Formation of non-base-pairing DNA microgels using directed phase transition of amphiphilic monomers.

Programmability of DNA sequences enables the formation of synthetic DNA nanostructures and their macromolecular assemblies such as DNA hydrogels. The base pair-level interaction of DNA is a foundational and powerful mechanism to build DNA structures at the nanoscale; however, its temperature sensitivity and weak interaction force remain a barrier for the facile and scalable assembly of DNA structures toward higher-order structures. We conducted this study to provide an alternative, non-base-pairing approach to connect nanoscale DNA units to yield micrometer-sized gels based on the sequential phase transition of amphiphilic unit structures. Strong electrostatic interactions between DNA nanostructures and polyelectrolyte spermines led to the formation of giant phase-separated aggregates of monomer units. Gelation could be initiated by the addition of NaCl, which weakened the electrostatic DNA-spermine interaction while attractive interactions between cholesterols created stable networks by crosslinking DNA monomers. In contrast to the conventional DNA gelation techniques, our system used solid aggregates as a precursor for DNA microgels. Therefore, in situ gelation could be achieved by depositing aggregates on the desired substrate and subsequently initiating a phase transition. Our approach can expand the utility and functionality of DNA hydrogels by using more complex nucleic acid assemblies as unit structures and combining the technique with top-down microfabrication methods.

Injectable Conductive Hydrogels with Tunable Degradability as Novel Implantable Bioelectrodes.

Bioelectrodes have been developed to efficiently mediate electrical signals of biological systems as stimulators and recording devices. Recently, conductive hydrogels have garnered great attention as emerging materials for bioelectrode applications because they can permit intimate/conformal contact with living tissues and tissue-like softness. However, administration and control over the in vivo lifetime of bioelectrodes remain challenges. Here, injectable conductive hydrogels (ICHs) with tunable degradability as implantable bioelectrodes are developed. ICHs were constructed via thiol-ene reactions using poly(ethylene glycol)-tetrathiol and thiol-functionalized reduced graphene oxide with either hydrolyzable poly(ethylene glycol)-diacrylate or stable poly(ethylene glycol)-dimaleimide, the resultant hydrogels of which are degradable and nondegradable, respectively. The ICH electrodes had conductivities of 21-22 mS cm-1 and Young's moduli of 15-17 kPa, and showed excellent cell and tissue compatibility. The hydrolyzable conductive hydrogels disappeared 3 days after in vivo administration, while the stable conductive hydrogels maintained their shapes for up to 7 days. Our proof-of-concept studies reveal that electromyography signals with significantly improved sensitivity from rats could be obtained from the injected ICH electrodes compared to skin electrodes and injected nonconductive hydrogel electrodes. The ICHs, offering convenience in use, controllable degradation and excellent signal transmission, will have great potential to develop various bioelectronics devices.

The use of mouthguards and related factors among basketball players in Indonesia.

BACKGROUND: Basketball is a sport with a higher injury rate. Regardless, few basketball players use mouthguards, which predisposes them to injuries. The use of mouthguards (UoM) could be related to several factors. This study aims to identify factors associated with UoM and to construct a model from the factors among basketball players in Indonesia. METHODS: Through convenience sampling, a total of 286 among basketball players in Indonesia was included in this cross-sectional study. These participants filled out online a modified questionnaires regarding demographic and several factors related to UoM. The data was analyzed using chi-square test, independent-sample t-test, binary logistic regression, and structural equation modeling (SEM). RESULTS: There were 286 players. 127 of them were males and 159 were females. Of them, 86 (30.1%) used mouthguards. Age, duration (in year), and weekly practicing basketball (in hour) were all significantly different between mouthguards users and non-users with (p = 0.005, p = 0.036 and p = 0.035), respectively. The UoM was significantly associated with level of awareness, injury experience, social support, and oral health professional (OHP) support with (p = 0.002, p < 0.001, p < 0.001 and p < 0.001), respectively. This result was also supported by a variety of variables' ORs, which range from 1.28 to 5.97. The coefficient of determination (R2) was 0.27. CONCLUSIONS: The UoM among basketball players in Indonesia was related to several factors, including the level of knowledge, level of awareness, duration of basketball career, injury experiences, social support, and oral health professionals' support which was constructed to propose a model. The model could explain 27% of the relationship between variables and UoM among Indonesian basketball players. This model will be useful for more comprehensive initiatives to promote oral health. It might be applicable for other countries as well as other sports communities / physical activities.

Vimentin Targeted Nano-gene Carrier for Treatment of Renal Diseases.

BACKGROUND: Chronic kidney disease (CKD) is a global health problem, and there is no permanent treatment for reversing kidney failure; thus, early diagnosis and effective treatment are required. Gene therapy has outstanding potential; however, the lack of safe gene delivery vectors, a reasonable transfection rate, and kidney targeting ability limit its application. Nanoparticles can offer innovative ways to diagnose and treat kidney diseases as they facilitate targetability and therapeutic efficacy. METHODS: Herein, we developed a proximal renal tubule-targeting gene delivery system based on alternative copolymer (PS) of sorbitol and polyethyleneimine (PEI), modified with vimentin-specific chitobionic acid (CA), producing PS-conjugated CA (PSC) for targeting toward vimentin-expressing cells in the kidneys. In vitro studies were used to determine cell viability, transfection efficiency, serum influence, and specific uptake in the human proximal renal tubular epithelial cell line (HK-2). Finally, the targeting efficiency of the prepared PSC gene carriers was checked in a murine model of Alport syndrome. RESULTS: Our results suggested that the prepared polyplex showed low cytotoxicity, enhanced transfection efficiency, specific uptake toward HK-2 cells, and excellent targeting efficiency toward the kidneys. CONCLUSION: Collectively, from these results it can be inferred that the PSC can be further evaluated as a potential gene carrier for the kidney-targeted delivery of therapeutic genes for treating diseases.

Aberrant Mitochondrial Dynamics and Exacerbated Response to Neuroinflammation in a Novel Mouse Model of CMT2A.

Charcot-Marie-Tooth disease type 2A (CMT2A) is the most common hereditary axonal neuropathy caused by mutations in MFN2 encoding Mitofusin-2, a multifunctional protein located in the outer mitochondrial membrane. In order to study the effects of a novel MFN2K357T mutation associated with early onset, autosomal dominant severe CMT2A, we generated a knock-in mouse model. While Mfn2K357T/K357T mouse pups were postnatally lethal, Mfn2+/K357T heterozygous mice were asymptomatic and had no histopathological changes in their sciatic nerves up to 10 months of age. However, immunofluorescence analysis of Mfn2+/K357T mice revealed aberrant mitochondrial clustering in the sciatic nerves from 6 months of age, in optic nerves from 8 months, and in lumbar spinal cord white matter at 10 months, along with microglia activation. Ultrastructural analyses confirmed dysmorphic mitochondrial aggregates in sciatic and optic nerves. After exposure of 6-month-old mice to lipopolysaccharide, Mfn2+/K357T mice displayed a higher immune response, a more severe motor impairment, and increased CNS inflammation, microglia activation, and macrophage infiltrates. Overall, ubiquitous Mfn2K357T expression renders the CNS and peripheral nerves of Mfn2+/K357T mice more susceptible to mitochondrial clustering, and augments their response to inflammation, modeling some cellular mechanisms that may be relevant for the development of neuropathy in patients with CMT2A.

Histone Lys demethylase KDM3C demonstrates anti-inflammatory effects by suppressing NF-κB signaling and osteoclastogenesis.

Histone Lys-specific demethylases (KDMs) play a key role in many biological processes through epigenetic mechanisms. However, the role of KDMs in inflammatory responses to oral bacterial infection is poorly understood. Here, we show a novel regulatory role of KDM3C in inflammatory responses to oral bacterial infection. KDM3C expression is transiently suppressed in human and mouse macrophages exposed to LPS from Porphyromonas gingivalis (Pg LPS). Loss of KDM3C in both human and mouse macrophages led to notable induction of proinflammatory cytokines in response to Pg LPS stimulation. Also, KDM3C depletion led to strong induction of p65 phosphorylation and accelerated nuclear translocation in cells exposed to Pg LPS. Kdm3C knockout (KO) in mice led to increased alveolar bone destruction upon induction of experimental periodontitis or pulp exposure compared with those of the wild-type (WT) littermates. The Kdm3C KO mice also revealed an increased number of osteoclasts juxtaposed to the bony lesions. We also confirmed enhanced osteoclastogenesis by bone marrow-derived macrophages isolated from the Kdm3C KO compared with the WT controls. These findings suggest an anti-inflammatory function of KDM3C in regulating the inflammatory responses against oral bacterial infection through suppression of NF-κB signaling and osteoclastogenesis.-Lee, J. Y., Mehrazarin, S., Alshaikh, A., Kim, S., Chen, W., Lux, R., Gwack, Y., Kim, R. H., Kang, M. K. Histone Lys demethylase KDM3C demonstrates anti-inflammatory effects by suppressing NF-κB signaling and osteoclastogenesis.

Hyaluronan-Stabilized Redox-Sensitive Nanoassembly for Chemo-Gene Therapy and Dual T1/T2 MR Imaging in Drug-Resistant Breast Cancer Cells.

Tailoring combinatorial therapies along with real-time monitoring strategies has been the major focus of overcoming multidrug resistance in cancer. However, attempting to develop a multifunctional nanoplatform in a single construct leads to compromising therapeutic outcomes. Herein, we developed a simple, theranostic nanoassembly containing a hyaluronic acid-stabilized redox-sensitive (HART) polyethylenimine polyplex composed of a doxorubicin (DOX) intercalated Bcl-2 shRNA encoded plasmid along with a green-synthesized hausmannite (Mn3O4) and hematite (Fe3O4) nanoparticle (GMF). The highly stable HART nanoassembly has enhanced CD44-mediated intracellular uptake along with hyaluronidase (hylase) and redox-responsive drug-gene release. With Bcl-2 gene silencing induced by the successful delivery of HART in multidrug-resistant MCF7 breast cancer cells, the synergistic cytotoxic effect of Bcl-2 silencing and DOX was achieved. In addition, the HART nanoassembly containing GMF exhibited excellent dual MRI contrast (T1/T2) by reducing artifact signals. Overall, the HART nanoassembly with its enhanced theranostic properties has the potential to improve the therapeutic efficacy in future preclinical and clinical trials.

Preparation of Radiation Cross-Linked Poly(Acrylic Acid) Hydrogel Containing Metronidazole with Enhanced Antibacterial Activity.

Metronidazole (MD) is known as a periodontitis medicine and has been widely used in antibiotics for resistance to anaerobic bacteria, periodontal disease, and other threats. To treat diseases, drug delivery carriers are needed with a high bioadhesive property and enhanced drug penetration. Poly (acrylic acid) (PAA) hydrogel films have a good bioadhesive property and are able to localize the absorption site and increase the drug residence time. In this study, we fabricated a MD loaded PAA hydrogel with different MD content (0.1, 0.25, 0.5, and 1 wt%) using varying doses (25, 50, and 75 kGy) and the radiation doses (25, 50, or 75 kGy) in a one-step gamma-ray irradiation process. The chemical and physical structure were determined through a Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy, gel content, and compressive strength. In addition, MD loaded PAA hydrogels were performed to MD release behaviors and cytotoxicity. Finally, we conducted antibacterial activity to demonstrate the prevention of growth of bacteria as a therapeutic dressing. The basic chemical structure analysis of MD was changed greatly at radiation doses of 50 and 75 kGy due to degradation by gamma-ray irradiation. However, when the absorbed dose was 25 kGy, the chemical structure analysis of MD did not change significantly, and the gel content and compressive strength of MD/PAA hydrogel were approximately 80% and 130 kPa, respectively. The MD/PAA hydrogels exhibited no cytotoxicity and good antibacterial activity against Escherichia coli, Staphylococcus aureus, and Streptococcus mutans. These results provide good evidence that MD/PAA hydrogel prepared by gamma-ray irradiation has potential as a competitive candidate for the therapeutic dressing.

The use of an interdental brush mitigates periodontal health inequalities: the Korean National Health and nutrition examination survey (KNHANES).

BACKGROUND: The purpose of this study was to evaluate the mitigating effect of the use of interdental brushes on periodontal health inequality. METHODS: This study was based on the data acquired in the Sixth Korea National Health and Nutrition Examination Survey (KNHANES VI; 2013-2015). A total of 17,583 participants (7,633 males and 9,950 females)) aged 19 years or older completed the KNHANES VI between 2013 and 2015. Multivariable logistic regression analysis was performed using socioeconomic characteristics (sex, age, level of education, individual income), personal health practice (smoking, toothbrushing, dental flossing, interdental brushing, dental clinic visiting), systematic medical factors (diabetes mellitus, hypercholesterolemia, hypertension, obesity) and the community periodontal index. We confirmed differences in the prevalence of periodontal disease with the use of an interdental brushes stratified according to individual income. RESULTS: Three logistic regression models adjusted for covariates hierarchically. In all models, individuals who used an interdental brush were not significantly different from individuals who did not use an interdental brush. The adjusted odds ratio (OR) for interdental brushing was 0.918 with a 95% confidence intervals (CIs) of 0.797-1.057. When periodontal disease was the outcome of the model, the lowest income group had 1.266 (95% CIs 1.066 to 1.502) times the odds of having periodontal disease than the highest income group. In interdental brush nonusers, the lowest income group had 1.276 (95% CI 1.061-1.533) times the odds of having periodontal diseases than the highest income group. However, in the interdental brush users, there were no significant differences in periodontal disease prevalence among income groups. CONCLUSIONS: The results suggest that the use of interdental brushes could alleviate periodontal health inequality.

Capmul MCM/Solutol HS15-Based Microemulsion for Enhanced Oral Bioavailability of Rebamipide.

Rebamipide (RBP) is a potent anti-ulcer and anti-oxidative agent, which is a BCS class IV drug with a low oral bioavailability of less than 10%. Thus, the systemic absorption of RBP into the blood circulation is an essential prerequisite for exerting its pharmacological activities after oral dosing. Herein, we report on microemulsion (ME) systems for the enhancement of oral RBP bioavailability. In this study, MEs consisting of Capmul MCM (oil), Solutol HS15 (surfactant), and ethanol (co-surfactant) were prepared by the construction of pseudo-ternary phase diagram. The RBP-loaded MEs had spherical nano-sized droplets with narrow size distribution and neutral zeta potential. Moreover, the prepared MEs significantly enhanced the dissolution and oral bioavailability of RBP with no discernible intestinal toxicity. These results suggest that the present ME system could be further developed as an alternative oral formulation for RBP.

Development of Houttuynia cordata Extract-Loaded Solid Lipid Nanoparticles for Oral Delivery: High Drug Loading Efficiency and Controlled Release.

Houttuynia cordata (H. cordata) has been used for diuresis and detoxification in folk medicine as well as a herbal medicine with antiviral and antibacterial activities. H. cordata extract-loaded solid lipid nanoparticles (H-SLNs) were prepared with various concentration of poloxamer 188 or poloxamer 407 by a hot homogenization and ultrasonication method. H-SLNs dispersion was freeze-dried with or without trehalose as a cryoprotectant. The physicochemical characteristics of H-SLNs were evaluated by dynamic laser scattering (DLS), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). Additionally, the in vitro release and in vitro cytotoxicity of H-SLNs were measured. Encapsulation efficiencies of H-SLNs (as quercitrin) were 92.9-95.9%. The SEM images of H-SLNs showed that H-SLNs have a spherical morphology. DSC and FT-IR showed that there were no interactions between ingredients. The increased extent of particle size of freeze-dried H-SLNs with trehalose was significantly lower than that of H-SLNs without trehalose. H-SLNs provided sustained release of quercitrin from H. cordata extracts. Cell viability of Caco-2 cells was over 70% according to the concentration of various formulation. Therefore, it was suggested that SLNs could be good carrier for administering H. cordata extracts.

Evaluation of the Effectiveness of Children's Dental Care Programs: A Retrospective Study.

This study aimed to evaluate the long-term impact of children's dental care programs on children and adolescents to reduce oral health inequalities. It measured and assessed the improvement effects of children's dental care programs on the oral health of children and adolescents as part of the efforts to decrease oral health disparities in this age group. It included 406 individuals who participated in student and children's dental care program between 2013 and 2019 at screening facilities in Gwangjin-gu, Seoul. A frequency analysis was conducted for demographic characteristics, and a binary logistic regression analysis was performed to identify factors influencing the prevalence of dental caries as the dependent variable. The data were analyzed using PASW Statistics with the statistical significance level set at α = 0.05. Regarding oral health status based on the frequency of participation in children's dental care program for children and adolescents, participants with seven or more sessions had lower prevalence rates of dental caries, malocclusion, and periodontal disease than those with only one session. Second, when comparing oral health status in children's dental care program between primary and adolescent age groups, individuals under continuous oral health care showed a decrease in permanent teeth affected by dental caries, dental caries prevalence, and malocclusion prevalence (excluding primary school age). Third, a binary logistic regression analysis revealed significant influences (p < 0.05) of the developmental stage and frequency of program participation on dental caries prevalence. Children's dental care programs are essential for alleviating oral health inequalities among children and adolescents and preventing oral diseases. Furthermore, the developmental stage of children and the frequency of program participation are crucial factors in preventing oral conditions, such as dental caries.

Enzymatically stable, non-cell adhesive, implantable polypyrrole/thiolated hyaluronic acid bioelectrodes for in vivo signal recording.

Implantable bioelectrodes have attracted significant attention for precise in vivo signal transduction with living systems. Conductive polymers, including polypyrrole (PPy), have been widely used as bioelectrodes due to their large surface areas, high charge injections, and versatilities for modification. Especially, several natural biopolymers, such as hyaluronic acid (HA), can be incorporated into conductive polymers to produce biomimetic electrodes with better biocompatibility. However, HA-incorporated PPy electrodes (PPy/HA) frequently lose their original performances after implantation in the body because of the deterioration of material properties, such as degradation of natural biopolymers in the electrode. Here, thiolated HA (HA-SH) was synthesized and introduced into PPy electrodes (PPy/HA-SH) to enhance the enzymatic stabilities of PPy electrodes against hyaluronidase (HAase) and endow these electrodes with robust resistances to non-specific cell adhesion, thereby enabling prolonged signal transmission. Unlike PPy/HA, PPy/HA-SH resisted cell adhesion even in the presence of HAase. Subcutaneous implantation studies revealed that PPy/HA-SH formed less fibrotic scar tissue and permitted more sensitive and stable signal recording for up to 15 days after implantation as compared to PPy/HA. These findings hold significance for the design and advancement of biocompatible implantable bioelectrodes for a wide range of applications, such as neural electrodes, cardiac pacemakers, and biosensors.

"Three-in-one": A Photoactivable Nanoplatform Evokes Anti-Immune Response by Inhibiting BRD4-cMYC-PDL1 Axis to Intensify Photo-Immunotherapy.

Combinatorial immuno-cancer therapy is recognized as a promising approach for efficiently treating malignant tumors. Yet, the development of multifunctional nanomedicine capable of precise tumor targeting, remote activation, and immune-regulating drug delivery remains a significant challenge. In this study, nanoparticles loaded with an immune checkpoint inhibitor (JQ-1) using polypyrrole/hyaluronic acid (PPyHA/JQ-1) are developed. These nanoparticles offer active tumor targeting, photothermal tumor ablation using near-infrared light, and laser-controlled JQ-1 release for efficient breast cancer treatment. When the molecular weight of HA varies (from 6.8 kDa to 3 MDa) in the PPyHA nanoparticles, it is found that the nanoparticles synthesized using 1 MDa HA, referred to as PPyHA (1 m), show the most suitable properties, including small hydrodynamic size, high surface HA contents, and colloidal stability. Upon 808 nm laser irradiation, PPyHA/JQ-1 elevates the temperature above 55 °C, which is sufficient for thermal ablation and active release of JQ-1 in the tumor microenvironment (TME). Notably, the controlled release of JQ-1 substantially inhibits the expression of cancer-promoting genes. Furthermore, PPyHA/JQ-1 effectively suppresses the expression of programmed cell death ligand 1 (PD-L1) and prolongs dendritic cell maturation and CD8+ T cell activation against the tumor both in vitro and in vivo. PPyHA/JQ-1 treatment simultaneously provides a significant tumor regression through photothermal therapy and immune checkpoint blockade, leading to a durable antitumor-immune response. Overall, "Three-in-one" immunotherapeutic photo-activable nanoparticles have the potential to be beneficial for a targeted combinatorial treatment approach for TNBC.

Tumor suppression effect of ultrasound-sensitive nanoparticles with focused ultrasound in a pancreas cancer xenograft model.

BACKGROUND: We investigated the tumor suppression effect of an ultrasound-sensitive doxorubicin-loaded liposome-based nanoparticle, IMP301, to enhance the synergistic effect with focused ultrasound (FUS) in an animal model of pancreatic cancer. METHODS: Thirty nude mice with xenografts of PANC-1 human pancreatic cancer cells were randomly and prospectively allocated to 6 different groups (5 per group) each for Study-1 (dose-response test) and Study-2 (synergistic effect test). Study-1 consisted of control, gemcitabine, Doxil with FUS, and three different doses of IMP301 (2, 4, 6 mg/kg) with FUS groups. Study-2 consisted of control, FUS only, gemcitabine, Doxil with FUS, and IMP301 (4 mg/kg) with or without FUS groups. Differences in tumor volume and growth rate were evaluated by one-way ANOVA and Student-Newman-Keuls test. RESULTS: In Study-1, 4 mg/kg or greater IMP301 with FUS groups showed lower tumor growth rates of 14 ± 4 mm3/day (mean ± standard deviation) or less, compared to the control, gemcitabine, and Doxil with FUS groups with rates exceeding 28 ± 5 (p < 0.050). The addition of FUS in Study-2 decreased the tumor growth rate in the IMP301-treated groups from 36 ± 17 to 9 ± 6, which was lower than the control, FUS only, gemcitabine, and Doxil with FUS groups (p < 0.050). CONCLUSIONS: IMP301 combined with FUS exhibited higher tumor growth suppression compared to the use of a conventional drug alone or the combination with FUS. The present study showed the potential of IMP301 to enhance the synergistic effect with FUS for the treatment of pancreatic cancer. RELEVANCE STATEMENT: This article aims to evaluate the synergistic effect of FUS and ultrasound-responsive liposomal drug in tumor growth suppression by using xenograft mouse model of pancreatic ductal adenocarcinoma. FUS-induced ultrasound-sensitive drug release may be a potential noninvasive repeatable treatment option for patients with locally advanced or unresectable pancreatic cancer. KEY POINTS: • Modification of conventional drugs combined with FUS would maximize tumor suppression. • IMP301 with FUS had higher tumor suppression effect compared to conventional chemotherapy. • This image-guided drug delivery would enhance therapeutic effects of systemic chemotherapy.

AC electrical breakdown phenomena of epoxy/layered silicate nanocomposite in needle-plate electrodes.

Epoxy/layered silicate nanocomposite for the insulation of heavy electric equipments were prepared by dispersing 1 wt% of a layered silicate into an epoxy matrix with a homogenizing mixer and then AC electrical treeing and breakdown tests were carried out. Wide-angle X-ray diffraction (WAXD) analysis and transmission electron microscopy (TEM) observation showed that nano-sized monolayers were exfoliated from a multilayered silicate in the epoxy matrix. When the nano-sized silicate layers were incorporated into the epoxy matrix, the breakdown rate in needle-plate electrode geometry was 10.6 times lowered than that of the neat epoxy resin under the applied electrical field of 520.9 kV/mm at 30 degrees C, and electrical tree propagated with much more branches in the epoxy/layered silicate nanocomposite. These results showed that well-dispersed nano-sized silicate layers retarded the electrical tree growth rate. The effects of applied voltage and ambient temperature on the tree initiation, growth, and breakdown rate were also studied, and it was found that the breakdown rate was largely increased, as the applied voltage and ambient temperature increased.

A new deposition method for the preparation of Pt-Pd nanocatalysts on a nafion coated carbon black via the reduction of metallic precursors in a drying process.

A simple method for the synthesis of Pt-Pd nanocatalysts was developed for a proton-exchange membrane fuel cell (PEMFC), which was loaded on a nafion coated carbon black via the sequential reduction of palladium(II) bis(acetylacetonato) and platinum(II) bis(acetylacetonato) in a drying process. Metallic precursors were sublimed and reduced on a nafion coated carbon black which was spray coated on a gas diffusion layer (GDL) in a glass reactor of N2 atmosphere at 180 degrees C for various times. The morphology and distribution of the Pt and Pd nanoparticles were observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and we found that the loading weight, number density and particle size of Pt-Pd nanoparticles increased with increasing exposure time at 180 degrees C.

Implantable polypyrrole bioelectrodes inducing anti-inflammatory macrophage polarization for long-term in vivo signal recording.

Bioelectrodes are critical components of implantable electronic devices that enable precise electrical signal transmission in close contact with living tissues. However, their in vivo performance is often compromised by inflammatory tissue reactions mainly induced by macrophages. Hence, we aimed to develop implantable bioelectrodes with high performance and high biocompatibility by actively modulating the inflammatory response of macrophages. Consequently, we fabricated heparin-doped polypyrrole electrodes (PPy/Hep) and immobilized anti-inflammatory cytokines (interleukin-4 [IL-4]) via non-covalent interactions. IL-4 immobilization did not alter the electrochemical performance of the original PPy/Hep electrodes. In vitro primary macrophage culture revealed that IL-4-immobilized PPy/Hep electrodes induced anti-inflammatory polarization of macrophages, similar to the soluble IL-4 control. In vivo subcutaneous implantation indicated that IL-4 immobilization on PPy/Hep promoted the anti-inflammatory polarization of host macrophages and significantly mitigated scarring around the implanted electrodes. In addition, high-sensitivity electrocardiogram signals were recorded from the implanted IL-4-immobilized PPy/Hep electrodes and compared to bare gold and PPy/Hep electrodes, which were maintained for up to 15 days post-implantation. This simple and effective surface modification strategy for developing immune-compatible bioelectrodes will facilitate the development of various electronic medical devices that require high sensitivities and long-term stabilities. STATEMENT OF SIGNIFICANCE: To fabricate highly immunocompatible conductive polymer-based implantable electrodes with high performance and stability in vivo, we introduced the anti-inflammatory activity to PPy/Hep electrodes by immobilizing IL-4 via non-covalent surface modification. IL-4-immobilized PPy/Hep could significantly mitigate inflammatory responses and scarring around implants by skewing macrophages to an anti-inflammatory phenotype. The IL-4-immobilized PPy/Hep electrodes could successfully record in vivo electrocardiogram signals for up to 15 days with no substantial sensitivity loss, retaining their superior sensitivity compared to bare gold and pristine PPy/Hep electrodes. Our simple and effective surface modification strategy for developing immune-compatible bioelectrodes will facilitate the development of various electronic medical devices that require high sensitivities and long-term stabilities, such as neural electrode arrays, biosensors, and cochlear electrodes.

Oral Probiotics, Streptococcus salivarius K12 and M18, Suppress the Release of Volatile Sulfur Compounds and a Virulent Protease from Oral Bacteria: An In-Vitro Study.

PURPOSE: To evaluate the inhibitory effects of Streptococcus salivarius K12 and M18 strains on the growth of six oral pathogens as well as their release of volatile sulfur compounds (VSCs), and whether these probiotics can inhibit the expression of arginine-specific gingipain A (RgpA), a protease secreted by Porphyromonas gingivalis. MATERIALS AND METHODS: After six halitogenic oral pathogens (P. gingivalis, Treponema denticola, Tannerella forsythia, Fusobacterium nucleatum, Parvimonas micra, and Eikenella corrodens) were cultured with or without S. salivarius K12 and M18, the concentration of two VSCs was measured. Moreover, the antimicrobial activity of S. salivarius K12 and M18 against these pathogens and the suppressive effect on RgpA release by P. gingivalis were assessed. RESULTS: In the co-culture of S. salivarius K12 or M18 with oral pathogenic bacteria, the growth of all six oral pathogens was significantly inhibited (p < 0.01). Additionally, S. salivarius K12 and M18 had an inhibitory effect on the production of the halitogenic substances H2S and CH3SH (p < 0.01) as well as the expression of P. gingivalis RgpA. Finally, we demonstrated that the addition of only culture supernatants of the two strains K12/M18 to oral pathogen cultures was sufficient to mimic the effects of K12/M18 co-cultures upon VSCs production and protease expression. CONCLUSIONS: S. salivarius K12 and M18 inhibited VSC release by all six of the major oral pathogens that were assayed and reduced the expression of RgpA.

Sialic acid-decorated liposomes enhance the anti-cancer efficacy of docetaxel in tumor-associated macrophages.

Tumor-associated macrophages (TAMs) in the tumor microenvironment potentially enhance tumor growth and invasion through various mechanisms and are thus an essential factor in tumor immunity. The highly expressed siglec-1 receptors on the surfaces of TAMs are potential targets for cancer drug delivery systems. Sialic acid (SA) is a specific ligand for siglec-1. In this study, the sialic acid-polyethylene glycol conjugate (DSPE-PEG2000-SA) was synthesized to modify the surface of liposomes and target TAMs by interacting with the siglec-1 receptor. Three docetaxel (DTX)-loaded liposomes, conventional (DTX-CL), DSPE-PEG2000-coated (DTX-PL), and DSPE-PEG2000-SA-coated (DTX-SAPL) liposomes, were prepared, with a particle size of <100 nm, uniform polydispersity index (PDI) values, negative zeta potential, and % encapsulation efficiency (EE) exceeding 95 %. Liposomes showed high stability after 3 months of storage at 4 °C without significant changes in particle size, PDI, zeta potential, or % EE. DTX was released from liposomes according to the Weibull model, and DTX-SAPL exhibited more rapid drug release than other liposomes. In vitro studies demonstrated that DTX-SAPL liposome exhibited a higher uptake and cytotoxicity on RAW 264.7 cells (TAM model) and lower toxicity on NIH3T3 cells (normal cell model) than other formulations. The high cell uptake ability was demonstrated by the role of the SA-SA receptor. Biodistribution studies indicated a high tumor accumulation of surface-modified liposomal formulations, particularly SA-modified liposomes, showing high signal accumulation at the tumor periphery, where TAMs were highly concentrated. Ex vivo imaging showed a significantly higher accumulation of SA-modified liposomes in the tumor, kidney, and heart than conventional liposomes. In the anti-cancer efficacy study, DTX-SAPL liposomes showed effective inhibition of tumor growth and relatively low systemic toxicity, as evidenced by the tumor volume, tumor weight, body weight values, and histopathological analysis. Therefore, DSPE-PEG2000-SA-coated liposomes could be promising carriers for DTX delivery targeting TAMs in cancer therapy.