using these materials for imaging tools as well as for therapeutics. Final fate of
graphene or radiographene was unexpectedly amusing that living body can handle
it metabolically. Organic nanomaterials are bodily ones but made of extrinsic
materials mostly polymers or liposomes/micelles. Scientific and pharmaceutical
community already cumulated lots of long-term experiences of using these classical
nanomaterials. Radiolabeling of these nanomedicines might expand their use and
thus looking back the successful use of drug-loaded nanomedicines will help the
readers to imagine and draw a picture of future of using radiolabeled organic
nanomaterials even including albumin. Understanding the role of albumin is still
underway. How to use radiolabeled organic nanomedicines for theranostic purposes
are to be investigated further.
Interestingly recently, we came to know that there are endogenous counterparts
of liposomes. Almost all of a sudden, these lipid bilayered extracellular vesicles or
exosomes produced endogenously by every kind of cells are circulating in the body
in health and diseases, and the exosomes are to find their appropriate position to
explain their roles in physiology. Extracellular vesicles, if they have the chances to
be used as carriers of familiar biomolecules from one cell to another, shall have
capability of being used as therapeutic or theranostic nanomedicines. What remains
to be understood is the whereabouts of these exosomes in the body after systemic
injection. The chapter of ‘extracellular vesicles’, a great synopsis with assuring
promise to the understanding the reason of existence of extracellular vesicles in
body are followed by technical details of new methods of radiolabeling of extracellular vesicles, the facts revealed about biodistribution elucidated using these
methods and the consequent prediction of the future use of these exosomes for
therapy and theranostics. In the strict description of the literature reports which tried
to figure out the distribution of systemically administered exosomes, one should
find the revelation that fluorescent dyes are not appropriate for finding or quantifying the distribution of exosomes. We still don’t know whether the membrane
labeling of intact exosomes or intracellular labeling of exosomes is appropriate
method to make us be able to estimate the biological effects when we injected
therapeutics-loaded exosomes. Notwithstanding validation of therapeutic potential,
the quantitative and/or qualitative distribution of endogenous or administered
exosomes should now be investigated. After long years of struggle to understand
the physiology or pathophysiology of exosomes and their subsets, and hopefully
before so long, the exosomes, either radiolabeled or not, will find a way to contribute to clinical nanomedicine.
It is well known that surface characteristics are crucial in determining the in vivo
behavior of nanomedicines. And there have been so many improvement of the
surface modification technology so far. The next move to the future facile use of
nanomedicines depends upon the optimization of surface modification of exosomes.
Along the surface modification one can also bind chelator which later chelates
radionuclides, which will yield radionanomedicines. These radionanomedicines are
going to be used for further characterization of biodistribution, quantification of
successful targeted delivery and clearance from the body. Investigators feel really
curious of the consequences of the surface modification or even radiolabeling in
6
D. S. Lee
graphene or radiographene was unexpectedly amusing that living body can handle
it metabolically. Organic nanomaterials are bodily ones but made of extrinsic
materials mostly polymers or liposomes/micelles. Scientific and pharmaceutical
community already cumulated lots of long-term experiences of using these classical
nanomaterials. Radiolabeling of these nanomedicines might expand their use and
thus looking back the successful use of drug-loaded nanomedicines will help the
readers to imagine and draw a picture of future of using radiolabeled organic
nanomaterials even including albumin. Understanding the role of albumin is still
underway. How to use radiolabeled organic nanomedicines for theranostic purposes
are to be investigated further.
Interestingly recently, we came to know that there are endogenous counterparts
of liposomes. Almost all of a sudden, these lipid bilayered extracellular vesicles or
exosomes produced endogenously by every kind of cells are circulating in the body
in health and diseases, and the exosomes are to find their appropriate position to
explain their roles in physiology. Extracellular vesicles, if they have the chances to
be used as carriers of familiar biomolecules from one cell to another, shall have
capability of being used as therapeutic or theranostic nanomedicines. What remains
to be understood is the whereabouts of these exosomes in the body after systemic
injection. The chapter of ‘extracellular vesicles’, a great synopsis with assuring
promise to the understanding the reason of existence of extracellular vesicles in
body are followed by technical details of new methods of radiolabeling of extracellular vesicles, the facts revealed about biodistribution elucidated using these
methods and the consequent prediction of the future use of these exosomes for
therapy and theranostics. In the strict description of the literature reports which tried
to figure out the distribution of systemically administered exosomes, one should
find the revelation that fluorescent dyes are not appropriate for finding or quantifying the distribution of exosomes. We still don’t know whether the membrane
labeling of intact exosomes or intracellular labeling of exosomes is appropriate
method to make us be able to estimate the biological effects when we injected
therapeutics-loaded exosomes. Notwithstanding validation of therapeutic potential,
the quantitative and/or qualitative distribution of endogenous or administered
exosomes should now be investigated. After long years of struggle to understand
the physiology or pathophysiology of exosomes and their subsets, and hopefully
before so long, the exosomes, either radiolabeled or not, will find a way to contribute to clinical nanomedicine.
It is well known that surface characteristics are crucial in determining the in vivo
behavior of nanomedicines. And there have been so many improvement of the
surface modification technology so far. The next move to the future facile use of
nanomedicines depends upon the optimization of surface modification of exosomes.
Along the surface modification one can also bind chelator which later chelates
radionuclides, which will yield radionanomedicines. These radionanomedicines are
going to be used for further characterization of biodistribution, quantification of
successful targeted delivery and clearance from the body. Investigators feel really
curious of the consequences of the surface modification or even radiolabeling in
6
D. S. Lee