Electrochemical examination of ability of dsDNA/PAM composites for storing and releasing of doxorubicin

DNA-Polylactide Modified Biosensor for Electrochemical Determination of the DNA-Drugs and Aptamer-Aflatoxin M1 Interactions

DNA sensors were assembled by consecutive deposition of thiacalix[4]arenes bearing oligolactic fragments, poly(ethylene imine), and DNA onto the glassy carbon electrode. The assembling of the layers was monitored with scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The configuration of the thiacalix[4]arene core determined self-assembling of the polymeric species to the nano/micro particles with a size of 70–350 nm. Depending on the granulation, the coatings show the accumulation of a variety of DNA quantities, charges, and internal pore volumes. These parameters were used to optimize the DNA sensors based on these coatings. Thus, doxorubicin was determined to have limits of detection of 0.01 nM (cone configuration), 0.05 nM (partial cone configuration), and 0.10 nM (1,3-alternate configuration of the macrocycle core). Substitution of native DNA with aptamer specific to aflatoxin M1 resulted in the detection of the toxin in the range of 20 to 200 ng/L (limit of detection 5 ng/L). The aptasensor was tested in spiked milk samples and showed a recovery of 80 and 85% for 20 and 50 ng/L of the aflatoxin M1, respectively.

Switchable conformational changes of DNA nanogel shells containing disulfide–DNA hybrids for controlled drug release and efficient anticancer action

Oligonucleotide strands containing dithiol (–SS–) groups were used as the co-crosslinkers in PNIPA–AAc based nanogels (NGs). They hybridized with PEG–oligonucleotides introduced into the gels. The specific DNA hybrid formed in the nanogel/nanocarrier was involved in highly efficient accumulation of intercalators. The presence of –SS– groups/bridges improved the storing efficiency of doxorubicin (Dox) in DNA hybrids by 53, 40 and 20% compared to regular, single stranded and regular double stranded DNA crosslinkers, respectively. The explicit arrangement of the hybrids in the carrier enabled their reduction by glutathione and an effective cancer treatment while the side toxicity could be reduced. Compared to the NGs with traditional crosslinkers and those containing typical dsDNA-based hybrids, an improved, switchable and controlled drug release occurred in the novel NGs. Since the novel NGs can release the oligonucleotide strands during their degradation, this gives an opportunity for a combined drug-gene therapy.

Switchable conformational changes of multiresponsive nanogels containing disulfide/DNA hybrid shells for pulsative drug release.

A degradable nanogel drug carrier crosslinked with three-oligonucleotide hybrids for two-way drug release in mild and high hyperthermia treatment

Three-segment oligonucleotide hybrids were introduced as crosslinkers to a PNIPA-AAc nanonetwork. The obtained nanogels could be specifically transformed and degraded. The specific architecture of the presented carrier aims at achieving effective cancer treatment with reduced side toxicity. As a result, compared to the gels with regular crosslinkers, the drug release could be independently realized by (a) changing the structure of the gel net and conformation of DNA hybrids in an oscillating way and (b) degradation of DNA crosslinkers by denaturation. The hydrodynamic diameter and zeta potential of the nanogels were examined as a function of T and pH. The presence of a DNA helix in the nanogels led to a substantial increase, of nearly three times, in the storing efficiency of the selected anticancer drug compared to the nanogels with regular crosslinkers. Moreover, the nanogels allowed 98% drug release efficiency at high hyperthermic and 70% at mild hyperthermic conditions. The effectiveness of cytotoxicity of insulinoma cells was better compared to free doxorubicin. Since in the proposed approach, in addition to the drug, the third DNA strand can be also liberated, this opens new possibilities in development of gene therapies. This novel biocompatible carrier exhibits enhanced drug loading, possesses tunable and degradable properties under hyperthermic conditions and offers controlled release of the drug.

Environmentally sensitive nanohydrogels decorated with a three-strand oligonucleotide helix for controlled loading and prolonged release of intercalators

Biocompatible nanohydrogels modified with three-segment oligonucleotide hybrids were used for controlled loading and prolonged release of anticancer intercalators in hyperthermia treatment.