Early detection and effective treatments are crucial for disease eradication and patient healing, and for survival and/or quality of life. Cancer is one of the pathologies that can benefit from both approaches, as many other illnesses. MicroRNAs (miRNA) represent an emerging tool which could be effective in either detecting or curing several conditions. miRNAs are short (18–25 nucleotides) noncoding single-stranded endogenous oligoribonucleotides, which are relatively stable; they are predominantly secreted in vesicles, or in a complex with other proteins. MiRNA’s role is linked to the regulation of different biological processes, such as cellular development, differentiation, proliferation, metabolism, and apoptosis ^[1]. In fact, they regulate gene expression, and the alterations in their expression levels correlate with the onset and progression of different diseases, such as tumours, cardiovascular and rheumatic diseases, and neurological disorders ^[2][3][4]. Under pathological conditions, dysregulated miRNA levels are observed, but the relationship between dysregulated miRNA levels and disease is not straightforward. The oncogenic or tumour-suppressive activities of miRNAs depend on which genes are activated or inhibited through the up- or downregulation of miRNA expression. Thus, to ensure a secure diagnosis, the identification of miRNAs via expression profiling is fundamental; this is because alteration in the expression levels of a single miRNA does not have sufficient diagnostic power compared to multiplexing, that is, the parallel or simultaneous detection of known multiple miRNAs. Current quantification strategies have limitations and disadvantages. In general, all quantification methods are divided into two categories—one that utilizes direct oligo-hybridization without sample RNA amplification, and the other requiring sample amplification. Methods that do not utilize sample amplification will require a relatively larger starting amount of total RNA, while the others requiring sample amplification, with external variation as they are handling imperfections, can also be amplified. Oligo-microarray technology is relatively low-cost and readily available; a disadvantage of this method is its scale, as the resulting array will be relatively large. Alternatively, the use of synthesis and chemical modification of RNA probes is costly and often requires a large amount of total RNA. Many other methods and tools have been developed for miRNA expression profiling. Problems such as sensitivity and specificity have been addressed through various strategies; however, they are still very expensive, since answering to a variety of specific needs; an appropriate sample size, sample quantity and speed; and the requirement to identify new miRNAs can be costly. Thus, there is a great interest in developing innovative methods, and nanotechnology-based approaches are particularly sought-after. Nanotechnology will have a strong impact on delivery and diagnosis through miRNA, demonstrating that the newly developed approach works on ‘real-world’ samples under standardized conditions. The same is true also for miRNA transport and delivery, as miRNA inhibition or mimicry are strategies currently under evaluation to maintain the level of miRNA inside the cells, and nanotechnology can offer a good solution to bring the miRNA mimics to the tumour site.

BIn this review, both approaches (detection and treatment) using nanotechnology-based strategies have been analysed, to point out the current trends in this promising field of bio-medical applications (Figure 1 and Figure 2).