Impact of Surface Charge-Tailored Gold Nanorods for Selective Targeting of Mitochondria in Breast Cancer Cells Using Photodynamic Therapy.

Herein, the impact of surface charge tailored of gold nanorods (GNRs) on breast cancer cells (MCF-7 and MDA-MB-231) upon conjugation with triphenylphosphonium (TPP) for improved photodynamic therapy (PDT) targeting mitochondria was studied. The salient features of the study are as follows: (i) positive (CTAB@GNRs) and negative (PSS-CTAB@GNRs) surface-charged gold nanorods were developed and characterized; (ii) the mitochondrial targeting efficiency of gold nanorods was improved by conjugating TPP molecules; (iii) the conjugated nanoprobes (TPP-CTAB@GNRs and TPP-PSS-CTAB@GNRs) were evaluated for PDT in the presence of photosensitizer (PS), 5-aminolevulinic acid (5-ALA) in breast cancer cells; (iv) both nanoprobes (TPP-CTAB@GNRs and TPP-PSS-CTAB@GNRs) induce apoptosis, damage DNA, generate reactive oxygen species, and decrease mitochondrial membrane potential upon 5-ALA-based PDT; and (v) 5-ALA-PDT of two nanoprobes (TPP-CTAB@GNRs and TPP-PSS-CTAB@GNRs) impact cell signaling (PI3K/AKT) pathway by upregulating proapoptotic genes and proteins. Based on the results, we confirm that the positively charged (rapid) nanoprobes are more advantageous than their negatively (slow) charged nanoprobes. However, depending on the kind and degree of cancer, both nanoprobes can serve as efficient agents for delivering anticancer therapy.

Triphenylphosphonium conjugated gold nanotriangles impact Pi3K/AKT pathway in breast cancer cells: a photodynamic therapy approach.

Although gold nanoparticles based photodynamic therapy (PDT) were reported to improve efficacy and specificity, the impact of surface charge in targeting cancer is still a challenge. Herein, we report gold nanotriangles (AuNTs) tuned with anionic and cationic surface charge conjugating triphenylphosphonium (TPP) targeting breast cancer cells with 5-aminoleuvinic acid (5-ALA) based PDT, in vitro. Optimized surface charge of AuNTs with and without TPP kill breast cancer cells. By combining, 5-ALA and PDT, the surface charge augmented AuNTs deliver improved cellular toxicity as revealed by MTT, fluorescent probes and flow cytometry. Further, the 5-ALA and PDT treatment in the presence of AuNTs impairs cell survival Pi3K/AKT signaling pathway causing mitochondrial dependent apoptosis. The cumulative findings demonstrate that, cationic AuNTs with TPP excel selective targeting of breast cancer cells in the presence of 5-ALA and PDT.

Biomimetic gold nanoparticles for its cytotoxicity and biocompatibility evidenced by fluorescence-based assays in cancer (MDA-MB-231) and non-cancerous (HEK-293) cells.

Biomimetic gold nanoparticles of biological origin have created a significant impact on the field of biomedicine due to the great expectations of its applications. Because of this, the influences of biomimetic gold nanoparticles have been immensely studied, targeting various cancer cells. However, the impact of biomimetic gold nanoparticles against normal non-cancerous cells is scanty, which impose several limitations in their utility. Taking this as a challenge, we in this study report the biomimetic gold nanoparticles from marine seaweed Gelidium pusillum (G. pusillum) to evaluate its cytotoxic and biocompatible ability evidenced by fluorescence-based assays in cultured cells. The gold nanoparticles obtained in the study were spherical shaped with a mean diameter of 12 ± 4.2 nm. The seaweed extract plays a crucial role in stabilizing the gold nanoparticles to avoid aggregation and coalescence. At an IC50 concentration of 43.09 ± 1.6 µgmL-1, the biomimetic gold nanoparticles were found to be toxic to cancerous cells (MDA-MB-231). Whereas, biomimetic gold nanoparticles exhibit significant biocompatibility with human embryonic kidney cells even at a higher concentration of 150 µgmL-1. The morphological based fluorescence assays confirmed the ability of biomimetic gold nanoparticles in inducing apoptosis and thereby kills cancer cells. Altogether, the gold nanoparticles were safe to normal cells and did not show a significant impact. Hence, the novel biomimetic gold nanoparticles hold potential as multifaceted agent and can further be taken up to various biomedical applications.

Macrocyclic "tet a" derived colorimetric sensor for the detection of mercury cations and hydrogen sulphate anions and its bio-imaging in living cells.

A mono-N-substituted probe L containing a bromosalicylaldehyde pendant arm attached to a tetraazamacrocyclic "tet a" moiety was synthesized via straight forward reaction. The probe L crystallizes in a monoclinic P21/n space group. The probe L displayed quick sensitivity and selectivity towards Hg2+ ions due to its hopeful Chelation Enhancement Quenching (CHEQ) feature. Interestingly, the probe L exhibits turn-off fluorescence response to Hg2+ ion and turn-on fluorescence signals to HSO4- ions. When the probe L was complexed with HSO4- in 1:1 mode (L + HSO4- formation), improved turn-on fluorescence emission was detected due to the chelation enhanced fluorescence effect through sensor complex. The macrocyclic "tet a" probe L exhibited a binding constant value of 3.89 × 106 M-1 and 5.58 × 105 M-1 for Hg2+ and HSO4-, respectively. Probe L exhibited good selectivity to Hg2+ rather than other common metal ions and HSO4- over other common anions. The limit of detection (LOD) of Hg2+ and HSO4- were found to be 1 nM and 7 µM, respectively. The time-resolved fluorescence emission single-photon counting study was used to determine the average lifetime value for the probe L and L + HSO4- ions as 0.47 and 1.02 ns, respectively. The practical application of the probe in visualizing intracellular Hg2+ and HSO4- ions distribution in live Artemia salina was demonstrated. Furthermore, the probe L with Hg2+cations was found to be cytotoxic against breast cancer cells in nature and can be delivered as an anticancer agent. Besides the probe L with HSO4- exhibit strong fluorescence emission with low cytotoxicity, and it can be recommended for live-cell imaging.