crafted a new multifunctional bacterial cellulose composite membrane infused with copper-doped carbon dots (BC/Cu(II)-RCDs). Findings validated the successful loading of copper-doped carbon dots onto the BC membrane via hydrogen bonding interactions. Compared to the pure BC membrane, the BC/Cu(II)-RCDs composite membrane exhibited significantly enhanced hydrophilicity, tensile properties, and thermal stability. Diverse in vitro assays demonstrated excellent biocompatibility and antibacterial activity of BC/Cu(II)-RCDs composite membranes, alongside their ability to expedite the inflammatory phase and stimulate angiogenesis. In vivo trials corroborated the membrane's ability to foster epithelial regeneration, collagen deposition, and tissue regrowth in full-thickness skin wounds in rats while also curbing inflammation in infected full-thickness skin wounds. More importantly, the treatment of the BC/Cu(II)-RCDs composite membrane may result in the activation of VEGF and MAPK signaling proteins, which are key players in cell migration, angiogenesis, and skin tissue development. In essence, the developed BC/Cu(II)-RCDs composite membrane shows promise for treating infected wounds and serves as a viable alternative material for medicinal bandages.

A Gas Therapy Strategy for Intestinal Flora Regulation and Colitis Treatment by Nanogel-Based Multistage NO Delivery Microcapsules.

Current approaches to treating inflammatory bowel disease focus on the suppression of overactive immune responses, the removal of reactive intestinal oxygen species, and regulation of the intestinal flora. However, owing to the complex structure of the gastrointestinal tract and the influence of mucus, current small-molecule and biologic-based drugs for treating colitis cannot effectively act at the site of colon inflammation, and as a result, they tend to exhibit low efficacies and toxic side effects. In this study, nanogel-based multistage NO delivery microcapsules are developed to achieve NO release at the inflammation site by targeting the inflammatory tissues using the nanogel. Surprisingly, oral administration of the microcapsules suppresses the growth of pathogenic bacteria and increases the abundance of probiotic bacteria. Metabolomics further show that an increased abundance of intestinal probiotics promotes the production of metabolites, including short-chain fatty acids and indole derivatives, which modulate the intestinal immunity and restore the intestinal barrier via the interleukin-17 and PI3K-Akt signaling pathways. This work reveals that the developed gas therapy strategy based on multistage NO delivery microcapsules modulates the intestinal microbial balance, thereby reducing inflammation and promoting intestinal barrier repair, ultimately providing a new therapeutic approach for the clinical management of colitis.

Single-cell RNA-seq of in vitro expanded cells from cranial neural crest reveals a rare odontogenic sub-population.

Ecto-mesenchymal cells of mammalian tooth germ develops from cranial neural crest cells. These cells are recognised as a promising source for tooth development and regeneration. Despite the high heterogeneity of the neural crest, the cellular landscape of in vitro cultured cranial neural crest cells (CNCCs) for odontogenesis remains unclear. In this study, we used large-scale single-cell RNA sequencing to analyse the cellular landscape of in vitro cultured mouse CNCCs for odontogenesis. We revealed distinct cell trajectories from primary cells to passage 5 and identified a rare Alx3+/Barx1+ sub-population in primary CNCCs that differentiated into two odontogenic clusters characterised by the up-regulation of Pax9/Bmp3 and Lhx6/Dmp1. We successfully induced whole tooth-like structures containing enamel, dentin, and pulp under the mouse renal capsule using in vitro cultured cells from both cranial and trunk neural crests with induction rates of 26.7% and 22.1%, respectively. Importantly, we confirmed only cells sorted from odontogenic path can induce tooth-like structures. Cell cycle and DNA replication genes were concomitantly upregulated in the cultured NCCs of the tooth induction groups. Our data provide valuable insights into the cell heterogeneity of in vitro cultured CNCCs and their potential as a source for tooth regeneration.

Recent advances in composite hydrogels: synthesis, classification, and application in the treatment of bone defects.

Bone defects are often difficult to treat due to their complexity and specificity, and therefore pose a serious threat to human life and health. Currently, the clinical treatment of bone defects is mainly surgical. However, this treatment is often more harmful to patients and there is a potential risk of rejection and infection. Hydrogels have a unique three-dimensional structure that can accommodate a variety of materials, including particles, polymers and small molecules, making them ideal for treating bone defects. Therefore, emerging composite hydrogels are considered one of the most promising candidates for the treatment of bone defects. This review describes the use of different types of composite hydrogel in the treatment of bone defects. We present the basic concepts of hydrogels, different preparation techniques (including chemical and physical crosslinking), and the clinical requirements for hydrogels used to treat bone defects. In addition, a review of numerous promising designs of different types of hydrogel doped with different materials (e.g., nanoparticles, polymers, carbon materials, drugs, and active factors) is also highlighted. Finally, the current challenges and prospects of composite hydrogels for the treatment of bone defects are presented. This review will stimulate research efforts in this field and promote the application of new methods and innovative ideas in the clinical field of composite hydrogels.

Invisalign Treatment of a Three-Year-Old Child with Bilateral Posterior Scissor Bite and Multisite Upper Airway Obstruction: A Case Report.

BACKGROUND: Scissor bites have been reported in relatively few epidemiological studies because of their extremely low prevalence rate (below 1%). The etiology of scissor bites remains obscure, but its impact on growth and function should not be ignored. METHODS: In this case report, a novel treatment that utilizes Invisalign aligners was performed on a 3-year-old child who presented with a bilateral posterior scissor bite and anterior crossbite, accompanied by multisite obstruction in the upper airway. The aligners functioned as occlusion pads to unlock the scissor bite relationship and combined with cross-traction to narrow the maxillary arch and enlarge the mandibular arch simultaneously. RESULTS: The duration of orthodontic therapy was 28 weeks. A multidisciplinary consultation (orthodontics department, ENT department, and spinal surgery) was conducted and a stable result was achieved. A healthy occlusal relationship, improved dental esthetics and a better lateral profile were eventually obtained. CONCLUSIONS: Positive treatment outcomes rely on patients' good compliance in this case. In addition, we hope that clinicians will consider our situation in terms of alternative treatments and interprofessional experience.

Current Perspectives on Paradental Cyst: A Literature Review.

Paradental cyst (PC) is an uncommon type of odontogenic cyst of inflammatory origin, which develops near the cervical margin of the outside of the root of a vital tooth. The category of paradental cyst includes the buccal bifurcation cyst, which is found in the buccal area adjacent to the mandibular first or second molars in children. A conclusive diagnosis of a PC needs to correlate the surgical, radiographic, and histologic findings. When strict diagnosis is neglected, they can be easily misdiagnosed and mistreated. PCs associated with mandibular first and second molars and those associated with the mandibular third molar may have slightly different clinical manifestations but have almost completely different treatment principles due to the distinction in location. For the third molars, removal of both the tooth and the cyst is preferred. However, when the first or second molars are affected, it may be advisable to perform enucleation of the lesion while preserving the associated tooth. There are also more conservative methods to retain vital permanent teeth within the mandibular arch. Additionally, the cyst wall primarily consisted of granulation tissue firmly attached to the periodontal ligament space. The exact origin of these cysts was a subject of ongoing debate, but they were believed to primarily arise from either the reduced enamel epithelium or the inflammatory proliferation of junctional/sulcular epithelium, which originate from the superficial mucosa during tooth eruption. The aim of the present review was to update information on clinical manifestations, diagnosis and treatment strategies of cysts and discuss their pathogenic mechanisms. Raising familiarity with the distinctive features is beneficial for accurately diagnosing these lesions and effectively caring for the patients.

Fates of extracellular and intracellular antibiotic resistance genes in activated sludge and plastisphere under sulfadiazine pressure.

Microplastics, antibiotics, and antibiotic resistance genes (ARGs) represent prominent emerging contaminants that can potentially hinder the efficacy of biological wastewater treatment and pose health risks. Plastisphere as a distinct ecological niche for microorganisms, acts as a repository for ARGs and potential pathogenic bacteria. Nonetheless, the spread pattern of extracellular ARGs (eARGs) and intracellular ARGs (iARGs) in plastisphere under antibiotic exposure was not yet known. This study aimed to investigate disparities in extracellular polymeric substances (EPS) production, extracellular and intracellular microbial community structures, as well as the transmission of eARGs and iARGs between activated sludge and plastisphere in an anaerobic/anoxic/oxic system under sulfadiazine (SDZ) exposure. SDZ was found to enhance EPS production in activated sludge and plastisphere. Interestingly, as SDZ removal efficiency increased, EPS content decreased in activated sludge and plastisphere collected from oxic zone, and continued to increase in plastisphere samples collected from anaerobic and anoxic zones. There were significant differences in microbial community structure between activated sludge and plastisphere, and the DNA fragments of potential pathogenic bacteria were detected in extracellular samples. SDZ exhibited a promoting effect on the propagation of eARGs, which were more abundant in the plastisphere than in activated sludge, thus heightening the risk of ARGs dissemination. Extracellular mobile genetic elements played a pivotal role in driving the spread of eARGs, while the microbial community induced the changes of iARGs. Potential pathogenic bacteria emerged as potential hosts for ARGs and mobile genetic elements within activated sludge and plastisphere, leading to more serious environmental threats.

The responses of microbial metabolic activity, bacterial community and resistance genes under the coexistence of nanoplastics and quaternary ammonium compounds in the sewage environment.

Nanoplastics (NPs) and quaternary ammonium compounds (QACs) are frequently detected in sewage. However, little is known about the risks of coexistence of NPs and QACs. In this study, the responses of microbial metabolic activity, bacterial community and resistance genes (RGs) to the exposure of polyethylene (PE), polylactic acid (PLA), silicon dioxide (SiO2) and dodecyl dimethyl benzyl ammonium chloride (DDBAC) were focused on 2nd and 30th day of incubation in sewer environment. Bacterial community contributed 25.01 % to shape RGs and mobile genetic elements (MGEs) after two days of incubation in sewage and plastisphere. After 30 days of incubation, the most important individual factor (35.82 %) was turned to microbial metabolic activity. The metabolic capacity of the microbial communities in plastisphere was stronger than that from SiO2 samples. Moreover, DDBAC inhibited the metabolic capacity of microorganisms in sewage samples, and increased the absolute abundances of 16S rRNA in plastisphere and sewage samples which might be similar to the hormesis effect. After 30 days of incubation, Aquabacterium was the predominant genus in plastisphere. As for SiO2 samples, Brevundimonas was the predominant genus. QACs RGs (qacEdelta1-01, qacEdelta1-02) and antibiotic RGs (ARGs) (aac(6')-Ib, tetG-1) significantly enriched in plastisphere. There was also co-selection among qacEdelta1-01, qacEdelta1-02 and ARGs. In addition, VadinBC27 which enriched in plastisphere of PLA NPs was positively correlated with the potentially disease-causing genus Pseudomonas. It showed that after 30 days of incubation, plastisphere had an important effect on distribution and transfer of pathogenic bacteria and RGs. Plastisphere of PLA NPs also carried the risk of spreading disease.

Co-transport of degradable microplastics with Cd(â ¡) in saturated porous media: Synergistic effects of strong adsorption affinity and high mobility.

With the utilization of degradable plastics in the agricultural film and packaging industries, degradable microplastics (MPs) with strong mobility distributed in the underground environment may serve as carriers for heavy metals. It is essential to explore the interaction of (aged) degradable MPs with Cd(Ⅱ). The adsorption and co-transport behavior of different types of (aged) MPs (polylactic acid (PLA), polyvinyl chloride (PVC)) with Cd(Ⅱ) were investigated through batch adsorption experiments and column experiments under different conditions, respectively. The adsorption results showed that the adsorptive capacity of (aged) PLA with O-functional groups, polarity, and more negative charges was stronger than that of PVC and aged PVC, which was attributed to the binding of (aged) PLA to Cd(Ⅱ) through complexation and electrostatic attraction. The co-transport results indicated that the promotion of Cd(Ⅱ) transport by MPs followed the order of aged PLA > PLA > aged PVC > PVC. This facilitation was more pronounced under conditions of stronger transport of MPs and favorable attachment of Cd(Ⅱ) to MPs. Overall, the combination of strong adsorption affinity and high mobility helped (aged) PLA act as effective carriers for Cd(Ⅱ). The DLVO theory well explains the transport behavior of Cd(Ⅱ)-MPs. These findings provide new insights into the co-transport of degradable MPs and heavy metals in the subsurface environment.