Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 80
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Artigo em Inglês | MEDLINE | ID: mdl-38514461

RESUMO

BACKGROUND AND AIMS: Louse-borne Bartonella quintana infection and flea-borne murine typhus are two potentially serious vector-borne diseases that have led to periodic outbreaks among people experiencing homelessness in the United States. Little is known about louse- and flea-borne disease awareness and prevention among staff who provide services to the population. We surveyed staff in seven US states to identify gaps in knowledge and prevention practices for these diseases. METHODS AND RESULTS: Surveys were administered to 333 staff at 89 homeless shelters and outreach teams in California, Colorado, Georgia, Maryland, Minnesota, New York and Washington from August 2022 to April 2023. Most participants (>68%) agreed that body lice and fleas are a problem for people experiencing homelessness. About half were aware that diseases could be transmitted by these vectors; however, most could not accurately identify which diseases. Less than a quarter of staff could describe an appropriate protocol for managing body lice or fleas. Misconceptions included that clients must isolate or be denied services until they are medically cleared. CONCLUSIONS: Our findings reveal significant knowledge gaps among staff who provide services to people experiencing homelessness in the prevention and control of louse- and flea-borne diseases. This demonstrates an urgent need for staff training to both reduce disease and prevent unnecessary restrictions on services and housing.

2.
ACS Appl Mater Interfaces ; 16(13): 16086-16095, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38506502

RESUMO

Solar water oxidation is a crucial process in light-driven reductive synthesis, providing electrons and protons for various chemical reductions. Despite advances in light-harvesting materials and cocatalysts, achieving high efficiency and stability remains challenging. In this study, we present a simple yet effective strategy for immobilizing natural photosystems (PS) made of abundant and inexpensive elements, using amine-rich polyethylenimine (PEI) hydrogels, to fabricate organic/inorganic hybrid photoanodes. Natural PS II extracted from spinach was successfully immobilized on inverse opal TiO2 photoanodes in the presence of PEI hydrogels, leading to greatly enhanced solar water oxidation activity. Photoelectrochemical (PEC) analyses reveal that PS II can be immobilized in specific orientations through electrostatic interactions between the positively charged amine groups of PEI and the negatively charged stromal side of PS II. This specific orientation ensures efficient photogenerated charge separation and suppresses undesired side reactions such as the production of reactive oxygen species. Our study provides an effective immobilization platform and sheds light on the potential utilization of PS II in PEC water oxidation.

3.
ACS Appl Mater Interfaces ; 16(13): 16767-16777, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38512769

RESUMO

Titanium dioxide (TiO2) nanoparticles are extensively used as a sunscreen filter due to their long-active ultraviolet (UV)-blocking performance. However, their practical use is being challenged by high photochemical activities and limited absorption spectrum. Current solutions include the coating of TiO2 with synthetic polymers and formulating a sunscreen product with additional organic UV filters. Unfortunately, these approaches are no longer considered effective because of recent environmental and public health issues. Herein, TiO2-metal-phenolic network hybrid nanoparticles (TiO2-MPN NPs) are developed as the sole active ingredient for sunscreen products through photochemical suppression and absorption spectrum widening. The MPNs are generated by the complexation of tannic acid with multivalent metal ions, forming a robust coating shell. The TiO2-MPN hybridization extends the absorption region to the high-energy-visible (HEV) light range via a new ligand-to-metal charge transfer photoexcitation pathway, boosting both the sun protection factor and ultraviolet-A protection factor about 4-fold. The TiO2-MPN NPs suppressed the photoinduced reactive oxygen species by 99.9% for 6 h under simulated solar irradiation. Accordingly, they substantially alleviated UV- and HEV-induced cytotoxicity of fibroblasts. This work outlines a new tactic for the eco-friendly and biocompatible design of sunscreen agents by selectively inhibiting the photocatalytic activities of semiconductor nanoparticles while broadening their optical spectrum.

4.
ACS Nano ; 18(1): 451-460, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-37971988

RESUMO

Plasmonic catalysts have the potential to accelerate and control chemical reactions with light by exploiting localized surface plasmon resonances. However, the mechanisms governing plasmonic catalysis are not simple to decouple. Several plasmon-derived phenomena, such as electromagnetic field enhancements, temperature, or the generation of charge carriers, can affect the reactivity of the system. These effects are convoluted with the inherent (nonplasmonic) catalytic properties of the metal surface. Disentangling these coexisting effects is challenging but is the key to rationally controlling reaction pathways and enhancing reaction rates. This study utilizes super-resolution fluorescence microscopy to examine the mechanisms of plasmonic catalysis at the single-particle level. The reduction reaction of resazurin to resorufin in the presence of Au nanorods coated with a porous silica shell is investigated in situ. This allows the determination of reaction rates with a single-molecule sensitivity and subparticle resolution. By variation of the irradiation wavelength, it is possible to examine two different regimes: photoexcitation of the reactant molecules and photoexcitation of the nanoparticle's plasmon resonance. In addition, the measured spatial distribution of reactivity allows differentiation between superficial and far-field effects. Our results indicate that the reduction of resazurin can occur through more than one reaction pathway, being most efficient when the reactant is photoexcited and is in contact with the Au surface. In addition, it was found that the spatial distribution of enhancements varies, depending on the underlying mechanism. These findings contribute to the fundamental understanding of plasmonic catalysis and the rational design of future plasmonic nanocatalysts.

5.
Biomacromolecules ; 24(7): 3043-3050, 2023 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-37283006

RESUMO

Despite the well-known advantages of lipid vesicles for drug and gene delivery, structural instability limits their practical applications and requires strictly regulated conditions for transport and storage. Chemical crosslinking and in situ polymerization have been suggested to increase the membrane rigidity and dispersion stability of lipid vesicles. However, such chemically modified lipids sacrifice the dynamic nature of lipid vesicles and obfuscate their in vivo metabolic fates. Here, we present highly robust multilamellar lipid vesicles through the self-assembly of preformed, cationic large unilamellar vesicles (LUVs) with hydrolyzed collagen peptides (HCPs). The cationic LUVs undergo vesicle-to-vesicle attachment and structural reorganization through polyionic complexation with HCPs, resulting in the formation of multilamellar collagen-lipid vesicles (MCLVs). The resulting MCLVs exhibit excellent structural stability against variations in pH and ionic strength and the addition of surfactants. Particularly, the MCLVs maintain their structural stability against repeated freeze-thaw stresses, proving the unprecedented stabilization effect of biological macromolecules on lipid lamellar structures. This work provides a practically attractive technique for the simple and quick fabrication of structurally robust lipid nanovesicles without covalent crosslinkers, organic solvents, and specialized instruments.


Assuntos
Tensoativos , Lipossomas Unilamelares , Lipossomas Unilamelares/química , Tensoativos/química , Cátions , Lipídeos/química , Peptídeos , Lipossomos/química
6.
Work ; 76(1): 243-249, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36872817

RESUMO

BACKGROUND: Oral and maxillofacial surgeons (OMS) are continually required to adjust position and posture to access the limited surgical field in and around the head and neck, oral cavity, and oropharynx. Very limited data exists that quantifies the burden of musculoskeletal disorders (MSD) among OMS. OBJECTIVE: This exploratory study seeks to address these literature gaps by assessing the prevalence of MSD among OMS. METHOD: A 12-question survey was designed to investigate the prevalence of MSD for OMS, including residents in training, actively practicing surgeons, and retired surgeons. Seventy-six surveys were distributed and completed in person by surgeons attending professional conferences from September 2018-September 2019. Survey questions included the Baker-Wong Faces pain scale, years in practice, number of hours worked per week, job tenure, pain attributable to work, and age. The Nordic scale identified and delineated anatomic site of musculoskeletal complaints, duration and treatment sought. RESULTS: The most frequently cited sources and locations of pain attributable to occupation were shoulders, neck, and lower back. The risk of MSD symptoms was relatively two-fold [PR = 2.54, 95% CI = 0.90, 7.22] among OMS in practice for more than ten years compared to those in practice less than ten years. After adjusting for age and hours worked per week as potential confounders, the risk of MSD symptoms was higher among OMS in practice for more than ten years compared to those with less than ten years of experience, despite no statistically significant association. CONCLUSION: OMS are impacted by a high prevalence of MSD. The neck, shoulder, and lower back are the most frequently affected with discomfort and pain. This study found that practicing oral and maxillofacial surgery for more than 10 years is a potential risk factor for experiencing MSD.


Assuntos
Doenças Musculoesqueléticas , Doenças Profissionais , Cirurgiões , Humanos , Cirurgiões Bucomaxilofaciais , Doenças Profissionais/epidemiologia , Doenças Profissionais/prevenção & controle , Doenças Profissionais/etiologia , Doenças Musculoesqueléticas/epidemiologia , Doenças Musculoesqueléticas/etiologia , Doenças Musculoesqueléticas/prevenção & controle , Inquéritos e Questionários , Fatores de Risco , Dor , Prevalência
7.
J Mater Chem B ; 11(13): 2904-2915, 2023 03 30.
Artigo em Inglês | MEDLINE | ID: mdl-36892061

RESUMO

Polymer coatings containing both fouling-resistant and fouling-release components have been reported to show synergistic antifouling properties. However, it remains unclear how the polymer composition influences the antifouling performance, particularly regarding foulants of different sizes and biological natures. Herein, we prepare dual functionalized brush copolymers containing fouling-resistant poly(ethylene glycol) (PEG) and fouling-release polydimethylsiloxane (PDMS) and examine their antifouling performances against different biofoulants. We utilize poly(pentafluorophenyl acrylate) (PPFPA) as a reactive precursor polymer and graft amine-functionalized PEG and PDMS side chains to create PPFPA-g-PEG-g-PDMS brush copolymers of systematically varying compositions. The copolymer films spin-coated on silicon wafers exhibit surface heterogeneity that can be correlated well with the bulk composition of the copolymer. When the copolymer-coated surfaces are examined against protein (human serum albumin and bovine serum albumin) adsorption and cell (lung cancer cells and microalgae) adhesion, they are found to perform better than the homopolymers. The enhanced antifouling properties are attributed to the copolymers having a PEG-rich top layer and a PEG/PDMS mixed bottom layer that work synergistically to resist biofoulant attachment. Furthermore, the composition of the best-performing copolymer is different for different foulants, with PPFPA-g-PEG39-g-PDMS46 exhibiting the best antifouling properties against proteins and PPFPA-g-PEG54-g-PDMS30 exhibiting the best antifouling properties against cells. We explain this difference by considering the changes in the length scale of the surface heterogeneity in relation to the foulant sizes.


Assuntos
Incrustação Biológica , Humanos , Incrustação Biológica/prevenção & controle , Polímeros/farmacologia , Polímeros/química , Polietilenoglicóis/química , Soroalbumina Bovina/química , Adsorção
8.
J Mater Chem B ; 11(10): 2135-2144, 2023 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-36762491

RESUMO

This study introduces a multilamellar ceramide core-structured microvehicle platform for substantial skin barrier function recovery. Our approach essentially focused on fabricating bacterial cellulose nanofiber (BCNF)-enveloped ceramide-rich lipid microparticles (CerMPs) by solidifying BCNF-armored oil-in-water Pickering emulsions. The oil drops consisted of Ceramide NP (a phytosphingosine backbone N-acylated with a saturated stearic acid) and fatty alcohols (FAs) with a designated stoichiometry. The thin BCNF shell layer completely blocked the growth of ceramide molecular crystals from the CerMPs for a long time. The CerMP cores displayed a multilamellar structure wherein the interlayer distance and lateral packing could be manipulated using FAs with different alkyl chain lengths. The CerMPs remarkably lowered the trans-epidermal water loss while restoring the structural integrity of the epidermis in damaged skin. The results obtained herein highlight that the CerMP system provides a practical methodology for developing various types of skin-friendly formulations that can strengthen the skin barrier function.


Assuntos
Ceramidas , Pele , Ceramidas/química , Recuperação de Função Fisiológica , Epiderme , Água/química
9.
Adv Healthc Mater ; 12(9): e2202076, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36579651

RESUMO

Rapid, sensitive, specific, and user-friendly microRNA (miRNA) assays are in high demand for point-of-care diagnosis. Target-catalyzed toehold-mediated strand displacement (TMSD) has received increasing attention as an enzyme-free molecular tool for DNA detection. However, the application of TMSD to miRNA targets is challenging because relatively weak DNA/RNA hybridization leads to failure in the subtle kinetic control of multiple hybridization steps. Here, a simple method is presented for miRNA assay based on the one-pot self-assembly of Y-shaped DNAs with streptavidin via an miRNA-catalyzed TMSD cascade reaction. A single miRNA catalyzes the opening cycle of DNA hairpin loops to generate multiple Y-shaped DNAs carrying biotin and a quencher at the end of their arms. Introducing a single base-pair mismatch near the toehold facilitates RNA-triggered strand displacement while barely disturbing nonspecific reactions. The Y-shaped DNAs are self-assembled with fluorescently labeled streptavidin (sAv), which produces nanoscale DNA-sAv nanogel particles mediating efficient Förster resonance energy transfer in their 3D network. The enhancing effect dramatically reduces the detection limit from the nanomolar level to the picomolar level. This work proves that TMSD-based DNA nanogel with a base-pair mismatch incorporated to a hairpin structure is a promising approach towards sensitive and accurate miRNA assay.


Assuntos
Técnicas Biossensoriais , MicroRNAs , MicroRNAs/genética , Estreptavidina , Nanogéis , DNA/química , Catálise , Técnicas Biossensoriais/métodos
10.
J Occup Environ Med ; 64(11): e714-e721, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-36069858

RESUMO

BACKGROUND: Firefighters are at high-risk of mental health. This study qualitatively assessed the pathways toward mental health in firefighters. METHODS: A two-phased assessment was conducted incorporating in-depth interviews (n = 52) and 10 focus group discussions (n = 82) with firefighters. Thematic analysis was used to develop codes and themes that informed the development of a conceptual model. RESULTS: Firefighters recognized personalizing events by relating calls to their personal lives or prior life experiences as the main risk factor. Department debriefing with fire chiefs or leadership after traumatic events was reported as the primary coping strategy firefighters found most effective. Stigma and lack of medical professionals understanding the firefighter culture were identified as barriers for accessing mental health services or their effectiveness. DISCUSSION: Pathways toward mental health in firefighters were identified that could be used to improve current strategies to protect their well-being.


Assuntos
Bombeiros , Serviços de Saúde Mental , Humanos , Bombeiros/psicologia , Saúde Mental , Adaptação Psicológica , Grupos Focais
11.
J Photochem Photobiol B ; 235: 112565, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36113261

RESUMO

Photochemical instability and reactivity of organic ultraviolet (UV) filters not only degrade the performance of sunscreen formulations but also generate toxic photodegradation products and reactive oxygen species (ROS). Although the encapsulation of organic UV filters into synthetic polymer particles has been widely investigated, synthetic plastics were recently banned for personal care and cosmetic products due to marine and coastal pollution issues. Here we present a plastic-free, photochemically stable and inactive UV filter platform based on chitosan-coated mesoporous silica microparticles, denoted 'mSOCPs', incorporating octyl methoxycinnamate (OMC) as a sunscreen agent. Sunlight induced the degradation of ∼80% free OMC in artificial sweat in 1 h at room temperature, while only 20% of OMC degraded for 3 h when encapsulated within mSOCPs. Moreover, mSOCPs efficiently suppressed the photochemical generation of ROS by about 99% through the combined effects of the mesoporous silica structure and chitosan coating. Accordingly, mSOCPs substantially increased the cell viability of fibroblasts exposed to UV irradiation. This work demonstrates that the biopolymer coatings of mesoporous inorganic particles can be a promising approach to the plastic-free encapsulation of organic UV filters for suppressing their photochemical reactivity and degradation.


Assuntos
Quitosana , Protetores Solares , Estabilidade de Medicamentos , Espécies Reativas de Oxigênio , Dióxido de Silício/química , Protetores Solares/química , Protetores Solares/farmacologia , Raios Ultravioleta
12.
Adv Mater ; 34(35): e2200408, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35799313

RESUMO

Biological systems consist of hierarchical protein structures, each of which has unique 3D geometries optimized for specific functions. In the past decades, the growth of inorganic materials on specific proteins has attracted considerable attention. However, the use of specific proteins as templates has only been demonstrated in relatively simple organisms, such as viruses, limiting the range of structures that can be used as scaffolds. This study proposes a method for synthesizing metallic structures that resemble the 3D assemblies of specific proteins in mammalian cells and animal tissues. Using 1.4 nm nanogold-conjugated antibodies, specific proteins within cells and ex vivo tissues are labeled, and then the nanogold acts as nucleation sites for growth of metal particles. As proof of concept, various metal particles are grown using microtubules in cells as templates. The metal-containing cells are applied as catalysts and show catalytic stability in liquid-phase reactions due to the rigid support provided by the microtubules. Finally, this method is used to produce metal structures that replicate the specific protein assemblies of neurons in the mouse brain or the extracellular matrices in the mouse kidney and heart. This new biotemplating approach can facilitate the conversion of specific protein structures into metallic forms in ex vivo multicellular organisms.


Assuntos
Mamíferos , Metais , Animais , Catálise , Metais/química , Camundongos
13.
Biosens Bioelectron ; 210: 114288, 2022 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-35460968

RESUMO

Rapid, sensitive, and reliable nucleic acid assay is crucial for the molecular diagnosis of many diseases. For high sensitivity, conventional techniques require time-consuming, high-cost, and complicated procedures, such as enzymatic gene amplification, labeling, and purification, limiting their applications to point-of-care diagnostics. Herein we report a new DNA nanoprobe based on the dual effects of target-specific plasmon-enhanced fluorescence and off-target plasmonic quenching. Janus gold half-shell/polystyrene nanospheres (hsAu/PSs, ∼150 nm diameter) are tethered with capture single-stranded DNA (ssDNA), coupled with a fluorophore-conjugated reporter ssDNA through sandwich-type hybridization with target DNA, resulting in 5-fold increase through plasmon-enhanced fluorescence. Smaller gold nanoparticles (∼13 nm diameter) are subsequently introduced as quenchers to reduce background fluorescence from unhybridized reporter ssDNA, increasing the sensitivity about 103 times. The limit of detection of the dual-mode plasmonic DNA nanoprobe is 16 pM at room temperature in 1 h for the target gene of Klebsiella pneumoniae carbapenemase. The nanoprobe also exhibits a high selectivity enough to discriminate a single-base difference in the target gene. Our strategy harnesses both of the plasmon-mediated fluorescence enhancement and quenching effects through the sophisticated design of nanoscale colloids, which opens a promising avenue to the enzyme-free, simple, sensitive, and selective detection of pathogenic DNA.


Assuntos
Técnicas Biossensoriais , Nanopartículas Metálicas , Técnicas Biossensoriais/métodos , DNA , DNA de Cadeia Simples , Ouro , Hibridização de Ácido Nucleico
14.
J Interpers Violence ; 37(17-18): NP15992-NP16012, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-34144668

RESUMO

Bias-based bullying (e.g., bullying related to race, weight, sexual orientation) is a common experience among youth, yet few school-based prevention programs explicitly address this type of bullying. This study explores whether schools that offer diversity education activities have lower rates of bias-based bullying among students compared to schools that do not offer these activities. Data came from two sources: the 2018 CDC School Profiles Survey (N = 216 schools) and the 2019 Minnesota Student Survey (N = 64,510 students). Multilevel logistic regression tested associations between diversity education activities (diversity clubs, lessons, or special events) and eight types of bias-based bullying among students, with attention to effect modification by relevant demographic characteristics. Students attending schools that offer a wider variety of diversity education opportunities had significantly lower odds of bullying about race, ethnicity, or national origin among boys of color (OR = 0.89, CI: 0.80, 1.00), about sexual orientation for gay, bisexual, and questioning boys (OR = 0.81, CI: 0.67, 0.97), and about disability for boys with a physical health problem (OR = 0.86, CI: 0.76, 0.99). Attending a school with more types of diversity education activities may protect vulnerable students against specific types of bias-based bullying and advance health equity. A diversity education is recommended as a key component of antibullying efforts and policy.


Assuntos
Bullying , Minorias Sexuais e de Gênero , Adolescente , Bissexualidade , Feminino , Humanos , Masculino , Instituições Acadêmicas , Estudantes
15.
Adv Healthc Mater ; 10(22): e2101239, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34467659

RESUMO

Various lipid-based nanocarriers have been developed for the co-delivery of protein antigens with immunological adjuvants. However, their in vivo potency in vaccine delivery is limited by structural instability, which causes off-target delivery and low cross-presentation efficacies. Recent works employ covalent cross-linking to stabilize the lipid nanostructures, though the immunogenicity and side effects of chemically modified protein antigens and lipids can cause a long-lasting safety issue. Here robust "conjugation-free" multilamellar protein antigen-lipid hybrid nanovesicles (MPLVs) are introduced through the antigen-mediated self-assembly of unilamellar lipid vesicles for the co-delivery of protein antigens and immunologic adjuvants. The nanocarriers coated with monophosphoryl lipid A and hyaluronic acids elicit highly increase antigen-specific immune responses in vitro and in vivo. The MPLVs increase the generation of immunological surface markers and cytokines in mouse-derived bone-marrow dendritic cells compared to soluble antigens with adjuvants. Besides, the vaccination of mice with the MPLVs significantly increase the production of anti-antigen antibody and interferon-gamma via the activation of CD4+ and CD8+ T cells, respectively. These findings suggest that MPLVs can serve as a promising nanovaccine delivery platform for efficient antigen cross-presentation through the efficient co-delivery of protein antigens with adjuvants.


Assuntos
Linfócitos T CD8-Positivos , Nanopartículas , Adjuvantes Imunológicos , Animais , Apresentação de Antígeno , Antígenos , Células Dendríticas , Lipídeos , Camundongos , Camundongos Endogâmicos C57BL , Ovalbumina
16.
ACS Biomater Sci Eng ; 7(8): 3783-3792, 2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34324295

RESUMO

Heterogeneous tissue models require the assembly and co-culture of multiple types of cells. Our recent work demonstrated taste signal transmission from gustatory cells to neurons by grafting single-stranded DNA into the cell membrane to construct multicellular assemblies. However, the weak DNA linkage and low grafting density allowed the formation of large gustatory cell self-aggregates that cannot communicate with neurons efficiently. This article presents the construction of artificial taste buds exhibiting active intercellular taste signal transmission through the hybridization of gustatory-neuronal multicellular interfaces using bioorthogonal click chemistry. Hybrid cell clusters were formed by the self-assembly of neonatal gustatory cells displaying tetrazine with a precultured embryonic hippocampal neuronal network displaying trans-cyclooctene. A bitter taste signal transduction was provoked in gustatory cells using denatonium benzoate and transmitted to neurons as monitored by intracellular calcium ion sensing. In the multicellular hybrids, the average number of signal transmissions was five to six peaks per cell, and the signal transmission lasted for ∼5 min with a signal-to-signal gap time of 10-40 s. The frequent and extended intercellular signal transmission suggests that the cell surface modification by the bioorthogonal click chemistry is a promising approach to fabricating functional multicellular hybrid clusters potentially useful for cell-based biosensors, toxicity assays, and tissue regeneration.


Assuntos
Papilas Gustativas , Técnicas de Cocultura , Neurônios , Transdução de Sinais , Paladar
17.
Biosens Bioelectron ; 182: 113110, 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-33812283

RESUMO

Fast, sensitive, specific, and user-friendly DNA assay is a key technique for the next generation point-of-care molecular diagnosis. However, high-cost, time-consuming, and complicated enzyme-based DNA amplification step is essential to achieve high sensitivity. Herein, a short target DNA-catalyzed formation of quantum dot (QD)-DNA hydrogel is proposed as a new DNA assay platform satisfying the above requirements. A single-stranded target DNA catalyzes the opening cycle of DNA hairpin loops, which are quickly self-assembled with DNA-functionalized QDs to generate QD-DNA hydrogel. The three-dimensional hydrogel network allows efficient resonance energy transfer, dramatically lowering the limit of detection down to ~6 fM without enzymatic DNA amplification. The QD-DNA hydrogel also enables a rapid detection (1 h) with high specificity even for a single-base mismatch. The clinical applicability of the QD-DNA hydrogel is demonstrated for the Klebsiella pneumoniae carbapenemase gene, one of the key targets of drug-resistant pathogenic bacteria.


Assuntos
Técnicas Biossensoriais , Pontos Quânticos , Catálise , DNA/genética , Transferência Ressonante de Energia de Fluorescência , Hidrogéis
18.
J Control Release ; 331: 187-197, 2021 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-33422501

RESUMO

Protein encapsulation into nanocarriers has been extensively studied to improve the efficacy and stability of therapeutic proteins. However, the chemical modification of proteins or new synthetic carrier materials are essential to achieve a high encapsulation efficiency and structural stability of proteins, which hinders their clinical applications. New strategies to physically incorporate proteins into nanocarriers feasible for clinical uses are required to overcome the current limitation. Here we report the spontaneous protein-induced reorganization of 'pre-formed' unilamellar lipid vesicles to efficiently incorporate proteins within multilamellar protein-lipid hybrid vesicles without chemical modification. Epidermal growth factor (EGF) binds to the surface of cationic unilamellar lipid vesicles and induces layer-by-layer self-assembly of the vesicles. The protein is spontaneously entrapped in the interstitial layers of a multilamellar structure with extremely high loading efficiency, ~99%, through polyionic interactions as predicted by molecular dynamics simulation. The loaded protein exhibits much higher structural, chemical, and biological stability compared to free protein. The method is also successfully applied to several other proteins. This work provides a promising method for the highly efficient encapsulation of therapeutic proteins into multilamellar lipid vesicles without the use of specialized instruments, high energy, coupling agents, or organic solvents.


Assuntos
Lipossomos , Lipossomas Unilamelares , Cátions , Lipídeos , Solventes
19.
ACS Nano ; 14(12): 17693-17703, 2020 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-33270433

RESUMO

Deterministic positioning and assembly of colloidal nanoparticles (NPs) onto substrates is a core requirement and a promising alternative to top-down lithography to create functional nanostructures and nanodevices with intriguing optical, electrical, and catalytic features. Capillary-assisted particle assembly (CAPA) has emerged as an attractive technique to this end, as it allows controlled and selective assembly of a wide variety of NPs onto predefined topographical templates using capillary forces. One critical issue with CAPA, however, lies in its final printing step, where high printing yields are possible only with the use of an adhesive polymer film. To address this problem, we have developed a template dissolution interfacial patterning (TDIP) technique to assemble and print single colloidal AuNP arrays onto various dielectric and conductive substrates in the absence of any adhesion layer, with printing yields higher than 98%. The TDIP approach grants direct access to the interface between the AuNP and the target surface, enabling the use of colloidal AuNPs as building blocks for practical applications. The versatile applicability of TDIP is demonstrated by the creation of direct electrical junctions for electro- and photoelectrochemistry and nanoparticle-on-mirror geometries for single-particle molecular sensing.

20.
ACS Appl Mater Interfaces ; 12(30): 33817-33826, 2020 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-32638585

RESUMO

Hybridization of homogeneous catalytic sites with a photoelectrode is an attractive approach to highly selective and tunable photocatalysis using heterogeneous platforms. However, weak and unclear surface chemistry often leads to the dissociation and irregular orientation of catalytic centers, restricting long-term usability with high selectivity. Well-defined and robust ligands that can persist under harsh photocatalytic conditions are essential for the success of hybrid-type photocatalysis. Here, we introduce N-heterocyclic carbene as a durable linker for the immobilization of a Rubpy complex-based CO2 reduction site (cis-dichloro-(4,4'-diphosphonato-Rubpy)(p-cymene) (RuCY)) on a p-type gallium nitride/gold nanoparticle (p-GaN/AuNP) heterostructure. The p-GaN/AuNPs/RuCY photocathode was coupled with a hematite photoanode to drive photoelectrochemical CO2 reduction along with water oxidation. Highly selective CO2 reduction into formates, up to 98.2%, was achieved utilizing plasmonic hot electrons accumulated on AuNPs. The turnover frequency was 1.46 min-1 with a faradic efficiency of 96.8% under visible light illumination (243 mW·cm-2). This work demonstrates that the N-heterocyclic carbene-mediated surface functionalization with homogeneous catalytic sites is a promising approach to increase the sustainability and usability of hybrid catalysts.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...