Microfluidic engineering of exosomes: editing cellular messages for precision therapeutics.

Study of extracellular vesicles (EVs), particularly exosomes, holds significant promise; however, it is technically challenging to define these small and molecularly diverse nanovesicles. With intrinsic molecular payload and biodegradability, molecular engineering of exosomes opens new avenues for mediating cellular responses and developing novel nano-delivery systems in precision therapeutics. Microfluidic lab-on-chip technology is playing pivotal roles in this emerging field.

Protein Arrays III: Reverse-Phase Protein Arrays.

The reverse-phase protein array (RPPA) is to use highly specific antibodies to interrogate pan or posttranslationally modified protein targets, such as phosphorylated proteins, particularly the proteins involved in cell signaling pathways. In this protocol we will cover the preparation of cell (or tissue) lysates, sample printing, antibody validation, antibody interrogation, signal amplification steps, imaging and data analysis. In this protocol, colorimetric catalyzed signal amplification (CSA) chemistry, fluorescence and near-infrared (NIR) based detection methods will be described.

Protein Arrays II: Antigen Arrays.

Antigen arrays are fabricated using various antigens such as DNA, histones, synthetic peptides, recombinant proteins, or cell extracts to detect autoantibodies in autoimmune diseases, alloantibodies in transplantation, drug-induced antibodies or cancer-induced antibodies in blood or cell culture supernatant. In this protocol, we will provide a step-by-step executable procedure to perform antigen arrays, including antigen preparation and printing, blocking, sample loading, array detection, imaging, and data analysis.

Protein Arrays I: Antibody Arrays.

Antibody arrays represent one of the very early protein array systems where antibodies are used to capture and detect target proteins in a high-throughput platform. The development of high-quality antibodies, nanomaterial-based novel detection probes, as well as innovative imaging technologies and computational tools has tremendously improved the sensitivity, specificity, and robustness of antibody arrays during the past decade. In this protocol we will incorporate the most updated innovations and developments of antibody arrays into the step-by-step experimental procedures.

A Nanoparticle-Decorated Biomolecule-Responsive Polymer Enables Robust Signaling Cascade for Biosensing.

To meet the increasing demands for ultrasensitivity in monitoring trace amounts of low-abundance early biomarkers or environmental toxins, the development of a robust sensing system is urgently needed. Here, a novel signal cascade strategy is reported via an ultrasensitive polymeric sensing system (UPSS) composed of gold nanoparticle (gNP)-decorated polymer, which enables gNP aggregation in polymeric network and electrical conductance change upon specific aptamer-based biomolecular recognition. Ultralow concentrations of thrombin (10 m) as well as a low molecular weight anatoxin (165 Da, 10 m) are detected selectively and reproducibly.