Epidermal growth factor receptor-targeted poly(amidoamine)-based dendrimer complexed oncolytic adenovirus: is it safe totally?

Toxicity And Surface Modification Of Dendrimers: A Critical Review

As compared to other nano polymers, dendrimers have novel three dimensional, synthetic hyperbranched, nano-polymeric structures. The characteristic of these supramolecular dendritic structures has a high degree of significant surface as well as core functionality in the transportation of drugs for targeted therapy, specifically in host-guest response, gene transfer therapy and imaging of biological systems. However, there are conflicting shreds of evidence regarding biological safety and dendrimers toxicity due to their positive charge at the surface. It includes cytotoxicity, hemolytic toxicity, haematological toxicity, immunogenicity and in vivo toxicity. Therefore to resolve these problems surface modification of the dendrimer group is one of the methods. From that point, this review involves different strategies which reduce the toxicity and improve the biocompatibility of different types of dendrimers. From that viewpoint, we broaden the structural and safe characteristics of the dendrimers in the biomedical and pharmaceutical fields.

Synthesis and Evaluation of ¹⁹⁸Au/PAMAM-MPEG-FA against Cancer Cells

BACKGROUND

There is a significant dearth of clinical biochemistry researches to evaluate the facility of exploitation of folate targeted radioactive gold-labeled anti-cancer drugs against various cancer cell lines.

OBJECTIVE

The aim of this paper was to develop a gold-based compound with an efficient therapeutic potential against breast cancer. To this end, the synthesis of the 198Au/PAMAM-MPEG-FA composite was considered here.

METHODS

The radioactive gold (198Au) nanoparticles were encapsulated into Folic acid (FA)-targeted Polyamidoamine dendrimer (PAMAM) modified with Maleimide-Polyethylene glycol Succinimidyl Carboxymethyl ester (MPEG). After that, anticancer assessments of the prepared 198Au/PAMAM-MPEG-FA hybrid mater against breast cancer were investigated. Further studies were also devised to compare the anticancer capabilities of the 198Au/PAMAM-MPEG-FA composite with the synthesized P-MPEG, 197Au/P-MPEG, 197Au/P-MPEG-FA, 197Au/P-FA and 198Au/P-MPEG-FA conjugates. The prepared drugs were characterized by means of various analytical techniques. The radionuclidic purity of the 198Au/P-MPEG-FA solution was determined using High Purity Germanium (HPGe) spectroscopy and its stability in the presence of human serum was studied. The cell uptake and toxicity of the prepared drugs were evaluated in vitro, and some comparative studies of the toxicity of the drugs were conducted towards the MCF7 (Human breast cancer cell), 4T1 (Mice breast adenocarcinoma cell) and C2C12 (Mice muscle normal cell).

RESULTS

The results showed that cell uptake of 198Au/P-MPEG-FA nanoparticles is high in the 4T1 cell line and the order of uptake is as 4T1> MCF7> C2C12. Moreover, of the tested compounds, 198Au/P-MPEG-FA had the highest toxicity towards the cancerous 4T1 and MCF7 in all concentrations after 24, 48 and 72h (P < 0.001). Furthermore, the cytotoxicity of the drugs was concentration-dependent.

CONCLUSION

On the basis of the present research, 198Au/P-MPEG-FA has been proposed as a good candidate for the induction of cell death in breast cancer, although further experimental and clinical investigations are required.

New Advances in General Biomedical Applications of PAMAM Dendrimers

Dendrimers are nanoscopic compounds, which are monodispersed, and they are generally considered as homogeneous. PAMAM (polyamidoamine) was introduced in 1985, by Donald A. Tomalia, as a new class of polymers, named 'starburst polymers'. This important contribution of Professor Tomalia opened a new research field involving nanotechnological approaches. From then on, many groups have been using PAMAM for diverse applications in many areas, including biomedical applications. The possibility of either linking drugs and bioactive compounds, or entrapping them into the dendrimer frame can improve many relevant biological properties, such as bioavailability, solubility, and selectivity. Directing groups to reach selective delivery in a specific organ is one of the advanced applications of PAMAM. In this review, structural and safety aspects of PAMAM and its derivatives are discussed, and some relevant applications are briefly presented. Emphasis has been given to gene delivery and targeting drugs, as advanced delivery systems using PAMAM and an incentive for its use on neglected diseases are briefly mentioned.