Protein analysis is always one of the key fields researchers focus on. Recent years has witnessed the rapid development of novel nanomaterials and microfluidic droplets as ideal reactors for protein analysis. This article reviews the recent advances regarding the development of nanomaterial-based nanoreactors and microfluidic droplet reactors and their applications in protein analysis, especially in proteomics. The categories, features and applications of various recently developed micro/nano-reactors have been summarized and future directions and challenges in this field have also been discussed.

•AuNPs/APTMS ITO was fabricated for cell capture.•Folic acid-CdSe/ZnS QDs complex has been successfully labeled with tumor cells.•The constructed electrochemical assay was used to the determination of tumor cells.A new electrochemical assay strategy was proposed based on the specific recognition of folate receptors on a cell surface to folic acids. Indium tin oxide glass (ITO) surfaces were silanized by (3-aminopropyl) trimethoxylsilane (APTMS) to associate to Au nanoparticles (AuNPs) which can effectively capture cells. Then, CdSe/ZnS quantum dots (QDs)-labeled folic acids (FAs) can couple with the folate receptors (FRs) on the KB cells, which can overexpress FRs. By square wave stripping voltammetry (SWSV), the developed electrochemical assay showed an excellent analytical performance for the sensitive detection of KB cells as low as 2000 cells mL− 1. The QDs-based electrochemical assay provides a rapid and reliable platform towards the tumor cell quantification and thus has the potential in the improvement of cancer diagnosis and treatment.