Method for producing an array of planar microparticles with surface molecular multiplexing, resulting array and use thereof

A method for producing a plurality of individual chemically functionalized microparticles, the method comprising:

• (a) preparing a layered structure including, in order from top to bottom:
• (i) a structuration layer having a top structuration layer surface and a bottom structuration layer surface, and
• (ii) a multi-layer substrate comprising:
• an upper substrate layer having an upward facing first substrate surface, that is attached to the bottom structuration layer surface of the structuration layer, and a downward facing second substrate surface below the first substrate surface;
• and
• a lower substrate layer having an upward facing third substrate surface, attached to the second substrate surface of the upper substrate layer, and a downward facing fourth substrate surface below the third substrate surface, wherein:
• the upper substrate layer comprises an upper substrate material, and the lower substrate layer comprises a lower substrate material;
• the structuration layer comprises a structuration material selected from the group consisting of polycrystalline silicon, silicon oxide, silicon nitride, gold, platinum, aluminum, copper, nickel, cobalt, chromium, metal oxides, tantalum silicate, iron silicate, aluminum silicates, tantalum silicide, iron silicide and aluminum silicide;
• the upper substrate material and the structuration material are different materials;
• and
• the upper substrate material and the lower substrate material are different materials;
• (b) shaping the top structuration layer surface of the structuration layer using a first microelectronic lithography technique to obtain a shaped structuration layer having an uncovered area, and engraving the uncovered area of the shaped structuration layer to obtain a plurality of engraved structuration layers each having a defined thickness, wherein:
• each of the plurality of engraved structuration layers is attached to the first substrate surface of the upper substrate layer via an engraved bottom structuration layer surface,
• each of the plurality of engraved structuration layers has an engraved top structuration layer surface, and
• the engraving of the shaped structuration layer creates an uncovered area of the upper substrate layer;
• (c) engraving the uncovered area of the upper substrate layer using a second microelectronic technique to form more than one foot comprising the upper substrate material, wherein:
• each foot has a width that varies through the height of the foot, such that the width decreases from the engraved bottom structuration layer surface to a midpoint of the height, and the width increases from the midpoint to the third substrate surface;
• each foot is attached to the engraved bottom structuration layer surface of one or the engraved structuration layers, such that each of the plurality of the engraved structuration layers is attached to a single foot;
• each foot is formed by engraving the uncovered area of the first substrate surface to the third substrate surface of the lower substrate layer;
• and
• each foot comprises a planar cross-section that is smaller than a planar cross-section of an engraved structuration layer to which it is attached;
• (d) chemically functionalizing the engraved top structuration layer surface an upper face of each of the plurality of engraved structuration layers with one or more molecular components to obtain, on each of the plurality of engraved structuration layers, a monolayer comprising the one or more molecular components attached to the engraved top structuration layer surface, wherein each of the plurality of engraved structuration layers is chemically functionalized using a molecule printing technique selected from the group consisting of a microcontact printing, a dip-pen nanolithography and a polymer-pen lithography;
• and
• (e) breaking each foot by applying a controlled mechanical breaking load to each foot, thereby forming the plurality of chemically functionalized microparticles, wherein a rupture limit of the structuration material (LSTM) is greater than a rupture limit of the upper substrate material (LUTM) according to the formula:
• (LSTM)/LUSM)>1;
• and
• wherein each chemically functionalized microparticle comprises:
• a residual portion of the foot comprising the upper substrate material, wherein the residual portion comprises a planar cross-section that is smaller than the planar cross-section of the engraved structuration layer to which it is attached, and wherein the residual portion of each foot has a width that decreases in a direction from the engraved bottom structuration layer surface to a terminus of the residual portion;
• the engraved structuration layer defining both geometry and lateral dimensions of a top surface of the chemically functionalized microparticle;
• and
• the monolayer comprising the one or more molecular components attached to the engraved top structuration layer surface of the engraved structuration layer.