Lysine gelators

Calcium alginate and poly-L-lysine Gelation Doxorubicin, oligonucleotides [28,89]... 

A dendritic two-component gelator was synthesised by Smith et al. on the basis of self-assembling acid-base/hydrogen bond interactions. Dendritic lysine building blocks serve as dendrons, and an aliphatic diamine as core (Fig. 2.12). Depending upon the choice of building blocks, the supramolecular complex forms fibrous gel phases by hierarchic self-organisation. 

Deming et al. [53-55] also described the formation of hydrogels from di-and triblock copolypeptides based on PLLeuio-4o and PLLysgo-sso (hydrobromide) gelation occurred at a polymer concentration as low as 0.25 wt %. It is thought that the scaffold of the hydrogel is built of twisted fibril assemblies with a core of closely packed poly(L-leucine) a-helices and a corona of cationic poly(L-lysine) chains. 

Diazocrown appended cholesterol gelators formed vesicular aggregates that have also been templated [59]. The spherical siHca structures obtained had two distinct diameters, 200 nm (interconnected spheres) and 2500 nm (isolated spheres) which closely resembled the initial gelator assembly. Poly(L-lysine), which also forms spherical aggregates (in the presence of a hydrophobic base additive), can be templated to give, as the end product, hollow siHca spheres of various diameters [60]. As yet no attempts have been made to control the aggregate size. 

Gemini gelators (e.g., N-lauroyl-L-lysine ethyl ester) Boc-Ala(l)-Aib(2)-P-Ala(3)-OMe (synthetic tripeptide) ... 

The repeating branched architecture can, in principle, be biodegraded into a relatively small number of similar building blocks, hi many cases dendrimers are constructed from biocompatible branched motifs, such as L-lysine or L-glutamic acid derivatives this may give rise to biocompatible gelators. 

Micro- and nanoparticles of alginate are effortlessly achieved by gelation with calcium ions. This property enables creation of a pre-gel consisting of miniature aggregates of gel particles, which can be tracked by the addition of an aqueous polycationic solution to make a polyelectrolyte complex coating. Poly-L-lysine (PLL) is a cationic natural polymer that has been used with alginates to formulate nanoparticles. 

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