The recent development of silver nanostars (Ag-NSs) is promising for improved surface-enhanced sensing and spectroscopy, which may be further exploited if the mechanisms behind the excitation of localized surface plasmon resonances (LSPRs) are identified. Here, we show that LSPRs in Ag-NSs can be obtained with finite-difference time-domain (FDTD) calculations by considering the nanostars as combination of crossed nanorods (Ag-NRs). In particular, we demonstrate that an apparent tail at large wavelengths ( $\lambda \gtrsim 700$ nm) observed in the extinction spectra of Ag-NSs is due to a strong dipolar plasmon resonance, with no need to invoke heterogeneity (different number of arms) effects as is normally done in the literature. Our description also indicates a way to tune the strongest LSPR at desired wavelengths, which is useful for sensing applications.

Organometallic materials have become subject of intensive research on distinct technological applications. The Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) techniques have proven to be suitable to address challenges inherent to organic devices, in which the film properties can be tuned at molecular level. Here, we report on the supramolecular arrangement of zinc(II)-protoporphyrin(IX) dimethyl ester (ZnPPIX-DME) using the Langmuir, LB and LS techniques, leading to nanostructured films. The π-A isotherms showed that π-π stacking interaction among ZnPPIX-DME molecules takes place at the air/water interface, favoring the formation of Langmuir films closely packed. The controlled growth of the LB and LS films was monitored via UV-Vis absorption spectroscopy, with the thickness per monolayer within 1.3 and 1.7 nm. The homogeneous topography found at microscale is no longer preserved at nanoscale, which is found rougher according to AFM data. The FTIR indicated that the ZnPPIX-DME is isotropically arranged on both LB and LS films

Gold shell-isolated nanoparticles (AuSHINs) are promising photothermal therapy (PTT) agents for cancer treatment due to their excellent photoconversion efficiency, biocompatibility, colloidal stability, and tunable properties, including size, shape, and surface functionalization. However, their therapeutic efficacy in in vitro assays is often limited by poor cellular uptake and lysosomal entrapment, which can result in nanoparticle degradation and a reduction in PTT effectiveness. In this study, we demonstrate that nanostraw-assisted injection enhances the PTT efficacy of AuSHINs compared to the conventional incubation method, as evaluated in human breast cancer cell lines: adenocarcinoma cells (MDA-MB-231) and glandular carcinoma cells (MCF7). This enhancement is attributed to three differences between the delivery methods: nanoparticle internalization, intracellular targeting, and the progression of cell death pathways. Nanostraw injection resulted in approximately 10-fold higher internalization of AuSHINs compared to 0.5-h incubation. Confocal fluorescence microscopy revealed that AuSHINs delivered via conventional incubation predominantly localize within lysosomes, whereas those introduced through nanostraw-assisted injection primarily targeted the endoplasmic reticulum (ER), thus avoiding lysosomal degradation. This differential targeting led to approximately a 2-fold higher reduction in the viability of photoactivated breast cancer cells treated with nanostraw-delivered AuSHINs. Furthermore, nanostraw-assisted injection accelerated the initiation of apoptosis relative to incubation. PTT-induced cell death was more pronounced in MCF7 cells compared to MDA-MB-231 cells, reflecting the higher resistance to therapy of the latter. These findings highlight the potential of nanostraw-assisted injection to enhance PTT, and we now face the challenge of integrating it into in vivo delivery strategies.