RESUMO
Microfluidic paper-based analytical devices (µPADs) are emerging as powerful analytical platforms in clinical diagnostics, food safety, and environmental protection because of their low cost and favorable substrate properties for biosensing. However, the existing top-down fabrication methods of paper-based chips suffer from low resolution (>200 µm). Additionally, papers have limitations in their physical properties (e.g., thickness, transmittance, and mechanical flexibility). Here, we demonstrate a bottom-up approach for the rapid fabrication of heterogeneously controlled paper-based chip arrays. We simply print a wax-patterned microchip with wettability contrasts, enabling automatic and selective assembly of cellulose microfibers to construct predefined paper-based microchip arrays with controllable thickness. This paper-based microchip printing technology is feasible for various substrate materials ranging from inorganic glass to organic polymers, providing a versatile platform for the full range of applications including transparent devices and flexible health monitoring. Our bottom-up printing technology using cellulose microfibers as the starting material provides a lateral resolution down to 42 ± 3 µm and achieves the narrowest channel barrier down to 33 ± 2 µm. As a proof-of-concept demonstration, a flexible paper-based glucose monitor is built for human health care, requiring only 0.3 µL of sample for testing.
Assuntos
Celulose , Técnicas Analíticas Microfluídicas , Celulose/química , Glucose , Humanos , Dispositivos Lab-On-A-Chip , Microfluídica , Papel , MolhabilidadeRESUMO
Intercellular Ca(2+) waves are propagation of Ca(2+) transients among cells that could be initiated by chemical stimulation. Current methods for analyzing intercellular Ca(2+) waves are difficult to realize localized chemical stimulations upon the target cell without interfering with adjacent contacting cells. In this paper, a simple and flexible microfluidic method was developed for investigating the intercellular communication of Ca(2+) signals. A cross-patterned microfluidic chip was designed and fabricated with polydimethylsiloxane as the structural material. Localized chemical stimulation was achieved by a new strategy based on hydrodynamic gating technique. Clusters of target cells were seeded at the location within 300 µm downstream of the intersection of the cross-shaped microchannel. Confined lateral molecular diffusion largely minimized the interference from diffusion-induced stimulation of adjacent cells. Localized stimulation of the target cell with adenosine 5'-triphosphate successfully induced the propagation of intercellular Ca(2+) waves among a population of adjacent contacting cells. Further inhibition studies verified that the propagation of calcium signals among NIH-3 T3 cells was dependent on direct cytosolic transfer via gap junctions. The developed microfluidic method provides a versatile platform for investigating the dynamics of intercellular communications.
Assuntos
Cálcio/química , Técnicas Analíticas Microfluídicas/métodos , Trifosfato de Adenosina/química , Animais , Soluções Tampão , Cálcio/metabolismo , Sinalização do Cálcio , Comunicação Celular , Simulação por Computador , Citosol/metabolismo , Dimetilpolisiloxanos/química , Desenho de Equipamento , Junções Comunicantes/metabolismo , Hidrodinâmica , Camundongos , Microfluídica , Modelos Químicos , Modelos Teóricos , Células NIH 3T3 , Óptica e Fotônica , Transdução de Sinais , Estresse Mecânico , Fatores de TempoRESUMO
Exosomes, endogenous nanosized particles (50-150 nm) secreted and absorbed by cells, have been recently used as diagnostic and therapeutic platforms in cancer treatment. The integration of exosome-based delivery with multiple therapeutic modalities could result in better clinical outcomes and reduced-sided effects. Here, we combined the targeting and biocompatibility of designer exosomes with chemo/gene/photothermal therapy. Our platform consists of exosomes loaded with internalized doxorubicin (DOX, a model cancer drug) and coated with magnetic nanoparticles conjugated with molecular beacons capable of targeting miR-21 for responsive molecular imaging. The coated magnetic nanoparticle enables enrichment of the exosomes at the tumor site by external magnetic field guidance. After the exosomes are gathered at the tumor site, the application of near-infrared radiation (NIR) induces localized hyperthermia and triggers the release of cargoes loaded inside the exosome. The released molecular beacon can target the miR-21 for both imaging and gene silencing. Meanwhile, the released doxorubicin serves to kill the cancer cells. About 91.04 % of cancer cells are killed after treatment with Exo-DOX-Fe3O4@PDA-MB under NIR. The ability of the exosome-based method for cancer therapy has been demonstrated by animal models, in which the tumor size is reduced dramatically by 97.57 % with a magnetic field-guided tumor-targeted chemo/gene/photothermal approach. Thus, we expected this designer exosome-mediated multi-mode therapy to be a promising platform for the next-generation precision cancer nanomedicines.
Assuntos
Exossomos , Hipertermia Induzida , Nanopartículas , Neoplasias , Animais , Linhagem Celular Tumoral , Doxorrubicina , Neoplasias/terapia , Fototerapia , Terapia Fototérmica , PolímerosRESUMO
"Click" chemistry-based surface modification strategy was developed for PDMS microchips to enhance separation performance for both amino acids and proteins. Alkyne-PEG was synthesized by a conventional procedure and then "click" grafted to azido-PDMS. FTIR absorption by attenuated total reflection and contact angle measurements proved efficient grafting of alkyne-PEG onto PDMS surface. Manifest EOF regulation and stability of PEG-functionalized PDMS microchips were illustrated via EOF measurements and protein adsorption investigations. The stability of nonspecific protein adsorption resistance property was investigated up to 30 days. Separation of fluorescence-labeled amino acids and proteins was further demonstrated with high repeatability and reproducibility. Comparison of protein separation using PDMS microchips before and after surface modification suggested greatly improved electrophoretic performance of the PEG-functionalized PDMS microchips. We expect the "click" chemistry-based surface modification method to have wide applications in microseparation of proteins with long-term surface stability.
Assuntos
Química Click/instrumentação , Química Click/métodos , Dimetilpolisiloxanos/química , Eletroforese em Microchip/instrumentação , Eletroforese em Microchip/métodos , Proteínas/isolamento & purificação , Adsorção , Aminoácidos/isolamento & purificação , Eletro-Osmose , Fluoresceína-5-Isotiocianato , Concentração de Íons de Hidrogênio , Polietilenoglicóis , Reprodutibilidade dos Testes , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de SuperfícieRESUMO
BACKGROUND: In clinical practice, checkrein deformity is usually found in patients with calf injuries after ankle fracture or distal tibial fracture. The patients with checkrein deformity mainly report distending pain in toe tips, pain when walking or wearing shoes, and gait instability. Previous studies have mainly reported surgical treatments for checkrein deformity, while few studies have reported using comprehensive rehabilitation alone to improve the checkrein deformity. CASE SUMMARY: A 28-year-old woman was admitted to the hospital due to unstable gait caused by pain in the right hallux, for which she was unable to stretch for over three months. The patient had undergone "resection of ameloblastoma at the right mandible, mandibulectomy, and autogenous right fibula grafting". The patient's hallux toe, as well as the second and third toes of the right foot could not be stretched, with pain in all the toes during walking. Based on the medical records of the patient, as well as the results of physical and auxiliary examinations, the main diagnosis was checkrein deformity in the right foot. Since the patient refused surgical treatment, rehabilitation was the only treatment option. At discharge, the patient reported evident improvement in the pain in the toes, gait stability, as well as increased ability to climb up and downstairs. CONCLUSION: Comprehensive rehabilitation therapy could effectively alleviate the manifestations of checkrein deformity and improve the walking ability of the patients.
RESUMO
A PEG-NH2-based environmentally friendly surface modification strategy was developed for PDMS microchips to prevent protein adsorption and to enhance separation performance. PEG-NH2 was synthesized using a modified synthesis procedure. A two-step grafting method was used for PDMS modification. FTIR absorption by attenuated total reflection and contact angle measurements verified the successful grafting of PEG-NH2 onto the PDMS surface. Subsequent EOF Measurements and protein adsorption studies of PEG-modified PDMS microchips revealed noticeable EOF suppression and resistance to nonspecific protein adsorption for more than 30 days. Separation of four FITC-labeled amino acids was further demonstrated with high repeatability and reproducibility. Comparison of electrophoresis of 3-(2-furoyl)quinoline-2-carboxaldehyde-labeled BSA using PDMS microchips before and after surface modification resulted in significantly improved electrophoretic performance of the PEG-modified PDMS microchips, suggesting that our PEG grafting method successfully modified PDMS surface property and prevented adsorption of proteins. We expect that this environmentally friendly surface modification method will be useful for future protein separations with long-term surface stability.
Assuntos
Dimetilpolisiloxanos/química , Eletroforese em Microchip/métodos , Química Verde/métodos , Nylons/química , Polietilenoglicóis/química , Adsorção , Aminoácidos/isolamento & purificação , Eletro-Osmose , Fluoresceína-5-Isotiocianato/química , Concentração de Íons de Hidrogênio , Proteínas/isolamento & purificação , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Fatores de TempoRESUMO
To investigate rapid suspension cell signaling, a microfluidic platform was urgently needed for flexibly manipulation of single cells and simultaneous generation of controllable chemical signals to stimulate single cells. In this paper, a microfluidic biosensor was developed to monitor intracellular calcium signal, integrated with single-cell trapping, chemical stimulation and releasing. Selective entrapment and discharge of individual cell were achieved by controlling the deformable membrane with pneumatic traps. The activation of intracellular calcium signal was qualitatively and quantitatively investigated by high-controllable chemical single-cell stimulation based on flexible hydrodynamic gating. And performing chemical stimulation and control assay in the same channel would improve the experimental robustness and effectiveness. Further investigation of the cellular responses to ATP pulses of varying concentrations and durations indicated that 20⯵M ATP pulses with duration as short as 200â¯ms resulted in the same level of Ca2+ response induced by sustained stimulations. Washing with buffer for 30â¯s was sufficient for single cell to recover from receptor desensitization caused by ATP stimulation. In addition, the responses of cells to ATP stimulation were heterogeneous. The developed microfluidic method opens up a new avenue for intracellular signaling studies and drug screening.
Assuntos
Técnicas Biossensoriais/instrumentação , Cálcio/análise , Dispositivos Lab-On-A-Chip , Técnicas Analíticas Microfluídicas/instrumentação , Trifosfato de Adenosina/metabolismo , Animais , Técnicas Biossensoriais/métodos , Dimetilpolisiloxanos/química , Fluoresceína/química , Fluorescência , Células HeLa , Humanos , Hidrodinâmica , Camundongos , Técnicas Analíticas Microfluídicas/métodos , Microscopia de Fluorescência , Células NIH 3T3RESUMO
Multidrug resistance (MDR) is a major hurdle to the success of cancer chemotherapy. Poloxamers have been shown to reverse MDR by inhibiting the P-glycoprotein (P-gp) pump. The objective of this research is to test the feasibility of docetaxel-loaded PLGA-TPGS/Poloxamer 235 nanoparticles to overcome MDR in docetaxel-resistant human breast cancer cell line. Docetaxel-loaded nanoparticles were prepared by a modified nanoprecipitation method using PLGA-TPGS and PLGA-TPGS/Poloxamer 235 mixture, respectively. The PLGA-TPGS/Poloxamer 235 nanoparticles were of spherical shape and have a rough and porous surface. The docetaxel-loaded PLGA-TPGS/Poloxamer 235 porous nanoparticles which had an average size of around 180nm with a narrow size distribution were stable, showing almost no change in particle size and surface charge during the 3-month storage period. The in vitro drug release profile of both nanoparticle formulations showed a biphasic release pattern. There was an increased level of uptake of PLGA-TPGS/Poloxamer 235 porous nanoparticles (PPNPs) in docetaxel-resistant human breast cancer cell line, MCF-7/TXT, in comparison with PLGA-TPGS nanoparticles (PTNPs). The PLGA-TPGS/Poloxamer 235 porous nanoparticles produced significantly higher level of toxicity than both of PLGA-TPGS nanoparticle formulation and Taxotere® both in vitro and in vivo, indicating docetaxel-loaded PLGA-TPGS/Poloxamer 235 porous nanoparticles have significant potential for the treatment of breast cancer.