In the last decades, the plasmonic effect of metallic nanoparticles (NPs) has been broadly exploited for label-free optical sensing. To analyze the scattered light from NPs, dark-field microscopy is the most employed technique, which typically requires complex and expensive set-ups. To overcome these limitations, here, we propose a new methodology to develop plasmonic sensors. In our approach, gold nanoparticles (AuNPs) are bonded to the end-face of convectional multimode optical fibers (MMFs). The measuring set-up is as follows: light is launched from a white light source to the end of the MMF where AuNPs are located. The guided light interacts with the AuNPs where localized surface plasmons are excited. The absorption and reflection spectra are analyzed with a miniature spectrometer. Our system is robust, portable, cost effective, and operates in the 250-1200 nm wavelength range. Moreover, the acquisition of data is in real time. Instead of monitoring the conventional shift in the plasmon resonance, our strategy relies on the plasmon resonance energy transfer (PRET) from functionalized AuNPs to metal ion complexes build on top of the AuNPs surface. Our methodology facilitates the detection of copper ions (Cu2+) in water (<10^(-9) M) by the formation of conjugated resonant complexes of N-[3-(trimethoxysilyl)propyl]ethylenediamine (TMSen). By applying our technology, new emerging, fast, and cheaper devices with intrinsic high sensitivity can be developed for the detection of different heavy metal ions in water, which are harmful to the environment and human health.
Over the past decade conducting polymer electrodes have played an important role in bio-sensing and actuation.
Recent developments in the field of organic electronics have made available a variety of devices that bring unique
capabilities at the interface with biology. One example is organic electrochemical transistors (OECTs) that are being
developed for a variety of bio-sensing applications, including the detection of ions, and metabolites, such as glucose and
Room temperature ionic liquids (RTILs) are organic salts, which are liquid at ambient temperature. Their nonvolatile
character and thermal stability makes them an attractive alternative to conventional organic solvents. Here we
report an enzymatic sensor based on an organic electro-chemical transistor with RTIL's as an integral part of its structure
and as an immobilization medium for the enzyme and the mediator. Further investigation shows that these platforms can
be incorporated into flexible materials such as carbon cloth and can be utilized for bio-sensing. The aim is to incorporate
the overall platform in a wearable sensor to improve athlete performance with regards to training. In this manuscript an
introduction to ionic liquids (ILs), IL - enzyme mixtures and a combination of these novel materials being used on
OECTs are presented.
Nowadays, wearable sensors such as heart rate monitors and pedometers are in common use. The use of
wearable systems such as these for personalized exercise regimes for health and rehabilitation is particularly interesting.
In particular, the true potential of wearable chemical sensors, which for the real-time ambulatory monitoring of bodily
fluids such as tears, sweat, urine and blood has not been realized. Here we present a brief introduction into the fields of
ionogels and organic electrochemical transistors, and in particular, the concept of an OECT transistor incorporated into a
sticking-plaster, along with a printable "ionogel" to provide a wearable biosensor platform.
In microfluidics, valves and pumps that can combine specifications like precise flow control, provision of precise reagent
quantities, minimal sample carryover, and low-cost manufacture, while also being inherently compatible with
microfluidic system fabrication, are beyond the current state of the art. Actuators in micro-fluidics made using stimuliresponsive
materials are therefore of great interest as functional materials since actuation can be controlled without
physical contact, offering improvements in versatility during manifold fabrication, and control of the actuation
Herein we review the potential use of novel approaches to valving and pumping based on stimuli-responsive polymers
for controlling fluid movement within micro-fluidic channels. This has the potential to dramatically simplify the design,
fabrication and cost of microfluidic systems. In particular, stimuli-responsive gels incorporating ionic liquids (ILs)
produce so-called 'ionogels' that have many advantages over conventional materials. For example, through the tailoring
of chemical and physical properties of ILs, robustness, acid/ base character, viscosity and other critical operational
characteristics can be finely adjusted. Therefore, the characteristics of the ionogels can be tuned by simply changing the
IL and so the actuation behaviour of micro-valves made from these novel materials can be more closely controlled.