Direct whole blood analysis by the antigen-antibody chemically-delayed dissociation from nanosensors arrays

The "Bloodless" Blood Test: Intradermal Prick Nanoelectronics for the Blood Extraction-Free Multiplex Detection of Protein Biomarkers

Protein biomarkers' detection is of utmost importance for preventive medicine and early detection of illnesses. Today, their detection relies entirely on clinical tests consisting of painful, invasive extraction of large volumes of venous blood; time-consuming postextraction sample manipulation procedures; and mostly label-based complex detection approaches. Here, we report on a point-of-care (POC) diagnosis paradigm based on the application of intradermal finger prick-based electronic nanosensors arrays for protein biomarkers' direct detection and quantification down to the sub-pM range, without the need for blood extraction and sample manipulation steps. The nanobioelectronic array performs biomarker sensing by a rapid intradermal prick-based sampling of proteins biomarkers directly from the capillary blood pool accumulating at the site of the microneedle puncture, requiring only 2 min and less than one microliter of a blood sample for a complete analysis. A 1 mm long microneedle element was optimal in allowing for pain-free dermal sampling with a 100% success rate of reaching and rupturing dermis capillaries. Current common micromachining processes and top-down fabrication techniques allow the nanobioelectronic sensor arrays to provide accurate and reliable clinical diagnostic results using multiple sensing elements in each microneedle and all-in-one direct and label-free multiplex biomarkers detection. Preliminary successful clinical studies performed on human volunteers demonstrated the ability of our intradermal, in-skin, blood extraction-free detection platform to accurately detect protein biomarkers as a plausible POC detection for future replacement of today's invasive clinical blood tests. This approach can be readily extended in the future to detect other clinically relevant circulating biomarkers, such as miRNAs, free-DNAs, exosomes, and small metabolites.

Nanoribbon Biosensor in the Detection of miRNAs Associated with Colorectal Cancer

A nanoribbon biosensor (NRBS) was developed to register synthetic DNAs that simulate and are analogous to miRNA-17-3p associated with colorectal cancer. Using this nanoribbon biosensor, the ability to detect miRNA-17-3p in the blood plasma of a patient diagnosed with colorectal cancer has been demonstrated. The sensing element of the NRBS was a nanochip based on a silicon-on-insulator (SOI) nanostructure. The nanochip included an array of 10 nanoribbons and was designed with the implementation of top-down technology. For biospecific recognition of miRNA-17-3p, the nanochip was modified with DNA probes specific for miRNA-17-3p. The performance of the nanochip was preliminarily tested on model DNA oligonucleotides, which are synthetic analogues of miRNA-17-3p, and a detection limit of ~10-17 M was achieved. The results of this work can be used in the development of serological diagnostic systems for early detection of colorectal cancer.

Depletion of Highly Abundant Protein Species from Biosamples by the Use of a Branched Silicon Nanopillar On-Chip Platform

Highly abundant serum proteins tend to mask the low- and ultralow-abundance proteins, making low-abundance species detection extremely challenging. While traditional highly abundant protein depletion techniques are effective, they suffer from nonspecific binding problems and laborious sample manipulation procedures, and the kinetics of release of current separation systems is inadequately long, causing dilution of the eluted low-abundance protein samples. Here, we introduce an on-chip light-controlled reusable platform for the direct and fast depletion of highly abundant proteins from serum biosamples. Our nanoarrays display fast and highly selective depletion capabilities, up to 99% depletion of highly abundant protein species, with no undesired depletion effects on the concentration of low-abundance protein biomarkers. Displaying an ultrahigh surface area, ∼3400 m2 g-1, alongside a light-triggerable ultrafast release, this platform allows for a high depletion performance, together with high-yield reusability capabilities. Furthermore, this nanostructured light-controlled separation device could easily be integrated with downstream analytical technologies in a single lab-on-a-chip platform.