Introduction: Micro RNAs (miRNA) are 21 – 23 nucleotides long and regulate the expression of coding genes by binding imperfectly with their 3′ UTR region. The miRNA profile is altered in pathological processes, making miRNAs good targets for drug therapy. Restoration of down-regulated miRNA or inhibition of overexpressed miRNA to return miRNA to its normal state is the basis of miRNA-based therapy. This review focuses on nanocarriers used for the delivery of miRNA that confer physical stability to the unstable RNA structure, protect the RNA from nuclease degradation and aid in effective silencing of target genes. Areas covered: The necessity of the nanocarrier for the delivery of the miRNA is emphasized and the recent research on liposome-, metal- and polymer-mediated miRNA delivery for the inhibition or replacement of the disease-related miRNA is summarized. Expert opinion: The size, charge and surface properties of nanocarriers have to be tuned to ensure effective and safe delivery of the miRNA in clinical practice. The immune responses related to the nanocarriers and the double-stranded nucleotide delivery remain to be addressed. Also, the binding of miRNAs to non-specific targets has to be studied in more detail because miRNAs have multiple targets due to partial binding unlike siRNA.

Dermal tissue engineering focuses on the restoration of diseased and damaged tissues by using a combination of cells, biomaterials, and bioactive molecules. Inorganic substances like zeolites, clay, mesoporous silica, metals, and metal oxides are advanced materials used in wound healing research. They can improve the structural stability and bioactivity of bio polymeric scaffolds. Zeolites, clays, and mesoporous silica act as suitable carriers for drug delivery and when incorporated within scaffolds, serve as ideal matrices for promoting skin regeneration. This review focuses on various natural polymers/inorganic materials based composite scaffolds used for skin tissue engineering, highlighting their synthesis routes and mode of action by which wound healing is enhanced. Among the different inorganic materials used, the role of zeolites incorporated biocomposites for promoting blood coagulation, antibacterial effect; oxygen delivery to cells and wound healing are discussed in detail. The article thus includes recent attempts to explore the hidden potential of inorganic materials in dermal tissue engineering.