Thermosensitive mixed shell polymeric micelles decorated with gold nanoparticles at the outmost surface: tunable surface plasmon resonance and enhanced catalytic properties with excellent colloidal stability

Abstract

Hybrid particulate composites consisting of noble metal nanoparticles (NPs) and polymeric particles have attracted intensive interest, due to the possibility of combining the precious optical and catalytic properties of the former with the stimuli responsiveness and biocompatibility of the latter. However, it is challenging to prepare hybrid particles that simultaneously have tunable optical and catalytic properties as well as excellent colloidal stability. In the current work, we report a strategy for such hybrid particles, through covalently decorating the outmost surface of mixed shell polymeric micelles (MSPMs) with gold NPs. For this, two block polymers, poly(3-caprolactone)-block-(ethylene glycol) (PCL-b-PEG) and poly(3caprolactone)-block-poly(N-isopropylacrylamide) (PCL-b-PNIPAM), were prepared by ring-opening polymerization and reversible addition fragmentation chain transfer (RAFT) polymerization, respectively. Co-self-assembly of the two block polymers result in MSPMs with a PCL core and a mixed shell consisting of PEG and PNIPAM. At the end of each PNIPAM chain in the shell, thiol groups are introduced to act as anchors for the in situ formation of gold NPs. The number density of the gold NPs is conveniently tuned through varying the relative amount of PEG/PNIPAM in the micellar shell. Reversible shrinking and extension of the PNIPAM chains regulated by temperature can be used to tune the interparticle distance of the gold NPs, while the whole hybrid particles are stabilized by the stretched PEG chains. The hybrid polymeric micelles exhibit thermoresponsive surface plasmon resonance and enhanced catalytic properties as well as excellent colloidal stability. † Electronic supplementary information (ESI) available: XPS, TEM images of gold NP decorated polymeric micelles of PNIPAM or MSPMs of a PEG/PNIPAM mass ratio 1 : 9 aer heating, UV-vis absorption spectra during the reduction of 4-NP catalyzed by pure gold NPs or MSPM@AuNPs aer heating, See

Recent Advances of Using Hybrid Nanocarriers in Remotely Controlled Therapeutic Delivery

“…Magnetic hyperthermia can induce coarsening of magnetic nanoparticles encapsulated inside the micelles system as well as core–shell disruption, which can lead to the rupture of the spherical nanovehicles and burst release of the contained drug payloads. Yin et al reported a method for the synthesis of hybrid particles, by chemically conjugating the corona of mixed shell polymeric micelles with GNPs . Poly(ε‐caprolactone) (PCL) is a biodegradable and biocompatible member in polyester family that have been widely employed as biomaterials.…”

Planet–Satellite Nanostructures Based on Block Copolymer‐Surfactant Nanoparticles Surface‐Decorated with Gold and Silver: A New Strategy for Interfacial Catalysis

“…Gold (Au) and silver (Ag) nanoparticles (NPs) have been extensively studied in the last years due to their tunable properties, such as size, shape, and surface, making them suitable for applications in a wide range of fields including catalysis, sensors and nanomedicine . More recently, the conjugation of metal NPs to other nanomaterials, including polymer‐based structures (micelles, microgels, particles), carbon nanotubes, dendrimers, cellulose nanocrystals, silica, and other inorganic nanoparticles were the subject of various studies resulting in the proposition of novel applications. Among the different types of conjugates investigated, hybrid nanostructures based on Ag and Au NPs and polymer‐based nanomaterials have received great attention.…”

“…Among the different types of conjugates investigated, hybrid nanostructures based on Ag and Au NPs and polymer‐based nanomaterials have received great attention. In these conjugates, the metal NPs can be located into the core, along the whole structure, or at the outer surface of the polymer‐based nanomaterials, in the last case generating planet–satellite nanostructures, in which the polymer‐based nanomaterial comprises the planet and the metal NPs, the satellites …”

“…The fabrication of polymer‐based planet–satellite nanostructures is particularly interesting because it was shown that the surface‐exposed metal NPs can be easily accessed by species in the surrounding media, a step that is crucial for catalysis and sensing purposes. Such a strategy also allows the control of the interparticle distance of surface‐located metal NPs which is well known to impact on their optical, electronic, and magnetic properties . Using this approach, several nanoconjugate systems have been described in the recent years, aiming at different potential applications.…”

“…Using this approach, several nanoconjugate systems have been described in the recent years, aiming at different potential applications. Block copolymer micelles: pH‐ and temperature‐responsive microgels and crosslinked polymer particles are examples of polymeric nanomaterials assembled with Au and Ag NPs which have been used for catalytic, stimuli‐responsive, and drug delivery purposes.…”