​Rewrit​e the following text into an academic literature review, which can replace the name of the major and make the logic more coherent. Remember to keep all literature citations : Ever since pure molecular entities have been adapted as drug, varied manifestations other than elimination of infections are frequently been acknowledged as side effects. Contemporary drug research focuses on these issues besides developing new molecules for the restoration of unnatural functional deviations in various tissues and organs (Dutta, 2007). Conventional delivery systems get diluted with tear, washed away through the lacrimal gland and usually require administering at regular time intervals whereas nanocarriers release drug at constant rate for a prolonged period of time and thus enhance its absorption and site specific delivery. (Wadhwa et. al., 2009) present an overview of the various aspects of the ocular drug delivery, with special emphasis on nanocarrier based strategies, including structure of eye, its barriers, delivery routes and the challenges/limitations associated with development of novel nanocarriers. (Sun et. al., 2013) study the research of nanoparticles as gene vector for tumor gene therapy. The gene therapy has been acknowledged as the major progress of modern medicine, also a focus . (Wang et. al., 2020) discuss the applications of protein-based nano-medicine with special emphasis on intracellular delivery/drug targeting ability for anticancer drugs. The types and targeting strategies of NDDSs were summarized, and the new research progress in the diagnosis and therapy of CVDs in recent years was reviewed (Deng et. al., 2020). (Zhang et. al., 2021) emphasize the powered mechanism of MNMs, including artificial and natural-based MNMs, and discuss the characteristics, as well as the challenges being faced by MNMs in drug delivery. (Cheng et. al., 2021) provide suggestions for more efficient adoption of nanomaterials in cancer therapy. (Wang et. al., 2022) focus on the latest progress in the applications of dendrimers as drug and gene carriers, including 1) active drug release strategies to dissociate drug/gene from dendrimer in response to stimuli; 2) size-adaptive and charge reversal dendrimer delivery systems that can better take advantage of the size and surface properties of dendrimer; 3) bulk and micro/nano dendrimer gel delivery systems. Other influential work includes (Dommelen et. al., 2011), (Zhang et. al., 2014).