Dendrimers - an Overview of Intellectual Property and Patenting Issues

Topics Covered


How Dendritic NanoTechnologies (DNT) Came to Dominate the Patenting Sector for Dendrimers

Patenting Dendrimers - a Summary of the Current Situation


Dendrimer IP is a “hot potato” because the potential for profit is enormous but commercialization is slow and uncertain - everyone wants to be holding key dendrimer patents at just the right time. Dendritech, a private company spun off from Dow and founded by Donald Tomalia in 1992, sold its dendrimer patents back to Dow in 2000. Then Tomalia left Dendritech and founded a new company, Dendritic NanoTechnologies Inc. (DNT). In January 2005, DNT acquired the mother lode of dendrimer patents when Dow turned over its entire intellectual property portfolio on dendrimers (196 patents worldwide) to DNT in exchange for owning a significant stake in the company.

AZoNano, Nanotechnology - Chart showing US patents and patent applications referring to dendrimers in the patent abstract, from 1999 to 2004.

Figure 1. US patents and patent applications referring to dendrimers in the patent abstract, from 1999 to 2004.

How Dendritic NanoTechnologies (DNT) Came to Dominate the Patenting Sector for Dendrimers

A third company, Starpharma (Melbourne, Australia), which already owned a chunk of DNT, increased its financial stake in the company to 49.9% and also gained exclusive rights to DNT’s and Dow’s intellectual property for dendrimer-based pharmaceutical applications. The flip-flopping dendrimer patent portfolio is now in the hands of DNT which claims to control “the world’s broadest intellectual property position in dendrimer science.” Today, DNT sells and licenses more than 200 variations of dendrimers to pharmaceutical, biotechnology and diagnostic companies. 

Table 1. Patents on dendrimers issued by the US PTO (survey conducted on 2 May 2005).

Top Assignees - 272 patents total


Number of patents

Dow Chemical* - these

patents are now owned

by Dendritic

NanoTechnologies Inc.



Bayer AG



Phillips Petroleum




Xerox Corporation






Dendritech, Inc.



Ford Motor Company**



University of California



ExxonMobil Chemical

Patents Inc.***







* includes Dow Corning Toray Silicone Co., Ltd. and Dow Corning Corporation;
** includes Ford Global Technologies;
*** includes Exxon Research and Engineering Co
**** includes Bridgestone Tire Company.

Patenting Dendrimers - a Summary of the Current Situation

•        Dendritic Nanotechnologies, Inc. clearly holds a dominant position in the dendrimer patent arena.

•        The 272 dendrimer patents issued between 1999-2004 were examined by 120 different patent examiners. The lack of uniform handling could result in overlapping and conflicting patents.

•        The list of top assignees reveals a particularly broad area of potential industrial applications for dendrimer technology, ranging from oil, pharma, rubber, automotive and even cosmetics.

•        While there is uncertainty about the future commercial value of dendrimer IP, there is little room for new, would-be innovators to enter the field without seeking multiple licenses - which may or may not be available from companies seeking to dominate the field.

•        The number of issued patents relating to dendrimers has declined every year since 2001. However, the number of dendrimer patent applications at US PTO is rising steadily.     

Source: ETC Group report entitled ‘Nanotech’s “Second Nature” Patents: Implications for the Global South’, April/May 2005.

For more information on this source please visit the ETC Group

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