Nanosized Porphyrin-Containing Covalent Organic Polymer to Enhance Ferroptosis in Photodynamic Treatment of Tumor Cells via Glutathione Depletion.

A porphyrin-containing nanoscale covalent organic polymer (COP) was fabricated from 5,10,15,20-tetra(4-carboxyphenyl)porphyrin (TCPP) and cystamine via an acylation reaction. On the one hand, TCPP can induce tumor cell death by laser irradiation. Due to the presence of disulfide bonds of cystamine which can react with glutathione, it exhibits depletion of glutathione and accumulation of peroxides in tumor cells. Ultimately by the hyaluronic acid to encapsulate the COP to get S-COP@HA, the nanoparticle with a size of 168.6 nm also exhibits good tumor accumulation and biosafety. Significant inhibition of tumor cell growth was observed after two consecutive doses of S-COP@HA at relatively low laser densities. This combination therapy was proved to reduce the level of reduced glutathione in tumor cells, where ferroptosis occurs after photodynamic treatment. Overall, this study presents a potent, good therapeutic option for the effective enhancement of photodynamic therapy by glutathione depletion.

Transmission routes of SARS-CoV-2 and protective measures in dental clinics during the COVID-19 pandemic.

RESULTS: The outbreak of coronavirus disease 2019 (COVID-19) has become a primary challenging public health issue for not only China but also the world. On March 11, 2020, the World Health Organization declared that the pandemic of COVID-19 had become a public health emergency of global concern. As of May 12, 2020 COVID-19 has been reported in over 180 countries/regions, with a total of 4,178,156 confirmed cases and over 280,000 deaths. The risk of cross-infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) might be elevated between dental specialists and patients due to the peculiarity of dental practice. Therefore, detailed and effective infection control measures are imminently needed to prevent nosocomial coronavirus infection. This paper, based on proven effective experience, relevant guidelines, and research, not only presents the fundamental knowledge about the name, etiologic characteristics, epidemiologic characteristics and clinical manifestations of COVID-19, transmission routes and risk points of SARS-CoV-2 in dental clinics but also provides recommended protective measures for dental professionals to interdict the transmission of SARS-CoV-2 in dental clinics. Classification schemes as well as color identification according to the results of the questionnaire survey and temperature measurement in precheck and triages are innovations proposed in this paper. CLINICAL SIGNIFICANCE: This paper, based on proven effective experience, relevant guidelines, and research, not only presents the fundamental knowledge about the name, etiologic characteristics, epidemiologic characteristics and clinical manifestations of COVID-19, transmission routes and risk points of SARS-CoV-2 in dental clinics but also provides recommended protective measures for dental professionals to interdict the transmission of SARS-CoV-2 in dental clinics.

The effect of platform switching on stress distribution in implants and periimplant bone studied by nonlinear finite element analysis.

STATEMENT OF PROBLEM: It is unknown whether dental implant systems with a platform-switched configuration have better periimplant bone stress distribution and lead to less periimplant bone level changes. PURPOSE: The purpose of this study was to quantitatively investigate interfacial stress and stress distribution in implant bone in 2 implant abutment designs (platform-switched design and conventional diameter matching) by using a nonlinear finite element analysis method. MATERIAL AND METHODS: A finite element simulation study was applied to 2 commercially available dental implant systems: the Ankylos implant system with a reduced-diameter abutment (platform-switched implant) and the Anthogyr implant system with an abutment of the same diameter (regular platform implant). These 2 dental implant systems were positioned in a bone block, which was constructed based on a cross-sectional image of a human mandible in the molar region. In simulation, a single vertical load of 50 N, 100 N, or 150 N and horizontal loads of 50 N and 100 N were applied to the occlusal surface of the abutment. RESULTS: The finite element analysis found that the Ankylos implant system has a higher maximum von Mises stress in the implant abutment connection section and a lower maximum von Mises stress in the periimplant bone. The opposite results were found in the Anthogyr implant system. CONCLUSIONS: Lower stress levels in the periimplant bone with a more uniform stress distribution were found for the Ankylos implant system with a platform-switched configuration. Although relatively higher stress was found in the abutment, premature implant failure is not anticipated because of the high strength of titanium alloy.

Nanoemulsion-integrated gelatin/bacterial cellulose nanofibril-based multifunctional film: Fabrication, characterization, and application.

The current requirements of food safety regulations and the environmental impact stemming from plastic packaging can only be addressed by developing suitable bio-nanocomposite films. Therefore, this study is dedicated to the fabrication of multifunctional film composed of gelatin, bacterial cellulose nanofibrils (BCNF), and black pepper essential oil nanoemulsion (BPEONE) and application for duck meat preservation. BCNF was prepared through ultrasonication of cellulose derived from Komagataeibacter xylinus. BPEONE observed spherical morphology with a diameter ranging from 83.7 to 118 nm. A film matrix containing a higher gelatin proportion than BCNF was more effective in trapping BPEONE. However, increasing the BPEONE fraction showed more surface abrasion and voids in the film morphology. A flexible film with good interaction, crystallinity, and greater thermal stability (421 °C) was developed. Nevertheless, film hydrophobicity (118.89°) declined, resulting in a notable effect on water solubility, swelling, and water vapor permeability. Moreover, the film had improved antibacterial and antioxidant activities, coupled with controlled release characteristics. Consequently, the developed film effectively retarded the lipid oxidation, inhibited microbial growth, and extended the shelf life of duck meat at refrigeration (4 °C) by 3 days, and made the film a promising alternative in the realm of bio-active packaging technology.

Thermal aging of polystyrene microplastics within mussels (Mytilus coruscus) under boiling and drying processing.

Aged microplastics (MPs) in the environment are a growing concern due to their higher ecological toxicity compared to pristine MPs. While previous studies have explored aging behaviors of MPs under various stress conditions, little is known about their aging during food processing. In this study, we investigated the effects of different thermal food processing methods on the aging of polystyrene (PS) MPs within mussels. We subjected the mussels containing PS MPs to boiling, boiling/solar drying, boiling/hot air drying, and boiling/microwave drying treatments, all of which are common preservation methods used in industry. We analyzed the particle size, surface morphology, yellowing, crystallinity, chemical groups, and hydrophilicity of the PS MPs to understand the aging process. Results show that all processing methods led to aging of PS MPs, with boiling/microwave drying having the most significant impact, followed by boiling/hot air drying, boiling/solar drying, and boiling alone. The aged PS MPs exhibited smaller size, morphological changes, reduced crystallinity, increased yellowness index and carbonyl index, higher presence of O-containing groups, and enhanced hydrophilicity. These findings provide evidence of MPs aging during thermal food processing and emphasize the potential risks associated with this pathway.

Foam Cell Targeted Liposomes Co-Encapsulating Superoxide Dismutase and Catalase to Attenuate Atherosclerosis by Inhibiting Oxidative Stress.

BACKGROUND: Oxidative stress, propelled by reactive oxygen species (ROS), serves as a significant catalyst for atherosclerosis (AS), a primary contributor to vascular diseases on a global scale. Antioxidant therapy via nanomedicine has emerged as a pivotal approach in AS treatment. Nonetheless, challenges such as inadequate targeting, subpar biocompatibility, and limited antioxidant effectiveness have restrained the widespread utilization of nanomedicines in AS treatment. This study aimed to synthesize a specialized peptide-modified liposome capable of encapsulating two antioxidant enzymes, intending to enhance targeted antioxidant therapy for AS. METHODS: The film dispersion method was employed for liposome preparation. Fluorescence quantification was conducted to assess the drug encapsulation rate. Characterization of liposome particle size was performed using dynamic light scattering (DLS) and transmission electron microscopy (TEM). Laser confocal microscopy and flow cytometry were utilized to analyze liposome cell uptake and target foam cells. Antioxidant analysis was conducted using 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) staining, while pro-lipid efflux analysis utilized Oil Red O (ORO) staining. Safety evaluation was performed using Hematoxylin and Eosin (H&E) staining. The level of inflammatory factors was determined through enzyme-linked immunosorbent assay (ELISA). The degree of lipid oxidation at the cellular level was assessed using the malonaldehyde (MDA) assay. In vivo targeting analysis was conducted using small animal live imaging. RESULTS: Our in vitro and in vivo findings substantiated that the modification of Lyp-1 led to increased delivery of antioxidant enzymes into foam cells (p < 0.05), the primary pathological cells within AS plaques. Upon accumulation in foam cells, liposomes loaded with superoxide dismutase (SOD) and catalase (CAT) (LyP-lip@SOD/CAT) effectively mitigated excess ROS and shielded macrophages from ROS-induced damage (p < 0.01). Furthermore, the reduction in ROS levels notably hindered the endocytosis of oxidized low-density lipoprotein (Ox-LDL) by activated macrophages, subsequently alleviating lipid accumulation at atherosclerotic lesion sites, evident from both in vitro and in vivo ORO staining results (p < 0.01). LyP-lip@SOD/CAT significantly curbed the secretion of inflammatory factors at the plaque site (p < 0.001). Additionally, LyP-lip@SOD/CAT demonstrated commendable biological safety. CONCLUSIONS: In this study, we effectively synthesized LyP-lip@SOD/CAT and established its efficacy as a straightforward and promising nano-agent for antioxidant therapy targeting atherosclerosis.

Impacts of microplastic-petroleum pollution on nutrient uptake, growth, and antioxidative activity of Chlorella vulgaris.

As one of the emerging pollutants, microplastics (MPs; <5 mm) can interact with co-contaminants such as petroleum in marine aquatic systems, and their combined toxicity has not been fully investigated. Therefore, this study focused on pollutants such as micro-sized polyethylene (mPE) and petroleum, aiming to explore their single and combined toxicities to microalga Chlorella vulgaris in terms of the cell growth, antioxidative enzymes, and nutrients utilization. The results showed that the MPs alone (particle sizes (i.e., 13, 165, 550 µm), concentrations (i.e., 0.01, 0.1, and 1 g/L), and aging degrees (i.e., aged for 0 d and 90 d under UVA)), and petroleum alone (5% water accommodated fraction, WAF), and their combinations (i.e., 5% WAF + 165 µm-0.1 g/L-aged 0 d mPE, 5% WAF + 165 µm-0.1 g/L-aged 90 d mPE) all posed toxicities risk to C. vulgaris, following an increase in oxidative stress. The cellular utilization of elements such as Fe, Si, Ca, and Mg was inhibited, whereas the uptake of Mn, NO3--N, and PO43--P increased as compared to the control experiments. Furthermore, the relationship between nutrients and growth indicators was analyzed using a structural equation model. The results indicated that Fe and Mn directly affected the indirect NO3--N absorption by C. vulgaris, which indirectly affected the dry cell weight (DCW) of the microalgae. The path coefficient of Fe and Mn affecting nitrate was 0.399 and 0.388, respectively. The absorption of N was the key step for C. vulgaris resist stress. This study provides a novel analysis of the effects of MPs on the growth of microalgae from the perspective of nutrient elements, thereby providing a useful basis for further exploration of the associated mechanisms.

A dual-emission polymer carbon nanoparticles for ratiometric and visual detection of pH value and bilirubin.

Herein, we prepared a novel fluorescent polymer carbon nanoparticles by polymerizing dopamine (DA) and o-phenylenediamine (OPD) through oxidation of hydrogen peroxide. In a neutral environment, the synthesized fluorescent polymer carbon nanoparticles (PDA-OPD) exhibited two emission peaks at 460 nm and 540 nm with 400 nm excitation wavelength. In an acidic environment, the fluorescence emission peaks of PDA-OPD at 540 nm showed an obvious fluorescence quenching, and there existed a good linear relationship between the fluorescence ratio F540/F460 and environment pH value. In an alkaline environment, the fluorescence emission peak at 460 nm showed obvious fluorescence quenching after the addition of bilirubin, while a novel fluorescence emission peak at 560 nm emerged gradually. The PDA-OPD could be also used to detect bilirubin in the range of 0-400 µmol·L-1.

3D printed chitosan-gelatine hydrogel coating on titanium alloy surface as biological fixation interface of artificial joint prosthesis.

To improve the fixation of the prosthesis-bone interface and to prevent postoperative infection, a novel antimicrobial hydrogel coating is designed as the biological fixation interface of the artificial joint prosthesis. Antimicrobial chitosan (CS) and gelatine (GT) were used as bioinks to print a CS-GT hydrogel coating with reticulated porous structure on the titanium alloy substrate by 3D printing technology. The experimental results show that the 7CS-10GT hydrogel coating has a macro-grid structure and honeycomb micro-network structure, excellent hydrophilicity (35.64°), high mechanical strength (elastic modulus 0.92 MPa) and high bonding strength (3.36 MPa) with the titanium alloy substrate. In addition, the antimicrobial effect of 7CS-10GT hydrogel against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) is enhanced after immersion in nano­silver. Moreover, the 7CS-10GT hydrogel displays good cell compatibility and supports proliferation of NIH-3 T3 cells. In summary, the 3D printed CS-GT antimicrobial hydrogel coating provides an ideal microenvironment for cell adhesion and bone growth due to the dual-scale porous network structure, good hydrophilicity and biocompatibility, thus promoting rapid fixation of the bone interface. This technology opens a new possibility for this biological fixation interface in artificial joint replacement.

In situ reduction of silver nanoparticles by sodium alginate to obtain silver-loaded composite wound dressing with enhanced mechanical and antimicrobial property.

Wound dressings provide barrier protection during wound treatment while providing an environment suitable for wound healing. However, traditional wound dressings have disadvantages, such as easily adhering to wounds, poor barrier effects, and poor haemostasis. Therefore, it is of great significance to design a new wound dressing that does not cause further injury, has good antibacterial effect and promotes wound healing in view of the disadvantages of traditional wound dressings. In this paper, silver nanoparticles (AgNPs) were reduced by in situ reduction with sodium alginate (SA), and construct a silver-loaded PVA/SA/CMCS hydrogel antibacterial wound dressing. The properties of antibacterial hydrogel were evaluated. The results show that SA can successfully reduce AgNPs, and the particle size is small and uniform, which meets the requirements of antibacterial material. The AgNPs are evenly distributed inside the hydrogel and have stable performance. The silver-loaded hydrogel was formed uniform pores inside the material, and had excellent water absorption and water retention, which can absorb a large amount of wound exudate while maintaining a moist wound environment. The antibacterial hydrogel exhibited good mechanical properties, antibacterial activity and biocompatibility. In summary, the silver-loaded hydrogel is an ideal wound dressing.

Study on preparation, characterization and multidrug resistance reversal of red blood cell membrane-camouflaged tetrandrine-loaded PLGA nanoparticles.

The multidrug resistance in tumor (MDR) is a major barrier to efficient cancer therapy. Modern pharmacological studies have proven that tetrandrine (TET) has great potential in reversing MDR. However, it has a series of medication problems in clinic such as poor water solubility, low oral bioavailability and short half-life in vivo. Aiming at the above problems, red blood cell membrane-camouflaged TET-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles (RPTNs) had been developed. The RPTNs had spherical shell-core double layer structure with average particle size of 164.1 ± 1.65 nm and encapsulation efficiency of 84.1% ± 0.41%. Compared with TET-PLGA nanoparticles (PTNs), the RPTNs reduced RAW 264.7 macrophages' swallowing by 32% due to its retention of natural membrane proteins. The cumulative drug release of RPTNs was 81.88% within 120 h. And pharmacokinetic study showed that the blood half-life of RPTNs was 19.38 h, which was 2.95 times of free drug. When RPTNs of 2 µg/mL TET were administered in combination with adriamycin (ADR), significant MDR reversal effect was observed in drug-resistant cells MCF-7/ADR. In a word, the RPTNs hold potential to improve its efficacy and broaden its clinical application.

Dual-channel-coded microbeads for multiplexed detection of biomolecules using assembling of quantum dots and element coding nanoparticles.

To achieve the dual-channel (analog and digital) encoding, microbeads assembled with quantum dots (QDs) and element coding nanoparticles (ECNPs) have been prepared. Dual-spectra, including fluorescence generated from quantum dots (QDs) and laser induced breakdown spectrum obtained from the plasma of ECNPs, including AgO, MgO and ZnO nanoparticles, has been adopted to provide more encoding amounts and more accurate dual recognition for encoded microbeads in multiplexed utilization. The experimental results demonstrate that the single microbead can be decoded in two optical channels. Multiplexed analysis and contrast adsorption experiment of anti-IgG verified the availability and specificity of dual-channel-coded microbeads in bioanalysis. In gradient detection of anti-IgG, we obtained the linear concentration response to target biomolecules from 3.125 × 10-10 M to 1 × 10-8 M, and the limit of detection was calculated to be 2.91 × 10-11 M.

Spindle cell carcinoma of the mandible: a case report.

Spindle cell carcinoma is a rare highly malignant squamous cell carcinoma. Here, we describe a case of a 74-year-old Chinese female who presented with a 2-week history of pain and swelling in the left retromolar region. Surgical resection and titanium plate prosthesis were performed and histological analysis revealed spindle squamous cell carcinoma.