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1.
Nat Biomed Eng ; 4(5): 518-530, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32313101

RESUMO

The detection and quantification of low-abundance molecular biomarkers in biological samples is challenging. Here, we show that a plasmonic nanoscale construct serving as an 'add-on' label for a broad range of bioassays improves their signal-to-noise ratio and dynamic range without altering their workflow and readout devices. The plasmonic construct consists of a bovine serum albumin scaffold with approximately 210 IRDye 800CW fluorophores (with a fluorescence intensity approximately 6,700-fold that of a single 800CW fluorophore), a polymer-coated gold nanorod acting as a plasmonic antenna and biotin as a high-affinity biorecognition element. Its emission wavelength can be tuned over the visible and near-infrared spectral regions by modifying its size, shape and composition. It improves the limit of detection in fluorescence-linked immunosorbent assays by up to 4,750-fold and is compatible with multiplexed bead-based immunoassays, immunomicroarrays, flow cytometry and immunocytochemistry methods, and it shortens overall assay times (to 20 min) and lowers sample volumes, as shown for the detection of a pro-inflammatory cytokine in mouse interstitial fluid and of urinary biomarkers in patient samples.

2.
ACS Appl Mater Interfaces ; 12(5): 5420-5428, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31913006

RESUMO

Implantable and wearable biosensors that enable monitoring of biophysical and biochemical parameters over long durations are highly attractive for early and presymptomatic diagnosis of pathological conditions and timely clinical intervention. Poor stability of antibodies used as biorecognition elements and the lack of effective methods to refresh the biosensors upon demand without severely compromising the functionality of the biosensor remain significant challenges in realizing protein biosensors for long-term monitoring. Here, we introduce a novel method involving organosilica encapsulation of antibodies for preserving their biorecognition capability under harsh conditions, typically encountered during the sensor refreshing process, and elevated temperature. Specifically, a simple aqueous rinsing step using sodium dodecyl sulfate (SDS) solution refreshes the biosensor by dissociating the antibody-antigen interactions. Encapsulation of the antibodies with an organosilica layer is shown to preserve the biorecognition capability of otherwise unstable antibodies during the SDS treatment, thus ultimately facilitating the refreshability of the biosensor over multiple cycles. Harnessing this method, we demonstrate the refreshability of plasmonic biosensors for anti-IgG (model bioanalyte) and neutrophil gelatinase-associated lipocalin (NGAL) (a biomarker for acute and chronic kidney injury). The novel encapsulation approach demonstrated can be easily extended to other transduction platforms to realize refreshable biosensors for monitoring of protein biomarkers over long durations.

3.
Chem Soc Rev ; 49(3): 983-1031, 2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-31960001

RESUMO

Biological photonic structures can precisely control light propagation, scattering, and emission via hierarchical structures and diverse chemistry, enabling biophotonic applications for transparency, camouflaging, protection, mimicking and signaling. Corresponding natural polymers are promising building blocks for constructing synthetic multifunctional photonic structures owing to their renewability, biocompatibility, mechanical robustness, ambient processing conditions, and diverse surface chemistry. In this review, we provide a summary of the light phenomena in biophotonic structures found in nature, the selection of corresponding biopolymers for synthetic photonic structures, the fabrication strategies for flexible photonics, and corresponding emerging photonic-related applications. We introduce various photonic structures, including multi-layered, opal, and chiral structures, as well as photonic networks in contrast to traditionally considered light absorption and structural photonics. Next, we summarize the bottom-up and top-down fabrication approaches and physical properties of organized biopolymers and highlight the advantages of biopolymers as building blocks for realizing unique bioenabled photonic structures. Furthermore, we consider the integration of synthetic optically active nanocomponents into organized hierarchical biopolymer frameworks for added optical functionalities, such as enhanced iridescence and chiral photoluminescence. Finally, we present an outlook on current trends in biophotonic materials design and fabrication, including current issues, critical needs, as well as promising emerging photonic applications.


Assuntos
Materiais Biomiméticos/química , Biopolímeros/química , Nanoestruturas/química , Animais , Produtos Biológicos/química , Membranas Artificiais , Estrutura Molecular , Óptica e Fotônica , Processos Fotoquímicos , Proteínas/química , Relação Estrutura-Atividade
4.
Kidney Int ; 96(6): 1417-1421, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31668633

RESUMO

Renal cell carcinoma (RCC) has poor survival prognosis because it is asymptomatic at an early, more curative stage. Recently, urine perilipin-2 (PLIN-2) was demonstrated to be a sensitive and specific biomarker for the noninvasive, early detection of RCC and an indispensable indicator to distinguish cancer from a benign renal mass. However, current Western blot or ELISA PLIN-2 assays are complicated, expensive, time-consuming or insensitive, making them unsuitable for routine analysis in clinical settings. Here we developed a plasmonic biosensor based on the high refractive index sensitivity of gold nanorattles for the rapid detection of PLIN-2 in patient urine. The paper-based plasmonic assay is highly sensitive and has a dynamic range of 50 pg/ml to 5 µg/ml PLIN-2. The assay is not compromised by variations in urine pH or high concentrations of interfering proteins such as albumin and hemoglobin, making it an excellent candidate for routine clinical applications. The urine PLIN-2 assay readily distinguished patients with pathologically proven clear cell carcinomas of various size, stage and grade (55.9 [39.5, 75.8] ng/ml, median [1st and 3rd quartile]) from age-matched controls (0.3 [0.3, 0.5] ng/ml), patients with bladder cancer (0.5 [0.4, 0.6] ng/ml) and patients with diabetic nephropathy (0.6 [0.4, 0.7] ng/ml). Urine PLIN-2 concentrations were roughly proportional to tumor size (Pearson coefficient 0.59). Thus, this cost-effective and label-free method represents a novel approach to conduct a non-invasive population screen or rapid differential diagnosis of imaged renal masses, significantly facilitating the early detection and diagnosis of RCC.

5.
ACS Appl Mater Interfaces ; 11(41): 37939-37946, 2019 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-31525866

RESUMO

Electromagnetic hotspots at the interstices of plasmonic assemblies are recognized to be the most potent sites for surface-enhanced Raman scattering (SERS). We demonstrate a novel "add-on" electromagnetic hotspot formation technique, which significantly improves the sensitivity of conventional SERS substrates composed of individual plasmonic nanostructures. The novel approach demonstrated here involves the transfer of "plasmonic patch", a transparent, flexible, and conformal elastomeric film adsorbed with plasmonic nanostructures, onto a conventional SERS substrate. The addition of the plasmonic patch onto a conventional SERS substrate following the analyte capture results in the formation of electromagnetic hotspots and hence a large SERS enhancement. The application of the plasmonic patch improves the sensitivity and limit of detection of conventional SERS substrates by up to ∼100-fold. The transfer of the plasmonic patch also effectively transforms the SERS-inactive gold mirror to a highly SERS-active "particle-on-mirror" system. Furthermore, we demonstrate that the "add-on" technique can be effectively utilized for the vapor-phase detection of explosives such as trinitrotoluene (TNT) using peptide recognition elements. We believe that the on-demand hotspot formation approach presented here represents a highly versatile and ubiquitously applicable technology readily expandable to any existing SERS substrate without employing complicated modification.

6.
Acc Chem Res ; 52(5): 1215-1225, 2019 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-31062969

RESUMO

In meeting the increasing need for clean water in both developing and developed countries and in rural and urban communities, photothermal membrane water treatment technologies provide outstanding advantages: For developing countries and rural communities, by utilizing sunlight, photothermal membrane water treatment provides inexpensive, convenient, modular, decentralized, and accessible ways to clean water, which can reduce the consumption of conventional energy (e.g., electricity, natural gas) and the cost of clean water production. In developed countries and urban communities, photothermal membrane water treatment can improve the energy efficiency during water purification. In these water purification processes, the light absorption and light-to-heat conversion of photothermal materials are important factors in determining the membrane efficacy. Nanomaterials with well-controlled structure and optical properties can increase the light absorption and photothermal conversion of newly developed membranes. This Account introduces our recent work on developing scalable, cost-effective, and highly efficient photothermal membranes for four water purification applications: reverse osmosis (RO), ultrafiltration (UF), solar steam generation (SSG), and photothermal membrane distillation (PMD). By utilizing photothermal materials, first, we have demonstrated how sunlight can be used to improve the membrane's resistance to biofouling in RO and UF processes by photothermally induced inactivation of microorganisms. Second, we have developed novel SSG membranes (i.e., interfacial evaporators) that can harvest solar energy, convert it to localized heat, and generate clean water by evaporation. This desalination approach is particularly useful and promising for treatment of highly saline water. These new interfacial evaporators utilized graphene oxide (GO), reduced graphene oxide (RGO), molybdenum disulfide (MoS2), and polydopamine (PDA). The solar conversion efficiency and environmental sustainability of the interfacial evaporators were optimized via (i) novel and versatile bottom-up biofabrication (e.g., incorporation of photothermal materials during bacterial nanocellulose (BNC) growth) and (ii) easy and cost-effective top-down preparation (e.g., modification of natural wood with photothermal materials). Third, we have developed membranes for PMD that incorporate photothermal materials to generate heat under solar irradiation, thus providing a higher transmembrane temperature difference and higher driving force for effective vapor transport, making the membrane distillation process more energy-efficient. Lastly, this Account compares the photothermal membrane applications, summarizes current challenges for photothermal membrane applications, and offers future directions to facilitate the translation of photothermal membranes from the laboratory to large engineered systems by improving their scalability, stability, and sustainability.

7.
ACS Sens ; 4(6): 1569-1576, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-31070358

RESUMO

Minimally invasive devices to detect molecules in dermal interstitial fluid (ISF) are desirable for point-of-care diagnostic and monitoring applications. In this study, we developed a microneedle (MN) patch that collects ISF for on-patch biomarker analysis by surface-enhanced Raman scattering (SERS). The micrometer-scale MNs create micropores in the skin surface, through which microliter quantities of ISF are collected onto plasmonic paper on the patch backing. The plasmonic paper was prepared by immobilizing poly(styrenesulfonate) (PSS) coated gold nanorods (AuNRs) on a thin strip of filter paper using plasmonic calligraphy. Negatively charged PSS was used to bind positively charged rhodamine 6G (R6G), which served as a model compound, and thereby localize R6G on AuNR surface. R6G bound on the AuNR surface was detected and quantified by acquiring SERS spectra from the plasmonic paper MN patch. This approach was used to measure pharmacokinetic profiles of R6G in ISF and serum from rats in vivo. This proof-of-concept study indicates that a plasmonic paper MN patch has the potential to enable on-patch measurement of molecules in ISF for research and future medical applications.

8.
J Biomech Eng ; 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31141589

RESUMO

Giant unilamellar vesicles (GUVs) and supported lipid bilayers (SLBs) are synthetic model systems widely used in biophysical studies of lipid membranes. Although SLBs are advantageous for biophysical analysis, phase separation behaviors of lipid species in these two model systems can differ due to the lipid-substrate interactions that are present only for SLBs. In the present study, we report that in binary systems, certain phase domains on GUVs retain their original shapes and patterns after the GUVs rupture on glass surfaces. This enabled atomic force microscopy (AFM) experiments on phase domains, a procedure difficult to perform and interpret when applied to GUVs. Unusual phase behavior was evident in binary GUVs containing DLPC and either DPPC or DSPC. These DLPC/DSPC and DLPC/DPPC GUVs both presented the thermodynamic anomaly of having two co-existing gel phases. One phase (a bright phase) included a relatively high concentration of DiI-C20 but excluded Bodipy-HPC, and the other (dark phase) excluded both probes. The bright phases are of interest because they seem to stabilize dark phases against coalescence. Results suggested that the gel phases labeled by DiIC20 in the DLPC/DSPC membrane, which surround the dark gel phase, is an extra layer of membrane, indicating a highly curved structure that might stabilize the interior dark domains, thereby enabling the co-existence of two different gel phases. Results show the utility of AFM on collapsed GUVs, and suggest a possible mechanism for stabilization of lipid domains.

9.
ACS Appl Mater Interfaces ; 11(5): 5499-5508, 2019 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-30640448

RESUMO

Microcapsules are emerging as promising microsize drug carriers due to their remarkable deformability. Shape plays a dominant role in determining their vascular transportation. Herein, we explored the effect of the shape of the microcapsules on the in vivo biodistribution for rational design of microcapsules to achieve optimized targeting efficiency. Silk fibroin, a biocompatible, biodegradable, and abundant material, was utilized as a building block to construct biconcave discoidal and spherical microcapsules with diameter of 1.8 µm and wall thickness of 20 nm. We have compared the cytocompatibility, cellular uptake, and biodistribution of both microcapsules. Both biconcave and spherical microcapsules exhibited excellent cytocompatibility and internalization into cancer cells. During blood circulation in mice, both microcapsules showed retention in liver and kidney and most underwent renal clearance. However, we observed significantly higher accumulation of biconcave silk microcapsules in lung compared with spherical microcapsules, and the accumulation was found to be stable in lung even after 3 days. The higher concentration of biconcave discoidal microcapsules found in lung arises from pulmonary environment, margination dynamics, and enhanced deformation in bloodstream. Red blood cell (RBC)-mimicking silk microcapsules demonstrated here can potentially serve as a promising platform for delivering drugs for lung diseases.


Assuntos
Cápsulas/química , Cápsulas/farmacocinética , Portadores de Fármacos/química , Portadores de Fármacos/farmacocinética , Fibroínas/química , Fibroínas/farmacocinética , Administração Intravenosa , Animais , Cápsulas/administração & dosagem , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Portadores de Fármacos/administração & dosagem , Portadores de Fármacos/toxicidade , Eritrócitos/citologia , Fibroínas/administração & dosagem , Células Endoteliais da Veia Umbilical Humana , Humanos , Rim/química , Rim/metabolismo , Fígado/química , Fígado/metabolismo , Pulmão/química , Pulmão/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Distribuição Tecidual
10.
Environ Sci Technol ; 53(1): 412-421, 2019 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-30215517

RESUMO

Biofouling poses one of the most serious challenges to membrane technologies by severely decreasing water flux and driving up operational costs. Here, we introduce a novel anti-biofouling ultrafiltration membrane based on reduced graphene oxide (RGO) and bacterial nanocellulose (BNC), which incoporates GO flakes into BNC in situ during its growth. In contrast to previously reported GO-based membranes for water treatment, the RGO/BNC membrane exhibited excellent aqueous stability under environmentally relevant pH conditions, vigorous mechanical agitation/sonication, and even high pressure. Importantly, due to its excellent photothermal property, under light illumination, the membrane exhibited effective bactericidal activity, obviating the need for any treatment of the feedwater or external energy. The novel design and in situ incorporation of the membranes developed in this study present a proof-of-concept for realizing new, highly efficient, and environmental-friendly anti-biofouling membranes for water purification.


Assuntos
Incrustação Biológica , Grafite , Membranas Artificiais , Óxidos , Ultrafiltração
11.
Adv Healthc Mater ; 7(22): e1800950, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30369102

RESUMO

Protein therapeutics are prone to lose their structure and bioactivity under various environmental stressors. This study reports a facile approach using a nanoporous material, zeolitic imidazolate framework-8 (ZIF-8), as an encapsulant for preserving the prototypic protein therapeutic, insulin, against different harsh conditions that may be encountered during storage, formulation, and transport, including elevated temperatures, mechanical agitation, and organic solvent. Both immunoassay and spectroscopy analyses demonstrate the preserved chemical stability and structural integrity of insulin offered by the ZIF-8 encapsulation. Biological activity of ZIF-8-preserved insulin after storage under accelerated degradation conditions (i.e., 40 °C) is evaluated in vivo using a diabetic mouse model, and shows comparable bioactivity to refrigeration-stored insulin (-20 °C). It is also demonstrated that ZIF-8-preserved insulin has low cytotoxicity in vitro and does not cause side effects in vivo. Furthermore, ZIF-8 residue can be completely removed by a simple purification step before insulin administration. This biopreservation approach is potentially applicable to diverse protein therapeutics, thus extending the benefits of advanced biologics to resource-limited settings and underserved populations/regions.


Assuntos
Insulina/química , Estruturas Metalorgânicas/química , Animais , Glicemia/análise , Sobrevivência Celular/efeitos dos fármacos , Dicroísmo Circular , Diabetes Mellitus Experimental/induzido quimicamente , Diabetes Mellitus Experimental/tratamento farmacológico , Composição de Medicamentos , Estabilidade de Medicamentos , Insulina/metabolismo , Insulina/uso terapêutico , Fígado/patologia , Estruturas Metalorgânicas/toxicidade , Camundongos , Temperatura
12.
IEEE Trans Biomed Circuits Syst ; 12(3): 452-460, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29877810

RESUMO

This paper addresses two key challenges toward an integrated forward error-correcting biosensor based on our previously reported self-assembled quick-response (QR) code. The first challenge involves the choice of the paper substrate for printing and self-assembling the QR code. We have compared four different substrates that includes regular printing paper, Whatman filter paper, nitrocellulose membrane and lab synthesized bacterial cellulose. We report that out of the four substrates bacterial cellulose outperforms the others in terms of probe (gold nanorods) and ink retention capability. The second challenge involves remote activation of the analyte sampling and the QR code self-assembly process. In this paper, we use light as a trigger signal and a graphite layer as a light-absorbing material. The resulting change in temperature due to infrared absorption leads to a temperature gradient that then exerts a diffusive force driving the analyte toward the regions of self-assembly. The working principle has been verified in this paper using assembled biosensor prototypes where we demonstrate higher sample flow rate due to light induced thermal gradients.


Assuntos
Bactérias/química , Técnicas Biossensoriais/métodos , Celulose/química , Ouro/química , Nanotubos/química , Papel , Técnicas Biossensoriais/instrumentação
13.
ACS Sens ; 3(5): 1024-1031, 2018 05 25.
Artigo em Inglês | MEDLINE | ID: mdl-29741092

RESUMO

Sensors for human health and performance monitoring require biological recognition elements (BREs) at device interfaces for the detection of key molecular biomarkers that are measurable biological state indicators. BREs, including peptides, antibodies, and nucleic acids, bind to biomarkers in the vicinity of the sensor surface to create a signal proportional to the biomarker concentration. The discovery of BREs with the required sensitivity and selectivity to bind biomarkers at low concentrations remains a fundamental challenge. In this study, we describe an in-silico approach to evolve higher sensitivity peptide-based BREs for the detection of cardiac event marker protein troponin I (cTnI) from a previously identified BRE as the parental affinity peptide. The P2 affinity peptide, evolved using our in-silico method, was found to have ∼16-fold higher affinity compared to the parent BRE and ∼10 fM (0.23 pg/mL) limit of detection. The approach described here can be applied towards designing BREs for other biomarkers for human health monitoring.


Assuntos
Técnicas Biossensoriais/métodos , Peptídeos/química , Sequência de Aminoácidos , Biomarcadores/análise , Dicroísmo Circular , Simulação por Computador , Espectroscopia Dielétrica , Humanos , Imunoensaio , Limite de Detecção , Microscopia Eletrônica de Varredura , Reprodutibilidade dos Testes , Ressonância de Plasmônio de Superfície , Troponina I/química
14.
Anal Chem ; 90(13): 7880-7887, 2018 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-29790737

RESUMO

Plasmonic biosensors based on the refractive index sensitivity of localized surface plasmon resonance (LSPR) are considered to be highly promising for on-chip and point-of-care biodiagnostics. However, most of the current plasmonic biosensors employ natural antibodies as biorecognition elements, which can easily lose their biorecognition ability upon exposure to environmental stressors (e.g., temperature and humidity). Plasmonic biosensors relying on molecular imprints as recognition elements (artificial antibodies) are hypothesized to be an attractive alternative for applications in resource-limited settings due to their excellent thermal, chemical, and environmental stability. In this work, we provide a comprehensive comparison of the stability of plasmonic biosensors based on natural and artificial antibodies. Although the natural antibody-based plasmonic biosensors exhibit superior sensitivity, their stability (temporal, thermal, and chemical) was found to be vastly inferior to those based on artificial antibodies. Our results convincingly demonstrate that these novel classes of artificial antibody-based plasmonic biosensors are highly attractive for point-of-care and resource-limited conditions where tight control over transport, storage, and handling conditions is not possible.


Assuntos
Anticorpos/química , Materiais Biomiméticos/química , Ressonância de Plasmônio de Superfície/métodos , Adsorção , Ouro/química , Impressão Molecular , Polímeros/química , Estabilidade Proteica
15.
Langmuir ; 34(13): 4036-4042, 2018 04 03.
Artigo em Inglês | MEDLINE | ID: mdl-29528233

RESUMO

Surface functionalization of nanodiamonds (NDs), which is of great interest in advanced material and therapeutic applications, requires the immobilization of functional species, such as nucleic acids, bioprobes, drugs, and metal nanoparticles, onto NDs' surfaces to form stable nanoconjugates. However, it is still challenging to modify the surface of NDs due to the complexity of their surface chemistry and the low density of each functional group on the surfaces of NDs. In this work, we demonstrate a general applicable surface functionalization approach for the preparation of ND-based core-shell nanoconjugates using dopamine polymerization. By taking advantage of the universal adhesion and versatile reactivity of polydopamine, we have effectively conjugated DNA and silver nanoparticles onto NDs. Moreover, the catalytic activity of ND-supported silver nanoparticle was characterized by the reduction of 4-nitrophenol, and the addressability of NDs was tested through DNA hybridization that formed satellite ND-gold nanorod conjugation. This simple and robust method we have presented may significantly improve the capability for attaching various functionalities onto NDs and open up new platforms for applications of NDs.

16.
Small ; 14(15): e1704006, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29516638

RESUMO

Large quantities of highly toxic organic dyes in industrial wastewater is a persistent challenge in wastewater treatment processes. Here, for highly efficient wastewater treatment, a novel membrane based on bacterial nanocellulose (BNC) loaded with graphene oxide (GO) and palladium (Pd) nanoparticles is demonstrated. This Pd/GO/BNC membrane is realized through the in situ incorporation of GO flakes into BNC matrix during its growth followed by the in situ formation of palladium nanoparticles. The Pd/GO/BNC membrane exhibits highly efficient methylene orange (MO) degradation during filtration (up to 99.3% over a wide range of MO concentrations, pH, and multiple cycles of reuse). Multiple contaminants (a cocktail of 4-nitrophenol, methylene blue, and rhodamine 6G) can also be effectively treated by Pd/GO/BNC membrane simultaneously during filtration. Furthermore, the Pd/GO/BNC membrane demonstrates stable flux (33.1 L m-2 h-1 ) under 58 psi over long duration. The novel and robust membrane demonstrated here is highly scalable and holds a great promise for wastewater treatment.


Assuntos
Celulose/química , Nanopartículas Metálicas/química , Ultrafiltração/métodos , Purificação da Água/métodos , Bactérias/isolamento & purificação , Catálise , Grafite/química , Paládio/química
17.
Small ; 14(7)2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29323458

RESUMO

Interfacing biomolecules with functional materials is a key strategy toward achieving externally-triggered biological function. The rational integration of functional proteins, such as enzymes, with plasmonic nanostructures that exhibit unique optical properties such as photothermal effect provides a means to externally control the enzyme activity. However, due to the labile nature of enzymes, the photothermal effect of plasmonic nanostructures is mostly utilized for the enhancement of the biocatalytic activity of thermophilic enzymes. In order to extend and utilize the photothermal effect to a broader class of enzymes, a means to stabilize the immobilized active protein is essential. Inspired by biomineralization for the encapsulation of soft tissue within protective exteriors in nature, metal-organic framework is utilized to stabilize the enzyme. This strategy provides an effective route to enhance and externally modulate the biocatalytic activity of enzymes bound to functional nanostructures over a broad range of operating environments that are otherwise hostile to the biomolecules.


Assuntos
Ensaios Enzimáticos/métodos , Nanopartículas Metálicas/química , Catálise , Nanoestruturas/química , Ressonância de Plasmônio de Superfície
18.
Nano Lett ; 18(2): 987-993, 2018 02 14.
Artigo em Inglês | MEDLINE | ID: mdl-29314859

RESUMO

Biological materials have the ability to withstand extreme mechanical forces due to their unique multilevel hierarchical structure. Here, we fabricated a nacre-mimetic nanocomposite comprised of silk fibroin and graphene oxide that exhibits hybridized dynamic responses arising from alternating high-contrast mechanical properties of the components at the nanoscale. Dynamic mechanical behavior of these nanocomposites is assessed through a microscale ballistic characterization using a 7.6 µm diameter silica sphere moving at a speed of approximately 400 m/s. The volume fraction of graphene oxide in these composites is systematically varied from 0 to 32 vol % to quantify the dynamic effects correlating with the structural morphologies of the graphene oxide flakes. Specific penetration energy of the films rapidly increases as the distribution of graphene oxide flakes evolves from noninteracting, isolated sheets to a partially overlapping continuous sheet. The specific penetration energy of the nanocomposite at the highest graphene oxide content tested here is found to be significantly higher than that of Kevlar fabrics and close to that of pure multilayer graphene. This study evidently demonstrates that the morphologies of nanoscale constituents and their interactions are critical to realize scalable high-performance nanocomposites using typical nanomaterial constituents having finite dimensions.

19.
ACS Sens ; 3(2): 342-351, 2018 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-29336151

RESUMO

Most biosensors relying on antibodies as recognition elements fail in harsh environment conditions such as elevated temperatures, organic solvents, or proteases because of antibody denaturation, and require strict storage conditions with defined shelf life, thus limiting their applications in point-of-care and resource-limited settings. Here, a metal-organic framework (MOF) encapsulation is utilized to preserve the biofunctionality of antibodies conjugated to nanotransducers. This study investigates several parameters of MOF coating (including growth time, surface morphology, thickness, and precursor concentrations) that determine the preservation efficacy against different protein denaturing conditions in both dry and wet environments. A plasmonic biosensor based on gold nanorods as the nanotransducers is employed as a model biodiagnostic platform. The preservation efficacy attained through MOF encapsulation is compared to two other commonly employed materials (sucrose and silk fibroin). The results show that MOF coating outperforms sucrose and silk fibroin coatings under several harsh conditions including high temperature (80 °C), dimethylformamide, and protease solution, owing to complete encapsulation, stability in wet environment and ease of removal at point-of-use by the MOF. We believe this study will broaden the applicability of this universal approach for preserving different types of on-chip biodiagnostic reagents and biosensors/bioassays, thus extending the benefits of advanced diagnostic technologies in resource-limited settings.


Assuntos
Técnicas Biossensoriais/métodos , Ouro/química , Estruturas Metalorgânicas/química , Nanotubos/química , Sistemas Automatizados de Assistência Junto ao Leito , Anticorpos Imobilizados/química , Técnicas Biossensoriais/instrumentação , Fibroínas/química
20.
Light Sci Appl ; 7: 29, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30839611

RESUMO

Fluorescence-based techniques are the cornerstone of modern biomedical optics, with applications ranging from bioimaging at various scales (organelle to organism) to detection and quantification of a wide variety of biological species of interest. However, the weakness of the fluorescence signal remains a persistent challenge in meeting the ever-increasing demand to image, detect, and quantify biological species with low abundance. Here, we report a simple and universal method based on a flexible and conformal elastomeric film with adsorbed plasmonic nanostructures, which we term a "plasmonic patch," that provides large (up to 100-fold) and uniform fluorescence enhancement on a variety of surfaces through simple transfer of the plasmonic patch to the surface. We demonstrate the applications of the plasmonic patch in improving the sensitivity and limit of detection (by more than 100 times) of fluorescence-based immunoassays implemented in microtiter plates and in microarray format. The novel fluorescence enhancement approach presented here represents a disease, biomarker, and application agnostic ubiquitously applicable fundamental and enabling technology to immediately improve the sensitivity of existing analytical methodologies in an easy-to-handle and cost-effective manner, without changing the original procedures of the existing techniques.

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