Polymerase chain reaction on a viral nanoparticle

The field of synthetic biology includes studies that aim to develop new materials and devices from biomolecules. In recent years much work has been carried out using a range of biomolecular chassis including α-helical coiled coils, α-sheet amyloids and even viral particles. In this work we show how hybrid bionanoparticles can be produced from a viral M13 bacteriophage scaffold through conjugation to DNA primers that can template a polymerase chain reaction (PCR). This unprecedented example of a PCR on a virus particle has been studied by flow aligned linear dichroism spectroscopy, which gives information on the structure of the product as well as a new protototype methodology for DNA detection. We propose that this demonstration of PCR on the surface of a bionanoparticle is a useful addition to ways in which hybrid assemblies may be constructed using synthetic biology

Aufbau und Biofunktionalisierung einer LSPR-Molekülsensorikeinheit

Der Gebrauch klassischer Oberflächenplasmonenresonanz-Sensoren ist derzeit aufgrund ihrer massiven und justageaufwendigen Bauweise auf den Laborbetrieb beschränkt. Am Fraunhofer IKTS wird gegenwärtig ein miniaturisiertes Sensorsystem entwickelt, dessen Messeffekt auf lokalisierter Oberflächenplasmonenresonanz basiert. Als zentrales Element steht dabei eine mit Fängermolekülen funktionalisierte nanostrukturierte Goldoberfläche in direktem Kontakt mit einem Photodiodenpaar. Bei einer Wechselwirkung des Analyten mit der biologischen Erkennungsstruktur und gleichzeitiger transmittiver Beleuchtung können die Signaländerungen anhand eines einfachen Photostromvergleiches ausgewertet werden –ganz ohne die Verwendung eines aufwendigen Spektrometers. Die vereinfachte und kompakte Bauweise dieses Sensorsystems soll in Zukunft eine Integration in Anlagen zur Online-Prozessüberwachung und Echtzeitdetektion von Biomolekülen erlauben. In diesem Beitrag wird der aktuelle Arbeitsstand des Sensoraufbaus sowie der Biofunktionalisierung dargestellt

Plasmonic sensor system for on-site monitoring of diclofenac molecules

In previous studies, we applied a commercial surface plasmon resonance (SPR) sensor successfully to detect molecules of diclofenac in solutions simulating contaminated water sources. For such laboratory investigations, SPR sensors are well suited and, hence, they are established in the field of environmental and life sciences. However, they lack robustness which limits their applicability for on-site measurements, e.g. directly at water treatment plants. We therefore extended our study and set up a robust low-cost biosensor system. We used nanoimprint lithography to fabricate nanostructured gold surfaces which act as SPR transducers. For readout of the SPR signal the system is equipped with a novel photocur-rent read-out unit allowing to register changes in the SPR signal resulting from specific binding of anti-diclofenac anti-bodies to the diclofenac-functionalized gold surface. The observed shift in the optical transmittance spectra and changes in the photocurrents also proved that diclofenac molecules were successfully immobilized on the sensor substrate. The measurements also showed specific binding of anti-diclofenac antibody with subsequent regeneration

Hydrogel-based plasmonic sensor substrate for the detection of ethanol

The in-line monitoring of ethanol concentration in liquids is a crucial part of process monitoring in breweries and distilleries. Current methods are based on infrared spectroscopy, which is time-consuming and costly, making these methods unaffordable for small and middle-sized companies. To overcome these problems, we presented a small, compact, and cost-effective sensing method for the ethanol content, based on a nanostructured, plasmonically active sensor substrate. The sensor substrate is coated with an ethanol-sensitive hydrogel, based on polyacrylamide and bisacrylamide, which induces a change in the refractive index of the substrate surface. The swelling and shrinking of such hydrogels offer a means to measure the ethanol content in liquids, which can be determined in a simple transmittance setup. In our study, we demonstrated the capability of the sensor principle for the detection of ethanol content ranging from 0 to 30 vol% ethanol. Furthermore, we determined the response time of the sensor substrate to be 5.2 min, which shows an improvement by a factor of four compared to other hydrogel-based sensing methods. Finally, initial results for the sensor’s lifetime are presented

Fast response hydrogel-based plasmonic sensor substrate for the detection of ethanol

The inline monitoring of ethanol concentrations in liquids is a crucial part of process monitoring in breweries and distilleries. Current methods are based on infrared spectroscopy which are bulky and costly making them non-affordable for small and middle-sized companies. To overcome these problems, we present a small, compact and cost-effective sensing method, based on a nanostructured, plasmonically active sensor substrate. The sensor substrate is coated with a microstructured ethanol-sensitive acrylamide-bisacrylamide hydrogel which induces a change of the hydrogel’s refractive index in conjugation with the hydrogel swelling and shrinking. With such an approach, the ethanol concentration in liquids can be determined in a simple optical transmittance setup. In our study, we demonstrate the capability of the sensor principle for the detection of ethanol concentration ranging from 0 to 30 vol%. Furthermore, we determined the response time of the sensor substrate to be less than 10 seconds, which shows an enormous improvement compared to other hydrogel-based sensing methods. Finally, initial results for real sample measurements are presented

Detection of diclofenac molecules by planar and nanostructured plasmonic sensor substrates

Surface plasmon resonance (SPR) sensors are well-established and widely used in the field of environmental and life sciences. To overcome the limitation of SPR sensors to applications in the laboratory environment initial studies on a low-cost nanostructured sensor substrate fabricated by nanoimprint lithography for the development of a SPR-based on-site biosensor system were conducted. For this purpose, diclofenac molecules were successfully immobilized both on planar and nanostructured gold sensor substrates, which was proved by XPS and SPR measurements. For the latter substrates, a specific binding between an anti-diclofenac antibody and immobilized diclofenac can be observed in form of a localized surface plasmon resonance shift in the optical transmission spectrum. The results show that our low-cost sensor substrate is wellsuited as transducer element for future SPR-based biosensors