We present a rigorous electromagnetic theory of the electromagnetic power emitted by a dipole located in the vicinity of
a multilayer stack. We applied this formalism to a luminescent molecule attached to a CMOS photodiode surface and
report light collection efficiency larger than 80% toward the CMOS silicon substrate. We applied this result to the
development of a low-cost, simple, portable device based on CMOS photodiodes technology for the detection and
quantification of biological targets through light detection, presenting high sensitivity, multiplex ability, and fast data
processing. The key feature of our approach is to perform the analytical test directly on the CMOS sensor surface,
improving dramatically the optical detection of the molecule emitted light into the high refractive index semiconductor
CMOS material. Based on adequate surface chemistry modifications, probe spotting and micro-fluidics, we performed
proof-of-concept bio-assays directed against typical immuno-markers (TNF-α and IFN-γ). We compared the developed
CMOS chip with a commercial micro-plate reader and found similar intrinsic sensitivities in the pg/ml range.
We present a parallel calibration technique especially designed to evaluate the potential well spatial shape of multiple
holographic optical tweezers. The basic principle is to extend the conventional unidirectional drag force method to a
multi-axes one, associated with image processing. We then focus on the characterization of anisotropic distorted optical
potential wells of holographic optical tweezers, where the distortion comes from optical aberrations and/or effects due to
nearby ghost or regular traps. We also address the dependence of the diffraction efficiency with the trap position in a given traps pattern.
The way a cell reacts to a stimulus has a strong local nature based on the internal structure of it. Therefore
models which describe, with a certain degree of precision, cell behaviours in response to a deformation of it as
a whole cannot be extrapolated to the local response process. Under these assumptions the regional approach
in single cell assays is earning more and more interest as it provides a more detailed insight on cells dynamics
processes in terms of their morphology, and hence a more accurate description of the implied molecular entities.
In the last decade, the development of a wide variety of optical trapping techniques has provided us a versatile tool
to explore this locality of cells responses enabling a true "regional approach" and deepening our knowledge in the
field. We here propose an apparatus based on multiple holographic optical tweezers and micro-stereolithography
which allows an interactive control of the spatial-temporal characteristics of a trap pattern and the simultaneous
application of different stimuli. These agents are kept separated from one another and from the cells via several
custom-designed reservoirs fabricated via a micro-stereolithographic technique. It is worth noting that the work
is more intended to propose a methodology or tool for meaningful assays rather than a new technique. As a
consequence most of the efforts are being drawn towards to the simplification of the work flow to allow the device
to actually be exploited and provide valuable data, and no more be a simple lab experiment.
Recent studies have shown that the cell is mechanically differentiated both spatially and temporally, leading to a regional approach in cell behaviour essays. Most experiments are based on spatially-controlled contacts between microbeads and cells. We here propose an apparatus based on holographic optical tweezers to put on a target cell a two- or three-dimensional custom-built pattern of beads, with respect to the target cell shape, with both temporal and spatial dynamic control of each contact. In order to avoid disturbance or contact from the excess beads with the target cell, we keep the beads under isolated condition, by placing them in a confinement chamber made by microstereolithography. Our system exploits a digital display to project binary images on a photocurable resin surface, and induce space-resolved photopolymerisation reactions, constructing three-dimensional micro structures with complex shapes, including reservoirs for the filling, outlets, and confinement chambers. Combination of microfluidics, holographic optical tweezers and one supplementary single manually steerable optical tweezers leads to several experimental procedures allowing the sequential or parallel deposition of beads onto a target, with both a spatial and temporal control.