mtDNA-Specific Ultrasensitive Near-Infrared Fluorescent Probe Enables the Differentiation of Healthy and Apoptotic Cells

Abstract

Mitochondrial DNA (mtDNA) as a class of important genetic material is easily damaged, which can result in a series of metabolic diseases, hereditary disease, and so on. mtDNA is an ultrasensitive indicator for the health of living cells due to the extremely short physiological response time of mtDNA toward damage (ca. 5.0 min). Therefore, the development of specific ultrasensitive fluorescent probes that can in real-time monitor mtDNA in vivo are of great value. With this research, we developed a near-infrared twisted intramolecular charge transfer (TICT) fluorescent probe YON. YON is a thread-like molecule with an A−π–D−π–A structure, based on the dicyanoisophorone fluorophore. The molecular design of YON enabled the specific binding with dsDNA (binding constant (K) = 8.5 × 105 M–1) within 1.3 min. And the appropriate water–oil amphiphilicity makes YON significantly accumulate in the mitochondria, enabling the specific binding to mtDNA. The fluorescence intensity at 640 nm of YON enhanced linearly with increasing concentrations of mtDNA. Dicyanoisophorone as the strong electron-withdrawing group that was introduced into both ends of the molecule resulted in YON being a classic quadrupole, so it could ultrasensitively detect trace mtDNA. The minimum detection limit was 71 ng/mL. Moreover, the large Stokes shift (λex = 435 nm, λem = 640 nm) makes YON suitable for “interference-free” imaging of mtDNA. Therefore, YON was used to monitor trace changes of mtDNA in living cells; more importantly, it could be used to evaluate the health of cells by monitoring microchanges of mtDNA, enabling the ultrasensitive evaluation of apoptosis.

Synergistically activated dual-locked fluorescent probes to monitor H2S-induced DNA damage

“…S14, ESI †). This was because mtDNA is more vulnerable to damage by H 2 S than nDNA [5][6][7]12 In contrast, the fluorescence intensity of ND-N 3 was enhanced, since it only interacts with H 2 S. These imaging results verified that NAN0-N 3 and NAN6-N 3 were suitable for the specific and highly sensitive imaging of nDNA and mtDNA damage induced by H 2 S, respectively. mtDNA can be used as a sensitive marker to distinguish healthy cells from apoptotic cells.…”

“…Fluorescent probes are typically composed of a fluorophore, linker, and recognition group. They have been used as effective tools for the visual monitoring of H 2 S [8][9][10][11] and DNA [12][13][14][15] in living cells. For example, an off-on probe with a symmetric structure and dual recognition sites has been developed for H 2 S that exhibits a low detection limit (2.0 Â 10 À5 mM) by using -N 3 as the recognition group in a bis-naphthalimide.…”

“…mtDNA can be used as a sensitive marker to distinguish healthy cells from apoptotic cells. 12 Thus, NAN6-N 3 was anticipated to be a powerful tool for evaluating the degree of apoptosis.…”

“…8 In addition, we have used thread-like probes based on dicyanoisoflurone as the fluorophore to specifically bind mtDNA at 7.1 × 10 −2 μg mL −1 generating a highly sensitive fluorescence response due to the inhibition of intramolecular torsion. 12 These previous systems exhibit excellent detection and monitoring ability based on different kinds of fluorescence signal changes. To date, most research has focused on structural modification of the fluorophore and recognition groups and has ignored the importance of the linker.…”

Recent Progress in Fluorescent Probes for Diabetes Visualization and Drug Therapy

“…(4) There are obvious fluorescence changes before and after recognition. (5) The probe has a certain membrane penetration and low photobleaching and photodamage, which can avoid the interference of autofluorescence of organisms such as near-infrared (NIR) luminescence and two-photon imaging [39][40][41][42][43].…”