Intelligent delivery systems are a promising method to protect bioactive molecules from degradation and improve their bioavailability.
Due to their biophysical properties, liposomes can deliver and specifically target a large set of bioactive molecules, they can protect molecules from degradation, and their composition is easily modifiable.
Poly(lactic-co-glycolic acid) (PLGA), a US Food and Drug Administration (FDA -approved copolymer, has been exploited widely in the design oFDA -approvedes becopolymeris biodegradable, biocompatible, protects thasdrug molecules from degradation, and aids in producing sustained and targeted delivery.
HSA may protect drug molecules from degradation, increase water solubility, increase drug absorption by facilitating diffusion through epithelium, change the drug tissue distribution profile and pharmacokinetic, and/or improve intracellular penetration and distribution [4, 5, 6, 7, 8, 9, 10].
Our experiments show that crystalline surfaces of minerals could have facilitated life's origins by selecting and concentrating biomolecules, protecting those molecules from degradation, and promoting a host of biochemical reactions.
Among these delivery systems, liposomes represent a promising technology for the delivery of macromolecules into cells for the following reasons: (1) they are non-cytotoxic; (2), they can deliver and specifically target a large set of bioactive molecules (such as proteins, DNA or ribozymes); (3), they can protect molecules from degradation; and (4), their composition is easily modifiable.
However, it was recently demonstrated that chemical modification can protect the siRNA molecule from degradation [ 70] and might even prolong the silencing effect due to slower depletion within the cell [ 71].
In the nucleus, the ends of the linear chromosomes are capped by repetitive sequences known as telomeres that both protect the molecule from degradation and allow its replication in a faithful manner (i.e., without the loss of essential sequences).
Indeed, in addition to the well-established role of the poly-(A) tail, which confers protection to the RNA molecule from degradation by exonucleases, resulting in enhancement of translation, there are a number of motif sequences within the 3'-UTR that regulate mRNA stability and translational efficiency, including the recently identified microRNA-binding sites [ 22, 23].
For example, the OBP3 gene is a carrier of odor molecules, which can protect odor molecules from enzymatic degradation [ 17, 18].
At the same time, as internal factors, insect OBPs not only can selectively bind certain types of odor molecules, but also can remove toxic substances and protect the odor molecules from enzymatic degradation [ 17, 18].
