Analysis of water-soluble vitamins in biopharma raw materials by electrophoresis micro-chips with contactless conductivity detection

Detailed information concerning the composition of the raw materials employed in the production of biologics is important for the efficient control and optimization of bioprocesses. The analytical methods used in these applications must be simple and fast as well as be easily transferable from one site to another. In that context, microchip‐based electrophoresis represents a promising tool for application in the analysis of raw materials in biologics. Using electrophoresis micro‐chips, analysis times can be reduced to seconds and high separation efficiencies can be achieved using extremely low volume samples, minimal reagent consumption and waste generation, low cost/disposability, portability and ease of mass‐production [1]. Additionally the use of Capacitively Coupled Contactless Conductivity Detection (C4D) offers a rather simple and yet sensitive method for detection of ionic species. Recently, C4D has gained much popularity as on‐chip detection in electrophoresis micro‐chips [2]. The main reason for this is that there is no physical contact of the detection electrodes with the electrolyte solution. Therefore, the integration of this detection mode within the analytical system is rather simple. Furthermore, the background noise is significantly reduced leading to lower detection limits than the conventional contact conductivity detection. Vitamins are present at very low concentrations in biopharma raw materials and are usually determined using HPLC and CE methods [3]. Electrophoresis micro‐chips are a very good alternative to these techniques due to the shorter analysis time and yet very good resolution, among others. In this paper, we present the application of electrophoresis micro‐chips with C4D detection to the analysis of water‐soluble vitamins in raw materials used for the production of biologics in bioreactors. For that purpose, hybrid PDMS/glass chips were fabricated by using standard photolithographic techniques (Figure 1). The chip structure contains an extremely long channel of 101 mm (50 x 50 μm width x depth). Figure 2 shows the setup used for vitamins detection

La subjetividad como factor determinante en el sentido de una sentencia penal

El objetivo es analizar la forma en que una sentencia es emitida por los agentes intrínsecos del resolutor, lo que determina de manera definitiva el sentido de la misma. Aunque resulta innegable que existen mecanismos objetivos en la determinación de la sentencia, es imperante revisar cómo algunos elementos subjetivos inherentes al resolutor pueden contribuir también a dicha resolución. En este sentido, con base en antecedentes investigativos nacionales e internacionales, la obra postula que factores como la edad, el género, estados de ánimo y experiencias personales, entre otros, tornan la decisión judicial parcialmente subjetiva

Analysis of biopharma raw materials by electrophoresis microchips with contactless conductivity detection

Detailed information concerning the composition of the raw materials employed in the production of biologics is important for the efficient control and optimization of bioprocesses. We demonstrate the application of electrophoresis microchips with capacitively-coupled contactless conductivity detection (C4D) to the analysis of wa-ter-soluble vitamins and metal cations in raw material solutions that are subse-quently fed into bioreactors for the production of biologics

Liquid recirculation in microfluidic channels by the interplay of capillary and centrifugal forces

We demonstrate a technique to recirculate liquids in a microfluidic device, maintaining a thin fluid layer such that typical diffusion times for analytes to reach the device surface are < 1 min. Fluids can be recirculated at least 1000 times across the same surface region, with no change other than slight evaporation, by alternating the predominance of centrifugal and capillary forces. Mounted on a rotational platform, the device consists of two hydrophilic layers separated by a thin pressure-sensitive adhesive (PSA) layer that defines the microfluidic structure. We demonstrate rapid, effective fluid mixing with this device

Monolithic centrifugal microfluidic platform for bacteria capture and concentration, lysis, nucleic-acid amplification, and real-time detection

We report the design, fabrication, and characterization of a polymer centrifugal microfluidic system for the specific detection of bacterial pathogens. This single-cartridge platform integrates bacteria capture and concentration, supernatant solution removal, lysis, and nucleic-acid sequence-based amplification (NASBA) in a single unit. The unit is fabricated using multilayer lamination and consists of five different polymer layers. Bacteria capture and concentration are accomplished by sedimentation in five minutes. Centrifugation forces also drive the subsequent steps. A wax valve is integrated in the cartridge to enable high-speed centrifugation. Oil is used to prevent evaporation during reactions requiring thermal cycling. Device functionality was demonstrated by real-time detection of E. coli from a 200-muL sample

Impactos del turismo residencial percibidos por la población local: Una aproximación cualitativa desde la teoría del intercambio social

Artículo de investigaciónDesde la teoría del intercambio social, se analizan los impactos del turismo residencial en Puerto Morelos, Quintana Roo, México. Con base en entrevistas a residentes permanentes en el destino, se evidencia que el turismo residencial es asociado al empleo, al efecto multiplicador, la difusión de la cultura, el cuidado del entorno natural y acciones altruistas con locales. El incremento del precio de los inmuebles y la competencia empresarial son considerados costos del fenómeno. Se concluye que los pobladores realizan una valoración de costos y beneficios tanto a nivel individual como colectivo para definir su posición frente al turismo residencial