Long-term Functional Stability Research Articles

Differential intrinsic firing properties in sustained and transient mouse alpha RGCs match their light response characteristics and persist during retinal degeneration.

Retinal ganglion cells (RGCs) are the neuronal connections between the eye and the brain conveying multiple features of the outside world through parallel pathways. While there is a large body of literature how these pathways arise in the retinal network, the process of converting presynaptic inputs into RGC spiking output is little understood. In this study, we show substantial differences in the spike generator across three types of alpha RGCs in female and male mice, the αON sustained, αOFF sustained and αOFF transient RGC. The differences in their intrinsic spiking responses match the differences of the light responses across RGC types. While sustained RGC types have spike generators that are able to generate sustained trains of action potentials at high rates, the transient RGC type fired shortest action potentials enabling it to fire high-frequency transient bursts. The observed differences were also present in late-stage photoreceptor-degenerated retina demonstrating long-term functional stability of RGC responses even when presynaptic circuitry is deteriorated for long periods of time. Our results demonstrate that intrinsic cell properties support the presynaptic retinal computation and are, once established, independent of them.Significance Statement Spiking output from retinal ganglion cells (RGCs) has long been thought to be solely determined by synaptic inputs from the retinal network. We show that the cell-intrinsic spike generator varies across RGC populations and therefore that postsynaptic processing shapes retinal spiking output in three types of mouse alpha RGCs (αRGCs). While sustained αRGC types have spike generators that are able to generate sustained trains of action potentials at high rates, the transient αRGC type fired shortest action potentials enabling them to fire high-frequency transient bursts. Computational modeling suggests that intrinsic response differences are not driven by dendritic morphology but by somatodendritc biophysics. After photoreceptor degeneration, the observed variability is preserved indicating stable physiology across the three αRGC types.

Surface Degradation of Mg2X-Based Composites at Room Temperature: Assessing Grain Boundary and Bulk Diffusion Using Atomic Force Microscopy and Scanning Electron Microscopy.

Practical application of thermoelectric generators necessitates materials that combine high heat-to-electricity conversion efficiency with long-term functional stability under operation conditions. While Mg2(Si,Sn)-based materials exhibit promising thermoelectric properties and module prototypes have been demonstrated, their stability remains a challenge, demanding thorough investigation. Utilizing atomic force microscopy (AFM) and scanning electron microscopy (SEM), we investigate the surface degradation of a composite material comprising Si-rich and Sn-rich Mg2(Si,Sn) solid solutions. The investigation reveals a pronounced dependence of stability on Sn content, with the Sn-rich phase Mg2Si0.13Sn0.87 displaying the formation of a nonprotective oxide layer. Subsequent AFM measurements provide evidence of dominating grain boundary diffusion of loosely bound Mg, compared to bulk diffusion, observed within a few days, ultimately resulting in a complete surface oxidation of the Sn-rich phase within several weeks. On the other hand, Mg2Si and Si-rich Mg2Si0.80±0.05Sn0.20±0.05 remain stable against Mg diffusion to the surface even after prolonged exposure. Comparison with previous investigations confirms that the degradation rate is found to be highly dependent on the Sn content, with markedly higher rates observed for x = 0.87 compared to x = 0.70 in Mg2Si1-xSnx. These findings contribute to a better understanding of the stability challenges associated with Mg2(Si,Sn)-based materials, essential for the development of robust thermoelectric materials for practical applications.

Lipo-Xenopeptide Polyplexes for CRISPR/Cas9 based Gene editing at ultra-low dose

Double pH-responsive xenopeptide carriers containing succinoyl tetraethylene pentamine (Stp) and lipo amino fatty acids (LAFs) were evaluated for CRISPR/Cas9 based genome editing. Different carrier topologies, variation of LAF/Stp ratios and LAF types as Cas9 mRNA/sgRNA polyplexes were screened in three different reporter cell lines using three different genomic targets (Pcsk9, eGFP, mdx exon 23). One U-shaped and three bundle (B2)-shaped lipo-xenopeptides exhibiting remarkable efficiencies were identified. Genome editing potency of top carriers were observed at sub-nanomolar EC50 concentrations of 0.4 nM sgRNA and 0.1 nM sgRNA for the top U-shape and top B2 carriers, respectively, even after incubation in full (≥ 90%) serum. Polyplexes co-delivering Cas9 mRNA/sgRNA with a single stranded DNA template for homology directed gene editing resulted in up to 38% conversion of eGFP to BFP in reporter cells. Top carriers were formulated as polyplexes or lipid nanoparticles (LNPs) for subsequent in vivo administration. Formulations displayed long-term physicochemical and functional stability upon storage at 4 °C. Importantly, intravenous administration of polyplexes or LNPs mediated in vivo editing of the dystrophin gene, triggering mRNA exon 23 splicing modulation in dystrophin-expressing cardiac muscle, skeletal muscle and brain tissue.

141 Motor and Somatosensory Applications for Nerve Cuff Electrodes in Clinical Neuroprosthesis and Neurorehabilitation

INTRODUCTION: Surgically implanted neuroprosthetics aim to restore motor and somatosensory function by delivering controlled electrical impulses to paralyzed nerves. Recently, nerve cuff electrodes (NCEs) have been increasingly studied and may eventually offer the potential to recover somatomotor function in patients with neurologic injury. METHODS: The PubMed, Google Scholar, and Web of Science databases were searched to identify relevant articles published between 2012 – 2022 describing use of neuroprosthetic NCEs for clinical somatomotor rehabilitation. Data from all relevant articles retrieved were collected and summarized. RESULTS: NCE-neural interfaces can restore both upper and lower extremity motor function in spinal cord injury patients and may provide a treatment modality superior to that of muscle-based electrodes. The search yielded 137 studies, and of those reviewed, 18 were original research articles that used peripheral nerve stimulation to elicit motor actions and/or somatosensory perceptions through NCEs. 10 studies looked at restoring motor function in patients with spinal cord injuries or stroke-related paralysis and 7 studies looked at somatosensory applications of NCEs in patients with amputations. Currently, sensory NCE interfacing can restore and improve multiple aspects of sensation in amputees. While there is room for further study in various applications, technological improvements and wider clinical adoption, NCEs have been demonstrated to provide a clinically acceptable option in reducing intraoperative duration and morbidity, while preserving long-term functional stability, threshold charge maintenance, and acceptable mechanical failure rates. CONCLUSIONS: NCEs appear to be a promising avenue for future research in the field of neuroprosthetics. As the translational avenue continues to mature and more clinical studies become avaiable, the utility of NCEs will be better understood.

Multifunctional C/TiO 2 from MXene/Polyaniline for Electromagnetic Protection and Supercapacitor

Enormous endeavors have been made to cope with microwave pollution and energy crisis. Here, porous nitrogen-doped C/TiO 2 composites with absorption/shielding/supercapacitor functions were derived from MXene/polyaniline. It was discovered that KOH acted as porogen and had an etching–bridging–reaction effect during the activation process. As a microwave absorber, the composite/paraffin with a filler loading of 16 wt% reaches a minimum reflection loss of −52.8 dB and an effective absorption bandwidth of 4.72 GHz. Moreover, microwave absorption can be maintained within 45 days in air. Compared with untreated MXene, the absorber shows long-term functional stability in an oxygen-containing environment. As for electromagnetic interference shielding, the composite/paraffin at a filler loading of 50 wt% achieves 30.5 dB from 8.0 to 12.4 GHz. Additionally, the heterostructure delivers a desirable specific capacitance of 1,096.3 F g −1 at 0.5 A g −1 . The trifunctional characteristics enrich the application trials of MXene derivatives and satisfy the strong need for versatile materials.

Multi-lineage heart-chip models drug cardiotoxicity and enhances maturation of human stem cell-derived cardiovascular cells.

Cardiovascular toxicity causes adverse drug reactions and may lead to drug removal from the pharmaceutical market. Cancer therapies can induce life-threatening cardiovascular side effects such as arrhythmias, muscle cell death, or vascular dysfunction. New technologies have enabled cardiotoxic compounds to be identified earlier in drug development. Human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs) and vascular endothelial cells (ECs) can screen for drug-induced alterations in cardiovascular cell function and survival. However, most existing hiPSC models for cardiovascular drug toxicity utilize two-dimensional, immature cells grown in static culture. Improved in vitro models to mechanistically interrogate cardiotoxicity would utilize more adult-like, mature hiPSC-derived cells in an integrated system whereby toxic drugs and protective agents can flow between hiPSC-ECs that represent systemic vasculature and hiPSC-CMs that represent heart muscle (myocardium). Such models would be useful for testing the multi-lineage cardiotoxicities of chemotherapeutic drugs such as VEGFR2/PDGFR-inhibiting tyrosine kinase inhibitors (VPTKIs). Here, we develop a multi-lineage, fully-integrated, cardiovascular organ-chip that can enhance hiPSC-EC and hiPSC-CM functional and genetic maturity, model endothelial barrier permeability, and demonstrate long-term functional stability. This microfluidic organ-chip harbors hiPSC-CMs and hiPSC-ECs on separate channels that can be subjected to active fluid flow and rhythmic biomechanical stretch. We demonstrate the utility of this cardiovascular organ-chip as a predictive platform for evaluating multi-lineage VPTKI toxicity. This study may lead to the development of new modalities for the evaluation and prevention of cancer therapy-induced cardiotoxicity.

Metabolic Plasticity Endows Mixotrophic Organisms with High Tolerance to Cadmium and Special Potential for Recovering Cadmium-Contaminated Aquatic Environment.

Heavy metal pollution in waters causes serious stress to aquatic ecosystems. Several autotrophs with strong tolerance are extensively used to adsorb heavy metals, but their use may be limited by the specific conditions of polluted waters due to their single nutrition mode. By contrast, mixotrophs possess strong environmental adaptability due to their plastic metabolic modes. However, studies focusing on mixotroph's resistance and its underlying mechanism in response to heavy metals and their bioremediation potentials are currently lacking. In this study, we investigated the population, phytophysiological, and transcriptomic (RNA-Seq) responses of a typical and common mixotrophic organism, Ochromonas, to cadmium exposure and then evaluated their capacity to remove cadmium under mixotrophic condition. Compared with autotrophy, mixotrophic Ochromonas enhanced photosynthetic performances under short-time cadmium exposure and subsequently shifted to stronger resistance with increasing exposure time. Transcriptomic analyses suggested that the genes related to photosynthesis, ATP production, ECM components, and scavenging of reactive oxygen species and damaged organelles were upregulated to boost mixotrophic Ochromonas resistance to cadmium. Consequently, the harm of metal exposure was eventually reduced and cellular stability was maintained. Approximately, 70% of cadmium at 2.4 mg L-1 cadmium was removed by mixotrophic Ochromonas in the end, benefiting from upregulated genes associated with the transport of metal ions. Hence, mixotrophic Ochromonas tolerance to cadmium can be attributed to multiple pathways of energy metabolism and effective transport of metal ions. Collectively, this study advanced a better understanding of the unique mechanism of heavy metal resistance in mixotrophs and their potential use in recovering cadmium-contaminated aquatic ecosystems. IMPORTANCE Mixotrophs widely living in aquatic ecosystems possess unique ecological roles and strong environmental adaptability due to their plastic metabolic modes; however, little is known about their underlying resistance mechanism and bioremediation potential in response to environmental stresses. For the first time, this work investigated how mixotrophs respond to metal pollutants through physiological, population dynamics, and transcriptional regulation, and highlighted the unique underlying mechanism of mixotrophs to resist and remove heavy metal, thereby advancing our understanding of the potentials of mixotrophs in recovering metal-contaminated aquatic environments. These unique properties in mixotrophs are essential for the long-term functional stability of aquatic ecosystems.

Long-term taxonomic and functional stability of the gut microbiome from human fecal samples

Appropriate storage of fecal samples is a critical step for unbiased analysis in human microbiome studies. The purpose of this study was to evaluate the stability of the fecal microbial community for up to 18 months. Ten healthy volunteers provided fecal samples at the Jeonbuk National University Hospital. Stool samples were stored under the following six conditions: four different storage temperatures (− 70 °C, − 20 °C, 4 °C, and room temperature [20–25 °C]) and two different collection tubes (OMNIgene-Gut and DNA/RNA shield-fecal collection tubes). The gut microbiome was analyzed with 16S rRNA sequencing. We compared the taxonomic composition, alpha diversity, beta diversity and inferred pathway abundance between the baseline and 18 months after storage. Samples collected in the DNA/RNA Shield-fecal collection tubes showed the best performance in preservation of the taxonomic composition at 18 months. Pairwise differences in alpha diversity metrics showed the least deviation from zero. The PERMANOVA test showed non-significant change of beta diversity metrics (Unweighted Unifrac: q-value 0.268; Weighted Unifrac: q-value 0.848). The functional stability was significantly well preserved in the DNA/RNA Shield-fecal collection tubes (adjusted p value < 0.05). Our results demonstrate the use of the DNA/RNA Shield-fecal collection tube as an alternative storage method for fecal samples to preserve the taxonomic and functional stability of the microbiome over a long term.

Treatment of Dupuytren's Disease with Post-Interventional Radiotherapy

<h3>Purpose/Objective(s)</h3> Ongoing clinical studies are currently testing the benefit of radiotherapy (RT) in Dupuytren Disease (DD) early after interventions used to release a contracture in order to reduce the chances of re-contracture and prevent non-operated areas forming new contractures. Those interventions are needle fasciotomy (NF), collagenase injection (CI) and limited fasciectomy (LF). This phase I-II study summarizes patients with advanced DD treated between 2005 - 2020 using post-interventional RT with follow-up of at least 1 year (mean 5.5, range 1 – 15 years). <h3>Materials/Methods</h3> Patients underwent RT at four different practices organized by a single radiation oncologist (HS) and were divided in two groups: Group A: Early post-interventional RT (given 2-12 weeks after intervention) A1, post-NF: n=25 patients, Male: Female ratio = 15:8; age range 38–73y, 29 hands treated A2, post-CI: n=7: M: F = 4:3, age 41–74y, total 7 hands A3, post-LF: n=19: M: F = 11:8, age 35-71y, total 19 hands Group B: Delayed post-interventional RT (given 4 to 48 months after intervention) B, delayed RT: n=48, M: F = 30:18, age 31–76, total 53 hands All groups received two series of 15Gy in daily fractions of 5 × 3Gy with a 10-12 weeks interval up to 30Gy total dose in 10 fractions. All groups apart from group A3 received RT in two RT-series to the whole palm for both phases while in group A3 the 2nd RT series excluded the LF site. RT Timing: In groups A1 and A2, RT was started 2-4 weeks after intervention. In group A3 RT was started 6-12 weeks after intervention after local healing was completed. In group B, RT was started at least 4 months after intervention. The international "DD progression" criterion was used and defined as increased angulation deficit of at least 20 degrees in any of the involved fingers. Proven progression was categorized as either within or outside the previously operated area. <h3>Results</h3> Long-term functional stability w/o progression was evaluated in 12-2020 and achieved in 83% of Group A1 hands, in 57% of group A2, 90% in group A3, and 86% hands in group B. Minor progression with functional change of up to 10 degrees after RT occurred in 32/108 (30%) and up to 20 degrees in 15/108 (14%) hands. Symptoms such as pain, burning and itching were reduced in 57 of 73 (78%) affected pts. Cosmetic and functional outcome were judged to be "excellent" in 26 (24%), "good" in 38 (35%), "satisfactory" in 17 (16%) and "poor" or "unsatisfactory" in 27 (25%) sites. RT Side effects were long-term dryness in 43 of 108 (40%) sites; no deep wounds or ulcers or post-interventional infections were observed. <h3>Conclusion</h3> This is the first clinical study published demonstrating that post-interventional RT is an effective and safe addition to minimal non-invasive (NF and CI) and limited invasive (PNF) procedures to preserve improvements in hand function after intervention. Further controlled clinical studies supported by IORBC are required to optimize RT indication, specific selection criteria, interdisciplinary collaboration and applied RT dose concepts.

Wheat straw-core hydrogel spheres with polypyrrole nanotubes for the removal of organic dyes

Straw biomass is an underutilized raw material, the use of which could make a significant contribution to sustainable development. Herein, wheat straw waste was regenerated into novel porous core-shell wheat straw-polypyrrole hydrogel spheres for the removal of dyes from wastewater. Adsorption experiments demonstrated that the hydrogel spheres had long-term structural and functional stability, and a high performance for the removal of the water-soluble model anionic dye eosin Y (EY). The maximum adsorption capacity of the hybrid spheres (520.2 mg/g) was 12 times greater than that of the wheat straw hydrogel sphere. Recycling experiments showed that it the initial adsorption capacity of 75.0% could be maintained after seven adsorption-desorption cycles, and the material could be recovered by simple filtration. The results from spectroscopic (FTIR, XPS) analysis, adsorption experiments and computational quantum mechanical modelling suggested that hydrogen bonds, π-π stacking and electrostatic forces, were involved in the removal of EY from aqueous solution. Interestingly, the hydrogel sphere exhibited enhanced adsorption at elevated temperature, and this could be attributed to the dynamic breaking of crosslinked hydrogen bonds in the hydrogel sphere and release of activated –OH. The results from this study provide a basis for the development of sustainable high-performance adsorption materials from wheat straw biomass for the removal of organic dyes from wastewater. It also provides a strategy to design adsorbents that work efficiently at elevated temperatures.

Hybrid Bone-Grafting Technique for Staged Revision Anterior Cruciate Ligament Reconstruction.

Hybrid Bone-Grafting Technique for Staged Revision Anterior Cruciate Ligament Reconstruction.

Graphene on glassy carbon microelectrodes demonstrate long-term structural and functional stability in neurophysiological recording and stimulation

Objective. There is a growing interest in the use of carbon and its allotropes for microelectrodes in neural probes because of their inertness, long-term electrical and electrochemical stability, and versatility. Building on this interest, we introduce a new electrode material system consisting of an ultra-thin monoatomic layer of graphene (Gr) mechanically supported by a relatively thicker layer of glassy carbon (GC). Approach. Due to its high electrical conductivity and high double-layer capacitance, Gr has impressive electrical and electrochemical properties, two key properties that are useful for neural recording and stimulation applications. However, because of its two-dimensional nature, Gr exhibits a lack of stiffness in the transverse direction and hence almost non-existent flexural and out-of-plane rigidity that will severely limit its wider use. On the other hand, GC is one of carbon’s important allotropes and consists of three-dimensional microstructures of Gr fragments with a natural molecular similarity to Gr. Further, GC has exceptional chemical inertness, good electrical properties, high electrochemical stability, purely capacitive charge injection, and fast surface electrokinetics coupled with lithography patternability. This makes GC an ideal candidate for addressing Gr’s lack of out-of-plane rigidity through providing a matching sturdier and robust mechanical backing. Combining the strengths of these two allotropes of carbon, we introduce a new neural probe that consists of ∼1 nm thick layer of patterned Gr microelectrodes supported by another layer of 3–5 μm thick patterned GC. Main results. We present the fabrication technology for the new Gr on GC (graphene on glassy carbon) microelectrodes and the accompanying pattern transfer technology on flexible substrate and report on the bond between these two allotropes of carbon through FTIR, surface morphology through SEM, topography through atomic force microscopy, and microstructure imaging through scanning transmission electron microscopy. A long-term (18 weeks) in vivo study of the use of these Gr on GC microelectrodes assessed the quality of the electrocorticography-based neural signal recording and stimulation through electrophysiological measurements. The probes were demonstrated to be functionally and structurally stable over the 18 week period with minimal glial response—the longest reported so far for Gr-based microelectrodes. Significance. The Gr on GC microelectrodes presented here offers a compelling case for expanding the potentials of Gr-based technology in the broad areas of neural probes.

Developing a Multifunctional Silk Fabric with Dual-Driven Heating and Rapid Photothermal Antibacterial Abilities Using High-Yield MXene Dispersions.

Two-dimensional material titanium carbide (Ti3C2Tx MXene) has been widely used for building diverse functional materials; however, the disadvantages of unsatisfactory yield and low concentration during the preparation process generally limit its large-scale promotion. In the present work, an MXene dispersion with enhanced yield (90%), high concentration (45 mg/mL), and excellent dispersibility was successfully prepared. Subsequently, the active MXene nanosheets were effectively in situ deposition onto the silk fiber by means of dip-coating, relying on van der Waals forces and hydrogen bonds. The obtained MXene-decorated silk fabric (MXene@silk) exhibits satisfactory electrical conductivity (170 mS/cm), excellent photothermal and electrothermal conversion properties, especially dual-drive energy conversion, rapid thermal responses, and long-term functional stability. Furthermore, UV protection factor of the fabric, and its antibacterial efficiency against Gram-negative Escherichia coli (E. coli) within 20 min of contact reach over 110 and 99%, respectively, demonstrating remarkable UV resistance and rapid photothermal antibacterial ability. Meanwhile, the fabric of MXene@silk still retains the original characteristics of breathability, softness, and skin-friendly properties compared to the untreated. The multifunctional fabric constructed through a facile and high-yield strategy shows a noticeable potential applying to smart textiles to meet people's multipurpose needs in the future.

Long-term functional stability of problem behavior exposed to psychotropic medications.

Psychopharmacological and behavioral interventions are often combined in the treatment of problem behavior in people with intellectual and developmental disability (IDD). However, little is known about the interaction between medication pharmacodynamics and behavior function. A better understanding of these mechanisms could serve as the conceptual foundation for combined interventions. The current analysis is a systematic replication of Valdovinos et al. (2009). We conducted continuous functional analyses within analogue reversal and parametric analyses monitoring the impact of various dosages of primarily antipsychotic medications on problem behavior and its function. Four individuals with IDD and problem behavior who were also receiving psychotropic medications participated. Medication adjustments produced small to negligible decreases in problem behavior, and behavior function remained largely unchanged through the 14 medication adjustments evaluated. The continuous functional analysis helped to identify what could be delayed medication effects on problem behavior. The clinical and methodological implications of this replication are discussed.

Stem Cell-Derived Insulin-Producing Cells in 3D Engineered Tissue in a Perfusion Flow Bioreactor.

To circumvent the lack of donor pancreas, insulin-producing cells (IPCs) derived from pluripotent stem cells emerged as a viable cell source for the treatment of type 1 diabetes. While it has been shown that IPCs can be derived from pluripotent stem cells using various protocols, the long-term viability and functional stability of IPCs in vitro remains a challenge. Thus, the principles of three-dimensional (3D) tissue engineering and a perfusion flow bioreactor were used in this study to establish 3D microenvironment suitable for long-term in vitro culture of IPCs-derived from mouse embryonic stem cells. It was observed that in static 3D culture of IPCs, the viability decreased gradually with longer time in culture. However, when a low flow (0.02 mL/min) was continuously applied to 3D IPC containing tissues, enhanced survival and function of IPCs were demonstrated. IPCs cultured under low flow exhibited a significantly enhanced glucose responsiveness and upregulation of Ins1 compared to that of static culture. In summary, this study demonstrates the feasibility and benefits of 3D engineered tissue environment combined with perfusion flow in vitro for culturing stem cell-derived IPCs. Impact statement This in vitro three-dimensional tissue system combined with the flow can be used to better understand the role of biophysical cues that facilitates improved function and maturation of stem cell-derived insulin-producing cells, which can ultimately advance the field of pancreatic tissue engineering as well as in diabetes treatment.

Serum-Free Production of Three-Dimensional Hepatospheres from Pluripotent Stem Cells.

Developing renewable human liver tissue from stem cells has been pursued as a potential source of biological material for pharmaceutical and clinical endeavors. At present, two-dimensional differentiation procedures deliver tissue lacking long-term phenotypic and functional stability. Efforts to overcome these limiting factors have led to the development of protocols to generate three-dimensional cellular aggregates. Here we describe a methodology to generate 3D hepatospheres from human pluripotent stem cells using defined and commercially available reagents.

Rapid prototyping of soft bioelectronic implants for use as neuromuscular interfaces.

Neuromuscular interfaces are required to translate bioelectronic technologies for application in clinical medicine. Here, by leveraging the robotically controlled ink-jet deposition of low-viscosity conductive inks, extrusion of insulating silicone pastes and in situ activation of electrode surfaces via cold-air plasma, we show that soft biocompatible materials can be rapidly printed for the on-demand prototyping of customized electrode arrays well adjusted to specific anatomical environments, functions and experimental models. We also show, with the monitoring and activation of neuronal pathways in the brain, spinal cord and neuromuscular system of cats, rats and zebrafish, that the printed bioelectronic interfaces allow for long-term integration and functional stability. This technology might enable personalized bioelectronics for neuroprosthetic applications.

Treated dentin matrix‐based scaffolds carrying TGF-β1/BMP4 for functional bio-root regeneration

Biomaterial scaffold-based bioengineered tooth root (bio-root) has been proven to be a prospective tool for the treatment of tooth loss. However, while emulating the mechanical integrity of native tooth root, the regenerated bio-root still has limited capacity to achieve long-term functional stability because of lacking the effective cervical seal. Enlightened by physiological cues from cervical seal development and recovery of native tooth, this study reports a bioinspired approach as incorporation of two pivotal odontogenic growth factors (TGF-β1 and BMP4) into biomaterial scaffold (treated dentin matrix, TDM) embodying a spatial interface gradient for functional enthesis formation to promote functional bio-root regeneration. The biological characteristics of dental follicle stem cells (DFSCs) induced by TGF-β1/BMP4 were studied by relevant gene and protein expressions in vitro as well as ectopic subcutaneous transplantation and orthotopic jaw bone implantation in vivo. We further fabricated artificial crown-TDM/TGF-β1/BMP4/DFSCs in beagle to verify the potential occlusional function of regenerated bio-root. Notably, TGF-β1/BMP4 synergistically activated proliferation, migration and osteoinductivity related to the enthesis differentiation of DFSCs as increasing expressions of Periostin, BSP, OPN, ALP, Vinculin, and Paxillin and ascending numbers of migrated cells. The TDM/TGF-β1/BMP4/DFSCs composites imparted the uniform and persistent inductive interface for neovascularization and canonical enthesis regeneration. During more than 5 months follow-up in beagle model, the effectively functional bio-roots were distinguished by outstanding biomechanical properties and healthy gingiva similar to native teeth. This notion of integrating TGF-β1/BMP4 with TDM and DFSCs provides an alternative strategy for biomimetic bio-root regeneration and other interface tissue engineering.

Facial cortical bone regeneration post-extraction in non-grafted sockets allows for early implant placement and long-term functional stability

ObjectiveTo evaluate posterior implant placement feasibility shortly after tooth extraction in non-grafted sockets with and without dehiscence at the time of extraction. DesignNinety-five patients requiring posterior extractions entered this cross-sectional study. They were divided in three groups after extraction: G1 without dehiscence, G2 with dehiscence ≤5 and G3 > 5 mm. CBCT were taken prior to implant placement at an average of 12-weeks post-extraction to evaluate the need for grafting, cortical bone formation and bucco-lingual width (BLW). Actual BLW (n = 60) were compared to minimum expected BLW in 3 scenarios of BLW thickness averaging 6.4–7.4–8.4 mm. Peri-implant tissues were assessed for pocket formation and inflammation following established success criteria. ResultsNew cortical bone formation and sufficient BLW made implant placement feasible in sites with and without dehiscence at the time of extraction after an average healing time of 11.9 ± 2.4weeks (range: 8–18). Total average CBCT BLW was 10.1 ± 1.6 mm. All groups had a significantly higher BLW, than scenarios 1–3 (p < 0.0001). Molars were 20 times more likely than premolars to heal with BLW>10 mm (OR = 20; RR = 4.2; CI95 %: 5.3–74.2; p < 0.0001). Dehiscence sockets were 1.5 times more likely than non-dehiscenced sockets to present BLW ≤ 10 mm (OR = 1.5; RR = 0.6; CI95 %:0.9–2.5; p = 0.08). A band of keratinized tissue was present in all implants and success rates were 100 % at an average follow-up of 51.0 ± 23.4 months. ConclusionImplant placement is feasible without socket grafting shortly after tooth extraction. Non-grafted sockets present a significant osteogenic potential. Dehiscence sockets are likely to self-repair by forming a new cortical plate. The unassisted regenerated intra-socket bone allows for functional implant stability long-term.

Ultrathin, long-term stable, solid-state reference electrode enabled by enhanced interfacial adhesion and conformal coating of AgCl

Continuous biochemical monitoring with a flexible electrochemical sensor offers a new wearable electronic system that can measure real-time voltage and current signals. The signal quality is determined by long-term stability of a silver/silver chloride reference electrode (Ag/AgCl RE). However, it is very challenging for any solid-state electrode to have a long-term stable operation. Even though new membrane technologies have improved the voltage stability, the existing thin film Ag/AgCl REs have limitations of insufficient film adhesion and structural instability. Here, this paper introduces an ultrathin, all-solid-state RE that demonstrates a long-term functional stability for more than two weeks via enhanced interfacial adhesion and conformal coating of AgCl. An optimization of chlorination factors allows a highly uniform, 800 nm-thick RE surface. The voltage response of the sensor in a saline solution shows a change of 0.09 mV/h for 18 days with a quasi-stable behavior, capturing the potential as an amperometric biosensor. Moreover, the characterization with an enzymatic working electrode verifies that two-electrode system using the thin-film RE has a sensitivity (S = 606 nA·mmol−1. cm−2), compatible to that with a commercial RE (S = 532 nA·mmol−1. cm−2). Collectively, this work provides a comprehensive study of materials and surface functionalization of all-solid-state REs for thin-film biosensors, which will pave the way for long-term usable wearable biosystems.