The most exciting phrase to hear in science, the one that heralds new discoveries,
is not 'Eureka!' (I found it!) but 'That's funny ...' - Isaac Asimov (1920 - 1992)
Systemic delivery of nucleic acids
Gene therapeutics overcome the limitations of traditional small molecule drugs (limited “druggable” targets) and protein drugs (size, stability). Due to the diverse functions of genes in living organisms, they are expected to address numerous diseases that have not been effectively treated with existing therapeutics. In particular, RNA therapeutics have gained significant interest in recent years as they circumvent the need for entering cell nuclei, which accounts for the safety concerns of DNA drugs. RNA therapeutics come in different forms and sizes, such as antisense oligonucleotides, aptamers, small interfering RNAs (siRNA), microRNAs, and messenger RNA (mRNA), playing diverse roles in disease progression. If they can be delivered to target sites safely and effectively, RNA therapeutics will dramatically change the landscape of pharmaceutical industry. The challenge is, and has always been, the effective delivery of RNA therapeutics. The existing RNA delivery strategies, albeit effective in vaccine delivery and local therapies, have fundamental limitations in treating diseases of extrahepatic organs due to the dependence of carriers on charge-based interactions with RNA. Moreover, the current carriers require cold chain storage, limiting their global distribution and use, as seen with mRNA vaccines. We have recently reported Nanosac, a non-cationic, flexible polyphenol-based nanocarrier, which overcomes the main limitations of existing RNA carriers. We are developing Nanosac for the systemic delivery of a broad range of RNA therapeutics in applications requiring extrahepatic delivery.
Nanoparticles for anticancer drug delivery
In developing safe and effective chemotherapy, it is essential to engineer a targeted drug delivery system that can selectively deliver antiproliferative drugs to tumor cells without affecting normal cells. While extensive efforts are made to enhance the recognition of drug carriers by tumor tissues, the targeting effect mostly depends on the imperfect vasculature of tumors, which leads to preferential extravasation of drug carriers. This limitation in the current targeting strategy is partly due to the diversity and heterogeneity of the tumor cells. It may also be related to the endothelium surrounding tumors, which limits drug carriers from accessing the underlying tissues. Another challenge in tumor-targeted drug delivery is that many drug carriers are not stable in blood. The instability of drug carriers leads to premature release of the entrapped drugs during circulation.
Long-acting drug delivery systems
One of the ultimate goals of controlled drug delivery is to maintain an effective plasma drug concentration for the desired period by providing a constant and extended supply of a drug. These products help reduce the frequency of administration and adverse effects related to drug level fluctuation, thus improving the effectiveness of therapy and the experience of patients. The development of long-acting drug delivery products requires flexible control of drug release kinetics according to the application. We are developing strategies to control drug release kinetics for different applications, ranging from post-surgical analgesia to chronic ocular disease therapy, which requires sustained and constant drug release anywhere between a few weeks to months.