MOLOKO optical biosensor will present maximized characteristics in detection by the exploitation of inherent features of the organic optoelectronic, plasmonic and immunoassay components comprising the overall system.

This ambition will be supported by implementing a synergetic approach in integrating 4 technology-enabling building blocks which allows for the realization of high-added value biosensor:
–  An organic light source as organic light-emitting transistor (OLET) enables an optics-less lightcoupling in a high-sensitive detection scheme
– A non-conventional nanostructured plasmonic surfaces which allow to detect refractive index modulation at the grating surface opposite to where the probing excitation light is impinging
– An organic photodetector (OPD) that is monolithically integrated in the OLET structure by multistack side-by-side fabrication in order to enhance sensor miniaturization
– Recombinant antibody technology to be used to improve the sensitivity of detection by utilizing oriented and site-specific immobilization of antibodies and to increase the specificity of the assay and reduce the inhibiting matrix effects with respect to the conventional competitive assay format.

Below, we report a sketch of the sensor functioning. The key photonic component at the basis of the architecture of MOLOKO biosensor is the OLET that enables the control of the spatial position of the light emission zone within the micrometer-long transistor channel by acting on the gate voltage7. We fully exploit all the photonic features intrinsic to OLETs by monolithically integrating organic multistack OPDs onto the charge-injecting electrodes in OLET. The OPDs are deposited as stripes on top of the electrode surface of OLET by mechanical micrometric alignment: the OPDs work as integrated detectors in the organic photonic module.

Finally, the module is assembled with the functionalized plasmonic grating (optoplasmonic module) that reflects back the impinging OLET electroluminescence, once modulated in peak emission wavelength and spectrum broadness, into the OPD for signal detection. Thus, the optical detection scheme is oversimplified given that light-emitting and sensing components are highly integrated (no bulky detectors allowed) and no optical components are used for coupling modulated light.

MOLOKO project will bring an optoplasmonic module into the harsh industrial environment of a milking system. The overall system is comprised of MOLOKO photonic sensor, an electronic board, the MOLOKO cradle used to recharge the embedded battery, the user’s mobile device and the back-end web service.
The electronic board is connected by one side to the interface with the sensors and the actuators (drivers), and by the other side to the interface with the back-end (user’s mobile device)
The embedded software runs into a low power microcontroller that manages the data sensor acquisition, the actuators controls, the power management, the data recording and data streaming, etc.

For safety reasons, contactless energy transfer will be used to recharge the MOLOKO portable device battery. Such technology will allow providing the device with a high ingress protection making it washable which is essential for the in-field validation of photonic sensor. A housing will be designed and developed in rapid prototyping taking into account the user requirements, the insertion of the disposable part and the environmental constraints.

The innovative line of MOLOKO technology will greatly extend the in-house tools available for the rapid and low-cost acceptance screening of milk from primary producers (farmers). Once integrated in the milking machine, MOLOKO sensor can detect the non-compliant units during self-checking with consequent avoidance of mixing milk from different cows in the same tank. Moreover, official control, based on risk analysis “from farm to fork”, will be increasingly integrated by bottom-up innovative systems for self-monitoring by food business operators at each segment of the milk chain. Indeed, the MOLOKO photonic sensor can also be used as handheld detection system for improving self-monitoring capability of food business operators based on modernized risk management framework (HACCP plans and daily traceability).
In this scenario, the target analyses are properly chosen in order to meet the needs of the several food operators at the different checkpoints of the milk chain a single analytical instrument:

• Mycotoxins from animal feed
• Antibacterial drugs
• Staphylococcus eneterotoxin
• Quality parameters

From process and logistics flow perspective, it is of outmost importance to diagnose the level of contaminants at the earliest in the supply chain.  As a preventative approach, the farmers are the ones that can enable the earliest detection of those contaminants in the value chain, and consequently the prevention of contamination in the bulk milk by implementing the appropriate corrective measures.