Development of liposome/water partition coefficients predictive models for neutral and ionogenic organic chemicals.

Membrane/water partition coefficient (Km/w) is a vital parameter used to characterize the membrane permeability of compounds. Considering the Km/w value is difficult to observe experimentally for real biological membranes, liposome/water partition coefficient (Klip/w) is employed to approximate Km/w. Here, quantitative structure property relationship (QSPR) models for logKlip/w of the neutral organic chemicals and the neutral form of ionogenic organic chemicals (IOCs) (logKlip/w-neutral), ionic form of IOCs (logKlip/w-ionic), the speciation-corrected liposome-water distribution ratios at a pH = 7.40 (logDlip/w-(pH=7.40)) were developed. In the modeling, two modeling methods (multiple linear regressions (MLR) and k-nearest neighbor (kNN)) were used. The predictive variables employed here could be calculated from the molecular structure directly. For logKlip/w-neutral and logDlip/w-(pH=7.40), the logKOW and logDOW-based, non-logKOW and non-logDOW-based kNN-QSPR and MLR-QSPR models were developed, respectively. The evaluation results implied that the predictive performance of kNN-QSPR models is better than that of MLR-QSPR models. For logKlip/w-ionic, only one acceptable MLR-QSPR model was developed for cation and anion, respectively. The model quality of the derived models was evaluated following the OECD QSPR models validation guideline. The determination coefficient (R2), leave-one-out cross validation Q2 (Q2LOO) and bootstrapping coefficient (Q2BOOT), the external validation coefficient (Q2EXT) of all the models met the acceptable criteria (Q2 > 0.600, R2 > 0.700); while the root-mean-square error (RMSE) range from 0.351 to 0.857. All the results implied that the models had good goodness-of-fit, robustness and predictive ability. Therefore, the developed models could be used to fill the data gap for substances within the applicability domain on their missing logKlip/w-neutral, logKlip/w-ionic, logDlip/w-(pH=7.40) values.

Development of a clinical diagnostic model for Bell's palsy in patients with facial muscle weakness.

Early diagnosis of Bell's palsy is crucial for effective patient management in primary care settings. This study aimed to develop a simplified diagnostic tool to enhance the accuracy of identifying Bell's palsy among patients with facial muscle weakness. Data from 240 patients were analyzed using seven potential clinical evaluation indicators. Two diagnostic benchmarks were established: one based on clinical assessment and the other incorporating magnetic resonance imaging (MRI) findings. A multivariate logistic regression model was developed based on these benchmarks, resulting in the construction of a predictive tool evaluated through latent class models. Both models retained four key clinical indicators: absence of forehead wrinkles, accumulation of food and saliva inside the mouth on the affected side, presence of vesicular rash in the ear or pharynx, and lack of pain or symptoms associated with tick exposure, rash, or joint pain. The first model demonstrated excellent discriminative ability (area under the curve [AUC] = 0.96, 95% confidence interval [CI] 0.94 - 0.99) and calibration (P < 0.001), while the second model also showed good performance (AUC = 0.88, 95% CI 0.83 - 0.92) and calibration (P = 0.005). Bootstrap validation indicated no significant overfitting. The latent class defined by the first model significantly aligned with the clinical diagnosis group, while the second model showed lower consistency.

Synthesis and Biomedical Applications of DNA Hydrogel.

Deoxyribonucleic acid (DNA), as a natural polymer material, carries almost all the genetic information and is recognized as one of the most intelligent natural polymers. In the past 20 years, there have been many exciting advances in the synthesis of hydrogels using DNA as the main backbone or cross-linking agent. Different methods, such as physical entanglement and chemical cross-linking, have been developed to perform the gelation of DNA hydrogels. The good designability, biocompatibility, designable responsiveness, biodegradability and mechanical strength provided by DNA building blocks facilitate the application of DNA hydrogels in cytoscaffolds, drug delivery systems, immunotherapeutic carriers, biosensors and nanozyme-protected scaffolds. This review provides an overview of the main classification and synthesis methods of DNA hydrogels and highlights the application of DNA hydrogel in biomedical fields. It aims to give readers a better understanding of DNA hydrogels and development trends.

Chitosan-poloxamer-based thermosensitive hydrogels containing zinc gluconate/recombinant human epidermal growth factor benefit for antibacterial and wound healing.

Chitosan/poloxamer-based thermosensitive hydrogels containing zinc gluconate/recombinant human epidermal growth factor (ZnG/rhEGF@Chit/Polo) were developed as a convenient, safe and effective dressing for skin wound treatment. Their fabrication procedure and characterization were reported, and their morphology was examined by a scanning electron microscope. Antibacterial and biofilms activities were evaluated by in vitro tests to reveal the inhibitory effects and scavenging activity on the biofilms of Staphylococcus aureus and Pseudomonas aeruginosa. ZnG/rhEGF@Chit/Polo was also investigated as a potential therapeutic agent for wound healing therapy. In vivo wound healing studies on rats for 21 days proves that ZnG/rhEGF@Chit/Polo supplements the requisite Zn2+ and rhEGF for wound healing to promote the vascular remodeling and collagen deposition, facilitate fibrogenesis, and reduce the level of interleukin 6 for wound basement repair, and thus is a good wound therapy.

Toll­like receptor 4 activates the NLRP3 inflammasome pathway and periodontal inflammaging by inhibiting Bmi­1 expression.

Overproduction of pro­inflammatory cytokines in the aged, which is called inflammaging, leads to the deterioration of periodontitis. Toll­like receptor 4 (TLR4) plays a role in the regulation of cellular senescence, and its expression increases with age. However, there has been limited research into the molecular mechanisms underlying the onset of periodontal inflammaging, and the interplay between TLR4 and inflammaging. In the present study, wild­type and TLR4 gene knockout mice were used to investigate the activation of the TLR4 pathway in mouse periodontitis and the expression of the nucleotide­binding and oligomerization domain­like receptor 3 (NLRP3) inflammasome, an upstream immune checkpoint during the development of inflammaging. Activation of TLR4 in a mouse model of periodontitis enhanced the expression of a senescence­associated secretory phenotype (SASP), which boosted the inflammaging process. Conversely, TLR4 activation downregulated the expression of B cell­specific Moloney murine leukemia virus integration site 1 (Bmi­1) and promoted the priming of NLRP3 inflammasome, both of which are regulators of SASP. Treating gingival fibroblasts with Bmi­1 inhibitor PTC209, it was demonstrated that TLR4 activated the NLRP3 pathway and the inflammaging process by suppressing Bmi­1. In addition, there was a significant reduction in the expression of Bmi­1 expression in the gingiva of patients with periodontitis compared with healthy controls. In conclusion, the present study demonstrated that TLR4 acted by inhibiting Bmi­1 to enhance the NLRP3 pathway and SASP factors. This cascade of reactions may contribute to the senescence of the periodontium.

Tetrahedral Framework Nucleic Acid Promotes the Treatment of Bisphosphonate-Related Osteonecrosis of the Jaws by Promoting Angiogenesis and M2 Polarization.

Bisphosphonates are often used to treat osteoporosis, malignant bone metastases, and hypercalcemia. However, it can cause serious adverse reactions, bisphosphonate-related osteonecrosis of the jaw (BRONJ), which seriously affects the quality of life of patients. At present, the treatment of BRONJ is still difficult to reach an agreement, and there is no effective treatment. Therefore, it is very important to find effective treatments. Many studies have shown that the occurrence of BRONJ may be due to unbalanced bone turnover, anti-angiogenesis, bacterial infection, direct tissue toxicity, and abnormal immune function. The previous research results show that tetrahedral framework nucleic acids (tFNAs), a new type of nanomaterial, can promote various biological activities of cells, such as cell proliferation, migration, anti-inflammation and anti-oxidation, and angiogenesis. Therefore, we intend to explore the potential of tFNAs in the treatment of BRONJ through this study. The results show that tFNAs can promote the treatment of BRONJ by promoting angiogenesis and promoting M2 polarization in macrophages and inhibiting M1 polarization both in vitro and in vivo. These results provide a theoretical basis for the application of tFNAs in the treatment of BRONJ and also provide new ideas and methods for the treatment of other diseases based on ischemia and immune disorders.

Design, fabrication and applications of tetrahedral DNA nanostructure-based multifunctional complexes in drug delivery and biomedical treatment.

Although organic nanomaterials and inorganic nanoparticles possess inherent flexibility, facilitating functional modification, increased intracellular uptake and controllable drug release, their underlying cytotoxicity and lack of specificity still cause safety concerns. Owing to their merits, which include natural biocompatibility, structural stability, unsurpassed programmability, ease of internalization and editable functionality, tetrahedral DNA nanostructures show promising potential as an alternative vehicle for drug delivery and biomedical treatment. Here, we describe the design, fabrication, purification, characterization and potential biomedical applications of a self-assembling tetrahedral DNA nanostructure (TDN)-based multifunctional delivery system. First, relying on Watson-Crick base pairing, four single DNA strands form a simple and typical pyramid structure via one hybridization step. Then, the protocol details four different modification approaches, including replacing a short sequence of a single DNA strand by an antisense peptide nucleic acid, appending an aptamer to the vertex, direct incubation with small-molecular-weight drugs such as paclitaxel and wogonin and coating with protective agents such as cationic polymers. These modified TDN-based complexes promote the intracellular uptake and biostability of the delivered molecules, and show promise in the fields of targeted therapy, antibacterial and anticancer treatment and tissue regeneration. The entire duration of assembly and characterization depends on the cargo type and modification method, which takes from 2 h to 3 d.

Poloxamer modified florfenicol instant microparticles for improved oral bioavailability.

Surfactants can improve the hydrophobicity of poorly water-soluble drugs and increase the stability of microparticles by reducing surface tension. This study describes that surfactant-engineered florfenicol instant microparticles (FIMs) increase bioavailability through a micellar solubilization mechanism. The FIMs were prepared by a modified emulsification method, and the optimal prescription was obtained by a combination of single factor investigation and response surface methodology. The microparticles prepared in this study reduce the polymer materials while increasing the drug content. FIM has a smaller particle size and modification of poloxamer, resulting in better solubility and higher bioavailability. The in vitro solubility of FIM is 1.43 times higher than that of the bulk drug, and the dissolution equilibrium can be achieved in 10 minutes. Compared with florfenicol, FIM showed a decrease in Tmax in the plasma concentration curve, with a peak concentration of 1.43 times and an area of 1.41 times. Considering the advantages of in vitro/in vivo performance and ease of preparation, FIMs may have great application prospects in pharmacy research.

PEGylated Protamine-Based Adsorbing Improves the Biological Properties and Stability of Tetrahedral Framework Nucleic Acids.

Recently, many researchers have reported that DNA nanostructures, such as tetrahedral framework nucleic acids (tFNAs), have great potential to be useful tools in clinical and laboratory applications due to their programmable shapes, functional sites, and biological responses. However, finite endocytosis and stability in cells and body fluids compromise the functions of DNA nanostructures as a result of various adverse factors. In this study, we successfully synthesized PEGylated protamine, and tFNAs were adsorbed to it in a proper ratio of nitrogen in protamine to phosphorus in tFNAs (N/P ratio) as the functional complex. Furthermore, we demonstrated that PEGylated protamine-adsorbed tFNAs show a more prominent positive effect on cell viability and proliferation than naked tFNAs do. An increase in endocytosis can be observed in three different tissue-derived cells with the PEG-protamine-tFNA (PPT) complex. The increased endocytic ability is mediated by multiple pathways; moreover, the stimulatory effect of the PPT complex on the endocytic ability is dramatically blocked by the inhibition of the caveola-dependent pathway. Consistently, when tFNAs are stabilized by PEGylated protamine, they often tend to escape from lysosomes and survive for a longer period in biological fluids rather than being rapidly eliminated from the kidneys. The in vitro and in vivo results of our study demonstrate that the PPT complex method is a feasible, potent, and low-cost strategy that improves tFNA biocompatibility, stability, and internalization. This study provides evidence supporting the possibility of implementing PPTs for use in drug delivery, bioimaging, and gene transfection in the future.

Physical Cues Drive Chondrogenic Differentiation.

BACKGROUND: Cellular differentiation occurs in a complicated microenvironment containing multiple components including soluble factors and physical cues. In addition to biochemical composition, physical cues are also crucial in determining cellular behaviors. OBJECTIVE: To better understand the interaction between physical signals and cells, we discuss the effects of physical cues on cellular behaviors, especially chondrogenic differentiation in vitro. Furthermore, the mechanisms by which these physical signals are transmitted from the extracellular matrix into the cell are also considered. RESULTS: Physical cues can dramatically regulate specific cellular functions in cartilage tissue engineering. Integrin and FAs act as mechano-sensors to transmit physical cues from the ECM into cytoskeleton- signaling network. Meanwhile, the RhoA/ROCK signaling pathway and YAP/TAZ play indispensable roles in cell and ECM linkages. CONCLUSION: The investigation of physical cues clarifies cellular behaviors. This information can be applied to tissue engineering scaffold and biological material production in the future.

Stiffness regulates the proliferation and osteogenic/odontogenic differentiation of human dental pulp stem cells via the WNT signalling pathway.

OBJECTIVES: Researches showed that stiffness of the extracellular matrix can affect the differentiation of many stem cells. Dental pulp stem cells (DPSCs) are a promising type of adult stem cell. However, we know little about whether and how the behaviour of DPSCs is influenced by stiffness. MATERIALS AND METHODS: We carried out a study that cultured DPSCs on tunable elasticity polydimethylsiloxane substrates to investigate the influence on morphology, proliferation, osteogenic/odontogenic differentiation and its possible mechanism. RESULTS: Soft substrates changed the cell morphology and inhibited the proliferation of DPSCs. Expression of markers related to osteogenic/odontogenic differentiation was significantly increased as the substrate stiffness increased, including ALP (alkaline phosphatase), OCN (osteocalcin), OPN (osteopontin), RUNX-2 (runt-related transcription factor-2), BMP-2 (bone morphogenetic protein-2), DSPP (dentin sialophosphoprotein) and DMP-1 (dentin matrix protein-1). Mechanical properties promote the function of DPSCs related to the Wnt signalling pathway. CONCLUSIONS: Our results showed that mechanical factors can regulate the proliferation and differentiation of DPSCs via the WNT signalling pathway. This provides theoretical basis to optimize dental or bone tissue regeneration through increasing stiffness of extracelluar matrix.

Electrospun Fibers for Cartilage Tissue Regeneration.

BACKGROUND: Cartilage injury has always been puzzled for clinicians. The treatments used clinically for cartilage injury usually bring about fibrocartilage. The emergence of tissue engineering lights up the hope of cartilage repair. OBJECTIVE: This review will sum up the existing learnings about electrospun fibers, revolving about the electrospinning materials, micromorphology, improvements and electrospun technologies newly developed in cartilage repair and regeneration. RESULTS: Electrospun fibers as scaffolds for cartilage regeneration have been one of researching hotspots for years. The studies about new electrospun materials and new electrospinning technologies greatly promoted the development of this field. CONCLUSION: Electrospun fibers have showed great potential in cartilage regeneration. But there is still a long way to go before clinical application. The material embellishment and structure imitation should be highlighted in future.

Modulation of chondrocyte motility by tetrahedral DNA nanostructures.

OBJECTIVES: Contemporarily, a highly increasing attention was paid to nanoconstructs, particularly DNA nanostructures possessing precise organization, functional manipulation, biocompatibility and biodegradability. Amongst these DNA nanomaterials, tetrahedral DNA nanostructures (TDNs) are a significantly ideal bionanomaterials with focusing on the property that can be internalized into cytoplasm in the absence of transfection. Therefore, the focus of this study was on investigating the influence of TDNs on the chondrocytes locomotion. MATERIALS AND METHODS: Tetrahedral DNA nanostructures was confirmed by 6% polyacrylamide gel electrophoresis (PAGE) and dynamic light scattering (DLS). Subsequently, the effect of TDNs on chondrocyte locomotion was investigated by real-time cell analysis (RTCA) and wound healing assay. The variation of relevant genes and proteins was detected by quantitative polymerase chain reaction (qPCR), western blotting and immunofluorescence respectively. RESULTS: We demonstrated that tetrahedral DNA nanostructures have positive influence on chondrocytes locomotion and promoted the expression of RhoA, ROCK2 and vinculin. Additionally, upon exposure to TDNs with the concentration of 250 nmol L-1 , the chondrocytes were showed the highest motility via both RTCA and wound healing assay. Meanwhile, the mRNA and protein expression of RhoA, ROCK2 and vinculin were also significantly enhanced with the same concentration. CONCLUSIONS: It can be concluded that the TDNs with the optimal concentration of 250 nmol L-1 could extremely promoted the chondrocytes locomotion through facilitating the expression of RhoA, ROCK2 and vinculin. These results seemed to reveal that this special three-dimensional DNA tetrahedral nanostructures may be applied to cartilage repair and treatment in the future.

Fabrication of Calcium Phosphate Microflowers and Their Extended Application in Bone Regeneration.

The structure of materials is known to play an important role in material function. Nowadays, flowerlike structures have gained attention for studies not only in analytical chemistry, but also in biomaterial design. In this study, flowerlike structures were applied in bone regeneration in the form of calcium phosphate microflowers. The material was synthesized by a simple and environmentally friendly method. We characterized the structure and properties of the microflower using various methods. Cytotoxicity and osteogenesis-related gene regulations of the microflower were investigated in vitro. Cell uptake was observed by immunofluorescence. Rat calvarial critical-size defect models were successfully established to further confirm the enhanced bone regeneration ability of this material. We expect that this novel study will be of practical importance for the extended application of flowerlike materials and will provide new insights into the optimization of the morphology of calcium phosphate materials.

Injectable and thermosensitive TGF-ß1-loaded PCEC hydrogel system for in vivo cartilage repair.

Chondral defects pose a great challenge for clinicians to manage owing to the limited capacity for self-healing. Various traditional approaches have been adopted for the repair of these defects with unsatisfactory results. Cartilage tissue engineering techniques have emerged as promising strategies to enhance regeneration and overcome these traditional shortcomings. The cell-homing based technique is considered the most promising owing to its unique advantages. Thermosensitive hydrogels have been applied as scaffolds for biomedical applications with smart sol-gel response for altering environmental temperature. Transforming growth factor (TGF)-ß1 is considered to be capable of promoting chondrogenesis. In this study, a novel TGF-ß1-loaded poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCEC) hydrogel was fabricated using simple procedures. Hydrogel characterization, rheological testing, component analysis, and assessment of sol-gel transition, in vitro degradation, and TGF-ß1 release confirmed that this material possesses a porous microstructure with favorable injectability and sustained drug release. Full-thickness cartilage defects were induced on rat knees for in vivo cartilage repair for eight weeks. Micro-CT and histological evaluation provided further evidence of the optimal capacity of this novel hydrogel for cartilage regeneration with respect to that of other methods. Moreover, our results demonstrated that the cell-free hydrogel is thermosensitive, injectable, biodegradable, and capable of in vivo cartilage repair and possesses high potential and benefits for acellular cartilage tissue engineering and clinical application in the future.

Electrospun Poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/Graphene Oxide Scaffold: Enhanced Properties and Promoted in Vivo Bone Repair in Rats.

Bone tissue engineering emerges as an advantageous technique to achieve tissue regeneration. Its scaffolds must present excellent biomechanical properties, where bare polymers poorly perform. Development of new biomaterials with high osteogenic capacity is urgently pursued. In this study, an electrospun poly(3-hydroxybutyrate-co-4-hydroxybutyrate)/graphene oxide (P34HB/GO) nanofibrous scaffold is successfully fabricated and characterized. The effects of GO amount on scaffold morphology, biomechanical properties, and cellular behaviors are investigated. GO reduces the fiber diameter and enhances porosity, hydrophilicity, mechanical properties, cellular performance, and osteogenic differentiation of scaffolds. P34HB/GO triumphs over P34HB in in vivo bone regeneration in critical-sized calvarial defect of rats. We believe that this study is the first to evaluate the capability of in vivo bone repair of electrospun P34HB/GO scaffold. With facile fabrication process, favorable porous structures, enhanced biomechanical properties, and fast osteogenic capability, P34HB/GO scaffold holds practical potentials for bone tissue engineering application.

PCL-PEG-PCL film promotes cartilage regeneration in vivo.

OBJECTIVE: Management of chondral defects has long been a challenge due to poor self-healing capacity of articular cartilage. Many approaches, ranging from symptomatic treatment to structural cartilage regeneration, have obtained very limited satisfactory results. Cartilage tissue engineering, which involves optimized combination of novel scaffolds, cell sources and growth factors, has emerged as a promising strategy for cartilage regeneration and repair. In this study, the aim was to investigate the role of poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL, PCEC) PCEC scaffold in cartilage repair. MATERIALS AND METHODS: First, PCEC film was fabricated, and its characteristics were tested using SEM and AFM. Cell (rASC - rat adipose-derived stem cells, and mASCs - green fluorescent mouse adipose-derived stem cells) morphologies on PCEC film were observed using SEM and fluorescence microscopy, after cell seeding. Tests of cell viability on PCEC film were conducted using the CCK-8 assay. Furthermore, full cartilage defects in rats were created, and PCEC films were implanted, to evaluate their healing effects, over 8 weeks. RESULTS: It was found that PCEC film, as a biomaterial implant, possessed good in vitro properties for cell adhesion, migration and proliferation. Importantly, in the in vivo experiment, PCEC film exhibited desirable healing outcomes. CONCLUSIONS: These results demonstrated that PCEC film was a good scaffold for cartilage tissue engineering for improving cell proliferation and adhesion and could lead to excellent repair of cartilage defects.