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J. Qu and J. Zhang
such as cancer. There are three main reasons explaining this phenomenon. First, some
pathogenic mechanisms of these diseases remain poorly understood and there are still
debates on the role of aggregated proteins in these diseases. For instance, it remains
unknown which species are more toxic than other species. Second, aptamers are
thought to have difficulty in penetrating blood–brain barrier (BBB). Definitely, the
BBB that occurs along all blood capillaries in the brain is known to prevent the
delivery of macromolecules, including the aptamers. So delivery strategies must be
developed to cross the BBB, for instance, using nanoparticles or exosomes. Third,
another important factor concerned with the stability of aptamers in vivo is renal
filtration. The molecular mass of aptamers always ranges from 5 to 15 KD, which
indicates that aptamers are prone to renal filtration. However, the incorporation of
nanomaterials could reduce the renal filtration rates of aptamers. Therefore, more
aptamer-nanomaterial conjugates should be developed to decrease the renal filtration
and improve the therapeutic efficiency of aptamers.
Overall, we believe that the application of aptamers in neurodegenerative disorders
has only just begun and would be massively extended in the near future.
References
1. Bruno JG (2015) Predicting the uncertain future of aptamer-based diagnostics and therapeutics. Molecules 20(4):6866–6887. https://doi.org/10.3390/molecules20046866
2. Santosh B, Yadava PK (2014) Nucleic acid aptamers: research tools in disease diagnostics
and therapeutics. Biomed Res Int 2014:540451. https://doi.org/10.1155/2014/540451
3. Pei X, Zhang J, Liu J (2014) Clinical applications of nucleic acid aptamers in cancer. Mol
Clin Oncol 2(3):341–348. https://doi.org/10.3892/mco.2014.255
4. Ellington AD, Szostak JW (1990) In vitro selection of RNA molecules that bind specific
ligands. Nature 346(6287):818–822. https://doi.org/10.1038/346818a0
5. Khoshbin Z, Housaindokht MR, Verdian A (2020) A low-cost paper-based aptasensor for
simultaneous trace-level monitoring of mercury (II) and silver (I) ions. Anal Biochem:113689.
https://doi.org/10.1016/j.ab.2020.113689
6. Mannironi C, Scerch C, Fruscoloni P, Tocchini-Valentini GP (2000) Molecular recognition of
amino acids by RNA aptamers: the evolution into an L-tyrosine binder of a dopamine-binding
RNA motif. RNA 6(4):520–527. https://doi.org/10.1017/s1355838200991763
7. Williams KP, Liu XH, Schumacher TN, Lin HY, Ausiello DA, Kim PS, Bartel DP (1997)
Bioactive and nuclease-resistant L-DNA ligand of vasopressin. Proc Natl Acad Sci USA
94(21):11285–11290. https://doi.org/10.1073/pnas.94.21.11285
8. Karimzadeh A, Hasanzadeh M, Shadjou N (2019) Bio-assay: the best alternative for conventional methods in detection of epidermal growth factor. Int J Biol Macromol 133:624–639.
https://doi.org/10.1016/j.ijbiomac.2019.04.121
9. Chen HW, Medley CD, Sefah K, Shangguan D, Tang Z, Meng L, Smith JE, Tan W
(2008) Molecular recognition of small-cell lung cancer cells using aptamers. ChemMedChem
3(6):991–1001. https://doi.org/10.1002/cmdc.200800030
10. Tang Z, Shangguan D, Wang K, Shi H, Sefah K, Mallikratchy P, Chen HW, Li Y, Tan W
(2007) Selection of aptamers for molecular recognition and characterization of cancer cells.
Anal Chem 79(13):4900–4907. https://doi.org/10.1021/ac070189y
11. Lorger M, Engstler M, Homann M, Goringer HU (2003) Targeting the variable surface
of African trypanosomes with variant surface glycoprotein-specific, serum-stable RNA
aptamers. Eukaryot Cell 2(1):84–94. https://doi.org/10.1128/ec.2.1.84-94.2003
J. Qu and J. Zhang
such as cancer. There are three main reasons explaining this phenomenon. First, some
pathogenic mechanisms of these diseases remain poorly understood and there are still
debates on the role of aggregated proteins in these diseases. For instance, it remains
unknown which species are more toxic than other species. Second, aptamers are
thought to have difficulty in penetrating blood–brain barrier (BBB). Definitely, the
BBB that occurs along all blood capillaries in the brain is known to prevent the
delivery of macromolecules, including the aptamers. So delivery strategies must be
developed to cross the BBB, for instance, using nanoparticles or exosomes. Third,
another important factor concerned with the stability of aptamers in vivo is renal
filtration. The molecular mass of aptamers always ranges from 5 to 15 KD, which
indicates that aptamers are prone to renal filtration. However, the incorporation of
nanomaterials could reduce the renal filtration rates of aptamers. Therefore, more
aptamer-nanomaterial conjugates should be developed to decrease the renal filtration
and improve the therapeutic efficiency of aptamers.
Overall, we believe that the application of aptamers in neurodegenerative disorders
has only just begun and would be massively extended in the near future.
References
1. Bruno JG (2015) Predicting the uncertain future of aptamer-based diagnostics and therapeutics. Molecules 20(4):6866–6887. https://doi.org/10.3390/molecules20046866
2. Santosh B, Yadava PK (2014) Nucleic acid aptamers: research tools in disease diagnostics
and therapeutics. Biomed Res Int 2014:540451. https://doi.org/10.1155/2014/540451
3. Pei X, Zhang J, Liu J (2014) Clinical applications of nucleic acid aptamers in cancer. Mol
Clin Oncol 2(3):341–348. https://doi.org/10.3892/mco.2014.255
4. Ellington AD, Szostak JW (1990) In vitro selection of RNA molecules that bind specific
ligands. Nature 346(6287):818–822. https://doi.org/10.1038/346818a0
5. Khoshbin Z, Housaindokht MR, Verdian A (2020) A low-cost paper-based aptasensor for
simultaneous trace-level monitoring of mercury (II) and silver (I) ions. Anal Biochem:113689.
https://doi.org/10.1016/j.ab.2020.113689
6. Mannironi C, Scerch C, Fruscoloni P, Tocchini-Valentini GP (2000) Molecular recognition of
amino acids by RNA aptamers: the evolution into an L-tyrosine binder of a dopamine-binding
RNA motif. RNA 6(4):520–527. https://doi.org/10.1017/s1355838200991763
7. Williams KP, Liu XH, Schumacher TN, Lin HY, Ausiello DA, Kim PS, Bartel DP (1997)
Bioactive and nuclease-resistant L-DNA ligand of vasopressin. Proc Natl Acad Sci USA
94(21):11285–11290. https://doi.org/10.1073/pnas.94.21.11285
8. Karimzadeh A, Hasanzadeh M, Shadjou N (2019) Bio-assay: the best alternative for conventional methods in detection of epidermal growth factor. Int J Biol Macromol 133:624–639.
https://doi.org/10.1016/j.ijbiomac.2019.04.121
9. Chen HW, Medley CD, Sefah K, Shangguan D, Tang Z, Meng L, Smith JE, Tan W
(2008) Molecular recognition of small-cell lung cancer cells using aptamers. ChemMedChem
3(6):991–1001. https://doi.org/10.1002/cmdc.200800030
10. Tang Z, Shangguan D, Wang K, Shi H, Sefah K, Mallikratchy P, Chen HW, Li Y, Tan W
(2007) Selection of aptamers for molecular recognition and characterization of cancer cells.
Anal Chem 79(13):4900–4907. https://doi.org/10.1021/ac070189y
11. Lorger M, Engstler M, Homann M, Goringer HU (2003) Targeting the variable surface
of African trypanosomes with variant surface glycoprotein-specific, serum-stable RNA
aptamers. Eukaryot Cell 2(1):84–94. https://doi.org/10.1128/ec.2.1.84-94.2003