Title
Photoluminescence Mechanisms of Dual-Emission Fluorescent Silver Nanoclusters Fabricated by Human Hemoglobin Template: from Oxidation- and Aggregation-Induced Emission Enhancement to Targeted Drug Delivery and Cell Imaging
Author
Mojtaba Shamsipur, Fatemeh Molaabasi, Morteza Sarparast, Elahe Roshani, Zahra Vaezi, Mohsen Alipour, Karam Molaei, Hossein Naderi-Manesh, Saman Hosseinkhani
Year
2018
Journal
ACS Sustainable Chemistry & Engineering
Abstract
A novel fundamental understanding of the features of mechanism for the synthesis of luminescent silver nanoclusters (AgNCs) in human hemoglobin (Hb) as capping/reducing agent based upon simultaneously size transition and fluorescence enhancement phenomena is presented. The interesting features consist of both NC core oxidation and aggregation-induced emission (AIE) attributed to ligand-to-metal charge transfer (LMCT) or ligand-to-metal-metal charge transfer (LMMCT) from Ag(I)-Hb complexes (through oxygen, nitrogen, and sulfur atoms of Hb residues donation to the Ag(I) ions) forming Ag(0)@Ag(I)−Hb core−shell NCs, the origin and consequence of which being a dual emission/single excitation nanosystem with large stocks shift and high quantum yield obtained at even high temperature is a challenging subject, which is not reported until now. The bioconjugation of hyaluronic acid (HA) onto surfaces of Hb layer (HA/AgNCs) produced a biocompatible platform with doxorubicin drug (DOX) as DOX/HA/AgNCs for specific imaging and delivery of DOX via an efficient targeting of CD44-overexpressing cancer cells, which lead to an increased inhibition of tumor cell growth. Additionally, the cell viability analysis illustrated that the developed nanocarriers significantly enhanced the DOX uptake in HeLa cancer cells compared to HUVEC and HNCF-PI 52 normal cells allowing a selective cytotoxicity to HeLa cells. The suggested LMCT/LMMCT mechanism for emission source combined with such attractive properties as simple one pot non-toxic synthesis rout, long lifetime and large Stocks shift, excellent aqueous stability and photostability and easy functionalization capability with good cell viability, provided the possibility to AgNCs nanoprobe for use to better understanding of the nucleation and growth mechanisms via computational modeling techniques (e.g. DFT study) and also for fabrication of new nanoprobes for developing multifunctional applications in the bio-based chemical and electrochemical fields and in in-vivo research.
Instrument
J-715
Keywords
Circular dichroism, Secondary structure, Ligand binding, Protein folding, Nanostructures, Biochemistry, Materials