Enhancing near-infrared II photodynamic therapy with nitric oxide for eradicating multidrug-resistant biofilms in deep tissues

Nitric oxide (NO) enhanced photodynamic therapy (PDT) is a promising approach to overcome drug tolerance and resistance to biofilm but is limited by its short excitation wavelengths and low yield of reactive oxygen species (ROS). Herein, we develop a compelling degradable polymer-based near-infrared II (NIR-II, 1000-1700 nm) photosensitizer (PNIR-II), which can maintain 50 % PDT efficacy even under a 2.6 cm tissue barrier. Remarkably, PNIR-II is synthesized by alternately connecting the electron donor thiophene to the electron acceptors diketopyrrolopyrrole (DPP) and boron dipyrromethene (BODIPY), where the intramolecular charge transfer properties can be tuned to increase the intersystem crossover rate and decrease the internal conversion rate, thereby stabilizing the NIR-II photodynamic rather than photothermal effect. For exerting a combination therapy to eradicate multidrug-resistant biofilms, PNIR-II is further assembled into nanoparticles (NPs) with a synthetic glutathione-triggered NO donor polymer. Under 1064 nm laser radiation, NPs precisely release ROS and NO that triggered by over-expressed GSH in the biofilm microenvironment, thereby forming more bactericidal reactive nitrogen species (RNS) in vitro and in vivo in the mice model that orderly destroy biofilm of multidrug-resistant Staphylococcus aureus cultures from clinical patients. It thus provides a new outlook for destroy the biofilm of deep tissues.

GSH/pH Cascade-Responsive Nanoparticles Eliminate Methicillin-Resistant Staphylococcus aureus Biofilm via Synergistic Photo-Chemo Therapy

Bacterial biofilm infection threatens public health, and efficient treatment strategies are urgently required. Phototherapy is a potential candidate, but it is limited because of the off-targeting property, vulnerable activity, and normal tissue damage. Herein, cascade-responsive nanoparticles (NPs) with a synergistic effect of phototherapy and chemotherapy are proposed for targeted elimination of biofilms. The NPs are fabricated by encapsulating IR780 in a polycarbonate-based polymer that contains disulfide bonds in the main chain and a Schiff-base bond connecting vancomycin (Van) pendants in the side chain (denoted as SP-Van@IR780 NPs). SP-Van@IR780 NPs specifically target bacterial biofilms in vitro and in vivo by the mediation of Van pendants. Subsequently, SP-Van@IR780 NPs are decomposed into small size and achieve deep biofilm penetration due to the cleavage of disulfide bonds in the presence of GSH. Thereafter, Van is then detached from the NPs because the Schiff base bonds are broken at low pH when SP@IR780 NPs penetrate into the interior of biofilm. The released Van and IR780 exhibit a robust synergistic effect of chemotherapy and phototherapy, strongly eliminate the biofilm both in vitro and in vivo. Therefore, these biocompatible SP-Van@IR780 NPs provide a new outlook for the therapy of bacterial biofilm infection.

Dual Coordination between Stereochemistry and Cations Endows Polyethylene Terephthalate Fabrics with Diversiform Antimicrobial Abilities for Attack and Defense

Modification of fabrics by stereochemical antiadhesion strategies is an emerging approach to antimicrobial fabric finishing. However, a purely antiadhesive fabric cannot avoid the passive adhesion of pathogenic microorganisms. To address this issue, borneol 4-formylbenzoate (BF) with a stereochemical structure is introduced into a cationic polymer PEI-modified PET fabric by a simple two-step method. The obtained fabric exhibits remarkable features of high bactericidal activity, excellent resistance to bacterial adhesion, desirable fungal repellent performance, and low cytotoxicity. More impressively, this modified fabric not only effectively reduces microbial contamination during food preservation but also plays a role in avoiding infection and accelerating wound healing in the mouse wound model. The dual coordination between stereochemistry and cations is validated as a viable "attack and defense" antimicrobial strategy, providing an effective guide for diversiform antimicrobial designs.

An Acid-triggered Reactive and Enhanced Fluorescent Probe for Selective Detection of Al3+/H+ and its Application in Real Water Samples and Living Cells

A reactive fluorescent "turn-on" probe (di-PIP) with imine-linked dual phenanthro[9,10-d]imidazole luminophore have been conveniently prepared as an Al³⁺ and H⁺ dual functional receptor. di-PIP displayed high selectivity and sensitivity towards Al³⁺ ion in DMF/HEPES accompanied by fluorescence blue-shift and a good linear relationship as well as a low detection limit of 30.5 nmol·L^-1, which can root from the synergetic functions of the decomposition reaction of di-PIP promoted by acidic Al³⁺ and the coordination effect between decomposition product and Al³⁺. Intriguingly, it was found that hydrogen ion H⁺ can be sufficient for simulating the fluorescence enhancing of di-PIP. ¹H NMR titration and MS analyses for elucidation of the intermediate structure further revealed that the acid-triggered decomposition reaction resulted in the rapid, and sensitive sensing to Al³⁺ and H⁺. In addition, the probe di-PIP could be successfully applied to the detection of Al³⁺ in real water samples, and also utilized to visualize Al³⁺ and H⁺ in the living cells.

Dual-Cascade Responsive Nanoparticles Enhance Pancreatic Cancer Therapy by Eliminating Tumor-Resident Intracellular Bacteria

The limited drug penetration and robust bacteria-mediated drug inactivation in pancreatic cancer result in the failure of chemotherapy. To fight against these issues, a dual-cascade responsive nanoparticle (sNP@G/IR) that can sequentially trigger deep penetration, killing of intratumor bacteria, and controlled release of chemo-drug, is reported. sNP@G/IR consists of a hyaluronic acid (HA) shell and glutathione (GSH)-responsive polymer-core (NP@G/IR), that encapsulates gemcitabine (Gem) and photothermal agent (IR1048). The polymer core, as an antibiotic alternative, is tailored to exert optimal antibacterial activity and selectivity. sNP@G/IR actively homes in on the tumor due to the CD44 targeting of the HA shell, which is subsequently degraded by the hyaluronidase in the extracellular matrix. The resultant NP@G/IR in decreased size and reversed charge facilitates deep tumor penetration. After cellular endocytosis, the exposed guanidine on NP@G/IR kills intracellular bacteria through disrupting cell membranes. Intracellular GSH further triggers the controlled release of the cargo. Thus, the protected Gem eventually induces cell apoptosis. Under laser irradiation, the hyperthermia of IR1048 helps further elimination of tumors and bacteria. Moreover, sNP@G/IR activates immune response, thereby reinforcing anticancer capacity. Therefore, this dual-cascade responsive sNP@G/IR eliminates tumor-resident intracellular bacteria and augments drug delivery efficacy, providing a new avenue for improving cancer therapy.

Longitudinal changes in home-based arts engagement during and following the first national lockdown due to the COVID-19 pandemic in the UK

Aims:

This study aimed to examine potential heterogeneity in longitudinal changes in home-based arts engagement during the first national lockdown and following gradual easing of restrictions in the UK. Furthermore, it sought to explore factors that were associated with patterns of longitudinal changes in home-based arts engagement.

Method:

Data were from the UCL COVID-19 Social Study. The analytical sample consisted of 29,147 adults in the UK who were followed up for 22 weeks from 21 March to 21 August 2020. Data were analysed using growth mixture models.

Results:

Our analyses identified five classes of growth trajectories. There were two stable classes showing little change in arts engagement over time (64.4% in total), two classes showing initial increases in arts engagement followed by declines as restrictions were eased (29.8%), and one class showing slight declines during strict lockdown followed by an increase in arts engagement after the easing of restrictions (5.9%). A range of factors were found to be associated with class membership of these arts engagement trajectories, such as age, gender, education, income, employment status, and health.

Conclusion:

There is substantial heterogeneity in longitudinal changes in home-based arts engagement. For participants whose engagement changed over time, growth trajectories of arts engagement were related to changes in lockdown measures. These findings suggest that some individuals may have drawn on the arts when they needed them the most, such as during the strict lockdown period, even if they usually had lower levels of arts engagement before the pandemic. Overall, our results indicate the importance of promoting arts engagement during pandemics and periods of lockdown as part of public health campaigns.

Cascade-Targeting Poly(amino acid) Nanoparticles Eliminate Intracellular Bacteria via On-Site Antibiotic Delivery

Intracellular bacteria in latent or dormant states tolerate high-dose antibiotics. Fighting against these opportunistic bacteria has been a long-standing challenge. Herein, the design of a cascade-targeting drug delivery system (DDS) that can sequentially target macrophages and intracellular bacteria, exhibiting on-site drug delivery, is reported. The DDS is fabricated by encapsulating rifampicin (Rif) into mannose-decorated poly(α-N-acryloyl-phenylalanine)-block-poly(β-N-acryloyl-d-aminoalanine) nanoparticles, denoted as Rif@FAM NPs. The mannose units on Rif@FAM NPs guide the initial macrophage-specific uptake and intracellular accumulation. After the uptake, the detachment of mannose in acidic phagolysosome via Schiff base cleavage exposes the d-aminoalanine moieties, which subsequently steer the NPs to escape from lysosomes and target intracellular bacteria through peptidoglycan-specific binding, as evidenced by the in situ/ex situ co-localization using confocal, flow cytometry, and transmission electron microscopy. Through the on-site Rif delivery, Rif@FAM NPs show superior in vitro and in vivo elimination efficiency than the control groups of free Rif or the DDSs lacking the macrophages- or bacteria-targeting moieties. Furthermore, Rif@FAM NPs remodel the innate immune response of the infected macrophages by upregulating M1/M2 polarization, resulting in a reinforced antibacterial capacity. Therefore, this biocompatible DDS enabling macrophages and bacteria targeting in a cascade manner provides a new outlook for the therapy of intracellular pathogen infection.

Inserting Menthoxytriazine into Poly(ethylene terephthalate) for Inhibiting Microbial Adhesion

Antimicrobial modification of poly(ethylene terephthalate) (PET) is effective in preventing the adhesion and growth of microorganisms on its surface. However, few methods are available to modify PET directly at its backbone to impart the antimicrobial effect. Herein, menthoxytriazine-modified PET (PMETM) based on the stereochemical antimicrobial strategy was reported. This novel PET was prepared by inserting menthoxytriazine into the PET backbone. The antibacterial adhesion test and the antifungal landing test were employed to confirm the antiadhesion ability of PMETM. PMETM could effectively inhibit the adhesion of bacteria, with inhibition ratios of 99.9 and 99.7% against Escherichia coli (Gram-negative) and Bacillus subtilis (Gram-positive), respectively. In addition, PMETM exhibited excellent resistance to Aspergillus niger (fungal) contamination for more than 30 days. Cytotoxicity assays indicated that PMETM was a noncytotoxic material. These results suggested that the insertion of menthoxytriazine in the PET backbone was a promising strategy to confer antimicrobial properties to PET.

Who is lonely in lockdown? Cross-cohort analyses of predictors of loneliness before and during the COVID-19 pandemic

BACKGROUND

There are concerns internationally that lockdown measures taken during the coronavirus disease 2019 (COVID-19) pandemic could lead to a rise in loneliness. As loneliness is recognised as a major public health concern, it is therefore vital that research considers the impact of the current COVID-19 pandemic on loneliness to provide necessary support. But it remains unclear, who is lonely in lockdown?

METHODS

This study compared sociodemographic predictors of loneliness before and during the COVID-19 pandemic using cross-cohort analyses of data from UK adults captured before the pandemic (UK Household Longitudinal Study, n = 31,064) and during the pandemic (UCL (University College London) COVID-19 Social Study, n = 60,341).

RESULTS

Risk factors for loneliness were near identical before and during the pandemic. Young adults, women, people with lower education or income, the economically inactive, people living alone and urban residents had a higher risk of being lonely. Some people who were already at risk of being lonely (e.g. young adults aged 18-30 years, people with low household income and adults living alone) experienced a heightened risk during the COVID-19 pandemic compared with people living before COVID-19 emerged. Furthermore, being a student emerged as a higher risk factor during lockdown than usual.

CONCLUSIONS

Findings suggest that interventions to reduce or prevent loneliness during COVID-19 should be targeted at those sociodemographic groups already identified as high risk in previous research. These groups are likely not just to experience loneliness during the pandemic but potentially to have an even higher risk than normal of experiencing loneliness relative to low-risk groups.

Who is lonely in lockdown? Cross-cohort analyses of predictors of loneliness before and during the COVID-19 pandemic

BACKGROUND

There are concerns internationally that lockdown measures taken during the coronavirus disease 2019 (COVID-19) pandemic could lead to a rise in loneliness. As loneliness is recognised as a major public health concern, it is therefore vital that research considers the impact of the current COVID-19 pandemic on loneliness to provide necessary support. But it remains unclear, who is lonely in lockdown?

METHODS

This study compared sociodemographic predictors of loneliness before and during the COVID-19 pandemic using cross-cohort analyses of data from UK adults captured before the pandemic (UK Household Longitudinal Study, n = 31,064) and during the pandemic (UCL (University College London) COVID-19 Social Study, n = 60,341).

RESULTS

Risk factors for loneliness were near identical before and during the pandemic. Young adults, women, people with lower education or income, the economically inactive, people living alone and urban residents had a higher risk of being lonely. Some people who were already at risk of being lonely (e.g. young adults aged 18-30 years, people with low household income and adults living alone) experienced a heightened risk during the COVID-19 pandemic compared with people living before COVID-19 emerged. Furthermore, being a student emerged as a higher risk factor during lockdown than usual.

CONCLUSIONS

Findings suggest that interventions to reduce or prevent loneliness during COVID-19 should be targeted at those sociodemographic groups already identified as high risk in previous research. These groups are likely not just to experience loneliness during the pandemic but potentially to have an even higher risk than normal of experiencing loneliness relative to low-risk groups.

A phenanthro[9,10-d]imidazole-based AIE active fluorescence probe for sequential detection of Ag+/AgNPs and SCN- in water and saliva samples and its application in living cells

Ag⁺ and SCN^- play extremely important roles in the fields of the physiology and environment. In this work, on the basis of phenanthro[9,10-d]imidazole derivative (DIPIP) which can exhibit the aggregation-induced emission (AIE) properties in aqueous solution, we achieved a sequential on-off-on switch for Ag⁺ and SCN^- with high selectivity and sensitivity. A remarkable fluorescence quenching effect of Ag⁺ on the probe DIPIP was observed with 1:2 stoichiometry, Subsequently, the fluorescence intensity of in situ generated DIPIP-Ag⁺ ensemble was easily switched on after the interaction between Ag⁺ and SCN^-, which was attributed to the stronger affinity of SCN^- to capture Ag⁺. In particular, the extreme limits of detection (LOD) for Ag⁺ and SCN^- in standard solutions were as low as to be 74.5 nM and 7.8 nM, respectively. Furthermore, the probe DIPIP and the DIPIP-Ag⁺ ensemble could be used to detect Ag⁺ in the real water and SCN^- in smoker saliva samples, respectively. In addition, the sequential "on-off-on" fluorescence mode of DIPIP to Ag⁺ and SCN^- were also successfully applied in living HeLa cells.

[Microdeletion and Mutation of Y Chromosome in Full Sibling Identification]

OBJECTIVES

To explore the identification method of full sibling between two males with microdeletion and mutation of Y chromosome.

METHODS

DNA were extracted from two samples. The type testing of Y-STR and autosomal STR were performed. Full sibling between two individuals was calculated by IBS, ITO and discriminant functions methods.

RESULTS

There were 2 loci mutations existed in 33 Y-STR loci and one of the two samples had 19 loci deletions. The IBS of two samples was 53 and greater than the threshold which was 42; FSI was 1.36×10¹⁶ and far greater than 19. The discriminant function of full sibling-unrelated individual D_FS2 was greater than D_R2, which meant the two individuals tend to be full sibling.

CONCLUSIONS

The methods of IBS, ITO and discriminant functions of full sibling-unrelated individual can be used comprehensively to provide more reliable expert opinion in microdeletion and mutation of Y chromosome in full sibling identification.

Pharmacokinetics of ginkgolide B injection in beagle dogs

A liquid chromatography-mass spectrometry method was developed, validated, and applied to the pharmacokinetic study with doses of 0.68, 2.73 and 10.92 mg/kg of ginkgolide B in beagle dogs after intravenous infusion.An aliquot of blood samples were -collected, separated and quantitatively analyzed by liquid chromatography-mass spectrometry method with mobile phase of acetonitrile-0.02% ammonia solution (33:67, v/v) at a flow rate of 0.8 mL/min on the UltimateTM XB-C18 column (5 μm, 4.6×150 mm).The method was sensitive, accurate and convenient, and can be used for the determination of ginkgolide B in beagle dogs. The Cmax and AUC0-∞ of GB increased with dose escalation, but ANOVA analyses showed that no significant difference was observed in other pharmacokinetic parameters between different doses.An LC/MS method was developed with good sensitivity, reproducibility and specificity. In the pharmacokinetic study of GB in beagle dogs, linear pharmacokinetics was found at doses from 0.62 to 10.92 mg/kg after a single-dose intravenous infusion. Gender differences were not observed in the pharmacokinetics of GB.

[The language healing system of deaf children based on wavelet transform]

In the language healing system of deaf children, the wavelet transform method is employed to describe the time-varying characteristics of speech signals, improve the resolution of speech spectrum and make the speech characteristics more obvious. The speech spectrum information shown in this system is easier for deaf children to observe and understand and it is of great importance to the language healing of deaf children.

[The quantitative analysis of voice disease based on fractal method]

The fractal method is employed to check the voice diseases. The severity of pathological changes of human voice can be analyzed objectively and quantitatively with different fractal dimensions. With this method we can end up the history of judging the voice with subjective hearing and it is of great importance to the development of laryngology.

[Analysis of impulse response of rectangular ultrasound transducer]

A new expression for calculating the impulse response of rectangular pistonlike transducers, proper to any points of acoustic field, is presented. The radiated field of ultrasound transducer can be analyzed using impulse response method, avoiding paraxial and farfield approximation. The velocity potential at an observation point is expressed as the convolution of the excitation velocity and the impulse response. A time-amplitude shift method for the far field impulse response of small aperture transducers is presented. The radiated field of rectangular transducers is calculated through the new method and the previous method and excellent agreement is observed.

Chromatography of human prothrombin from Nitschmann fraction III on DEAE Sepharose Fast Flow using axial and radial flow column

An axial column (3 x 2.6 cm) and a radial flow column (3.5 x 5 cm) packed with DEAE Sepharose Fast Flow media was evaluated for the separation of human prothrombin from Nitschmann fraction III. Under radial flow conditions, a sample flow rate up to 14 mL/min (approximately 18 bed vols/h) was achieved. Breakthrough capacity was determined and both columns had almost the same breakthrough capacity per mL media, indicating that the sample loading was independent of radial column geometry.

Studies on the resuscitative efficacy of polymerized bovine hemoglobin

The paper described modified hemoglobin (Hb) with glycolaldehyde for the efficacy on resuscitation of severe hemorrhagic shock. Our objective was to compare the effect on resuscitation of severe hemorrhagic shock with different experimental groups. Results showed early resuscitation with modified bovine Hb is superior to lactated Ringer's solution group in improving hemodynamic and acidosis, but the effect of polymerized Hb with glycolaldehyde were similar to fresh whole blood in this rat model.

Purification of human prothrombin from Nitschmann fraction III using DEAE membrane radial flow chromatography

A DEAE membrane radial column (4x5 cm) was used to purify human prothrombin from Nitschmann fraction III and performances of the column were investigated. Sample flow-rate of 20-30 ml/min (i.e., 24-36 bed volumes/h) and elution velocity up to 40 ml/min (i.e., 48 bed volumes/h) were obtained without compromising the separation efficiency. Its breakthrough capacity was one-third to half that of the commercial DEAE Sepharose Fast Flow media. It was concluded that the novel column is an attractive alternate to traditional axial column.

[Photodynamic inactivation of model virus in human plasma by methylene blue and its influence on plasma proteins]

OBJECTIVE

To determine whether photochemical method can inactivate viruses in human plasma efficiently, and to what extent it affects the protein in human plasma.

METHODS

Vascular stomatitis virus (VSV) Indiana strain was used as the indicating virus. It was inoculated on Vero cell monolayer, incubated in 37 degrees C for 24 hours, microtitered by cytopathogenic effect. Small amount experiments were carried out to observe virus inactivation and the influence on plasma proteins.

RESULTS

Methylene blue (MB) in combination with visible light can inactivate the model virus in human plasma efficiently. The dye in very low concentration combined with light was sufficient to achieve a reduction of VSV titer of more than 6 log10 TCID50. Compared with the untreated plasma, neither the activities of blood clotting factors nor the immunological properties of the plasma proteins and the blood albumin were reduced significantly. In this experiment, the dose of MB used for photoinactivation of the virus was very low, about a hundred fold lower than that of methemoglobinemia used in clinical treatment. Furthermore, heat of the light and photochemical reaction are two import factors for decreasing of clotting factor's activity.

CONCLUSIONS

The results of this preliminary study suggest the potential application of MB-photodynamic inactivation of plasma virus is an useful approach in clinical practice.

[Antiviral activity of antisense oligonucleotides to human cytomegalovirus]

Human cytomegalovirus(HCMV) is one of the important pathogens to human being. At present there is no specific antiviral drugs. In order to find an effective antisense phosphorothioate deoxyoligonucleotide(ASON) against--HCMV, the antiviral activity was observed in this study. Three ASON complementary to UL36 gene were synthesized according to immediate early gene sequence of HCMV, and the antiviral activity was evaluated in vitro using human embryonic lung cells as targeted cells of virus infections. The result showed that ASON targeting to splice donor had fairly strong antiviral activity. The specific ASON has sure antiviral activity. As a new means, it may be used to prevent and treat human CMV infections.