Photosensitizer-peptoid conjugates for photoinactivation of Gram-negative bacteria: structure-activity relationship and mechanistic studies.

Multitarget engagement is considered an effective strategy to overcome the threat of bacterial infection, and antimicrobials with multiple mechanisms of action have been successful as natural chemical weaponry. Here, we synthesized a library of photosensitizer-peptoid conjugates (PsPCs) as novel antimicrobial photodynamic therapy (aPDT) agents. The peptoids, linkers, and photosensitizers were varied, and their structure-antimicrobial activity relationships against Escherichia coli were evaluated; PsPC 9 was indicated to be the most promising photoresponsive antimicrobial agent among the synthesized PsPCs.

Peptoid Helix Displaying Flavone and Porphyrin: Synthesis and Intramolecular Energy Transfer.

Natural light-harvesting complexes (LHCs) absorb a broad spectrum of sunlight using a collection of photosynthetic pigments whose spatial arrangement is controlled by a protein matrix and exhibit efficient energy transfer. We constructed a novel light-harvesting protein mimic, which absorbs light in the UV to visible region (280-700 nm) by displaying flavone and porphyrin on a peptoid helix. First, an efficient synthesis of 4'-derivatized 7-methoxyflavone (7-MF, and ) was developed.

Siloxane-Encapsulated Upconversion Nanoparticle Hybrid Composite with Highly Stable Photoluminescence against Heat and Moisture.

Herein, we report a siloxane-encapsulated upconversion nanoparticle hybrid composite (SE-UCNP), which exhibits excellent photoluminescence (PL) stability for over 40 days even at an elevated temperature, in high humidity, and in harsh chemicals. The SE-UCNP is synthesized through UV-induced free-radical polymerization of a sol-gel-derived UCNP-containing oligosiloxane resin (UCNP-oligosiloxane). The siloxane matrix with a random network structure by Si-O-Si bonds successfully encapsulates the UCNPs with chemical linkages between the siloxane matrix and organic ligands on UCNPs.

Morphological evolution of upconversion nanoparticles and their biomedical signal generation.

Advancements in the fabrication of upconversion nanoparticles (UCNPs) for synthetic control can enable a broad range of applications in biomedical systems. Herein, we experimentally verified the role of the hydrothermal reaction (HR) time in the synthesis of NaYF:20%Yb/3%Er UCNPs on their morphological evolution and phase transformation at different temperatures. Characterizations of the as-prepared UCNPs were conducted using X-ray diffraction (XRD), electron microscopy and spectroscopy, and thermogravimetric and upconversion (UC) luminescence analysis.